bluuebunny/crossref_metadata_2025 huggingface dataset:
32 Depot-Specific Transcriptome and Adipocyte Metabolism in Intramuscular and Subcutaneous Adipose Tissue in Beef Cattle
Authors: Tegeler Alexandra P , Fiallo-Diez Jean , Michelotti Tainara , Flores Lauryn , Benitez Oscar J , Johnson Bradley J , Strieder-Barboza Clarissa
Published: May 2023

Intramuscular adipose tissue (IMAT; marbling) deposition is the primary determination of beef quality grade in the U.S. While finishing diets increase marbling, they also increase subcutaneous adipose tissue (SAT) accumulation, leading to excessive fattening and economic losses due to ‘waste fat’. Our objective was to investigate the IMAT and SAT-specific transcriptional profile and adipocyte function in vitro. A better understanding of the mechanisms underlying IMAT and SAT-specific characteristics will help to identify molecular and cellular molecules for developing targeted strategies to enhance marbling while limiting overall fatness in beef animals. A section of the Longissimus dorsi muscle from 9-11th ribs was collected to dissect IMAT and adjacent SAT (backfat) from six beef animals harvested at the Texas Tech University Meat Lab. The SAT and IMAT RNA was extracted and sequenced in an Illumina NovaSeq 6000 targeting a minimum of 30 million reads per sample. Transcriptome analysis showed more than 1,800 differently expressed genes (DEGs) in IMAT and SAT. There was a downregulation of genes associated with adipogenesis, lipolysis regulation, insulin sensitivity, and fatty acid metabolism (e.g., LEP, INSIG1, and PLIN4) in IMAT vs. SAT, while pathways of insulin resistance and ß-adrenergic signaling were activated. To elucidate whether the differences between IMAT and SAT transcriptional profiles were translated into changes in the adipocyte function, preadipocytes were isolated, cultured, and differentiated into adipocytes in vitro for 14 followed by functional analyses of adipogenic capacity, insulin sensitivity, and lipolytic responses. Statistical analysis was performed in GraphPad 9. Even though preadipocytes were more abundant in IMAT than in SAT (flow cytometry quantification of CD45-CD31- cell), IMAT preadipocyte proliferation rates were decreased compared with SAT. Additionally, SAT adipocytes were larger than IMAT. These findings suggest an enhancement in SAT adipogenesis/lipogenesis compared with IMAT. Metabolically, SAT adipocytes released greater glycerol concentrations compared with IMAT upon ß-adrenergic stimulation of lipolysis with isoproterenol and tended to have greater insulin-stimulated glucose uptake compared with IMAT. Altogether, these findings indicate that IMAT is unable to accumulate lipids as efficiently as SAT, and these differences may be underlined by a decreased preadipocyte hyperplasia, insulin resistance, and potential dysregulation of ß-adrenergic receptors, all of these similarly suggested by the transcriptome analysis. Our study revealed molecular and cellular differences between IMAT and SAT that may partly explain why it is common to observe increased SAT fatness and limited marbling beef cattle.
22 Influence of Cell-Mediated Immune Response Classification on Performance of Heat-Stressed Dairy Cattle
Authors: Johnston Briana P , Oliveira Mauricio X S , Becker Carly A , Welsh Thomas H , Randel Ron D , Lemley Caleb O , Stone Amanda E , Littlejohn Brittni P
Published: May 2023

The objective was to evaluate the influence of cell-mediated immune response classification on performance of dairy cattle experiencing conditions of heat stress on pasture. On d 0, pregnant, lactating dairy cows (n = 27; 18 Holstein and 9 Jersey) received a subcutaneous sensitization dose of killed Candida albicans (CA; 0.5 mg) with Quil-A adjuvant (0.75 mg) in 2.5 mL of PBS. Tail skin fold thickness (SFT) was measured with a Harpenden caliper on d 14 immediately following an intradermal injection of killed CA (0.1 mg in 0.5 mL of PBS) in the right tail skin fold and a control injection (PBS) in the left tail skin fold. On d 15, change in SFT was measured and used to assign cell-mediated immune response classifications (CMIR) as High (HR; >0.5 SD above the mean; n = 9), Intermediate (IR; within 0.5 SD above or below the mean; n = 10), or Low (LR; >0.5 SD below the mean; n = 8). Cows from each CMIR were assigned to 1 of 3 environmental conditions (EC): No Abatement (no heat abatement provided; n = 9), Shade (portable shade structure; n = 9), or Sprinklers (polyvinyl chloride sprinkler system; n = 9) for a 38-d period (July 1, 2019 to August 8, 2019). Daily Milk Yield (DMY), Reticulorumen Temperature (RT), Heat Stress Score (HSS; 0 = respiration rate of < 80 breaths/min to 4 = moribund, labored breathing), and instances of Mouth Open (MO), Tongue Out (TO), and Drool were recorded daily. Respiration rate (RR; breaths/min) was recorded 3 times/day (morning, midday, and late afternoon) and averaged on Monday, Wednesday, and Friday weekly. Body Condition Score (BCS; 1 = emaciated to 5 = obese) was recorded weekly. Data were analyzed using MIXED procedures of SAS specific for repeated measures with CMIR, EC, Breed, Time and 2-way interactions as fixed effects and Pen as random. Low exhibited the lowest HSS and BCS, but the greatest MO and TO instances (P < 0.02). High exhibited the greatest instances of Drool (P < 0.02). Heat stress score, MO, and Drool were greatest in the No Abatement group (P < 0.01). Respiration rate was greatest in the No Abatement and Shade groups relative to Sprinklers (P < 0.01). Daily milk yield, RT, and Drool were increased whereas HSS and RR were decreased in Holstein relative to Jersey cows (P < 0.01). Interactions (P < 0.05) included: CMIR by EC for DMY, HSS, RR, MO, TO, and Drool; CMIR by Breed for RT, DMY, and BCS; EC by Breed for RT, DMY, HSS, and RR; and EC by Time for DMY, HSS, BCS, RR, MO, and TO. There was an effect of Time for all variables (P < 0.05). Preliminary results suggest an influence of cell-mediated immune response classification on performance of dairy cattle experiencing conditions of heat stress and warrant future studies with an increased number of animals.
27 Bacterial Community Diversity in Fresh Extended Boar Semen
Authors: McAnally Brooke E , Smith Molly S , Wiegert Jeffrey G , Palanisamy Vignesh , Dass Sapna Chitlapilly , Poole Rebecca K
Published: May 2023

Status of bacterial diversity within the male seminal microbiome has previously been linked to fertility status in mammals. However, minimal research has focused on the reproductive microbiome in boar semen. The objective of this study was to analyze the diversity of bacterial communities within fresh extended boar semen samples 1) between studs, 2) over 5 consecutive days, and 3) between pooled and single-sire doses. Eight single-sire (n = 4 per stud) and eight pooled (n = 4 per stud) fresh extended semen doses (80 mL) were obtained from two boar studs (A vs. B). Pooled doses were the composite of boars in single-sire doses. Doses were subsampled (16 mL) for 5 days post-collection. Negative controls remained unopened until the last day. Each day, 5 mL of each subsample were flash frozen and stored at -80°C for bacterial analysis targeting the V4 hypervariable region of the 16S rRNA gene for Illumina sequencing. Quality of all sequences was determined by FastQC before being processed for taxonomic analysis using the qiime2 pipeline. Alpha diversity (difference within sample metric) was analyzed using Kruskal-Wallis test, whereas PERMANOVA was performed for beta diversity analysis (differences between sample metric). According to alpha diversity metrics, Chao1 (P < 0.01) and Shannon’s index (P < 0.01) indicated contrasts in diversity among all days and the negative controls. This was further confirmed with a pairwise comparison between individual groups, in which day 1 exhibited lower alpha diversity when compared with days 2, 3, 4, and 5 using Chao1 (P < 0.01) and Shannon’s index (P < 0.01). Interestingly, reduced diversity was observed for day 1 compared with the negative controls with Chao1 (57.4 ± 6.6 vs. 132.4 ± 22.1, P < 0.01, Q < 0.01; respectively) and Shannon’s index (4.8 ± 0.2 vs. 6.1 ± 0.3, P < 0.01, Q < 0.01; respectively). No differences between boar stud or sire-type were detected for alpha diversity metrics. For beta diversity analyses, both PCoA plots and PERMANOVA for weighted unifrac metric demonstrated no significant clustering between sampling days. However, distinctions between all days and negative controls were identified using PERMANOVA for unweighted unifrac metric. Specifically, differences were discovered between day 1 and days 3, 4, and 5 (P < 0.01, Q < 0.01). PERMANOVA for both weighted (P < 0.01) and unweighted (P < 0.01) unifrac metrics revealed distinct clustering by boar stud. However, there were no differences in beta diversity between pooled and single-sire samples for both weighted and unweighted unifrac metrics. Based on these results, bacterial diversity within a semen sample may be altered over time and could occur between boar stud operations. Additional studies analyzing the reproductive microbiome of semen could help improve the characterization of fertility status in boars.
17 Using Photobiomodulation to Improve Bovine Oocyte Maturation
Authors: Richey Kendall , Hersom Matt , Bridges William , Checura Celina M
Published: May 2023

Oocyte cytoplasmic maturation is critical in determining the success of subsequent embryo development. Bovine oocytes matured in vitro yield less embryonic development rates than in vivo matured oocytes and new strategies are needed to improve the culture system. It has been proposed that light in the red-to-near infrared optical region (~600-1000 nm) enhances cellular metabolic activity through activation of the mitochondrial respiratory chain and has the potential to modify the oocyte metabolome. The objective of this work was to affect the cumulus-oocyte-complex metabolic state using photobiomodulation, aiming to enhance cytoplasmic maturation and subsequent embryonic development. A standardized in vitro fertilization (IVF) protocol and commercial media (IVF Bioscience) were used. Briefly, bovine ovaries were obtained at a local slaughterhouse, cumulus oocyte complexes (COCs) were collected by aspiration of small (2-6 mm) follicles. Compacted COCs were cultured in in vitro maturation media (n = 50/well) and treated with no light (control); light (660-665nm) for 10 minutes at hour 16 from start of maturation (L-16), and light for 10 minutes at hour 20 from start of maturation (L-20). At hour 22 from start of maturation, COCs were fertilized by co-culture with bull spermatozoa (1x106 motile sperm/mL) for 18 hours, then subjected to cumulus cell removal. Presumptive zygotes were placed in in vitro culture media (IVC) for 48 hours when cleavage rate was assessed. Embryos with ≥ 8 cells were selected and placed in fresh IVC until evaluation of blastocyst rate at 168 and 192 hours from start of fertilization. The experiment was replicated 6 times. Blastocysts present at 168 hours from start of fertilization were fixed in 5% formalin, stained with Hoechst 33342, imaged with Cytation 1 (Agilent Technologies Inc.), and blastocyst cell number was counted using ImageJ software (ImageJ2 2.9.0) in 4 replicates. For statistical analysis, each well was considered as experimental unit in a model of repeated measures, main effects of time and treatment, blocked by replicate (Mixed procedure, SAS Institute Inc.). One-way ANOVA test was used to analyze the average cell number per well by group, blocked by replicate (JMP Pro 16.1.0). There was a significant (P < 0.05) effect of treatment, replicate, and time for embryo development and there was a tendency (P = 0.6) for treatment effect on blastocyst cell number. Cleavage rates were 81.3 ± 2.5; 88.5 ± 2.5; 87.3 ± 2.5 % (LSM ± SEM), blastocyst rates were 49.1± 2.5; 49.3 ± 2.5; 51.6 ± 2.5 % and cell numbers were 159.9 ± 3.5; 149.3 ± 3.5; 164.0 ±3.5 for groups control, L-16, and L-20 respectively. The positive effect of photobiomodulation treatment on cleavage rate and blastocyst cell number suggests there is a window of sensitivity to 660-665nm light between 16 and 20 hours from start of maturation.
15 Search for Non-Genomic Markers as Puberty Predictors inBos Indicus Cattle
Authors: Campbell Meghan , Rocha Cecilia Constantino C , Cordeiro Andrey , Silva Felipe , Martins Thiago , Bennett Alexandra , Thrift Todd , Rezende Fernanda M , Mateescu Raluca G , Binelli Mario
Published: May 2023

Brahman cattle are used for crossbreeding due to their maternal ability, heat, and parasite tolerance. Brahman displays delayed attainment of puberty compared with taurine breeds. The objective was to identify molecular markers in the blood of prepubertal heifers and bulls that predict early puberty attainment. We hypothesize that Brahmans that attains puberty have a blood metabolite signature that differs from animals that remain prepubertal. Plasma was collected 90 (-90d) and 30 (-30d) days prior to the beginning of the breeding season from 156 yearling Brahman heifers and 28 bulls. Animals were classified as pubertal (pub) or prepubertal (prepub) based on reproductive variables such as the reproductive tract score and pregnancy to insemination for heifers and scrotal circumference and semen quality for bulls. Plasma from 48 pub and 48 prepub heifers and 9 pub and 7 prepub bulls were submitted for quantitative mass spectrometry metabolomics analysis. There was a clear clustering of animals according to puberty status (orthogonal projections of latent structures discriminant analysis). Concentrations of the top three metabolites explaining clustering were analyzed by t-tests. As heifers approached maturity, there was a 3.03-, 11.76- and 2.08-fold change (P < 0.0001) in the concentrations of PC ae C42:3, ProBetaine, and PC ae C42:2 measured at -30 vs. -90 days. Similarly, for bulls, concentrations of HipAcid, C4 and SM (OH) C24:1 were 1.52-, 1.53-, and 1.45-fold greater (P < 0.0001), respectively. Comparing pub vs. prebub heifers on -90 d, there was a 1.26- (P < 0.001), 0.62- (P < 0.01) and 1.11-fold change (P < 0.05) for hArg, Putrescine and AABA concentrations, respectively. Regarding bulls on -90 d, there was a 1.57- (P < 0.01), 1.32- (P < 0.03) and 1.15-fold change (P < 0.03) for FA(18:1), FA(18:2) and DG(16:1_18:2) concentrations, respectively. In conclusion, we discovered potential markers for the prediction of puberty attainment based on plasma metabolomic signatures in Brahman.
19 Relationship Between pH in Vagina and a Successful Pregnancy in Small Ruminant Recipients
Authors: French Sarah-Jane , Runyan Cheyenne L , Cassens Andrew M , Roper David
Published: May 2023

Reproductive efficiency and efficacy are key components of economic return in small ruminant production, therefore utilization of assisted reproductive technologies has increased. Despite advances in assisted reproductive technologies, pregnancy rates per embryo culture and transfer still remain low. The physio-chemical parameter of pH within the female reproductive tract and its potential implications in pregnancy success in caprine remains to be elucidated. The objective of this study was to evaluate vaginal pH and compare pregnancy rate for embryos produced in-vivo and in-vitro in goats. Spanish and Spanish Boer Cross females (n = 78) were estrous synchronized using a progesterone vaginal insert protocol and gonadotropin was administered at time of removal. Embryo grade and stage for conventional fresh embryo transfer and in-vitro fertilization were recorded. Vaginal pH was measured post transfer. At d 45 pregnancy status was determined via trans-abdominal ultrasonography. Successful embryo transfer (ET) was determined by kidding percentages. Data were analyzed using an ANOVA with a multiple linear regression model in GraphPad Prism 9.4. It was found that vaginal pH of females receiving cultured embryos did significantly predict pregnancy detection at d 45 and kidding (P = 0.02). However, the vaginal pH in females receiving fresh embryos had no effect of pregnancy and kidding rates (P = 0.451). While vaginal pH had a correlation with successful kidding of cultured embryos, further research is warranted to determine the relationship between physio-chemical parameters, environmental factors and pregnancy rates in goats.
40 Texel Genetics Increase Muscle Growth by Altering Satellite Cell Characteristics
Authors: Greene Maslyn A , Duckett Susan K
Published: May 2023

The Texel breed is a double muscled breed of sheep that is commonly used as a terminal sire in meat-production. The increase in muscle mass is related to a single nucleotide polymorphism in the myostatin gene, a myokine that inhibits muscle growth. There is limited information on how postnatal skeletal muscle fiber hypertrophy is altered in Texel lambs. Satellite cells or muscle stem cells have a major role in postnatal hypertrophy of muscle fibers. Satellite cells are generally found in a state of quiescence and must activate, proliferate, and differentiate to increase DNA content in myofibers during periods of postnatal muscle growth. The objective of this study was to evaluate muscle fiber hypertrophy and satellite cell proliferation and differentiation in lambs of two sire breeds, Texel or Suffolk. Male lambs of each sire breed (n = 4/sire breed/time) were harvested at d 2, 14, and 203 of age. Muscle samples were collected from the longissimus and snap frozen for examination of myofiber cross-sectional area by fluorescent immunohistochemistry. Another portion of the longissimus was used to isolate satellite cells for in vitro experiments to examine population number, proliferation, and differentiation capacity. Isolated satellite cells were counted, seeded for activation, and grown until colonies reached 80% confluence. Activated cells were seeded for a proliferation assay measuring DNA content daily for 6 days. Following proliferation, cells were differentiated for 4 days, and the number of differentiated nuclei were counted with fluorescent immunohistochemistry. Sire breed did not impact (P < 0.05) the weight of the longissimus; however, muscle ribeye area tended (P < 0.10) to be increased for Texel lambs compared with Suffolk lambs. In the early postnatal period, from d 2 to 14, longissimus mass increased (P < 0.05) by 160%, and ribeye area increased by 100%. Between d 4 and 203 longissimus mass increased (P < 0.05) by 350%, while longissimus area only increased by 100%. Muscle fiber cross sectional area expanded (P < 0.05) from d 14 to 203 of age, and cross-sectional area was greater (P < 0.05) for Texel than Suffolk lambs at d 203. Satellite cell populations per gram of tissue increased (P < 0.05) between d 2 and 14 and decreased from d 14 to 203. The number of satellite cells that activated from quiescence was reduced (P < 0.05) as animal age increased but was not impacted (P > 0.05) by sire breed. Following activation, satellite cell proliferation capacity was greater (P < 0.05) for Texel compared with Suffolk satellite cells. Differentiation capacity was not altered (P > 0.05) by sire breed. Texel-sired lambs had larger longissimus cross-sectional muscle fiber area at d 203 of age than Suffolk. These changes appear to be related to greater proliferation of satellite cells, the stem cells of muscle, to enhance muscle fiber hypertrophy during postnatal growth.
45 Effects of Genomic Residual Feed Intake on Performance, Feed Efficiency and Greenhouse Gas Emissions in Holstein Heifers
Authors: O’Reilly Keara , Carstens Gordon , Johnson Jocelyn R , Deeb Nadar , Ross Pablo
Published: May 2023

The objective of this study was to examine the differences in performance, feed efficiency, and greenhouse gas emissions in Holstein heifers with divergent genomic residual feed intake (RFIg). Holstein heifers (n = 55; initial BW = 351 ± 64 kg) were classified as either low RFIg (n = 29) or high RFIg (n = 26) based on RFIg values determined from their genomic breeding values (Ecofeed index, STgenetics). Heifers were blocked by RFIg, stratified by BW and assigned to 1 of 2 pens, each equipped with 4 electronic feedbunks (GrowSafe Systems), with 1 pen equipped with a GreenFeed real-time gaseous-exchange measurement system (GEM; C-Lock). Heifers were fed a corn-silage based total mixed ration twice daily. Individual dry matter intake (DMI) was collected for 84 d and BW measured weekly. Phenotypic residual feed intake (RFIp) was calculated as the residual from the regression of DMI on average daily gain (ADG) and mid-test BW0.75. As only 1 of the 2 pens had a GEM system, during the 84-day study heifers were rotated between the two pens at 14 day intervals resulting in each group of heifers having three 14-day gaseous exchange measurement periods. A time series analysis of gaseous exchange measurements, with a repeated measure of measurement period, fixed effect of RFIg class and random effect of pen was conducted. A mixed model with RFIg class as fixed effect and pen as a random effect was used for analysis of the other response variables. There were no differences in initial or final BW and ADG for heifers with divergent RFIg; however, the low RFIg heifers consumed 7.3% less (P < 0.05) feed per day than their high RFIg counterparts. Consequently, low RFIg heifers exhibited a more favorable (P < 0.05) RFIp, with a RFIp of -0.188 and 0.211 kg/d for low and high RFIg heifers, respectively. There were no RFIg class by measurement period interactions (P > 0.10) for the greenhouse gas emissions measured. Low RFIg heifers had 7.7% less (P < 0.05) methane emissions (g/d) and 6.1% less (P < 0.05) carbon dioxide production (g/d) than their high RFIg counterparts. However, methane yield (g methane/kg DMI) was similar (P > 0.05) for low and high RFIg heifers. These results indicate that selection for low RFIg has the potential to identify cattle with favorable feed efficiency phenotypes. Additionally, selection based on RFIg provides the opportunity to produce cattle with fewer greenhouse gas emissions. Further research is warranted into selection based on RFIg through genomic indexes to improve feed efficiency and mitigate the environmental impact of cattle production.
41 Effect of Finishing System on Growth, Efficiency, and Carcass Quality of Dairy × Beef Hybrids
Authors: Grote Ally J , Womack Addie , Farran Garrett , Robison Colton A , Beck Paul A , Wilson Blake K , Wistuba Troy , Schroeder Olivia N
Published: May 2023

Our objective was to determine the effect of calf-fed or yearling finishing systems on the performance of dairy-beef crossbred steers. Dairy-beef hybrid steers were acquired from Land O’ Lakes Calf Milk Research Facility at Grey Summit, Missouri at 12-weeks of age and transported to Willard Sparks Beef Research Center (WSBRC). Upon arrival at WSBRC, steers were weighed, vaccinated, treated for parasites, and implanted with 36 mg of zeranol (Ralgro). Alternating groups of steers were placed either directly on finishing diets (FIN) or on high-quality pasture and supplementation for 5 to 6 mo before returning to WSBRC for finishing (GRW/FIN). Once GRW/FIN steers reached 312 ± 7 kg, the steers were returned to WSBRC, weighed, and processed. At WSBRC, steers within each finishing system were sorted by BW into 4 to 5 animal pens. Steers in FIN were re-implanted with Ralgro on d 56, Component TE-IS (80-mg trenbolone acetate,6-mg estradiol, and 29-mg tylosin tartrate; Elanco US, Greenfield, IN) on d 112, and Component TE-S (200-mg progesterone, 20-mg estradiol benzoate, 29-mg tylosin tartrate; Elanco) on d 224. Steers in GRW/FIN were implanted with Component TE-IS at the start of finishing, and Component TE-S on d 20. Steers in FIN were grown on successively greater energy growing diets through d 112, stepping up to a 20% roughage growing diet (18.4% CP and 2.4 Mcal NEg/kg from d 28 to 112. On d 112, FIN steers were transitioned to a finishing diet consisting of 12% roughage, 12% crude protein, and 1.3 Mcal NEg/kg. A final finishing diet (8% prairie hay, 20% Sweet Bran and 62% dry-rolled corn) was fed to FIN steers from d 224 to slaughter. Steers in GRW/FIN were stepped up to the finishing diet when they reached 407 ± 6 kg. Finishing diets for the final 28 d for FIN and GRW/FIN included ractopamine hydrochloride at a rate of 300 mg·steer-1·d-1. Initial and terminal BW were greater (P < 0.01) in steers in the GRW/FIN finishing system. Body weight at reimplant was greater (P < 0.01) for FIN. Steers in the GRW/FIN system were on feed for fewer (P < 0.01) days compared with FIN steers. Average daily gain (ADG) and DMI (kg·steer-1·d-1) were greater (P < 0.01) for GRW/FIN. Steers in GRW/FIN had a greater (P ≤ 0.02) feed:gain ratio than those placed directly into a finishing system. There were no differences (P ≥ 0.10) in USDA Yield Grade, marbling, ribeye area (REA), or back-fat thickness (BFT) between finishing systems. Steers in FIN had a greater (P < 0.01) dressing percentage (DP) and lighter (P ≤ 0.01) hot carcass weight (HCW) than those for GRW/FIN. Finishing system has an impact on performance and efficiency of dairy-beef hybrid steers, but minimal impact on carcass quality.
44 Impacts of Pre- and Postpartum Heat Stress Abatement on Physiology and Performance of GrazingBos Indicus -Influenced Cow-Calf Pairs
Authors: Izquierdo Vinicius , Lazarin Joao , Silva Hiran , Ranches Juliana , Carroll Jeff A , Burdick Sanchez Nicole C , Bittar Joao , Vendramini Joao , Moriel Philipe
Published: May 2023

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.
51 Use of Plant Secondary Metabolites and Impact on Beef Cattle Production
Authors: Flythe Michael D , Harlow Brittany
Published: May 2023

The objective of the presentation is to describe the beneficial roles of plant secondary metabolites in beef production with special attention to mode of delivery. Plant and fungal secondary metabolites are responsible for many well-known problems in beef cattle production, such as acute or chronic intoxication. Fescue toxicosis is an example of the latter. However, there are also beneficial effects of secondary metabolites. Plant extracts (e.g., essential oils) that are rich in phenolic compounds and other secondary metabolites have been explored as alternatives to veterinary prophylactic antibiotics, growth promoting antibiotics, and enteric methane suppressants. An example of extracted botanicals is beta-acid from the hops plant. Beta-acid could be considered a model rumen-active phytochemical because of a similar mechanism of action to ionophores, which allows direct comparison with well-studied, microbially produced drugs. The route of delivery of extracted phytochemicals can also be similar to that of other commercial products. In contrast, other beneficial plant secondary metabolites can be delivered without extraction. Anthelmintic forages have been extensively studied for use in small ruminants. These forages contain concentrations of plant secondary metabolites, such as condensed tannins or sesquiterpene lactones, that reduce parasite load without processing the plant. Similarly, health and production benefits were shown in cattle consuming isoflavones by grazing forage legumes (red clover) or by supplementation with hay or other minimally processed legumes (red clover, white clover, soybean meal). The term, functional feeds, borrows from the idea of functional foods in human nutrition, this is, foods that have a benefit traditionally ascribed to medicine. Functional feeds may have advantages over commercially extracted and processed phytochemicals, not the least of which is the ability of cattlemen to produce their own feed. However, to fully take advantage of beneficial forage plant secondary metabolites more research is needed in animal nutrition, plant sciences, and chemical analysis.
86 Biomarkers of Inflammation in Neonatal Calves Supplemented with Condensed Solubles from Milk Permeate
Authors: Santos Rafaela , Brown Audrey , Senevirathne Nirosh , Sunkesula Venkateswarlu , Osorio Johan , Trevisi Erminio , Rosa Fernanda
Published: May 2023

Neonatal and weaning periods are the most challenging phases for enteric infections in dairy calves. While different approaches are used to minimize calf health issues, the neonatal diet remains the core approach to enhance pre- and post-weaning animal health and performance. Previous studies have shown that bioactive compounds, including oligosaccharides present in the diet of neonatal dairy calves, enhanced their growth performance post-weaning. However, the effects of oligosaccharides supplementation during the neonatal period and the impact on the health status of the calf remain to be elucidated. Thus, we aimed to evaluate blood biomarkers of inflammation in calves supplemented with condensed solubles from milk permeate (CS) during the neonatal period (from birth to 21 d) of dairy calves. Twenty-four newborn Holstein calves (n = 12/group) housed in individual hutches were used in a randomized complete block design study. Calves were blocked by birth date and sex. At 2-days old, calves were randomly assigned into two groups (n = 6 females and 6 males per group): control with no supplement; or treatment with 50 g/d of CS. Both treatment and control groups were fed pasteurized waste milk during the preweaning period. Calves were fed 2.83 L of pasteurized waste milk 2×/d during week 1 to 5, 1×/d in week 6, and weaned at week 7. At each milk feeding during week 1 to 5, 25 g of CS was added to the pasteurized waste milk for each calf on the CS treatment. Healthy scores were recorded daily. Calf growth measurements and blood samples were collected weekly. Data were analyzed using MIXED procedures of SAS 9.4 with repeated measures. Significant differences were declared at P < 0.05. Overall, body weight, fecal and respiratory scores were similar between groups during the preweaning period. During the first 3 weeks of age, a group×sex×time interaction was observed for the enzyme myeloperoxidase (MPO) expressed by neutrophils. Female calves on the CS treatment had decreased MPO concentrations in the blood relative to the female controls at week 3. Other biomarkers of inflammation (i.e., haptoglobin) or consequent liver response (i.e., albumin, paraoxonase) did not differ between groups. Based on these parameters, there was no evidence of systemic inflammation during the first 21 days of age. However, circulating MPO is an indicative of phagocytosis by neutrophils resulting in a local or systemic inflammatory responses. The decreased MPO in CS female calves can be associated with a lesser microbial infiltration in the gut. The latter suggests that oligosaccharides from the diet stimulate the growth of commensal microbiota on the host, which serve as decoy receptors to pathogenic microorganisms (i.e., blocking microbial infiltration). Overall, these findings suggest that bioactive molecules as feed supplements such as CS can help the local immune response in neonatal dairy calves.
85 Evaluation of an Oral Supplemental Cannabidiol Product for Acceptability in Mature Horses
Authors: Leatherwood Jessica L , Leise Julia , Paris Brittany L , George James M , Martinez Rafael , Glass Kati G , Wickersham Tryon A
Published: May 2023

Thirty stock type geldings (15 ± 3 y; 556 ± 63 kg BW) were used in a randomized complete design for a 28-d trial to evaluate the influence of cannabidiol (CBD) oil supplementation on health of mature horses by conducting a blood chemistry panel and evaluating the presence of banned substances. Horses were stratified by BW and age, and randomly assigned to 1 of 3 dietary treatments formulated with canola oil to provide.50 mg CBD/kg BW (TRT1; n = 10), 0.75 mg CBD/kg BW (TRT2; n = 10), or 0.00 mg CBD/kg BW (canola oil; CON; n = 10) only as determined by manufacturer (Arrowhead Labs). Treatments were individually fed and top-dressed onto a commercially available concentrate twice daily at 12 h intervals using attachable feed bags. Diets were formulated to meet or slightly exceed nutritional requirements for mature horses at maintenance. Between meals, horses were maintained in adjacent dry lots and received coastal bermudagrass hay ad libitum. Body weight was obtained, and body condition scores (BCS) were assigned every4 d. On d 0 and 28, blood was collected via jugular venipuncture and serum was harvested to perform a blood chemistry panel and drugs of abuse screening at the Texas Veterinary Medical Diagnostic Laboratory (TVMDL; College Station, TX). Data were analyzed using PROC MIXED of SAS (v9.4), and the model included treatment, time, and the treatment × time interaction for BW and BCS. Blood chemistry variables on d 0 were used as a covariate and the main effect tested was treatment. Linear and quadratic orthogonal polynomial contrasts were used to partition sum of squares. Analysis of supplement samples revealed supplemented products contained lower CBD concentrations then indicated from initial testing. Therefore, horses in TRT1 and TRT2 received an average of 0.13 mg CBD/kg and 0.12 mg CBD/kg BW, respectively. Dietary treatments did not affect concentrate intake, BW, or BCS. Supplementation of CBD did not result in the presence of any banned substances in serum, including CBD, 7-carboxycannabidiol, 7-Nor-7-carboxycannabidiol, and tetrahydrocannabinol (THC). Following 28 d of supplementation, gamma-glutamyl transferase (GGT) responded quadratically (P = 0.06) to treatment, with a peak in GGT in horses receiving TRT2. Serum creatinine concentration tended (P = 0.06) to decrease with increasing inclusion of CBD in the diet. In contrast, the main effect of treatment on Ca concentrations was linear (P = 0.01) and characterized by decreased Ca values for TRT1 compared with TRT2 and CON. Canola based CBD oil was well-accepted by mature horses, banned substances were not detectible in blood, and blood chemistry parameters were not adversely affected as a result of supplementation; however, more information is needed to improve stability of CBD used in dietary products.
90 Exposure to Endophyte-Infected Tall Fescue Negatively Impacts Pulmonary Arterial Pressure in Beef Cattle
Authors: Rajo Edwin Benjamin , Williams Katherine , Weaver Andrew R , Pickworth Carrie L , Foster Derek , Poole Daniel H
Published: May 2023

Fescue toxicosis negatively impacts cattle productivity. Previous data from our laboratory has demonstrated that cattle within a herd respond differently when grazing tall fescue, thus variation within a breed may provide genetic tolerance to the negative effects on performance. Fescue toxicosis results in major impacts on the cardiovascular system, thus it was hypothesized that exposure to ergot alkaloids negatively impacts pulmonary arterial pressure (PAP). The objective of this study was to examine changes in PAP and other production parameters in cattle consuming endophyte-infected tall fescue. Pregnant Angus cows (2 to 4 years; n = 65) were randomly divided to graze either endophyte-infected (EI) or novel endophyte (EN) pastures for4 consecutive weeks starting in April. Weekly measurements were collected to monitor physiological responses to consuming endophyte-infected tall fescue. In addition, PAP was measured every 4 weeks. Data were analyzed using a MIXED procedure of SAS, and statistical significance was determined at P < 0.05 and a tendency at 0.05 < P < 0.10, and evaluated the effects of treatment, age, week, and its interactions on BW, ADG, BCS, HCS, HSS and PAP. Exposure to EI did not affect BW, ADG, or BCS (P >0.05). Whereas, hair coat scores (1-5 scale) were significantly less for cattle consuming EN pastures (2.15 ± 0.05) compared with consuming EI pastures (2.31 ± 0.05; P < 0.05). Additionally, shedding scores (1-5 scale) were reduced in cattle consuming EN pastures (2.3±0.05) compared with consuming EI pastures (2.5±0.05; P< 0.05). There was a significant difference in PAP measurements in cattle exposed to EN pastures (37.16 ± 0.59 mm Hg) compared with EI pastures (31.31 ± 0.56 mm Hg; P < 0.0001). Additionally, PAP scores tended to deviate over the 14-week study between treatment groups (P = 0.0677). As expected, exposure to EI tall fescue resulted in greater HCS and HSS. However, the decrease in PAP in cattle consuming EI fescue was unexpected. Thus, further investigations are needed to examine the interaction between ergot alkaloid exposure on cardiovascular parameters such as PAP to potentially predict genetic differences in beef cattle to identify animals that would have a lower risk of developing fescue toxicosis.
176 Evaluation of Meloxicam Plasma Concentrations Using a Microneedle Patch for Drug Delivery
Authors: Midkiff Kirsten A , Miranda-Munoz Katherine , Weber Wyatt E , Cheek Robin A , Reynolds Jana L , Tsai Tsungcheng Cheng , Bear Misty , Coetzee Johann F , Kegley Elizabeth B , Almodovar Jorge , Powell Jeremy G
Published: May 2023

To evaluate meloxicam plasma concentrations using a microneedle patch, 12 pigs (initial BW = 2.5 ± 0.53 kg) were stratified into of 4 treatment groups. Treatment groups were: 1) pigs (n = 2) received 0.5 mg/kg meloxicam via oral drench (oral); 2) pigs (n = 2) received a patch with no meloxicam (placebo); 3) pigs (n = 4) received microneedle patch dosed at 2.5 mg/kg (low dose); and 4) pigs (n = 4) received 2 microneedle patches dosed at 5 mg/kg (high dose). Blood was collected for plasma analysis at 0, 2, 4, 8, 12, 24, 48, 72, 96, and 168 hours. Microneedle patches were adhered on the pinna of the ear after blood collection at 0 hour. Statistical analyses were performed using the MIXED procedure of SAS 9.4, assessing effects of treatment, time, and treatment × time interaction. Statistical significance was determined at P ≤ 0.05, with tendencies at 0.05 < P ≥ 0.1. There was a treatment × time interaction (P < 0.0001), with the oral treatment group having greater meloxicam plasma concentrations at 2, 4, and 8 hours than placebo, low dose, and high dose treatment groups (P < 0.0001), but there were no differences for 24, 48, 72, 96, and 168 hours (P > 0.1). The oral treatment group tended to have greater meloxicam plasma concentrations at 12 hours compared with placebo (P = 0.09), low dose (P = 0.054), and high dose (P = 0.054) treatment groups. There were no differences between placebo, low dose, and high dose treatment groups for any blood collection timepoint (P > 0.1). Meloxicam concentrations in plasma were detectable but low for both the low dose treatment group (0.21 ng/mL) and high dose treatment group (1.14 ng/mL). Research is continuing to determine the ideal meloxicam dosage needed on the patch to deliver desired plasma concentrations.
135 Growth Performance, Carcass Characteristics, and Methane Emissions of Feedlot Young Bulls
Authors: Rodrigues Barbara , Sarturi Jhones , Samia Leandro , Alvarenga Ramon C , Berndt Alexandre , Souza Fernando , Reis Beatriz Q , Silva Kaliu G
Published: May 2023

The growth performance, carcass characteristics, and methane emissions from feedlot beef cattle fed a high-lipid finishing diet (7.3% of ether extract) were evaluated. Fifty long-yearling young bulls were divided into two groups following their breed composition: Nellore (n = 25) and Angus × Nellore crossbred (n = 25), and randomly assigned into 4 pens (12 or 13 animals/pen) following a completely randomized design. Animals were sourced from the same breeding season and endured a grazing growing phase in Megathyrsus maximus cv. Mombaça pasture, with protein and energy supplement offered at 0.2% of body weight (BW). The feedlot phase comprehended 105 days of feed, and the diet (80% concentrate) was formulated to meet or safely exceed the beef cattle requirements to target an average daily gain (ADG) of 1.6 kg/day, in which major ingredients were represented by (% DM basis): sorghum silage (20%), ground corn (57.6%), ground soybean seed as the lipid source (20.4%), and a mineral/vitamin premix (2%). Titanium dioxide (TiO2) was used as an external marker to estimate dry matter intake (DMI), while 10 g was administered to 12 animals of each group, once daily, for 10 d. Animals were weighed every 30 d after a 16-h fasting period, and the day before slaughter to obtain the final body weight (FBW). Enteric methane emissions were measured using the sulfur hexafluoride (SF6) tracer gas technique in the same animals used for intake measurements. The animals were equipped with gas collection halters attached to pre-evacuated polyvinyl chloride (PVC) sampling canisters with a capillary tube (0.127 mm diameter), made to permit 50% filling in 24 h, for five consecutive days. Data were analyzed using the statistical analysis software R (R CORE TEAM, 2021), and the effect of breed on carcass traits and methane emissions was evaluated using the completely randomized design one-way, in which treatment means were compared by the F test (P < 0.05). The crossbred animals had a greater DMI (12.6 vs.0.6 kg/d), gain efficiency (0.16 vs. 0.14), initial BW upon feedlot phase (509.8 vs. 444.7 kg), FBW (720.8 vs. 595.6, kg), ADG (2.01 vs..44 kg), and hot carcass weight (404.7 vs. 345.0 kg; P < 0.01) compared with Nellore cattle. No difference was observed in dressing percentage between genetic groups (P = 0.28). Nellore animals produced more methane expressed as CH4 g/kg ADG (266.0 vs.73.4; P < 0.01), and tended to produce more methane expressed as CH4 kg/DMI (35.4 vs. 27.7; P = 0.08), and CH4 g/kg CW (1.09 vs. 0.87; P = 0.11). Crossbred F1 Nellore/Angus young bulls showed improved feedlot performance and carcass weight, while not negatively affecting total CH4 production, but rather lessening CH4 emissions per unit of beef produced.
132 Weight and Reproduction Response to a Peanut Skins Plus Corn Supplement Offered to Heifers Grazing Spring Wheat Pasture During Artificial Insemination Breeding
Authors: Gadberry Shane , Moss Nate T , Hess Tom , Hubbell Don S , Looney Charles R , Weber Wyatt E , Rivera Daniel
Published: May 2023

The objective was to assess heifer weight and reproduction response to a peanut skins plus corn supplement during spring wheat grazing. In spring of 2021 and 2022, 10 and 8 pastures (1.62 ha/pasture) of fall overseeded wheat were randomly assigned to supplement (SUP) or control (CONT) constrained to the same number of replications per treatment. Pastures were stocked with 6 heifers/pasture each year. The initial goal was to use peanut skins as a single ingredient; however, testing palatability in year 1, before spring grazing, demonstrated a need to create a mixed supplement for improved acceptance. Over 5 weeks from initiation of grazing to breeding, heifers were transitioned from a 33:67 to a 50:50 peanut skins:corn mix. Supplement was offered at 0.5% BW, as-fed, at the start of spring wheat grazing in early March. An additional 2.4% and 8.3% inclusion of dried molasses was incorporated to further enhance acceptance in year 1 and 2, respectively. Estrus synchronization (ES) began March 31 and April 5 for each year. Data were analyzed across year with year considered as a random effect and pasture the experimental unit. Initial weight was 12 ± 5.8kg greater (P = 0.05) for SUP. Weight at ES tended (P = 0.11) to be 9.4 ± 5.55kg greater for SUP. Reproduction tract score was similar (P = 0.55), averaging 4.2 ± 0.13, and heifers were of similar (P = 0.33) age (405 ± 4.1 days) at time of insemination. Average daily gain from initial wheat grazing until removal for natural service breeding did not differ between treatments (P = 0.92) and averaged 1.0 ± 0.21 kg. Body condition score was similar (P = 0.43) at ES and averaged 5.7 ± 0.7. The heavier initial BW of SUP heifers was sustained through wheat grazing (P = 0.05). Ultrasound determined pregnancies averaged 66.7 and 50.0 ± 6.6% for SUP and CONT, respectively, for an odds ratio of 2.1 ± 0.79 (P = 0.08) at 30 days after insemination. Overall pregnancy rates following natural service averaged 88.9 and 79.6 ± 4.88% for SUP and CONT, respectively with an odds ratio of 2.1±1.12 (P=0.19). High dietary protein has been associated with reduced reproductive performance. Using the peanut skins plus corn supplement was hypothesized to improve reproduction on a high protein diet due to the possible effect of peanut skins tannins on dietary protein utilization and corn altering the rumen degradable protein to organic matter ratio. While the fixed time artificial insemination pregnancy rates for CONT would not be considered poor, there was a tendency for SUP to secure more pregnancies among heifers of similar age, reproductive tract score, and body condition.