bluuebunny/crossref_metadata_2025 huggingface dataset:
88 Factors influencing mare milk composition and yield and foal digestive health
Authors: Pyles Morgan B , Fowler Ashley , Crum Andrea , Hayes Susan , Schendel Rachel , Flythe Michael , Lawrence Laurie
Published: November 2020

The microbial community that colonizes the gastrointestinal tract within the first few days of life can have significant impacts on the health of the foal. For example, proliferation of pathogens can lead to neonatal diarrhea. The factors influencing the establishment of the normal microbiome, which can provide pathogen resistance, are not well understood. This research aimed to evaluate factors influencing foal gut health including changes in foal fecal bacteria, mare milk composition and yield, and utilization of milk components by fecal bacteria from foals. We hypothesized that the maternal diet would alter milk yield and composition and as a result, will influence microbial colonization in the foal. To evaluate dietary influence on milk composition, mares (n = 16) were fed forage and either a concentrate with high nonstructural carbohydrate (NSC) or low NSC. Milk yield and composition were evaluated and relationships with foal fecal bacteria and diarrhea were explored. In addition, fecal samples collected from foals were used to enumerate select bacterial groups and isolate and identify carbohydrate-utilizing bacteria. We found that feeding mares a high NSC concentrate increased synthesis of milk carbohydrates and daily milk yield compared to mares fed a low NSC concentrate (P < 0.05). Microbes isolated from foal feces were capable of utilizing carbohydrates, such as lactose and galactooligosaccharides, as early as 12 h after birth. High milk producing mares had foals with fewer cellulolytic bacteria (P < 0.001). Foals with >1 bout of diarrhea had fewer cellulolytic bacteria (177 viable cells/g feces) compared to foals with no diarrhea (10,000 viable cells/g feces; P < 0.001). Fecal lactobacilli and lactate-utilizing bacteria were positively related to bouts of diarrhea (r=0.745 and r=0.555, respectively; P < 0.05). The gastrointestinal microbiome is changing rapidly in the foal and milk yield and composition appear to play an important role. The neonatal period may provide an opportunity to influence the microbiome and prevent gastrointestinal upsets.
59 Effects of exogenous glucocorticoid administration on leptin concentrations in perinatal dairy bull calves
Authors: Morris Camille , McCarty Keelee J , Long Nathan
Published: November 2020

Previous studies suggest a relationship between leptin and cortisol immediately postpartum is linked to improved feedlot efficiency on cattle exposed to perinatal stressors. The objective of the current study was to determine the effects of exogenous cortisol administration on circulating leptin concentrations in perinatal dairy bull calves. Within four hours of parturition, Holstein bull calves were randomly assigned to treatments and intravenously infused with low cortisol (LC; n = 9, 3.5 ug/kg of cortisol), high cortisol (HC; n = 9, 7.0 ug/kg of cortisol), or a sham infusion control (CON; n = 9, similar volume of saline). Calves were housed similarly and fed milk replacer (28% CP, 20% fat) three times daily. Blood collections were performed via jugular venipuncture using Z/9mL serum collection tubes (Sarstedt, Newton, NC) from d 0 to 5 of age. Serum samples were incubated for 1 h at room temperature then overnight at 4°C, centrifuged at 1800 x g at 4°C for 20 minutes, serum decanted, and stored long term at -20°C until analysis. At 5 d of age, calves were euthanized utilizing an overdose of sodium pentobarbital (Schering-Plough Animal Health, Union, NJ) and cerebral-spinal fluid (CSF) from the third ventricle of the brain was collected and stored at -80°C until analysis. All samples were analyzed for leptin concentrations via a previously-validated radioimmunoassay. Serum leptin concentrations were analyzed via repeated measures of ANOVA and CSF leptin concentrations via the GLM procedure of SAS (SAS Institute Inc., Cary, NC, USA). Serum leptin concentrations of HC and LC were decreased (P = 0.013) compared to CON, and d 0 was decreased (P < 0.001) compared to all other days of age. Cerebral-spinal fluid leptin concentrations of HC and LC were decreased (P = 0.005) compared to CON. In summary, exogenous cortisol administered to perinatal dairy bull calves reduced leptin concentrations in serum and CSF.
129 Presynchronization with Prostaglandin F2αand prolonged exposure to exogenous progesterone impacts estrus expression and alters fertility in beef heifers
Authors: Oosthuizen Nicola , Fontes Pedro , Lamb Cliff
Published: November 2020

To determine the effects of 2 presynchronization strategies in conjunction with delayed fixed-time artificial insemination (TAI) on pregnancy rates to TAI (PR/AI), 1,700 Angus beef heifers at 3 locations were enrolled in a completely randomized design with a 2×2 factorial arrangement of treatments. Within location, all heifers were randomly assigned to 1 of 4 treatments: 1) PG54 (n = 434), heifers received a 25-mg injection of prostaglandin F2α (PGF) 7 d prior (d -14) to the initiation of the 7-d CO-Synch + CIDR protocol wherein they received a 100-µg injection of gonadotropin-releasing hormone (GnRH) and a CIDR insert on d -7, a 25-mg injection of PGF at CIDR removal on d 0, and a second injection of GnRH concurrently with TAI 54±2 h later; 2) PG72 (n = 426), heifers were exposed to the same treatment as PG54; however, TAI was performed 72 ± 2 h after CIDR removal; 3) PG-CIDR54 (n = 422), same as PG54 but heifers received a CIDR insert on d -14 in addition to PGF; 4) PG-CIDR72 (n = 418), same as PG-CIDR54; however, TAI was performed 72±2 h after CIDR removal. Estrus detection patches were applied to all heifers on d 0 and were evaluated for activation at TAI. Pregnancy was diagnosed between 30 and 47 d after TAI. The percentage of heifers exhibiting estrus between d 0 and TAI was greater (P < 0.001) in the PG72, PG-CIDR54, and PG-CIDR72 treatments compared to the PG54 treatment (78.11, 86.59, and 91.09 vs. 31.05%, respectively). Furthermore, estrus response was greater (P < 0.001) in PG-CIDR72 heifers when compared to PG72. Pregnancy rates to TAI differed among treatments and were greater (P < 0.05) in the PG72 and PG-CIDR54 treatments when compared to PG-CIDR72 (48.8 and 50.4 vs. 38.4%, respectively), and were greater (P = 0.034) in PG-CIDR54 vs. PG54 (43.1%). Moreover, a tendency (P = 0.097) was determined on PR/AI between PG54 and PG72. In conclusion, presynchronization strategies and prolonged exposure to exogenous progesterone have the potential to alter estrus expression and improve fertility in replacement beef heifers.
181 Uterine and vaginal bacteria and cytokine profiles prior to artificial insemination between resulting pregnant and open postpartum beef cows
Authors: Poole Rebecca , Ault Taylor B , Myer Phillip R , Lear Andrea , Pohler Ky
Published: November 2020

Numerous factors impact reproductive success in beef cattle; however, the presence and activity of bacteria in the reproductive tract and its effects on fertility is relatively unknown. The objective of this study was to evaluate the relationship between reproductive tract bacterial communities and cytokine profiles prior to timed-AI (TAI) and compare between resulting pregnancy status at d30. Sixty-eight beef cows, 80 ± 2.6 d postpartum at TAI, were synchronized and subjected to TAI on d0. Pregnancy was diagnosed via transrectal ultrasonography on d30. Uterine and vaginal flushes were collected on d -21 and -2 for bacterial DNA extraction to sequence the V1-V3 hypervariable regions of the 16S rRNA gene and to measure pro-inflammatory [interlukin-6 (IL-6)] and anti-inflammatory [IL-10 and transforming growth factor-beta (TGFβ)] cytokine concentrations using validated commercial ELISAs. Concentration data were analyzed using repeated measures in PROC MIXED of SAS and correlations were performed in SAS using Pearson correlation. There were no differences in cytokine concentrations by day or status x day. There were no differences in uterine IL-6 or IL-10 concentrations (P > 0.05). Uterine TGFβ concentrations were overall elevated in pregnant cows compared to open cows (72.6 vs. 13.7 ± 12.1 pg/mL, respectively; P < 0.05). On d -2, a positive correlation exists between TGFβ and the relative abundance of Actinobacteria in the uterus of pregnant cows (r=0.93, P = 0.02). There were no differences in vaginal IL-6 or TGFβ concentrations (P > 0.05). On d -2, vaginal IL-10 concentrations were elevated in open cows compared to pregnant cows (741.6 vs. 602.1 ± 47.0 pg/mL, respectively; P < 0.05) and a positive correlation exists between IL-10 and the relative abundance of Lentisphaerae in the vagina of pregnant cows (r=0.89, P = 0.04). These data suggest a possible relationship between bacterial communities and cytokines concentrations within the reproductive tract of beef cattle which may affect fertility.
136 Quantitative and qualitative analysis of interferon stimulated genesMX2, OAS1, and ISG15 for detection of pregnancy in cattle
Authors: DeCarlo Andrea N , Parrish Joseph , Long Nathan , Pratt Scott
Published: November 2020

Pregnancy in cattle can be determined using transrectal ultrasonography or by detection of pregnancy associated glycoproteins present in maternal circulation begging at approximately d 28 of gestation; however, the majority of pregnancy loss occurs prior to this date. Interferon stimulated genes (ISG) have been observed to be upregulated in pregnant cattle and measurable at d 18 of gestation. The objective of this study was to assess ISG expression as an indicator of pregnancy at d 18 post-insemination. A 7-d Co Synch and CIDR estrous synchronization protocol was utilized on cows of varying age and parity (n = 80) and insemination to a single sire performed 60 to 66 h following removal of the CIDR. On d 0 and d 18 post-insemination, blood was collected via jugular venipuncture for isolation of total RNA by PAXgene Blood RNA kit (PreAnalytiX, Hombrechtikon, Switzerland). Pregnancy detection was performed on d 30 of gestation by transrectal ultrasonography. Differences in ISG expression between d 0 and d 18 samples in both pregnant (n = 10) and open (n = 10) cows, according to d 30 ultrasound, were assessed. Primers for ISGs (MX2, OAS1, and ISG15) and housekeeping, cyclophilin were generated for use in end-point PCR and qRT-PCR. Data for qRT-PCR were normalized to cyclophilin expression. Analysis of variance and pair-wise student’s t-test among LSMeans were performed with fixed effects for pregnancy status, day, and their interactions. End-point products in all ISGs, regardless of day or pregnancy status, were observed. Expression of MX2 and ISG15 were upregulated in open cows and in d 0 samples (P < 0.05). Expression of OAS1 was increased in open cows (P = 0.001). These data disagree with previous findings in which ISGs were upregulated in pregnant animals, and indicate expression of these ISGs may not be good indicators for pregnancy.
47 Effect of Zelnate administered at initial processing in high-risk, newly received beef calves on performance and morbidity
Authors: Martin Brady E , Cauble Reagan N , Kegley Elizabeth , Powell Jermey G
Published: November 2020

The objective of this study was to investigate the effects of Zelnate, a DNA immunostimulant, administered to calves (n = 261; BW 253 ± 4.0 kg) upon arrival, on morbidity and mortality, growth performance, and producer costs. Crossbred male beef calves (steers and bulls) were acquired from multiple auction markets and transported to the University of Arkansas stocker unit for a 42-d backgrounding period. Calves were randomly allocated to chute side into treatment groups: 1) Control (CON) in which no immunostimulant was administered or 2) Zelnate (ZEL), DNA immunostimulant administered. Animals were checked daily for signs of morbidity and treated with preplanned antibiotics. Records for morbidity and mortality were kept in addition to body temperature, clinical score, and body weight at the time of treatment. Data were analyzed using the GLIMMIX procedures of SAS. Significance was declared at P < 0.05 and tendencies were observed between 0.05 ≤ P < 0.10. No animals died during the duration of this study; however, Zelnate treated calves tended (P = 0.09) to have a lower relapse rate compared to control calves. Average daily gain was similar (P = 0.60) between the two treatment groups. This study also indicated that the treatment cost (Zelnate plus antibiotics) for the Zelnate group was more expensive than the cost to treat the control group (P < 0.01). Overall, our findings indicate that Zelnate administered upon arrival to high risk calves did not improve morbidity rates and respiratory treatment or affect performance; however, it did increase costs by $9.24 per calf. Based upon these results, Zelnate does not appear to be an effective therapy for BRD when given upon arrival.
169 The effects of once or twice daily feed delivery on the finishing performance and carcass characteristics of feedlot steers
Authors: Wilson Blake K , Ryan Will , Richards Chris
Published: November 2020

Yearling Angus steers (n = 64; arrival BW = 322 ± 44 kg) from a single ranch were used to determine the effects of delivering feed once (1X) or twice (2X) per day on finishing performance and carcass characteristics. Steers were blocked by BW and randomly assigned to pens (4.57 × 15.24 m; 4 steers per pen). Pens were randomly assigned to 1 of the 2 experimental treatments (1X or 2X). All steers were fed a common dry-rolled corn finishing ration for 141 d. Feed was delivered to steers in fence-line concrete bunks (4.57 m in length; 1.14 m per steer) with the only difference between experimental treatments being the frequency of feed delivery. The 1X steers received 100% of the daily feed call at 0930 h, while the 2X steers received 50% of the daily feed call at both 0930 and 1400 h. Pen served as the experimental unit, and all steers were harvested on d 142. There were no differences in final BW (P = 0.95) or overall ADG (P = 0.94) between experimental treatments; however, overall DMI was greater for the 1X steers (P < 0.01). The difference in DMI combined with no difference in ADG resulted in a 4% improvement in overall G:F for the 2X steers (P = 0.03). There were no differences between the experimental treatments for any carcass characteristics (P ≥ 0.28). While this experiment was conducted in a small pen research setting, the results suggest that the frequency of feed delivery impacts the intake and feed efficiency of feedlot steers. Consideration should be given to the impacts of feed delivery on feedlot logistics and batching in commercial settings.
32 Determining the feeding value of corn gluten feed relative to corn when supplemented to beef calves grazed on stockpiled tall fescue pastures
Authors: Zumbaugh Charles A , Murray Adam R , Langford Taylor A , Claire Olivia M , Wilson Thomas B
Published: November 2020

This experiment compared the performance response of supplementing corn gluten feed (CGF) or corn to calves grazing stockpiled tall fescue pastures over a 70-d period. Forty-four Angus x Simmental calves (238 ± 4 kg) were stratified across 6 treatments by BW and sex in a 2 x 3 factorial arrangement. Calves were supplemented cracked corn (n = 16) or CGF (n = 18). Calves were housed in 2 pastures and supplemented individually using the SmartFeed Pro feeding system, with all treatments represented in each pasture. Supplement DMI was programmed at 0.59, 0.87, or 1.13% BW. Calves which failed to train to the feeding system (n = 10) were treated as an un-supplemented control. Weight and flesh condition score (FCS) were recorded every 14-d, and ultrasound 12th rib fat thickness (FT) was measured on d 0 and 70. Data were analyzed with PROC GLM in SAS with supplement type as a main effect, sex as a fixed effect, and group as a random effect. Individual supplement DMI was included in the model as a covariate rather than a main effect due to high variation. Significance was defined at P ≤ 0.05 and means were separated using LSD. Initial BW, FCS, and FT were similar (P ≥ 0.12) among treatments. No differences (P ≥ 0.25) were observed in supplement DMI throughout the experiment. No differences (P ≥ 0.64) were observed in ADG and supplement G:F through 14 d. Through d 28 to 70, CGF-fed calves had greater (P ≤ 0.03) ADG and supplement G:F relative to corn-fed calves. Final FCS was greater (P < 0.01) for CGF-supplemented calves relative to those supplemented corn, though FT was not different (P = 0.87). These data indicate that supplementing CGF rather than corn yields a greater performance response in beef calves grazing stockpiled tall fescue.
9 Backgrounding system diet effects on performance of beef calves during transportation and feedyard adaptation
Authors: Tigue Daniel A , Rehm John G , Kerklin Alisha , Rodning Soren P , Mullenix Mary K , Bratcher Christy L
Published: November 2020

Nutritional management during the backgrounding phase may influence beef calf performance and ease-of-transition into the feedyard. The objective of this study was to evaluate effects of various diets on performance of calves during backgrounding, transportation, and arrival at a feedyard. In June 2019, 119 fall-born steers (n = 79, 266 ± 34 kg BW) and heifers (n = 40, 236 ± 26 kg BW) at E.V. Smith Research Center (Shorter, AL) were weaned and randomly assigned to one of four diets (3 pens per dietary treatment, 10 calves per pen): cool-season baleage (oats, annual ryegrass, and crimson clover; B), cool-season baleage and 1% BW of a commercial, high-energy grower supplement (BC), cool-season baleage and 1% BW dried distiller’s grains with solubles (DDGS; BD), or ‘Tifton 85’ bermudagrass hay and 1% BW DDGS (HD). After a 10-d acclimation period, calves began a 60-d backgrounding trial and were weighed at d 0, d 30, and d 60. There was a diet × period interaction (P = 0.0017) such that ADG decreased from 0.38 to 0.19 kg/d for calves on B, while in treatments with supplementation, calves maintained gains of 0.67 kg/d or greater into the second, 30-d period. After the end of the backgrounding trial, calves were transported to Hy-Plains Feedyard in Montezuma, KS. Calves were weighed prior to transport, immediately after transport, after 24 h rest, and 7 d on feed. Immediately after tranport, B calves had the greatest shrink (12.8%, P < 0.001) compared to calves that had received supplemental feed (10.1%). After 7 d, B calves regained the lowest percentage of pre-shipping BW (93.5% weight, P < 0.01) compared to calves that had received supplemental feed (96.3% weight). These data suggest that supplementing forage-based diets may provide a performance advantage during the preconditioning phase and better prepare calves for transportation and the transition into the feedyard.
82 Evaluation of feeding immunoglobulin-Y to Holstein feeder cattle for the control of liver abscesses & reduction of macrolide-resistant bacteria dissemination
Authors: Stotz Miranda K
Published: November 2020

Despite the regular use of macrolide-antibiotics in the diets of feedlot cattle, liver abscesses persist representing a financial burden to both pre- and post-mortem sectors of the beef industry. Alternative strategies, which simultaneously address liver infections and reduce the dissemination of antibiotic-resistant bacteria, are needed. An immunoglobulin-Y (IGY) product, developed to target Fusobacterium necrophorum and Trueperella pyogenes, was evaluated for the control of liver abscesses and its effect on macrolide-resistant Enterococcus growth from feces. Sixty-four Holstein steers (Initial BW= 384±13.5kg) consuming a finishing diet (90% concentrate) for 188 days (Final BW= 660±42 kg) were used in a completely randomized design where treatments included: TYL (Tylosin phosphate fed at 90 mg/hd/day; n = 32) or IGY (fed at 2.5g/hd/day; n = 32).Feed intake was recorded daily and BW was recorded every 28 days until slaughter. After 150 d on treatment fecal samples were randomly obtained from each treatment group four times (n = 40) and cultured on bile-esculine agar enriched with 8 μg/mL of erythromycin. Continuous variables of feedlot growth performance, carcass data and bacterial growth were analyzed using the MIXED procedure of SAS with the fixed effect of treatment and random effects of steer or sampling day, respectively. Ordinal carcass data was analyzed using the FREQ procedure of SAS observing the Cochran-Mantel-Haenszel value. Treatment did not affect DMI (P = 0.21), ADG (P = 0.50) or G:F (P = 0.36). Treatment neither affected hot carcass weight (P = 0.37) nor longissimus muscle area (P = 0.25). However, TYL resulted in greater back fat thickness than IGY (0.32 vs. 0.23 in.; P < 0.02) and consequently greater numerical yield grade (P < 0.02). Quality grade was not affected by treatment (P = 0.65). No treatment difference was observed for liver abscesses prevalence (TYL= 63% vs. IGY= 52%; P = 0.40) or severity (P = 0.23). There was a greater proportion of erythromycin-resistant Enterococcus growth for TYL than IGY (42.6 vs. 21.9%; P < 0.04). Specifically formulated IGY feed additives may be viable alternatives to antibiotics in the diets of feedlot cattle.
152 The Effect of Nerve Growth Factor Beta on Embryonic Cleavage Rates
Authors: Jones Kayla
Published: November 2020

Nerve growth factor, (NGF) beta is a seminal plasma protein that has been associated with sire conception rates in cattle. Previous research showed that the administration of NGFβ, via culture media, to cows resulted in improved conceptus development. Though this finding was thought to be an indirect effect of improved corpus luteum (CL) function, questions raised if NGFβ could act directly on the embryo to promote development. This work seeks to determine the effect of NGFβ supplementation during in-vitro fertilization (IVF) on cleavage and blastocyst rates. How does the administration of NGFβ in culture media affect cleavage and blastocyst rates during in-vitro fertilization? Abattoir-derived bovine ovaries were used for recovery of cumulus-oocyte complexes (COC). Selected COC were placed in the maturation medium. Expanded COC were inseminated with frozen-thawed spermatozoa, and IVF media was supplemented with either 0 ng/mL or 100 ng/mL NGF. Presumptive zygotes were transferred to development medium in a tri-gas chamber with 5% CO2, 5% O2, and 90% N2 in a humidified atmosphere at 39°C, mimicking the bovine uterine climate, until 8 days. Treatment with NGFβ increased the percentage of cleaved embryos at 48 hours and the percentage of hatched embryos at 8 days per oocyte. Treatment of NGFβ did not alter the percentage of blastocysts per cleaved embryo or the percentage of hatched blastocysts. These results show that the NGFβ can act directly on the embryo during fertilization to alter embryonic development, specifically embryonic cleavage rates. Future in vivo studies should assess the downstream effects of NGF treatment on conception rates in cattle.
144 Rumen Fluid Metabolites as Potential Biomarkers of Feed Efficiency in Angus Steers
Authors: Clemmons Brooke A , Powers Joshua B , Campagna Shawn R , Ault Taylor B , Embree Mallory M , Myer Phillip R
Published: November 2020

Beef cattle is the most consumed red meat in the United States, and the United States is the largest producer and consumer of beef cattle globally. Feed is one of the largest input costs for the beef cattle industry, accounting for 40–60% of the total input costs. Identifying methods for improving feed efficiency in beef cattle herds could result in decreased cost to both producers and consumers, as well as increased animal protein available for global consumption. Identification of feed efficiency biomarkers could aid in the selection of more feed-efficient animals. To identify potential biomarkers of feed efficiency, rumen fluid was collected from low- (n = 14) and high-RFI (n = 15) Angus steers based on RFI ± 0.5 SD around the mean following a 70d feed efficiency trial to determine rumen metabolites associated with variations in feed efficiency. Steers were 7 months of age, weighing 264±2.7 kg. Rumen fluid was collected via gastric tubing, filtered through a 0.22 µM syringe filter, extracted for metabolomic analysis using 0.1% formic acid in acetonitrile:water:methanol (2:2:1), and injected into the Dionex UltiMate 3000 UHPLC system with an Exactive Plus Orbitrap MS. Peaks for known metabolites were identified using MAVEN and analyzed using MetaboAnalyst 4.0 and SAS. Significance was determined using an α ≤ 0.05. Based on fold change (high/low RFI), eight metabolites were greater in low-RFI steers compared to high-RFI steers, including 3,4-dihydroxyphenylacetate, 4-pyridoxate, citraconate, hypoxanthine, succinate/methylmalonate, thymine, uracil, and xylose (P ≤ 0.05), while 12 metabolites differed by ≥ 2-fold. These metabolites were predominantly involved in amino acid and lipid metabolism. Rumen fluid metabolomes differed in steers of varying feed efficiencies. These metabolites may be used as biomarkers of feed efficiency and may provide insight as to factors contributing to differences in feed efficiency that may be exploited to improve feed efficiency in beef cattle herds.
123 Polyclonal antibody preparations from avian origin did not reduce plasmatic haptoglobin concentrations but increased ruminal NH3-N in beef steers during transition from forage to high-grain diets
Authors: da Silva Gleise Medeiros , Podversich Federico , Schulmeister Tessa M , Santos Erick Rodrigo Silva , Sanford Carla , Siqueira Michelle C B , Tarnonsky Federico , DiLorenzo Nicolas
Published: November 2020

This study investigated the effects of feeding an avian-derived polyclonal antibody preparation (PAP; CAMAS, Inc.) against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides (40, 35, and 25% of the preparation, respectively) on plasmatic haptoglobin, ruminal short chain fatty acids (SCFA), and ammonia-N (NH3-N) concentrations of beef steers during a 21-d step-up adaptation to a high-grain diet. Eight ruminally cannulated Angus crossbred beef steers (658 ± 79 kg BW) were randomly assigned to treatments in a crossover design to be transitioned from a diet containing bermudagrass hay [Cynodon dactylon (L.) Pers.] plus 0.45 kg/d of molasses with 0 (CON) or 3 g/d of PAP (PAP) to a high-grain diet. Transition consisted of three 7-d steps of increased inclusion of cracked corn (35, 60, and 80% diet DM for STEP1, STEP2, and STEP3, respectively). On each transition d and 7 d after STEP3 (STEP3-7d), ruminal fluid samples were obtained every 3 h for 24 h. Blood samples were collected on d 0, 1, and 3 relative to each transition for haptoglobin determinations. Haptoglobin plasmatic concentrations increased (P = 0.03) on d 2 and 3 vs. d 1 during STEP2 and on STEP3 compared to STEP1 and STEP2 (P = 0.01). Steers receiving PAP had greater (P < 0.01) ruminal NH3-N concentration in STEP1; however, there were no effects of treatment on SCFA (P > 0.10). Total SCFA concentrations were affected by the step-up diets (P < 0.01); propionate concentration (Pro) was greater in STEP2 through STEP3-7d vs. STEP1 (P < 0.01), whereas acetate concentration (Ac) and Ac:Pro linearly decreased from STEP1 to STEP3-7d (P < 0.01). Feeding 3 g/d of polyclonal antibody preparations against Streptococcus bovis, Fusobacterium necrophorum, and lipopolysaccharides in a 21-d step-up adaptation to high-grain diets did not affect plasmatic haptoglobin or ruminal SCFA concentrations; however, it increased ruminal NH3-3 concentrations.
1 A survey of anthelmintic resistance in Angus bulls participating in centralized performance tests in Appalachia
Authors: Rohrbaugh Roger T , Weaver Andrew R , Greiner Scott P , Bowdridge Scott A
Published: November 2020

Parasitism in weaned calves and anthelmintic resistance can negatively impact performance and reduce profitability. To better understand anthelmintic resistance, bulls were evaluated for fecal egg count (FEC) at performance test facilities in Virginia and West Virginia. Over a two-year period, 532 Angus bull calves were tested at bull development facilities in Wardensville, WV (n = 274), Culpeper, VA (n = 167), and Wytheville, VA (n = 91). Fecal samples were collected upon arrival and 14 d later, representing the warm-up or transition period. At arrival, bulls were treated with either albendazole (Wardensville) or moxidectin (both VA tests). Data were analyzed via the general linear model of SAS with fixed effects of station and year. Correlation analysis of arrival FEC and transition ADG was analyzed using the correlation procedure in SAS. The average FEC reduction (FECR) in bulls at Wardensville was 98%; whereas, FECR at Culpeper and Wytheville was 46% and 16% respectively. Average FEC of bulls at Wytheville, Culpeper and Wardensville were different (P < 0.05) after treatment and had a FEC of 133, 51, 3 eggs/g, respectively. Transition ADG favored bulls from Wardensville and Culpeper (2.43 and 2.31 kg/d; P > 0.05) where bulls at Wytheville had lower ADG compared to either station (1.03 kg/d; P < 0.01). Correlation between arrival FEC and transition ADG was negative for bulls in Wardensville (-0.22; P = 0.0003). This same response was not observed at other stations. Lack of a correlation was most likely due to infection level being so low that abundant feed resources masked effects of parasitism, or parasitism was so great that all cattle transitioned poorly. Nonetheless, these data clearly demonstrate the efficacy of albendazole in significantly reducing fecal egg output in bull calves and identify potential resistance to moxidectin.
105 Impacts of Phosphorus Intake on Beef Heifer Growth Performance and Reproductive Tract Scores
Authors: Hilfiker Hailey , Kegley Elizabeth , Rorie Rick , Hornsby Pete A , Reynolds Jana , Shoulders Ben P , Cauble Reagan N , Powell Jermey G
Published: November 2020

This study aims to examine the effects of phosphorus intake on beef heifer growth performance and conception rates. In Northwest Arkansas, there has been an increase in phosphorus concentrations in soil where livestock manures have been repeatedly applied. Consequently, forages grown on soils high in phosphorus tend to contain high amounts of the mineral itself. This has led many to question whether it is necessary to supplement phosphorus in areas where concentrations may be higher. In this study, crossbred Angus heifers (n = 72), approximately 30 d after weaning, were stratified by body weight (average initial weight 251 ± 3.9 kg) and allocated randomly into 8 groups. Groups were assigned randomly to 1 of 2 treatments. Treatments were delivered through either 1) a free-choice-mineral mix that contained no supplemental phosphorus (CON), or 2) a free-choice-mineral mix with 4% supplemental phosphorus and identical concentrations of other supplemental minerals (4PMIN). Heifers grazed 2.42 ha mixed grass pastures with a history of livestock manure application and were supplemented with soy hulls (0.5% of body weight) daily. Data were analyzed using the mixed procedures of SAS with group as the experimental unit. Total mineral intake through d 112 did not differ (P = 0.55) between treatments. On d 112, any heifers > 273 kg body weight (n = 58) had an ultrasound evaluation of their reproductive tract. Reproductive tract score (1, infantile to 5, corpus luteum present) did not differ (P = 0.65) due to treatment. Body weights were not different (P = 0.78) on d 112, 301 ± 5.0 kg and 299 ± 5.0 kg for CON and 4PMIN, respectively. When grazing pastures with a history of livestock manure application, levels of supplemental phosphorus in the free choice mineral did not affect heifer growth performance and reproductive tract scores.
55 Effects of concentrate supplementation frequency and amount on growth and reproductive performance of Brangus heifers
Authors: Palmer Elizabeth , Vedovatto Marcelo , Ranches Juliana , Oliveira Rhaiza , Arthington John , Vendramini Joao , Moriel Philipe
Published: November 2020

A 2-yr study evaluated the impacts of supplementation frequency and amount on growth and puberty attainment of Brangus heifers. On d 0 of each year, 64 Brangus heifers were stratified by BW and age (244 ± 4 kg; 311 ± 18 d) and assigned to 1 of 16 bahiagrass pastures (4 heifers/pasture). Treatments were randomly assigned to pasture (4 pastures/treatment) in a 2 × 2 factorial design and consisted of heifers offered a soybean hulls-based supplement DM at 1.25% or 1.75% of BW delivered either daily (7X) or 3 times weekly (3X; Monday, Wednesday, and Friday). On d 56, heifers were inserted with a CIDR device for 14 d, followed by administration of PGF2α and a timed-AI+GnRH protocol on d 89. Heifers were exposed to bulls from d 89 to 167. Data were analyzed using the SAS GLIMMIX procedure. No rate × frequency interactions were detected (P ≥ 0.20). Overall ADG was greater for 7X vs. 3X heifers (P = 0.007). Daily supplementation increased (P ≤ 0.03) the percentage of pubertal heifers prior to CIDR insertion and at AI compared to 3X supplementation; however, percentage of pregnant heifers did not differ (P = 0.70). Supplementation at 1.25% vs. 1.75% enhanced the overall ADG (P = 0.02) but did not impact (P = 0.18) the percentage of pubertal heifers before CIDR insertion. After the puberty induction protocol, heifers supplemented at 1.75% of BW achieved greater puberty attainment at time of AI (P = 0.05) and final pregnancy rates (P = 0.02) than heifers supplemented at 1.25% of BW. When a puberty induction protocol was included, the percentage of pregnant Brangus heifers were not affected by supplementation frequency (daily vs. 3 times weekly) but enhanced when the supplement dry matter amount was offered at 1.75 vs. 1.25% of body weight.
126 Pre- and post-partum supplementation of molasses/urea, with or without methionine fortification, to enhance growth and physiology of Bos indicus-influenced primiparous cows and their offspring
Authors: Palmer Elizabeth , Vedovatto Marcelo , Ranches Juliana , Gouvea Vinicius , Oliveira Rhaiza , Arthington John , Vendramini Joao , Moriel Philipe
Published: November 2020

A 2-yr study evaluated the effects of molasses/urea supplementation during pre- and early postpartum, with or without methionine fortification, on growth and physiology of primiparous cows and their offspring. On d 0 of each yr, 36 cows were stratified by BW and BCS (396 ± 54 kg; 5.67 ± 0.66) and randomly assigned to 1 of 12 bahiagrass pastures (3 cows and 1.2 ha/pasture). Treatments were randomly assigned to pastures (4 pastures/treatment) and consisted of no supplementation (NOSUP), 1 kg/d of molasses/urea (MOL; DM basis), or 1 kg/d of MOL + 18 g/d of methionine hydroxy analog (MOLMET; Alimet, Novus, St. Charles, MO). Supplementation began 56 d before parturition (d 0) and ended when all cows within each pasture had calved (d 74). Calves were early weaned on d 147. On d 154, 24 calves (8 calves/treatment) were transferred to individual drylot pens, and offered ad libitum stargrass hay plus soybean hulls-based concentrate DM (75% TDN; 22% CP) at 3% of BW for 47 d. On d 160, calves were vaccinated against bovine viral diarrhea virus-1 (BVDV-1) and parainfluenza-3 (PI-3). Data were analyzed using the MIXED procedures of SAS. Cow BCS at calving was greater (P ≤ 0.05) for MOL and MOLMET vs. NOSUP but the overall percentage of pregnant cows did not differ among treatments (P = 0.82). Calf ADG from birth to drylot exit did not differ (P = 0.83) between MOL and MOLMET but was least (P ≤ 0.04) for NOSUPP calves. Seroconversion to BVDV-1 and PI-3 viruses were greater (P ≤ 0.05) for MOL and MOLMET vs. NOSUP calves. Hence, cow supplementation of molasses/urea during pre- and early postpartum improved cow prepartum BCS, and calf growth and humoral immunity. Methionine fortification of supplements did not impact cow and calf performance.
71 Effects of timing of supplementation during late gestation in Bos indicus-influenced beef cows on post-weaning growth, immunity, and carcass characteristics of steer progeny
Authors: Palmer Elizabeth , Vedovatto Marcelo , Ranches Juliana , Gouvea Vinicius , Oliveira Rhaiza , Arthington John , Vendramini Joao , Poore Matt H , Moriel Philipe
Published: November 2020

This study evaluated the growth, immunity, and carcass characteristics of beef steers born to cows offered dried distillers grains (DDG) at different timing during late gestation. Approximately 84 d before calving (d 0), 84 mature Brangus cows were stratified by BW and BCS (422 ± 42 kg; 5.0 ± 0.14) and allocated into 1 of 6 bahiagrass pastures (14 cows/pasture). Treatments were randomly assigned to pastures: 1) no prepartum supplementation (CON); 2) 1 kg/d DDG from d 0 to 84 (LATE84); or 3) 2 kg/d from d 0 to 42 (LATE42). Calves were weaned at 261 ± 23 d of age. At weaning, 38 steers were vaccinated against bovine viral diarrhea virus (BVDV-1) and parainfluenza-3 (PI-3) and transported to a feedlot facility. Steers were penned according to cow prepartum pasture distribution and fed a similar diet until slaughter (d 587). Data were analyzed as complete randomized design using MIXED procedure of SAS, pasture as the experimental unit, treatment as fixed effect, and pasture(treatment) and steer(pasture) as random effects. Steer feedlot BW, ADG, DMI, and G:F did not differ (P ≥ 0.12) among treatments. Plasma haptoglobin concentrations were greater (P ≤ 0.03) for LATE42 and LATE84 vs. CON steers 2 d after feedlot entry. Plasma cortisol and seroconversion for BVDV-1 and PI-3 did not differ (P ≥ 0.15) among treatments. The percentage of carcasses grading Choice did not differ (P = 0.13), but carcasses grading low Choice were greater (P = 0.03) for CON vs. LATE42, with LATE84 being intermediate (91, 40, and 58%, respectively). Thus, prepartum dried distillers grain supplementation to B. indicus-influenced cows did not enhance feedlot growth but had subtle positive impacts on carcass quality and innate immunity in steer progeny. In addition, timing of dried distillers grain supplementation (last 84 d vs. first 42 d of late gestation) did not impact steer post-weaning feedlot performance and carcass quality.
40 Effect of calving season in an artificial insemination program on finishing performance and carcass traits
Authors: Garcia Taylor J , Robison Colton A , Beck Paul A , Reuter Ryan R , Wilson Blake K , Lalman David L
Published: November 2020

Spring (SPRING) and fall (FALL) born steers (n = 211) were used in a mixed effects model to evaluate calving season and conception method [artificial insemination (AI) or natural service (NS)] on finishing performance and carcass traits. SPRING were weaned in October, grazed dormant range for 90 days and grazed wheat pasture for 90 days before shipping to finish. FALL were weaned in May, and grazed tallgrass prairie for 120 days before shipping to finish. Initial and final BW, days on feed, ADG, DMI, and gain to feed efficiency were evaluated as performance measures. Dry matter intake and gain:feed were analyzed on pen basis. Hot carcass weight, yield grade, fat thickness, ribeye area, and marbling score were collected at harvest. Bodyweight of SPRING and AI steers were heavier (P ≤ 0.05) entering and leaving the feedlot than FALL and NS steers, respectively. Compared to FALL steers, ADG (P < 0.01) and DMI (P = 0.03) were greater for SPRING and required less days on feed (P ≤ 0.05). Calving season and conception method (P ≥ 0.2) did not affect gain:feed. Conception method (P = 0.5) did not affect ADG, DMI, and days on feed. SPRING had higher yield grades (P < 0.01) and increased in fat thickness (P = 0.01) compared to FALL steers. There were no differences (P = 0.2) in hot carcass weight, ribeye area, and marbling score due to season of birth. Steers born from AI mating had greater hot carcass weight (P = 0.01) and marbling score (P = 0.02), but conception method did not affect yield grade, fat thickness, and ribeye area (P > 0.2). These results demonstrate SPRING steers are heavier entering and leaving the feedlot, have higher ADG and DMI, and require less days on feed; however, gain:feed, hot carcass weight, ribeye area, and marbling score did not differ from FALL steers. An economic analysis is needed to validate an AI program based on calving season in north-central Oklahoma.
155 The effect of number of cattle per pen on stocker cattle health and performance
Authors: Midkiff Kirsten A , Karisch Brandi , Woolums Amelia
Published: November 2020

The objectives of this study were to: 1) to examine the effect of number of stocker cattle in a receiving pen on BRD morbidity and mortality; and 2) to examine the effect of number of stocker cattle in a receiving pen on cattle performance. Crossbred steers of unknown origin and history (n = 200) were purchased from auction barns in the southern portion of the United States. Cattle were stratified by weight and assigned to either a small (10 head/pen) or large (50 head/pen) treatment on arrival. Calves were assigned to 1 of 3 large pens or 1 of 5 small pens. Cattle were observed daily for clinical signs of BRD and treated if rectal temperature ≥40°C. Body weight was collected on d 0, 14, 28, 42, and 56. Rectal temperature was collected at arrival. Days-at-risk for BRD was the number of days from arrival until a calf: (1) was first diagnosed with BRD; (2) died; or (3) finished the trial. Treatment effects on BRD incidence and performance were tested using Poisson distribution and logistic regression using GLIMMIX or linear regression using MIXED procedure of SAS, respectively, accounting for clustering by pen. Mortality was analyzed using the LOGISTIC function with Firth’s penalized likelihood. There were 8,698 total days at risk and overall incidence density was 7.82 BRD cases per 1,000 calf days. Overall morbidity totaled 32.5% with 5.5% mortality. No difference among treatment was observed for morbidity, mortality, or performance. Cattle with fever on arrival were 1.125 times more likely to contract BRD (P ˂ .0001). The number of BRD treatments received had an effect on ADG at d 0–14 (P ˂ .0001), 0–28 (P ˂ .0001), and 0–60 (P ˂ .0001), with ADG decreasing as number of treatments increased. In summary, fever on arrival affected BRD incidence, and number of treatments cattle received affected growth throughout the trial.
94 Impact of a Hydrolyzed Yeast Product on Performance, Hair Coat Shedding, and Behavior of Cows Grazing Pastures Containing Endophyte-Infected Tall Fescue
Authors: Harrelson Patricia L , Martin Rick , Rogers Brent , Harrelson Flint W
Published: November 2020

Endophyte-infected tall fescue creates a multitude of problems for many beef producers, with supplementation being one management strategy to decrease these problems. Our research objective was to determine if supplementation with a hydrolyzed yeast product could alleviate some symptoms of fescue toxicosis in mature cows. Across the 3-yr study, Angus cow-calf pairs (n = 34, 38, 34) were stratified by cow age and body weight then randomly allotted to one of two treatments; control mineral (CON) or hydrolyzed yeast mineral (HYM). Cattle in both treatment groups grazed the same mixed grass pastures (n = 6, 8, 8; 1.21 ha each) which contained varying levels of endophyte (20 – 90%) as measured prior to each year, in a rotational pattern for 126, 133, or 140 d, depending upon year. Prior to entering a new pasture weekly, cows were weighed and assigned a BCS and hair coat score (HC) by two independent, trained personnel. Cow behavior was measured every 15-min within a 2-h block weekly. Percentage of cows active or inactive, outside or inside a barn was recorded. Data were analyzed using the MIXED procedure of SAS. Cow BW change was affected (P < 0.01) by a treatment×year interaction. Cow BCS increased in HYM vs. CON cows (0.34 vs. 0.06; P < 0.01; SEM = 0.08) across the entire trial. Cows consuming the HYM supplement also spent a greater percentage of time outside being active (P < 0.01) and a lower percentage of time inside being inactive (P < 0.01) compared to CON cows. Results from this trial indicate that the hydrolyzed yeast mineral may be an effective tool to aid in combating heat stress associated with fescue toxicosis.
98 Impact of social mixing on feedlot steer eating and lying behavior
Authors: Hubbard Amanda J , Sawyer Jason , Cooke Reinaldo F , Jennings Jenny , Daigle Courtney L
Published: November 2020

This study evaluated the impact of mixing cattle from two sources of feedlot steers (n = 96) on feeding and lying behavior. Angus crossbred steers (n = 48 McG and n = 48 BCS), similar in genetic composition, were transported (833.64 ± 85.29 km) to a feedlot 39-d prior to mixing where the two sources were housed without visual or tactile contact. Steers, blocked by source and stratified by d -34 body weight, were randomly assigned to one of 12 pens (n = 8 steers/pen) for the 42-d study. Pens were assigned to one of two treatments (n = 6 pens/treatment): 1) NOMIX—100% of cattle from McG (n = 3 pens) or BCS (n = 3 pens) and, 2) MIX—50% of cattle from BCS and 50% from McG (n = 6 pens). Instantaneous scan sampling (n = 61 scans/d; 10 min intervals) recorded the number of steers per pen eating and lying on d1, 2, 3, 4, 5, 6, 7, 8, 9, 14, 15, 16, 21, 22, 23, 28, 29, 36, and 37 after mixing. Proportion of steers lying varied across time (P < 0.0001); however, a greater proportion of steers laid down on d1 compared to d7, 8, 9, 16, and 28 (P < 0.03). The proportion of steers observed eating increased over time (P < 0.0001). Fewer steers ate on d1 than d9, 14, 15, 28, 29, and 36 (all P < 0.01). More steers were observed eating on d8 and 16 than the first seven days (all P < 0.01) and on d37 than the first 6 days (all P < 0.02). While there was no impact of mixing, data indicate that handling and sorting cattle into new pens impacts eating and lying behavior and it takes approximately a week for behavior to stabilize.
67 Effects of Maternal Disposition and Calf Chute Behavior at Weaning on Calf Finishing Performance
Authors: Sims Michael , Beck Paul A , Stewart Cyril B , Shelton Cody , Cauble Reagan N , Warner Andrea L
Published: November 2020

Temperament has been reported to impact calf performance. The purpose of this study was to investigate the relationship between maternity disposition and calf temperament at weaning to finishing performance. Maternal disposition at calving and calf chute behavior at weaning data were collected from the University of Arkansas between August 2017 and May 2018. Calves were finished at Oklahoma State University Willard Sparks Research Center between October 2018 and August 2019. Cow behavior was observed at calving and received a disposition score (CDS) that used a 5-point scale where a score of 1 was highly aggressive, and a 5 was apathetic. At weaning, calf weight (WW) and chute behavior (CS) was recorded. Chute behavior at weaning used a 5-point scale; a score of 1 was indicative of a calm exit, and a 5 was aggressive when exiting the chute. Data were analyzed using the GLIMMIX procedure of SAS. Significance was declared at P ≤ 0.05. Calves with CS of 2 at weaning had greater BW both on arrival to feed yard (P < 0.01) and at harvest (P = 0.01) than calves with a CS of 3. Calves from cows with CDS of 3 had greater feedlot arrival weights (P = 0.01) and ADG (P = 0.01) than calves from cows with CDS of 4. This study indicates that cattle with nervous chute behavior (CS = 3) had potentially detrimental effects on performance and can impact overall life-time productivity.