Calf Health Research Articles

Does micro-granulated yeast probiotic (Saccharomyces cerevisiae) supplementation in milk replacer affect health, growth, feed efficiency and economic gain of calves?

The goal of calf feeding systems is to provide calves with optimum nutrition to promote growth, health, and future milk production and to reduce antibiotic use which leads to a need for alternatives that reduce illness and promote growth in dairy calves. We hypothesized that feeding live yeast would improve gastrointestinal health and growth performance of calves. The aim of this study was then to evaluate the effects of supplementing a yeast probiotic Saccharomyces cerevisiae (CNCM I-4407, 1010 CFU/g, Actisaf® Sc47 powder; Phileo by Lesaffre, France) in milk replacers (MR), on health and growth of pre-weaned calves. Forty Holstein female calves were used during this trial. Each calf was weighed at 3 days of age and then introduced in the trial. Calves were randomly assigned to 2 groups (n = 20/group) and were fed MR without (control; CON) or with yeast probiotic at 1 g/calf/d (experimental; EXP). Milk replacer (12.5 % solids) was offered twice a day until 66 days of age (DOA). Body Weight (BW), wither height, hip width, body length and chest girth were collected in day 3 and day 66. Compared to CON, calves supplemented with yeast probiotic had better average daily gain (ADG, 0.456 ± 0.1 vs. 0.556 ± 0.09 kg/d, p < 0.05). There was no difference (p > 0.05) in both starter and MR intake between the two groups. Feed efficiency was better (p < 0.05) in the EXP group (2.18 ± 0.53) compared to CON (2.63 ± 0.78). No statistical differences were found between groups even if the lower total morbidity (40.91 % in the CON vs. 19.05 % in EXP) and incidence of gastrointestinal disorders (36.36 % in the CON vs. 14.29 % in EXP) were observed in calves supplemented with yeast probiotic. The severity of diarrhea was numerically lower in calves supplemented with yeast probiotic. No severe cases of respiratory disorders were highlighted in the present trial. The cost/kg of gain was higher (p < 0.05) in CON compared to EXP group. Total expenses linked to feeds and veterinary treatments were higher in CON compared to EXP group. During the study, the use 1 g/d of yeast probiotic allows to save 32.86 €/calf.It could be concluded that supplementing Actisaf® powder (Actisaf® SC 47 PWD) in MR improved health, growth performance, feed efficiency, and reduced the expenses linked to feeds and veterinary treatments.

Understanding Calf Behavioral Responses to Environmental Changes and Challenges: An Applied Update

In most of the artificial raising operations, the separation of dairy calves from their dams immediately after birth and reared under a variety of housing and feeding systems, expose them to different environmental challenges. The objective of this review article was to describe how environmental changes and challenges influence the health and behavior of young calves. Natural behavior, health, and welfare of the calves may be affected when they are reared indoors apart from their dams with another mate. Fresh perspectives on calf nourishment strategies (e.g., intensified vs. conventional milk feeding, and forage feeding) and housing (group or pair vs. individual) have been developed to assimilate the natural environment of calves. In recent years, based on scientific evidence a positive relationship between early-life calf health and later performance of dairy heifers has been indicated. Chronic exposure to stressors may lead to chronic inflammation, resulting in increased infectious disease and suppressed animal performance. Therefore, an effective diagnostic tool for the identification and prediction of the health status and welfare of calves would be to monitor the behavior of calves regularly on the farm. The main factors affecting the behavior of calves and their subsequent productivity are, nutrition and feeding programs, ambient temperatures, incidences of diseases as well as housing systems. Genetics can affect calf response to environmental alterations. In general, it alleviates stress and improves herd profitability and sustainability for producers and farmers by understanding the calves' behavior in response to environmental challenges.

Subcutaneous lysophosphatidylcholine administration promotes a febrile and immune response in Holstein heifer calves

Lysophosphatidylcholine (LPC) is immunomodulatory in nonruminants; however, the actions of LPC on immunity in cattle are undefined. Our objective was to study the effects of LPC administration on measures of immunity, liver health, and growth in calves. Healthy Holstein heifer calves (n = 46; age 7 ± 3 d) were randomly assigned to 1 of 4 treatments (n = 10 to 11 calves/treatment): a milk replacer diet unsupplemented with lecithin in the absence (CON) or presence of subcutaneously (s.c.) administered mixed (mLPC; 69% LPC-16:0, 25% LPC-18:0, 6% other) or pure LPC (pLPC; 99% LPC-18:0), or a milk replacer diet supplemented with 3% lecithin enriched in lysophospholipids containing LPC in the absence of s.c.-administered LPC (LYSO) for 5 wk. Calves received 5 s.c. injections of vehicle (10 mL of phosphate-buffered saline containing 20 mg of bovine serum albumin/mL; CON and LYSO) or vehicle containing mLPC or pLPC to provide 10 mg of total LPC per kilogram of BW per injection every 12 h during wk 2 of life. Calves were fed a milk replacer containing 27% crude protein and 24% fat at 1.75% of BW per day (dry matter basis) until wk 6 of life (start of weaning). Starter grain and water were provided ad libitum. Body measurements were recorded weekly, and clinical observations were recorded daily. Blood samples were collected weekly before morning feeding and at 0, 5, and 10 h, relative to the final s.c. injection of vehicle or LPC. Data were analyzed using a mixed model, with repeated measures including fixed effects of treatment, time, and their interaction. Dunnett's test was used to compare treatments to CON. Peak rectal temperatures were higher in mLPC or pLPC, relative to CON. Plasma LPC concentrations were greater in mLPC and LYSO calves 5 h and 10 h after the final injection, relative to CON. Calves receiving mLPC and pLPC also had higher circulating serum amyloid A concentrations, relative to CON. Calves receiving mLPC had greater serum aspartate aminotransferase, γ-glutamyltransferase, and glutamate dehydrogenase concentrations, relative to CON. Calves provided mLPC experienced lower average daily gain (ADG) after weaning, relative to CON. The LYSO treatment did not modify rectal temperatures, ADG, or measures of liver health, relative to CON. We conclude that LPC administered as s.c. injections induced an acute febrile response, modified measures of liver and immune function, and impaired growth in calves.

Effects of nondigestible oligosaccharides on inflammation, lung health, and performance of calves

Our objective was to determine the effects of nondigestible oligosaccharides (NDO) on lung health and performance. Three hundred male Holstein-Friesian calves aged 18.0 ± 3.6 d received 1 of 6 treatments for 8.5 wk (period 1). Treatments included a negative control (CON), galacto-oligosaccharides (GOS) administered as a spray via the nose once daily (SPR), GOS administered via the milk replacer (MR) at 1% (GOS-L) and 2% (GOS-H), fructo-oligosaccharides administered via the MR at 0.25% (FOS) and a combination of GOS and fructo-oligosaccharides administered via the MR at 1% and 0.25%, respectively (GOS-FOS). Milk replacer was fed twice daily. Feeding levels were equal between calves and increased progressively in time. Body weight was measured every 4 wk and clinical health was scored weekly. Blood and broncho-alveolar lavage fluid (BALF) samples were collected bi-weekly from a subset of calves (n = 120). After period 1, all calves received the same control MR for 18 wk until slaughter (period 2), during which general performance and clinical health were measured. Generally, infection pressure was high, with clinical scores and BALF proinflammatory TNFα concentrations increasing with time in period 1, which resulted in a high number of required group antimicrobial treatments (6 group antimicrobial treatments in 13 wk, supplied to all calves). Average daily gain adjusted to equal solid feed intake was increased for GOS-L (+61 g/d) compared with CON calves from experimental wk 1 to 5. Plasma white blood cell concentration tended to be lowered by GOS-L, plasma IL-8 concentration was reduced by all orally supplemented NDO, plasma IL-6 was reduced by all NDO treatments except GOS-FOS and plasma IL-1β was reduced by all NDO treatments compared with CON, although this differed per time point for SPR. The neutrophil percentage in BALF was reduced by GOS-L in wk 6, which was associated with a relative increase in macrophages. The BALF concentration of TNFα and IL-8 was reduced or tended to be reduced by GOS-L and GOS-H, while IL-6 was or tended to be reduced by SPR, GOS-L, GOS-H, and GOS-FOS, and IL-1β was reduced by SPR, GOS-L, GOS-H, and FOS. Generally, feeding the combination of GOS and FOS was not more effective than feeding GOS or FOS alone, because feeding GOS-FOS resulted in higher concentrations of plasma and BALF cytokine and chemokine concentrations compared with feeding GOS-L alone, and resulted in higher plasma cytokine concentrations compared with feeding FOS alone. None of the BALF and plasma cytokine or chemokine concentrations differed between the GOS-L and GOS-H treatment. Performance and clinical scores in period 2 did not differ among treatments. Altogether, all tested NDO reduced systemic and lung inflammation in calves under high natural infection pressure and for GOS-fed calves, this increased performance during the first 4 wk. Combining GOS and FOS did not have a synergistic effect. The intranasal administration of GOS also lowered systemic and lung inflammation, but tended to negatively affect performance. Overall, this study demonstrates the potential of NDO to alleviate systemic and respiratory inflammation in calves.

Eukaryotic Infections in Dairy Calves: Impacts, Diagnosis, and Strategies for Prevention and Control.

Eukaryotic infections are common among dairy calves and can have significant impacts on their health and growth rates. Fungal infections caused by Aspergillus fumigatus, Trichophyton verrucosum, and Candida albicans can cause respiratory diseases, dermatophytosis, and diarrhea, respectively. Protozoan parasites, including Cryptosporidium parvum, Giardia duodenalis, and Eimeria spp., are also common in dairy calves. C. parvum is highly contagious and can cause severe diarrhea and dehydration, while Giardia duodenalis can lead to poor growth and is transmissible to humans through contaminated food or water. Eimeria spp. can cause coccidiosis and lead to reduced growth rates, poor feed conversion, and death. The common helminthic infections in dairy calves include Ostertagia ostertagi, Cooperia spp., Fasciola hepatica, and Strongyloides papillosus. These parasitic infections significantly impact calf health, growth, and dairy industry productivity. Diagnosis of these infections can be made through fecal samples using microscopy or molecular methods. However, diagnosis of the infections can be challenging and requires a combination of clinical signs and laboratory tests such as culture and PCR. Preventing and controlling eukaryotic infections in dairy calves requires several measures. Good hygiene and sanitation practices, proper management strategies, and timely treatment of affected animals are important. It is also necessary to avoid overcrowding and consider vaccination against ringworm. Further research is needed to better understand the epidemiology and characterization of eukaryotic infections in dairy calves, which will help in the development of more effective prevention and control strategies. In general, good hygiene practices, appropriate management strategies, and timely treatment of affected animals are crucial in preventing and controlling the infections, ensuring the health and well-being of dairy calves.

Effects of Maternal Supplementation with Organic Trace Minerals including Zinc, Manganese, Copper, and Cobalt during the Late and Post-Partum Periods on the Health and Immune Status of Japanese Black Calves

In this study, we evaluated the effects of supplementation of the maternal diet with organic trace minerals including Zn (zinc), Mn (manganese), Cu (copper), and Co (cobalt) on the health and immune status of beef calves. We examined 19 pregnant cows, which were divided into a group of 9 cows fed a basal diet (control) and 10 cows fed a diet with organic trace minerals (treated). Cows were fed for a period of 45 days before the predicted calving date until 45 days after calving. The number of treatments needed for respiratory and digestive diseases within 14 days of birth was significantly lower in the treated group (p &lt; 0.05) than the control group. In addition, the concentration of serum zinc in the treated group on day 1 was significantly higher (p &lt; 0.05) than that in the control group. The numbers of CD4+ and CD8+ cells in the treated group on days 30 and 60 were significantly increased (p &lt; 0.01) compared with those in the control group, as was the number of γδ T cells on days 1 and 30 (p &lt; 0.05). The number of IgM+ cells in the treated group on days 30 and 60 was significantly increased (p &lt; 0.01) compared with that in the control group, as was the number of MHC class II+ cells on day 60 (p &lt; 0.01). The number of NK cells in the treated group on day 60 was also significantly increased (p &lt; 0.05) compared with that in the control group. The expression levels of mRNAs encoding interlukin-2 (IL-2), interlukin-4 (IL-4), interlukin-12 (IL-12), and interferon-γ (IFN-γ) in the treated group were significantly higher than those in the control group (p &lt; 0.05) on days 1 and 60. The results indicate that maternal supplementation with trace minerals is a promising approach for producing highly disease-resistant calves and enhancing calf immunity.

Calf morbidity, mortality, and management practices in dairy farms in Jimma City, Southwestern Ethiopia

BackgroundThis research aims to determine the incidence of calf morbidity, mortality and its potential predisposing factors in the first six months of life. Morbidity and mortality of dairy calves are persistent problems for dairy farmers worldwide. For effective control and prevention programs on calf health, it is imperative to estimate the extent of calf morbidity and mortality, and associated risk factors. Although few studies have investigated the epidemiology of calf morbidity and mortality in Ethiopia, comprehensive information is scarce in this area.MethodsData were collected through a cross-sectional survey and longitudinal follow-up on purposively selected dairy farms. A longitudinal study was conducted on 235 calves from birth to 6 months of age. Survival analysis methods using the Kaplan–Meier (K-M) method, and mixed effect Cox proportional hazard regression were employed to compute the life-to-event data on morbidity and mortality.ResultsFrom the 235 calves studied, 53 morbidity and 15 mortality events were recorded. This gives an overall morbidity and mortality incidence rate of 55 per 100-calf 6-months at risk (risk rate of 42.07%) and 14 per 100-calf 6-months at risk (risk rate of 12.97%), respectively. Diarrhea (13.84%) followed by pneumonia (8.97%) were the most common diseases that occurred in calves, respectively. Similarly, diarrhea (33.3%) and pneumonia (26.7%) were the leading causes of death. Dam parity (p < 0.001) and pen cleaning (p < 0.001) were significant predictors of calf morbidity. Dam parity (p = 0.007), calving status (p = 0.005), pen cleaning (p = 0.04), and floor type (p = 0.001) of houses were significantly associated with mortality. The hazard of diarrhea was significantly associated with sex (p = 0.003), first colostrum feeding time (p = 0.028), pen cleaning (p = 0.010), and breeding method (p = 0.013).ConclusionThe rates of morbidity and mortality reported in the study were higher than the economically acceptable, also affecting the welfare of the animals. The risk factors found need due attention in the management practices of dairy calves in Ethiopia.

Effects of supplementing colostrum beyond the first day of life on growth and health parameters of preweaning Holstein heifers

The preweaning period for a dairy calf is characterized by high morbidity and mortality rates, leading to financial losses for producers. Identifying strategies to improve the health and welfare of calves while reducing antimicrobial use continues to be crucial to the success of the dairy industry. The objective of this study was to determine the effects of feeding colostrum replacer (CR) to dairy heifer calves beyond d 1 of life on growth, serum IgG, the incidence of diarrhea and bovine respiratory disease (BRD), and the risk of mortality in the preweaning period. At birth, Holstein heifer calves (n = 200; 50/treatment) weighing 40.7 ± 0.35 kg (mean ± SE) were fed 3.2 L of CR (205 g IgG/feeding) at 0 h and 12 h of life. Calves were then randomly assigned to 1 of 4 treatments: 450 g of milk replacer (MR) from d 2 to 14 (control, CON), 380 g of CR + 225 g of MR from d 2 to 3, then 450 g of MR from d 4 to 14 (transition, TRAN), 45 g of CR + 450 g of MR from d 2 to 14 (extended, EXT); or 380 g of CR + 225 g of MR from d 2 to 3, then 45 g of CR + 450 g of MR from d 4 to 14 (transition + extended, TRAN+EXT). Each treatment was reconstituted to 3 L and fed twice daily. All CR treatments were fed using bovine-derived CR containing 27% IgG. From d 15 to 41, all calves were fed 600 g of MR reconstituted to 4 L twice daily. Body weight was recorded at birth and every 7 d until study completion on d 49. Blood samples were taken daily until d 7 to evaluate serum IgG and then every 7 d until d 49. A health assessment was performed daily to evaluate calves for BRD and diarrhea. Data were analyzed using mixed linear regression, mixed logistic regression, and survival analysis models in SAS 9.4. Serum IgG concentrations were not affected by treatment for the study period. The EXT and TRAN+EXT groups had greater average daily gain (ADG) from d 7 to 14 (0.14 kg/d) and the TRAN group had greater ADG from d 14 to 21 (0.11 kg/d), compared with CON. There was no association of treatment with the odds or the duration of a diarrhea bout. However, provision of CR to the TRAN and EXT calves was associated with a reduced hazard of diarrhea compared with CON calves. Furthermore, TRAN and EXT calves have a lower hazard of mortality compared with CON calves, with TRAN and EXT calves had a 2.8- and 3.8-times lower hazard of mortality, respectively. Our findings suggest that the supplementation of CR to dairy calves positively affects ADG, and reduces the hazard of diarrhea and mortality during the preweaning period. Future research should look to further refine the supplementation strategy of CR to calves and explore the mechanism of action.

Preliminary exploration of the health and behavior around the time of transportation of beef × dairy calves and Holstein bull calves 3 days of age or younger in the western United States

In the western United States, it is common practice for dairy and beef × dairy calves to be sold and shipped within the first few days of life, making transportation one of the first challenges that a calf will experience. To date, no published research has examined the effects of calf transport within the western United States. The objectives of this observational study were to describe the health status of calves leaving the source dairy, characterize transportation conditions and calf behavior during transportation, and determine if age at transportation and transportation duration are associated with dehydration, blood glucose and lactate, and behavior. An observational study was performed on 2 source dairies in the western United States. Initial enrollment consisted of dairy bull calves and beef × dairy calves (n = 126 total) across 16 transport cohorts which were sold and transported to separate calf-raising facilities approximately 80 km from the source dairy. Health exams and measurements were performed on all study participants 2 to 3 h before transport and ≤2 h after transport. Two researchers performed health exams using the Wisconsin calf health score, which included clinical respiratory scores, lung ultrasound, and fecal, navel, and joint scores. Hydration status was assessed using skin tent duration. Blood samples were collected and immediately analyzed for blood glucose and lactate using glucose and lactate meters. Accelerometers were attached at the source dairy on ≤10 calves in each of the 16 transport groups to record movement and behavior during transport (n = 90 had accelerometers attached). Results showed that about half of calves (49%) were identified with at least one health abnormality before transport. Researchers found an association between age and dehydration status in which calves <24 h of age were more likely to be dehydrated compared with calves 1 d of age. Additionally over half of the calves (56%) were identified as dehydrated after transport. To the authors' knowledge, this is the first observational study that investigates the effects of transportation on dairy bull and beef × dairy calf health and welfare in the western United States. Our findings support the need for improved management and decision making before transporting calves to reduce the negative effects of transport.

Effect of maternal bovine appeasing substance on health and performance of preweaned dairy calves

This study aimed to evaluate the impacts of a maternal bo­vine appeasing substance (MBAS) administered to preweaned Holstein calves on their health and performance. In total, 410 calves individually allocated were enrolled (Treatment, n = 205; Control, n = 205). Treated calves received a topical application of MBAS to the nuchal skin (2.5 ml) and the skin above the muzzle (2.5 ml) at one day of age and then every 14 days until weaning at 60 days of life. An extra dose was ap­plied when calves were moved from hutches to collective pens at approximately 100 days of age. Calves allocated to the control group did not receive any kind of treatment. MBAS re­duced the incidence of diarrhea (treatment = 58.6% vs control = 70.8%; P = 0.01) as well as mortality risk (treatment = 2.4% vs control = 7.8%; P = 0.02). Furthermore, calves treated with MBAS had greater (P = 0.002) body weight 7 days after calves were moved from the hutches to the collective pens. There­fore, the use of MBAS during the preweaning period appears to be an effective strategy to improve health and growth of dairy calves.

406 Awardee Talk: Extended Effects of Sequential Weaning and Backgrounding Management in Southeastern U.S. Beef Calves on Performance, Health, and Immunological Responses Through the Feedyard

Abstract Understanding post-weaning management strategy impacts on calf performance and health can help producers add value to their operations and further strengthens the viability of the beef supply chain. A series of research and Extension studies were conducted to: 1) validate perceptions and determine motivations for pre- and post-weaning calf management strategies used in Southeast US cow-calf operations and 2) assess the collective effects these practices have on calf health and performance through the feedyard phase. An interactive, online survey (n = 214 responses) was distributed to Alabama beef producers to assess factors influencing the use of pre- and post-weaning management and management systems. Key challenges producers face in their operations who practice managed weaning and backgrounding strategies include input costs, land availability and market predictability. Developing demonstration data models to address cost-benefits of weaning and backgrounding may help producers evaluate areas of challenges identified in this survey. Subsequently, a two-year study was conducted using 427 Angus-crossed steer calves (294.2 kg) from three Auburn University research farms. Calves were assigned to one of three weaning methods for a 14-d experimental period: fenceline, nose-flap, or abrupt weaning. Response variables included initial and final body weight following the 14-d period, vaccination, and acute phase protein response. In both years of the study, fenceline weaned calves had the greatest average daily gain at 1.08 kg/d (P &amp;lt; 0.0001) and abruptly weaned calves had the lowest average daily gain losing 0.15 kg/d during the 14-d observation period. After the weaning study, calves were brought to a centralized farm and began a 60-d backgrounding period where they were assigned to one of three nutritional management strategies in a 3×3 factorial design: cool-season baleage, bermudagrass hay, or grazing mixed warm-season annuals. All diets were supplemented with 1% BW of DDGS. Body weights and blood samples were again collected throughout the backgrounding period. In the backgrounding period, fenceline weaned calves had the greatest average daily gain (P = 0.02) in the first 30 d of the backgrounding period regardless of backgrounding diet type. Calves fed the hay-based diet also had a greater average daily (P &amp;lt; 0.0001) than both the grazing and baleage groups in the first 30d of backgrounding. From d 30 to 60 of backgrounding in each year, steers on grazing and baleage diets supported greater ADG (P &amp;lt; 0.0001) than hay diets during the last 30-d of the backgrounding period (0.74 kg/d and 0.77 kg/d vs. 0.31 kg/d, respectively). Following the backgrounding, steers were transported to a commercial feedyard where they remained for the finishing phase. Effects of backgrounding management on feedyard performance were only observed during the first 35d in the feedyard. Results indicate that weaning and backgrounding management strategies can influence calf performance during the transition period into the feedyard phase.

284 Supranutritional Mineral Supplementation During Pregnancy Alters Placental Blood Flow and Calf Mineral Concentrations

Abstract Fetal development is dependent on maternal nutrient status, and the maternal-fetal connection is mediated by the placenta. There are well-established nutrient requirements for gestating cattle aimed at promoting the health of dam and fetus; however, there is limited information on the impact of supranutritional nutrient availability on placental function and calf development. This study evaluated the effect of supranutritional mineral administration during gestation on uterine artery blood flow and calf mineral status. Angus and SimAngus cows (n = 52) were bred via artificial insemination. At d 60 of gestation, cows were assigned to treatment groups; an injectable group (INJ, n = 26) receiving a single subcutaneous mineral injection and access to free-choice trace minerals and a control group (CON; n = 26) having access to free-choice trace minerals. Liver mineral content was analyzed in a subset of cows (CON n = 10; INJ n = 6) at d 60 and 209 ± 1 of gestation. At d 139.5 ± 0.5 and 209 ±1 of gestation, uterine artery measurements were collected using Color Doppler ultrasonography. Placental cotyledons, liver tissue, and blood samples were collected from a subset of animals at calving (n = 11; CON, n = 5; INJ, n = 6). Analysis revealed a TRT*day interaction at d 139.5 ± 0.5 for circulating Co concentrations which were greater (P = 0.05) and Se tended to be greater in INJ cows (P = 0.09) compared with CON cows. Circulating Zn concentrations tended to be decreased at d 209 ± 1 (P = 0.06) in INJ cows compared with the CON cows. Circulating Cu tended to be increased (P = 0.09) and Mn was decreased (P = 0.04) in INJ cows throughout the study. Hepatic Fe concentrations were decreased in INJ cows (P = 0.01) at d 209 ± 1. At d 139.5 ± 0.5, non-gravid uterine artery area, diameter, and circumference were increased in the INJ cows (P &amp;lt; 0.006 ). Additionally, pulsatility index of the gravid uterine artery tended to be increased (P = 0.09) in the INJ cows. Blood and liver samples were collected from calves (CON n = 24; INJ n = 26) at 4 to 8 d post-calving to assess mineral concentrations. INJ calves had greater liver Se (P = 0.001), decreased Fe (P = 0.04), and tended to have increased Zn (P = 0.09) and Mn (P = 0.08) concentrations compared with CON calves. Finally, INJ calves tended to have greater serum Se concentrations (P = 0.09) compared with CON calves. Trace minerals have roles in immune function and impact overall calf health. These results indicate that supranutritional trace mineral administration during early gestation alters placental blood flow and improves calf mineral availability. This supplementation protocol may provide the opportunity to improve the health of future calf crops.

PSXIV-11 Evaluating the Inoculating Bacterial Communities Within the Bovine Dam and Neonate After Applying an Ablation Technique to the Dam Vaginal Microbiome Prior to Parturition

Abstract The vaginal microbiota (VM) is the first contact of the neonate with microorganisms, which can attribute to neonatal health outcomes. The effects of an altered VM at parturition on neonatal microbial inoculation and passive transfer success has not been evaluated. Betadine lavages (BL) are commonly used to mitigate bacterial infections within the reproductive tract by ablating the VM. Ablation of the VM prior to parturition decreases microbial competition during neonatal microbial colonization, increasing the likelihood for pathogen inoculation. Thus, this study aimed to determine if an altered VM impacts neonatal and dam microbial inoculating bacterial communities in beef cow-calf pairs. Cows (n = 12) were randomly assigned to either control (CON) or BL (BLG) treatment groups two weeks prior to calving. Treatment BL was infused into the anterior vagina weekly until calving. Samples (dam-vaginal swab, dam-udder swab, dam-haircoat swab, and calf-nasal swab) were collected within 24 hours of parturition and stored at -80°C. The vaginal bacterial community composition was determined through sequencing of the V3-V4 region of the 16S rRNA gene using the Illumina Miseq platform. Alpha diversity was compared via two-way ANOVA; beta diversity was compared via PERMANOVA. Taxonomic differences were evaluated using the LEfSe platform. Microbiota data were analyzed using the R software package. Serial BL prior to parturition did not alter the alpha diversity of the dam-vaginal (P = 0.42), dam-udder (P = 0.53), or dam-haircoat (P = 0.21) microbiota but did alter the calf-nasal microbiota (P = 0.03). Moreover, the beta diversity did not differ within the dam-vaginal (P = 0.66) or dam-udder (P = 0.56) between BLG vs. CON, but there was a trend within both the calf-nasal (P = 0.08) and dam-haircoat (P = 0.09) for BLG pairs to have increased variation compared with CON. Within the calf-nasal microbiota, BLG had increased relative abundance of Actinobacteria and a decreased relative abundance of Proteobacteria compared with CON. Interestingly, previously reported IgG data from this study showed there was no difference in passive transfer status between CON and BLG calves, represented by no significant differences in calf serum (P = 0.88). However, BLG dam colostrum had increased IgG concentrations compared with CON dams (P = 0.04). Together, these results are indicative of physiological insults (BL) prior to parturition leading to an increased immune response in BLG dams which altered colostrum IgG. Thus, neonatal colostrum consumption could drive immune responses against inoculating bacteria resulting in differing nasal microbial communities between BLG and CON calves. Overall, this research contributes to our understanding of the vaginal microbiota and its importance in neonatal health outcomes and highlights the need for further research in this area to better inform management practices for optimal calf health and productivity.

PSI-7 Vitamin a and D Pre-Exposure to Prime Reproductive Success in Breeding Beef Cows

Abstract Vitamins A and D are important for immunity, reproduction, and overall health. The need for supplementation is often overlooked in beef cattle production because it is assumed that beef cows receive adequate amounts of these micronutrients from their environment. However, there is an increasing incidence of vitamin A and D deficiencies in beef cattle due to challenges of environment, forage access and quality. It is well known that nutrition has a major effect on reproduction, but direct effects of vitamins A and D on beef cow reproduction and fertility are understudied. We previously reported increased rates of fertilization after co-culture of bovine embryos with vitamin A and D in vitro. The objective of this study is to determine how vitamin A and D supplementation in mid- to late gestation affects calving ease and birth weights of calves at parturition, as well as cow fertility at the following breeding. Angus and Angus crossbred females (Bos taurus) of first (n = 20) or second (n = 10) parity were selected based on pregnancy status and gestational age and then randomly assigned to treatment groups. Starting in October 2021, pregnant cows were injected monthly with either a vehicle (control) or a commercial supplement made up of 300,000 IU vitamin A and 45,000 IU vitamin D (Vitamin AD, Vet One; n = 15/ treatment group). Blood samples were collected before each injection for analysis of vitamin and hormone concentrations. All cows were monitored from January-April 2022 for signs of parturition to determine calving date and time, calving ease, birth weight, and to provide assistance if necessary. Serum samples were collected from the calves within 12 hours of parturition for analysis of vitamin D concentrations. There was no effect of vitamin A and D treatment on calving ease (Generalized Linear Model analyses; P = 0.58; 1.44 ± 0.2 treated, 1.29 ± 0.19 control group) or on birth weight (Generalized Linear Model; P = 0.52, 32.6 ± 1.24 kg treated, 33.8 ± 1.38 kg control group). Estrus synchronization, additional blood sampling, vitamin/vehicle injections, and artificial insemination (AI) was performed in late April 2022. Conception rates were determined by transrectal ultrasonography 30 to 40 days post-AI. Interestingly, 7 of 15 controls were determined to be pregnant by AI, while this improved to 10 of14 in AD-injected females (one female could not undergo AI due to late calving). Cows not pregnant by AI were pastured with a bull of proven fertility, and rectal palpation was used in the fall to determine overall pregnancy rates and any pregnancy loss. These data suggest a modest increase in serum vitamin A and D will improve pregnancy rates after AI. Additional studies should reveal if these treatments improve markers of calf health. Supported by The Oregon Beef Council (C. Bishop).

Comparable Evaluation of Nutritional Benefits of Lactobacillus plantarum and Bacillus toyonensis Probiotic Supplementation on Growth, Feed Utilization, Health, and Fecal Microbiota in Pre-Weaning Male Calves.

This study was conducted to investigate the impact of probiotic supplementation using Lactobacillus plantarum DSA 20174 and/or Bacillus toyonensis ATCC 55050 on growth performance, blood parameters, hematological measures, and fecal microbiota in pre-weaning Holstein calves. Thirty-two four-day-old male calves with a similar genetic background, weighing an average of 38.27 ± 0.12 kg, were randomly assigned to four groups. The groups consisted of a control group (CON) without supplementation, a group receiving B. toyonensis (BT) at 3 × 109 cfu/calf/day, a group receiving L. plantarum (LP) at 1 × 1010 cfu/calf/day, and a group receiving a combination of LP and BT (LP + BT) at half the dosage for each. The study found that calves supplemented with LP and LP + BT experienced significant improvements in average daily gain and final body weight compared to the control group. The LP + BT group showed the most positive effects on TDMI, starter intake, and CP intake. RBC counts tended to be higher in the probiotic groups, with the LP + BT group having the highest values. The LP + BT group also had higher total protein, albumin, globulin, and hematocrit concentrations. All probiotic groups showed higher serum IgG concentrations. Probiotic supplementation led to increased total bacterial count and decreased levels of E. coli, salmonella, and clostridium. The LP + BT group had a significant decrease in coliform count, while both LP and LP + BT groups had increased Lactobacillus populations. In conclusion, LP + BT probiotic supplement showed the most beneficial effects on growth, feed efficiency, blood constituents, and modulation of fecal microbiota composition.

Total and pathogen-specific serum Immunoglobulin G concentrations in neonatal beef calves, Part 2: Associations with health and growth.

The association of poor transfer of passive immunity (TPI) with negative health outcomes is extensively researched in dairy calves. However, few field studies have examined the effect of total and particularly pathogen-specific Immunoglobulin G (IgG) concentrations on pre-weaning health and growth of beef calves. Hence, the objective of this study was to determine the association of total and pathogen-specific IgG concentrations against selected pathogens associated with neonatal calf diarrhea (NCD) and bovine respiratory disease (BRD) and the odds of pre-weaning treatments, mortality, and the growth of newborn beef calves. A total of 420 serum samples from 1- to 7-day old beef calves born on 6 farms in Alberta, Canada, were available for this observational study. Serum samples were analyzed by radial immunodiffusion for total IgG concentration and by enzyme-linked immunosorbent assays for pathogen-specific IgG concentrations against Escherichia coli (E. coli), bovine Rotavirus (BRoV), Cryptosporidium parvum (C. parvum), Bovine Viral Diarrhea Virus (BVDV), Parainfluenza Virus Type 3 (PI-3), Bovine Respiratory Syncytial Virus (BRSV), and Bovine Herpesvirus Type 1 (BHV-1). Data about the individual dam- and calf-level risk factors, calf treatments, mortality, and birth and weaning weights were collected. Multivariable multilevel logistic and linear regression models were built to evaluate the association of total and pathogen-specific IgG concentrations with the odds of mortality and average daily gain (ADG), respectively, while their association with the odds of pre-weaning treatment was established by univariable logistic regression analysis. The odds of calves with IgG concentrations <10g/L of getting treated (OR 7.9, 95 % CI 2.7-23.7) and dying (OR: 18.5, 95 % CI: 3.7-93.4) were higher than for their counterparts (P<0.0001). Calves with IgG concentrations <24g/L also had higher odds of dying (OR: 10.1, 95 % CI: 2.6-40.2) and had lower ADG (-0.09kg, SE: 0.03, P<0.002) than calves with IgG concentrations ≥24g/L. Higher BVDV-specific IgG concentration was protective against mortality (OR: 0.97, 95 % CI: 0.96-0.99, P<0.001). This study highlights the negative association of inadequate TPI with health and growth of beef calves and thus, the need to refine protocols for dam vaccination and colostrum intervention in cow-calf operations to meet these higher IgG targets.

Reproductive and margin of safety of a fixed-dose combination injectable endectocide (0.2 mg/kg doramectin; 6.0 mg/kg levamisole hydrochloride) in cattle

We present a fixed-dose combination injectable (FDCI) solution for cattle formulated for a single subcutaneous administration at a dose rate of 1 ml/25 kg of body weight to deliver a dose of 0.2 mg/kg of doramectin and 6.0 mg/kg of levamisole hydrochloride (5.1 mg/kg base equivalent). This drug product is marketed in the United States under the tradename Valcor® and in Australia and New Zealand under the tradename Dectomax V®. Both levamisole and doramectin have histories of safe and effective use in ruminants, with safety margins of 3X and 25X, respectively. Three studies were conducted to demonstrate the safety of the new FDCI: margin of safety (Study 1), and reproductive safety in sexually nulliparous beef heifers (Studies 2 and 3). In Study 1, 3-month-old sexually intact male and female calves were given either saline (control) or 1X, 2X, or 3X FDCI on Days 0, 14, and 28. General health, clinical, and neurological observations were made throughout the study, and clinical and pathology evaluations were made at study end. Studies 2 and 3 demonstrated the reproductive safety of the FDCI on sexually nulliparous beef heifers using estrus synchronization and timed artificial insemination. Treatments of either saline (control) or 3X FDCI were administered to coincide with either folliculogenesis, implantation, organogenesis, early gestation, or late gestation. Reproductive safety was demonstrated by evaluating rates of conception, calving, abortion, and stillbirth, dystocia scores, and calf health. In all studies, the FDCI at 1X, 2X, or 3X dosages was well tolerated. In the margin of safety study, 3X calves showed increased incidence of salivation for up to 8 h post-dosing compared to other groups. Injection sites were palpable post-dosing in all three FDCI groups but resolved by Day 28 in all but one animal each in 2X and 3X. In the reproductive safety studies, the FDCI had no effect on conception, pregnancy, fetal development, or postnatal viability. Injection site swelling was increased in frequency and duration compared to controls. The studies demonstrate the safety of the new FDCI in cattle from 3 months of age and in reproducing heifers during all reproductive stages from folliculogenesis through gestation and up to a month post-partum.

Economic Comparison of Spring-Calving Dates and Cold Injury in the US Southern Plains

AbstractCalving date affects feed costs, calf weaning weights, marketing dates, labor availability, and, potentially, calf health. Employing recent estimates of calf weaning weights and surveys of producers, feedlot operators, and veterinarians, we model expected profits as a function of calving date. January-calving herds had the highest annualized net returns, a result driven by older weaning dates and heavier weaning weights. However, survey results show March and April were the most common calving months. This may be due to both weather and labor demand concerns. If weaning ages are restricted to 205 days, January calving was the least profitable because of higher feed costs.

Effect of Dietary Calcium Propionate Inclusion Level and Duration in High-Risk Newly Received Stocker Calves: Growth Performance, Body Fat Reserves, and Health

This study utilized fifty bull calves of the Continental × British crossbreed, with an average body weight of 147.0 ± 1.67 kg (BW), in a completely randomized design. The objective was to examine the impact of varying levels and duration of calcium propionate (CaPr) supplementation on the growth performance, body fat reserves, serum metabolites, and hemogram of high-risk newly received stocker calves. These calves were individually housed and fed a received diet for 56 d. The calves received the following treatments: (1) no CaPr (CTL), (2) 20 g CaPr/calf/d, (3) 40 g CaPr/calf/d, (4) 60 g CaPr/calf/d, and (5) 80 g CaPr/calf/d at 14, 28, 42, and 56 d after their arrival. Supplementing with 20 g CaPr from 28 to 56 d after arrival increased average daily gain (ADG) and BW (p &lt; 0.05), and DMI was not affected (p &gt; 0.05). This was reflected at 28 d with increases (p &lt; 0.05) in the ADG/DMI ratio and longissimus muscle area (LMA), and at 56 d in back fat thickness (BFT) and fat thickness at the rump (FTR). Also, with 20 g, blood urea nitrogen decreased (p &lt; 0.05), and increases were observed in the activity of gamma glutamyltransferase, monocytes (quadratic trend, p &lt; 0.07), and granulocytes % (quadratic effect, p &lt; 0.03). However, as the level of CaPr increased during the first 14 d after arrival, daily water intake, creatinine, total cholesterol, mean corpuscular hemoglobin concentration (linear effect, p &lt; 0.05), globulin, calcium, and mean corpuscular volume (linear trend, p = 0.08) increased, while alkaline phosphatase (linear trend, p = 0.07) and lymphocytes (linear effect, p = 0.05) decreased. Finally, the different levels of CaPr supplementation did not produce any significant effects or differences (p &gt; 0.05) in the remaining serum metabolites and hemogram (p &gt; 0.05). Ultimately, the inclusion of 20 g CaPr/calf/d in the diet for 28 d in newly received stocker calves increased ADG, ADG/DMI ratio, and LMA. If extended to 42 or 56 d, the increases in ADG persisted, but there was also a rise in body fat reserves (BFT and FTR) at the expense of a reduction in the ADG/DMI ratio. Furthermore, the different supplementation levels did not impact the reference range for most serum metabolites or the health of stocker calves.

The Effect of Probiotics in a Milk Replacer on Leukocyte Differential Counts, Phenotype, and Function in Neonatal Dairy Calves.

Probiotics have been investigated for many health benefits; however, few studies have been performed to determine the effects of oral probiotics on peripheral blood and respiratory immune cells in cattle. Our objectives were to determine changes in health and growth status, differential blood cell counts and function, and blood and lung cell function using flow cytometry and PCR in dairy calves fed a milk replacer with (PRO, N = 10) or without (CON, N = 10) the addition of probiotics to the milk replacer and dry rations from birth to weaning. Performance and clinical scores were not different between the treatment groups. Treatment-by-day interactions for peripheral blood leukocyte populations differed in cell number and percentages. A greater percentage of leukocytes expressed the cell surface markers CD3, CD4, CD8, CD11b, and CD205 on d 21 in CON animals. Lung lavages were performed on five animals from each treatment group on d 52. There were no differences between treatment groups for the expression of cytokines and Toll-Like Receptors as measured using Polymerase Chain Reaction, possibly due to the small sample size. Oral probiotics appear to affect peripheral blood immune cells and function. Their effect on overall calf health remains to be determined.