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The objective of this study was to evaluate the effects of concentrate supplementation levels on performance and DM intake of early-weaned beef calves consuming annual ryegrass (Lolium multiflorium). The experiments were conducted at the UF/IFAS Range Cattle Research and Education Center, Ona, FL from January to May 2022. In experiment 1, treatments were two levels of concentrate supplementation (0.75% or 1.0% of BW) distributed in a randomized complete block design with four replicates. Concentrate was fed daily and had 18% CP and 78% TDN. Thirty-two Angus crossbred calves were weaned with 90 ± 14 kg BW at 76 ± 10 d of age and allocated to 1 of 8 annual ryegrass pastures (experimental units; 0.3 ha/pasture; 4 calves/pasture) with a continuous and fixed stocking rate. Herbage mass and nutritive value were estimated every 14 d and calves were weighed every 28 d. There was no difference in herbage mass (mean = 1.300 kg DM/ha; P = 0.44; SE = 0.46), herbage allowance (mean = 0.86 kg DM/kg LW; P = 0.66; SE = 0.03), CP (mean = 24.4%; P = 0.46; SE = 0.78), and in vitro digestible organic matter (mean = 77%; P = 0.49; SE = 1) concentration between treatments. There was a treatment × month interaction on ADG and the interaction occurred because calves receiving 1% BW had greater ADG than 0.75% BW in April (1.0 vs. 0.8 kg/d; P = 0.04; 0.03) but there were no differences between treatments in February, March, and May. In experiment 2, treatments were supplementation with 0.75% or 1.0% BW concentrate distributed in a complete randomized design with seven replicates. Fourteen steers calves (166 ± 17 kg BW) from experiment 1 were maintained in the same treatment, transferred to a drylot (1 steer/pen), and evaluated for forage and total DM intake, and in vivo DM digestibility. Ground annual ryegrass hay (11% CP, 58% IVDOM) was offered and adjusted to allow 10% refusals. There was no difference in forage DM intake (mean = 1.8 kg DM/d; P = 0.3; SE = 0.06) between treatments but calves receiving 1.0% BW had greater total DM intake (2.7 vs. 2.5 kg DM/d; P = 0.05; SE = 0.06) and in vivo DM digestibility (77 vs. 75%; P < 0.01; SE = 0.53) than 0.75% BW. Decreasing concentrate supplementation level from 1.0 to 0.75% BW may be a viable management practice to reduce cost of developing early weaned beef calves grazing annual ryegrass.

This study evaluated the associations of temperament with body weight (BW) and body condition score (BCS) change, ovarian structures, and inflammatory response in grazing Nellore cows assigned to a fixed-time artificial insemination protocol. Forty multiparous cows were kept on pasture and offered free-choice access to mineral/vitamin supplementation and fixed-time artificial insemination on d 0. Individual temperament scores (1-5) were assessed in the squeeze chute on d -30, where 1 are animals extremely calm and 5 extremely excitable. Cows with a chute score ≤ 3 were classified as ``calm'', and > 3 as ``excitable''. The BW and BCS were evaluated on days -30, 0 and 30, ovarian structures on days 0 and 14, and blood samples collected on days -30, -11, 0, 7, 14, 21 and 30. Excitable animals tended to have less (P = 0.09) BCS and lose more (P = 0.09) BCS from d -30 to 0. Temperament did not affect (P ≥ 0.12) BW and BW change. Excitable animals tended (P ≤ 0.10) to have smaller dominant follicles, corpus luteum (CL) diameters and CL volumes. Temperament did not affect (P ≥ 0.14) plasma concentrations of haptoglobin and ceruloplasmin, but excitable animals had less (P = 0.04) plasma concentrations of progesterone on days 7 and 14. Thus, excitable cows had less plasma progesterone concentrations and tended to have a greater decrease in BCS and had smaller dominant follicles and CL size.

This study evaluated the impacts of heat abatement during pre- and postpartum periods on physiology and performance of beef heifers and their calves. On day 0, 64 Brangus beef heifers (21 mo of age) were stratified by their initial body weight (BW; 454 ± 37 kg) and body condition score (BCS; 6.3 ± 0.28) and then were allocated into of 1 of 16 bahiagrass pastures (1 ha and 4 heifers/pasture). Treatments were randomly assigned to pastures (8 pastures/treatment) and consisted of heifers provided (SH) or not (NSH) access to artificial shade from day 0 to 33 (83 ± 4 d prepartum until 50 ± 4 d postpartum). Shade structures were removed on day 33. Calves were weaned on day 203 (119 ± 9 d of age), and then transferred to 1 of 16 drylot pens (3 to 4 calves/pen) and limit-fed a soybean hulls-based diet (3.25% of BW) until day 268. Data were analyzed as a complete randomized design using MIXED and GLIMMIX procedures for non-binary and binary variables, respectively. Heifer BCS on days 55, 133 and 203 were greater (P ≤ 0.01) for SH vs. NSH heifers. Plasma glucose did not differ (P ≥ 0.29), whereas plasma IGF-1 were greater (P ≤ 0.05) on days 55 and 133 for SH vs. NSH heifers. Calf BW was less (P = 0.05) for NSH vs. SH calves at birth, did not differ (P = 0.44) at weaning, and was less (P = 0.05) for SH vs. NSH calves on day 268. Plasma haptoglobin concentrations were greater (P = 0.05) and serum titers against bovine respiratory syncytial virus tended (P = 0.10) to be less for SH vs. NSH calves after vaccination. Serum titers against all remaining viruses did not differ (P ≥ 0.24) between treatments. Therefore, heat abatement during pre- and postpartum increased heifer BCS and plasma IGF-1 during late-gestation, increased calf birth BW, reduced calf post-weaning growth, and had minor changes to calf humoral immune function.

Objective The objective of this study was to evaluate nutritive value and fermentation characteristics of silage made with different plant components of sweet sorghum [Sorghum bicolor (L.) Moench] with or without microbial inoculation. Materials and Methods The experiments were conducted at Ona, Florida, in 2012 (Exp. 1) and 2013 (Exp. 2). In Exp. 1, treatments were the ensiling of different plant components, whole plant (leaves, stem, and inflorescence; WP), stem (stem only, ST), and bagasse (stem pressed to remove the juice, BAG). In Exp. 2, treatments were distributed in a factorial 3 × 2 arrangement with the same plant component treatments from Exp. 1 with or without microbial inoculant (B500). Results and Discussion In Exp. 1, BAG had greater (P Implications and Applications Sweet sorghum BAG had acceptable nutritive value and fermentation characteristics and can be used as forage for ruminants. Microbial inoculants may not improve the fermentation characteristics and nutritive value of sweet sorghum BAG silage.

This experiment evaluated the impacts of frequency of dried distillers grains (DDG) supplementation during late gestation on subsequent performance of cow-calf pairs. On day 0 (September), 120 multiparous Brangus cows (body weight, BW = 543 ± 4.6 kg; body condition score, BCS = 5.47 ± 0.09) were allocated into 1 of 20 bahiagrass pastures (6 cows and 4.7 ha/pasture). Treatments were assigned randomly to pastures (5 pastures/treatment) and consisted of cows offered no DDG supplementation (NOSUP), 1 kg/cow of DDG daily (7X), 2.33 kg/cow of DDG every Monday, Wednesday, and Friday (3X), or 7 kg/cow of DDG every Monday from day 0 to 77 (1X; total of 77 kg/cow of DDG dry matter for all supplemented cows). After calving (on average day 81 ± 7), all cow-calf pairs were managed similarly and remained on their respective pasture until calf weaning (day 342). Cow BW did not differ among treatments (P ≥ 0.13). Cow BCS on day 77 and at the start of the breeding season (day 140) were greater for supplemented vs. NOSUP cows (P ≤ 0.02) but did not differ among 1X, 3X and 7X cows (P ≥ 0.64). Overall plasma concentrations of glucose were greater for supplemented vs. NOSUP cows (P ≤ 0.05) but did not differ among 1X, 3X and 7X cows (P ≥ 0.44). Calving percentage, calving date, percentage of male calves at birth, and calf birth BW did not differ among treatments (P ≥ 0.15). Calf BW at weaning were lowest for NOSUP and greatest for 7X calves (P ≤ 0.05). Calf BW at weaning did not differ between 1X and 3X calves (P = 0.97) and both groups were intermediate (P ≤ 0.05). In summary, decreasing the frequency of DDG supplementation during late gestation did not impact pre- and post-partum performance of Bos indicus-influenced beef cows but reduced subsequent preweaning growth of their offspring.

This study evaluated the effects of maternal prepartum supplementation of dried distillers grains (DDG), with or without monensin addition, on maternal performance and physiology and offspring preweaning growth. On day 0 (approximately 197 ± 4 d prepartum), 150 multiparous, Brangus crossbred beef cows were ranked by their initial body weight (BW; 524 ± 51 kg) and body condition score (BCS; 5.0 ± 0.63), and then randomly assigned into one of 15 bahiagrass (Paspalum notatum) pastures (10 cows and 8.1 ha/pasture). Maternal treatments were randomly assigned to pastures (5 pastures/treatment) and consisted of no prepartum supplementation of DDG (NOSUP) or supplementation of DDG at 1 kg/cow/d (dry matter basis; DM) added with 0 mg (SUP) or 200 mg/d of monensin (SUPMO) from days 0 to 77. Effects of maternal treatment and maternal treatment × day of the study were not detected (P ≥ 0.63) for any forage data. Cow BCS on day 35 and near calving (day 77) did not differ (P ≥ 0.19) between SUP and SUPMO cows but both groups had greater (P ≤ 0.001) BCS compared with NOSUP cows. Cow BCS at the start of the breeding season (day 142) and on day 168 were the greatest (P

On day 0 of years 1 and 2, 64 Brangus crossbred heifers per year were stratified by initial body weight (BW) and age (mean = 257 ± 20 kg and 271 ± 22 d) and allocated into 16 bahiagrass (Paspalum notatum) pastures (4 heifers per pasture per yr). Treatments were randomly allotted to pastures in a 2 × 2 factorial arrangement of treatments (4 pastures per treatment per yr). Treatments consisted of concentrate dry matter (DM) supplementation at 1.50% of BW from days 0 to 100 (CON) or concentrate DM supplementation at 1.05% of BW from days 0 to 49 and 1.95% of BW from days 50 to 100 (SST). Then, each respective supplementation strategy was added or not with immunomodulatory feed ingredients from days 0 to 100 (OMN; 4 g/45 kg of BW). Heifers were assigned to an estrus synchronization protocol from days 100 to 114. Heifers detected in estrus from days 111 to 114 were inseminated (AI) 12 h after estrus detection. Heifers not detected in estrus were timed AI on day 114. All heifers were exposed to Angus bulls from days 120 to 210 (1 bull per pasture). Effects of supplementation strategy × OMN inclusion × hour were detected (P < 0.0001) only for intravaginal temperature from days 26 to 30, which were the least (P ≤ 0.03) for SST heifers offered OMN supplementation and did not differ (P ≥ 0.17) among all remaining treatments from 0830 to 1600 hours. Effects of supplementation strategy × OMN inclusion and OMN inclusion were not detected (P ≥ 0.12) for any variable, except for the percentage of heifers detected in estrus, which was greater (P = 0.01) for heifers supplemented with vs. without OMN. Total concentrate DM offered from days 0 to 100 and heifer BW on days 0 and 56 did not differ (P ≥ 0.49) between CON and SST heifers, but SST heifers were heavier (P ≤ 0.01) on days 100 and 210 compared with CON heifers. Body surface temperature on day 25 and plasma IGF-1 concentrations on day 75 were greater (P ≤ 0.04) for SST vs. CON heifers. Percentage of pubertal heifers, heifers detected in estrus, and pregnancy to AI did not differ (P = 0.36) between SST and CON heifers but the final pregnancy percentage was greater (P = 0.04) for SST vs. CON heifers. Thus, OMN supplementation decreased the intravaginal temperature of SST heifers but failed to improve their growth and reproduction, whereas the SST strategy improved body thermoregulation, growth, and final pregnancy percentage of heat-stressed Bos indicus-influenced beef heifers compared with a constant concentrate supplementation strategy.

This 2-yr study evaluated the effects of winter vs. year-round supplementation of Bos indicus-influenced beef cows on cow reproductive performance and impact on their offspring. On day 0 of each year (approximately day 122 ± 23 of gestation), 82 to 84 mature Brangus cows/yr were stratified by body weight (BW; 475 ± 67 kg) and body condition score (BCS; 4.85 ± 0.73) and randomly assigned to 1 of 6 bahiagrass (Paspalum notatum) pastures (13 to 14 cows/pasture). Treatments were randomly assigned to pastures consisting of winter supplementation with molasses + urea (WMOL), or year-round supplementation with molasses + urea (YMOL) or wheat middling-based range cubes (YCUB). Total yearly supplement DM amount was 272 kg/cow and supplements were formulated to be isocaloric and isonitrogenous (75% TDN and 20% CP). On day 421 (weaning; approximately 260 ± 24 d of age), 33 to 35 steers/yr were vaccinated against parainfluenza-3 (PI3) and bovine viral diarrhea virus type 1 (BVDV-1) and transported 1,193 km to a feedlot. Steers were penned according to maternal pasture and managed similarly until slaughter. Data were analyzed using the MIXED and GLIMMIX procedures of SAS. On day 217 (start of breeding season), BCS was greater (P = 0.01) for YMOL than WMOL cows, whereas BCS of YCUB did not differ (P ≥ 0.11) to both WMOL and YMOL cows. The percentage of cows that calved, calving date, birth BW, and preweaning BW of the first offspring did not differ (P ≥ 0.22) among maternal treatments. Plasma cortisol concentrations were greater (P ≤ 0.001) for YCUB steers at feedlot arrival (day 422) than WMOL and YMOL steers. Moreover, YCUB steers had greater (P = 0.02) and tended (P = 0.08) to have greater plasma concentrations of haptoglobin compared to WMOL and YMOL steers, respectively. Antibody titers against PI3 and BVDV-1 viruses did not differ (P ≥ 0.25) among maternal treatments. Steer BW at feedlot exit was greater (P ≤ 0.05) for YMOL and WMOL than YCUB steers. However, feedlot DMI did not differ (P ≥ 0.37) by maternal treatment. Hot carcass weight, yield grade, LMA, and marbling did not differ (P ≥ 0.14) among maternal treatments. Percentage of steers that graded low choice was enhanced (P ≤ 0.05) for WMOL and YCUB than YMOL steers. Maternal year-round supplementation of range cubes or molasses + urea either did not impact or decrease growth, immune function, and carcass characteristics of the offspring when compared with maternal supplementation of molasses + urea during winter only.

Objective Two experiments evaluated the effects of supplemental monensin on growth and physiology of early-weaned beef calves grazing ryegrass (Exp. 1) or bahiagrass (Exp. 2). Materials and Methods Brangus calves were weaned at 3 mo of age, stratified by sex and BW, and randomly assigned into 1 of 8 pastures (2 steers and 2 heifers per pasture per year) of ryegrass (Exp. 1; n = 2 yr) or bahiagrass (Exp. 2; n = 1 yr) from d 0 to 84. Treatments were assigned to pastures (4 pastures per treatment per year) and consisted of concentrate supplementation at 1 or 2% of BW (DM basis) in Exp. 1 and 2, respectively, with or without 20 mg of monensin/kg of DMI. Results and Discussion Herbage nutritive value and allowance did not differ (P ≥ 0.23) between treatments in Exp. 1 and 2, but herbage mass tended (P = 0.10) to increase by 5% for monensin versus control calves in Exp. 1. Calf overall ADG increased (P ≤ 0.005), whereas fecal coccidia egg count on d 84 decreased (P ≤ 0.0004), for monensin versus control calves in Exp. 1 and 2. Monensin supplementation tended (P ≤ 0.08) to increase plasma insulin concentrations in Exp. 1 and 2 and increased (P ≤ 0.03) plasma IGF-1 concentrations on d 56 in Exp. 1 and plasma urea nitrogen concentrations on d 84 in Exp. 2. Implications and Applications Supplemental monensin led to subtle changes to physiological parameters associated with energy metabolism, reduced coccidiosis infestation, and promoted the growth performance of early-weaned calves grazing ryegrass and bahiagrass pastures.

This 2-yr study investigated the timing of dried distillers grains (DDG) supplementation during the third trimester of gestation of Bos indicus-influenced beef cows and its impact on their offspring performance. On day 0 of each year (84 d before calving), Brangus cows (n = 84/yr; cow age = 8 ± 3 yr) were stratified by initial body weight (BW; 482 ± 75 kg) and body condition score (BCS; 5.3 ± 0.8) and assigned randomly to one of six bahiagrass (Paspalum notatum) pastures (experimental units; 14 cows/pasture). Treatments were assigned randomly to pasture (2 pastures/treatment/yr) and consisted of no prepartum supplementation (CON), 2 kg/d of DDG from day 0 to 42 (LATE42), or 1 kg/d of DDG from day 0 to 84 (LATE84). Following calving (day 84), cow-calf pairs remained in their respective pastures, and cows were offered sugarcane molasses + urea (1.82 kg of dry matter/cow/d) from day 85 until the end of the breeding season (day 224). On day 347, steer calves (n = 38/yr; 11 to 15 steers/treatment/yr) were weaned and transported to the feedlot (1,193 km). Steers were penned according to cow prepartum pasture and managed similarly until the time of harvest. BCS at calving was greater (P0.01) for LATE42 and LATE84 vs. CON cows but did not differ (P = 0.16) between LATE42 and LATE84 cows. Calving date, calving percentage, and birth BW of the first offspring did not differ (P ≥ 0.22) among treatments. However, LATE42 cows calved their second offspring 8 d earlier (P = 0.04) compared with CON and LATE84 cows. At weaning (first offspring), LATE84 calves were the heaviest (P ≤ 0.05), CON calves were the lightest, and LATE42 calves had intermediate BW (P ≤ 0.05). Steer plasma concentrations of cortisol and haptoglobin and serum bovine viral diarrhea virus type-1 titers did not differ (P ≥ 0.21) between treatments. Steer serum parainfluenza-3 titers were greater (P = 0.03) for LATE42 vs. CON steers, tended to be greater (P = 0.10) for LATE84 compared with CON steers, and did not differ (P = 0.38) between LATE42 and LATE84 steers. Steer feedlot BW, average daily gain, dry matter intake, and hot carcass weight did not differ (P ≥ 0.36) between treatments. Marbling and the percentage of steers grading choice were greater (P ≤ 0.04) for LATE42 vs. CON steers, whereas LATE84 steers were intermediate. In summary, different timing of DDG supplementation during the third trimester of gestation could be explored to optimize cow BCS and offspring preweaning growth and carcass quality.This 2-yr study evaluated the effect of the timing of dried distillers grains (DDG) supplementation during the last trimester of gestation in Bos indicus-influenced beef cows and the subsequent impact on their offspring. Brangus cows were allocated to one of the three prepartum treatments consisting of no prepartum supplementation, 2 kg/d of DDG for the first half of the last trimester of gestation, or 1 kg/d of DDG for the entire length of the last trimester of gestation. Prepartum supplementation, regardless of supplementation length, improved cow body condition scores at the time of calving. Calf birth weights were not affected by prepartum maternal treatment. Calves born to cows that received prepartum supplementation had greater weaning weight compared with no prepartum supplementation. However, weaning weights were improved to the greatest extent when calves were born to cows that received supplementation for the entire length of late gestation. Steer antibody response to parainfluenza-3 was improved with prepartum maternal supplementation, regardless of supplementation length. Furthermore, concentrating the total amount of supplement offered to the first half of the last trimester of gestation improved marbling and increased the percentage of steers grading choice compared with no prepartum supplementation or supplementation during the entire last trimester.

Effective early postnatal nutritional management is a crucial component of livestock production systems, and nutrient manipulation during this period has been shown to exert long-term consequences on beef cattle growth and physiology. Metabolic imprinting defines these biological responses to a nutritional intervention early in life that permanently alter physiological outcomes later in life. Early weaning has been used to study metabolic imprinting effects, given that it allows for nutritional manipulation of animals at a young age. This practice has been shown to enhance carcass characteristics in feedlot cattle and accelerate reproductive development of females. Another strategy to study the effects of metabolic imprinting without the need for early weaning is to provide supplements via creep feeding. Providing creep feed to nursing cattle has resulted in transient and long-term alterations in cattle metabolism, contributing to increased reproductive performance of developing heifers and enhanced carcass quality of feeder cattle. Collectively, results described herein demonstrate nutrient manipulation during early postnatal life exerts long-term consequences on beef cattle productivity and may be a strategy to optimize production efficiency in beef cattle systems.

This study aimed to evaluate the effects of dietary supplementation of rumen-protected methionine (RPM) on the body temperature and conception rate of Nelore cows exposed to high temperature and humidity index (THI) values. This study was realized on a commercial beef farm located in the north of Brazil (5º 31’ 39” S, 48º 49’ 18” W). At d-31, 31 days before the FTAI protocol, a total of 563 lactating multiparous Nelore cows were divided into two treatments, with three blocks each, the control group (CG) and methionine group (MG). Both groups were kept on tropical pastures and received a mineral supplement. The MG Group was supplemented with 3g RPM/100g during 77 days, and the expected mineral supplement intake of both groups was 100g/cow/day. Between d0 and d9 of the FTAI protocol, a subset of groups of cows (n=142) remained with a data logger attached to the progesterone device, to monitor intravaginal temperature (IT) every 30 min. During the period that the cows remained with the dataloggers the minimum, average, and maximum THI were 72.76, 78.02, and 83.28, respectively. Pregnancy diagnosis was realized 35 days after the artificial insemination and the conception rate was calculated as the number of pregnant cows/inseminated cows. Data were analyzed using the JMP GLIMMIX procedure. RPM supplementation did not affect the conception rate (CG = 64.36% vs. MG = 58.19%, P >0.05). Intravaginal temperature from day 1 to day 8, between 0630 and 2030 h and between 2200 and 0100 h were lower (P≤0.05) for MG in comparison with CG. The average and the maximum IT were, respectively, 38.94ºC, 40.88ºC for MG and 39.02ºC, and 41.38ºC for CG. In conclusion, the supplementation of rumen-protected methionine reduced the internal body temperature in Nelore cows submitted to high THI environments, during the hottest hours of the day, but does not affect the conception rate.

Fluctuations in nutrient intake and metabolism can be detrimental to beef cattle performance. Multiple studies evaluated the impacts of reducing the frequency of energy supplementation from daily (7X) to once (1X) or 3 times (3X) weekly during heifer development, calf preconditioning, and late gestation of beef cows on growth, reproduction, immune function, and progeny performance. Reducing the supplementation frequency from 7X to 3X weekly: (1) did not impact average daily gain (ADG; P = 0.52) but hastened (P ≤ 0.05) puberty and pregnancy attainment of beef heifers; and (2) reduced ADG (P = 0.02), increased (P ≤ 0.03) plasma indicators of physiological stress (cortisol and haptoblogin), and decreased (P ≤ 0.05) humoral immune response against pathogens associated with bovine respiratory disease (BRD) in preconditioning beef steers. Reducing the supplementation frequency from 7X to either 3X or 1X weekly during late gestation did not (P ≥ 0.21) impact cow prepartum body condition score and reproduction, but linearly decreased (P = 0.05) calf preweaning growth. The negative effects of infrequent energy supplementation may be attributed to greater fluctuations in plasma concentrations of insulin growth factor-1, glucose, insulin, and urea nitrogen compared to frequent energy supplementation. Later attempts to offset such negative effects of infrequent supplementation observed that neither increasing the supplementation amount (P ≥ 0.21) nor altering the timing of vaccination relative to weaning (P ≥ 0.12) prevented performance reductions in beef cattle supplemented infrequently. Only a gradual reduction in supplementation frequency for preconditioning calves prevented a reduction on growth and improved (P ≤ 0.05) the immune response against BRD pathogens. Combined, these results revealed that frequent energy supplementation during preconditioning of beef steers, development of replacement beef heifers, and late gestation of beef cows was required to optimize their growth, immunity, and reproduction, and the growth performance of their progeny.

This 2-yr study evaluated the combination of stair step supplementation strategy and OmniGen-AF inclusion on body thermoregulation, growth, and reproduction of Bos indicus-influenced beef heifers. Brangus heifers (n = 64/year) were stratified by BW and age (257 ± 20 kg; 271 ± 22 d) and allocated into 16 bahiagrass pastures. Treatments were randomly assigned to pastures in a 2×2 factorial arrangement. Treatments consisted of concentrate dry matter (DM) supplementation at 1.50% of BW from day 0 to 100 (CON) or concentrate DM supplementation at 1.05% of BW from day 0 to 49 and 1.95% of BW from day 50 to 100 (SST), which included or not OmniGen-AF from day 0 to 100 (OMN; 4 g/45 kg of BW). Heifers were submitted to an estrus synchronization protocol from day 100 to 114, inseminated from day 112 to 114, and exposed to bulls from day 120 to 210. Data were analyzed using SAS GLIMMIX procedure. Heifer BW did not differ (P ≥ 0.49) on days 0 and 56, but on days 100 and 210 it was greater (P ≤ 0.01) for SST vs. CON. Intravaginal temperatures from day 26 to 30, between 0830 and 1600h were least (P ≤ 0.03) for SST offered OMN and did not differ (P ≥ 0.17) among all remaining treatments. Body surface temperature on day 25 and plasma IGF-1 concentrations on day 75 were greater (P ≤ 0.04) for SST vs. CON. Percentage of pubertal heifers, estrus detection, and pregnancy to AI did not differ (P = 0.36) between SST and CON, but final pregnancy percentage was greater (P = 0.04) for SST. Thus, OMN decreased intravaginal temperature of SST heifers but failed to improve their growth and reproduction, whereas the stair step strategy improved body thermoregulation, growth, and final pregnancy percentage of Bos indicus-influenced beef heifers.

This study evaluated whether administration of lipopolysaccharide (LPS) at each trimester of gestation would alter the acute phase (APR) and metabolic responses to a postnatal LPS challenge in weaned heifers. Pregnant crossbred multiparous cows (n = 50) were randomized into prenatal immune stimulation (PIS; n = 24; administered 0.1 µg/kg BW LPS subcutaneously at 71 ± 2, 170 ± 2 and 234 ± 2 d of gestation) and saline (CON; n = 26) groups. From these treatment groups, heifer calves (n = 12 PIS and 11 CON) were identified at weaning (244 ± 3 d of age) to receive an LPS challenge. On d 0, heifers were fitted with vaginal temperature (VT) devices, jugular catheters, and moved into individual stalls. On d 1, heifers were challenged i.v. with LPS (0.5 µg/kg BW) at 0 h. Blood samples were collected and sickness behavior scores (SBS) recorded at 0.5 h intervals from −2 to 8 h and at 24 h relative to LPS challenge. Serum was analyzed for cortisol, cytokines, glucose, non-esterified fatty acids (NEFA), and serum urea nitrogen (SUN) concentrations. Baseline VT was lesser in PIS heifers from −11 to −5 h pre-LPS (treatment × time: P < 0.01) compared to the CON; however, the post-LPS VT response did not differ between treatments (P = 0.89). There was a treatment × time interaction (P < 0.01) for SBS with PIS heifers having lesser SBS from 0.5 to 2 h post-LPS compared to CON. There was a treatment × time interaction (P = 0.03) for cortisol with PIS heifers having greater cortisol at 0.5, 3, 3.5, 5.5 and 6.5 h post-LPS compared to CON. There were treatment × time interactions for the post-LPS cytokine responses (P ≤ 0.05). Specifically, PIS heifers had greater TNF-α from 1.5 to 2 h, yet less TNF-α at 3 h than CON (P < 0.01), and PIS heifers had greater IFN-γ from 3.5 to 5.5 h post-LPS than CON (P < 0.01). In contrast, IL-6 was less in PIS than CON heifers from 1.5 to 8 h post-LPS (P < 0.001). Glucose concentrations were greater in PIS heifers at −1 h, but less at 2, 3 and 5.5 h compared to CON (treatment × time: P < 0.01). Serum NEFA concentrations were greater (P = 0.04) in PIS than CON heifers. There was a treatment × time interaction (P < 0.01) for SUN with PIS heifers having greater SUN concentrations at −2, −1.5, 2, 3, 6.5 and 24 h than CON. These data demonstrate that in utero exposure to multiple low doses of endotoxin has lasting physiological and immunological effects when the offspring encounter a similar postnatal immunological insult.

This study evaluated the growth, physiology, and coccidiosis infestation of suckling beef calves provided monensin and grazing limpograss (Exp. 1) or bahiagrass (Exp. 2) pastures. Treatments were randomly assigned to pastures (4 pastures/treatment; 3 cow-calf pairs/pasture in Exp. 1; 4 pastures/treatment; 10 cow-calf pairs/pair of pastures in Exp. 2) and comprised of supplementation of 0.40 kg/d of soybean meal added or not with monensin (20 mg/kg of total DM intake) for 112 and 78 days before weaning in Exp. 1 and 2, respectively. In Exp. 1, supplement DM disappearance tended (P = 0.10) to be less for calves supplemented with vs. without monensin, but treatment × day and treatment effects were not observed (P ≥ 0.18) for herbage mass (HM), herbage allowance (HA), cow body condition score (BCS), calf average daily gain (ADG), calf plasma data, and fecal coccidia egg count. In Exp. 2, forage nutritive value, HM and HA, and cow BCS did not differ (P ≥ 0.43) between treatments. Supplemental monensin did not impact (P ≥ 0.78) plasma concentrations of insulin-like growth factor 1 but increased (P ≤ 0.05) calf overall ADG and plasma concentrations on day 78 and reduced plasma concentrations of urea nitrogen (PUN) on day 78 and fecal coccidia egg count on day 78 compared to calves provided no monensin supplementation. Hence, monensin supplementation successfully improved growth performance of creep-fed suckling beef calves, when herbage mass was not a limiting factor and coccidiosis infestation occurred.

Three experiments were conducted to evaluate the frequency of visits to a mineral feeder equipped with radio-frequency identification (RFID). In Exp. 1, twelve heifers (Braford, Brahman, and White Angus; n = 4/breed) were fitted with RFID ear tags and placed into a pasture with access to a RFID-equipped mineral feeder. Number of visits were greater (P ≤ 0.05) during daytime than the night period. Brahman and Braford heifers favored (P ≤ 0.05) daytime than night period. White Angus heifers did not display a specific period preference (P = 0.32). In Exp. 2, Black Angus and Brahman cows (n = 15 and 19, respectively) were placed into a pasture with access to a RFID-equipped mineral feeder. Brahman cows made more (P

Two experiments evaluated the effects of injectable trace minerals (ITM) administered 30 d before artificial insemination (AI) on body weight (BW), body condition score (BCS), ovarian structures, pregnancy rate, and components of the innate immune system of grazing Nellore cows. In Exp. 1, 20 multiparous cows (BCS = 4.3 ± 0.4, scale 1 to 9; BW = 388 ± 35 kg) were kept on marandu-grass pasture (Urochloa sp.) and offered free-choice access to a trace mineral supplement. Cows were stratified by BCS and BW and randomly assigned to 1 of 2 treatments: subcutaneous injection (6 mL/cow) of saline solution (0.9% NaCl) or ITM (Multimin 90; containing 60, 10, 5, and 15 mg/mL of Zn, Mn, Se and Cu, respectively) administered 30 d (d -30) before AI (d 0). Pregnancy diagnosis was evaluated on d 30, BW and BCS on d -30, 0 and 30, ovarian structures on d 0 and 14, and blood samples collected on d -30, -26, -22, -17, -11, 0, 7, 14, 21 and 30 for analysis of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), haptoglobin, ceruloplasmin and progesterone (P4). In Exp. 2, 573 multiparous cows (BCS = 4.8 ± 0.5; BW = 400 ± 35 kg) received free-choice access to a trace mineral supplement and were assigned randomly to 1 of 2 treatments (ITM or saline injection 30 d before AI). In Exp. 1, ITM did not affect (P ≥ 0.12) BW, BCS, corpus luteum (CL) diameter and volume, pregnancy rate, and plasma concentrations of haptoglobin, ceruloplasmin and P4 compared to saline injection. Administration of ITM increased (P ≤ 0.008) plasma concentrations of SOD on d -22 and -17 and GSH-Px on d -26 compared to saline. In Exp. 2, ITM tended to increase the pregnancy rate compared to saline injection for cows with BCS 5 (P = 0.36; 71.8 vs. 67.6 ± 3.5% respectively). Therefore, a single ITM injection 30 d before AI did not alter the body parameters, ovarian structures and acute phase response of grazing Nellore cows, but increased plasma concentrations of antioxidant enzymes, and tended to improve pregnancy rates to AI in cows with BCS

Made available in DSpace on 2019-10-06T15:22:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-06-01 Excitable temperament disrupts physiological events required for reproductive development in cattle, but no research has investigated the impacts of temperament on growth and puberty attainment in Bos indicus females. Hence, this experiment evaluated the effects of temperament on growth, plasma cortisol concentrations and puberty attainment in B. indicus heifers. A total of 170 Nelore heifers, weaned 4 months before the beginning of this experiment (days 0 to 91), were managed in two groups of 82 and 88 heifers each (mean ± SE; initial BW=238±2 kg, initial age=369±1 days across groups). Heifer temperament was evaluated via exit velocity on day 0. Individual exit score was calculated within each group by dividing exit velocity into quintiles and assigning heifers with a score from 1 to 5 (1=slowest; 5=fastest heifer). Heifers were classified according to exit score as adequate (ADQ, n=96; exit score ≤3) or excitable temperament (EXC, n=74; exit score>3). Heifer BW, body condition score (BCS) and blood samples were obtained on days 0, 31, 60 and 91. Heifer exit velocity and score were recorded again on days 31, 60 and 91. Ovarian transrectal ultrasonography was performed on days 0 and 10, 31 and 41, 60 and 70, 81 and 91 for puberty evaluation. Heifer was declared pubertal at the first 10-day interval in which a corpus luteum was detected. Exit velocity and exit score obtained on day 0 were correlated (r≥0.64, P