Brief Summary of Minutes of Annual Meeting

1. Estimate genetic variation associated with animal health and structural soundness using classical animal breeding and genomic techniques to facilitate sustainable beef cattle production systems.

    1.1 Eye and facial pigmentation

    1.2 Udder conformation

    1.3. Hair Shedding

2. Systems approach to analyzing novel ERTs associated with female production including longevity, fertility, and meat quality database creation.

3. Documentation of genetic components and development of thermotolerance measurements pertaining to heat tolerance adaptive traits in sustainable beef cattle production systems.

Arkansas

Procedures:

Obj. 1.1

We will use photographs and digital quantification software to determine the proportion of eyelid with pigmentation. Each animal will have one photo to identify the animal (primarily have used tag or brand), one of full face straight on to clarify markings, one of eye straight across on left side, one of eye aiming up (to characterize the eyelid under the upper eyelashes) on the left side, one of eye straight across on right side, and one of eye aiming up on the right side. Quantifications of pigmentation will be conducted using procedures developed by Davis et al. (2015).  Multiple locations will contribute to this objective. Evaluated breed types will include 1) Hereford, 2) Hereford-Bos taurus crosses, and 3) Hereford-Bos indicus crosses (including Braford in this category even though it is recognized as a distinct breed). The target number of animals in each breed type category is 2,000.

Obj. 1.2

Cattle will be evaluated for udder conformation traits and scored according to BIF guidelines (2010) for Udder Suspension and Teat size. Scores for each trait range from 1 to 9 with 9 indicating tight suspension and small teat size and will be evaluated at weaning. In addition, any udder abnormalities such as evidence of mastitis, dead quarters, tumors, injuries, or other diseases will be recorded. Cow traits related to weaning performance and calf traits to include birth weight and date, weaning weight and date and post weaning performance will be evaluated.

Obj. 1.3

Cattle will be evaluated for hoof conformation traits and scored according to American Angus Association (2015) for Claw Set and Toe Angle. Scores for each trait range from 1 to 9 with 1 indicating straight pasterns and short toes, and 9 indicating curled toes and crossed claws. Hooves will be evaluated at weaning. Additionally, trim records will be recorded. Cow traits related to reproductive performance and calf traits to include birth weight and date, weaning weight and date and post weaning performance will be evaluated.

Obj. 3.2

Documentation of genetic components pertaining to heat tolerance adaptive traits in sustainable beef cattle production systems. Cattle will be evaluated for hair shedding scores from March through July (28 day intervals, 5 scores). Shedding scores will on a 1 through 5 scale:  where 1 = slick short summer coat (100% shed); 2 = hair coat is mostly shed (75% shed); 3 = hair coat is halfway shed (50% shed); 4 = hair coat exhibits initial shedding (25% shed); and 5 = full winter coat (0% shed).  In addition, cow traits related to reproductive performance, growth performance, and culling will be recorded. Calf traits to be recorded include birth weight and date, weaning weight and date.

Progress of Work:

Obj. 1.1

The objective was to document using digital photographs a determination of proportion of the eyelid pigmentation in white-faced cows housed at the University of Arkansas beef research unit near Fayetteville.

An Angus-based fall calving cowherd (n ≈ 167) was observed, and photos of eye pigmentation were collected from white-faced cows and calves at weaning.  Whole blood samples were also collected and frozen from calves. Cow traits related to weaning performance and calf traits to include birth weight and date, weaning weight and date were recorded for possible future evaluation.  Photos and whole blood will be transferred to Dr. Riley at TAMU to collaborate with other locations that are involved with collecting similar data.

Obj. 1.2

The objective of this study was to determine if any relationships existed between udder conformation and production traits in cows housed at the University of Arkansas beef research unit near Fayetteville.

An Angus-based fall calving cowherd (n ≈ 174) was observed, and udder scores were recorded at calving in the Fall of 2023 and at weaning in May 2024 on cows ranging in age from two to thirteen years grazing endophyte-infected tall fescue.  Cows were evaluated on a scale from 1 to 9 for udder suspension and teat size according to BIF guidelines. A score of 1 indicated a very pendulous suspension and large, balloon shaped teats and a score of 9 represented a tight suspension and refined teat size. Phenotypic data for cow age, Pre-Breeding BW, Pre-Breeding BCS, BCS of cow at weaning, BW of cow at weaning, AI pregnancy and overall pregnancy, along with calf weaning weight, and adjusted 205-day weaning weight (adjusted for dam age and calf gender) were collected. Means will be generated for suspension and teat scores by dam age. 4 categories of scores were created to combine categorical scores.  Cows receiving a suspension or teat score of 8-9, 6-7, 4-5 and 1-3 were given scores of 1,2,3 and 4 respectively.  Cow performance data will be analyzed using the acceptability parameters described with CORR, GLIMMIX, MIXED, and FREQ procedures of SAS.  Significance was declared at P ≤ 0.05 and tendencies were observed at 0.05 < P ≤ 0.10.

Frequency of cows in the “2” category far outweighed other categories followed by “3” and then “1”.  Udder Suspension at weaning had a significant effect on body weight in that the cows in the “2” category was significantly lower that “1” and “3” (p=0.0001) and those cows in the “3” (5.4) category was significantly higher for BCS than “2” (4.93) (p=0.0009). Weaned calf performance was not significantly different for Udder suspension or teat size (P > 0.24). Calf weaning weight was not affected by udder conformation (P > 0.68, P>0.17 respectively) Udder confirmation did not affect overall AI conception rates or overall pregnancy rates.

Obj. 1.3

The objective of this study was to determine if any relationships existed between foot soundness and production traits in cows housed at the University of Arkansas beef research unit near Fayetteville.

An Angus-based fall calving cowherd (n ≈ 179) was observed, and foot scores were recorded at weaning in May 2022.  Cows were evaluated on a scale from 1 to 9 for foot angle and claw set according to the American Angus Association with 1 indicating straight pasterns and short toes, and 9 indicating curled toes and crossed claws. Phenotypic data for cow age, Pre-Breeding BW, Pre-Breeding BCS, BCS of cow at weaning, BW of cow at weaning, AI pregnancy and overall pregnancy, along with calf weaning weight, and adjusted 205-day weaning weight (adjusted for dam age and calf gender) were collected. Means will be generated for suspension and teat scores by dam age. We assigned 4 categories of scores were created to combine categorical scores.  Cows receiving a suspension or teat score of 8-9, 6-7, 4-5 and 1-3 were given scores of 1,2,3 and 4 respectively. Cow performance data will be analyzed using the acceptability parameters described with CORR, GLIMMIX, MIXED, and FREQ procedures of SAS.  Significance was declared at P ≤ 0.05 and tendencies were observed at 0.05 < P ≤ 0.10.

Mean frequency of Category 2 were substantially higher (148 cows) and cow age of category 3 were younger.  There were no significant effects on any performance traits for claw set or foot angle.

Obj. 3.2

The objective of this study was to measure variation in hair coat shedding and determine if cowherd production performance traits were affected by timing of winter haircoat shedding in cows housed at the University of Arkansas beef research unit near Fayetteville.

An Angus-based commercial beef cattle herd (n ≈ 200) was observed in 2023. Once monthly from March until July, at approximately 28-day intervals, mature cows and replacement heifers were evaluated for shedding on a scale from 1 to 5. A score of 5 indicates a full winter coat and a score of 1 represents a slick, short summer coat. Month of first shedding was defined as the month in which a cow received a hair coat score of 3 (approximately 50% shed) or less was reached. Hair coat scores were taken from April through July. Those that had not received a hair coat score of 3 by July were labeled “no shed”. Phenotypic data for cow age, pregnancy success, calf birth weight, weaning weight and adjusted weaning weight, and cow weaning weight and body condition score were collected and analyzed using the PROC FREQ and PROC GLIMMIX procedures of SAS. Significance was declared at P ≤ 0.05 and tendencies were observed at 0.05 < P ≤ 0.10.

Frequency of MFS occurred with the following order: June> July>May>No Shed>April. Cow age tended to be different (P = 0.06) with MFS group means for May = 4, June = 4.8, July = 4, and No Shed = 3. Pregnancy by artificial insemination success was affected by MFS, with dams that shed by May, June, and July having greater AI conception rates than dams that did not shed (≥ 60% vs. 0%; P = 0.0212). Overall pregnancy rates were not affected by shedding scores (P = 0.42). Cow weaning body weight was different among hair shedding groups (P = 0.0071), as cows that shed by May and June had greater body weights than cows that shed in July. Additionally, weaning body condition scores tended to differ (P = 0.0698) with cows shedding by June having a greater body condition than cows shedding by July. Calf weaning weight and adjusted weaning weight was not significantly different; however, calf birth weight differed (P = 0.0102) with mean birth weight averaging 70, 69, 64, and 60 pounds for calves born to cows that shed in May, June, July and No Shed.  Calf birth weights were greater for dams that shed by May and June compared to dams that shed by July (P ≤ 0.01). Also, cows that shed by May and June tended to have greater calf birth weights compared to No Shed cows (P ≤ 0.07). Calving intervals were not different between shedding groups (P = 0.41).

Florida

Procedures:

Obj. 2:

Collection of phenotypic data from Bos Indicus influenced populations (growth, ultrasound, carcass, meat palatability, fatty acid composition, mineral composition).

A total of 1,066 Brangus steers from the Seminole Tribe of Florida, Inc. born in 2014 and 2015. Cattle were fed at a contract feeder where they were provided a standard feedlot diet consisting of corn, protein, vitamins, and minerals until they reached a subcutaneous fat thickness over the ribeye of approximately 1.27 cm. As cattle achieved appropriate degrees of back fat thickness, they were transported to a commercial packing plant (FPL Food LLC., Augusta, Georgia) where they were harvested in 2016 and 2017 under USDA FSIS inspection. At 48 hours postmortem, carcasses were ribbed between the 12^th and 13^th rib, per industry standard and the following carcass measurements were evaluated for each animal according to USDA standards: hot carcass weight (HCW; kg); marbling score; fat over the ribeye (FOE; cm); and ribeye area (REA; cm²).

Following carcass evaluation, one exposed 2.54 cm thick ribeye steak was removed from the longissimus lumborum of each carcass, posterior to the 12th rib. The steaks were kept on ice and transferred to the University of Florida Meat Processing Center (Gainesville, Florida). Steaks were then trimmed of external fat and connective tissue. A thin shaving across the entire surface of the steak was removed from each sample and frozen at -20 °C for subsequent fatty acid composition, mineral concentration, and DNA extraction.

Fatty Acid Extraction and Gas Chromatography Analysis

Fatty acid extraction was performed as described in Flowers et al. (2018). FA extraction and analysis was performed at the W. M. Keck Metabolomics Research Laboratory, Iowa State University (Ames, IA). About 200 mg of finely ground steak sample was dissolved in 1 mL of 2:1 Chloroform-Methanol mixture. The extracted fats were trans-esterified with 25% Sodium Methoxide in methanol. The resulting Fatty Acid Methyl Esters (FAMEs) were extracted into hexane. For detection, 1 µl of sample was injected into Agilent 7890A GC-FID instrument, a Gas Chromatograph equipped with a flame ionization detector for separation and quantification of the FAMEs. The analysis was performed on Agilent CP-Wax 52CB column (15m, 0.32mm, 0.5µm). The oven temperature program was as follows: initial temperature of 100 °C, increased by 2 °C/min to 170 °C, then increased by 0.5 °C/min to 180 °C, finally increased by 1 °C/min to a temperature of 250 °C and held for three minutes. The inlet and detector temperatures were 250 and 220 °C, respectively. Helium was used as the carrier gas and Supelco 37 FAME mix (Catalog # CRM47885 SUPELCO) was used to generate the calibration curve for identification and quantification of FAMEs. Because marbling is a measure of intramuscular fat and because fat content measures are skewed, for analysis, measured FA were expressed as percentages of the total fat and further classified as saturated, monounsaturated, or polyunsaturated.

Mineral Analysis

Mineral content was measured using inductive coupled plasma-optical emission spectroscopy (ICP-OES, SPECTRO Analytical Instruments, Mahwah, NJ) as described in Mateescu et al. (2013a and 2013b) and Flowers et al. (2018). Briefly, finely ground steak samples were dried at 105 °C over an 18 hour period according to AOAC official methods 934.01 (Davis and Lin, 2005). Moisture content was calculated, and dried samples were processed using a closed-vessel microwave digestion (CEM, MDS-2000, Matthews, NC) in 5 ml concentrated nitric acid and 2 ml 30% hydrogen peroxide according to AOAC official methods 999.10 (Jorhem et al., 2000). The microwave was programmed as follows: 250 W for 5 min, 630 W for 5 min, and 500 W for 20 min followed by a 15 min resting period. Samples were then diluted in deionized water and concentrations of calcium, copper, iron, magnesium, zinc, potassium, sodium, and phosphorus were measured by ICP-OES.

Results

Brangus cattle had palmitic acid levels as low as 21%, and stearic acid levels as high as 26%, which is notable since stearic acid is considered to have a neutral or potentially beneficial impact on cholesterol levels, unlike other saturated fats. Additionally, Brangus cattle had oleic acid levels as high as 53%, enhancing the meat's nutritional value, and sensory qualities, thereby aligning with consumer preferences for healthier and tastier beef. The study also showed linoleic acid concentrations as high as 12% in Brangus cattle, an essential omega-6 FA crucial for human health, highlighting the Brangus breed's potential for providing nutritionally enriched beef. Saturated FA showed weak negative correlations (-0.06 to -0.15) with hot carcass weight, marbling, and fat over ribeye, similar to polyunsaturated FA which had moderate negative correlations (-0.19 to -0.37) with these traits. Conversely, monounsaturated FA were positively correlated (0.16 to 0.34) with these traits, suggesting that higher levels of monounsaturated FA, particularly oleic acid, are associated with improved meat quality and consumer-desirable traits such as increased marbling. The study also highlighted a unique relationship in Brangus cattle, where higher marbling is linked with increased monounsaturated FA and decreased saturated FA, differing from other breeds where increased intramuscular fat typically raises FA saturation levels. Overall, the study underscores the intricate relationships between FA composition, mineral content, and meat quality traits, with implications for breeding and nutrition strategies aimed at improving meat quality and healthfulness.

Obj. 3:

Collection of phenotypic data describing thermal tolerance in Bos Indicus influenced populations and characterization of the genetic component underlying these traits.

This study utilized 1,681 two-year old commercial Brangus replacement heifers from the Seminole Tribe of Florida, Inc. in Okeechobee FL, and 720 one-year old commercial Brangus replacement heifers from Williamson Cattle Company in Chiefland, FL. Samples and measurements were collected from groups of 150-200 heifers during the summer. This occurred in the following periods: from July 31st to August 21st in 2017, from July 25th to August 15th in 2018, on July 26th and August 9th in 2021, and on July 27th and August 3rd in 2022. Animals from the Seminole Tribe of Florida, Inc. were measured in eight collection groups during 2017 and 2018, while the Williamson Cattle Company heifers were measured in 4 groups during 2021 and 2022.

Skin histology preparation

Skin biopsies were collected from the shoulder, 4 inches down from the spine and halfway along the horizontal axis. The skin was cleaned and disinfected using 70% ethanol and chlorhexidine solution (Clorhexidine 2%; VetOne, Boise, ID), sprayed with 4% Lidocaine Tropical Anesthetic Spray, then punched with a 6-mm biopsy punch (Biopsy Punch, Miltex Inc., PA). Biopsies were placed in 10% formalin and stored at room temperature for 16 – 24 h to allow for fixation. Using a razor blade, biopsies were sliced vertically in half and placed cut side down in 70% ethanol-soaked cassettes. Samples were dehydrated in 70% ethanol, infiltrated in liquid paraffin, and stored until sectioned and stained at the UF Molecular Pathology Core. Sections were cut on a microtome with a thickness of 7μm and four sections from each animal were placed on one slide and stained with Harros-Eosin Hematoxylin. Histology slides were photographed using a Nikon T3000 inverted phase microscope (DMZ1200F with NIS Image Elements software) and phenotypes of interest were measured using computer software, ImageJ [9]. One of the four sections was selected based on clear visualization of phenotypes of interest for further analysis. A total area of 1100 × 1100 pixels was used on each picture.

Sweat gland phenotypes

Sweat gland phenotypes included: sweat gland area (mm², Fig. 1) measured as the total area occupied by sweat glands in the 1100 × 1100-pixel image section, sweat gland depth (mm, Fig. 1) as the distance from the top of the sweat glands to the skin surface, and sweat gland length (mm, Fig. 1) as the difference between the bottom of the sweat gland to the skin surface and the top of the sweat gland to the skin surface. Sweat gland depth and length were measured in two different locations on each histology slide and the average of the two measurements was used for statistical analysis. Pixels were converted to millimeters using the following conversion formula: 1,000 pixels = 2.145mm.

All animals were genotyped with the Bovine GGP F250K, and BLUPF90 software was used to estimate genetic parameters and for Genome Wide Association Study.

Results

Sweat gland phenotypes heritability ranged from 0.17 to 0.42 indicating a moderate amount of the phenotypic variation is due to genetics, allowing producers the ability to select for favorable sweat gland properties. A weighted single-step GWAS using sliding 10kb windows identified multiple Quantitative trait loci (QTLs) explaining a significant amount of genetic variation. QTLs located on BTA7 and BTA12 explained over 1.0% of genetic variance and overlap the ADGRV1 and CCDC168 genes, respectively. The variants identified in this study are implicated in processes related to immune function and cellular proliferation which could be relevant to heat management. Breed of Origin Alleles (BOA) were predicted using local ancestry in admixed populations (LAMP-LD), allowing for identification of markers’ origin from either Brahman or Angus ancestry. A BOA GWAS was performed to identify regions inherited from particular ancestral breeds that might have a significant impact on sweat gland phenotypes.

Mississippi

Procedures:

Obj. 1.1:

Photographs of each eye were taken on purebred Hereford and Hereford-cross calves to assess eye pigmentation. Pictures will be sent for quantification and contribution to this objective.

Obj. 1.2:

Data were collected on fall calving purebred Angus, Hereford cows and spring calving commercial cows. Udder and teat scores were recorded within 24 hours after calving, during mid-lactation and at weaning. Data will be combined with other stations at the end of the project for analysis.

Obj. 2:

Cow performance and fertility data were collected from fall and spring calving herds and will be combined with other stations at the end of the project for analysis.

Obj. 3:

Hair shedding scores and BCS were collected on all spring and fall calving cows.

Progress of Work:

For objective 1.1 and 1.2 and 3.2, data were collected for pooling with other stations for an overall analysis.

Obj. 1.1:

Pictures were taken of both eyes for 66 head of purebred Hereford and Hereford Angus cross females

Obj. 1.2:

Udder and teat scores were taken on 51 Angus and 21 purebred Hereford cows at birth, mid-lactation, and weaning.

Obj. 2:

Cow performance and fertility data were collected on 51 Angus and 19 Hereford purebreds and 69 commercial (Simbrah X Angus, Hereford X Angus) females.

Solubility and degradation of inositol in a rumen environment

The accumulation of myo-inositol, a fertility-promoting molecule found in the body, has been shown to enhance breeding performance and pregnancy success in both males and females across several species, including cattle (Martins, et al., 2022). There have also been studies that show positive reproductive effects of oral supplementation in men and women. However, oral supplementation of inositol to ruminant species has not been evaluated. It is unknown if inositol is soluble in the rumen environment, if it is degraded by the microbial populations which exist in this environment, or the timeframe of any potential ruminal degradation of the molecule resulting from oral supplementation. The objectives of this study were to 1) evaluate disappearance (solubility) of different forms of inositol (myo-,and chiro-) and Pyrroloquinoline Quinone (PQQ); and 2) to quantify the in-vitro ruminal degradability of myo-inositol over time. Inositol (0.25g) was placed in Ankom bags and heat sealed. The bags were placed in glass fleakers with an artificial saliva solution and rumen fluid, then incubated at 39 C in a warm shaker bath to simulate ruminal digestion. For the first trial, two bags of myo-inositol, chiro-inositol, and PQQ were removed from incubation at 1, 2, 4, 8, 12, 24, and 48 hr. post initial incubation. These were then evaluated for disappearance of each form of inositol from the Ankom bag and repeated for a total of five replicates. For the second trial, only myo-inositol was evaluated. In addition to bag removal at the same time points, duplicate ruminal fluid samples were collected for myo-inositol concentration determination. This trial had seven replicates. For all forms of inositol 0.00% was removed at 0 hr., and by 1 hr. 99.0 % inositol had disappeared (P > 0.05). There were two exceptions, PQQ-inositol, at 1 hr. was less (P < 0.0001; 96.33 %) and at 4 hr. (98.46 %). For the second trial, myo-inositol disappearance increased (P = 0.0001) from 0.00 % at 1 hr. to 99.53 % at 1 hr. and remained constant (P > 0.05) for subsequent sampling times. Ruminal fluid concentration of myo-inositol increased (P < 0.0001) from 0.197 to 5.39 g/L, and remained constant (P > 0.05) until hour 24 when it had decreased (P < 0.0001) to 2.766 g/L, and decreased (P, 0.0001) further by 48 hours to 0.377 g/L. Ruminal concentration of myo-inositol was not different (P > 0.05) between 0 hr. and 48 hr. This data indicates that inositol is soluble in the rumen environment, though not immediately, with inositol concentrations peaking between 12 and 24 hours and disappearing mostly by hour 48.

Obj. 3:

Hair shedding scores were collected on 51 Angus and 19 Hereford purebreds and 69 commercial (Simbrah X Angus, Hereford X Angus) females.

Texas

Procedures:

Obj 1.1:

1. Approximately 150 calves with records
2. Graduate student at North Dakota State University is analyzing data associated with images.
3. Machine learning algorithms are being implemented to quantify eye pigmentation in various eye structures.
4. Over 6,000 animals with images.

Obj. 1.2:

Consolidation of data into single spreadsheet for analyses.

Brahman and Hereford crossbred cows, two scores collected near parturition, mid-lactation (June) and post weaning.

Obj. 2:

Data accumulated on approximately 1,000 producing females in 2023-2024.

Obj. 3:

Consolidation of data into single spreadsheet for analyses.

Arkansas

Midkiff, K. A., Kegley, E. B., Krumpelman, B., Kutz, B. R., Powell, J. G. (2022). Evaluation of winter hair coat shedding on cow and calf performance in crossbred Angus cattle in Arkansas Journal of Animal Science (Suppl. S3 ed., vol. 100, pp. 208). DOI:10.1093/jas/skac247.378

Florida

Hernandez, A.S., Zayas, G.A., Rodriguez, E.E., Sarlo Davila K.M., Rafiq F., Andrade A.N., Titto CG, and Mateescu, R. G. Exploring the genetic control of sweat gland characteristics in beef cattle for enhanced heat tolerance. J Animal Sci Biotechnol 15, 66. https://doi.org/10.1186/s40104-024-01025-4

Zayas, G. A., Rodriguez, E. E., Hernandez, A. S., Rezende, F. M., and Mateescu, R. G. Exploring genomic inbreeding and selection signatures in a commercial Brangus herd through functional annotation. J Appl Genetics. doi: 10.1007/s13353-024-00859-y

Pantoja MH, Novais FJ, Mourão GB, Mateescu RG, Poleti MD, Beline M, Monteiro CP, Fukumasu H, and Titto CG. 2024. Exploring candidate genes for heat tolerance in ovine through liver gene expression. HELIYON. doi: https://doi.org/10.1016/j.heliyon.2024.e25692

Martins T, Rocha CC, Driver J, Rae DO, Elzo MA, Mateescu RG, Santos J and Binelli M. 2024. Intermediate Proportion of B. Indicus Genetics Favors the Productivity of Crossbred Beef Cows Reared in Subtropical Conditions. http://dx.doi.org/10.2139/ssrn.4671040

Andrade Pantoja MH, Poleti MD, Novais FJ, Souza Duarte KK, Mateescu RG, Mourão GB, Coutinho LL, Fukumasu H, and Titto CG. 2023. Skin transcriptomic analysis reveals candidate genes and pathways associated with thermotolerance in hair sheep. International Journal of Biometeorology. 68:435–444. doi.org/10.1007/s00484-023-02602-4

Hoorn QA, Zayas GA, Rodriguez EE, Jensen LM, Mateescu RG, Hansen PJ. Identification of quantitative trait loci and associated candidate genes for pregnancy success in Angus-Brahman crossbred heifers. 2023. J Anim Sci Biotechnol. 4(1):137. doi: 10.1186/s40104-023-00940-2.

Mateescu R.G., K.M. Sarlo Davila, A.S. Hernandez, A.N. Andrade, G.A. Zayas, E.E. Rodriguez, S. Dikmen, and P.A. Oltenacu. 2023. Impact of Brahman genetics on skin histology characteristics with implications for heat tolerance in cattle. Frontiers in Genetics.14:1107468. doi: 10.3389/fgene.2023.1107468

Texas

Young, C.L., D.G. Riley, R.D. Randel, and T.H. Welsh, Jr.  2023.  Factors affecting antibody-mediated immune response and cellular-mediated immune response in weaned Brahman calves.  Ruminants 3:385–400.  https://doi.org/10.3390/ruminants3040032

Earnhardt-San, A.L., E.C. Baker, D.G. Riley, N. Ghaffari, C.R. Long, R.C. Cardoso, R.D. Randel, and T.H. Welsh, Jr.  2023.  Differential expression of circadian clock genes in the bovine neuroendocrine adrenal system.  Genes 14:2082. https://doi.org/10.3390/genes14112082

Dodd, L.T., D.P. Anderson, D.G. Riley, and A.D. Herring.  2024.  Economic-impact variability among F1 Nellore-Angus herd sires reared together and used in multiple-sire mating groups.  Appl. Anim. Sci.  40:69–79.  https://doi.org/10.15323/aas.2023.02419

Ruiz-De-La-Cruz, G., A.M. Sifuentes-Rincón, F.A. Paredes-Sánchez, G.M. Parra-Bracamonte, E. Casas, D.G. Riley, G.A. Perry, T.H. Welsh, Jr., and R.D. Randel. 2024.  Analysis of nonsynonymous SNPs in candidate genes that influence bovine temperament and evaluation of their effect in Brahman cattle.  Mol. Biol. Rep.  51:285.  https://doi.org/10.1007/s11033-024-09264-4

Munguía Vásquez, M.F., C.A. Gill, P.K. Riggs, A.D. Herring, J.O. Sanders, and D.G. Riley.  2024.  Genetic evaluation of crossbred Bos indicus cow temperament at parturition.  J. Anim. Sci.  102:1–10.  https://doi.org/10.1093/jas/skae022

Baker*, E.C., II, A.E. Earnhardt, K.Z. Cilkiz*, B.P. Littlejohn, R.C. Cardoso, N. Ghaffari, C.R. Long, P.K. Riggs, T.H. Welsh Jr., and D.G. Riley.  2023.  Stress, DNA methylation and their implications in cattle production.  Proc. 69th Annual Texas A&M Beef Cattle Short Course.  Pages 350 to 355.

Riley, D.G., M.F. Munguía Vásquez, A.D. Herring, C.A. Gill, P.K. Riggs, and J.O. Sanders.  2023.  Genetics of bovine temperament and cow temperament at parturition.  Proc. Northern Beef Res. Update Conf.  North Australia Beef Research Council.