Calf Performance Research Articles

Growth Performance and Microbial Activity Positively Responded to Interactive Effect of Nitrogen and Phosphorus in Young Holstein Dairy Calves.

We hypothesized that nitrogen (N) and phosphorus (P), as two pivotal nutrients that contributed to the growth of growing animals, may have interactive effect on growth performance and microbial development in young calves. For this purpose, feeding two starter protein contents (20% [20CP] vs. 24% [24CP], DM basis) and two phosphorus supplementation levels (0.35% [0.35P] and 0.70% [0.7P], DM basis) was evaluated on growth performance, health indicators, digestibility of nutrients and microbial protein synthesis (MPS), the latter estimated from urinary purine derivatives (PDs). Forty-eight female Holstein calves (3 days of age) were assigned randomly to the following treatments: 20CP-0.35P, 20CP-0.7P, 24CP-0.35P and 24CP-0.7P (n = 12, each). Milk feeding schedule was identical among treatments until weaning (d 59), but study lasted until d 73. Feeding 24CP compared to 20CP diet tended to improve starter intake, increased average daily gain (ADG) during pre-weaning period (p < 0.05), and final body weight (p = 0.01). Higher P supplementation has marginal effect on starter intake but improved ADG (pre-weaning; p = 0.02) and microbial activity by greater MPS (p = 0.02) compared to 0.35P. The greatest starter intake, the most favourable general appearance score, the highest withers height, the highest hip height, the greatest organic matter and neutral detergent digestibility, and the greatest MPS were found when calves fed diets contained 24CP along with 0.7P in starter. Based on the current study results, N and P have separate effects on the growth performance of young calves; however, their positive interaction can be attributable to growth performance and microbial development, especially during the pre-weaning period.

Effects of saccharomyces cerevisiae fermentation products on growth performance, fecal short chain fatty acids, and microbiota of pre-weaning calves.

This research aims to explore the effects of incorporating saccharomyces cerevisiae fermentation products (SCFP) on growth performance, nutrient digestibility, antioxidant capacity, fecal SCFAs, and microbial composition of pre-weaning calves. Twenty Holstein calves, 10 days old and weighing an average of 48.63±0.91 kg, were randomly assigned to either the control group (CON) or the SCFP group, with 10 calves in each group. The CON group received only a basal diet, while the SCFP group received the starter diet supplemented with 5 g/head/d of SCFP products (NutriTek, Diamond V Cedar Rapids, IA 52404, United States). The pre-trial period lasted for 5 days, followed by a main experimental period of 45 days. The SCFP group had significantly higher final weight, ADG, and FE compared to the control group (p < 0.05). Moreover, the SCFP group exhibited increased apparent digestibility of DM, CP, EE, ADF, Ca, and P (p < 0.05). Additionally, supplementation with SCFP led to elevated content of GH, IGF-1, and GLP-1 in serum. The inclusion of SCFP also raised serum CAT content and reduced serum MDA content in pre-weaning calves. Furthermore, SCFP supplementation influenced the composition of intestinal microflora by decreasing Actinobacteriota abundance and increasing the abundance of Ruminococcus, Lachnospiraceae_AC2044_group, Parabacteroides, and Butyricimonas. The addition of SCFP has a positive impact on the growth performance, nutrient digestibility, antioxidant capacity, and intestinal microflora composition of pre-weaning calves.

Growth performance of neonatal calves fed milk replacer 2 vs. 3 times per day.

Several calf studies demonstrated growth advantages when feeding greater protein and/or milk solids amounts, however, studies comparing 2 times per day vs. 3 times per day feeding are limited. The study objective was to evaluate feeding 2 times per day vs. 3 times per day thereby increasing milk solids intake. Forty 2- to 5-d old Holstein bull calves were blocked by body weight (BW) and randomly assigned to 1 of 2 treatments (N = 20/treatment) using a randomized complete block design. Treatments were 1) 2×: milk replacer (MR) fed 2 times per day; and 2) 3×: MR fed 3 times per day for increased solids intake. The MR was fed at 15% solids at 0630 and 1800 hours and the 3rd 3× feeding was at 1200 hours. Calves on 2× were fed MR at 0.567 kg/d for days 1 to 14, increased to 0.85 kg/d for days 15 to 35, and reduced to 1 time per day at 0.425 kg/d for days 36 to 42 to facilitate weaning at 42 d. Calves on 3× were fed MR 0.851 kg/d for days 1 to 14, increased to 1.275 kg/d for days 15 to 35, and reduced to 1 time per day at 0.425 kg/d for days 36 to 42 followed by weaning. Calf starter (CS; amounts and orts weighed daily) and water were offered for ad libitum intake. Initial BW was not a significant covariate and final BW (81.5 and 80.9 kg, for 2× and 3×, respectively) was similar. A treatment-by-week interaction (P < 0.01) indicated variable BW gains during the study with calves fed 3× demonstrating greater BW during weeks 4 (P < 0.10) and 5 (P < 0.05) compared with calves fed 2×. However, BW gains for calves fed 3× were reduced (P < 0.05) during the weaning period resulting in similar BW gains (36.8 and 36.4 kg) at the study end. Intake of CS (0.65 and 0.46 kg/d) was lower (P < 0.04) for calves fed 3× compared with calves fed 2×. Feed conversions (0.64 and 0.58 kg/kg) were greater (P < 0.02) for calves fed 2× compared with 3× fed calves. Calves fed 2× had less (P < 0.01) scours (fecal score = 0; 34.3 and 29.7 d) compared with 3× fed calves. Providing an additional MR feeding demonstrated minimal BW gains due to lower CS intake. Providing greater MR intake using a 3rd daily feeding reduces CS intake that can inhibit transition to dry feed when weaning calves.

Preweaning Megasphaera elsdenii Supplementation in Dairy-Beef Calves: Impact on Performance, Behavior, and Rumen Development

This study evaluates the effects of an oral probiotic capsule containing a live culture of M. elsdenii NCIMB 41125 on performance, feeding behavior, rumen pH VFA, and development of dairy-beef crossbred calves. Thirty-one male dairy-beef crossbred calves (Holstein x Angus; mean ± SD; 45.3 ± 7.1 kg; 8.2 ± 2.0 d old) were enrolled in a blinded, 76-d randomized trial. Calves were randomly assigned to one of 3 treatments: placebo, probiotic capsule administration on d 15, or probiotic capsule on d 15 plus a second capsule on d 39 of the study. Calves were housed individually with ad libitum access to water and calf starter and were fed 7L/d of milk replacer (1050g of powder/d) in 2 meals until d 41, then 3.5L/d in 2 meals until weaning on d 56. Behavioral observations were recorded in 1-min intervals using a wall-mounted camera. Rumen fluid samples were collected on d 14, 35, 49, 58, and 70, and analyzed for pH and VFA. Upon euthanasia on d 77, forestomach weights were recorded, and rumen papillae dimensions were measured. Mixed linear models were used for statistical analysis. Probiotic treatment resulted in greater daily solid feed DMI and ADG, particularly during weaning and postweaning periods. Additionally, probiotic treated calves spent more time drinking water and tended to have lower rumen pH compared with control. Empty rumen weight and papillae area were greater in calves supplemented with the probiotic capsule on d 15 compared with the other treatments. These findings suggest that preweaning M. elsdenii supplementation enhances performance and rumen development in dairy-beef crossbred calves. However, the impacts of timing and number of capsule applications on rumen development and calf performance should be further investigated. Further research should also investigate the probiotic's impact on the rumen microbiome and fermentation dynamics throughout the rearing period using detailed microbiome analysis.

A meta-analysis approach to evaluate the effects of early group housing on calf performance, health and behavior during the preweaning period

This study aimed to evaluate the effects of early group housing on the performance, health, and behavior of dairy calves during the pre-weaning period using systematic and meta-analysis approaches. Peer-reviewed articles written in English that compared dairy calves individually and group-housed with performance, health, or behavior outcomes were collected from Web of Science, PubMed and CabDirect databases. The resulting articles (n = 850) underwent a PRISMA 4-step appraisal process, resulting in a final sample of 51 articles containing 85 studies. The weighted or standardized mean differences between individually and group [pair or group (with > 2 calves)] housed calves were analyzed for each variable using the Der-Simonian and Laird methods. Heterogeneity between calf housing systems was evaluated by the chi-squared test and I2 statistics. A meta-regression analysis was conducted to identify categorical covariate effects for variables with high heterogeneity. Most of the studies included in this review evaluated female calves (45.8%) weaned at 8 weeks old (52.6%). Housing systems were mainly paired housing (55.3%), followed by groups of 3 to 6 calves (30.65) and groups of 7 to 15 calves (4.7%). We did not find studies with comparable outcomes for more robust health parameters (as occurrence of diseases), only blood parameters, that were not influenced by the housing system (P > 0.05). But, weight gain and feed intake parameters were higher (P < 0.05) in group-housed calves. Through the meta-regression, we found that average daily gain was positively affected (P < 0.05) by the group housing in studies with calves housed in small pen areas (<1.5 m2 per calf). Group-housed calves presented more active behaviors (feeding and playing) and less stress-related behaviors (self-grooming and interacting with the pen) than individually-housed calves. The behavioral tests most used were novel object, human approach, novel environment, and social tests. Individually-housed calves presented fewer vocalizations on these tests and spent more time interacting with humans during the human approach test than group-housed calves. Our findings provide consistent evidence that group housing improves the welfare of dairy calves; however, the effects on health parameters are still scarce and unclear.

Long-term effects of transition milk feeding on feed intake, growth performance, feeding behavior, and oxidative status of Holstein calves

This study investigated the long-term effects of feeding 5-d transition milk (TRANS) compared with milk replacer (MR) on parameters, including intake, growth, feeding behavior and oxidative stress. Fifty Holstein calves (30 females and 20 males) were fed either 12 L/day TRANS or MR for the first 5 d after an initial colostrum feeding of 3.5 L. Thereafter, all calves were fed with 12 L of MR/d (140 g/L) and were gradually weaned starting in wk 8 until wk 14. Throughout the 14 wk the calves had unrestricted access to concentrate (up to 9.8 kg/calf/day), hay, and water. After weaning all heifers were fed a total mixed ration for young cows. Oxidative status was assessed in blood samples from birth to first insemination. Parameters assessed included the ferric reducing ability of plasma (FRAP) for antioxidant capacity and the concentration of reactive oxygen metabolites by the dROM (detection of reactive oxygen metabolites) assay. In addition, the activity of glutathione peroxidase (GSH-Px), oxidative damage in the form of lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and as advanced oxidation protein products (AOPP) were measured. An oxidative stress index (OSi) was calculated: dROM/FRAP x 100. Total protein (TP) concentration was also quantified via the Bradford assay. The only significant difference in feeding behavior between the 2 treatment groups was a higher concentrate intake by the TRANS calves during the weaning phase. Body weight and ADG did not differ significantly between the TRANS and MR groups. TRANS calves showed a trend for fewer cases of health disorders. Markers of oxidative status, including TBARS, AOPP, GSHPx, FRAP and ROM, showed no treatment effects but varied significantly over time. Of note, the oxidative stress index as ratio between pro- and antioxidants in both groups peaked during weaning and then returned to baseline, suggesting an effective response to this transition phase Overall, the results indicate that feeding TRANS during the first 5 d of life had no long-term effect on the parameters studied as compared with MR feeding under the present rearing conditions. These results provide insight into the changes of oxidative status with age and confirm that the relatively high milk feeding level, slow and late weaning enables calves to adapt well to solely solid feed.

Performance, costs, and blood indicators of dairy calves fed diets containing soybean hull and whole or ground corn

Performance, costs, and blood indicators of dairy calves fed diets containing soybean hull and whole or ground corn

Effects of propolis extract administration on immune parameters, faecal consistency scores, and growth performance of Holstein-Friesian calves.

The purpose of the study was to investigate the effect of Ethanolic Extract of Propolis (EEP) administration on immune parameters, faecal consistency scores, growth performance, and feed efficiency of Holstein Friesian calves. A total of 24 calves were divided into two different groups, control (n = 12) and EEP (n = 12). Both groups consisted of 6 male and 6 female calves. The calves were fed milk amounting to 10% of their birth weight each day until they reached 60days of age. Additionally, they were given starter feed and dry hay once a day. Calves assigned to the EEP group received 4ml of EEP daily. Use of EEP increased (P < 0.05) the serum IgG and IgM levels at 2months of age compared to the control group. EEP also showed efficacy (P < 0.01) in reducing faecal consistency in calves throughout the study. The levels of IL-1β, IL-6, TNF-α and NF-κB expression in calves treated with EEP were lower (P < 0.05) throughout the EEP application period. On the other hand, IGF-1 mRNA transcript levels were (P < 0.01) higher in EEP group calves than in the control group. Furthermore, EEP-fed calves consumed less dry matter for 1kg of live weight gain during the weaning-4months (P < 0.01) and birth-4months (P < 0.05) periods. These results indicate that EEP supplementation, through its immunostimulatory effects, plays a crucial role in the control of neonatal calf diarrhoea. Growth and development as well as IGF-1, which stimulates growth in almost all somatic cells, was also significantly increased by EEP supplementation. The combined effect of the rich bioactive compounds found in EEP appears to have a significant impact on health and well-being, resulting in improved early life performance in dairy calves.

PSXIII-1 Sensory additives improved the recovery of commercially marketed and transported unweaned dairy beef calves at rearing farm arrival

Abstract Calf recovery after arrival at the rearing farm in unweaned calves is impaired by periods of stress, feed restriction and fasting during marketing and transportation. The use of feed additives to enhance intake at arrival could be a strategy to minimize those negative effects. A total of 72 calves (71.4 ± 1.72 kg) gathered in a commercial assembly center and transported 9 h to a rearing farm were used to evaluate the effect of a sensory additive (SA) on performance in calves fed 2 L of milk replacer twice daily at 12.5% and ad libitum concentrate feed. Calves were allocated in 8 pens and distributed in 2 treatments (4 pens/treatment): calves fed a concentrate without SA since the beginning of the study (arrival to the rearing farm after transport) until weaning (CON; n = 36); calves fed a concentrate containing SA (SEN; n = 36) from arrival until weaning. Calf body weight (BW) and pen intake were recorded weekly. On d 21 of the study, calves were partially weaned and only milk replacer was offered in the morning, and on d 28 all calves were completely weaned. The study lasted 35 d. Data were analyzed with a mixed-effects model. Average daily gain was greater (P = 0.04) for SEN calves compared with CON calves (0.68 ± 0.019 kg/d and 0.61 ± 0.019 kg/d, respectively). Final BW of SEN calves (95.5 ± 0.89 kg) tended (P = 0.06) to be greater compared with BW of CON calves (93.1 ± 0.89 kg). Finally, average concentrate intake was greater for SEN calves (0.89 ± 0.023 kg/d) compared with CON calves (0.79 ± 0.023 kg/d). Unweaned dairy beef calves receiving sensory additive improved concentrate intake and growth at farm arrival improving their recovery.

PSXI-2 Impact of flexible prepartum supplementation strategies on cow-calf and subsequent progeny feedlot performance

Abstract Implementation of minimal supplemental protein strategies during late gestation may have the potential to minimize any negative postweaning progeny performance while decreasing feed costs. A 3-yr study was conducted to evaluate the effects of mid- to late-gestation supplementation strategies on reproduction, cow body weight (BW), and calf performance in May-calving mature cows grazing upland native range. Cows received one of 3 supplementation strategies: 1) 0.227 kg/d of a 30% CP distillers-based supplement (HalfSupp), 2) 0.454 kg/d of a 30% CP distillers-based supplement (Supp), or 3) brief and intermittent supplementation of Supp at 0.454 kg/cow based on periods of acute environmental stress, such as snow cover, wet winter events, and is best described as flexible supplementation (Flex). Supplementation was initiated in December each year and terminated approximately 30-d prior to the start of the calving season in April. Across all 3 yr, average supplement feeding rate was 25.5, 50.9, and 5.4 kg/cow during the 112-d supplemental period, which resulted in average yearly prepartum supplemental costs of $27.30, 54.60, and 1.99 for HalfSupp, Supp, and Flex; respectively. After weaning, steers grazed sub-irrigated meadow with a dried distiller grain supplement until May. In May, all steers grazed sub-irrigated meadow without additional supplement until August/September when steers were shipped to West Central Research and Extension Center (WCREC). Steers were placed in a GrowSafe feeding system for the rest of the finishing feeding period. Each year, steers were slaughtered at a commercial facility (Tyson Fresh Meats, Lexington, NE) when estimated visually to have 1.3 cm fat thickness over the 12th rib as a group. Cow BW was not different (P = 0.86) at the initiation of supplementation in Jan. However, cows fed Half had a lighter (P &amp;lt; 0.01) BW at pre-calving and tended (P = 0.08) to have a lighter BW at pre-breeding than their counterparts. After a 45-d breeding season, pregnancy rates were not influenced (P = 0.91) by prepartum supplementation strategies. Prepartum supplementation strategies did not influence (P &amp;gt; 0.56) preweaning calf BW at birth, pre-breeding, and weaning. In addition, steer backgrounding BW was also not influenced (P &amp;gt; 0.63) by prepartum supplementation strategy of their dam. Upon entry into the feedlot, steer BW was not impacted (P &amp;gt; 0.84) by prepartum supplementation strategy of their dam. Feedlot performance (BW, average daily gain, and feed efficiency) was not influenced (P &amp;gt; 0.59) by prepartum supplementation strategy of their dam. After harvest, all carcass characteristics were not impacted (P &amp;gt; 0.11) by the prepartum supplementation strategy of the dam. Considering the cost for prepartum supplementation, feeding a protein supplement just during environmentally stressful periods during gestation appears to be a viable alternative to more conventional methods and reduces winter feed costs.

PSVIII-9 Effects of growth implants and timing of vaccination on calf immunity and growth performance

Abstract This study assessed calf growth performance and blood parameters of beef calves under different growth implants and timing of vaccination protocols. Crossbreed beef calves (n = 59) were stratified by birth body weight (BW) and age (41 ± 5.2 kg of BW and 70 ± 8 d of age) and randomly assigned in a split-plot design with implant strategy as the main plot and timing of vaccination as the subplot. The main plot (treatment) consisted of 3 implant strategies: 1) Synovex C (SC; n = 20; 100 mg progesterone/10 mg estradiol benzoate, or 2) Synovex One Grower (SG; n = 19; 150 mg trenbolone acetate and 21 mg estradiol benzoate; or 3) no implant (CON; n = 20). Subplot treatments were the timing of vaccination booster against bovine respiratory disease pathogens on 1) weaning (WV; n = 29) or 2) 7-d post-weaning (PWV; n = 30). Cow-calf pairs were treated alike in a single pasture during the pre-weaning phase, receiving the same vaccine (Bovi-Shield Gold One Shot and Ultrabac 7) on d 0 (implantation day) and booster time (WV or PWV). After weaning (approximately 187 d of age), calves were allocated in a single pen receiving ad libitum hay until d 60 post-weaning. Body weight and blood were collected on d 0, weaning, d 0 and 28 relative to vaccination booster, and d 60 post-weaning. Blood was collected to determine insulin-like growth factor (IGF-1), cortisol, and leptin concentrations and to perform a complete blood cell count. WV calves had decreased cortisol concentrations on booster day and 28 d post-vaccine (P = 0.01). Regardless of implant treatment, calves tended to have decreased IGF-1 concentrations 28-d post-vaccine booster (P = 0.09). An effect of treatment (P &amp;lt; 0.01) was detected for lymphocyte counts, with CON having greater concentrations vs. SG and SC calves. A treatment × timing of vaccination (P &amp;lt; 0.01) interaction was detected for monocyte counts, where SG-PWV calves had the greatest concentrations. A treatment effect (P &amp;lt; 0.02) was observed for eosinophil percentage, where SG had reduced percentages than CON, while SC was intermediate. An effect of treatment was detected for leptin (P &amp;lt; 0.01), with SG calves having the least, CON being intermediate, and SC the greatest concentrations. From d 0 to 60 d post-weaning, SG tended to have greater ADG (P ≤ 0.07) compared with CON, while SC was intermediate. On d 28 and d 35 post-weaning, calves implanted with SG were heavier (P ≤ 0.04) than the CON but not than SC. In summary, this study demonstrates that growth implants and timing of vaccination significantly affect both physiological parameters and growth performance in beef calves. Implanting calves with Synovex One Grower resulted in improved growth performance.

PSXI-22 Effects of a palatability enhancer and olive bioactives on performance and physiological status of veal calves after farm reception

Abstract Veal calves have to deal with several stressors early in life, such as transport and commingling with animals of unknown health histories from multiple different origins; making the reception a possible critical period where animals should adapt to all these challenges. Previous studies in unweaned rosée calves have shown that the use of feed additives (FA) to enhance intake and immunity at farm arrival could be a strategy to minimize the negative effects of stress and feed restriction during transportation. The aim of this study was to evaluate the effects of a palatability enhancer (PE) and olive bioactives (OB) on performance and serum biomarkers in veal calves. Dairy beef calves [n = 252; BVD-free; body weight (BW) = 44.6 ± 3.63 kg] coming from auction market were distributed in 3 treatments (84 animals/tr) during 8 wk: i) calves fed concentrate and MR without FA (negative control, NC); ii) calves fed concentrate and MR with a PE based on sweeteners (PE); and iii) calves fed concentrate with PE and MR with PE and OB (PEOB). On farm arrival animals were housed individually until 5 wk of age, when animals were grouped in pens of 4 calves. Performance was monitored during the trial and serum samples were collected 48 h after the mixing (25 animals/tr) to analyze several biomarkers related to immune system (MILLIPLEX MAP Kit) and energy status (BHBA). Performance data were analyzed with a mixed-effects model and serum biomarkers by One-Way Anova with Fisher’s LSD correction for multiple comparisons (normally distributed data) or by non-parametric Kruskal-Wallis test with Dunn’s correction (data not normally distributed). Final BW was greater (P = 0.01) in PE and PEOB groups compared with NC (+2.2 kg and +2.6 kg, respectively). Concentrate feed intake (FI) during first 4 wk tended (P = 0.06) to be greater in PEOB compared with NC (+15%); however, after grouping (wk 5 to wk 8), PE showed a ldecreased FI compared with NC (-9.5%, P = 0.01). Forty-eight hours after animal grouping, PEOB showed reduced concentration of tumor necrosis factor (TNF) α than NC and PE (P = 0.03). Moreover, PEOB and PE had a greater concentration of interleukin (IL) 36Rα (P &amp;lt; 0.05) and IP10 (P &amp;lt; 0.01) compared with NC. Besides PEOB tended (P &amp;lt; 0.15) to have decreased concentrations of MIP1α, IL1α, and BHBA compared with PE. In conclusion, the addition of a PE and OB improved the adaptation of veal calves after reception, resulting in greater final BW. The improvement in early FI and the immunomodulatory effect in challenging situations displayed by the treatments may partially explain the observed benefits.

311 Effect of feeding butyric acid on growth performance and metabolic indicators of dairy calves before weaning: A meta-analysis

Abstract This meta-analysis aimed to evaluate the effect of feeding butyric acid (BA) on growth performance and metabolic indicators in dairy calves. A literature search was conducted to identify in vivo research studies carried out on BA supplementation in dairy calves. Inclusion criteria were in vivo studies, dairy calves, weaning, BA, and inclusion doses of BA. Twenty-three papers with 80 data and 1,132 calves were selected. Data extracted included the number of calves in control and treatment groups and measures of variance of responses (standard error or standard deviation). The response variables were production performance including body weight (BW), average daily gain (ADG) feed efficiency (FE), and metabolic indicators including blood glucose and beta-hydroxybutyrate (BHB) concentrations. A random effect of model was used to examine the raw mean difference and standardized mean difference between BA supplementation and the control group. The analysis was conducted using the metafor package of Rstudio. Butyric acid moderately improved the growth performance and metabolic indicators responses of calves with substantial heterogeneity (59 &amp;lt; I2 &amp;lt; 73%, P &amp;lt; 0.01). Final BW and ADG were increased by 2.7 kg and 48.1 g/day, or &amp;gt; 0.6 and &amp;gt; 0.4 standard deviation units (P &amp;lt; 0.05), respectively. However, FE was increased by BA supplementation but not significantly different. For metabolic indicators, glucose concentration was greater with BA supplementation with &amp;gt; 0.4 standard deviation unit, (P &amp;lt; 0.05). However, BA supplementation did not affect the blood concentration of BHB (P &amp;gt; 0.05). In conclusion, the meta-analysis results demonstrated that BA constitutes an important energy source for dairy calves. Butyric acid is effective in promoting growth performance and intestinal health and, yet, increasing production profits.

363 Effects of supplementation of vitamin B complex on the performance of beef calves during a 42-d preconditioning program

Abstract The objective of this study was to evaluate the effects of supplementation of vitamin B complex on post-weaning performance of beef calves. The study was conducted during fall of 2023 at Eastern Oregon Agriculture Research Center (EOARC; Burns, OR). At weaning (d 0), 63 calves [Angus × Hereford; body weight (BW) = 252 ± 3.6 kg] were randomly assigned to 1 of 3 treatments: 1) Control, 2) VitB1, or 3) VitB2. Calves assigned to Control treatment served as a negative control and were not supplemented with vitamin B complex. Calves assigned to treatment VitB1 were supplemented at 1g/calf daily, while calves assigned to VitB2 treatment were supplemented at 2g/calf daily of vitamin B complex during the 42 d of preconditioning. Upon weaning processing, calves were allocated to 21 pens (3 calves/pen) and treatments were allocated to each pen (7 pens/treatment). Vitamin B complex [Vivalto, pantothenic acid (B5; 40,000 mg/kg), pyridoxine (B6; 20,000 mg/kg), folic acid (B9; 3,200 mg/kg), biotin (B7; 3,200,000 mcg/kg), cobalamin (B12; 320,000 mcg/kg); Selko USA, Indianapolis, IN] supplementation was offered at pen level beginning on d 1 and until the end of the preconditioning phase (d 42). Vitamin B complex was offered to calves assigned to vitamin B complex treatment mixed with 1.3 kg of dried distiller’s grains. Additionally, calves had free access to chopped alfalfa-grass hay mix and whole corn. Pen intake was recorded daily. On d 0, BW and blood samples were collected from all calves. Additional blood and BW were collected on d 1, 3, 7, 14, 21, 42 post-weaning. Body weights were used to calculate calf average daily gain (ADG) and blood samples were assayed for acute phase proteins (ceruloplasmin and haptoglobin). Additional blood samples will be analyzed for cortisol and vitamin B concentrations. Variables were analyzed considering pen as the experimental unit and pen(treatment) as a random effect. Blood variables were evaluated as repeated measures and effects of treatment, day, and treatment the interactions were analyzed with the MIXED procedure of SAS (SAS Inst. Inc., Cary, NC). Significance was set at P ≤ 0.05. No treatment effects (P = 0.98) were observed for final BW (283, 283, and 284 kg respectively for Control, Vit1, and Vit2) or for ADG (P = 0.53; 0.735, 0.795, and 0.747 kg/d respectively for Control, Vit1, and Vit2). Similarly, no treatment effects were observed for the acute phase proteins analyzed, ceruloplasmin (P = 0.66; 27, 30, and 33 µg/dL respectively for Control, Vit1, and Vit2) and haptoglobin (P = 0.41; 0.55, 0.62, and 0.59 mg/mL, respectively for Control, Vit1, and Vit2). Supplementation of vitamin B complex to beef calves post-weaning does not seem to affect calf performance, regardless of the level of supplementation.

182 Converting spring-born heifers into a summer-calving herd increases subsequent cow longevity and productivity

Abstract Developing replacement heifers is one of the most expensive and complex management decisions for a cow-calf producer, which also has long-term implications for profitability. The objective of this study was to determine the impact of converting spring-born heifers into a summer-calving herd on growth, reproductive performance, longevity, and productivity compared with early or late-born May heifers. Over a 3 yr period, Red Angus/Simmental crossbred heifers (n = 273) were utilized to determine the impact of converting March-born heifers (Convert; n = 90) to a May-calving herd compared with May-born heifers on reproductive performance, body weight (BW), and calf performance from a yearling to 5 yr of age. May-born heifers were retrospectively grouped into 2 different groups: heifers born in the first 21 d of calving as a heifer calf (Early; n = 123) or heifers born after the 21 d of calving as a heifer calf (Late; n = 60). Heifers were exposed to bulls for a 45-d breeding season with a bull-to-heifer ratio of 1:20. Heifers were synchronized with a single injection of prostaglandin F2α (5-mL i.m.; Lutalyse, Zoetis, Parsippany, NJ) 5 d after bulls were introduced in the pasture for breeding. Data were analyzed as a randomized design using the MIXED procedure (SAS Inst. Inc., Cary, NC, USA). All binomial data were analyzed using PROC GLIMMIX. Heifer served as the experimental unit with treatment and year developed set as fixed effects. Heifer BW at December, May, July, and pregnancy check (Oct) were greater (P &amp;lt; 0.01) for Convert heifers with no difference between Early and Late born heifers. Heifer BCS at pregnancy check was not different (P = 0.13) among heifer treatment groups. However, pregnancy rate tended (P = 0.08) to increase for Convert heifers with no difference between Early and Late born May heifers. After 5 yr of age, retention rate was increased (P = 0.04) in Convert cows compared with Early and Late May-born cows with no difference (P = 0.84) between the two May-born heifer groups. Total kilograms of calf weaned was greater (P = 0.04) in Convert cows than their counterparts with no differences (P = 0.94) between Early and Late May-born cows. This study implies that selecting replacement heifers from an earlier calving season for replacements in a later calving season increases the longevity and long-term productivity of the cowherd than selecting heifers within the same calving season. This may be even more important in resource-poor breeding environments that create reproductive challenges for heifers and rebreeding young cows.

330 Growth performance, incidence of scours, and plasma metabolites in beef × dairy crossbred calves transported at 2, 4, 8 and 14 d of age

Abstract Transportation can compromise health and production performance in young calves. Although widely accepted that the younger calves are, the greater the probability of negative outcomes, there still is a lack of evidence-based recommendations on the minimum age at transportation. Our objective was to evaluate the impact of transport age on growth performance, incidence of scours, and plasma metabolites over the first 28 d post-transport in Charolais × Holstein crossbred calves. Calves (n = 36) ages 2, 4, 8 and 14-d old were transported in summer from a commercial farm to an on-campus calf rearing facility (410 miles). Calf body weight (BW) was recorded before departure, on arrival and d 28 post-transport. Dry matter intake (DMI) and fecal scores were recorded daily. Blood samples collected prior to transportation, on arrival, and d 7 and 28 post-transport were used for targeted metabolomics analysis (Biocrates MxP Quant 500 kit). Growth performance and fecal score data were analyzed using PROC MIXED (SAS) whereas R was used for predictive modeling of metabolomics data. Over the 28-d period post-transport, DMI was greater (P &amp;lt; 0.01) for 14 d than 2 and 4 d old calves; however, it did not differ between 2, 4, and 8 d old calves. Average daily gain (ADG) and feed efficiency (FE) were also greater (P &amp;lt; 0.01) for 14 d than 2, 4, and 8 d old calves. During wk 1 post-transport, the total number of days calves had scours was least (P &amp;lt; 0.01) for 2 and 14 d, intermediate for 4 d, and greatest for 8 d old calves. During wk 2, the total number of days with scours was less (P &amp;lt; 0.01) for 8 and 14 d (average of 2 d) compared with 2 and 4 d old calves (5 d). Additionally, the total number of days calves had scours during the first 2 wk post-transport tended (P = 0.08) to be greater for 2, 4, and 8 d than 14 d old calves. However, during wk 3 and 4 post-transport, there were no differences (P ≥ 0.58) in the total number of days with scours across transport age. Arginine methylation, d 7 of measurements, carnitine uptake defect, phosphatidic acid 16:0:18:2, methylenetetrahydrofolate reductase, sodium, triglyceride 18:2:34:4, threonine, α-aminobutyric acid, and glycolithocholic acid 3-sulfate were the most important features in terms of predicting the occurrence of scours. Overall, DMI, ADG and FE were less for calves transported at 2, 4, and 8 d than at 14 d of age, which could partially be attributed to differences in the incidence rate of scours. In addition, several plasma metabolites could be good predictors of scours in transported calves.

PSII-5 Effect of short-term feeding of hemp (Cannabis sativa) on stress biomarkers in weaned beef calves

Abstract Hemp research is growing rapidly due to its health benefits for animals; however, there is little information on its effects on stress. The objective of this study was to determine the effects of hemp supplementation on stress biomarkers in beef calves during weaning. Calves (n = 12) were completely randomized into Control (CC: received commercial concentrates before and after weaning), Treatment 1 (CH: received commercial concentrates before weaning and 25 g of hemp diet after weaning), Treatment 2 (HC: received 25 g hemp diet before weaning and commercial concentrates after weaning) and Treatment 3 (HH: received 25 g hemp diet before and after weaning). The study lasted for 28 d; blood samples were collected at 7-d intervals for enzyme-linked immunosorbent assay. Plasma was analyzed for heat shock protein 90, cortisol, haptoglobin, total antioxidant capacity, and glutathione peroxidase. There was treatment x time interaction in cortisol concentrations, with the (CH) group showing the greatest concentration of cortisol (124.23 ng/mL) in wk 3. There was no significant (P = 0.0675) difference in total antioxidant capacity. There was a treatment x time interaction (P = 0.0009) in glutathione peroxidase concentrations, with the (HH) group showing the greatest concentration of glutathione peroxidase of 46.83 ng/mL in wk 2 and 47.57ng/mL in wk 3. There was no significant (P &amp;lt; 0.05) difference in heat shock protein and haptoglobin. We concluded that hemp supplementation could reduce weaning stress in beef cattle, thereby improving the productivity and performance of beef calves

Source-dependent effects of early-life zinc supplementation in milk on growth performance and starter intake of pre-weaned dairy calves

This study aimed to evaluate the effects of milk supplementation with different zinc (Zn) sources on growth rate, starter intake, diarrhea incidence, and nutrient digestibility in dairy calves during the pre-weaning period. Forty newborn Holstein heifer calves were assigned to four treatments: control (no Zn supplementation; CON) or supplementation with 80 mg/day Zn from zinc sulfate (Zn-Sul), chelated zinc (Zn-Bon), or zinc methionine (Zn-Met). The Zn supplements were provided via milk from days 3 to 14 of age. Body weight (BW) and starter intake (SI) were monitored until weaning on day 70. Serum metabolite concentrations were determined in blood samples collected on days 15 and 70. Fecal consistency index (FCI) and frequency of medical treatments were measured during the first 21 days of life. Apparent total tract digestibility (ATTD) was determined in the 10th week of life. Although the effects of Zn supplementation on BW gain or body measurements were non-significant, a tendency for treatment × time interaction on BW was observed, with variations among the experimental groups becoming more pronounced on days 56 and 70, showing higher values in Zn-supplemented calves compared to CON. SI was improved by Zn supplementation, with the greatest response in the Zn-Bon group. Compared to control, ATTD of organic matter, neutral detergent fiber, and starch tended to increase with Zn supplementation. Blood metabolites and FCI did not differ among the experimental treatments. Although no significant difference was detected between Zn-Met and CON, the frequency of medical treatment was significantly lower in Zn-Bon and Zn-Sul compared to CON calves. In conclusion, zinc supplementation in milk, particularly with the organic chelated zinc source (Zn-Bon), showed promising effects on increasing starter intake and reducing medical treatments, along with trends toward enhanced growth and nutrient digestibility in pre-weaned calves.

Effects of forage feeding to calves on performance, rumen fermentation and nutrient digestibility: A meta-analysis

The literature on whether or not to feed forage is marked by inconsistencies, largely due to various factors associated with forage inclusion in calf diets. To elucidate these factors, we conducted a 3-level meta-analysis to comprehensively investigate the overall effects of forage provision in young calves. We searched for studies published between 2000 and 2023 in Google Scholar, ScienceDirect, and X-Mol. Moderator analyses were performed to evaluate the effects of different forage sources, forage provision methods, starter forms, milk levels and forage levels on the heterogeneity of growth performance, rumen fermentation and nutrient digestibility outcomes in studies feeding forage to calves. Mixed-effect model was used to predict the relationship between forage level and performance. Funnel plot and Egger's test were used to determine publication bias. A total of 86 treatment comparisons from 36 articles were included in the final data set. The weighted mean difference (WMD) was used to evaluate the effect size, and the statistical heterogeneity of the effect size was estimated using Cochrane's Q test. The results showed that forage supplementation improved growth performance, structural growth, and development of rumen fermentation in calves. However, moderator analyses revealed that several factors, including forage source, feeding method, physical form of starter, milk feeding level and forage feeding level might contribute considerably to variability, resulting in significant heterogeneity in the effects of forage provision in calves. Larger effect sizes were found for oat hay (OH) supplementation rather than alfalfa hay (AH) or straw, feeding forage as a free-choice (FC) compared with a total mixed ration (TMR; defined as a mixture of calf starter and forage), especially when forage was fed as a FC resulting in higher total dry matter intake (TDMI) and body barrel. Forage supplementation was more effective in boosting calf growth in calves provided ground starter than in calves fed pelleted and textured starter. Greater effects were shown for AH supplementation than OH or straw in improving rumen fermentation parameters. Furthermore, compared with the preweaning period, the effect of providing forage on calves was more noticeable in the postweaning period. The results of the mixed-effects model analysis indicated that calves can be efficiently fed 12% of dry matter as forage during the preweaning period to support their growth and development. Meanwhile, 9% of dry matter might be the optimal level for feeding OH and straw to preweaning calves. More studies are essential to explore how different levels of AH dietary supplementation affects calves during the preweaning period, to improve the consistency and accuracy of the dose-response curve predictions. Overall, growth performance and rumen fermentation of dairy calves were affected by forage inclusion. Moreover, forage source, feeding method, physical form of starter, milk feeding level, and forage level are essential factors that result in different degrees of effect on the calf's performance and rumen fermentation.

PSVII-17 The effects of gamma-aminobutyric acid on growth performance, antioxidant capacity, rumen fermentation, and diarrhea in newborn calves before weaning

PSVII-17 The effects of gamma-aminobutyric acid on growth performance, antioxidant capacity, rumen fermentation, and diarrhea in newborn calves before weaning