Factors affecting birth weight in sheep: maternal environment

Prenatal AAV9-GFP administration in fetal lambs results in transduction of female germ cells and maternal exposure to virus

Prenatal somatic cell gene therapy (PSCGT) could potentially treat severe, early-onset genetic disorders such as spinal muscular atrophy (SMA) or muscular dystrophy. Given the approval of adeno-associated virus serotype 9 (AAV9) vectors in infants with SMA by the U.S. Food and Drug Administration, we tested the safety and biodistribution of AAV9-GFP (clinical-grade and dose) in fetal lambs to understand safety and efficacy after umbilical vein or intracranial injection on embryonic day 75 (E75) . Umbilical vein injection led to widespread biodistribution of vector genomes in all examined lamb tissues and in maternal uteruses at harvest (E96 or E140; term = E150). There was robust GFP expression in brain, spinal cord, dorsal root ganglia (DRGs), without DRG toxicity and excellent transduction of diaphragm and quadriceps muscles. However, we found evidence of systemic toxicity (fetal growth restriction) and maternal exposure to the viral vector (transient elevation of total bilirubin and a trend toward elevation in anti-AAV9 antibodies). There were no antibodies against GFP in ewes or lambs. Analysis of fetal gonads demonstrated GFP expression in female (but not male) germ cells, with low levels of integration-specific reads, without integration in select proto-oncogenes. These results suggest potential therapeutic benefit of AAV9 PSCGT for neuromuscular disorders, but warrant caution for exposure of female germ cells.

Foetal programming in sheep: Reproductive and productive implications

The aim of this study was to evaluate the effects of pregnant ewe nutrition on the performance of offspring in terms of meat, wool production, and reproduction. Foetal programming in sheep has focused on several aspects related to foetal growth, postnatal production, behaviour, and immunological performance. Currently, significant efforts are being made to understand the endocrine, metabolic, and epigenetic mechanisms involved in offspring development. Current studies have not only evaluated the foetal period, despite the pre-conception parental nutrition has demonstrated an effect on the foetal, embryonic, and pre-implantation periods and can generate permanent effects in the foetal and postnatal phases. The performance of offspring is the result of interactions between the genome, epigenome, and environmental interventions during conception. Several factors influence the expression of phenotypic characteristics in progenies; however, this study focused on presenting data on the effect of pregnant ewe nutrition alone on foetal growth and the productive aspects of their offspring.

Placental Nanoparticle-mediated IGF1 Gene Therapy Corrects Fetal Growth Restriction in a Guinea Pig Model

Fetal growth restriction (FGR) caused by placental insufficiency is a major contributor to neonatal morbidity and mortality. There is currently no in utero treatment for placental insufficiency or FGR. The placenta serves as the vital communication, supply, exchange, and defense organ for the developing fetus and offers an excellent opportunity for therapeutic interventions. Here we show efficacy of repeated treatments of trophoblast-specific human insulin-like 1 growth factor ( IGF1 ) gene therapy delivered in a non-viral, polymer nanoparticle to the placenta for the treatment of FGR. Using the guinea pig maternal nutrient restriction model of FGR, nanoparticle-mediated IGF1 treatment was delivered to the placenta via ultrasound guidance across the second half of pregnancy, after establishment of FGR. This treatment resulted in correction of fetal weight in MNR animals compared to control, improved fetal physiology and no negative maternal side-effects. Overall, we show for the first time a therapy capable of improving the entire pregnancy environment: maternal, placental, and fetal. This combined with our previous studies using this therapy at both mid pregnancy and in numerous cell and animal models demonstrate the plausibility of this therapy for future human translation to improve health outcomes of neonates and decrease numerous morbidities associated with the developmental origins of disease.

Physiological response to fetal intravenous lipid emulsion

In preterm neonates unable to obtain sufficient oral nutrition, intravenous lipid emulsion is life-saving. The contribution of post-conceptional level of maturation to pathology that some neonates experience is difficult to untangle from the global pathophysiology of premature birth. In the present study, we determined fetal physiological responses to intravenous lipid emulsion. Fetal sheep were given intravenous Intralipid 20® (n = 4 females, 7 males) or Lactated Ringer's Solution (n = 7 females, 4 males) between 125 ± 1 and 133 ± 1 d of gestation (term = 147 d). Manufacturer's recommendation for premature human infants was followed: 0.5-1 g/kg/d initial rate, increased by 0.5-1 to 3 g/kg/d. Hemodynamic parameters and arterial blood chemistry were measured, and organs were studied postmortem. Red blood cell lipidomics were analyzed by LC-MS. Intravenous Intralipid did not alter hemodynamic or most blood parameters. Compared with controls, Intralipid infusion increased final day plasma protein (P=0.004; 3.5 ± 0.3 vs. 3.9 ± 0.2 g/dL), albumin (P = 0.031; 2.2 ± 0.1 vs. 2.4 ± 0.2 g/dL), and bilirubin (P<0.001; conjugated: 0.2 ± 0.1 vs. 0.6 ± 0.2 mg/dL; unconjugated: 0.2 ± 0.1 vs. 1.1 ± 0.4 mg/dL). Circulating IGF-1 decreased following Intralipid infusion (P<0.001; 66 ± 24 vs. 46 ± 24 ng/mL). Compared with control Oil Red O liver stains (median score 0), Intralipid-infused fetuses scored 108 (P=0.0009). Lipidomic analysis revealed uptake and processing of infused lipids into red blood cells, increasing abundance of saturated fatty acids. The near-term fetal sheep tolerates intravenous lipid emulsion well, although lipid accumulates in the liver. Increased levels of unconjugated bilirubin may reflect increased red blood cell turnover or impaired placental clearance. Whether Intralipid is less well tolerated earlier in gestation remains to be determined.

Genome-wide association study of early liveweight traits in fat-tailed Akkaraman lambs

Small ruminants, especially sheep, are essential for sustainable agricultural production systems, future food/nutrition security, and poverty reduction in developing countries. Within developed countries, the ability of sheep to survive on low-quality forage intake could act as buffer against climate change. Besides sheep's importance in sustainable agricultural production, there has been less ongoing work in terms of sheep genetics in Near East, Middle East and in Africa. For lamb meat production, body weight and average daily gain (ADG) until weaning are critical economic traits that affects the profitability of the industry. The current study aims to identify single nucleotide polymorphisms (SNPs) that are significantly associated with pre-weaning growth traits in fat tail Akkaraman lambs using a genome-wide association study (GWAS). A total of 196 Akkaraman lambs were selected for analysis. After quality control, a total of 31,936 SNPs and 146 lambs were used for subsequent analyses. PLINK 1.9 beta software was used for the analyses. Based on Bonferroni-adjusted p-values, one SNP (rs427117280) on chromosome 2 (OAR2) had significant associations with weaning weight at day 90 and ADG from day 0 to day 90, which jointly explains a 0.8% and 0.9% of total genetic variation respectively. The Ovis aries natriuretic peptide C (NPPC) could be considered as a candidate gene for the defined significant associations. The results of the current study will help to increase understanding of the variation in weaning weight and ADG until weaning of Akkaraman lambs and help enhance selection for lambs with improved weaning weight and ADG. However, further investigations are required for the identification of causal variants within the identified genomic regions.

Uterine dynamics, blood profiles, and electronic fetal monitoring of primiparous and multiparous bitches classified according to their weight

Perinatal mortality occurs in all species. In dogs, mortality rates have been reported to range from 5 to 35%. Electronic fetal and uterine monitoring has recently been used in domestic animals to monitor the mother and newborn before and during parturition. In this way, the fetal heart rate and uterine dynamics can be monitored. This study evaluated the uterine dynamics of bitches with different weights and parity. Ninety-six bitches and their 476 puppies were divided into four experimental groups containing 24 individuals each (12 primiparous bitches and 12 multiparous bitches), according to body weight: G1 (4-8 kg), G2 (8.1-16 kg), G3 (16.1 to 32 kg), and G4 (32.1 to 39.6 kg). The fetal heart rate decelerations (dip 2 patterns), uterine dynamics, and bitches' blood profiles were evaluated, including levels of glucose, lactate, pCO2, pO2, pH, HCO3-, and Ca++. The dam weight can affect the vitality of newborns and the uterine dynamics, with differences in the frequency, intensity, and duration of myometrial contractions. The expulsion interval between puppies was longest in primiparous bitches with low weight and shortest in multiparous bitches with high weight. The expulsion interval and the number of stillborn females were higher in primiparous bitches with high weight. Newborn male puppies were significantly heavier than newborn females.

Parity and housing effects on the behavioural and hypothalamic-pituitary-adrenal axis responses of pregnant ewes

It is common in many countries for sheep to be housed during winter from mid-gestation until lambing to protect ewes and lambs from adverse conditions and improve late gestation nutritional management. Keeping ewes indoors, however, has its own challenges as the animals may be mixed with unfamiliar conspecifics, have limited floor and feeding space, experience changes to their diet and increased handling by humans. Therefore, the objective of this study was to investigate the effect of variation in housing management (space allowance and social stability) on the behaviour and hypothalamic-pituitary-adrenal (HPA) axis responses of pregnant ewes from mid-to-late gestation (weeks 11-18 of pregnancy). Seventy-seven ewes (41 primiparous, 36 multiparous) were divided into two groups: 'Control' and 'Restricted space and mixed' (RS-Mix), where RS-Mix ewes were allocated half the amount of space (1.27 vs 2.5 m2 for RS-Mix and Control, respectively) and feedface (concentrate feeder space) allowance (36 vs 71 cm per ewe) given to the Control group and were also subjected to two social mixing events. Aggressive behaviour at the feedface and time spent standing, lying, walking, feeding and ruminating were recorded and faecal samples were collected for assessment of faecal glucocorticoid metabolite (FGM) concentrations. Higher aggression was observed in RS-Mix ewes during the first week of observation (P = 0.044), which gradually declined to the same level as Control ewes by the end of the study (P = 0.045). RS-Mix ewes were significantly less likely to be able to freely join the feedface compared to Controls (P = 0.022). No other significant treatment effects on aggressive behaviour or FGM during gestation were found. RS-Mix ewes displayed significantly higher ruminating behaviour at week 18 of gestation compared to Control ewes (P < 0.001), but no other effects were seen on general pen behaviour. However, the effect of indoor housing had a significant impact on primiparous ewes, who had lower weight gain (P = 0.015) and higher FGM concentrations (P = 0.014) compared to multiparous ewes regardless of treatment group. The data suggest that, although no sustained effects on behaviour or HPA axis responses were seen with the differences in space and feeder allowance or social stability at the levels used in this study, inexperienced (primiparous) ewes may find indoor housing more stressful; and are less able to adapt compared to multiparous ewes. These effects may influence the behaviour of the ewe at lambing time, and her offspring.

Colostrum traits and newborn body weight and growth: comparison between single and twin underfed sheep pregnancies

Maternal nutrition during gestation plays an important role in colostrum production, postnatal growth, and survival of newborn lambs, especially in twin gestations. This research aimed to investigate the effects of chronic natural undernutrition on colostrum traits and early lamb's postnatal growth born from single and twin sheep pregnancies developed in a restrictive prairie, representative of southern Patagonia. Single- and twin-bearing ewes (n = 20 per group) were maintained grazing in a natural pasture. At 140 days of gestation, ewes were placed in individual pens for lambing control. Colostrum was collected immediately after delivery and at 12, 24, and 36 h postpartum, for determination of yield and composition. Maternal blood was obtained at 140 days of gestation and at lambing for plasma glucose, progesterone, 17β-estradiol, and IgG determination. Newborn lamb blood for determining glycaemia and IgG was collected at birth and at 12, 24, 36, and 120 h after birth. Lamb mortality and growth was assessed from birth until 30 days of life. No differences were observed in progesterone and 17β-estradiol. There were no differences in colostrum yields and fat components, however single- had higher values of protein and lactose than twin-bearing ewes (p < 0.05 for both). Singletons had higher glycaemia than twins at 12 h postpartum (102.2 ± 32.8 vs. 73.4 ± 29.9 mg/dL, p < 0.05). Colostrum IgG content was similar at delivery but higher in single ewes at 12 and 24 h, reaching a similar values at 36 h (4.7 ± 9.7 and 5.8 ± 7.7 mg/mL in single and twin pregnancies, respectively). Newborn IgG was higher in singletons compared to twins at least until 48 h of life. Lams body weight was always superior in singleton than twins from birth until 30 days of life. Mortality did not differ during the first week of life, but it increased significantly only in twins until day 30 of life. Undernourishment in pregnant ewes affected colostrum quantity and quality, resulting in a lower postnatal growth and a higher mortality in twins. Alternative managements favoring fetal growth, birth weight and neonatal viability in twin sheep pregnancies are needed, when flocks are breed under harsh environments.

Maternal Age, Parity and Nursing Status at Fertilization Affects Postpartum Lactation Up to Weaning in Horses

Nulliparity is associated with intra-uterine growth retardation and foal delayed catch-up growth. Older mares produce larger/taller foals than the precedents. Nursing at conception on foal growth had not been investigated yet. In any case, milk production conditions the foal's growth. This study aimed to determine effects of mare parity, age and nursing on subsequent lactation quantity and quality. Saddlebred mares and their foals (N = 43) run as a single herd over the same year were: young (6-7-year-old) primiparous, young multiparous, old (10-16-year-old) multiparous nursing at insemination time or old multiparous barren the previous year. No young nursing nor old multiparous mares were available. Colostrum was collected. Milk production and foal weight were monitored at 3-, 30-, 60-, 90- and 180-days postfoaling. The foal average daily weight gain (ADG) was calculated for each period between two measurements. Milk fatty acid (FA), sodium, potassium, total protein and lactose contents were determined. The primiparous versus multiparous colostrum was richer in immunoglobulin G, with lower production but greater FA contents in milk. The primiparous foals had a lower ADG for 3 to 30 days postpartum period. Old mares' colostrum contained more SFA and less polyunsaturated FA (PUFA) whereas their milk was richer in proteins and sodium and poorer in short-chain-SFA with a reduced PUFA/SFA ratio at 90 days. Nursing mares' colostrum was richer in MUFA and PUFA and late-lactation milk production was reduced. In conclusion, parity, age and nursing at conception affect mare's colostrum and milk production and foal growth and should be considered for broodmares' management.

Association of the single nucleotide polymorphism in CAPN3 gene with growth performance in Merino and Garut (MEGA) backcross sheep

BACKGROUND

Sheep is one of the commodities of livestock which has been known widely in Indonesia for supporting the national food security. Improvement in genetic quality by selection based on genetic markers for growth is necessary to increase meat production. Quantitative trait loci (QTL) analysis in sheep suggests that Calpain 3 gene (CAPN3) gene might be one of the candidate loci affecting growth traits. CAPN3 is located on chromosome 7 sheep expressed in the skeletal muscles. The aim of this study was to investigate polymorphism CAPN3 intron 11 in Merino × Garut (MEGA) backcross using the PCR-RLFP method and to determine their association with growth traits.

RESULTS

SNP intron 11 CAPN3 | BseSI of Merino × Garut (MEGA) backcross sheep was polymorphic and resulted in two alleles of C and T with a frequency of 0.76 and 0.24, respectively, and CC, CT, and TT genotypes with a frequency of 0.54, 0.43, and 0.02, respectively. These loci were found to be in Hardy-Weinberg equilibrium. The SNP CAPN3 | BseSI significantly affected (P < 0.05) the birth weight in Merino × Garut (MEGA) backcross sheep.

CONCLUSION

This result suggests that the CAPN3 | BseSI can be used as a genetic marker for birth weight trait in sheep.

Supplementary Feeding of Grazing Inner Mongolian Cashmere Goats during Pregnancy-Based on "Nutrient Requirements of Cashmere Goats"

This study aimed to conduct precise supplementation for pregnant cashmere goats under grazing based on the feeding standard. Eight Inner Mongolian pregnant cashmere goats of near-average body weight were selected at early gestation (44.41 ± 4.03 kg) and late gestation (46.54 ± 4.02 kg) to measure their nutrient intake. Then, two pregnant cashmere goat flocks, No. 10 (control group, on-farm supplement) and No. 11 (supplemented group, supplement based on standard), with the same goat herd structure and grassland type, were chosen to conduct the supplemental feeding experiment. The results showed that pregnant cashmere goats lacked daily the intake of dry matter, digestive energy, crude protein and most essential mineral elements under grazing. After supplemental feeding, the supplementation based on the feeding standard increased the cashmere length and cashmere length growth volume and decreased the cashmere fineness, with no statistical significance. The goat cashmere yield, goat weight after shearing, single and twin-birth kid weight and kids' mature secondary hair follicle density were significantly higher in the supplemented group (p < 0.05). In conclusion, supplementation in accordance with "Nutrient Requirements of Cashmere Goats" can enhance pregnant cashmere goats' fiber production, growth performance, fertility and kids' secondary hair follicles development, which is of great importance for the healthy and precise nutrition and management of cashmere goats.

Role of maternal variables on the development of neonatal hypoglycaemia and influence of neonatal hypoglycaemia on performance of goat kids

The study evaluated the influence of maternal variables (age, body weight and body mass index; BMI) during mating on the development of hypoglycaemia and investigated whether hypoglycaemia at birth impairs thermoregulation, metabolism, body weight gain and immunoglobulin concentration in neonatal goat kids. Post-kidding, the kids born with hypoglycaemia (n = 19) and normoglycaemia (n = 19) were immediately identified and postnatal blood samples, body weight and cardinal physiological variables were determined. Results revealed no significant (P < 0.05) difference in pre-mating maternal variables between dams that kidded hypoglycaemic and normoglycaemic kids. Kids born with hypoglycaemia had lower (P <0.05) blood glucose concentration from birth, until Day 2, when values became comparable between the two groups. Afternoon respiratory and pulse rates were markedly (P < 0.05) unstable in kids born with hypoglycaemia and the early postnatal rise (P < 0.05) in morning rectal temperature in both groups was accompanied by a decrease (P < 0.05) on day 20 in kids born with hypoglycaemia. Blood cholesterol and triglyceride concentrations were lower (P < 0.05) in hypoglycaemic kids and the normoglycaemic kids showed marked increase (P < 0.05) in circulating immunoglobulin concentration 24 h after birth, while age had no (P > 0.05) effect in hypoglycaemic kids. A more pronounced decrease (P < 0.05) in weekly weight gain was observed in hypoglycaemic kids. It was concluded that neonatal goat kids born with hypoglycaemia may have compromised thermoregulation, metabolism and body weight gain, and the cause of hypoglycaemia in kids may not be related to pre-mating maternal variables.

Male fetuses negatively affect the vitality of the litter and the dam's metabolic and physiological state in multifetal pregnant ewe

In sheep, ~30% of fetuses do not survive till parturition, and 17.7% of the multifetal pregnancies experience partial litter loss (PLL). In humans, multifetal pregnancies are associated with a higher risk of perinatal mortality. Therefore, the objectives were to examine the association between partial litter loss, fetal sex, dam's metabolic and physiological state, and pregnancy outcome in multifetal pregnant ewes. The study includes two parts. The first was a retrospective study, in which we analyzed data of 675 lambings and examined the PLL incidence according to male ratio (MR) for all litter sizes (range 2-6). Lambings were categorized as having a low male ratio (LMR; <50% males) or a high male ratio (LMR; >50% males). In the second part, we monitored 24 ewes from 80 to 138 days in pregnancy every 10 days, and then daily until lambing, by ultrasound scanning for maternal heart rate (HR), and Doppler ultrasound for litter vitality. Blood samples were taken from dams on the days of scanning. Male ratio strongly affected PLL, where the general survival rate (for all lambings) was reduced from 90% in LMR lambings to 85% in HMR lambings. The odds ratio for PLL in HMR vs. LMR litters was 1.82. Birth body weight and the survival rate of female was higher in LMR than HMR lambings, with no differences for male lambs in both parameters. In the second part, dams' HR during the last trimester was 9.4% higher in LMR than in HMR pregnancies, with no differences in fetuses' HR. The plasma glucose and insulin concentrations were not significantly different between groups, but plasma β-hydroxybutyrate and nonesterified fatty acid concentrations were, respectively, 31% and 20% lower in HMR vs. LMR ewes. In conclusion, male fetuses negatively affect pregnancy outcomes and influence dams' metabolic and physiological state in sheep.

EVALUATION OF PELIBUEY LAMBS BORN TO MOTHERS PHENOTYPICALLY SEGREGATED ACCORDING TO RESISTANCE TO GASTROINTESTINAL NEMATODES IN THE HUMID TROPICS OF MEXICO

The objective was to evaluate the effect of the resistance of ewes to gastrointestinal nematodes (GIN) on the parasitologic and productive performance of their lambs during preweaning and postweaning periods. Offspring from 44 Pelibuey ewes classified as resistant or susceptible to GIN were evaluated. During the preweaning period, birth weight (BW), live weight (LW) at 35 and 70 days of age, and live weight changes (LWC) were determined in 73 lambs. During the postweaning period, 20 lambs to susceptible or resistant ewes were evaluated. The lambs were challenged under natural GIN infections and artificial infection with L3 of Haemonchus contortus. The fecal egg count (FEC), hematocrit (HT), peripheral eosinophil count, plasma protein, LW, and LWC were determined. There were no differences among parameters evaluated during preweaning (P > 0.05). The type of lambing (single or multiple) affected the BW, LW, and LWC (P < 0.01). The sex (male) of the lamb had a positive effect on BW at 35 and 70 days of age (P < 0.05). After weaning, lambs of susceptible ewes showed higher FEC than resistant ewes (P < 0.05). The HT of lambs to resistant ewes was higher than those the susceptible group (P < 0.01). In conclusion, offspring of resistant ewes show low FEC compared with those susceptible during the postweaning stage.

Definition of low birth weight in domestic mammals: a scoping review

In people and animals, low birth weight (LBW) is recognized as highly predictive of health trajectory from the neonatal period to elderly ages. Regarding the neonatal period, although LBW is recognized as a major risk factor for neonatal mortality, there does not appear to be a clear definition of 'when a birth weight should be considered low' in all species. The aim of this work was to use the scientific literature available to map the various thresholds proposed to define LBW in domestic mammals. Using a standardized methodology, a scoping review was conducted through a literature search in three different bibliographic databases. After a two-step screening of 1729 abstracts and full-text publications by two independent reviewers, eleven studies met the inclusion criteria. Selected publications represented six mammalian species (rat, mouse, dog, pig, cow, and rabbit). Birth weight thresholds were identified through six different methods. In addition to the scarcity of scientific literature about the definition of LBW, this scoping review revealed the lack of standardization for the description, evaluation or the pertinence these definitions. Because the health consequences of LBW could be preventable, providing early identification of at-risk neonates, a consensus for the standardized definition of LBW is required.

Growth standard charts for monitoring bodyweight in intact domestic shorthair kittens from the USA

The optimal growth of domesticated cats has not yet been well defined. This study first aimed to create evidence-based growth standards for healthy pet domestic shorthair (DSH) kittens, and then compare the pattern of growth curves depicted by the standards with growth patterns in other healthy DSH kittens and those with abnormal body condition. Data were derived from the clinical records of the BANFIELD® Pet Hospital (BANFIELD) network in the USA and from a research population in the UK (Waltham Petcare Science Institute, UK). A 'modelling' dataset was first created from the BANFIELD records, comprising bodyweight data from immature client-owned DSH cats that had remained healthy and in ideal body condition within the first 2.5y of life. This was used to construct growth centile curves for male and female kittens, covering the age range 8 to 78 weeks, using Generalised Additive Models for Location, Shape and Scale. Growth patterns depicted by the centile curves were compared with the growth patterns of healthy DSH kittens from both research colonies and kittens attending BANFIELD that were classified as overweight or underweight. Overall, there was a broad agreement to the growth standards with approximately half of the research population (206/507, 49%) staying within 2 centile lines of their starting centile, and upward and downward movements outside this range being roughly equally distributed. Compared with the growth standards, the 122 overweight BANFIELD kittens were heavier on average at the start of monitoring and subsequently grew more quickly with 63 (52%) crossing at least 2 standard centile lines upwards. Only 4 underweight DSH kittens were available in the BANFIELD database; compared with the standards, there was a marked initial dip in growth followed by subsequent catch-up growth and 2/4 kittens crossed 2 or more centile lines downwards at some point. Evidence-based growth standards are developed here for male and female sexually-intact DSH kittens. Crossing centiles in an upwards and downwards direction is associated with cats becoming overweight or underweight by early adulthood, respectively. Further work is required to determine whether the clinical use of these growth standards will improve the health and wellbeing of pet cats.

Effect of pre-conceptional nutrition and season on fetal growth during early pregnancy in sheep

Gestational age in sheep can be closely predicted through ultrasonographic measurement of fetal bones when correlated to standardized fetal growth curves. However, these standardized curves do not account for factors that are known modulators of fetal growth, such as maternal nutrition or health status. Despite being seasonal breeders, and studies reporting an effect of season on birth weight, the influence of season on fetal growth has not been well characterized. In this study, we hypothesized that season of conception will affect fetal growth curves during mid-gestation and that pre-conceptional nutrition would have no effect. We investigated this by provisioning treatments of low, control, and high planes of nutrition during the lactation and flushing pre-conceptional periods to multiparous Dorset x Polypay and Dorset ewes over two seasons (the optimal breeding season [n = 97] and the suboptimal breeding season [n = 104]). Females were mated naturally with mating dates recorded, fetal biparietal diameter measured via ultrasound between gestational days 35-71, and newborn weights recorded at lambing. Pre-conceptional nutritional treatments did not affect fetal biparietal diameter. However, low vs. high nutrition in the pre-conceptional lactation (but not flushing) period resulted in reduced lamb birth weights (P < 0.001). Early fetal growth tended to be faster in the suboptimal breeding season than in the optimal breeding season (P < 0.061) with lambs being heavier at birth in the optimal breeding season (P < 0.001). There was no effect of fetal sex or litter size on fetal biparietal diameter during the first half of pregnancy, however both sex and litter size influenced lamb birth weight (P < 0.001) with males being heavier than females and singletons being heavier than twins and triplets. Mating date within the flushing period had a significant effect on lamb birth weight regardless of season and independent of treatment, with ewes that conceived later in the flushing period having heavier lambs at birth (P = 0.007). These findings suggest that pre-conceptional under- or overnutrition resulting in substantial changes in body condition does not affect fetal growth during the first half of pregnancy. However, the reduction in lamb birth weight indicates that pre-conceptional maternal nutrition during the previous lactation period may affect fetal growth later in pregnancy.

Birth weight in the feline species: Description and factors of variation in a large population of purebred kittens

Birth weight is one of the earliest health parameters with short (neonatal period) and long term (adulthood) implications for an individual. The present work was conducted on the domestic cat, with the objective of determining factors affecting kitten birth weight. Data voluntarily shared by 139 French breeders allowed building a large dataset of purebred kittens (n = 3,547) from 15 breeds. A linear mixed model with queen and cattery as random terms was used to investigate variation factors of kitten birth weight such as breed, litter size, season of birth, age of the queen, presence of stillborn in the litter, sex of the kitten. The most important factor was breed which explained 25% of the variation in birth weight observed in the study population. The five other parameters were also significant but explained only a small additional part of the variance (less than 3% each). Analyses showed that kitten birth weight increased with the age of the queen, was higher in males than females and in litters without stillbirth than in litters with at least one stillborn. In addition, lower birth weights were recorded in summer and autumn compared to other seasons, and birth weight values decreased as the number of kittens in the litter increased. In order to group feline breeds according to their average birth weights and litter sizes, a K-means algorithm was used to identify three clusters among the 15 breeds represented (Group 1: small litter sizes/low birth weights; Group 2: large litter sizes/intermediate birth weights; Group 3: large litter sizes/high birth weights). This study, based on a large dataset established at the national scale, provides reference values of feline birth weights for breeders and veterinarians. The next step could be to explore the relationship between birth weight and neonatal mortality to help identify neonates requiring specific care.

Methionine Supplementation during Pregnancy of Goats Improves Kids' Birth Weight, Body Mass Index, and Postnatal Growth Pattern

The last third of gestation is a period of high energy and protein demand for the dam to support fetal growth and the following onset of lactation. Methionine is an essential amino acid that contributes to protein formation, fetal development, and milk synthesis; thus, is likely to have positive effects on the weight and size of the newborn and, afterward, milk yield and milk composition, which may improve growth patterns of the progeny. To test these hypotheses, we used 60 pregnant multiparous Alpine goats with similar live weights and gestational ages (~Day 100 of pregnancy; Mean ± SD; 1410 ± 14 days old and 50.4 ± 6.6 kg) and were separated into two groups: control and supplemented with the delivery. Treatments were T-MET (n = 30; received 1% herbal methionine Optimethione® dry matter based on from Day 100 of the pregnancy to delivery) or T-CTL (n = 30; served as the control and did not receive methionine). The methionine powder provided individual supplementation and was adjusted every week as the live weight and dry matter intake changed. At birth, the weight, body mass index (BMI), birth type, and sex of the kids were determined. Subsequently, the progeny was weighed weekly up to weaning. Two weeks after parturition, the milk composition was recorded weekly, and the milk yield was recorded monthly. The maternal live weight at the start (Mean ± SEM; T-CTL: 50.5 ± 1.1 vs. T-MET: 50.3 ± 1.3 kg) and end (T-CTL: 54.2 ± 1.3 vs. T-MET: 52.8 ± 1.4 kg) of the experiment did not differ statistically among treatments (p > 0.05); however, daily live weight changes tended to differ between groups (T-CTL: 73 ± 10 vs. T-MET: 51 ± 7 g day−1; p = 0.06). The birth weight (T-CTL: 3.1 ± 0.1 vs. T-MET: 3.5 ± 0.1 kg; p < 0.001), daily live weight change (T-CTL: 121 ± 6 vs. T-MET: 141 ± 6 g day−1; p < 0.01), and weaning weight (T-CTL: 8.3 ± 0.2 vs. T-MET: 9.3 ± 0.3 kg; p < 0.01) differed between treatments. The BMI at birth (T-CTL: 0.28 ± 0.01 vs. T-MET: 0.3 ± 0.01 units kg m−2; p < 0.01) and at weaning (T-CTL: 0.85 ± 0.1 kg vs. T-MET: 1.00 ± 0.06 units kg m−2; p < 0.05) differed between treatments. Milk components (protein, fat, lactose, and solids non-fat) and milk yield were similar between treatments (p > 0.05). It is concluded that the inclusion of methionine in the maternal goat diet during the last third of gestation increases the birth and growth variables of the progeny but without significant influence on the milk yield and composition.

Model definition for genetic evaluation of purebred and crossbred lambs including heterosis

Crossbreeding is a common practice among commercial sheep producers to improve animal performance. However, genetic evaluation of U.S. sheep is performed within breed type (terminal sire, semi-prolific, and western range). While incorporating crossbred records may improve assessment of purebreds, it requires accounting for heterotic and breed effects in the evaluation. The objectives of this study were to: 1) describe the development of a paternal composite (PC) line, 2) determine the effect of direct and maternal heterosis on growth traits of crossbred lambs, 3) estimate (co)variance components for direct and maternal additive, and uncorrelated maternal environmental, effects, and 4) provide an interpretation of the estimates of random effects of genetic groups, and to use those solutions to compare the genetic merit of founding breed subpopulations. Data included purebred and crossbred records on birth weight (BN; n = 14,536), pre-weaning weight measured at 39 or 84 d (WN; n = 9,362) depending on year, weaning weight measured at 123 d (WW; n = 9,297), and post-weaning weight measured at 252 d (PW; n = 1,614). Mean (SD) body weights were 5.3 (1.1), 16.8 (3.9) and 28.0 (7.6), 39.1 (7.2), and 54.2 (8.7) kg for BN, WN (at the two ages), WW, and PW, respectively. In designed experiments, the Siremax, Suffolk, Texel, Polypay, Columbia, Rambouillet, and Targhee breeds were compared within the same environment. Estimates of heterotic effects and covariance components were obtained using a multiple trait animal model. Genetic effects based on founders' breeds were significant and included in the model. Percent estimates of direct heterosis were 2.89 ± 0.61, 2.60 ± 0.65, 4.24 ± 0.56, and 6.09 ± 0.86, and estimates of maternal heterosis were 1.92 ± 0.87, 4.64 ± 0.80, 3.95 ± 0.66, and 4.04 ± 0.91, for BN, WN, WW, and PW, respectively. Correspondingly, direct heritability estimates were 0.17 ± 0.02, 0.13 ± 0.02, 0.17 ± 0.02, and 0.46 ± 0.04 for BN, WN, WW, and PW. Additive maternal effects accounted for trivial variation in PW. For BN, WN, and WW, respectively, maternal heritability estimates were 0.16 ± 0.02, 0.10 ± 0.02, and 0.07 ± 0.01. Uncorrelated maternal environmental effects accounted for little variation in any trait. Direct and maternal heterosis had considerable impact on growth traits, emphasizing the value of crossbreeding and the need to account for heterosis, in addition to breed effects, if crossbred lamb information is included in genetic evaluation.

Perinatal complications and maximising lamb survival in an adolescent paradigm characterised by premature delivery and low birthweight

The competition for nutrients in overnourished and still-growing adolescent sheep negatively impacts gestation length, colostrum supply and lamb birthweight, all of which may affect neonatal morbidity and survival to weaning. Herein perinatal complications and the requirement for supplementary feeding were analysed in relation to gestational-intake, and the degree of premature delivery and prenatal growth-restriction exhibited. Pregnancies were established by embryo transfer and the mean/standard deviation (SD) gestation length and birthweight of the optimally-fed control group (n = 100) was used to define early delivery and reduced birthweight categories (1.5 and 3.0 SDs below the control mean for each aspect). Control lambs were largely delivered at term (94%), and had a normal birthweight (92%), while very preterm (≤139days, 18.5%) and preterm delivery (140-142days, 54.8%), extremely low birthweight (ELBW; females ≤2838g and males ≤3216g, 21.1%) and low birthweight (LBW; females 2839 to ≤4001g and males 3217 to ≤4372g, 32.2%), were common in the overnourished group (n = 270, P<0.001). Accordingly, overnourished dams were more likely to lamb without assistance while the incidence of major dystocia was greater in controls. Initial lamb vigour at birth was independent of gestational-intake, delivery or birthweight category but both ELBW and very premature lambs required more assistance with feeding in the first 24h postnatal, primarily reflecting low colostrum availability. Indeed, relative to normal, ELBW lambs had a greater risk of experiencing mismothering, and enhanced likelihood of requiring supplementary feeding throughout the neonatal period (P<0.001). ELBW lambs also had a greater possibility of respiratory issues at birth (P<0.01) and renal complications (P<0.001), while very preterm delivery was associated with an increased risk of gastrointestinal tract problems (P<0.01). In spite of these complications, all-cause mortality was low (5.4%) suggesting that our proactive neonatal care regime can overcome many of the issues associated with extreme prematurity and low birthweight.

Postnatal hypoglycemia and blood glucose concentrations in neonatal tropical goat kids

This study aimed to evaluate the influences of breed, sex, litter size, and birth weight on the incidence of postnatal hypoglycemia and blood glucose concentrations in neonatal tropical goats. A total of 160 neonatal goat kids belonging to Red Sokoto (n = 98), Sahel (n = 40), and West African Dwarf (n = 22) breeds, were categorized after birth based on glycemic status, sex, litter size, and birth weights (high or low). Blood samples were collected on postnatal days 0, 1, 2, 3, 10, and 20 to determine blood glucose concentrations. Results revealed that the incidence of hypoglycemia at birth among neonatal goat kids was 22.5% (36/160) and was significantly (P < 0.05) higher in the Sahel breed kids, twin kids, and kids born with low birth weights. After 24 hours, all hypoglycemic kids became normoglycemic but maintained lower (P < 0.05) blood glucose levels than those that were normoglycemic at birth, until day 10, when both groups had comparable blood glucose levels. In all groups, blood glucose concentrations increased significantly 24 hours postnatal, and kids with high birth weights had significantly higher values than those with low birth weights, while the buck kids had higher values than the doelings. There was a negative correlation (r = -0.31; P < 0.0003) between the blood glucose concentration of dams and those of their kids. In conclusion, the incidence of hypoglycemia in tropical goat kids was markedly influenced by breed, birth weight, and litter size. Furthermore, the hypoglycemic kids maintained lower blood glucose concentrations until day 10 postnatal, suggesting the need for relevant nutritional provisions for hypoglycemic kids during this critical period.

Effect of dietary protein on growth performance, and serum biochemical index in late pregnant Hu ewes and their offspring

The purpose of this study was to investigate the effects of different protein levels in late pregnancy on ewe and lamb growth performance, serum biochemical indexes. Thirty-three ewes (46.4 ± 1.38 kg initial weight) were randomly divided into 3 groups, with 11 ewes in each group. The protein levels of three diets formulated to provide components to meet 10.00 MJ/kg ME requirements diets were: 10.12%, 11.26%, 12.4%. Ewes were raised from the 90th day of pregnancy to the end of delivery, and the lambs were weaned at 60 days. Dietary protein levels had significant effects on blood urea nitrogen, glucose, ammonia nitrogen and triglyceride of ewes (p < 0.05). The height, chest depth, chest circumference, straight crown hip length and curved crown hip length of lambs decreased at first and then increased with the increase of protein. The body length, chest circumference, head width and head length of weaned lambs decreased at first and then increased with the increase of protein. The results showed that when the dietary protein level was increased to 12.4%, the amino acid, glucose and fat metabolism of ewes were affected. The body size development of lambs was better than 10.12% and 11.26% proteins.

Developmental programming of offspring adipose tissue biology and obesity risk

Obesity is reaching epidemic proportions and imposes major negative health crises and an economic burden in both high and low income countries. The multifaceted nature of obesity represents a major health challenge, with obesity affecting a variety of different organs and increases the risk of many other noncommunicable diseases, such as type 2 diabetes, fatty liver disease, dementia, cardiovascular diseases, and even cancer. The defining organ of obesity is the adipose tissue, highlighting the need to more comprehensively understand the development and biology of this tissue to understand the pathogenesis of obesity. Adipose tissue is a miscellaneous and highly plastic endocrine organ. It comes in many different sizes and shades and is distributed throughout many different locations in the body. Though its development begins prenatally, quite uniquely, it has the capacity for unlimited growth throughout adulthood. Adipose tissue is also a highly sexually dimorphic tissue, patterning men and women in different ways, which means the risks associated with obesity are also sexually dimorphic. Recent studies show that environmental factors during prenatal and early stages of postnatal development have the capacity to programme the structure and function of adipose tissue, with implications for the development of obesity. This review summarizes the evidence for a role for early environmental factors, such as maternal malnutrition, hypoxia, and exposure to excess hormones and endocrine disruptors during gestation in the programming of adipose tissue and obesity in the offspring. We will also discuss the complexity of studying adipose tissue biology and the importance of appreciating nuances in adipose tissue, such as sexual dimorphism and divergent responses to metabolic and endocrine stimuli. Given the rising levels of obesity worldwide, understanding how environmental conditions in early life affects adipose tissue phenotype and the subsequent development of obesity is of absolute importance.

Adaptive profiles of Nellore sheep with reference to farming system and season: physiological, hemato-biochemical, hormonal, oxidative-enzymatic and reproductive standpoint

This paper outlines the effect of farming systems with reference to season on the body condition score (BCS) and adaptive profile (physiological, hemato-biochemical, hormonal, enzymatic and reproductive parameters) of Nellore sheep. In trial 1, sixty ewe-lambs were allotted to extensive, semi-intensive, and intensive rearing systems (n = 20) and evaluated for BCS at puberty, mating, 2 weeks pre-lambing and 2, 4, 8, and 12 weeks post-lambing. In trial 2, eighteen rams were distributed evenly to three farming systems (n = 6) and evaluated for physiological, hemato-biochemical, hormonal, enzymatic, and reproductive parameters concerning three seasons. Although the scores did not differ among the groups, the Kruskal-Wallis ranks of BCS revealed a higher energy status of intensive ewes at different physiological conditions. The sheep reared under extensive and semi-intensive systems displayed higher temperature, pulse rate and respiratory rate with predominant effects in summer season. Similarly, both systems exhibited higher WBC and lower haemoglobin, PCV, and RBC contents without affecting MVC, MCH, MCHC, and differential leucocyte count. The percent haemoglobin and RBC count were higher in winter compared to summer months, whereas WBC count followed an exactly opposite pattern. The sheep reared in intensive system showed higher glucose, total protein, albumin, cholesterol, T3, T4, calcium, and phosphorus; however, the globulin, creatinine, uric acid, aspartate amino transferase (AST), alanine amino transferase (ALT), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase, and catalase levels were elevated in extensive and semi-intensive systems. The dartos muscle extension (DME) and scrotum sweating rate (SSR) were higher for the sheep reared under extensive system, especially during summer season; while the seminal parameters viz., total sperm count, progressive sperm motility, and plasma membrane integrity were lower for extensive and semi-intensive sheep. No interactions were noticed for any of the parameters, except for cortisol, DME, and SSR, which showed significant interactions for rearing system vs. season. Our results showed dynamic adaptive mechanisms of the Nellore sheep in relation to different stressors like grazing for long distances, inadequate nutrition, and heat stress, revealing the heat resilient ability in harsh environmental conditions. Further, the analyzed vector plot showed that the AST, GPx, Cortisol, SOD, Catalase, WBC, PR, T4, total abnormalities, and major abnormalities were the major contributors for adapting during combined stressors.

Phenotypic ranking experiments in identifying breeding objective traits of smallholder farmers in northwestern Ethiopia

We executed two live animal ranking experiments, own-flock and group-animal ranking, to identify the breeding objectives of Arab and Oromo goat keepers in northwestern Ethiopia as a preliminary step towards designing sustainable breeding programs for two goat populations. In the own-flock ranking experiment, a total of 147 households, out of which 46 were Arab and 101 were Oromo goat keepers that live in semi-arid and sub-humid agroecologies respectively, were visited at their homesteads and were asked to choose their first best, second best, third best and the most inferior does from their own flock. The reasons of ranking and life history of the does (age, previous production and reproduction information) were inquired and recorded; live body weight and some linear body measurements were taken. In the group-animal ranking experiment, 12 breeding does and 12 breeding bucks from Arab goats and the same number of animals from Oromo goats were randomly selected. Life history of selected does and bucks (age, birth type, libido and temperament) were inquired from the owners. The selected animals were randomly grouped into four in Arab goats (three animals per group) and the same was applied in Oromo goats. Twelve farmers for Arab goats and the same number of farmers for Oromo goats who have not known the experimental animals were invited to do the ranking. Each person ranked the three animals in each group as 1^st, 2^nd and 3^rd, giving reasons of ranking. After a first round of ranking, s/he was then provided with the history of each individual animal and asked whether s/he would consider re-ranking them. This procedure was continued eight times until a person covered all groups of does and bucks. It was found out that in own-flock ranking experiment, keepers focus on productive, reproductive and behavioral traits (such as body size, mothering ability, twinning rate, kidding interval and temperament) while in group-animal ranking experiment, there was a general tendency to focus on observable physical traits like coat color, body size and body conformation. Simultaneous use of both own-flock and group-animal ranking experiments is advisable to identify breeding objective traits in production systems where record keeping is absent.

Energy Supplementation during the Last Third of Gestation Improves Mother-Young Bonding in Goats

Simple Summary

The last third of gestation is a period of high energy demand for the dam, because she needs to support the growth of fetuses and the newborn. Moreover, towards the end of gestation, maternal feed intake is reduced as the mass of the fetoplacental unit increases. The maternal diet often cannot meet nutritional requirements, compromising thermoregulatory capacity, wellbeing, and viability, and the survival of the newborn. We have shown that energy supplementation of the mother during the last third of gestation does not affect progeny birth weight but enhances mother–young bonding.

Abstract

We tested whether maternal energy supplementation during the last third of gestation improves birth weight, neonatal wellbeing, and mother–young bonding. Thirty-six pregnant French Alpine goats were randomly allocated among three nutritional treatments for the last third of pregnancy: (i) Control, fed alfalfa (T-0; n = 12); (ii) alfalfa + 150 g/head daily energy concentrate (T-150; n = 12); (iii) alfalfa + 300 g/head daily energy concentrate (T-300; n = 12). At birth, we collected progeny data on birth weight, birth type, sex, rectal temperature, heart rate, respiratory rate, time to standing, time to udder connection, and time to first feeding. For the dams, we collected data on the duration of labor, time to clean the progeny, and time to allow first suckling. At birth, body weight, rectal temperature, heart rate, and the respiratory rate did not differ among treatments (p > 0.05). In the dams, labor duration was not affected by the treatments (p > 0.05). The T-150 dams were faster to clean the newborn and allow first suckling (p < 0.05). The T-150 progeny were faster to stand and the T-300 progeny were faster to connect to the udder (p < 0.05). We conclude that energy supplementation of the dam during the last third of gestation does not affect the birth weight of the progeny, but enhances the mother–young bonding.

Fetal programming in sheep: effects on pre- and postnatal development in lambs

This systematic review and meta-analysis aim to summarize the effects of maternal undernutrition or overnutrition during pregnancy on fetal weight and morphometric measurements during pregnancy, at birth, and postnatal period in sheep. After completing the search, selection, and data extraction steps, the measure of effect was generated by the individual comparison of each indicator with the average of the control and treated group (undernutrition or overnutrition) using the DerSimonian and Laird method for random effects. Subgroup analyses were also performed for lambing order, litter size, sex, as well as level, timing, and duration of the intervention. Fetal weight during the first third of pregnancy was not affected by maternal undernutrition or overnutrition. On the other hand, undernutrition in the second and last third of gestation reduces the weight of the lamb both during pregnancy, at birth, and during the postnatal period, requiring at least 120 postnatal days to achieve the same weight as its contemporaries in the control treatment. However, this reduction in weight is not accompanied by reductions in morphometric measurements, demonstrating that the animals were lighter, but of equal size. In overnutrition, there is an increase in fetal weight in the second third of gestation. However, in the last third of the gestational period, there are no differences in fetal weight for the multiparous subgroup, but it was reduced in primiparous ewes. There are no effects of overnutrition on birth weight; however, this result is highly heterogeneous. Thus, maternal nutrition of ewe during pregnancy has effects on fetal and postnatal weight, but not on size. Furthermore, the effects of undernutrition are more homogeneous while overnutrition showed heterogeneous responses.

Milk yield and composition and body weight of offsprings of mixed-breed goats on semi-arid rangelands with different rainfall

The objective was to characterize milk yield and composition from mixed-breed goats kidding in winter and grazing rangelands with 221 (n = 15), 334 (n = 20), or 441 (n = 12) mm of annual rainfall in northern Mexico (22-25°N). Weekly milk yield and composition were recorded and progeny growth performance assessed. Body weight loss during lactation was the highest (6.4 kg) for goats on rangeland with 441 mm of rainfall than goats on 221 mm (1.6 kg), or 334 mm (1.8 kg; P < 0.01). The highest daily milk yield was for goats on 221 mm (498 mL; P < 0.01). There was not an evident peak of lactation and milk yield increased uninterruptedly at the end of lactation. Milk fat was negatively related to milk yield and goats on rangeland with 334 mm had the greatest milk fat content (P < 0.001). Milk protein and lactose content were higher in goats on rangeland with 221 mm (P < 0.01). Goat kids on rangelands with 221 and 441 mm grew faster and were heavier (P < 0.001) at weaning than kids reared in other rangelands. Weaning weight was positively related to milk yield (P < 0.001); but not milk components (P > 0.05). In conclusion, moderate milk yield of mixed-breed goats on rangeland is feasible with parturitions in winter, and milk yield is not affected by reduced annual precipitation in rangelands of northern Mexico. Offspring growth performance depends on maternal milk yield, but not milk composition. Nevertheless, slow growth to weaning of offspring had adverse effects on time to reach adequate market weight.

Examining the Effects of Whole Crop Wheat Silage on Ewe Performance during Late Gestation Compared to Traditional Grass Silage across Three Prolific Breed Types

Simple Summary

Nutrition of the ewe during late pregnancy can impact the subsequent performance of the ewe and her lambs. In indoor lambing systems, grass silage is the predominant forage used but is of sub-optimal quality. This study examined the potential of whole crop cereal silage when offered to one of three prolific breed types in late pregnancy. With the exception of reduced crude protein intake on the whole crop wheat silage diets, nutrient intake or ewe body reserves were not affected by forage type. However, ewes offered whole crop wheat silage-based diets produced smaller lambs. Mule ewes produced lower volumes of colostrum in the first 18 h after lambing reflecting a lower nutrient intake during late pregnancy. Maternal nutrition and breed type merit careful consideration in prolific sheep production systems to ensure lamb welfare and survivability are not compromised.

Abstract

Provision of adequate nutrient intake in late gestation of the ewe is an important determinant of dam and offspring performance. A 2 × 3 factorial design experiment examining two forage types, whole crop wheat silage (WCWS) or grass silage (GS) offered to one of three prolific breed types, (Belclare X, Lleyn X, Mule (Bluefaced Leicester × Blackface Mountain)), was conducted. Forage type had no impact on dry matter (DM) or metabolizable energy (ME) intake, body weight and body condition score change, or colostrum production (p > 0.05). Ewes offered WCWS had lower crude protein (CP) intake (p < 0.0001) and a lower combined litter weight (p < 0.05). Mule ewes consumed less DM, CP, (p < 0.05), and ME (p < 0.01) compared to Belclare X and Lleyn X ewes however, water intake per kg DM consumed did not differ with breed type (p > 0.05). Colostrum yield over the first 18 h postpartum was lower for Mule ewes compared to other breed types (p < 0.05). In conclusion, results from this study suggest nutrient concentration and balance as opposed to forage type is important for late gestation nutrition and breed type can impact feed intake and colostrum yield.

Intake of Spineless Cladodes of Opuntia ficus-indica During Late Pregnancy Improves Progeny Performance in Underfed Sheep

Simple Summary

Plants in the Opuntia genus are abundant and can be used as a feed supplement because they are highly digestible and can provide water and energy. We fed sheep during late gestation with alfalfa (Control), Opuntia (Opuntia) or protein-enriched Opuntia (E-Opuntia) and measured milk yield and postnatal growth in the progeny. Birth weight did not differ among treatments (p > 0.05) but progeny from E-Opuntia grew faster (p < 0.01) and were heavier at weaning (p < 0.05), despite the fact that Control ewes produced more milk (p < 0.05). Feeding ewes with Opuntia (protein enriched or not) during the last third of gestation is an option for reducing production costs in underfed females managed under extensive conditions in arid and semiarid regions.

Abstract

The present study tested whether feeding ewes during the last third of pregnancy with cladodes of Opuntia (untreated or protein-enriched), as an alternative to alfalfa hay, would improve milk yield as well as the pre- and post-natal growth of their lambs. Sixty mature Rambouillet ewes and their progeny were randomly allocated among three nutritional treatments: (i) Control, fed alfalfa; (ii) Opuntia, fed untreated cladodes; (iii) E-Opuntia, fed protein-enriched cladodes (pre-treated with urea and ammonium sulphate). Birth weight did not differ among treatments (p > 0.05) but Control ewes produced more milk than both groups of Opuntia-fed ewes (p < 0.05). However, milk yield was not related to the growth of the progeny (p > 0.05) because lambs from E-Opuntia-fed ewes grew faster (p < 0.01) and were heavier at weaning (p < 0.05) than lambs from the other two groups. We conclude that Opuntia (with or without protein enrichment) can be used as an alternative to alfalfa hay for feeding ewes during the last third of pregnancy and therefore reduce production costs under extensive conditions in arid and semiarid regions. Moreover, protein-enriched Opuntia appears to improve postnatal lamb growth.

Genome-wide association study of body weight and conformation traits in neonatal sheep

Sheep, an important source of meat, dairy products and wool, play an essential part in the global agricultural economy. Body weight and body conformation are key traits in the sheep industry; however, their underlying genetic mechanisms are poorly understood. In this study, a GWAS was implemented to identify promising genes possibly linked to birth weight (BW) and body conformation traits in neonatal sheep, using a high-throughput chip (630 K). After quality control, 277 individuals and 518 203 variants were analyzed using gemma software in a mixed linear model. A total of 48 genome-wide suggestive SNPs were obtained, of which four were associated with BW, four with withers height (WH), 11 with body length (BL) and 29 with chest girth (CG). In total, 39 genes associated with BW and body conformation traits were identified by aligning to the sheep genome (Ovis aries_v4.0), and most of them were involved in the cell cycle and body development. Promising candidate genes found included the following: FOS like 2 or AP-1 transcription factor subunit (FOSL2) for BW; potassium voltage-gated channel subfamily D member 2 (KCND2) for WH; transmembrane protein 117 (TMEM117), transforming growth factor beta induced (TGFBI), and leukocyte cell-derived chemotaxin 2 (LECT2) for BL; and trafficking kinesin protein 1 (TRAK1) and LOC101102529 for CG. These results provide cues for similar studies aiming at uncovering the genetic mechanisms underlying body development, and marker-assisted selection programs focusing on BW and body conformation traits in sheep.

Development of the central nervous system in equine twin fetuses derived by somatic cell nuclear transfer

Because of the growing importance of horses in leisure and several sports, somatic cell nuclear transfer (SCNT) is being used more frequently for cloning animals for performance and reproductive purposes. However, because of the need to perforate the zona pellucida during microsurgical reconstruction of the oocyte, it is possible that SCNT-derived embryos undergo premature hatching, resulting in embryo bisection and twinning. Therefore, because equine twin pregnancies often lead to abnormal embryo development and pregnancy failure, we performed a detailed comparative assessment of equine twin fetuses derived by SCNT with particular attention on the development of the central nervous system at 40 and 60 days gestation. The results of this study indicate that although cloned twin embryos show small differences in size, they do not exhibit apparent macro- or microscopic developmental discrepancies in the central nervous system, suggesting that the twining phenomenon resulting from SCNT does not affect fetal differentiation.

Transgenerational propensities for infant birth weight reflect fetal growth history of the mother in rhesus monkeys

Birth weight (BW) at delivery is an important developmental milestone indicative of prenatal conditions and portends of the postnatal growth trajectory that will occur during infancy and childhood. Previous research has documented that there are also many physiological and health consequences of being born either small-for-gestational age (SGA) or large-for-gestational age (LGA). Analyses of breeding animals have demonstrated further that a gravid female exerts a strong influence on the size of her infant by term, and this permissiveness or constraint over fetal growth can be transmitted from mothers to their daughters. The following research tested additional hypotheses about matrilineal effects on BW by examining records from a large breeding colony of rhesus monkeys across multiple generations. The analyses utilized BW of 1710 infant monkeys obtained over 4 decades. In addition to determining the association between the birth weight (BW) of a female and her own infants birthed later as a mother, the multi-generational transmission of birth size from a grandmother through her daughters to the next generation was examined. Other maternal influences were evident, including a progressive increase in infant BW with parity, which synergized with matrilineal effects across a female's reproductive life. In addition, our modeling indicated that if an infant's BW was discordant-a SGA female birthing a larger daughter-the discrepant fetal growth pattern could be accentuated in the next generation. Overall, the findings confirm that the size of an infant at term is significantly influenced by a type of gestational imprinting on daughters during the prenatal period, which then continues to shape birth outcomes in subsequent generations.

Relationship between fetal biometric assessment by ultrasonography and neonatal lamb vitality, birth weight and growth

Ultrasonographic examination of pregnant ewes can enable the identification of perinatal abnormalities and establish prenatal assistance responsible for minimizing morbidity and perinatal mortality. Therefore, we aimed to evaluate the feasibility of a fetal biometric analysis by ultrasonography to predict neonatal vitality and lamb growth during the first month of life. A longitudinal study was conducted with 13 healthy ewes, subjected to ultrasonographic examination every 15 days from 60^th day of pregnancy until lambing, evaluating thoracic diameter, abdominal diameter, biparietal diameter, humerus, femur and placentome length. At birth, 22 lambs were assessed through Apgar score at 5 minutes and after 1 hour. Measurement of body weight was also carried out immediately at birth and weekly during 30 days after birth. Thoracic diameter showed a significant increase between 91-105 days and 121-135 days. Conversely, abdominal diameter had a progressive growth until 106-120 days, and then, a steady development was observed. Biparietal diameter showed progressive growth only towards days 91 and 105. For the humerus length, we verified a significant increase between 106-120 days and 121-135 days, remaining unaltered onwards; while femur length continued to grow until lambing. The linear regression analysis between birth weight and biparietal diameter at 60-75 days was high (R²=0.96; P<0.0001; coefficient of variability of 3.3%). In conclusion, ultrasonographic analysis of fetal biparietal diameter at mid-pregnancy can be used as a predictor of lamb weight at birth. Moreover, assessment of femur length at final pregnancy can be employed for fetal and neonatal development estimation.

Shearing during late pregnancy increases size at birth but does not alter placental endocrine responses in sheep

Shearing during the latter half of pregnancy is a common practice to improve flock health and productivity. Previous studies have demonstrated that shearing pregnant ewes at mid or late pregnancy is associated with an increase in lamb birth weight. In the present study, we used singleton Polypay × Dorset pregnant sheep, to investigate the potential roles of placental function and changes in maternal metabolism in underlying this increased birth weight response. Two groups were randomly established and blocked at enrollment by animal BW, body condition score and subcutaneous adipose tissue depth. The groups were shorn (SH; n = 18) or not (C; n = 20) at gestational day (GD) 107 ± 1 (mean ± SEM). Weekly maternal plasma samples were collected between shearing and birth, but only six samples were assayed for progesterone, pregnancy-associated glycoproteins (PAG1), glucose and non-esterified fatty acids (NEFAs). At birth, sex, birth weight, and newborn body mass index (BMI) were recorded. Maternal BW during mid- to late-pregnancy was similar between groups. Shearing resulted in increased lamb birth weight and BMI (P < 0.05) regardless of fetal sex but did not affect the maternal concentration of PAG1 or progesterone from GDs 100 to 142. After shearing (GD100) and up to lambing, shorn females had higher circulating glucose concentrations (P < 0.05), but not NEFA, compared to the control group. Maternal circulating PAG1, progesterone, glucose or NEFA concentration across pregnancy did not differ according to lamb sex. Across pregnancy, birth weight was positively associated with PAG1 (P < 0.001), but not with progesterone concentrations. In conclusion, weight and BMI at birth were higher in both sexes upon shearing in singleton pregnancies. Despite PAG1 being associated with birth weight, late-pregnancy shearing did not alter the placental endocrine response. Whether other placental factors are altered upon shearing and may influence the increase in birth weight and BMI remain to be investigated.

Heritabilities for the puppy weight at birth in Labrador retrievers

Background

Weight at birth is an important predictor of neonatal mortality and morbidity in dogs. In addition, the birthweight of the puppies in a litter influences the decision to perform a cesarean section. The goal of the present study was to estimate heritabilities for the puppy birth weight in Labrador retrievers.

Results

Of the 1138 Labrador retriever litters whelped at the Guiding Eye for the Blind between September 2001 and February 2018, 1013 were included in the analyses after data editing. Puppy weight at birth was the target trait, measured on a continuous scale in pounds, and converted to grams. Linear mixed models were used to identify factors influencing puppy weight at birth. The analyses showed that the sex of the puppy, litter size, length of gestation, adult weight of the dam, parity, year of birth and inbreeding coefficient of the puppies and dams contributed to the variance of the puppy birth weight. Dam and litter effects were included as random effects. A multiple trait derivative free restricted maximum likelihood approach was used to estimate variance components and genetic parameters with two animal models, one without covariates (Model 1) and one with covariates (Model 2). Sex of the puppy and litter size had moderate effects, whereas gestation length, adult weight of the dam, parity, year of birth and inbreeding coefficients of the dam and the puppies had minor effects. Estimates for Model 1 and Model 2 were 0.21 and 0.17 for the direct heritabilities, 0.22 and 0.22 for the maternal additive genetic heritabilities, 0.07 and 0.07 for the maternal permanent environmental proportions, and 0.14 and 0.08 for the environmental proportion of the litter.

Conclusions

In order to estimate reliable breeding values for puppy weight at birth, sex of puppy, litter size, length of gestation and the adult weight of the dam should be included. Estimates could benefit from weighing the dams prior to each mating.

Treatment with Bumped Kinase Inhibitor 1294 Is Safe and Leads to Significant Protection against Abortion and Vertical Transmission in Sheep Experimentally Infected with Toxoplasma gondii during Pregnancy

Previous studies on drug efficacy showed low protection against abortion and vertical transmission of Toxoplasma gondii in pregnant sheep. Bumped kinase inhibitors (BKIs), which are ATP-competitive inhibitors of calcium-dependent protein kinase 1 (CDPK1), were shown to be highly efficacious against several apicomplexan parasites in vitro and in laboratory animal models. Here, we present the safety and efficacy of BKI-1294 treatment (dosed orally at 100 mg/kg of body weight 5 times every 48 h) initiated 48 h after oral infection of sheep at midpregnancy with 1,000 TgShSp1 oocysts. BKI-1294 demonstrated systemic exposure in pregnant ewes, with maximum plasma concentrations of 2 to 3 μM and trough concentrations of 0.4 μM at 48 h after each dose. Oral administration of BKI-1294 in uninfected sheep at midpregnancy was deemed safe, since there were no changes in behavior, fecal consistency, rectal temperatures, hematological and biochemical parameters, or fetal mortality/morbidity. In ewes infected with a T. gondii oocyst dose lethal for fetuses, BKI-1294 treatment led to a minor rectal temperature increase after infection and a decrease in fetal/lamb mortality of 71%. None of the lambs born alive in the treated group exhibited congenital encephalitis lesions, and vertical transmission was prevented in 53% of them. BKI-1294 treatment during infection led to strong interferon gamma production after cell stimulation in vitro and a low humoral immune response to soluble tachyzoite antigens but high levels of anti-SAG1 antibodies. The results demonstrate a proof of concept for the therapeutic use of BKI-1294 to protect ovine fetuses from T. gondii infection during pregnancy.

Pregnancy and Litter Size, But Not Lamb Sex, Affect Feed Intake and Wool Production by Merino-Type Ewes

Simple Summary

We examined whether feed intake and wool production are affected by pregnancy, litter size, or lamb sex on Merino genotype ewes. We observed that feed intake was influenced during pregnancy and lactation by litter size; whereas, wool production was influenced by litter size, but not by the sex of the lambs during pregnancy.

Abstract

Two experiments (Australia and Mexico) tested whether feed intake (FI) and wool production (WP) are affected by pregnancy (PRG), litter size (LZ), or lamb sex (LS) in Merino-type ewes. In Experiment-1, ewes were either not pregnant (NPR; n = 6), or carrying 1 (PR1; n = 7) or 3 (PR3; n = 11) fetuses, were studied in individual pens. NPR ewes had lower (p < 0.02) FI throughout PRG and lactation (LAC), except around lambing (p < 0.001). Following lambing, FI increased in PRG ewes (p < 0.001) to double the values in NPR ewes. PRG reduced WP (p < 0.001); in PR3, WP was lower than for both PR1 and NPR (p < 0.001). WP decreased during LAC and was lower in ewes rearing lambs than in NPR ewes (p < 0.001). Experiment-2 used 48 pregnant ewes (28 bearing singles and 20 bearing twins). Dam and lamb live weights (LW) and body condition (BC) were recorded from birth to weaning at 60 d, and dam fleece weight (DFW) was measured at weaning (12 months growth). WP was higher in ewes bearing and rearing single lambs than in ewes bearing twins (p < 0.001). DFW was positively (p < 0.01) related to LZ, dam LW, and BC, but not to changes in dam LW during LAC, or to lamb weight at birth or weaning, or LW gain, or LS. In conclusion, FI was affected during PRG and by LZ during LAC, whereas WP was influenced by LZ, but not LS, only during pregnancy.

Influence of Maternal Factors (Weight, Body Condition, Parity, and Pregnancy Rank) on Plasma Metabolites of Dairy Ewes and Their Lambs

Simple Summary

The present study assessed the effects of maternal parity, weight, body condition score (BCS), and pregnancy rank (single vs. multiple) on maternal metabolism during pregnancy and subsequent lactation, as well as on lamb birth weight, perinatal viability, and metabolism. The results highlight the relevance of appropriate nutritional management to maintain maternal BCS and offspring metabolism within physiological ranges, allowing sheep to face the metabolic challenges of lactation and pregnancy. Adequate nutrition and management reduce the influence of maternal factors on offspring phenotype.

Abstract

Pregnancy and lactation are challenging states that affect maternal and lamb health. In Lacaune dairy sheep, we evaluated the impact of parity, pregnancy rank, and body condition on body weight and the condition of ewes and lambs in mid-pregnancy (75 ± 5 d), in late pregnancy (142 ± 4d), and postpartum (52 ± 5d pp). Maternal age was associated with initial decreases, followed by increases, in body weight and condition. After lambing, both mature and maiden ewes lost weight and body condition. Maternal indices of glucose, protein, and lipid metabolism were within physiological values during pregnancy, but postpartum values depended on maternal parity and pregnancy rank, with multiple-pregnant ewes showing a postpartum increase in glucose and maiden sheep a postpartum increase in plasma cholesterol concentration. Male lambs were heavier than female lambs at birth, and lambs born to mothers with higher body condition scores were heavier. Lambs born as singletons were heavier than those born in litters. Maternal age and pregnancy rank did not influence lamb metabolic indicators. Sex affected plasma concentrations of glucose, triglycerides, and cholesterol. Maternal metabolic indicators showed minimal effects on lamb phenotype. These results suggest that, when appropriately fed, dairy sheep can cover the metabolic demands of pregnancy and milk production, regardless of age and pregnancy rank.

The effects of birth rank (single or twin) and dam age on the lifetime productive performance of female dual purpose sheep (Ovis aries) offspring in New Zealand

Greater rates of genetic gain can be achieved by selecting animals born to younger parents. However, little is known about the lifetime performance of dual purpose ewes (Ovis aries) that are born to primiparous ewe lambs (8 to 9 months old at breeding). This experiment investigated the effect of being born from either a ewe lamb or mixed age dam as either a single or twin on the lifetime performance of ewe progeny. Lifetime performance was measured in terms of the life time live weights of the ewes, the weight and number of lambs born and weaned, the efficiency of production (kilograms of lamb weaned / predicted pasture intake (kgDM) of the ewes), and ewe survival. The study followed the lifetime production of 17 single and 41 twin female lambs born to mature ewes (M1 and M2, respectively), and 28 single and 29 twin lambs born to ewe lambs (L1 and L2, respectively). Over their lifetime L2 ewes were lighter (P<0.05) but had similar body condition scores to the other three ewe groups. There was no difference in average progeny weaning weight or total progeny litter weaning weights between groups. The M1 ewes had the greatest longevity (P<0.05) of the four groups. Even though L2 ewes were lighter than the other three groups, this was insufficient to increase their lifetime efficiency of production (kg lamb weaned/predicted pasture consumption), relative to the other groups. These results suggest farmers could select replacements born to ewe lambs without sacrificing animal production.

Maternal Supplementation with Antioxidant Vitamins in Sheep Results in Increased Transfer to the Fetus and Improvement of Fetal Antioxidant Status and Development

Twinning and maternal nutritional restriction leads to fetal hypoxia, oxidative stress, and intrauterine growth restriction (IUGR) in near-term sheep pregnancies. Our aim was to determine the effect of oral supplementation of vitamins C and E in pregnant sheep on maternal and umbilical cord blood concentrations of vitamins C and E and the effects on fetal antioxidant status, growth, and placental efficiency. Sixteen single- and sixteen twin-bearing ewes, grazing natural Patagonian prairies, were selected after transrectal ultrasound at day 30 after mating. Half of ewes from each pregnancy rank were supplemented daily with vitamins C and E, administered orally, from 30 to 140 days of gestation, when maternal jugular and fetal venous cord blood samples were obtained during cesarean section. Fetuses were weighed and sexed. Placental weight in each fetus was also obtained. Blood plasma was harvested for measurements of maternal and fetal vitamins concentration and fetal antioxidant capacity. Maternal administration of vitamin C and E was associated with increased fetal cord levels of both vitamins, improved antioxidant status, and enhanced fetal growth in both singleton and twin pregnancies associated with increased placental efficiency. These results highlight the potential of vitamin C and E supplementation to reduce the impact of IUGR in both livestock and humans.

Investigation of relationship between vitamin D status and reproductive fitness in Scottish hill sheep

There is a growing interest in the influence of vitamin D on ovine non-skeletal health. The aim of this study was to explore the relationship between pre-mating vitamin D status, as assessed by serum concentrations of 25-Hydroxyvitamin D [25(OH)D; comprising D2 and D3] and subsequent reproductive performance of genetically unimproved Scottish Blackface (UBF), genetically improved Scottish Blackface (IBF) and Lleyn ewes kept under Scottish hill conditions. 25-Hydroxyvitamin D2 (25(OH)D2) and 25-Hydroxyvitamin D3 (25(OH)D3) concentrations were determined in serum samples harvested in November from ewes grazed outdoors. There were no significant differences in 25(OH)D2concentrations amongst the 3 genotypes. Lleyn ewes had significantly higher 25(OH)D3 and 25(OH)D concentrations than both Scottish Blackface ewe genotypes, whereas these vitamin D parameters did not differ significantly between the UBF and IBF ewes. Concentrations of 25(OH)D3 and 25(OH)D were positively associated with subsequent birth weights of singleton and of twin lamb litters. No significant associations between vitamin D status and number of lambs born or weaned per ewe were found. This study demonstrates that concentrations of cutaneously-derived 25(OH)D3, but not of orally consumed 25(OH)D2, differed between breeds. The positive association between ewe vitamin D status and offspring birth weight highlights the need for further investigations.