Colostrum Management for Dairy Calves

When to pair: Effects of different pairing ages on dairy calf health, behavior and performance

Pair housing presents an alternative to individual or larger group housing systems, though the effects of different pairing ages on calf welfare are not well understood. In this study, we examined the impact of pairing age on the performance, health, and behavior of dairy calves. A total of 140 Holstein female calves (n = 70 pairs) were used, paired at 3 ages: Early (6-7 d; 48 calves), Intermediate (29-30 d; 48 calves), and Late pairing (49-50 d; 44 calves). Calves were housed individually before pairing and weaned at 78 ± 2 d of age. Weight measurements were recorded at birth, 30, 50, 60 d, and at weaning. Calves' behavior was assessed 5 times per week through scan sampling after milk feedings from d 6-7 until weaning, and a food neophobia test was conducted at 50-51 d. Health assessments were performed 3 times per week by a veterinarian using Wisconsin clinical scores to diagnose diarrhea and BRD, with pulmonary ultrasonography at 55 d. The results suggest no association between pairing age and the prevalence of diarrhea or bovine respiratory disease (BRD), although our statistical power was limited. The number of calves with lung consolidation scores above 2 was also unaffected by pairing age. Early paired calves exhibited more exploration and play behaviors, and less idleness, stereotypies, and non-nutritive oral behaviors than Late paired calves. No differences were observed in cross-suckling likelihood across pairing ages. Early paired calves also showed a shorter latency to touch a novel feed in the food neophobia test, higher calf starter intake during the first 15 d, and greater ADG up to 50 d. Although overall ADG did not differ among pairing ages, Early paired calves were more homogeneous in weaning weight compared with Late paired calves. In conclusion, early pairing supports calves' initial development, promoting early feeding behavior and growth, enhancing behaviors associated with positive affective states, and without adverse effects on health or undesirable behaviors.

Genetic associations of colostrum yield with antibodies concentration and gross composition for selective breeding in Italian Holsteins

The quality of bovine colostrum, primarily determined by IgG concentration, is essential for the transfer of passive immunity and the development of the gastrointestinal tract in neonates. High IgG concentration in bovine colostrum (BC) is pivotal for the calf at first meal; however, while neonates often refuse to voluntarily drink the recommended amount of BC in the first hours of life, the dam frequently fails to produce a sufficient volume of colostrum at first milking. This study seeks to estimate the h2 of colostrum yield (CY) and its genetic correlations with total Ig, IgG, protein, and fat concentrations for the first time in the Italian Holstein population. Colostral Ig concentration and gross composition were assessed on individual samples collected using ad hoc near-infrared prediction models. The infrared-predicted traits along with the measured CY were used as phenotypes (n = 2,938) for the estimation of genetic parameters through linear animal models. Parity, photoperiod at calving, and classes of CY of the dam significantly impacted on the colostral composition, with parity having the most substantial influence. Colostrum of older cows, in fact, had greater total Ig, IgG, and protein concentrations than colostrum of younger cows. Colostral quality and CY were higher when calvings occurred in months with decreasing photoperiod. Also, CY was maximum in second-parity cows. Heritability estimates of IgG and total Ig concentrations were 0.225 ± 0.05 and 0.211 ± 0.05, approximately twice the h2 estimate for CY (0.101 ± 0.03). The correlation between CY and IgG concentration was positive (0.219 ± 0.032) at the phenotypic level and negative at the genetic level (-0.147 ± 0.190). Spearman rank correlations between EBV of the colostrum traits and official EBV/indexes for which there is selection ongoing in Italian Holstein breed were generally weak or moderate, and not always significant. Specifically, the CY was unfavorably associated with the PFT (production, functionality, and type; -0.300) and the IES index (economic health; -0.335), and IgG concentration was favorably linked to the official index for udder health/mastitis resistance (0.154) and fertility (0.166), mirroring those calculated for total Ig. Selection toward an intermediate optimum for CY at calving can be potentially pursued in the Italian Holstein breed through a balanced index without incurring additional costs for the IgG concentration.

Genetic and environmental determinants of immunoglobulin G in kid serum and adult colostrum of dairy goats

Immune competence is a key factor in the health and resilience of dairy ruminants. The aim of this study was to study IgG concentration in serum shortly after birth and in colostrum of lactating animals as proxy of passive immune transfer and colostrum quality, respectively, and thus provide new health and resilience indicators for selection. Data from 424 female kids and 203 primiparous goats, reared on an INRAE experimental farm, were analyzed. The IgG concentration was measured in kid serum and goat colostrum, respectively, using the radial immunodiffusion technique. Linear models were used to identify factors of variation in serum and colostrum IgG concentration, and health events were monitored for 5 wk after birth to measure the effect of passive immune transfer on kids' health. We found a significant effect of serum IgG level on hindquarters cleanliness score (as a proxy of digestive troubles) and nasal and ocular discharge. As expected, the absorption of IgG in the days following birth is essential to ensure the passive transfer of immunity from the mother to the youngster, and provide immune protection. Genetic parameters were estimated for serum IgG concentration in kids and for colostrum characteristics in primiparous goats. Heritability of serum IgG in kids was not significantly different from zero. This low value, with large SE, may be due to the limited sample size and large environmental variability likely not accounted for. Especially, we could not adjust for the amount of IgG that was ingested by the kid, which can have a significant effect on serum IgG and possibly on heritability estimates. Heritability of colostrum traits were moderate, with estimates of 0.25 (±0.16), 0.35 (±0.16), and 0.25 (±0.16) for IgG concentration, IgG mass, and colostrum volume, respectively. Genetic correlations with milk production showed high standard errors due to small numbers. However, estimates suggest a negative genetic association between production and IgG concentration in colostrum (genetic correlation = -0.44 ± 0.33), probably linked to a positive association with total colostrum volume. The significant heritabilities that were estimated for the first time demonstrate the existence of genetic control of colostrum quality in goats, and open up opportunities for selection in this species.

The effect of three different preservatives on the numbers and types of bacteria, Brix percentage, pH and nutritional composition of bovine colostrum sourced from New Zealand dairy farms

AIMS

To investigate the effect of preservation by addition of yoghurt starter, potassium sorbate and citric acid on counts of aerobic bacteria, Lactobacillus spp., Streptococcus thermophilus and coliforms, Brix percentage, pH, protein, fat and anhydrous lactose concentrations at 0, 7 and 14 days after collection for colostrum stored at ambient temperature.

METHOD

Approximately 2 L of first milking colostrum was collected from 10 farms in the Waikato region. Following mixing, it was split into five 400-mL sub-samples and allocated randomly to a control (two sub-samples), or treatment with yoghurt, potassium sorbate, or citric acid preservative. Throughout the trial samples remained in the laboratory at ambient temperature with the lids slightly ajar, and were stirred daily for 15-30 seconds using a sterile spatula. Sub-samples were tested on Days 0, 7 and 14. On Days 0 and 14 aerobic bacteria (by aerobic plate count (APC)), Lactobacillus spp., coliforms and Streptococcus thermophilus counts, pH, Brix percentage, protein, fat and anhydrous lactose were measured. On Day 7 only bacterial counts were completed.The data were analysed using non-parametric clustered bootstrap sampling to estimate the effect of treatment, time, and their interaction on the outcome variables.

RESULTS

Compared to control samples, on Day 7 the APC for potassium sorbate (1.0 (90% CI = 0.6-1.6) × 108 cfu/mL) was approximately seven-fold lower than for yoghurt (7.3 (90% CI = 4.1-11) × 108 cfu/mL), and approximately three-fold lower than citric acid (3.2 (90% CI = 0.2-4.3) × 108 cfu/mL) remaining low to Day 14. All preservatives reduced coliform growth compared to control samples at Day 7 but growth was lower for potassium sorbate than the other preservatives. For Lactobacillus spp., at Day 7, samples with yoghurt preservative had greater counts than the other two preservatives. Potassium sorbate reduced growth of S. thermophilus compared to the other treatments, especially at Day 7, with 7-10 times fewer S. thermophilus per mL compared to the other three groups. All groups showed an obvious acidification over time, with very little variation within days and treatment groups. There was no evidence for change in fat or protein percentage over time regardless of treatment.

CONCLUSION AND CLINICAL RELEVANCE

Aerobic and coliform bacteria proliferate extensively in unpreserved colostrum. All preservatives decreased coliform counts compared to un-preserved colostrum, but potassium sorbate was more effective at decreasing both coliforms and aerobic bacteria than either yoghurt or citric acid.

Forage sources in total mixed rations on rumen fermentation, gut fill, and development of the gastrointestinal tract of dairy calves

The inclusion of forage sources in calf diets is often discussed, and the main point debated is whether the inclusion level, particle size, source, and how forage is offered may impact gut fill and reduce body weight gain, as well as impact gastrointestinal tract development. This study aimed to determine the effects of feeding forage sources with different qualities on rumen fermentation, gut fill, and development of the gastrointestinal tract of dairy calves. Forty-eight Holstein dairy calves were blocked according to sex and body weight (BW) at 28 days of life and randomly assigned to 1 of 4 dietary treatments. Treatments consisted of a no-forage coarsely ground starter (CON) or total mixed rations containing 7.5% on DM basis of Tifton hay of either medium quality (MH) or low quality (LH) or 10% on DM basis of corn silage (CS). The nutritional content, including crude protein, NDF, lignin, and in vitro digestibility, was used as forage quality criteria. During the first 28 days of life, all calves received 3 L of whole milk twice daily, a commercial pelleted starter ad libitum, and no forage. After that, the solid diet was changed to the respective dietary treatments. Rumen samples were taken to determine rumen pH and volatile fatty acid (VFA) proportions. Calves were gradually weaned from 52 to 56 d of age, and 20 calves, 5 per treatment, were harvested two weeks after weaning. The anatomical parts of the gastrointestinal tract were weighed with and without contents, and histological analysis of rumen epithelium was conducted. The CON diet increased total VFA concentration compared to forage diets. The forage diets increased rumen pH, fecal pH, and gut fill. However, regardless of the source, the forage provision did not affect empty body weight. In addition, the forage provision increased the number of papillae in the rumen, but diets did not influence the length and width of papillae. The results suggest that 7.5% of Tifton hay, regardless of the quality, and 10% of corn silage in high-starch mixed diets benefit rumen health and promote greater gut fill without negative effects on final body weight.

Evaluation of factors associated with immunoglobulin, protein, fat and lactose concentrations in colostrum of dairy cows from Austria

BACKGROUND

Calves rely on the passive transfer with immunoglobulins derived from colostrum. Currently, there is a lack of knowledge on colostrum management practices and colostrum quality on small scale family-owned dairy farms in Austria. The objectives of this study were to describe factors that are associated with immunoglobulin, protein, fat and lactose concentrations in dairy cow colostrum from the federal state of Salzburg. Therefore, an online questionnaire was designed to gather information on general farm characteristics. Further, the farmers collected individual colostrum samples and completed a detailed accompanying questionnaire for each sample. Immunoglobulin levels were determined by using a Brix refractometer and protein, fat and lactose by standardized laboratory methods. Linear mixed effect models were built to test factors associated with colostrum immunoglobulin, fat, protein and lactose concentrations.

RESULTS

In total, 1,050 colostrum samples from 72 dairy farms were collected. The number of calvings per year was distributed as follows: ≤10 calvings: 8.3% of the farms, 11 to 20: 31.9%, 21 to 30: 29.2%, 31 to 40: 15.3% and ≥ 41 calvings: 15.3%. Overall, the median Brix value was 22.0% (7.3-36.1%). The number of samples with good and poor-quality colostrum was 517 and 528, respectively. Cow-level factors significantly affecting colostrum Brix% were parity, calving season, ante partum colostrum leakage, time lag between parturition and colostrum collection. In total, a subset of 307 colostrum samples from 39 farms from pure-breed dual-purpose Simmental cows were further analysed for protein, fat and lactose concentration. The median concentration for fat was 5.1% (0.5-18.5%), protein 14.6% (4.2-27.5%) and lactose 2.3% (0.2-5.0%). The cow-level factors affecting protein concentration were similar to the factors influencing Brix%. Fat concentration was influenced by the time lag between calving and colostrum collection and by parity.

CONCLUSIONS

The present study confirmed the factors, which are currently known to have an impact on colostrum quality. This was the first large scale approach in the federal state of Salzburg to survey colostrum management including colostrum sample collection. The range of colostrum quality was wide (7.3% Brix to 36.1% Brix) therefore many calves will be at risk of receiving poor quality colostrum as defined by a Brix of ≤ 22%.

Exploring Relationship Between Immunocompetence, HPA Axis Functioning and Performances of Preweaning Dairy Calves

Cortisol and DHEA(S) are markers of allostatic load and resilience; as such, they may be added to the definition of performance measures alongside immunocompetence. We aimed at studying the potential carryover effects of management practices on growth performances and the interrelationship between the hypothalamic-pituitary-adrenal (HPA) axis, immunocompetence and performances during the preweaning period in dairy calves. This study consisted of first a retrospective cohort study and second a prospective study. Calves had their growth performances and disease occurrence recorded, and their hair steroids (T1 at 20.03 ± 0.39 and T2 at 50.83 ± 0.41 days from birth) and plasmatic and colostral immunoglobulin G (IgG) was measured by immunoassays. The occurrence of preweaning diseases and the duration of individual housing negatively correlated to body weight (BW) at 60 days and the hair cortisol-to-DHEA(S) ratio (HC/HDHEA(S)) (T2) was negatively correlated to the daily weight gain (DWG) (-0.36; p < 0.05), plasmatic IgG (plaIgG) and the apparent efficiency of absorption (AEA) (-0.41; p < 0.01). Our results confirmed that the occurrence of diseases during the preweaning period and individual housing duration are pivotal for calves' growth. This prospective study highlighted a detrimental effect of allostatic load on immunocompetence and described a link between resilience and growth performances.

Effects of Vitamin and Mineral Supplementation During Gestation in Beef Heifers on Immunoglobulin Concentrations in Colostrum and Immune Responses in Naturally and Artificially Reared Calves

Two experiments assessed the effects of providing a vitamin and mineral supplement to gestating beef heifers on concentrations of immunoglobulins (Ig) in colostrum and calf serum 24 h after feeding maternal colostrum (Exp. 1) or a colostrum-replacement product (Exp. 2). Angus-based heifers (n = 31, Exp. 1; n = 14, Exp. 2) were fed a basal diet (CON) or were fed a basal diet plus a vitamin and mineral supplement (VTM) from breeding (Exp. 1) or 60 d pre-breeding (Exp. 2) through calving. Colostrum was collected at calving, and serum was collected from calves 24 h after colostrum consumption to evaluate passive transfer. Serum was collected from calves in Exp. 1 to determine serum titers in response to vaccination at birth, pasture turn out, weaning, and 14 d after vaccination. Concentrations of IgG, IgM, or IgA in colostrum or in calf serum at 24 h were not impacted by dam treatment (p ≥ 0.21); however, concentrations of Ig in calf serum at 24 h were greater (p ≤ 0.01) in calves receiving maternal colostrum than those receiving a colostrum replacer. Calves born to VTM heifers had greater antibody titers at birth, pasture turn out, and weaning for infectious bovine rhinotracheitis (IBR), bovine viral diarrhea virus type 2 (BVD-2), and bovine respiratory syncytial virus (BRSV), respectively. Our results suggest that the programming of immune function in calves via prenatal nutrition appears to extend postnatally in CON and VTM offspring.

Immediate dam-sourced colostrum provision reduces calf mortality - management practices and calf mortality in large dairy herds

BACKGROUND

Farm-specific management practices greatly impact calf mortality rates. This cross-sectional study aimed to analyse the association between calf mortality and management practices in large dairy farms. A total of 93 dairy farms were voluntarily included in the study. All farms reared their own youngstock, and all but one kept more than 100 dairy cows. From March 2017 to March 2018, calf management practices were monitored during a farm visit, and farm managers were surveyed regarding calving procedures, neonate management, and environmental factors. Data were collated and analysed in conjunction with the 2017 calf mortality rate, as determined for each farm by using data from the German database of animal origin and movement (HI-Tier). All variables from the topics of colostrum supply, calf feeding, housing, health related information and calving preparation of the cows that resulted in P ≤ 0.1 in the analysis of variance were assumed to be associated with the calf mortality rate and were considered for a general linear mixed regression model.

RESULTS

According to the data from the HI-Tier database of the 93 study herds from 2017, 54,474 calves were born alive and 3,790 calves died within the first six months of life. The calf mortality rate was lower on farms where calves were immediately provided with dam-sourced colostrum. Farm managers perceiving dust as the primary factor precipitating respiratory disease on the farm was positively associated with calf mortality. Regularly replacing bucket teats correlated with lower calf mortality rates compared to replacing them only upon detection of abrasion.

CONCLUSIONS

The study findings suggest that feeding calves with dam-sourced colostrum can potentially reduce overall calf mortality within the herd. This management practice holds comparable importance to ensuring successful passive transfer through timely and adequate colostrum feeding. Moreover, maintaining a low dust environment for the calves and consistently replacing bucket teats play significant roles in promoting better overall calf health.

Biosecurity Practices for Mycobacterium aviun subspecies paratuberculosis Infection, Salmonellosis, and Bovine Leukemia Virus on Cattle Operations

Mycobacterium avium subspecies paratuberculosis infection, salmonellosis, and bovine leukosis virus are important dairy and beef cattle diseases from a health perspective. For herds without infection, keeping the disease out through testing of source herds should be prioritized. For herds with infection, control programs should be instituted and followed to reduce the prevalence and ultimately eliminate the disease.

Biosecurity Strategies for Optimization of Calf Health in North American Beef and Dairy Operations

As the operations we serve continue to evolve, it will be essential to safeguard calf health to optimize future productivity in the beef and dairy industries. Veterinarians serve a critical role of educating producers and overseeing worker training protocols by communicating consistent messaging on the importance of biosecurity. Managing biosecurity for calves within the beef industry will always be directly impacted by the pathogen exposure from new additions to the herd, shared grazing sites, fomites, and environmental factors. Effective quarantine strategies for new cattle and contact between cattle of various ages will be crucial for protecting future calf performance.

Risk factors for omphalitis in neonatal dairy calves

Knowledge about potential risk factors for animal health is crucial to achieve animal welfare. The aim of this study was to provide practical guidance for farmers to improve the health status of their youngstock by identifying and eliminating risk factors for omphalitis in neonatal calves. A cross-sectional study including 3,445 dairy calves from 567 farms located in three structurally different regions of Germany was performed from December 2016 to July 2019. On each farm calves aged five to 21 days underwent clinical examinations with special consideration of the umbilicus for signs of inflammation. Information regarding animal health, hygiene, and management was obtained via interviews with the farmers. Rearing conditions were recorded following visual inspection using written standard operating procedures. Multifactorial statistical analyses were performed to identify potential risk factors for omphalitis on animal and farm level. The overall omphalitis prevalence in calves aged five to 21 days was 30.9%. Across all regions and farms, every fourth calf per farm exhibited signs of omphalitis (median farm prevalence: 25.0%, interquartile range: 0.0-50.0%). According to the farmers, however, only 4.5% of the calves had been treated for omphalitis in the preceding 12 months. Risk factors for omphalitis identified included the dampness of the lying area in the first 2 weeks of life, a body condition score of the dam after calving outside the optimal range, and the time that calves spent with their dam after birth. Calves on farms providing dry lying areas in the first 2 weeks of life had 0.77 times the risk of omphalitis compared to calves on farms with predominantly damp bedding. When the dams were judged under- or over-conditioned after calving, their offspring had a 1.4 times higher omphalitis risk, respectively, compared to calves from dams optimal conditioned. Calves from farms separating calf and dam beyond 12 h after birth were 0.75 times as likely to develop omphalitis than calves from farms performing immediate separation. These results highlight the complexity of multifactorial diseases such as umbilical infection. The evidence presented can help to establish guidelines for dairy farmers to improve the umbilical health of their calves.

Impact of prenatal heat tolerance in holstein dry cows on their calves' thermoregulation and immunity

This study examines the impact of Holstein dry cows' prenatal heat tolerance (n = 180) on their calves' thermoregulation and immunity. Holstein cows (body condition score 3.29 ± 0.39, parity 2.64 ± 0.79) were monitored for body temperature (BT), respiratory rate (RR), and microenvironmental temperature and humidity twice daily for seven days during heat stress. Mixed-effects model and cluster method identified heat-tolerant (n = 68) and heat-sensitive (n = 114) dry cows. Once cows gave birth, the RR and BT of 2-day-old calves were recorded every 2 h for two days, totaling five measurements per day, to assess thermoregulatory responses using generalized linear mixed models. Calves in the heat-tolerant group had a better thermoregulatory response than the heat-sensitive group, RR of heat-tolerant calves was significantly higher than the heat-sensitive calves (P = 0.02). Plasma indicators were analyzed to assess calf immunity. Heat-tolerant calves had significantly lower plasma cortisol, tumor necrosis factor-alpha, interleukin 2, interleukin 4, interleukin 6, and interleukin 10 concentrations compared to heat-sensitive calves (P < 0.05). In both cows and calves, plasma cortisol concentrations in the heat-tolerant groups were lower than those in heat-sensitive groups. In comparison, plasma heat shock protein 70 and heat shock protein 90 concentrations were higher (P < 0.05). In conclusion, calves born to heat-tolerant cows had higher thermoregulation and immunity than calves born to heat-sensitive cows when exposed to heat stress.

Cross-sectional study investigating the components and quality of colostrum and colostrum replacement products fed to Ontario dairy goat kids

Colostrum replacement products (CRP) for use in goat kids are sourced from bovine colostrum and often used by producers to supplement or replace maternal colostrum to prevent infections. To compare the CRP fed on farm to caprine colostrum a cross-sectional study was undertaken. Ontario dairy goat producers were asked to collect first milking colostrum from their goats and samples of the reconstituted commercial replacement product currently in use. The frozen samples were thawed and submitted for testing of fat, protein, and lactose content, IgG1 concentration, and aerobic bacterial culture. Compared with caprine colostrum, the reconstituted replacement products were lower in protein (11.7%), and fat (4.6%) and higher in lactose (5.4%) on average. The average IgG1 concentration in goat colostrum (53.5 g/L; range: 16.6-1,985.8) was significantly higher than in CRP (33.7 g/L; range: 10.7-55.3). The Brix cut point for good quality goat colostrum (50 g/L) was calculated at 23% (sensitivity = 69.6%, specificity = 88.0%) for goat colostrum and 26% for the CRP (sensitivity = 87.5%, specificity = 100%). The average aerobic bacteria count for goat colostrum was lower (2.95 log10 cfu/mL) than the CRP samples that were cultured (3.85 log10 cfu/mL). Further investigation into CRP, including on-farm storage of opened powdered product and mixing and storage of reconstituted product, is warranted. Variability in the levels of IgG1; aerobic bacterial growth; and fat, protein, and lactose content in CRP also requires further exploration to determine their effects on kid health.

Evaluation of serum concentrations of total protein and gamma-globulin as an indicator of serum immunoglobulin G concentration in dairy calves

The aim of this study was to evaluate precision of estimating serum IgG concentration from total protein (TP) or gamma-globulin (γGLB) concentration as an alternative approach, and to compare morbidity of preweaning dairy calves differing in serum γGLB concentration. In trial 1, blood was sampled from 129 Holstein calves in the first week after birth, and serum concentrations of TP, γGLB, and IgG were measured. Spearman's correlation coefficient (rs) between serum IgG and TP concentrations was 0.89, and rs between serum IgG and γGLB concentrations was 0.96. Absolute residual (observed - predicted) serum IgG concentrations were smaller when estimated by serum γGLB concentration than by serum TP concentration, and differences in the absolute residuals were smaller for calves fed colostrum replacer (1.68 vs. 4.29 g/L) than those fed whole colostrum (2.41 vs. 3.48 g/L). In trial 2, blood was sampled from 740 Holstein heifer calves during the first week of age, and serum γGLB concentration was measured. The calves were divided into 4 categories based on their serum γGLB concentration; ≥1.0 g/dL (excellent), 0.7 ≤ γGLB <1.0 g/dL (good), 0.4 ≤ γGLB <0.7 g/dL (fair), and <0.4 g/dL (poor). Morbidity for diarrhea and respiratory disease in preweaning dairy calves was determined for the first 28 and 56 d of age, and compared among the 4 categories based on serum γGLB concentration. Calves with serum γGLB concentration higher than 0.7 g/dL (good and excellent) had less diarrhea during the first 28 d of age than those with lower serum γGLB concentration (fair and poor). Calves with serum γGLB concentration higher than 1.0 g/dL (excellent) had less respiratory diseases for the first 56 d of age than those with lower serum γGLB concentration (good, fair, and poor). These results suggest that serum IgG concentration can be estimated more precisely from concentration of γGLB than TP particularly for calves fed colostrum replacer, and that γGLB concentrations in the first week of age are associated with morbidity of calves. Transfer of passive immunity in dairy calves can be assessed effectively by serum γGLB concentration.

Nutritional and health effects of bovine colostrum in neonates

High concentrations of immunoglobulins, bioactive peptides, and growth factors are found in bovine colostrum (BC), the milk produced by cows in the first few days after parturition. Various biological functions make it increasingly used to provide nutritional support and immune protection to the offspring of many species, including humans. These biological functions include cell growth stimulation, anti-infection, and immunomodulation. The primary components and biological functions of colostrum were reviewed in the literature, and the authors also looked at its latent effects on the growth and development of neonates as well as on conditions such as infections, necrotizing enterocolitis, short bowel syndrome, and feeding intolerance. The importance of BC in neonatal nutrition, immune support, growth and development, and gut health has been demonstrated in a number of experimental and animal studies. BC has also been shown to be safe at low doses without adverse effects in newborns. BC supplementation has been shown to be efficient in preventing several disorders, including rotavirus diarrhea, necrotizing enterocolitis, and sepsis in animal models of prematurity and some newborn studies. Therefore, BC supplementation should be considered in cases where maternal milk is insufficient or donor milk is unavailable. The optimal age, timing, dosage, and form of BC administration still require further investigation.

Innovating Beef Cattle Veterinary Practices: Leveraging Genetic and Genomic Tools

In the evolving landscape of beef cattle management, veterinarians are transitioning from their traditional role of treating diseases to becoming proactive advisors. This article explores how veterinarians with knowledge of genetic tools are poised to be vital in addressing the fundamental industry challenges. It highlights the role of genetic selection in reducing calving difficulties, emphasizing its benefits for animal health and welfare. The article also surveys the genomic technologies available and discusses the importance of integrating these insights with veterinary expertise to support informed decisions in selection, mating, and marketing strategies.

Comparison of radial immunodiffusion, turbidimetric immunoassay, and Brix refractometry for determining bovine colostrum quality

Determining the concentration of IgG in colostrum is critical for assessment of colostrum quality. On-farm use of a Brix refractometer to estimate colostrum IgG concentration is widespread, whereas radial immunodiffusion (RID) is the laboratory reference method. Turbidimetric immunoassay (TIA) might offer an alternative method to quantify IgG in colostrum, but the agreement with RID, as well as critical thresholds to determine high-quality colostrum, remain uncertain. The objective of this study was to determine the level of agreement between RID, Brix %, and TIA for evaluation of colostrum quality. Composite colostrum samples (n = 58) from Holstein cows were evaluated using a digital Brix refractometer at the time of collection and stored at -20°C until analysis. The concentration of IgG was determined using RID and TIA. Data were analyzed using Passing-Bablok regression and Bland-Altman plots. Critical thresholds for TIA and Brix measurements to identify colostrum with an IgG concentration ≥50 and ≥100 g/L based on the reference method were determined using logistic regression and receiver operating characteristic curves. Results revealed that both TIA (Kendall's τ = 0.91) and Brix % (τ = 0.78) had a strong correlation with RID. Passing-Bablok regression identified a systematic (6.91 [4.33 to 8.98] g/L) and proportional (0.69 [0.67 to 0.72] g/L) bias between RID and TIA. The optimum thresholds to identify samples with an IgG concentration ≥50 and ≥100 g/L were 40.6 g/L (area under the curve [AUC]: 1.0; sensitivity (Se): 100; specificity [Sp]: 100) and 85.8 g/L (AUC: 0.99; Se: 96.6; Sp: 96.6) for TIA and 18.4% (AUC: 1.0; Se: 100; Sp: 100) and 25.8% (AUC: 0.99; Se: 82.8; Sp: 93.1) for Brix %, respectively. Using the identified thresholds, our results show that both Brix and TIA were highly accurate for identifying high-quality colostrum, but because of a proportional bias, direct comparison of IgG concentration results obtained by RID and TIA are cautioned.

Survey on colostrum management by German dairy farmers focusing on frozen colostrum storage

Because calves are born with low levels of antibodies, effective colostrum management is one of the most critical factors for successful calf rearing. A timely and adequate supply of sufficiently high-quality colostrum immediately after birth is essential to ensure the passive immunization of calves. Frozen colostrum reserves are recommended to fulfill the immunological and nutrient requirements of newborn calves, even in exceptional situations; however, the implementation rates on German dairy farms and challenges of realization remain unclear. A 33-question online survey, focused on frozen colostrum reserves, was developed to obtain an overview of colostrum management practices on German dairy farms. The questionnaire was divided into 3 sections: (1) personal data; (2) farm characteristics; (3) colostrum management. Of the 155 responses we received, 63.9% were from female farmers, and 35.5% were from male farmers. Conventional farming was practiced on 89.0% of farms, and organic farming was practiced on 7.1% of farms. Of the respondents, 89.0% froze colostrum. The main reasons for freezing colostrum were (1) the dam does not produce enough colostrum; (2) the dam cannot be milked; or (3) the dam died during birth. Farmers primarily froze colostrum from cows during their third to fifth lactation. Before freezing, 33.1% of the respondents measured indicators in the colostrum to estimate Ig concentrations, whereas 2.3% determined the colostrum quality after freezing. Reusable and disposable polyethylene terephthalate deposits (23.1%, 22.3%) and colostrum bags (20.0%) were the primary containers used to freeze colostrum. The main reasons for not freezing colostrum were the high labor intensity and the availability of fresh colostrum from other cows. Thawing methods included buckets (47.7%) and professional water baths (13.8%). The survey identified areas in which improved knowledge transfer could enhance colostrum management. Furthermore, there appeared to be a lack of specific, feasible instructions for employees concerning the practical implementation of colostrum management. Most importantly, the regular determination and documentation of immunoglobulin concentrations should be emphasized. The added value of stored colostrum, relative to a greater workload, should also be promoted, particularly on smaller farms.

Effect of Blood Sampling Time After Colostrum Intake on the Concentration of Metabolites Indicative of the Passive Immunity Transfer in Newborn Dairy Calves

Due to the synepitheliochorial placental structure, bovines show no maternal antibody flow from mother to fetus during pregnancy, resulting in an agammaglobulemic newborn [...].

Herd-Level Risk Factors Associated with Mycoplasma bovis Serostatus in Youngstock on Irish Dairy Farms

Mycoplasma bovis is a globally significant pathogen of cattle associated with a wide range of clinical syndromes, including respiratory disease, mastitis, arthritis, otitis, and reproductive failure. Since its detection in Ireland in 1994, M. bovis has become a significant contributor to morbidity and mortality in Irish cattle. This study aimed to investigate herd-level risk factors associated with M. bovis seropositivity in replacement dairy heifers, using data from 105 Irish dairy herds. Ten heifers per herd were sampled on three occasions: spring 2018, spring 2019, and autumn 2019. Seropositivity was evaluated using two thresholds: ≥1 positive heifer (Model ≥ 1POS) and ≥3 positive heifers (Model ≥ 3POS). M. bovis seropositivity varied over time, with at least one positive heifer in 50.4% (95% confidence interval (CI): 40.5-60.3) of herds in spring 2018, 35.2% (95% CI: 26.2-45.1) in spring 2019, and 45.7% (95% CI: 36.0-55.7) in autumn 2019. Herds with three or more positive heifers increased from 31.4% (95%CI: 22.7-41.2) in spring 2018 to 42.9% (95% CI: 33.2-52.9) by autumn 2019. Risk factors for M. bovis seropositivity included the purchase of cattle, which significantly raised the odds of seropositivity across multiple visit periods (Model ≥ 1POS: Odds ratio (OR) 3.84, p = 0.02; Model ≥ 3POS: OR 3.69, p = 0.02). Managing more than three land parcels, housing heifer calves separately from bull calves, and sharing airspace between calves and older animals also increased seropositivity risks. Conversely, more colostrum feeds reduced the risk of seropositivity (Model ≥ 1POS: OR 0.81, p = 0.05), while colostrum quality assessment and feeding waste milk showed a trend toward increased risk. These findings suggest the importance of robust biosecurity measures, including limiting cattle purchases, improving calf management, and enhancing colostrum feeding practices, to control the spread of M. bovis. This study provides valuable insights into the epidemiology of M. bovis in Irish dairy herds, emphasising the need for targeted biosecurity and surveillance to safeguard herd productivity.

Sensitivity of dairy calf Salmonella enterica serotype Cerro isolates to infection-relevant stressors

Salmonella enterica serotype Cerro (S. Cerro) is an emerging Salmonella serotype isolated from cattle, but the association of S. Cerro with disease is not well understood. While comparative genomic analyses of bovine S. Cerro isolates have indicated mutations in elements associated with virulence, the correlation of S. Cerro fecal shedding with clinical disease in cattle varies between epidemiologic studies. The primary objective of this study was to characterize the infection-relevant phenotypes of S. Cerro fecal isolates obtained from neonatal calves born on a dairy farm in Wisconsin, USA. The S. Cerro isolates varied in biofilm production and sensitivity to the bile salt deoxycholate. All S. Cerro isolates were sensitive to sodium hypochlorite, hydrogen peroxide, and acidic shock. However, S. Cerro isolates were resistant to nitric oxide stress. Two S. Cerro isolates were unable to compete with S. Typhimurium during infection of calf ligated intestinal loops, indicating decreased fitness in vivo. Together, our data suggest that S. Cerro is sensitive to some innate antimicrobial defenses present in the gut, many of which are also used to control Salmonella in the environment. The observed phenotypic variation in S. Cerro isolates from a single farm suggest phenotypic plasticity that could impact infectious potential, transmission, and persistence on a farm.IMPORTANCESalmonella enterica is a zoonotic pathogen that threatens both human and animal health. Salmonella enterica serotype Cerro is being isolated from cattle at increasing frequency over the past two decades; however, its association with clinical disease is unclear. The goal of this study was to characterize infection-relevant phenotypes of S. Cerro isolates obtained from dairy calves from a single farm. Our work shows that there can be variation among temporally related S. Cerro isolates and that these isolates are sensitive to killing by toxic compounds of the innate immune system and those used for environmental control of Salmonella. This work contributes to our understanding of the pathogenic potential of the emerging pathogen S. Cerro.

Investigating the IgM and IgG B Cell Receptor Repertoires and Expression of Ultralong Complementarity Determining Region 3 in Colostrum and Blood from Holstein-Friesian Cows at Calving

In cattle, colostral maternal immunoglobulins and lymphocytes transfer across the neonate's intestinal epithelium to provide protection against pathogens. This study aimed to compare repertoires of B cell populations in blood and colostrum in cows for the first time, with an emphasis on ultralong complementarity determining region 3 (CDR3, ≥40 amino acids). Blood mononuclear cells (BMCs, n= 7) and colostral cells (n = 7) were isolated from Holstein-Friesian dairy cows. Magnetic-activated cell sorting was used to capture IgM and IgG B cells from BMCs. Colostral cells were harvested by centrifugation. RNA was extracted and cDNA was produced; IgM and IgG transcripts were amplified using polymerase chain reactions. Amplicons were sequenced using the Nanopore Native barcoding kit 24 V14 and MinION with R10.4 flow cells. In colostrum, there was a significantly greater percentage of IgM B cells with ultralong CDR3s (8.09% ± 1.73 standard error of the mean) compared to blood (4.22% ± 0.70, p = 0.05). There was a significantly greater percentage of IgG B cells in colostrum with ultralong CDR3s (12.98% ± 1.98) compared to blood (6.61% ± 1.11, p = 0.05). A higher percentage of IgM and IgG B cells with ultralong CDR3s in colostrum may be indicative of a potential role in protecting the neonate.

Association of different classifications of hypocalcemia with quantity and quality of colostrum, milk production, and health of Holstein dams and their calves

The aim of the present study was to assess the effect of serum calcium (Ca) status in the early postpartum period on the quantity and quality of colostrum, milk production, and the health of Holstein dams and their calves. One hundred multiparous Holstein cows were enrolled in this study. To determine serum Ca status, blood samples were taken at 1 and 4 days in milk (DIM). Cows were categorized into 1 of 4 groups based on their serum Ca concentrations: normocalcemic (CON; Ca >1.87 at 1 DIM and >2.10 mmol/L at 4 DIM, n = 36), transient SCH (TSCH; Ca ≤1.87 at 1 DIM and >2.10 mmol/L at 4 DIM, n = 14), persistent SCH (PSCH; Ca ≤1.87 at 1 DIM and ≤2.10 mmol/L at 4 DIM, n = 15), or delayed SCH (DSCH; Ca >1.87 at 1 DIM and ≤2.10 mmol/L at 4 DIM, n = 35). The ROC curve was utilized to determine the optimal cut-off value for serum total Ca, maximizing both sensitivity and specificity in predicting metritis. Metabolic disorders such as dystocia, retained placenta, and culling within 60 DIM were not affected by serum Ca status in the early postpartum period (P > 0.10). However, the incidences of metritis and endometritis were different based on the serum Ca status of the cows. The PSCH cows had a higher incidence of metritis than the CON cows (P = 0.05). Also, the DSCH cows tended to have an increased risk of metritis than the CON cows (P = 0.09). However, metritis incidence in the TSCH and CON cows was similar (P = 0.83). Cows with PSCH (P = 0.07) and DSCH (P = 0.10) tended to be at a higher risk for endometritis than the CON cows. But, the incidence of endometritis in the TSCH and CON cows was not different (P = 0.50). The TSCH cows had higher milk yield than the PSCH and DSCH cows (P = 0.05). However, milk yield was not different between the TSCH and CON cows and the PSCH and DSCH and CON cows. The serum Ca status of cows had no effect on colostrum volume and its quality, age and weight of weaning, and average daily gain of calves (P > 0.10). The proportion of calves experiencing failure of passive transfer (FPT) was greater in the PSCH group than in the CON group (P = 0.03). Also, the FPT tended to be higher in the DSCH calves compared to the CON calves (P = 0.10). However, the FPT in the TSCH and CON calves was not different (P = 0.83). The incidence of diarrhea tended to be higher in the PSCH and DSCH calves compared to the CON calves (P = 0.10). However, diarrhea incidence between the TSCH and CON calves was similar (P = 0.97). Overall, the findings of this study suggest that cows with TSCH showed better adaptation to lactation, experienced a lower occurrence of diseases and produced higher milk compared to PSCH and DSCH cows. Furthermore, despite the similar quantity and quality of colostrum across all groups, the PSCH and DSCH groups displayed a greater proportion of calves experiencing FPT and diarrhea in comparison to the TSCH group.

An Expert Consensus Study Regarding Management Practices to Prevent Infectious Mortality in Preweaned Beef Calves in Western Canada

Disease prevention is a cornerstone of herd management for minimizing preweaning calf mortality. However, scientific evidence about the usefulness of practices in herds is scarce. The first objective was for a group of veterinarians to determine which practices are most useful considering their effectiveness, ease of implementation, and economic feasibility. A second objective was for them to define which practices should be included in a tool to facilitate discussions between producers and veterinarians. Expert opinions and consensus were determined using a modified Delphi approach. During two questionnaire rounds, participants scored the effectiveness, ease of implementation, and economic feasibility of each practice. Overall scores for each practice were calculated, and feedback reports were sent to participants between rounds showing the groups' median responses. Consensus on which practices should be included in the tool was targeted during the workshops. Twelve veterinary experts participated. Administering clostridial vaccines and providing calves with colostrum in case they had not nursed were considered practices that were 'always useful for all herds'. However, most practices had intermediate levels of usefulness, and among these, antibiotics were considered the least useful. Nevertheless, all practices discussed during the workshops attained a consensus about being included in the future tool to facilitate on-farm discussions.

Effect of oxytocin use during colostrum harvest and the association of cow characteristics with colostrum yield and immunoglobulin G concentration in Holstein dairy cows

Our objectives were to determine the effect of oxytocin use during colostrum harvest on colostrum yield and IgG concentration in Holstein dairy cows on a commercial dairy in New York and to describe associations of cow characteristics with these outcomes. Animals were enrolled between July and October 2023 using a randomized block design, with day of enrollment as the unit of randomization. A median (range) of 10 (3-19) cows were enrolled per day. Treatments were (1) 40 IU oxytocin (OXY40), (2) 20 IU oxytocin (OXY20), and (3) an untreated control group (CNTR). Oxytocin was administered i.m. ∼45 s before unit attachment in a rotary parlor. Colostrum weight was measured using the colostrum bucket-embedded scale or a platform scale when the yield was less than the smallest bucket scale. The concentration of IgG ([IgG]) in colostrum was determined using radial immunodiffusion and used to calculate total IgG, and DM (%) was determined by oven drying. Individual cow characteristics such as parity, calf sex, weight, dystocia score, stillbirth, and milk production in wk 4 of lactation; additionally, for multiparous cows, dry period length and previous lactation dry-off linear SCS were collected. Data were analyzed separately for primiparous and multiparous cows using backward stepwise elimination. To produce final mixed effects ANOVA models, primiparous cows (n = 201) were randomized to 35.8% (n = 72) OXY40, 32.8% (n = 66) OXY20, and 31.3% (n = 63) CNTR. Multiparous groups (n = 435) were randomized to 34.7% (n = 151) OXY40, 29.7% (n = 129) OXY20, and 35.6% (n = 155) CNTR. The median (range) colostrum yield was 6.0 (0-20.6) kg and [IgG] was 98.5 (0.1-293.6) g/L in the study population. In primiparous cows, OXY40 had a higher colostrum yield (LSM [95% CI]) of 5.4 (4.9-5.9) kg compared with both OXY20 (4.1 [3.5-4.7] kg) and CNTR (3.8 [3.3-4.3] kg). In multiparous cows, OXY40, OXY20, and CNTR did not differ in colostrum yield (5.9 [5.3-6.5], 5.7 [5.1-6.3], and 5.4 [4.8-6.0] kg, respectively), but colostrum yield was greater in parity 2 compared with all other parities, cows giving birth to male calves, cows with the highest milk production at wk 4 of lactation, and cows with a dry period of >65 d. Oxytocin use did not affect [IgG] in either primiparous or multiparous cows, but [IgG] was highest in cows in parity ≥4 and lowest in cows dry >65 d. In summary, oxytocin use at 40 IU i.m. was associated with a higher colostrum yield in primiparous cows only and no change in [IgG]. Oxytocin use likely addressed disturbed milk ejection and therefore increased colostrum yield in heifers milked for the first time in a rotary parlor. This study confirms cow characteristics associated with colostrum production within a single herd.

Comparative Analysis of Angora Rabbit Colostrum and Mature Milk Using Quantitative Proteomics

Colostrum intake is a crucial determinant of survival in newborn rabbits. Neonates rely entirely on passive immunity transfer from their mothers while suckling colostrum. The goal of this study was to explore the protein differences of rabbit milk during different lactation periods. Our findings showed that the daily milk yield exhibited an increasing trend from the 2nd to the 21st day of lactation. A data-independent acquisition proteomics approach identified a total of 2011 proteins. Significantly, different abundances were found for 525 proteins in the colostrum and the mature milk samples. Eleven differentially abundant proteins (DAPs) were examined using parallel reaction monitoring, which verified the reliability of the proteomic data. Gene Ontology analysis revealed that these DAPs were primarily associated with glycosyltransferase activity, macromolecule transmembrane transporter activity, and regulation of acute inflammatory response. The dominant metabolic pathways of the DAPs involve the complement and coagulation cascades. A protein-protein interaction analysis identified apolipoprotein B, apolipoprotein A1, triose phosphate isomerase 1, and albumin as the hub proteins responsible for distinguishing differences between biological properties in rabbit colostrum and mature milk. These findings enhance our comprehension of the rabbit milk proteome, particularly in expanding our knowledge regarding the requirements of neonatal rabbits.

Associations among antimicrobial use, calf management practices, and antimicrobial resistance in Escherichia coli from a pooled fecal sample in calves on Canadian dairy farms: A cross-sectional study

The objective of this cross-sectional study was to determine associations between calf management practices, the number of antimicrobial treatments, and antimicrobial resistance in preweaning heifers on Canadian dairy farms. A composite of 5 fecal samples from preweaning calves was collected from 142 dairy farms in 5 provinces and analyzed for phenotypic antimicrobial susceptibility with the microbroth dilution method. Questionnaires were used to capture herd characteristics and calf management practices used on the farm. Calf treatment records were collected during the farm visits. Escherichia coli was isolated from all 142 fecal samples with the highest resistance to tetracycline (41%), followed by sulfisoxazole (36%), streptomycin (32%), chloramphenicol (28%), ampicillin (16%), trimethoprim-sulfamethoxazole (15%), ceftriaxone (4.2%), cefoxitin (2.8%), amoxicillin-clavulanic acid (2.1%), ciprofloxacin (2.1%), nalidixic acid (2.1%), azithromycin (1.4%), and gentamicin (1.4%). Multidrug resistance was observed in 37% of E. coli isolates. Three-quarters of farms used fresh colostrum as the most common type of colostrum fed to calves. Colostrum quality was checked on 49% of farms, but the transfer of passive immunity was only checked on 32% of farms in the last 12 mo. Almost 70% of farms used straw or hay or a combination as the bedding material for calves. Among the 142 farms, a complete set of calf records were collected from 71 farms. In a multivariable logistic regression model, farms with ≥1.99 to 32.57 antimicrobial treatments/calf-year were 3.2 times more likely to have multidrug resistant E. coli in calf feces compared farms with <1.99 antimicrobial treatments/calf-year. Farms using hay or straw beddings were 5.1 times less likely to have multidrug resistant E. coli compared with those with other bedding materials including shavings or sawdust. Bedding management practices on farms may need to be investigated to reduce the potential effect on disseminating multidrug resistant bacteria.

The ability of a handheld near-infrared spectrometer to do a rapid quality assessment of bovine colostrum, including the immunoglobulin G concentration

Portable infrared-based instruments have made important contributions in different research fields. Within the dairy supply chain, for example, most of portable devices are based on near-infrared spectroscopy (NIRS) and are nowadays an important support for farmers and operators of the dairy sector, allowing fast and real-time decision-making, particularly for feed and milk quality evaluation and animal health and welfare monitoring. The affordability, portability, and ease of use of these instruments have been pivotal factors for their implementation on farm. In fact, pocket-sized devices enable nonexpert users to perform quick, low-cost, and nondestructive analysis on various matrixes without complex preparation. Because bovine colostrum (BC) quality is mostly given by the IgG level, evaluating the ability of portable NIRS tools to measure antibody concentration is advisable. In this study we used the wireless device SCiO manufactured by Consumer Physics Inc. (Tel Aviv, Israel) to collect BC spectra and then attempt to predict IgG concentration and gross and fine composition in individual samples collected immediately after calving (<6 h) in primiparous and pluriparous Holstein cows on 9 Italian farms. Chemometric analyses revealed that SCiO has promising predictive performance for colostral IgG concentration, total Ig concentration, fat, and AA. The coefficient of determination of cross-validation (R2CV) was in fact ≥0.75). Excellent accuracy was observed for dry matter, protein, and S prediction in cross-validation and good prediction ability in external validation (R2CV ≥ 0.93; the coefficient of determination of external validation, R2V, was ≥0.82). Nonetheless, SCiO's ability to discriminate between good- and low-quality samples (IgG ≥ vs. < 50 g/L) was satisfactory. The affordable cost, the accurate predictions, and the user-friendly design, coupled with the increased interest in BC within the dairy sector, may boost the collection of extensive BC data for management and genetic purposes in the near future.

Creating models for the prediction of colostrum quantity, quality, and immunoglobulin G yield in multiparous Jersey cows from performance in the previous lactation and environmental changes

With multiparous Jersey cows, colostrum production seems to be variable. Due to this, we aimed to identify specific variables involved in colostrum production and quality. From 2021 to 2023, data from 28 US farms (415 multiparous Jersey cows) were used to investigate if colostrum yield, IgG concentration (g/L), and IgG yield (g) could be predicted by farm variables and transmitting abilities. With the data collected, multiple regression equations were developed to aid in predicting colostrum yield, IgG concentration, and IgG yield. Colostrum was weighed and sampled for IgG analysis. Dairy Herd Information (DHI), calving, diet, and management information data were compiled. Days below 5°C (D<), days above 23°C (D>), and days between 5 and 23°C (D) were recorded. We evaluated transmitting abilities for milk, fat, protein, and dollars; previous lactation milk yield, fat percent, fat yield, protein percent, protein yield, previous lactation somatic cell score, previous lactation days open, previous lactation days dry, previous lactation days in milk, and previous parity; and current lactation parity, days dry, and calving information, birth ordinal day, and latitude. Colostrum yield, IgG yield, and concentration had 1 added to correct for values = 0. After addition, values >0 were transformed to ln or log10. Nontransformed variables were also used to develop the model. Variance inflation factor analysis was conducted, followed by backward elimination. The log10 colostrum yield model (R2 = 0.55; β in parentheses) included herd size (-0.0001), ordinal days (-0.001), ln ordinal days (0.07), latitude (-0.02), dry period length (0.004), D< (-0.005), D (-0.003), time to harvest (0.05), ln time to harvest (-0.35), IgG (-0.004), log10 IgG (0.46), feedings per day (0.06), ln pasture access (-0.13), and ln previous lactation days open (0.14). The model showed that previous lactation days open contributed the most toward increasing and latitude contributed the most toward decreasing colostrum yield. The IgG model (R2 = 0.21) included herd size (0.02), D> (0.38), ln time to harvest (-19.42), colostrum yield (-4.29), ln diet type (18.00), ln previous lactation fat percent (74.43), and previous parity (5.72). The model showed that previous lactation milkfat percent contributed the most toward increasing and time from parturition to colostrum harvest contributed the most toward decreasing colostrum IgG concentration. The log10 IgG yield model (R2 = 0.79) included ln ordinal days (0.03), time to harvest (-0.01), colostrum yield (-0.11), ln colostrum yield (1.20), ln pasture access (-0.09), ln previous lactation fat percent (0.53), and previous parity (0.02). The model showed that colostrum yield contributed the most toward increasing IgG yield, followed by previous lactation milkfat percentage. Pasture access contributed the most toward decreasing IgG yield, although the contribution was very small. These models were validated using 39 samples from 22 farms. Actual minus predicted colostrum yield and IgG concentration and yield were 0.89 kg, -21.10 g/L, and -65.15 g, respectively. These models indicate that dry period management and cow information can predict colostrum yield and IgG concentration and yield.

Impact of Parenteral Maternal Supplementation with Trace Minerals and Vitamins on Neonatal Calf Antioxidant System and Growth in a Dairy Herd

Oxidative stress may affect new born calves due to high stress suffered around birth. We hypothesized that maternal supplementation with micronutrients and vitamins in late gestation enhance the neonatal calf's antioxidant system, decreasing the occurrence and duration of diarrhea, and improving growth from birth through weaning. To test this hypothesis, 80 multiparous cows were cluster-assigned to treatment groups. Treated group (TG) cows received mineral and vitamin supplementation while control group (CG) cows received saline solution. Feed intake and fecal score were measured daily until the ninth week. Weight and body measurements were registered weekly, and blood samples were collected from postpartum cows and calves after birth and at 7, 14, and 63 days of life. Although CG calves had greater fecal scores (p = 0.01), diarrhea characteristics did not differ. Calves in the TG showed greater starter intake (p = 0.04). Feed efficiency showed a trend with treatment-age interaction (p = 0.06). Calves in the CG had wider hips in the first week (p = 0.03), but not by the ninth week. Total antioxidant status, thiobarbituric acid reactive substances, and haptoglobin did not differ between treatment groups. Serum metabolites showed no differences. Supplementation did not impact calf antioxidant system or growth in the first two months.

Severe colic in a newborn dairy calf caused by a large colostrum curd: a case report

A newborn female, Holstein calf weighing approximately 38.5 kg developed severe, persistent colic caused by a large colostrum curd located within the calf's abomasum. Based upon 10% body weight, the calf had been fed 4 liters (L) of first-milking colostrum approximately 30 min after birth and an additional 2 L of first-milking colostrum 6 h after the first feeding. Both the first and second feedings used an esophageal tube feeder to deliver the colostrum. Colic developed shortly after the second colostrum feeding. The affected calf did not respond to on-farm supportive medical therapy and was humanely euthanized by a penetrating captive bolt approximately 22 h after the onset of colic. This on-farm colostrum feeding protocol is routinely observed in the current dairy industry. This case demonstrates calves that are fed large volumes of colostrum during a relatively short window of time may develop a large, firm colostrum curd within the abomasum that causes abdominal distension, colic, and occasional death. There is an urgent need for prospective analytical studies that determine the optimal immunoglobulin mass (g/L) and the ideal volume of colostrum fed to newborn calves for both the first and second colostrum feedings within the most beneficial time frame. Guidelines should be developed that minimize complications that adversely affect calf health and well-being while ensuring the successful transfer of passive immunity.

Colostrum Replacement and Serum IgG Concentrations in Beef Calves Delivered by Elective Cesarean Section

Assistance during calving and cesarean section (C-section) are important risk factors for the failure of transfer of passive immunity (FTPI) in beef calves, which increases the risk of morbidity and mortality in beef calves during the preweaning period. Colostrum replacement recommendations for beef calves, and especially for those delivered by C-section, are unavailable. The objective of this study was to determine whether or not colostrum replacement or supplementation with a commercially available product could increase serum IgG concentrations in beef calves delivered by elective C-section, compared to beef calves that nursed colostrum naturally. An elective C-section was performed in 32 pregnant beef cows and first-calf heifers. Immediately after delivery, newborn calves were randomly assigned to one of three different treatment groups. Group A calves (n = 7) were fed one packet of a commercial colostrum replacer (CR) product providing 60 g of IgG within 30 min of life. A second packet of the same CR was fed at 6 h of life. Group B calves (n = 13) were fed the same CR at the same frequency as group A; however, these calves were reunited with their dams after the second CR feeding to allow additional nursing of maternal colostrum. Group C calves (n = 12) were united with their dams immediately after surgery without colostrum intervention. Serum IgG levels at 48 h of life were greater in group C calves and in calves born to multiparous cows. Based on the results of this study, neither colostrum replacement nor supplementation result in higher serum IgG concentrations in beef calves delivered by elective C-section compared with natural nursing.

Dairy producers' colostrum practices, marketing, and attitudes toward male dairy calves

Optimal early-life care of surplus calves born on dairy farms is critical for health and welfare. This cross-sectional study aimed to describe the marketing practices of male dairy calves, differences in the colostrum management between male and female calves on dairy farms, and the relationship between discrepant colostrum practices and dairy producers' attitudes toward male calf care. United States dairy producers (n = 1,000) in the states of Florida, Michigan, Ohio, Vermont, and Wisconsin were selected using stratified random sampling. A questionnaire containing questions about farm demographics, colostrum management (including quantity and timeliness of colostrum delivery), and producers' attitudes toward male calf care was mailed in February 2021. Attitudes toward male calf care were assessed using 5-point Likert scales for 10 statements regarding perceptions of the value of male calves and barriers in providing optimal care. Producer responses to questions about the quantity and timeliness of colostrum delivery between male and female calves were compared using a nonparametric Wilcoxon rank-sum test. Multivariable logistic regression models were used to investigate the association between differences in colostrum management and producers' attitudes. By May 2021, 953 surveys were delivered and 315 (33.1%) were returned with complete responses. Most producers (>90%) reported feeding equal volumes of colostrum and performing the first postbirth feeding within a similar time frame for male and female calves. However, compared with females, male calves had a longer delay to the first colostrum feeding. Approximately 40% of producers marketed their male calves through auctions, and over half (54.6%) of farms sold the male calves between 3 and 10 d of age. Large farms (≥500 lactating cows) were found to market male calves at a younger age (≤3 d of age). Most producers (>78%) believed their male calves were receiving optimal care and did not consider the workload and financial costs as obstacles to providing good care to male calves. However, those who viewed the workload as an obstacle to good care and produced organic products were marginally more likely to feed a lower volume of colostrum to male calves in the first feeding after birth. These findings suggest that interventions to improve colostrum practices should be more broadly targeted to all calves born on dairy farms, and that age at transport is markedly different between large and small farms.

Forage sources in total mixed rations early in life influence performance, metabolites, and behavior of dairy calves

The objective of this study was to evaluate effects of forage inclusion and sources on performance, metabolism, and feeding behavior of dairy calves. Forty-eight Holstein calves were blocked and randomly assigned to 1 of 4 dietary treatments according to sex and BW at 28 d of life to determine the effects of feeding forage sources (ensiled and dry), with different quality on performance, metabolites, and behavior. Treatments consisted of a no-forage coarsely ground starter (CON); or total mixed ration (TMR) containing 7.5% on a dry matter (DM) basis of Tifton hay of either medium quality (MH) or low quality (LH); or 10% on a DM basis of corn silage (CS). During the first 28 d of life, all calves received 3 L of whole milk twice daily, a commercial pelleted starter and no forage, and water ad libitum. After that, the solid diet was changed to the respective dietary treatments. Calves were gradually weaned from 52 to 56 d of age, and followed for 14 d postweaning. Individual solid feed and milk intakes were recorded daily, and BW and metabolic indicators of intermediate metabolism were recorded weekly. Behavior was recorded, and the analysis was conducted on wk 7 (preweaning) and 10 (postweaning). Solid feed intake increased at wk 7 and 8 when MH, LH, and CS were included in TMR; the same results were observed postweaning. The diets did not affect the average daily gain and BW, but the feed efficiency increased with the CON diet. The β-hydroxybutyrate concentration was greater in calves receiving TMR-containing forage than CON diet. Furthermore, calves supplemented with forage had a greater rumination time. In conclusion, all forage sources included in the TMR showed feed intake and behavior benefits, reinforcing the need for fiber from forage in pre- and postweaning diets.

Effects of weaning age and pace on blood metabolites, cortisol concentration, and mRNA abundance of inflammation-related genes in gastrointestinal, adipose, and liver tissue of Holstein dairy calves

The objective of this study was to evaluate the effects of weaning age and pace on blood metabolites, cortisol concentration, and mRNA abundance of inflammation-related genes in Holstein dairy calves. A total of 70 1-d-old calves (38.8 ± 4.4 kg BW ± SD), blocked by sex and birth BW, were randomly assigned to a 2 × 2 factorial arrangement of treatments. The first factor was weaning age, which was either early (6 wk) or late (8 wk). The second factor was weaning pace, which was either abrupt (4 steps down over 3 d; the initial milk replacer was 7.6 L, which was reduced by 1.9 L in each step-down) or gradual (7 steps down over 14 d; the initial milk replacer was 7.6 L, which was reduced by 1.09 L in each step-down), generating early-abrupt (EA), early-gradual (EG), late-abrupt (LA), and late-gradual (LG) treatments. All treatments had 10 female and 8 male calves, except EA that had 1 fewer male calf. Milk replacer (24% CP, 17% fat) was bottle fed, up to 1,200 g/d, twice daily (0600 h and 1800 h). The EA and EG treatment calves received 46.2 kg of milk replacer, and the LA and LG treatment calves received 63 kg of milk replacer. The study had 2 cohorts (2020, n = 40; 2021, n = 31), and each cohort included all treatments. Blood was collected from the jugular vein at 0900 h at 3 and 7 d of age, and a day before starting and a day after weaning completion. Male calves were humanely killed a day after weaning. Rumen, jejunum, large intestine, liver, omental adipose and perirenal adipose tissues were sampled to determine the mRNA abundance of inflammation-related genes. Weaning pace, age, pace × age, birth BW, and sex were included as fixed and cohort was included as random effects in the model. Blood metabolites and cortisol were analyzed as repeated measures, and sampling day, pace × sampling day, and age × sampling day were also included as additional fixed effects. Significance was noted at P ≤ 0.05 and tendencies when 0.05

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Key Words

• inflammation
• inflammatory markers
• preruminant calves
• weaning strategies

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MESH Headings

• Animals
• Cattle
• Weaning
• Hydrocortisone/blood
• Inflammation/veterinary
• Female
• Diet/veterinary
• Liver/metabolism
• RNA, Messenger/metabolism
• Male
• Adipose Tissue/metabolism

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Affiliation(s)

B C Agustinho Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, ID 83844
A Wolfe Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5
C Y Tsai Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, ID 83844
L M Pereira Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, ID 83844
D E Konetchy Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, ID 83844
A H Laarman Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, ID 83844; Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada T6G 2P5
P Rezamand Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, ID 83844.

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Association of morbidity, mortality, and average daily gain with transfer of passive immunity in dairy-beef crossbred calves up to 60 d of life

Adequate transfer of passive immunity (TPI) is a cornerstone for a proper health status of calves. In the literature, there is limited information on the prevalence of failure of TPI in dairy-beef crossbred calves and its impact on morbidity, mortality, and average daily gain (ADG) during the preweaning period. Therefore, this study aimed to evaluate the association between TPI with morbidity, mortality, and ADG in pre-weaned dairy-beef crossbred calves. A total of 1,055 newborn dairy-beef crossbred calves were enrolled upon arrival at a calf-raising facility in California from January to August 2021. Farm of origin, genetic breed group, sex, and body weight were recorded upon arrival. Blood was collected at 24 ± 1 h post-arrival to evaluate serum IgG concentration, serum total protein (TP), and packed cell volume. Morbidity (diarrhea and respiratory treatment records) and mortality were recorded daily until 60 d of life. Calves were grouped into 2 genetic breed groups: Holstein x Beef (Ho x Be, 49.6%) and Jersey × Beef crossbred calves (Je × Be, 50.4%). Descriptive statistics and Cox proportional hazard models were created to evaluate the association of TPI categories for serum IgG (TPI-IgG: poor: < 10.0 g/L, fair: 10.0 - 17.9 g/L, good: 18.0 - 24.9 g/L, and excellent: ≥ 25.0 g/L) and TP (TPI-TP: poor: < 5.1 g/dL, fair: 5.1 - 5.7 g/dL, good: 5.8 - 6.1 g/dL, and excellent: ≥ 6.2 g/dL), sex, and genetic breed group with morbidity and mortality. Additionally, a mixed linear regression was performed to evaluate the association of sex, genetic breed group, and TPI categories with ADG. Overall morbidity and mortality were 84.8% (n = 895) and 2.5% (n = 26). Calves classified as TPI-IgG excellent were associated with the lowest (43.2% less) hazard of being treated compared with TPI-IgG poor calves. For mortality, dairy-beef crossbred calves with TPI-IgG excellent were associated with a reduction of 82.0% in the hazard of dying compared with TPI-IgG poor. The TPI-IgG poor and TPI-IgG fair calves were associated with a decreased ADG of 101.0 and 98.8 g/d, respectively, in comparison with TPI-IgG good calves. Average daily gain of TPI-IgG good and TPI-IgG excellent calves were not different. In our study, dairy-beef crossbred calves enrolled may have endured challenging conditions that increased morbidity. This reinforces the importance of high IgG levels to decrease morbidity and mortality and maximize ADG in dairy-beef crossbred calves raising systems. Further research should evaluate the long-term effects of TPI categories on the health and performance of dairy-beef crossbred calves.

INVITED REVIEW: An evaluation of EFSA opinion on calf welfare from a nutritional and management perspective

In March, 2023, the European Food Safety Authority published a Scientific Opinion on Calf Welfare. This Opinion was prepared in response to a request from the European Commission to provide an independent view on the welfare of calves that reflected the most recent scientific knowledge. Data sources used to develop their recommendations included peer-reviewed studies, expert knowledge, and gray literature. The Opinion considered specific scenarios and welfare consequences of specific management practices, including feeding fiber to calves raised for white veal and amount of cow-calf contact. Their Opinion suggested that calves should be fed specific quantities of forage NDF during the rearing cycle. Regarding separation of calves, the Committee recommended that the calf should remain with the cow for a minimum of 24 h and then be housed with another calf. They further suggested that prolonged cow-calf contact should increasingly be implemented due to benefits to both cow and calf to minimize stress of separation. The objective of this review is to assess the veracity of these recommendations and the scientific data that underpins them. This review will present a literature to support the contention that, from a nutritional and management perspective, these recommendations may impair calf welfare by exposing calves to innutritious rations containing excess fiber and increasing their risk of morbidity and mortality due to poor colostrum intake and exposure to disease-causing pathogens. Alternative recommendations are made that may further the goal of calf welfare in the context of nutrition and housing.

Salivary IgG and IgA in newborn calves and the possible role in the assessment of passive immunity transfer

Introduction

The transfer of immunoglobulins from the mother to newborns is widely recognized as a critical event for safeguarding offspring against potentially life-threatening infectious diseases. Mainly for this reason, this study aimed to assess the concentrations of immunoglobulin G (IgG) and immunoglobulin A (IgA) in the saliva of newborn calves and explore its potential use for monitoring passive immunity transfer from cows to calves, as also to evaluate how colostrum intake affects serum and saliva IgG and IgA concentrations.

Methods

The quality of colostrum samples was evaluated using an optical refractometer before administration to the calves. Saliva and blood samples from 24 calves were obtained at the day of birth (T0) and 2 days after (T2) for determination of serum concentrations of total protein by refractometer, IgG and IgA (both on serum and saliva) by ELISA test.

Results

Positive correlations were observed between salivary IgA at T2 and salivary IgG at T2. A significant increase in both IgG and IgA levels in calf serum and saliva was noted. Salivary IgA levels can reflect salivary IgG levels.

Discussion

These findings suggest the potential utility of IgA in monitoring passive immunity transfer, and do not exclude saliva as an alternative, practical, and non-invasive matrix for assessing passive immunity transfer.

Persistence of passive immunity in calves receiving colostrum from cows vaccinated with a live attenuated lumpy skin disease vaccine and the performance of serological tests

This study aimed to determine the persistent duration of maternal immunity against lumpy skin disease virus (LSDV) in dairy calves born from vaccinated cows using a virus neutralization test (VNT). The performance of the VNT and an in-house-ELISA test was also determined. Thirty-seven pregnant cows from 12 LSD-free dairy farms in Lamphun province, Thailand were immunized with a homologous Neethling strain-based attenuated vaccine and calved from December 2021 to April 2022. Blood samples from dam-calve pairs were collected within the first week after calving. Subsequently, blood samples were taken from the calves at monthly intervals over a period of 4 months and tested for the humoral immune response using a VNT. The calf sera were also tested with an in-house ELISA test to estimate the accuracy of both tests using a Bayesian approach. For the results, antibodies against LSDV can persist in cows for 4-9 months post-vaccination. Moreover, neutralizing antibodies and LSDV-specific antibodies against LSDV were detected in the majority of calves (75.68%) during the first week after colostrum intake. However, the percentage of seropositive calves declined to zero by day 120, with seropositivity dropping below 50% after day 60. Only a small number of seropositive calves (approximately 13.51%) were observed on day 90. These findings indicated that passive immunity against LSDV can last up to 3 months. The median of posterior estimates for sensitivity (Se) and specificity (Sp) of the VNT were 87.3% [95% posterior probability interval (PPI) = 81.1-92.2%] and 94.5% (95% PPI = 87.7-98.3%), respectively. The estimated Se and Sp for the ELISA test were 83.1% (95% PPI = 73.6-92.6%) and 94.7% (95% PPI = 88.4-98.5%), respectively. In conclusion, this study illustrates the transfer and persistence of maternal passive immunity against LSDV to calves under field conditions. This highlights a potential three-month vaccination gap in calves born from vaccinated cows, while an in-house ELISA test can be used as an ancillary test for LSDV immune response detection. However, further research is required to assess the vaccination protocols for calves as young as 2 months old to precisely determine the duration of maternal immunity.

Dairy calf transportation in the United States: Challenges and strategies to improve animal welfare

The objectives of this symposium review are to summarize relevant research and key welfare issues relative to calf transportation and identify strategies to mitigate welfare challenges. An important animal welfare concern across the US dairy industry is the transportation of preweaning calves from the source dairy to a calf-raising facility (e.g., calf ranches, heifer raising facilities, veal operations), auction, livestock market, or directly to slaughter. Millions of calves are transported annually in the United States and calf transport has garnered increased attention. Transportation stressors include limited (if any) access to food and water, commingling, environmental temperature changes, and a variety of handling techniques. Calves in the United States are often transported at an average age of 3 d, and in many cases, less than 24 h of age. Neonates are particularly vulnerable to transportation stressors due to their decreased ability to thermoregulate, underdeveloped immune system, and immature physiologic stress responses. In addition to age, fitness for transport is a key welfare consideration; recent data from the United States demonstrate that some source dairies transport compromised calves (i.e., dehydration, diarrhea, navel inflammation, and so on), leading to important welfare challenges during transportation. Calves arriving at US veal facilities have been reported to be dehydrated, lethargic, hypoglycemic, and may also have poor body condition, navel inflammation, and diarrhea. Thus, there is ample opportunity to target decision-making and producer-focused education not only at the source dairy, but also at each stage of transportation to address critical welfare concerns. In addition, the supply chain and procurement model that influence calf transport practices should be evaluated to determine potential opportunities to improve calf welfare. Here, we provide 5 potential strategies to improve the welfare of transported calves: (1) provide excellent newborn care that "preconditions" calves for transport, (2) assess calves' fitness-for-transport to ensure they can withstand the journey, (3) handle calves with care, (4) wait until calves are older to transport, and (5) reduce transport duration.

Association of passive immunity and genetic composition, health, and performance of tropical dairy calves

This retrospective cohort study aimed to identify risk factors for the failure of transfer of passive immunity (FPI) in preweaned dairy calves, explore its associations with morbidity, mortality, genetics, and determine a standardized cut-off point for FPI. Analyzing data from 6011 calves, factors such as sire predicted transmitted ability for milk (PTA), birth season, retained placenta (RP), total serum protein concentration (TSP), morbidity (neonatal calf diarrhea - NCD, bovine respiratory disease - BRD, tick-borne disease - TBD), mortality, and average daily weight gain (ADG) were considered. The calves were categorized into predominantly Gyr (PG) and predominantly Holstein (PH) genetic composition groups. Multivariate mixed logistic regression revealed optimal TSP cut-off points for predicting morbidity (7.6 g/dL) and mortality (6.9 g/dL). PH calves exhibited 1.35 times higher odds of FPI and 1.48 times greater odds of disease. Calves from multiparous cows and those born to dams with RP had increased FPI odds. Disease prevalence was 53%, with 41% NCD, 18% BRD, and 10% TBD. Season, parity, PTA, and birth weight were associated with disease odds, though FPI was not a reliable predictor. The mortality percentage was 6%, with PH calves and those with a positive PTA having higher odds. The ADG was 0.64 kg, and FPI-affected calves gained less weight. The study compared and identified various risk factors that potentially impact calf immunity. However, the use of a standardized cut-off point for FPI assessment was not effective in predicting morbidity and mortality at this specific farm.

Bovine milk microbiota: Key players, origins, and potential contributions to early-life gut development

BACKGROUND

Bovine milk is a significant substitute for human breast milk and holds great importance in infant nutrition and health. Apart from essential nutrients, bovine milk also contains bioactive compounds, including a microbiota derived from milk itself rather than external sources of contamination.

AIM OF REVIEW

Recognizing the profound impact of bovine milk microorganisms on future generations, our review focuses on exploring their composition, origins, functions, and applications.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Some of the primary microorganisms found in bovine milk are also present in human milk. These microorganisms are likely transferred to the mammary gland through two pathways: the entero-mammary pathway and the rumen-mammary pathway. We also elucidated potential mechanisms by which milk microbiota contribute to infant intestinal development. The mechanisms include the enhancing of the intestinal microecological niche, promoting the maturation of immune system, strengthening the intestinal epithelial barrier function, and interacting with milk components (e.g., oligosaccharides) via cross-feeding effect. However, given the limited understanding of bovine milk microbiota, further studies are necessary to validate hypotheses regarding their origins and to explore their functions and potential applications in early intestinal development.

Colostrum as a source of ESBL-Escherichia coli in feces of newborn calves

The aim of the present study was to determine if colostrum and the equipment for harvesting and feeding colostrum are sources of fecal ESBL/AmpC-producing Escherichia coli (ESBL/AmpC-E. coli) in calves. Therefore, 15 male calves fed with pooled colostrum on a dairy farm and held individually in an experimental barn, the colostrum pool and the equipment for harvesting and feeding colostrum were sampled and analyzed for the occurrence of ESBL/AmpC-E. coli. The ESBL-AmpC-E. coli suspicious isolates were subjected to whole-genome sequence analysis. Forty-three of 45 fecal samples were tested positive for ESBL/AmpC-E. coli. In the colostrum sample and in the milking pot, we also found ESBL/AmpC-E. coli. All 45 E. coli isolates were ESBL-producers, mainly commensal sequence type (ST) 10, but also human-extraintestinal pathogenic E. coli ST131 and ST117 were found. The clonal identity of six fecal isolates with the ESBL-E. coli isolate from the colostrum and of five fecal isolates with the strain from the milking pot demonstrates that the hygiene of colostrum or the colostrum equipment can play a significant role in the spread of ESBL-E. coli. Effective sanitation procedures for colostrum harvesting and feeding equipment are crucial to reduce the ESBL-E. coli shedding of neonatal dairy calves.

Health-associated changes of the fecal microbiota in dairy heifer calves during the pre-weaning period

Introduction

Neonatal calf diarrhea is a multifactorial condition that occurs in early life when calves are particularly susceptible to enteric infection and dysbiosis of the gut microbiome. Good calf health is dependent on successful passive transfer of immunity from the dam through colostrum. There are limited studies on the developing gut microbiota from birth to weaning in calves.

Methodology

Therefore, the objective of this study was to examine the effect of immune status and diarrheal incidence on the development of the fecal microbiota in Jersey (n = 22) and Holstein (n = 29) heifer calves throughout the pre-weaning period. Calves were hand-fed a colostrum volume equivalent to 8.5% of their birthweight, from either the calf's dam (n = 28) or re-heated mixed colostrum (≤2 cows, ≤1d; n = 23) within 2 h of birth. All calves were clinically assessed using a modified Wisconsin-Madison calf health scoring system and rectal temperature at day (d) 0, d7, d21, or disease manifestation (DM) and weaning (d83). Weights were recorded at d0, d21, and d83. Calf blood samples were collected at d7 for the determination of calf serum IgG (sIgG). Fecal samples were obtained at d7, d21/DM [mean d22 (SE 0.70)], and at weaning for 16S rRNA amplicon sequencing of the fecal microbiota. Data were processed in R using DADA2; taxonomy was assigned using the SILVA database and further analyzed using Phyloseq and MaAsLin 2.

Results and discussion

Significant amplicon sequence variants (ASVs) and calf performance data underwent a Spearman rank-order correlation test. There was no effect (p > 0.05) of colostrum source or calf breed on serum total protein. An effect of calf breed (p < 0.05) was observed on sIgG concentrations such that Holstein calves had 6.49 (SE 2.99) mg/ml higher sIgG than Jersey calves. Colostrum source and calf breed had no effect (p > 0.05) on health status or the alpha diversity of the fecal microbiota. There was a relationship between health status and time interaction (p < 0.001), whereby alpha diversity increased with time; however, diarrheic calves had reduced microbial diversity at DM. No difference (p > 0.05) in beta diversity of the microbiota was detected at d7 or d83. At the genus level, 33 ASVs were associated (adj.p < 0.05) with health status over the pre-weaning period.

A Comprehensive Review of Bovine Colostrum Components and Selected Aspects Regarding Their Impact on Neonatal Calf Physiology

Colostrum contains macro- and micronutrients necessary to meet the nutritional and energy requirements of the neonatal calf, bioactive components that intervene in several physiological aspects, and cells and microorganisms that modulate the calf's immune system and gut microbiome. Colostrum is sometimes mistaken as transition milk, which, although more nutritive than whole milk, has a distinct biochemical composition. Furthermore, most research about colostrum quality and colostrum management focuses on the transfer of maternal IgG to the newborn calf. The remaining components of colostrum and transition milk have not received the same attention, despite their importance to the newborn animal. In this narrative review, a large body of literature on the components of bovine colostrum was reviewed. The variability of these components was summarized, emphasizing specific components that warrant deeper exploration. In addition, the effects of each component present in colostrum and transition milk on several key physiological aspects of the newborn calf are discussed.

Graduate Student Literature Review: Developmental adaptations of immune function in calves and the influence of the intestinal microbiota in health and disease

This graduate student literature review provides an examination of the ontological adaptations of the calf's immune system and how the intestinal microbiota influences calf immune function in health and disease. Within dairy rearing systems, various nutritional and management factors have emerged as critical determinants of development influencing multiple physiological axes in the calf. Furthermore, we discuss how multiple pre- and postnatal maternal factors influence the trajectory of immune development in favor of establishing regulatory networks to successfully cope with the new environment, while providing early immune protection via immune passive transfer from colostrum. Additionally, our review provides insights into the current understanding of how the intestinal microbiota contributes to the development of the intestinal and systemic immune system in calves. Lastly, we address potential concerns related to the use of prophylactic antimicrobials and waste milk, specifically examining their adverse effects on intestinal health and metabolic function. By examining these factors, we aim to better understand the intricate relationship between current management practices and their long-term effect on animal health.

Developmental programming of reproduction in the female animal

Successful reproduction is a cornerstone in food animal industry in order to sustain food production for human. Therefore, various methods focusing on genetics and postnatal environment have been identified and applied to improve fertility in livestock. Yet there is evidence indicating that environmental factors during prenatal and/or neonatal life can also impact the function of reproductive system and fertility in the animals during adulthood, which is called the developmental programming of reproduction. The current review summarizes data associated with the developmental origins of reproduction in the female animals. In this regard, this review focuses on the effect of plane of nutrition, maternal body condition, hypoxia, litter size, maternal age, parity, level of milk production and milk components, lactocrine signaling, stress, thermal stress, exposure to androgens, endocrine disrupting chemicals, mycotoxins and pollutants, affliction with infection and inflammation, and maternal gut microbiota during prenatal and neonatal periods on the neuroendocrine system, puberty, health of reproductive organs and fertility in the female offspring. It is noteworthy that these prenatal and neonatal factors do not always exert their effects on the reproductive performance of the female by compromising the development of organs directly related to reproductive function such as hypothalamus, pituitary, ovary, oviduct and uterus. Since they can impair the development of non-reproductive organs and systems modulating reproductive function as well (e.g., metabolic system and level of milk yield in dairy animals). Furthermore, when these factors affect the epigenetics of the offspring, their adverse effects will not be limited to one generation and can transfer transgenerationally. Hence, pinpointing the factors influencing developmental programming of reproduction and considering them in management of livestock operations could be a potential strategy to help improve fertility in food animals.

Condition of surplus dairy calves during marketing: A cross-sectional study

In North America, surplus dairy calves are sold soon after birth and often marketed through a third party (e.g., live auction, livestock dealer) before entering veal or dairy beef production. Previous work has demonstrated that a percentage of calves have failed transfer of passive immunity (FTPI) and clinical signs of disease on arrival at calf-raising facilities, but little is known regarding calf condition during marketing. The objectives of this cross-sectional study were to (1) estimate the prevalence of FTPI and poor health outcomes in surplus calves on arrival at livestock dealers, and (2) investigate the association between calf-level variables (body weight, sex, source) and health outcomes. Two livestock dealers in Ohio were visited 2 to 3 times per week, with approximately 28 calves enrolled in the study per visit for a total of 1,119 calves. One blood sample per calf was obtained to evaluate FTPI by measuring serum total protein concentrations (using a cutoff <5.1 g/dL). Calves were clinically evaluated for signs of arthritis, broken ribs or tail, dehydration, depression, diarrhea, fever, navel inflammation, and respiratory disease by 2 observers; health outcomes were dichotomized using clinically relevant cut points. Descriptive statistics were used to estimate the prevalence of calves with poor health outcomes. Multivariable logistic regression models were built to investigate the effect of body weight, sex, and source on health outcomes. Nineteen percent (206/1,091) of calves had FTPI.

Microbiological risk assessment and resistome analysis from shotgun metagenomics of bovine colostrum microbiome

Colostrum is known for its nutraceutical qualities, probiotic attributes, and health benefits. The aim of this study was to profile colostrum microbiome from bovine in rural sites of a developing country. The focus was on microbiological safety assessments and antimicrobial resistance, taking into account the risks linked with the consumption of raw colostrum. Shotgun sequencing was employed to analyze microbiome in raw buffalo and cow colostrum. Alpha and beta diversity analyses revealed increased inter and intra-variability within colostrum samples' microbiome from both livestock species. The colostrum microbiome was mainly comprised of bacteria, with over 90% abundance, whereas fungi and viruses were found in minor abundance. Known probiotic species, such as Leuconostoc mesenteroides, Lactococcus lactis, Streptococcus thermophilus, and Lactobacillus paracasei, were found in the colostrum samples. A relatively higher number of pathogenic and opportunistic pathogenic bacteria were identified in colostrum from both animals, including clinically significant bacteria like Clostridium botulinum, Pseudomonas aeruginosa, Escherichia coli, and Listeria monocytogenes. Binning retrieved 11 high-quality metagenome-assembled genomes (MAGs), with three MAGs potentially representing novel species from the genera Psychrobacter and Pantoea. Notably, 175 antimicrobial resistance genes (ARGs) and variants were detected, with 55 of them common to both buffalo and cow colostrum metagenomes. These ARGs confer resistance against aminoglycoside, fluoroquinolone, tetracycline, sulfonamide, and peptide antibiotics. In conclusion, this study describes a thorough overview of microbial communities in buffalo and cow colostrum samples. It emphasizes the importance of hygienic processing and pasteurization in minimizing the potential transmission of harmful microorganisms linked to the consumption of colostrum.