Pharmacokinetics of long-acting cephapirin and cloxacillin after intramammary administration in dairy goats

Determining the pharmacokinetics of intramammary antimicrobials in goats can assist in predicting appropriate meat and milk withdrawal intervals for drugs that are effective at treating subclinical mastitis due to non-aureus Staphylococci during the dry period. Twenty-four healthy, lactating does were enrolled in this study. Half were administered 300 mg of cephapirin benzathine (ToMORROW, Boehringer Ingelheim Vetmedica, Duluth, GA) via intramammary infusion into each half of the udder. The remaining does had 500 mg cloxacillin benzathine (Orbenin DC, Merck & Co., Rahway, NJ) administered per half. Plasma was collected before treatment and for 7 days post-treatment followed by analysis via liquid chromatography with tandem mass spectroscopy. Pharmacokinetic parameters were determined using noncompartmental methods via commercial software (MonolixSuite). The mean maximum concentration (Cmax) of cephapirin of 0.073 μg/mL was noted at 7.06 h post-administration (Tmax). The area under the plasma concentration curve based on the final sampling point (AUClast) was 1.06 h × μg/mL. The mean residence time until the final sampling point (MRTlast) was 13.55 h. Mean terminal half-life (T½) of cephapirin was 6.98 h. In CLOX does, Cmax was 0.074 μg/mL with a Tmax of 18 h, AUClast was 5.71 h × μg/mL, T½ was 77.45 h, and MRTlast was 65.36 h. Despite both products being formulated with benzathine salts, marked differences were noted in pharmacokinetic parameters including AUC, T1/2, and MRTlast. This data will be used to plan sampling schedules for milk and tissue residue depletion studies for both products.

Whole-genome resequencing reveals candidate genes associated with milk production trait in Guanzhong dairy goats

Milk production is one of the most important economic utility of goats. Guanzhong dairy goat is a local dairy goat in Shaanxi Province of China and has high milk yield and quality. However, there are relatively few studies on molecular markers of milk production traits in Guanzhong dairy goats. In this study, we sequenced the whole genomes of 20 Guanzhong dairy goats, 10 of which had high milk yield (HM) and 10 of which had low milk yield (LM). We detected candidate signatures of selection in HM goats using Fst and π-ratio statistics and identified several candidate genes including ANPEP, ADRA1A and PRKG1 associated with milk production. Our results provide the basis for molecular breeding of milk production traits in Guanzhong dairy goats.

Influence of repeated estrus synchronization treatment on hormone secretion, growth, and development of dairy goats

In large-scale intensive farms, dairy goats often undergo frequent estrus synchronization (ES) treatment, which may result in a decline in reproductive performance; however, the underlying mechanism remains unclear. The present study aimed to investigate the effect of pregnant mare serum gonadotropin (PMSG) and progesterone (P4)-mediated ES treatment on fertility in dairy goats, while also identifying key metabolic and endocrine mechanisms that influence reproductive performance in does subjected to repeated ES treatment. Forty-eight Saanen does were randomly assigned to two groups (24 goats each) that received ES treatments either thrice fortnightly (3-PMSG) or once (1-PMSG) simultaneously with the third ES treatment of the 3-PMSG group during the breeding season. ES treatment was performed via the intravaginal insertion of a controlled internal drug release (CIDR) device impregnated with 300 mg P4, followed by 300 IU PMSG injections 48 h before CIDR withdrawal. Blood was collected to detect the level of hormones and blood biochemical indices. Additionally, estrus rate, fecundity rate, body weight, size, and lactation performance were measured. The results showed that repeated ES treatment markedly decreased the estrus rate and fecundity rate of goats. Among the does in all groups, there was no substantial difference in follicle stimulating hormone, luteinising hormone, gonadotropin-releasing hormone, melatonin, growth hormone, PMSG, total cholesterol, total protein, and glucose levels, as well as the body weight, body size, and lactation performance. Repeated ES treatment elevated estrogen (E2) levels 36, 48, and 72 h post-CIDR removal; increased P4 upon CIDR insertion; and raised PMSG antibody levels 24, 48, and 72 h post-CIDR removal. The results suggest that elevated anti-PMSG levels are the primary reason for the decline in ES efficiency, and that high E2 and P4 levels at some time points also impair reproductive performance. These findings provide novel insights into the metabolic effects of repeated PMSG stimulation in goats, guiding future reproductive hormone use in breeding practices.

Variations in Casein Genes Are Associated with Milk Protein and Fat Contents in Sarda Goats (Capra hircus), with an Important Role of CSN1S2 for Milk Yield

This work aimed to assess the variability of casein genes in a population of 153 bucks and 825 lactating does of the Sarda breed, and to perform association analysis between polymorphic sites and milk yield and composition traits. To genotype the casein genes, we chose an SNP panel including 44 SNPs mapping to the four casein genes CSN1S1, CSN2, CSN1S2, and CSN3. Genotyping (made by KASP™ genotyping assay, based on competitive allele-specific PCR) revealed the high variability of the Sarda goat, and haplotype analysis revealed linkage disequilibrium (LD) between CSN1S1 and CSN2 genes, in addition to two LD blocks within the CSN1S2 and two LD blocks within the CSN3 gene, in bucks and does. Association analysis revealed that variability at all four casein genes was associated with milk protein content, total solids, and milk energy. The three Ca-sensitive casein genes were associated with lipid content, and CSN1S2 showed a unique pattern, with intron variants associated with milk yield, in addition to milk pH, NaCl, and SCS (Somatic Cell Score). This information might prove useful in selection schemes and in future investigations aiming to better understand the biology of lactation, and the direct link between genotype and phenotype.

Curcumin alleviates bisphenol AF-induced oxidative stress and apoptosis in caprine endometrial epithelial cells via the Nrf2 signaling pathway

Bisphenol AF (BPAF), a BPA-substitute, has been widely used in industrial compounds throughout the world. Several studies have shown that BPAF has endocrine interference and reproductive toxicity. However, the toxic effects of BPAF on pregnancy and placenta of goats are still unclear. Therefore, the objective of this study was to reveal the toxic effect of BPAF by using an in vitro culture model of caprine endometrial epithelial cells (EECs) and further attempted to alleviate the toxicity by curcumin pretreatment. The results showed that BPAF induces significant effects on EECs, including decreased cell viability and mitochondrial membrane potential (△ψm), elevating intracellular reactive oxygen species (ROS), promoting cell apoptosis through upregulating the expression of Bax, Cytochrome c, and downregulating the expression of Bcl-2. Meanwhile, BPAF induced dysregulation of oxidative stress by increasing the levels of malondialdehyde (MDA) and glutathione peroxidase (GSH-Px) but decreasing the activities of superoxide dismutase (SOD). However, curcumin pretreatment could significantly attenuate BPAF-induced toxic effects in EECs. Further study revealed that BPAF treatment could activate mitogen-activated protein kinase (MAPK) pathway and nuclear factor-erythroid 2-related factor 2 (Nrf2) expression, but curcumin pretreatment significantly inhibited the activation of MAPK signal pathway and Nrf2 expression induced by BPAF. Overall, this study indicated that curcumin could prevent BPAF-induced EECs cytotoxicity, which provides a potential therapeutic strategy for female infertility associated with BPAF exposure.

Genome-wide association study for wattles trait in the dairy goat breed

Dairy goats are significant livestock that provide high-quality milk sources in the world. The wattles trait is an evident phenotypic character on the neck of a dairy goat, which is considered to be under genetic control. We collected samples of 189 dairy goats, including 94 with wattles and 95 without wattles, from four different farms and multiple dairy goat breeds. The samples were genotyped with the GeneSeek Genomic Profiler Goat 70 K SNP chip. Genome-wide association studies (GWAS) in wattles have identified associations with single nucleotide polymorphisms (SNPs) at chromosome 10. In this area, an extremely strong association locus was assigned to FMN1 (Formin 1) belongs to the formin homology family and is associated with limb deformity, other candidate genes of interest confirmed for wattles were ARHGAP11A (Rho GTPase Activating Protein 11 A) and GJD2 (Gap Junction Protein Delta 2). Meanwhile, we found the presence or absence of wattles had no significant effect on milk yield. This research will provide genetic resources useful to explore genetic factors affecting the trait.

The Relationship between Mastitis and Antimicrobial Peptide S100A7 Expression in Dairy Goats

S100A7 is an inflammation-related protein and plays an essential role in host defenses, yet there is little research about the relationship between mastitis and S100A7 expression in dairy goats. Here, according to the clinical diagnosis of udders, SCC, and bacteriological culture (BC) of milk, 84 dairy goats were grouped into healthy goats (n = 25), subclinical mastitis goats (n = 36), and clinical mastitis goats (n = 23). The S100A7 concentration in subclinical mastitis goats was significantly upregulated than in healthy dairy goats (p = 0.0056) and had a limited change with clinical mastitis dairy goats (p = 0.8222). The relationship between log10 SCC and S100A7 concentration in milk was positive and R = 0.05249; the regression equation was Y = 0.1446 × X + 12.54. According to the three groups, the log10 SCC and S100A7 were analyzed using the receiver operating characteristics (ROC) curve; in subclinical mastitis goats, the area under the ROC curve (AUC) of log10 SCC was 0.9222 and p < 0.0001, and the AUC of S100A7 concentration was 0.7317 and p = 0.0022, respectively; in clinical mastitis goats, the AUC of log10 SCC was 0.9678 and p < 0.0001, and the AUC of S100A7 concentration was 0.5487 and p = 0.5634, respectively. In healthy goats, S100A7 was expressed weakly in the alveolus of the mammary gland of healthy goats while expressed densely in the collapsed alveolus of mastitis goats. Moreover, S100A7 expression increased significantly in mastitis goats than in healthy dairy goats. In this research, results showed the effects of mastitis on the S100A7 expression in the mammary gland and S100A7 concentration in milk and the limited relationship between SCC and mastitis, which provided a new insight into S100A7's role in the host defenses of dairy goats.

Variations in Composition, Antioxidant Profile, and Physical Traits of Goat Milk within the Semi-Intensive Production System in Mountainous Areas during the Post-Weaning to End-of-Lactation Period

Dairy products from mountain-origin milk are known for their superior composition and quality. This study aimed to examine changes in composition, nutritional quality, and antioxidant properties of milk from semi-intensively managed goats in mountainous regions during the post-weaning to end-of-lactation period. Bulk tank milk samples from 10 farms were collected bi-weekly in the period from March to September. The farms were situated in regions with an average altitude of 772.20 m above sea level. The results revealed significant variations in milk composition, with fluctuations in fat, protein, lactose, and total solids. Milk yield per doe showed seasonal differences, with the highest yield in April and the lowest in September. Fatty acid composition exhibited changes throughout the sampling period, with variations in polyunsaturated fatty acids. Nutritional indices, such as the atherogenicity index and thrombogenicity index, remained within the recommended values. Antioxidant properties, including total phenolic content, DPPH, FRAP, and ABTS, showed significant differences, with higher values toward the end of the study. Milk pH, electrical conductivity, brix value, and refractive index also exhibited variations, while density and freezing point remained relatively stable. The study provided valuable information that can be used to develop breeding and feeding plans to achieve uniform milk quality in mountainous regions.

Characterization of the fatty acid binding protein 3 (FABP3) promoter and its transcriptional regulation by cAMP response element binding protein 1 (CREB1) in goat mammary epithelial cells

Fatty acid binding protein 3 (FABP3) is involved in signal transduction pathways, and in the uptake and utilization of long-chain fatty acids. However, the transcriptional regulation of FABP3 in goat is unclear. In this study, the FABP3 5' flanking region was amplified from goat (Capra hircus) genomic DNA. Luciferase reporter vectors containing promoter fragments of five different lengths were constructed and transfected into dairy goat mammary epithelial cells. The region of the promoter located between -1801 and -166 bp upstream of the transcription start site (TSS) exhibited the highest luciferase activity, and contained two cAMP response elements (CREs) located at -1632 bp and -189 bp. Interference with CREB1 significantly downregulated FABP3 promoter activity. In addition, FABP3 promoter activity was significantly reduced after mutation of the CRE1 (-1632 bp) and CRE2 (-189 bp) sites. Further analysis indicated that the CRE2 site was essential for the transcriptional activity induced by CREB1. These results demonstrated that CREB1 is involved in the transcriptional regulation of FABP3 expression in the goat mammary gland via a direct mechanism, thus revealing a novel signaling pathway involved in fatty acid metabolism in goat.

Interactive Dairy Goat Image Segmentation for Precision Livestock Farming

Semantic segmentation and instance segmentation based on deep learning play a significant role in intelligent dairy goat farming. However, these algorithms require a large amount of pixel-level dairy goat image annotations for model training. At present, users mainly use Labelme for pixel-level annotation of images, which makes it quite inefficient and time-consuming to obtain a high-quality annotation result. To reduce the annotation workload of dairy goat images, we propose a novel interactive segmentation model called UA-MHFF-DeepLabv3+, which employs layer-by-layer multi-head feature fusion (MHFF) and upsampling attention (UA) to improve the segmentation accuracy of the DeepLabv3+ on object boundaries and small objects. Experimental results show that our proposed model achieved state-of-the-art segmentation accuracy on the validation set of DGImgs compared with four previous state-of-the-art interactive segmentation models, and obtained 1.87 and 4.11 on mNoC@85 and mNoC@90, which are significantly lower than the best performance of the previous models of 3 and 5. Furthermore, to promote the implementation of our proposed algorithm, we design and develop a dairy goat image-annotation system named DGAnnotation for pixel-level annotation of dairy goat images. After the test, we found that it just takes 7.12 s to annotate a dairy goat instance with our developed DGAnnotation, which is five times faster than Labelme.

Identification and Characterization of circRNAs in Non-Lactating Dairy Goat Mammary Glands Reveal Their Regulatory Role in Mammary Cell Involution and Remodeling

This study conducted transcriptome sequencing of goat-mammary-gland tissue at the late lactation (LL), dry period (DP), and late gestation (LG) stages to reveal the expression characteristics and molecular functions of circRNAs during mammary involution. A total of 11,756 circRNAs were identified in this study, of which 2528 circRNAs were expressed in all three stages. The number of exonic circRNAs was the largest, and the least identified circRNAs were antisense circRNAs. circRNA source gene analysis found that 9282 circRNAs were derived from 3889 genes, and 127 circRNAs' source genes were unknown. Gene Ontology (GO) terms, such as histone modification, regulation of GTPase activity, and establishment or maintenance of cell polarity, were significantly enriched (FDR < 0.05), which indicates the functional diversity of circRNAs' source genes. A total of 218 differentially expressed circRNAs were identified during the non-lactation period. The number of specifically expressed circRNAs was the highest in the DP and the lowest in LL stages. These indicated temporal specificity of circRNA expression in mammary gland tissues at different developmental stages. In addition, this study also constructed circRNA-miRNA-mRNA competitive endogenous RNA (ceRNA) regulatory networks related to mammary development, immunity, substance metabolism, and apoptosis. These findings help understand the regulatory role of circRNAs in mammary cell involution and remodeling.

Glucose Starvation Inhibits Ferroptosis by Activating the LKB1/AMPK Signaling Pathway and Promotes the High Speed Linear Motility of Dairy Goat Sperm

In mammals, sperm acquire fertilization ability after capacitation in vitro or when in the female reproductive tract. The motility patterns of sperm undergo continuous changes from the moment of ejaculation until fertilization in the female reproductive tract. In vitro, hyperactivated motility can be induced through high glucose mediums, while in vivo, it is induced by oviduct fluids. Conversely, sperm maintain linear motility in seminal plasma or uterine fluids that contain low glucose levels. In dairy goat sperm, energy metabolism associated with capacitation depends on the energy sources in vitro, seminal plasma, or the female reproductive tract, especially the glucose levels. However, there is little experimental knowledge that glucose levels affect sperm energy metabolism in dairy goats. To clarify these hypotheses, we incubated dairy goat spermatozoa with different concentrations of rotenone-glucose (ROT), carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP), and tigecycline (TIG) in vitro. Sperm motility attributes, ATP content, pyruvate and lactate levels, mitochondrial permeability transition pore fluorescence intensity, mitochondrial membrane potential (MMP), and protein synthesis were analyzed. Sperm motility patterns changed from circular to linear under low glucose conditions compared with those in high glucose conditions and showed a significant improvement in progressive motility and straight line speed, whereas lactate and pyruvate levels and MMP decreased remarkably. Incubation of spermatozoa with ROT, FCCP, and TIG inhibited sperm mitochondrial activity, protein synthesis, oxidative phosphorylation, and ATP levels, thereby reducing sperm motility, including the progressive motility, straight line speed, and total motility. Simultaneously, incubation of spermatozoa with Compound C under low glucose conditions significantly decreased the ATP levels and MMP, as well as liver kinase B1 and AMPK protein expression. Under low glucose conditions, sperm mainly produce ATP through mitochondrial OXPHOS to achieve high speed linear movement, inhibit ferroptosis through the LKB1/AMPK signaling pathway, and further maintain energy metabolism homeostasis.

Role of aquaporin 3 in reproductive performance of dairy goats after repeated estrus synchronization stimulation

This study explored the specific molecular mechanisms through which repeated estrus synchronization (ES) treatments reduce the reproductive performance of dairy goats. Ninety-six goats (n=24/group) were randomly assigned to two groups receiving ES treatments thrice every fortnight (3- equine chorionic gonadotropin [eCG] and 3-follicle stimulating hormone [FSH] groups) and two groups receiving one ES treatment (1-eCG and 1-FSH groups). ES treatments of 1- and 3-eCG goats were performed via the intravaginal insertion of a controlled internal drug release (CIDR) device containing 300 mg progesterone (P4), followed by 300 IU eCG injections 48 h before CIDR withdrawal. The 1- and 3-FSH goats received CIDR for 10 d, followed by 50 IU FSH and 100 μg PGF2α within 12 h of CIDR withdrawal. Ovaries of three goats in estrus from both groups were harvested for analysis. Subsequently, all the goats in estrus were artificially inseminated twice. Consequently, 3-eCG and 3-FSH goats showed a considerably reduced estrus rate and litter size than 1-eCG and 1-FSH goats. AQP3 mRNA and protein expression were significantly higher in the 3-eCG and 3-FSH groups than in the 1-eCG and 1-FSH groups. AQP3 overexpression led to cell apoptosis and decreased steroid hormone secretion ability of ovarian granulosa cells. Moreover, it resulted in a decrease in maturation and cleavage rates after parthenogenetic activation and in vitro fertilization, respectively. AQP3 gene was involved in reducing the reproductive performance of repeated ES-treated dairy goats. These findings provide a theoretical foundation for the effective use of reproductive hormones in breeding techniques for livestock.

Survival analysis of productive life in Florida dairy goats using a Cox proportional hazards model

Longevity is an economically important trait, since extending the functional life of a doe would allow us to keep the most productive females in the herd as long as possible, and this could result in the increased profitability of dairy farms. Thus, the objectives of this study were to determine the most important factors that influence the length of productive life (LPL) of female Florida goats and to estimate its genetic additive variance using a Cox proportional hazards model. The data consisted of 70,695 productive life records from 25,722 Florida females kidding between 2006 and 2020. A total of 19,495 does had completed their productive life while 6227 (24.2%) does had censored information. The pedigree contained information on 56,901 animals. The average censoring age and average failure age after first kidding for LPL were 36 and 47 months respectively. The model included, as time-independent effects, the age at first kidding and the interaction between herd, year and season of birth of the doe, and as time-dependent effects, the age at kidding, the interaction between herd, year and season of kidding, the within-herd class of milk production deviation, and the interaction between the lactation number and the stage of lactation. All fixed effects had a significant effect on LPL (p < 0.05). Does with older ages at the first kidding and an earlier age at kidding were at higher risk of being culled. A large difference among herds was observed in terms of culling risk, which highlighted the importance of adequate management practices. Also, high-producing does were less likely to be culled. The estimate of the additive genetic variance was 1.844 (in genetic standard deviation), with a heritability estimate of 0.58 ± 0.012. The results of this study are expected to contribute to the development of a genetic model for genetic evaluation of the length of the productive life of Spanish dairy goat breeds.

Effects of multimodal pain management strategies on acute physiological and behavioral response to cautery disbudding in neonatal goat kids

Dairy goat kids are commonly disbudded in the United States without pain relief. Our objective was to identify an efficient pain management strategy by monitoring changes in plasma biomarkers and behavior of disbudded goat kids. A total of 42 kids (5-18 d old at the time of disbudding) were randomly allocated to 1 of 7 treatments (n = 6/treatment): sham treatment; 0.05 mg/kg i.m. xylazine (X); 4 mg/kg subcutaneous buffered lidocaine (L); 1 mg/kg oral meloxicam (M); xylazine and lidocaine (XL); xylazine and meloxicam (XM); and xylazine, meloxicam, and lidocaine together (XML). Treatments were administered 20 min before disbudding. One trained individual, blinded to treatment, disbudded all kids; sham-treated kids were handled similarly except the iron was cold. Jugular blood samples (3 mL) were obtained before (-20, -10, and -1 min) and after (1, 15, and 30 min, and 1, 2, 4, 6, 12, 24, 36, 48 h) disbudding and analyzed for cortisol and prostaglandin E₂ (PGE₂). Mechanical nociceptive threshold (MNT) testing was performed at 4, 12, 24, and 48 h after disbudding, and kids were weighed daily until 2 d post-disbudding. Vocalizations, tail flicks, and struggle behavior during disbudding were recorded. Cameras were mounted over home pens; continuous and scan observations over 12 periods of 10 min each, in the 48 h after disbudding, captured frequency of locomotion and pain-specific behaviors. Repeated measures and linear mixed models assessed treatment effects on outcome measures during and after disbudding. Models accounted for sex, breed, and age as random effects, and Bonferroni adjustments accounted for multiple comparisons. At 15 min after disbudding, XML kids had lower plasma cortisol concentrations compared with L (50.0 ± 13.2 vs. 132.8 ± 13.6 mmol/L) and M kids (50.0 ± 13.2 vs. 145.4 ± 15.7 mmol/L). Cortisol was also lower in XML kids over the first hour after disbudding compared with L kids (43.4 ± 9 vs. 80.2 ± 9 mmol/L). Change from baseline PGE₂ was not affected by treatment. Behaviors observed during disbudding did not differ by treatment group. Treatment affected MNT such that M kids were more sensitive overall compared with sham kids (0.93 ± 0.11 kgf vs. 1.35 ± 0.12 kgf). None of the recorded post-disbudding behaviors were affected by treatment, but study activities did influence behavior over time, with kid activity levels declining in the first day after disbudding but largely recovering thereafter. We conclude that none of the drug combinations investigated here appeared to fully attenuate pain indicators during or after disbudding, but triple modality seems to have offered partial relief compared with some of the single-modality treatments.

Grape, Pomegranate, Olive, and Tomato By-Products Fed to Dairy Ruminants Improve Milk Fatty Acid Profile without Depressing Milk Production

The continuous increase in the cost of feeds and the need to improve the sustainability of animal production require the identification of alternative feeds, such as those derived from the agro-industrial sector, that can be effectively used for animal nutrition. Since these by-products (BP) are sources of bioactive substances, especially polyphenols, they may play an important role as a new resource for improving the nutritional value of animal-derived products, being effective in the modulation of the biohydrogenation process in the rumen, and, hence, in the composition of milk fatty acids (FA). The main objective of this work was to evaluate if the inclusion of BP in the diets of dairy ruminants, as a partial replacement of concentrates, could improve the nutritional quality of dairy products without having negative effects on animal production traits. To meet this goal, we summarized the effects of widespread agro-industrial by-products such as grape pomace or grape marc, pomegranate, olive cake, and tomato pomace on milk production, milk composition, and FA profile in dairy cows, sheep, and goats. The results evidenced that substitution of part of the ratio ingredients, mainly concentrates, in general, does not affect milk production and its main components, but at the highest tested doses, it can depress the yield within the range of 10-12%. However, the general positive effect on milk FA profile was evident by using almost all BP at different tested doses. The inclusion of these BP in the ration, from 5% up to 40% of dry matter (DM), did not depress milk yield, fat, or protein production, demonstrating positive features in terms of both economic and environmental sustainability and the reduction of human-animal competition for food. The general improvement of the nutritional quality of milk fat related to the inclusion of these BP in dairy ruminant diets is an important advantage for the commercial promotion of dairy products resulting from the recycling of agro-industrial by-products.

Effect of dietary biochanin A on lactation performance, antioxidant capacity, rumen fermentation and rumen microbiome of dairy goat

Biochanin A (BCA), an isoflavone phytoestrogen, is a secondary metabolite produced mainly in leguminous plants. The objective of this study was to evaluate the effect of BCA on lactation performance, nitrogen metabolism, and the health of dairy goat. Thirty mid-lactation Saanen dairy goats were divided into three groups randomly: control, 2 g/d BCA group, and 6 g/d BCA group. After 36 days of feeding, 30 dairy goats were transferred to individual metabolic cages. Subsequently, milk yield, feed intake, total feces, and urine excretion were recorded and samples were collected continuously for 3 days. Blood and ruminal fluid samples were collected over the subsequent 4 days. Milk yield, milk protein, fat content, and the feed conversion ratio of dairy goat were significantly increased by the BCA treatment. The levels of serum 17β-estradiol, growth hormone, insulin-like growth factor 1, glutathione peroxidase activity, and total antioxidant capacity were also increased significantly by BCA, indicating that BCA enhanced the antioxidant capacity of dairy goat. Amino acid degradation was significantly inhibited, while the ammonia nitrogen content was reduced significantly by BCA. Total volatile fatty acids was significantly increased by BCA supplementation. In addition, the relative abundance of Verrucomicrobiota was decreased significantly. However, the growth of nitrogen metabolism and cellulolytic bacteria was significantly increased under BCA treatment, including Prevotella sp., Treponema sp., Ruminococcus flavefaciens, and Ruminobacter amylophilus. In conclusion, supplementation with BCA improved the milk production performance, nitrogen metabolism, rumen fermentation and antioxidant capacity, and regulated the rumen microbiome of dairy goat.

Genome-wide association study for milk production and conformation traits in Canadian Alpine and Saanen dairy goats

Increasing the productivity of Canadian dairy goats is critical to the competitiveness of the sector; however, little is known about the underlying genetic architecture of economically important traits in these populations. Consequently, the objectives of this study were as follows: (1) to perform a single-step GWAS for milk production traits (milk, protein, and fat yields, and protein and fat percentages in first and later lactations) and conformation traits (body capacity, dairy character, feet and legs, fore udder, general appearance, rear udder, suspensory ligament, and teats) in the Canadian Alpine and Saanen breeds; and (2) to identify positional and functional candidate genes related to these traits. The data available for analysis included 305-d milk production records for 6,409 Alpine and 3,434 Saanen does in first lactation and 5,827 Alpine and 2,632 Saanen does in later lactations; as well as linear type conformation records for 5,158 Alpine and 2,342 Saanen does. Genotypes were available for 833 Alpine and 874 Saanen animals. Both single-breed and multiple-breed GWAS were performed using single-trait animal models. Positional and functional candidate genes were then identified in downstream analyses. The GWAS identified 189 unique SNP that were significant at the chromosomal level, corresponding to 271 unique positional candidate genes within 50 kb up- and downstream, across breeds and traits. This study provides evidence for the economic importance of several candidate genes (e.g., CSN1S1, CSN2, CSN1S2, CSN3, DGAT1, and ZNF16) in the Canadian Alpine and Saanen populations that have been previously reported in other dairy goat populations. Moreover, several novel positional and functional candidate genes (e.g., RPL8, DCK, and MOB1B) were also identified. Overall, the results of this study have provided greater insight into the genetic architecture of milk production and conformation traits in the Canadian Alpine and Saanen populations. Greater understanding of these traits will help to improve dairy goat breeding programs.

Alkaline Dilution Alters Sperm Motility in Dairy Goat by Affecting sAC/cAMP/PKA Pathway Activity

In dairy goat farming, increasing the female kid rate is beneficial to milk production and is, therefore, economically beneficial to farms. Our previous study demonstrated that alkaline incubation enriched the concentration of X-chromosome-bearing sperm; however, the mechanism by which pH affects the motility of X-chromosome-bearing sperm remains unclear. In this study, we explored this mechanism by incubating dairy goat sperm in alkaline dilutions, examining the pattern of changes in sperm internal pH and Ca2+ concentrations and investigating the role of the sAC/cAMP/PKA pathway in influencing sperm motility. The results showed that adding a calcium channel inhibitor during incubation resulted in a concentration-dependent decrease in the proportion of spermatozoa with forward motility, and the sperm sAC protein activity was positively correlated with the calcium ion concentration (r = 0.9972). The total motility activity, proportion of forward motility, and proportion of X-chromosome-bearing sperm decreased (p < 0.05) when cAMP/PKA protease activity was inhibited. Meanwhile, the enrichment of X-chromosome-bearing sperm by pH did not affect the sperm capacitation state. These results indicate that alkaline dilution incubation reduces Ca2+ entry into X-sperm and the motility was slowed down through the sAC/cAMP/PKA signaling pathway, providing a theoretical foundation for further optimization of the sex control method.

Whole-genome resequencing reveals genetic diversity and selection characteristics of dairy goat

The dairy goat is one of the earliest dairy livestock species, which plays an important role in the economic development, especially for developing countries. With the development of agricultural civilization, dairy goats have been widely distributed across the world. However, few studies have been conducted on the specific characteristics of dairy goat. In this study, we collected the whole-genome data of 89 goat individuals by sequencing 48 goats and employing 41 publicly available goats, including five dairy goat breeds (Saanen, Nubian, Alpine, Toggenburg, and Guanzhong dairy goat; n = 24, 15, 11, 6, 6), and three goat breeds (Guishan goat, Longlin goat, Yunshang Black goat; n = 6, 15, 6). Through compared the genomes of dairy goat and non-dairy goat to analyze genetic diversity and selection characteristics of dairy goat. The results show that the eight goats could be divided into three subgroups of European, African, and Chinese indigenous goat populations, and we also found that Australian Nubian, Toggenburg, and Australian Alpine had the highest linkage disequilibrium, the lowest level of nucleotide diversity, and a higher inbreeding coefficient, indicating that they were strongly artificially selected. In addition, we identified several candidate genes related to the specificity of dairy goat, particularly genes associated with milk production traits (GHR, DGAT2, ELF5, GLYCAM1, ACSBG2, ACSS2), reproduction traits (TSHR, TSHB, PTGS2, ESR2), immunity traits (JAK1, POU2F2, LRRC66). Our results provide not only insights into the evolutionary history and breed characteristics of dairy goat, but also valuable information for the implementation and improvement of dairy goat cross breeding program.

Effect of dietary Conocarpus erectus leaves and branches on milk yield, quality, antioxidant activity and fatty acid profile, and blood parameters of Najdi dairy goats

To investigate the effect of Conocarpus erectus tree leaves and branches as a partial replacement of forage on milk yield and components, blood and rumen parameters of goats, 16 Najdi goats were used in a completely randomized design with 2 treatments (CON, without C. erectus; CE, contains C. erectus). The basic ratio consisted of 60% concentrate and 40% forage. In treatment CE, 22.5% of the forage (alfalfa hay and wheat straw) was replaced with C. erectus leaves and branches. The lowest amount of dry matter intake and digestibility were observed in the treatment CE (P < 0.05). The amount of milk production significantly increased (P = 0.01) in the treatment CE. The total count did not differ between treatments, but the highest amount of Lactobacillus spp. (P = 0.01) and the lowest amount of mold (P = 0.01) were observed in the treatment CE. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity decreased on days 15 (P = 0.02) and 31 (P = 0.01) of the experiment in treatment CE. The highest amount of short-, medium-, and long-chain fatty acids and also conjugated fatty acids were observed in the treatment CE (P < 0.05). Also, the concentration of fatty acids C16:0 and C18:0 was lower in the treatment CE (P < 0.05). The lowest amount of triglycerides, blood urea nitrogen, cholesterol, low-density lipoprotein, high-density lipoproteins, serum glutamic pyruvic transaminase, and serum glutamic oxaloacetic transaminase were observed in the treatment CE (P < 0.05). Ruminal pH and ammonia-N concentration were not affected by experimental treatment (P > 0.05). According to the results, the use of C. erectus leads to improved milk production and fatty acid profile, antioxidant activity, and microbial load.

Postbiotic yeast fermentation product supplementation to lactating goats increases the efficiency of milk production by enhancing fiber digestibility and ruminal propionate, and reduces energy losses in methane

Although in vitro data with mixed ruminal fluid demonstrated positive effects of posbiotic diet (POS) from lactobacilli on measures of fermentation and microbial profiles, there is a paucity of in vivo data with lactating ruminants. The aim of the study was to evaluate the effects of incorporating POS into diets of lactating goats on energy (E) partitioning, carbon (C) and nitrogen (N) balance, and performance. Ten late-lactation Murciano-Granadina goats were used in a crossover design with 26-d periods. Goats in the control diet (CON) were fed daily at the rate of 1 kg alfalfa hay and 1.5 kg concentrate, and the treatment group (POS) was fed CON with the addition of 3.75 g/d of Probisan Ruminants (PENTABIOL S.L., Navarra, Spain). No differences in DMI were detected. However, ruminal fluid propionate and apparent total tract digestibilities of NDF and ADF were greater (18%, 4.7%, and 5.2%, respectively; P < 0.05) in POS compared with the CON diet. Daily partitioning of E to milk and efficiency of ME intake for milk production greater (11% and 3.0%, respectively; P < 0.05) in POS compared with CON. The nonprotein RQ was greater in POS compared with CON due to greater (P < 0.05) oxidation of carbohydrate (213 vs. 115 kJ/kg of BW0.75 per day) compared with fat (362 vs. 486 kJ/kg of BW0.75 per day). Although no differences were found in C balance, goats in POS had lower (P < 0.05) amounts of C in CH4 (1.1 vs. 1.3 g/kg BW0.75 per day) compared with CON. There were no differences in N intake or N in feces or urine, but N in milk was greater (P < 0.05) in POS compared with the CON diet (0.8 vs. 0.7 g/kg BW0.75 per day). Yield of fat-corrected milk (FCM) (3.20 vs. 2.72 kg/d; P < 0.05) and concentration of true protein (3.4 vs. 3.3 kg/d; P < 0.05) and lactose (4.7 vs. 4.5 kg/d; P < 0.05) were greater in POS compared with CON. These responses were accompanied by lower (P < 0.05) urea (12.3 vs. 16.6 mM/L) and ammonia-N (6.6 vs. 8.8 mg/L) without changes in fat concentration (6.1% vs. 6.0%; P > 0.05) in POS compared with the CON diet. Daily amount of CH4 emission did not differ P > 0.05 between diets. However, when expressed relative to unit of edible product, feeding POS reduced (P < 0.05) the amount of CH4 by 46 g/kg of milk fat, 97 g/kg of milk protein, and 3 g/kg of milk compared with CON. Overall, data indicated that feeding a postbiotic in late-lactation increased energy efficiency for milk production partly by reducing CH4 emission.

Genome-wide analysis for the melatonin trait associated genes and SNPs in dairy goat (Capra hircus) as the molecular breeding markers

Previous studies have reported that the endogenous melatonin level is positively associated with the quality and yield of milk of cows. In the current study, a total of 34,921 SNPs involving 1,177 genes were identified in dairy goats by using the whole genome resequencing bulked segregant analysis (BSA) analysis. These SNPs have been used to match the melatonin levels of the dairy goats. Among them, 3 SNPs has been identified to significantly correlate with melatonin levels. These 3 SNPs include CC genotype 147316, GG genotype 147379 and CC genotype 1389193 which all locate in the exon regions of ASMT and MT2 genes. Dairy goats with these SNPs have approximately 5-fold-higher melatonin levels in milk and serum than the average melatonin level detected in the current goat population. If the melatonin level impacts the milk production in goats as in cows, the results strongly suggest that these 3 SNPs can serve as the molecular markers to select the goats having the improved milk quality and yield. This is a goal of our future study.

Combined Transcriptomic and Proteomic of Corynebacterium pseudotuberculosis Infection in the Spleen of Dairy Goats

Corynebacterium pseudotuberculosis (C. pseudotuberculosis) is a zoonotic chronic infectious disease. It mainly occurs in dairy goats reared in herds, and once it invades the dairy goats, it is difficult to completely remove it, causing great harm to the development of the sheep industry. This study mainly was based on TMT-based quantitative proteomics and RNA-seq methods to measure the spleen samples of infected dairy goats at different time periods. Nine four-month-old dairy goats were divided into three groups, with three goats in each group. The dairy goats in the first group (NC group) were inoculated with 1.0 mL of sterilized normal saline subcutaneously, and the second (72 h group) and third groups (144 h group) were inoculated with 1.0 mL of 1 × 10⁷ cfu/mL bacterial solution subcutaneously in the neck. Significant changes in the protein and mRNA expression were observed in different infection and control groups. In the 72 h group, 85 genes with differential genes and proteins were up-regulated and 91 genes were down-regulated in this study. In the 144 h group, 38 genes with differential genes and proteins were up-regulated and 51 genes were down-regulated. It was found that 21 differentially expressed genes and proteins were co-up-regulated in the two groups. There were 20 differentially expressed genes and proteins which were co-down-regulated in both groups. The 72 h group were mainly enriched in protein processing in the endoplasmic reticulum, lysosome, amino sugar and nucleotide sugar metabolism and the estrogen signaling pathway. In the 144 h group, they were protein processing in the endoplasmic reticulum pathway which was enriched by mRNA-proteins pairs co-upregulated by the five pairs. The combined transcriptomic and proteomic analyses were performed to provide insights into the effects of C. pseudotuberculosis through several regulatory features and pathways. We found that in the early stage of infection (72 h), the co-upregulated gene-protein pairs were enriched in multiple pathways, which jointly defended against a bacterial invasion. However, in the later stages of infection (144 h), when the disease stabilizes, a few co-upregulated gene-protein pairs played a role in protein processing in the endoplasmic reticulum pathway. In addition, the mRNA and protein expressions of dairy goats infected with the bacteria at different periods of time indicated the adaptability of dairy goats to the bacteria. At the same time, it guides us to carry out a corresponding treatment and feeding management for dairy goats according to different periods of time.

A cross-sectional survey of risk factors for the presence of Coxiella burnetii in Australian commercial dairy goat farms

The largest Australian farm‐based outbreak of Q fever originated from a dairy goat herd. We surveyed commercial dairy goat farms across Australia by testing bulk tank milk (BTM) samples using a commercial indirect enzyme‐linked immunosorbent assay and two quantitative polymerase chain reactions (PCRs). Of the 66 commercial dairy goat herds on record, managers from 61 herds were contacted and 49 provided BTM samples. Five of the surveyed herds were positive on at least one of the diagnostic tests, thus herd‐level apparent prevalence was 10% (95% confidence interval [CI] 4 to 22). True prevalence was estimated to be 3% (95% credible interval: 0 to 18). Herd managers completed a questionnaire on herd management, biosecurity and hygiene practices and risk factors were investigated using multivariable logistic regression. Herds with >900 milking does (the upper quartile) were more likely to be Coxiella burnetii positive (odds ratio = 6.75; 95% CI 1.65 to 27.7) compared with farms with ≤900 milking does. The odds of BTM positivity increased by a factor of 2.53 (95% CI 1.51 to 4.22) for each order of magnitude increase in the number of goats per acre. C. burnetii was not detected in samples from the majority of the Australian dairy goat herds suggesting there is an opportunity to protect the industry and contain this disease with strengthened biosecurity practices. Intensification appeared associated with an increased risk of positivity. Further investigation is required to discriminate the practices associated with an increased risk of introduction to disease‐free herds, from practices associated with maintenance of C. burnetii infection in infected dairy goat herds.

Characterization of Bioactive Sialyl Oligosaccharides Separated from Colostrum of Indonesia Dairy Goat

The bioactive functions of oligosaccharides from human milk have been reported by many studies. Many of oligosaccharides isolated from colostrum and/or milk of dairy animals have been reported to have similar chemical structures with those in human colostrum and/or milk. It has been proved by several studies that the oligosaccharides with similar chemical structure shared common bioactivities. Among domesticated dairy animals, bovine/cattle, caprine/goat, and ovine/sheep are the most commonly used species to isolate oligosaccharides from their colostrum and/or milk. Several studies on the oligosaccharides from goat colostrum and milk have revealed similar properties to that of human milk and possess the highest content of sialyl oligosaccharides (SOS) as compared to other ruminants. Indonesia ranks first in Association of Southeast Asian Nations (ASEAN) for goat milk production. Therefore, goat milk is the second most consumed milk in the country. The most reared dairy goat breed in Indonesia is Etawah Grade. However, oligosaccharides from Indonesia dairy animals including goat, have not been characterized. This is the first study to characterize oligosaccharides from Indonesia dairy animals. The present study was aimed to isolate and characterize oligosaccharides, specifically SOS from the colostrum of Etawah Grade goats by using proton/1H-nuclear magnetic resonance. The SOS successfully characterized in this study were: Neu5Ac(α2-3)Gal(β1-4)Glc (3'-N-acetylneuraminyllactose), Neu5Ac(α2-6)Gal(β1-4)Glc (6'-N-acetylneuraminyllactose), Neu5Gc(α2-3)Gal(β1-4)Glc (3'-N-glycolylneuraminyllactose), Neu5Gc(α2-6)Gal(β1-4)Glc (6'-N-glycolylneuraminyllactose), Neu5Ac(α2-6)Gal(β1-4) GlcNAc (6'-N-acetylneuraminyllactosamine) and Neu5Gc(α2-6)Gal(β1-4)GlcNAc (6'-N-glycolylneuraminyllactosamine). This finding shows that Etawah Grade, as a local dairy goat breed in Indonesia, is having significant potential to be natural source of oligosaccharides that can be utilized in the future food and pharmaceutical industries.

Effect of Non-Genetic Factors on Reproduction of Extensive versus Intensive Florida Dairy Goats

The main objective of this study was to evaluate the effect of the production system and other environmental/phenotype factors on age at first kidding (AFK), kidding interval (KI) and prolificacy of 19,772 Florida goats reared between 2000 and 2019 on 49 dairy farms (38 farms intensively managed and 11 extensively managed with grazing). AFK was lower on intensive (490.2 ± 0.9 days; n = 13,345) than on extensive farms (511.7 ± 2.5 days; n = 2357; p < 0.001), and highest during the spring season (533.9 ± 2.7 days; n = 1932; p < 0.001) in both production systems. The average KI was 355.7 ± 0.4 days, mainly varying according to dry period, kidding season and lactation number and kidding type (p < 0.01). A significant interaction between production system, kidding season and dry period was observed with the highest AFK on intensive farms during spring and summer for goats presenting a dry period of up to six months. The overall prolificacy (1.64 ± 0.01) increased in recent years in both systems, and it was affected by the production system, but with different patterns; so, the highest prolificacy of primiparous and multiparous goats was observed on extensive and intensive farms, respectively. Besides that, the prolificacy and other reproductive parameters, such as AFK, significantly increased in the last decade, which could be related to management improvements. Besides that, the existence of inter-annual variations should be considered to compare data between farms and years, and to establish the farms’ objectives according to their production systems and production goals.

Evaluation of the health status of mammary glands and compositional changes in udder-half milk obtained from dairy goats for milk quality management

This study evaluated the health status of the mammary glands and milk composition of dairy goats. The California mastitis test (CMT) score, somatic cell counts (SCCs), somatic cell type, electrical conductivity (EC), N-acetyl-β-d-glucosaminidase (NAGase) activity, mastitis-causing pathogens, and milk composition in 121 udder-half milk samples from 62 crossbreed goats (1-3 years old) at 23-45 days postpartum were compared in four categories with SCCs of <200 × 10³ , <300 × 10³ , 301-1000 × 10³ , and >1010 × 10³  cells/ml. The SCC, CMT score, EC, and NAGase activity were significantly lower (p < 0.05) in udder-half milk with SCCs of <200 × 10³ and <300 × 10³  cells/ml than those in milk with SCCs of 301-1000 × 10³ and >1010 × 10³  cells/ml. The protein, lactose/ash, and solids-not-fat (SNF) in milk with an SCC of <300 × 10³  cells/ml were similar to the previously reported values. The proportion of polymorphonuclear neutrophils was significantly higher (p < 0.05) in milk with SCCs of 301-1000 and >1010 × 10³  cells/ml than in milk with an SCC of <300 × 10³  cells/ml. Assessing mammary gland health and milk composition based on categorization of udder-half milk by SCC may be useful for milk quality control on goat farms.

Effect of MiR-100-5p on proliferation and apoptosis of goat endometrial stromal cell in vitro and embryo implantation in vivo

The growth of endometrial stromal cells (ESCs) at implantation sites may be a potential factor affecting the success rate of embryo implantation. Incremental proofs demonstrated that ncRNAs (e.g. miRNAs, lncRNAs and circRNAs) were involved in various biological procedures, including proliferation and apoptosis. In this study, the role of miR‐100‐5p on proliferation and apoptosis of goat ESCs in vitro and embryo implantation in vivo was determined. The mRNA expression of miR‐100‐5p was significantly inhibited in the receptive phase (RE) rather than in the pre‐receptive phase (PE). Overexpression of miR‐100‐5p suppressed ESCs proliferation and induced apoptosis. The molecular target of MiR‐100‐5p, HOXA1, was confirmed by 3′‐UTR assays. Meanwhile, the product of HOXA1 mRNA RT‐PCR increased in the RE more than that in the PE. The HOXA1‐siRNA exerted significant negative effects on growth arrest. Instead, incubation of ESCs with miR‐100‐5p inhibitor or overexpressed HOXA1 promoted the cell proliferation. In addition, Circ‐9110 which acted as a sponge for miR‐100‐5p reversed the relevant biological effects of miR‐100‐5p. The intrinsic apoptosis pathway was suppressed in ESCs, revealing a crosstalk between Circ‐9110/miR‐100‐5p/HOXA1 axis, PI3K/AKT/mTOR, and ERK1/2 pathways. To further evaluate the progress in study on embryo implantation regulating mechanism of miR‐100‐5p in vivo, the pinopodes of two phases were observed and analysed, suggesting that, as similar as in situ, miR‐100‐5p was involved in significantly regulating embryo implantation in vivo. Mechanistically, miR‐100‐5p performed its embryo implantation function through regulation of PI3K/AKT/mTOR and ERK1/2 pathways by targeting Circ‐9110/miR‐100‐5p/HOXA1 axis in vivo.

Increasing serotonin concentrations alter calcium metabolism in periparturient dairy goats

Due to the large amounts of calcium transferred to milk from mammary glands, periparturient dairy goats face challenges with calcium metabolism disorder and hypocalcemia. Serotonin (5-hydroxytryptamine, 5-HT), the product of 5-hydroxy-l-tryptophan (5-HTP) catalyzed by tryptophan hydroxylase 1, is a multifunctional monoamine thought to be a homeostatic regulator of the animal. The objective of the current study was to investigate the effects and underlying mechanisms of intramuscular 5-HTP injections on calcium homeostasis in the goat mammary glands. In the in vivo experiment, 30 multiparous Guanzhong dairy goats were randomly assigned to 2 groups, one group was injected with 5-HTP intramuscularly and the other group was injected with normal saline. From the first 10 d of the expected date for delivery, 5-HTP or saline was injected into goats through the shoulder muscle every morning before feeding, with a dose of 1 mg/kg per body weight. In the in vitro experiment, goat mammary epithelial cells (GMEC) were treated with 100 μM 5-HT for the evaluation of 5-HT in calcium transportation. The results demonstrated that 5-HTP treatment had no effect on the basic composition of colostrum (P > 0.05) but increased the serum 5-HT concentrations on days -5, -4, -3, and 5 relative to parturition (P < 0.05). The 5-HTP injection group had greater serum calcium concentration on day 4 and greater serum parathyroid hormone-related protein (PTHrP) on days -5, -4, -1, 3, 4, and 5 compared with the saline injection group (P < 0.05). It was further confirmed that 5-HT could increase intracellular calcium levels by increasing PTHrP and decreasing plasma membrane Ca2+-ATPases1 (PMCA1) in GMEC (P < 0.05). In conclusion, 5-HTP treatment in multiparous goats during the transition period from pregnancy to lactation is a feasible way to protect goats from calcium metabolism disorder.

Single-step genomic evaluation of milk production traits in Canadian Alpine and Saanen dairy goats

Genomic evaluations are routine in most plant and livestock breeding programs but are used infrequently in dairy goat breeding schemes. In this context, the purpose of this study was to investigate the use of the single-step genomic BLUP method for predicting genomic breeding values for milk production traits (milk, protein, and fat yields; protein and fat percentages) in Canadian Alpine and Saanen dairy goats. There were 6,409 and 12,236 Alpine records and 3,434 and 5,008 Saanen records for each trait in first and later lactations, respectively, and a total of 1,707 genotyped animals (833 Alpine and 874 Saanen). Two validation approaches were used, forward validation (i.e., animals born after 2013 with an average estimated breeding value accuracy from the full data set ≥0.50) and forward cross-validation (i.e., subsets of all animals included in the forward validation were used in successive replications). The forward cross-validation approach resulted in similar validation accuracies (0.55 to 0.66 versus 0.54 to 0.61) and biases (-0.01 to -0.07 versus -0.03 to 0.11) to the forward validation when averaged across traits. Additionally, both single and multiple-breed analyses were compared, and similar average accuracies and biases were observed across traits. However, there was a small gain in accuracy from the use of multiple-breed models for the Saanen breed. A small gain in validation accuracy for genomically enhanced estimated breeding values (GEBV) relative to pedigree-based estimated breeding values (EBV) was observed across traits for the Alpine breed, but not for the Saanen breed, possibly due to limitations in the validation design, heritability of the traits evaluated, and size of the training populations. Trait-specific gains in theoretical accuracy of GEBV relative to EBV for the validation animals ranged from 17 to 31% in Alpine and 35 to 55% in Saanen, using the cross-validation approach. The GEBV predicted from the full data set were 12 to 16% more accurate than EBV for genotyped animals, but no gains were observed for nongenotyped animals. The largest gains were found for does without lactation records (35-41%) and bucks without daughter records (46-54%), and consequently, the implementation of genomic selection in the Canadian dairy goat population would be expected to increase selection accuracy for young breeding candidates. Overall, this study represents the first step toward implementation of genomic selection in Canadian dairy goat populations.

Palm Kernel Cake in Diets for Lactating Goats: Qualitative Aspects of Milk and Cheese

Simple Summary

Feedlotting lactating goats is a strategy to improve their productivity and the quality of their milk and dairy products. However, feedlotting is associated with increases in production costs, due mainly to the concentrate component of the diet. The use of agro-industrial byproducts allows the reduction of feed costs by replacing costly ingredients, as the former are more easily accessible. We tested the dietary inclusion of palm kernel cake (PKC), a byproduct of the biofuel industry, at the levels of 0, 80, 160 and 240 g kg⁻¹, to evaluate its impact on the qualitative aspects of milk and cheese. The inclusion of up to 80 g kg⁻¹ PKC is recommended for the diet of goats whose milk will be used in the production of Minas Frescal cheese.

Abstract

We investigated the effect of including palm kernel cake (PKC) at the levels of 0, 80, 160 and 240 g kg⁻¹ in the diet of lactating goats on the quality and sensory parameters of Minas Frescal cheese. Twelve goats were used in a triple 4 × 4 Latin square design. The dietary addition of PKC was associated with a reduction in moisture (p = 0.004), which compromised the cheese yield (p = 0.030). The ether extract content showed a quadratic response. There was a decrease in caproic (p = 0.014), caprylic (p = 0.011), capric (p = 0.003) and palmitic (p = 0.049) acids and an increase in lauric (p = 0.012) and myristic (p = 0.02) acids. Monounsaturated fatty acids increased (p = 0.008), whereas the ratio of polyunsaturated to saturated fatty acids (p = 0.022) and thrombogenicity index (p = 0.023) decreased. Principal component analysis indicated that control treatment and the treatment with 80 g kg⁻¹ PKC were the most acceptable to the cheese tasters. The use of palm kernel cake is a good alternative for lactating goats when added to the diet at levels up to 80 g kg⁻¹.

Changes in histology, protein expression, and autophagy in dairy goat testes during nonbreeding season†

Seasonal reproduction contributes to increased chances of offspring survival in some animals. Dairy goats are seasonal breeding mammals. In this study, adult male Guanzhong dairy goats (10-12 months old) were used. Testis size, semen quality, hormone level, apoptosis of germ cells, and autophagy of Sertoli cells were analyzed in dairy goats during the breeding (October) and nonbreeding (April) seasons. We found that, during the nonbreeding season for dairy goats, semen quality, follicle-stimulating hormone (FSH) levels, and testosterone levels were reduced, and the number of apoptotic germ cells increased. The proliferation with decrease activity of germ cells in dairy goat during the nonbreeding season was significantly affected. However, the testis size did not change seasonally. Interestingly, Sertoli cell autophagy was more active during the nonbreeding season. The expression levels of FSH receptor, wilms tumor 1, androgen binding protein, glial cell derived neurotrophic factor, and stem cell factor decreased in dairy goats during the nonbreeding season. In summary, our results indicate that spermatogenesis in dairy goats during the nonbreeding season was not completely arrested. In addition, germ cell apoptosis and the morphology of Sertoli cells considerably changed in dairy goats during the nonbreeding season. Sertoli cell autophagy is involved in the seasonal regulation of spermatogenesis in dairy goats. These findings provide key insights into the fertility and spermatogenesis of seasonal breeding animals.

Effects of Diluent pH on Enrichment and Performance of Dairy Goat X/Y Sperm

In this paper, on the basis of the differences in the hydrogen ion concentration (pH) of the diluent dairy goat semen on X/Y sperm motility, an X/Y sperm enrichment study was conducted to establish a simple and effective method for gender control in dairy goats. Dairy goat semen was diluted using different pH dilutions and was incubated. Then, the X/Y sperm ratio in the isolated upper sperm was determined using the double TaqMan qPCR method. The internal pH change pattern of sperm cells at different pH dilutions was measured using BCECF-AM probe, and the functional parameters of the isolated sperm were tested with the corresponding kit. Next, an in vitro fertilization test was conducted using isolated spermatozoa and oocytes to determine their fertilization rates, the percentages of female embryos, and the expression of genes related to developing potentially fertilized embryos. Results showed that the percentages of the X sperm cells in the upper sperm layer were 67.24% ± 2.61% at sperm dilution pH of 6.2 and 30.45% ± 1.03% at sperm dilution pH of 7.4, which was significantly different from 52.35% ± 1.72% of the control group (pH 6.8) (P < 0.01). Results also showed that there is a relationship between the external pHo and internal pHi of sperm cells. Furthermore, the percentages of female embryos after the in vitro fertilization of the isolated upper sperm with mature oocytes at pH 6.2 and 7.4 were 66.67% ± 0.05 and 29.73% ± 0.04%, respectively, compared with 48.57% ± 0.02% in the control group (pH 6.8). Highly significant differences occurred between groups (P < 0.01). Additionally, no significant difference was observed during the expression of genes related to embryonic development between the blastocysts formed from sperm isolated by changing the pH of the diluent and the control sperm (P > 0.05). Therefore, this study successfully established a simple and effective method for enriched X/Y sperms from dairy goats, which is important for regulating the desired sex progeny during dairy goat breeding and for guiding dairy goat production.

Lying Behaviour in Dairy Goats: Effects of a New Automated Feeding System Assessed by Accelerometer Technology

Simple Summary

Goat farming is becoming more important in Germany and as dehorning is forbidden, it is necessary to facilitate animal welfare among horned and mixed-horned herds. In this study an optimized automatic concentrated feeding system was installed in a mixed-horned herd and lying behaviour was detected by accelerometer technology. Results show a seasonal progression of lying behaviour in dairy goats and an adjustment of behavioural differences between horned and hornless goats with the new feeding system.

Abstract

The aim of this study was to evaluate lying behaviour in dairy goats before and after installation of an optimized automatic concentrated feeding system (AFS). A mixed-horned herd of Bunte Deutsche Edelziege was used. As many agonistic interactions between goats happen at the feeding place, a new automated feeding system was installed to better fulfil the needs of horned goats. Lying behaviour is an indicator to ascertain animal welfare of ruminants. In order to measure lying behaviour accelerometer technology was used and verified by video analyses. The results show an agreement of 99.62–99.93% per lying time by comparing accelerometers to video data. Over all goats, a mean ± SD lying time (LT) of 11.78 ± 1.47 h/d, a mean ± SD lying bout duration (LBD) of 0.51 ± 0.10 h/bout and a mean ± SD frequency of lying bouts (FLB) of 24.35 ± 5.57 were found. Lying behaviour follows a seasonal progression with significant lowest LBD and highest FLB in summer. With the old AFS significant differences in LBD and FLB were detected between horned and hornless goats, but with the new AFS results were adjusted. Findings suggest that changes in feeding management do not affect the general seasonal progression of lying behaviour but can affect the behavioural differences between horned and hornless dairy goats.

Influence of Housing and Management on Claw Health in Swiss Dairy Goats

Simple Summary

Swiss dairy goats are commonly housed on deep littler, at least during the winter season. Due to the lack of horn wear, their claws often show overgrown wall horn. However, little is known about the impact of wall horn overgrowth on claw health and whether wall horn overgrowth impairs the goats’ locomotion behavior. Data was collected on 28 Swiss commercial dairy goat farms during autumn and spring. It was shown that severe wall horn overgrowth dominated during the indoor housing period and was associated with an increase in the proportion of claws with sole hemorrhages. Furthermore, wall horn overgrowth did not seem to have an effect on the goats’ locomotion behavior. The results of this study underline the importance of regular and careful claw trimming.

Abstract

Due to a rising demand for goat milk and goat milk products worldwide, it is likely that dairy goat production will be intensified in the future, with larger herds per farm. In Switzerland, as in many other countries with intensive farming systems, dairy goats are typically housed on deep litter, with little access to hard abrasive surfaces. Such housing conditions will result in wall horn overgrowth. The aim of this study was to gain profound knowledge on the occurrence of overgrown wall horn, its impact on claw health and locomotor behavior, and possible adverse effects on animal welfare. Additionally, housing and management factors that may contribute to non-physiological claw conditions were evaluated. To compare claw conditions after the summer grazing period and the winter indoor housing period, data were collected on 28 Swiss dairy goat farms in autumn and spring (621 goats in total). Claw lesions were recorded with the help of a “claw card” documenting each claw. Furthermore, pictures were taken of each claw to determine the severity of wall horn overgrowth. Locomotion behavior (activity, lying time and lying bouts) was recorded with three-dimensional accelerometers fixed to the goats’ hind legs. In autumn, 66.7% of the examined claws showed moderate overgrowth, 32.4% severe overgrowth and 0.9% no overgrowth. In spring, 47.4% of the examined claws were affected with moderate overgrowth, 52.6% with severe overgrowth and 0.0% with no overgrowth. Horn separation (48.1% of examined claws) and sole hemorrhages (16.0% of examined claws) were the most frequent lesions. In goats with severely overgrown claws, the risk of developing sole hemorrhages was doubled compared with moderate overgrowth. The occurrence rate of horn separation was lower if the trimmer had attended a special skills training course (p < 0.001). Furthermore, locomotor activity (p < 0.01) and the number of lying bouts per day (p < 0.01) were higher in spring than autumn. Neither the goats’ activity nor the number of lying bouts per day differed before and after claw trimming. Finally, season and trimming were not associated with the goats’ total lying time. A certain extent of wall horn overgrowth in dairy goat claws cannot be avoided under the housing conditions typical for Swiss farms. Severe wall horn overgrowth is associated with an increase in the proportion of claws with sole hemorrhages. Therefore, regular and careful functional claw trimming, taking the housing situation (deep bedding, access to pasture, grazing on alpine pasture) into account, should be promoted.

Metabolizable Protein: 2. Requirements for Maintenance in Growing Saanen Goats

This study aimed to estimate the protein requirements for the maintenance of growing Saanen goats of different sexes from 5 to 45 kg of body weight (BW) using two methods and applying a meta-analysis. For this purpose, two datasets were used. One dataset was used to evaluate the effects of sex on the protein requirements for maintenance using the comparative slaughter technique. This dataset was composed of 185 individual records (80 intact males, 62 castrated males, and 43 females) from six studies. The other dataset was used to evaluate the effects of sex on the protein requirements for maintenance using the N balance method. This dataset was composed of 136 individual records (59 intact males, 43 castrated males, and 34 females) from six studies. All studies applied an experimental design that provided different levels of N intake and different levels of N retention, allowing the development of regression equations to predict the net protein requirement for maintenance (NPM) and the metabolizable protein (MP) requirements for maintenance (MPM) in Saanen goats. The efficiency of MP use for maintenance (kPM) was computed as NPM/MPM. The efficiency of MP use for gain (kPG) was calculated using the equation of daily protein retained against daily MP intake above maintenance. A meta-analysis was applied using the MIXED procedure of SAS, in which sex was considered a fixed effect, and blocks nested in the studies and goat sex were considered as random effects. The NPM did not differ between sexes, irrespective of the approach used. The daily NPM estimated was 1.23 g/kg0.75 BW when using the comparative slaughter technique, while it was 3.18 g/kg0.75 BW when using the N balance technique for growing Saanen goats. The MPM estimated was 3.8 g/kg0.75 BW, the kPM was 0.33, and the kPG was 0.52. We observed that the NPM when using the comparative slaughter technique in growing Saanen goats is lower than that recommended by the current small ruminant feeding systems; on the other hand, the MPM was similar to previous reports by the feeding systems. Sex did not affect the protein requirements for maintenance and the efficiencies of use of metabolizable protein.

A Metagenomic Insight Into the Hindgut Microbiota and Their Metabolites for Dairy Goats Fed Different Rumen Degradable Starch

High starch diets have been proven to increase the risk of hindgut acidosis in high-yielding dairy animals. As an effective measurement of dietary carbohydrate for ruminants, studies on rumen degradable starch (RDS) and the effects on the gut microbiota diversity of carbohydrate-active enzymes (CAZymes), and Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthology functional categories are helpful to understand the mechanisms between gut microbiota and carbohydrate metabolism in dairy goats. A total of 18 lactating goats (45.8 ± 1.54 kg) were randomly divided equally into three dietary treatments with low dietary RDS concentrations of 20.52% (LRDS), medium RDS of 22.15% (MRDS), and high RDS of 24.88% (HRDS) on a DM basis for 5 weeks. Compared with the LRDS and MRDS groups, HRDS increased acetate molar proportion in the cecum. For the HRDS group, the abundance of family Ruminococcaceae and genus Ruminococcaceae UCG-010 were significantly increased in the cecum. For the LRDS group, the butyrate molar proportion and the abundance of butyrate producer family Bacteroidale_S24-7, family Lachnospiraceae, and genus Bacteroidale_S24-7_group were significantly increased in the cecum. Based on the BugBase phenotypic prediction, the microbial oxidative stress tolerant and decreased potentially pathogenic in the LRDS group were increased in the cecum compared with the HRDS group. A metagenomic study on cecal bacteria revealed that dietary RDS level could affect carbohydrate metabolism by increasing the glycoside hydrolase 95 (GH95) family and cellulase enzyme (EC 3.2.1.4) in the HRDS group; increasing the GH13_20 family and isoamylase enzyme (EC 3.2.1.68) in the LRDS group. PROBIO probiotics database showed the relative gene abundance of cecal probiotics significantly decreased in the HRDS group. Furthermore, goats fed the HRDS diet had a lower protein expression of Muc2, and greater expression RNA of interleukin-1β and secretory immunoglobulin A in cecal mucosa than did goats fed the LRDS diet. Combined with the information from previous results from rumen, dietary RDS level altered the degradation position of carbohydrates in the gastrointestinal (GI) tract and increased the relative abundance of gene encoded enzymes degrading cellulose in the HRDS group in the cecum of dairy goats. This study revealed that the HRDS diet could bring disturbances to the microbial communities network containing taxa of the Lachnospiraceae and Ruminococcaceae and damage the mucus layer and inflammation in the cecum of dairy goats.

Surrogate Indexes of Insulin Resistance in Dairy Goats: Transitional Variation in Subclinical Hyperketonemia

Background: Dairy goats are highly susceptible to subclinical hyperketonemia (SCHK) during the transition period. This study aimed to compare the variation in metabolic parameters and surrogate indexes of insulin resistance (sIR) between goats with SCHK and clinically healthy (HEAL) goats during the transition period. Methods: Twenty Guanzhong dairy goats were assorted to HEAL (n = 10) and SCHK (n = 10) groups according to the blood β-hydroxybutyrate (BHBA) concentrations. The blood samples were taken from the jugular vein of each goat at −3, −2, −1, 0 (partum), +1, +2, and +3 weeks relative to kidding to analyses GLU and INS. The sIR was calculated from blood metabolic parameters. Results: Compared with the HEAL goats, the insulin concentrations were significantly higher in SCHK goats during the first three weeks postpartum. The QUICKI, revised QUICKI (RQUICKI), and RQUICKI_BHBA were significantly lower in goats with SCHK at 1 week postpartum, while the homeostasis model assessment-IR (HOMA-IR) was significantly higher. Conclusion: Goats with SCHK made more efforts through elevated insulin levels at early lactation than HEAL goats, thereby maintaining the normal glucose concentrations.

Prevalence of Mastitis and Antibiotic Resistance of Bacterial Isolates from CMT Positive Milk Samples Obtained from Dairy Cows, Camels, and Goats in Two Pastoral Districts in Southern Ethiopia

Simple Summary

A study was carried out from August 2017 to February 2018 on lactating dairy cows, one-humped dromedary camels, and goats to determine mastitis in the Bule Hora and Dugda Dawa districts of in Southern Ethiopia. Milk samples from 564 udder quarters and udder halves from 171 animals consisting of 60 dairy cows, 51 camels, and 60 goats were tested for mastitis. Sixty-four positive udder milk samples were cultured, and bacterial mastitis pathogens were isolated and identified. The antibiotic resistance of bacterial isolates from milk with mastitis was tested against nine antimicrobials commonly used in the study area. Cow-level prevalence of mastitis in dairy cows, camels, and goats was 33.3%, 26.3%, and 25%, respectively. The quarter-level prevalence of mastitis in cows, camels and goats was 17.6%, 14.5%, and 20%, respectively. In cattle, the prevalence was significantly higher in Dugda Dawa than in Bule Hora. Major bacterial isolates were coagulase-negative Staphylococcus species (39.1%), S. aureus (17.2%), S. hyicus (14.1%), and S. intermedius and Escherichia coli (9.4% each). In camels, udder abnormality and mastitis were significantly higher in late lactation than in early lactation. Mastitis tends to increase with parity in camels. E. coli isolates were highly resistant to spectinomycin, vancomycin, and doxycycline, whereas most S. aureus isolates were multidrug-resistant. Most of the rural and periurban communities in this area consume raw milk, which indicates a high risk of infection with multidrug-resistant bacteria. We recommend community-focused training programs to improve community awareness of the risk of raw milk consumption and the need to boil milk.

Abstract

A study was carried out from August 2017 to February 2018 on lactating dairy cows, one-humped dromedary camels, and goats to determine mastitis in the Bule Hora and Dugda Dawa districts of in Southern Ethiopia. Milk samples from 564 udder quarters and udder halves from 171 animals consisting of 60 dairy cows, 51 camels, and 60 goats were tested for mastitis. Sixty-four positive udder milk samples were cultured, and bacterial mastitis pathogens were isolated and identified. The antibiotic resistance of bacterial isolates from milk with mastitis was tested against nine antimicrobials commonly used in the study area. Cow- and quarter-level prevalence of mastitis in dairy cows, camels, and goats was 33.3%, 26.3%, and 25% and 17.6%, 14.5%, and 20%, respectively. In cattle, the prevalence was significantly higher in Dugda Dawa than in Bule Hora. Major bacterial isolates were coagulase-negative Staphylococcus species (39.1%), S. aureus (17.2%), S. hyicus (14.1%), and S. intermedius and Escherichia coli (9.4% each). In camels, udder abnormality and mastitis were significantly higher in late lactation than in early lactation. Mastitis tends to increase with parity in camels. E. coli isolates were highly resistant to spectinomycin, vancomycin, and doxycycline, whereas most S. aureus isolates were multidrug-resistant. Most of the rural and periurban communities in this area consume raw milk, which indicates a high risk of infection with multidrug-resistant bacteria. We recommend a community-focused training program to improve community awareness of the need to boil milk and the risk of raw milk consumption.

Energy, nitrogen partitioning, and methane emissions in dairy goats differ when an isoenergetic and isoproteic diet contained orange leaves and rice straw crop residues

The aim of this study was to evaluate the effects of incorporating rice straw and orange leaves into the diets for goats. Ten Murciano-Granadina goats at mid lactation weighing 45 ± 0.3 kg were used in a crossover design. Two isoproteic and isoenergetic diets (180 g/kg DM and 17 MJ/kg DM, respectively) with alfalfa hay as forage source (33% of DM) were fed. A control diet (CON) incorporated barley as energy source and soy hulls as fiber component. The experimental diet (ORG) replaced barley and soy hulls with orange leaves (19% on DM basis), rice straw (12%, on DM basis) and soya oil (2%). Peas and horsebeans were the protein source in both diets. Each goat received the 2 treatments in 2 periods. Goats were fed the experimental diets and after 14 d on their respective treatments moved to individual metabolism cages for another 7 d. Subsequently, feed intake, total fecal and urine output and milk yield were recorded daily over the first 5 d. During the next 2 d ruminal fluid and blood samples were collected, and then individual gas-exchange measurements were recorded by a mobile open-circuit indirect calorimetry system using a head box. No differences in dry matter intake were detected, and apparent total-tract digestibility was greater in CON than ORG. Efficiency of metabolizable energy intake for milk and maintenance also was lower in response to ORG (0.65 vs. 0.63), with energy balance being negative (-12 kJ/kg of BW^0.75) due to mobilization of fat (-16 g/animal vs. 68 g/animal for ORG and CON, respectively). Although actual milk yield was lower in goats fed ORG (2.32 vs. 2.06 kg/d, respectively), energy-corrected milk did not differ (2.81 kg/d on average). In terms of milk quality, milk fat content, and concentrations of monounsaturated (18.54 vs. 11.55 g/100 g milk fat) and polyunsaturated fatty acids (5.75 vs. 3.99 g/100 g milk fat) were greater in goats fed ORG. Based on various indices, the milk produced by ORG would be less atherogenic and thrombogenic than CON milk. Compared with CON, enteric CH₄ emission was lower due to feeding ORG (reduction of 38 g CH₄/kg milk fat). Data suggest that greater fat mobilization in goats fed ORG might have been due to the apparent lack of synchrony between degradable protein and carbohydrate and the lipogenic nutrients associated with the lower cereal content of the ORG diet. Thus, goats fed ORG seemed to rely more on fat depots to help meet energy requirements and reach optimal performance. As such, the lower content of glucogenic nutrients in ORG did not favor body fat deposition and partitioning of ME into body tissue. Overall, responses in terms of CH₄ emissions and milk quality suggest that inclusion of rice straw and orange leaves in diets for small ruminants could be a valuable alternative to reuse, recycle and revalue agricultural by-products.

Potassium carbonate as a supplement to improve milk fat concentration and yield in early-lactating dairy goats fed a high-starch, low-fiber diet

This study investigated the use of K₂CO₃ as dietary buffer to prevent or to recover from low milk fat production when early-lactating dairy goats are fed a high-starch, low-fiber (HSLF) diet. At kidding, 30 Alpine goats housed in pens with Calan gate feeders received a total mixed ration with a forage-to-concentrate ratio of 55:45 on a dry matter (DM) basis for a baseline period of 27 ± 4 d. Goats (milk yield, 4.14 ± 0.88 kg/d; milk fat, 4.28 ± 0.52%; mean ± SD) were then assigned to 1 of 10 blocks according to parity (first vs. second or more) and milk fat concentration, and fed a HSLF diet containing 45% forages and 55% concentrates for 2 experimental periods of 28 d. Treatments were identified as (1) control, in which the HSLF diet was fed throughout both periods; (2) preventive, in which the HSLF diet supplemented with K₂CO₃ (1.6% of DM) was fed during both periods; and (3) recovery, in which the HSLF diet was fed during the first period (P1) and the HSLF diet supplemented with K₂CO₃ was fed during the second period (P2). Data from P1 and P2 were analyzed separately. In P1, preplanned contrasts were used to evaluate the preventive effect of K₂CO₃ (control and recovery, both groups receiving the same diet during this period, vs. preventive), and in P2, to assess the potential of K₂CO₃ to alleviate an already existing state of low milk fat (control vs. recovery and preventive vs. recovery). Feeding the HSLF diet in P1 moderately decreased milk fat concentration (-16%) and yield (-13%) as compared with baseline. Dietary addition of K₂CO₃ decreased DM intake by 12 and 14% in P1 and P2, respectively. Ruminal pH was not different among treatments. There was also no significant difference in milk yield (4.13 and 3.71 kg/d on average in P1 and P2, respectively) for any tested contrasts. In P1, milk fat concentration and yield did not differ among goats fed control (3.58% and 151 g/d, respectively) and preventive (3.67% and 148 g/d, respectively) diets. In P2, milk fat concentration and yield did not differ among goats fed the control diet (3.38% and 137 g/d, respectively), and diets where K₂CO₃ was used as preventive (3.44% and 126 g/d, respectively) or recovery treatment (3.25% and 113 g/d, respectively). Supplementing a high-concentrate diet with 1.6% K₂CO₃ was therefore not effective in either preventing or suppressing already existing conditions of low milk fat production in dairy goats.

Use of Principal Component Analysis to Combine Genetic Merit for Heat Stress and for Fat and Protein Yield in Spanish Autochthonous Dairy Goat Breeds

Simple Summary

Tolerance to heat stress (HS) is an important economic trait in goats to maintain dairy farm profitability. We studied the effect of a climatological index of temperature and relative humidity (THI) on test day record (TD) of fat and protein yield (fpy) in the three main Spanish dairy goat breeds (Florida, 126.825 TD, Malagueña, 141.856 TD and Murciano Granadina, 62.834 TD), analysing the nature of the fpy response throughout the THI on the weeks of lactation (DIM) trajectories. The results showed the existence of a double genotype environment interaction between DIM and THI and a depression in the fpy level in animals kept in the hot zone (THI > 25) compared with those in the cold zone (THI ≤ 16). This negative impact is equivalent to 13 to 30 days in production. We propose an alternative to select animals by using a principal analysis of the estimated breeding value for each goat breed across DIM and THI scales. The results of this study show that this procedure is a powerful tool to select the most productive and heat-tolerant animals, thus contributing to the increased profitability of autochthonous Spanish goat breeds.

Abstract

We studied the effect of the Temperature Humidity Index (THI) (i.e., the average of temperature and relative humidity registered at meteorological stations) closest to the farms taken during the test day (TD), for total daily protein and fat yields (fpy) of the three main Spanish dairy goats. The data were from Florida (11,244 animals and 126,825 TD), Malagueña (12,215 animals and 141,856 TD) and Murciano Granadina (5162 animals and 62,834 TD) breeding programs and were studied by different linear models to estimate the nature of the fpy response throughout the THI and the weeks of lactation (Days in Milk, DIM) trajectories. The results showed an antagonism between THI and DIM, with a marked depression in the fpy level in animals kept in the hot zone of the THI values (THI > 25) compared with those in the cold zone (THI ≤ 16), with a negative impact equivalent to production of 13 to 30 days. We used a Reaction Norm model (RN), including THI and DIM as fixed covariates and a Test Day Model (TDM), to estimate the genetic (co)variance components. The heritability and genetic correlations estimated with RN and TDM showed a decreased pattern along the scale of THI and DIM, with slight differences between breeds, meaning that there was significant genetic variability in the animal’s ability to react to different levels of THI, which is not constant throughout the DIM, showing the existence of genotype-environment interaction. The breeding values (BV) of all animals for each level of THI and DIM were subject to a principal component analysis, and the results showed that 89 to 98% of the variance between the BV was explained by the two first eigenvalues. The standardized BV were weighted with the corresponding eigenvector coefficients to construct an index that showed, in a single indicator, the most complete expression of the existing genetic variability in the animals’ ability to produce fpy along the trajectories of THI and DIM. This new option will make it easier to select animals which are more productive, and with better adaptability to heat stress, as well as enabling us to exploit genetic variations in the form of the response to heat stress to be adapted to different production systems.

Selection Criteria for Improving Fertility in Spanish Goat Breeds: Estimation of Genetic Parameters and Designing Selection Indices for Optimal Genetic Responses

The aim of this study was to estimate genetic parameters for several female fertility criteria and to choose the most suitable selection index in Spanish Florida and Payoya goat breeds. In this study, we analyzed as fertility traits, the age at first kidding (AgFiKid), and the interval between the first and second kiddings (Int12Kid), between the second, third, and remaining kiddings (Int3toKid), and between all kiddings (IntAllKid) in 51,123 and 22,049 Florida and Payoya females, respectively. Genetic parameters were estimated by fitting animal models using restricted maximum likelihood (REML) methodology. We proposed six selection indices to compare the genetic responses for all traits included, based on a new selection index theory. The heritability and repeatability estimates of the traits were low, as expected. The genetic correlations among fertility traits covered a wide range of values from 0.07 (AgFiKid-Int12Kid) to 0.71 (Int3toKid-IntAllKid) in Florida and from -0.02 (AgFiKid-Int12Kid) to 0.82 (Int3toKid-IntAllKid) in Payoya. Overall, the results of this study indicate that IntAllKid gives the highest genetic responses in both breeds but is expressed late in a female's life. However, AgFiKid and Int12Kid could be recommended as early selection criteria for female fertility in both breeds.

Effects of subacute ruminal acidosis on colon epithelial morphological structure, permeability, and expression of key tight junction proteins in dairy goats

The hindgut epithelial barrier plays an important role in maintaining absorption and immune homeostasis in ruminants. However, little information is available on changes in colon epithelial barrier structure and function following grain-induced subacute ruminal acidosis (SARA). The objective of this study was to investigate the effects of grain-induced SARA on colon epithelial morphological structure, permeability, and gene expression involved in epithelial barrier function. Twelve mid-lactating (136 ± 2 d in milk; milk yield = 1.68 ± 0.15 kg/d) Saanen dairy goats with 62.13 ± 4.76 kg of body weight were randomly divided into either the control (CON) treatment (n = 6) or SARA treatment (n = 6). The CON goats were fed a basal diet with a nonfiber carbohydrates to neutral detergent fiber ratio of 1.15 for 60 d. The SARA goats were fed 4 diets with increasing nonfiber carbohydrates to neutral detergent fiber ratio at 1.15, 1.49, 2.12, and 2.66 to induce SARA, with each diet (referred to as period) being fed for 15 d, including 12 d for adaptation and 3 d for sampling. Continuous ruminal pH recordings were used to diagnose the severity of SARA. Additionally, colonic tissues were collected to evaluate the epithelial morphological structure, permeability, and expression of tight junction proteins using transmission electron microscopy, Ussing chamber, quantitative real-time PCR, and Western blotting. Profound disruption in the colonic epithelium was mainly manifested as the electron density of tight junctions decreased, intercellular space widened, and mitochondria swelled in SARA goats. Colon epithelial short-circuit current, tissue conductance, and the mucosal-to-serosal flux of fluorescein isothiocyanate-dextran 4 kDa were increased and potential difference was decreased in SARA goats compared with CON goats. Subacute ruminal acidosis increased mRNA and protein expression levels of CLDN1 and OCLN in the colonic epithelium. Overall, the data of the present study demonstrate that SARA can impair the barrier function of the colonic epithelium at both structural and functional levels, which is associated with severe epithelial structural damage and increased permeability and changes in the expression of tight junction proteins.

Conditioning Factors of Linearized Wood's Function Lactation Curve Shape Parameters, Milk Yield, Fat and Protein Content in Murciano-Granadina Primiparous Does

Simple Summary

Strategies aiming to improve milk yield and quality are essential to maximizing profitability and dairy goat chain efficiency, which in turn optimizes the commercialization of the products derived. A total of 137,927 official controls were traced and recorded from 22,932 Murciano-Granadina primiparous goats between 1996 and 2016. In this regard, the effects of conditioning factors related to kidding (such as type, year and season) and farm were evaluated to detect the phenotypic sources of variation of milk yield, fat content, protein content and curve shape parameters in Murciano-Granadina primiparous goats to provide useful information for dairy goat early selection.

Abstract

A total of 137,927 controls of 22,932 Murciano-Granadina first lactation goats (measured between 1996–2016) were evaluated to determine the influence of the number of kids, season, year and farm on total milk yield, daily milk yield, lactation length, total production of fat and protein and percentages of fat and protein. All factors analyzed had a significant effect on the variables studied, except for the influence of the number of kids on the percentages of fat and protein, where the variation was very small. Goats with two offspring produced nearly 15% more milk, fat and protein per lactation compared to goats with simple kids. Kiddings occurring in summer–autumn resulted in average milk, fat and protein yields nearly 14, 19 and 23% higher when compared to winter–spring kiddings. Lactation curves were evaluated to determine the effects of the number of kids and season, using the linearized version of the model of Wood in random regression analyses. Peak Yield increased by about 0.3 kg per additional offspring at kidding, but persistence was higher in goats with single offspring. The kidding season significantly influenced the lactation curve shape. Hence summer-kidding goats were more productive, and peak occurred earlier, while a higher persistence was observed in goats kidding during autumn.

Assessing effects of tannin-rich sainfoin supplements for grazing dairy goats on feed protein efficiency

This research communication presents a study evaluating the effects of dried sainfoin (Onobrychis viciifolia) supplemented to dairy goats on their milking performance and feed protein efficiency under commercial conditions. During July and August 2015, a herd of 20 Alpine goats was divided into two treatments (n = 10), balanced by milk yield and days in milk. They were supplied with either 700 g/d sainfoin pellets (condensed tannins: 4.0 g/kg DM) or 700 g/d lucerne (Medicago sativa) pellets (condensed tannins: 0.3 g/kg DM). The goats remained in one herd and were separated by treatments only during milking. In the milking parlour each goat received 350 g of the respective pellets, twice daily. During the day, the herd had 5 h access to a high-quality pasture (crude protein >200 g/kg DM), whilst during the rest of the day and the night animals were housed and offered grass hay ad libitum. The experiment lasted for seven weeks. Individual milk yields and composition were controlled in weeks 1, 3, 5, and 7 after the start of the experiment. No differences between the treatments were found, either for milk, protein or urea yields, nor for protein, urea and fat concentrations. Urea to protein ratio in milk was lower with the sainfoin treatment. In conclusion, sainfoin compared to lucerne, supplied for 7 weeks to dairy goats at approximately 25% of the diet, had only weak beneficial and no adverse effects on milking performance, milk composition and feed protein efficiency under commercial conditions of pasture-based dairy production.

Comprehensive Transcriptome Profiling of Dairy Goat Mammary Gland Identifies Genes and Networks Crucial for Lactation and Fatty Acid Metabolism

Milk fatty acids secreted by the mammary gland are one of the most important determinants of the nutritional value of goat milk. Unlike cow milk, limited data are available on the transcriptome-wide changes across stages of lactation in dairy goats. In this study, goat mammary gland tissue collected at peak lactation, cessation of milking, and involution were analyzed with digital gene expression (DGE) sequencing to generate longitudinal transcript profiles. A total of 51,299 unigenes were identified and further annotated to 12,763 genes, of which 9,131 were differentially expressed across various stages of lactation. Most abundant genes and differentially expressed genes (DEGs) were functionally classified through clusters of euKaryotic Orthologous Groups (KOG), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. A total of 16 possible expression patterns were uncovered, and 13 genes were deemed novel candidates for regulation of lactation in the goat: POLG, SPTA1, KLC, GIT2, COPS3, PDP, CD31, USP16/29/37, TLL1, NCAPH, ABI2, DNAJC4, and MAPK8IP3. In addition, PLA2, CPT1, PLD, GGA, SRPRB, and AP4S1 are proposed as novel and promising candidates regulating mammary fatty acid metabolism. “Butirosin and neomycin biosynthesis” and “Glyoxylate and dicarboxylate metabolism” were the most impacted pathways, and revealed novel metabolic alterations in lipid metabolism as lactation progressed. Overall, the present study provides new insights into the synthesis and metabolism of fatty acids and lipid species in the mammary gland along with more detailed information on molecular regulation of lactogenesis. The major findings will benefit efforts to further improve milk quality in dairy goats.

Comparison of Standard Electrocardiography and Smartphone-Based Electrocardiography Recorded at Two Different Anatomic Locations in Healthy Meat and Dairy Breed Does

Smartphones present multiple applications for ambulatory practice. One of the newer technologies is smartphone-based electrocardiography (ECG). While this technology has been explored in horses and cattle, it has not yet been evaluated for goats. Fifteen goats of dairy and meat breeds were simultaneously tested with both a standard and smartphone-based ECG from two different anatomic locations (base apex and sternal positions). ECGs were compared for quality score, heart rate, and ECG intervals. Smartphone-based ECGs were feasible to collect in all goats under field settings. Scoring indicated higher quality scores for the standard ECG when compared to the smartphone-based ECG, and differences in smartphone ECG quality scores were noted between goats of different body types. Heart rate agreement was noted between measurements taken from smartphone-based and standard devices. ECG intervals calculated for smartphone-based ECGs were clinically similar to standard ECG. While not of the same diagnostic quality as standard ECG recordings, smartphone-based ECGs for goats present an easy to collect recording for caprine practice.

Validation of Brix refractometers and a hydrometer for measuring the quality of caprine colostrum

On-farm assessment of caprine colostrum quality is important for goat farmers; the ability to quickly recognize whether colostrum is suitable to feed to kids helps achieve successful passive transfer of immunity. The study compared the use of optical and digital Brix refractometers and a hydrometer against the international gold standard radial immunodiffusion (RID), using both fresh and frozen samples. A locally available ELISA methodology was included for comparison. A total of 300 samples were collected from 2 farms (farm 1: n = 157, collected by research staff within 24 h of parturition; farm 2: n = 143, collected by the farmer within 12 h of parturition). Farm 1 provided doe age for a subset of samples (n = 86). Samples were tested fresh and then frozen for shipment and repeated testing. Specific gravity was measured using a hydrometer in a subset of samples (n = 22) from farm 2. Because no gold standard thresholds are currently available for caprine colostrum, RID-derived values of 30, 40, and 50 g/L IgG were used as potential "good quality" thresholds. Pearson (ρ) and Lin's concordance correlation coefficients (CCC) were calculated for comparison of methods. Optimum thresholds were established maximizing the Youden index and minimizing the "distance closest to the top left corner" of the receiver operator characteristic curves. Brix values were correlated with RID (optical Brix, fresh: ρ = 0.73; digital Brix, fresh: ρ = 0.71; digital Brix, frozen: ρ = 0.76) and with each other (range: ρ = 0.93 to 0.99; CCC = 0.91 to 0.99). Specific gravity measured by the hydrometer yielded a strong relationship with RID (ρ = 0.83) and with Brix values (range: ρ = 0.88 to 0.90). The ELISA method was not correlated with Brix methods (range: ρ = 0.02 to 0.09) or RID (ρ = 0.20). Depending on the colostrum IgG threshold, the hydrometer yielded high Youden indices (range: 0.78 to 0.93) and low distance closest to the top left corner criteria (0 to 0.05) at a threshold of 1.047 specific gravity. For all RID IgG thresholds, the best Brix threshold (regardless of type or whether the sample was fresh or frozen) was 18 or 19%, with the highest Youden indices (range: 0.47 to 0.61) and lowest distance to the top left corner criteria (range: 0.09 to 0.16); however, we recommend 19%, because this reduces the potential of feeding poor-quality colostrum. The ELISA method was the poorest predictor of colostrum concentration. Age was not found to affect colostrum quality; however, the sample size of this subset was small. Hydrometers are inexpensive and easy to use, whereas Brix methods use only a small amount of colostrum; we suggest that either method could be used on-farm.