T H Welsh

Texas A&M University, College Station, Texas, United States

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Publications (109)255.5 Total impact

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    ABSTRACT: Testicular steroidogenesis and spermatogenesis are negatively impacted by stress-related hormones such as glucocorticoids. The effects of two injections of a therapeutic dose of dexamethasone (a synthetic glucocorticoid, 0.1mg/kg; i.v.) given 24h apart to each of three stallions were investigated and compared to three saline-injected control stallions. Dexamethasone decreased circulating concentrations of cortisol by 50% at 24h after the initial injection. Serum testosterone decreased by a maximum of 94% from 4 to 20h after the initial injection of dexamethasone. Semen parameters of the dexamethasone-treated stallions were unchanged in the subsequent two weeks. Two weeks after treatment, stallions were castrated. Functional genomic analyses of the testes revealed that, of eight gene products analyzed, dexamethasone depressed concentrations of heat shock protein DNAJC4 and sperm-specific calcium channel CATSPER1 mRNAs by more than 60%. Both genes are expressed in germ cells during spermiogenesis and have been related to male fertility in other species, including humans. This is the first report of decreased DNAJC4 and CATSPER1 mRNA concentrations in testes weeks after dexamethasone treatment. Concentrations of these mRNAs in sperm may be useful as novel markers of fertility in stallions. Copyright © 2014 Elsevier B.V. All rights reserved.
    Animal reproduction science. 12/2014;
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    ABSTRACT: Previously, it was reported that intraluteal implants containing prostaglandin E1 or E2 (PGE1 and PGE2) in Angus or Brahman cows prevented luteolysis by preventing loss of mRNA expression for luteal LH receptors and luteal unoccupied and occupied LH receptors. In addition, intraluteal implants containing PGE1 or PGE2 upregulated mRNA expression for FP prostanoid receptors and downregulated mRNA expression for EP2 and EP4 prostanoid receptors. Luteal weight during the estrous cycle of Brahman cows was reported to be lesser than that of Angus cows but not during pregnancy. The objective of this experiment was to determine whether intraluteal implants containing PGE1 or PGE2 alter vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), angiopoietin-1 (ANG-1), and angiopoietin-2 (ANG-2) protein in Brahman or Angus cows. On Day 13 of the estrous cycle, Angus cows received no intraluteal implant and corpora lutea were retrieved, or Angus and Brahman cows received intraluteal silastic implants containing vehicle, PGE1, or PGE2 on Day 13 and corpora lutea were retrieved on Day 19. Corpora lutea slices were analyzed for VEGF, FGF-2, ANG-1, and ANG-2 angiogenic proteins via Western blot. Day-13 Angus cow luteal tissue served as preluteolytic controls. Data for VEGF were not affected (P > 0.05) by day, breed, or treatment. PGE1 or PGE2 increased (P < 0.05) FGF-2 in luteal tissue of Angus cows compared with Day-13 and Day-19 Angus controls but decreased (P < 0.05) FGF-2 in luteal tissue of Brahman cows when compared w Day-13 or Day-19 Angus controls. There was no effect (P > 0.05) of PGE1 or PGE2 on ANG-1 in Angus luteal tissue when compared with Day-13 or Day-19 controls, but ANG-1 was decreased (P < 0.05) by PGE1 or PGE2 in Brahman cows when compared with Day-19 Brahman controls. ANG-2 was increased (P < 0.05) on Day 19 in Angus Vehicle controls when compared with Day-13 Angus controls, which was prevented (P < 0.05) by PGE1 but not by PGE2 in Angus cows. There was no effect (P > 0.05) of PGE1 or PGE2 on ANG-2 in Brahman cows. PGE1 or PGE2 may alter cow luteal FGF-2, ANG-1, or ANG-2 but not VEGF to prevent luteolysis; however, species or breed differences may exist.
    Theriogenology 08/2014; · 2.08 Impact Factor
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    ABSTRACT: Testicular cell proliferation and differentiation is critical for development of normal testicular function and male reproductive maturity. The objective of the current study was to evaluate histoarchitecture, expression of genes marking specific cells and important functions, as well as testosterone production of the developing goat testes. Testes were harvested from Alpine bucks at 0, 2, 4, 6, and 8 mo of age (n = 5/age group). Paired testes weight increased from 2 to 4 (P < 0.001) and 4 to 6 mo (P < 0.01). The greatest increases in seminiferous tubule and lumen diameters, and height of the seminiferous epithelium occurred between 2 and 4 mo (P < 0.001). Genes expressed in haploid germ cells [Protamine1 (PRM1), Outer Dense Fiber protein 2 (ODF2), and Stimulated by Retinoic Acid gene 8 (STRA8)] increased dramatically at the same time (P < 0.001). Expression of other genes decreased (P < 0.05) during testicular maturation. These genes included P450 side chain cleavage (CYP11A1), Sex determining region Y-box 9 (SOX9), Insulin-like Growth Factor 1 Receptor (IGF1R), and Heat Shock Protein A8 (HSPA8). The Glutathione S-Transferase A3 (GSTA3) gene, whose product was recently recognized as a primary enzyme involved in isomerization of androstenedione in man and livestock species including goats, sheep, cattle, pigs, and horses, uniquely peaked in expression at 2 mo (P < 0.05). Follicle-Stimulating Hormone Receptor (FSHR) mRNA abundance tended to steadily decrease with age (P = 0.1), while Luteinizing Hormone Receptor (LHCGR) mRNA abundance in testes was not significantly different across the ages. Testosterone content per g of testicular tissue varied among individuals. However, testosterone content per testis tended to increase at 6 mo (P = 0.06). In conclusion, major changes in cellular structure and gene expression in goat testes were observed at 4 mo of age, when spermatogenesis was initiated. Male goats mature rapidly and represent a good model species for the study of agents that enhance or impair development of testicular functions.
    Journal of animal science. 08/2014;
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    ABSTRACT: Abstract Text: The objectives of this study were to determine if prenatal stress (PNS) or postnatal temperament affect age and BW at first sperm, puberty and sexual maturity. Based on temperament pregnant Brahman cows were assigned to a control (n=44; C) or transport group (n=45; transportation stress for 2 h on 60, 80, 100, 120 and 140±5d of gestation; PNS). At weaning bulls (n=25 C and n=18 PNS) were selected for this study. Temperament was assessed at weaning using temperament score [TS; (PS+EV)/2], pen score (PS; 1=Calm and 5=Excitable), and exit velocity (EV=m/s). These TS were then converted into temperament classes of calm (TS= < 1.78, n= 26), intermediate (TS=1.7 to 2.90, n= 9) and temperamental (TS= > 2.90, n= 8). Bulls were measured every 2 wk from 10 mo of age for BW, scrotal circumference (SC), and right and left testis length. Electroejaculation was used to collect semen when SC reached 24 cm. Semen was analyzed for sperm motility and concentration using a hemacytometer. Sexual maturation was characterized by first sperm (the first visible sperm in the ejaculate), puberty (50 X 106 sperm in the ejaculate) and sexual maturity (500 X 106 sperm in the ejaculate). Paired testes volume (PTV) was calculated as PTV=[0.0396125 X (average testes length) X (SC) 2]. Dependent variables were analyzed using repeated measures, mixed linear models. Fixed effects included temperament class, treatment, and interaction effects. Random animal effects were across repeated days. Age at first sperm, puberty and sexual maturity were similar between C and PNS bulls (P=0.47, 0.73, 0.99, respectively). Times between first sperm and puberty (P=0.32) and puberty to sexual maturity (P=0.92) were not affected by PNS. Temperamental bulls had a greater (P=0.009) time (69.25±11.45 d) from puberty to sexual maturity than calm (28.47±7.53 d) or intermediate bulls (38.19±9.95 d). BW at first sperm was greater for PNS (382.16±11.29 kg) than C bulls (353.19±10.55 kg). Scrotal circumference at first sperm was greater (P=0.03) in temperamental (26.8±0.7 cm) than calm (25.5±0.5 cm) or intermediate (25.1±0.6 cm) bulls. There was a tendency for temperamental bulls to have a greater PTV at first sperm (P=0.06) and sexual maturity (P=0.07) than calm or intermediate bulls. While PNS influenced BW, SC and PTV at first sperm, ages at puberty or sexual maturity were not affected by PNS. Temperamental bulls had retarded sexual development between puberty and sexual maturity. Keywords: prenatal stress, temperament, bull sexual maturity
    2014 ADSA-ASAS-CSAS Joint Annual Meeting; 07/2014
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    ABSTRACT: Abstract Text: The effect of prenatal transportation stress (PNS) on secretion of LH before and after GnRH stimulation in sexually mature Brahman bulls was studied in 12 control and 11 PNS bulls. Control bulls were derived from non-transported pregnant cows, and PNS bulls were derived from cows transported for a 2-h period at 60, 80, 100, 120, and 140 ± 5 d of gestation. Temperament of each bull was assessed at weaning by pen score (PS; 1 = calm and 5 = excitable), exit velocity (EV; m/sec) and temperament score [TS = (PS + EV)/2]. Bulls were electroejaculated every 2 wk beginning at a scrotal circumference of 24 cm through sexual maturity (i.e., 500,000,000 sperm/ejaculate). Within 7-21 d after reaching sexual maturity, bulls were fitted with jugular vein cannulas, and blood samples were collected at 15-min intervals for 6 h to determine the pattern of LH release. GnRH was then administered intravenously (10 ng/kg BW) and blood collection continued at 15-min intervals for an additional 8 h. Concentrations of LH in serum were determined by RIA. Amplitude of a detectable LH pulse, baseline concentration of LH, and area under the LH curve (AUC) were calculated for the 4-h period immediately preceding GnRH administration. Luteinizing hormone pulse incidence was evaluated using Pulse XP algorithm. The amplitude and height of the GnRH-induced LH release, AUC post-GnRH administration, and the duration of the GnRH-induced LH release were determined. Data were analyzed using a fixed effect model, with treatment and temperament classification included in the model. The occurrence of LH pulses during the pre-GnRH period was compared between treatment groups by chi-square analysis. More PNS bulls exhibited an LH pulse before GnRH injection (10 of 11; P < 0.01) than control bulls (3 of 12). No other characteristic associated with the release of LH during the pre-GnRH treatment evaluated in this study differed between groups (P > 0.1). All bulls responded similarly to exogenous GnRH, with the exception of the duration of the LH response which was greater (P = 0.02) in PNS bulls (268 ± 18 min) relative to control bulls (207 ± 16 min). Pattern of LH secretion before GnRH and duration of GnRH-induced LH release differed between PNS and control bulls. Stress during prenatal development may affect secretion of LH in sexually mature Brahman bulls. Keywords: Bulls, Prenatal Stress, LH
    2014 ADSA-ASAS-CSAS Joint Annual Meeting; 07/2014
  • Thomas H. Welsh, Nancy H Ing, Ronald D. Randel
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    ABSTRACT: Abstract Text: Environmental, physiological, psychological, and managerial stressors have been implicated as causes of reproductive disorders and decreased fertility in animals and humans. Herd reproductive efficiency and the stud industry depend upon the sperm producing capabilities and libido of bulls and stallions. With respect to male reproductive physiology, the steroidogenic and spermatogenic functions of the testis can be negatively impacted by stress-induced secretion of endogenous glucocorticosteroids (GC) as well as by treatment with exogenous GC agonists. The testes’ gametogenic function, a primary component of male fertility, is dependent upon appropriate transmission, receipt, and processing of specific endocrine signals. The deleterious effects of stress upon reproductive performance are presumably signaled by GC activation of the glucocorticoid receptor (NR3C1). Questions related to molecular mechanisms whereby stress affects specific components of the hypothalamic-pituitary-testicular (HPT) axis of male rodents, primates, cattle, sheep, pigs, horses and other species have been pursued by the use of in vitro and in vivo methods. This paper will provide a targeted overview of potential impacts of stressors upon the endocrine aspects of the HPT axis, with particular focus on direct testicular effects. Specific data to be presented are derived from studies of the influences of endogenous and exogenous GC on androgen biosynthesis and gene expression in testes of bulls and stallions. Chronic administration of a synthetic GC has been reported to increase the incidence of abnormal spermatozoa by direct action or perhaps by disruption of the endocrine or genetic mechanisms that support sperm production in bulls and stallions. Acute elevation of the systemic concentration of GC by pharmacologic methods or by mimicry of physiologic stress have inhibited testicular steroidogenesis and transiently decreased the systemic concentration of testosterone. The inhibitory action of endogenous GC concentrations on testicular steroidogenesis under stressed and non-stressed conditions indicates that activity of the hypothalamic-pituitary-adrenal axis may be of critical importance in establishment or maintenance of a functional HPT axis during prenatal, prepubertal, and postpubertal life. Homeostatic regulation of reproductive processes involves a physiological integration of the adrenal and testicular axes. The biologic and economic importance of deleterious influences of stress upon male reproductive processes dictate a thorough evaluation of adrenal–testicular interrelationships in domestic livestock species. Keywords: Stress; Steroidogenesis; Spermatogenesis
    2014 ADSA-ASAS-CSAS Joint Annual Meeting; 07/2014
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    ABSTRACT: Abstract Text: Eighteen Quarter Horses were utilized in a randomized complete design to evaluate age-related effects on inflammation and cartilage turnover after induction of a single inflammatory insult using lipopolysaccharide (LPS). Treatments consisted of age with yearlings (n = 3 males, n = 3 females), 2/3 yr olds (n = 2 males, n = 4 females), or mature 5 to 8 yr olds (n = 2 males, n = 4 females) for a 14 d experiment. For 14 d prior to the start of the experiment all horses were housed in individual stalls and fed diets that met or exceeded NRC (2007) requirements. On d 0, horses were challenged with an intra-articular injection of LPS. Radial carpal joints were randomly assigned to receive LPS using 0.5 ng LPS solution obtained from Escherichia coli O55:B5, or sterile lactated Ringer’s solution as a contralateral control. Synovial fluid was collected prior to LPS injection (0 h) and 6, 12, 24, 168, and 336 h post-injection. Samples were later analyzed using commercial ELISA kits for prostaglandin E2 (PGE2), collagenase cleavage neoepitope (C2C), and carboxypeptide of type II collagen (CPII). Rectal temperature (RT), heart rate (HR), and respiratory rate (RR) were monitored prior to sample collection over the first 24 h, and carpal circumference and joint surface temperature were recorded. Data were analyzed using PROC MIXED procedure of SAS. All values for RT, HR, and RR were within normal range and unaffected by treatment (P ≤ 0.21). Joint circumference was not influenced by treatment (P = 0.84), but circumference and surface temperature increased (P ≤ 0.01) across all treatments in response to intra-articular LPS. Synovial PGE2 levels were influenced by age with yearlings tending to have lesser (P = 0.09) values than 2/3 yr olds and mature horses. This was particularly evident at 12 h when PGE2 values peaked for all horses and yearlings had lesser values (P ≤ 0.01) than mature horses. Synovial C2C was influenced by treatment with yearlings and 2/3 yr olds having lesser (P ≤ 0.01) concentrations than mature horses. Synovial CPII was influenced by treatment at 24, 168 and 336 h with yearlings having lesser concentrations (P ≤ 0.01, P ≤ 0.06, and P ≤ 0.03, respectively) compared to 2/3 yr olds and mature horses. These results indicate that inflammation and corresponding cartilage turnover in response to LPS administration vary with age. Keywords: LPS, horse, synovial fluid, PGE2, CPII, C2C
    2014 ADSA-ASAS-CSAS Joint Annual Meeting; 07/2014
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    ABSTRACT: Abstract Text: The objective of this study was to determine if feeding of yeast cell wall (YCW) to pregnant cows influences cow performance as well as postnatal calf growth and immunity. Multiparous cows were assigned by predicted calving date into either the control (C; n=24) or supplemented (Y; n=24) groups. The Y cows were fed 4 g of YCW in 230 g of ground corn top-dressed on 1.81 kg of corn gluten and soybean meal (4:1) from approximately 90 d prepartum through 28 d postpartum. Weight and body condition score (BCS) were taken at 28-d intervals prepartum and postpartum. Within 24 hr of parturition, the BW and BCS of cows and BW of calves were recorded, and blood samples from calves were obtained to determine white blood cell numbers. These procedures were repeated on d 14 and 28 postpartum, and continued at 28-d intervals through weaning. Weaning weights were adjusted to 180 d of age. Cows were observed for estrus twice daily starting d 28 postpartum through first estrus. Data were analyzed using the MIXED procedure in SAS. Yeast supplementation did not affect cow prepartum BW (P=0.39) or BCS (P=0.14), postpartum BW (P=0.97) or BCS (P=0.89), or the postpartum interval (P=0.98; C=56.2±3.3, Y=56.3±3.2 d). Calf weight was not different at birth; however, on d 14 and at weaning, C males tended to be heavier than Y group males as well as females from the C and Y groups (P=0.08, 0.07, respectively). At d 28 C males were heavier than Y males or females (P=0.02). There was a tendency for 180-d adjusted weaning weight to be heavier for C males than either Y males or C and Y females (P=0.0563). There was also a treatment by day interaction in which C calves were heavier than Y calves (P=0.01) and a calf sex by day interaction with males being heavier than females preweaning (P=0.01). Treatment did not affect the white blood cell profile of calves on d 0 or 28 as C and Y calves had similar percentages (P > 0.2) of lymphocytes, monocytes, segmented neutrophils, banded neutrophils and eosinophils. The C males demonstrated a greater growth rate than prenatally supplemented calves in the neonatal and preweaning periods. These data suggest that prenatal YCW supplementation to healthy mature cows in a low stress environment does not benefit cow or calf performance. Keywords: yeast cell wall, calf performance, cow performance
    2014 ADSA-ASAS-CSAS Joint Annual Meeting; 07/2014
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    ABSTRACT: Abstract Text: Seventeen yearling Quarter horses were used in a randomized complete block design to evaluate potential of dietary CLA to mitigate intra-articular inflammation and cartilage metabolism following a single inflammatory insult. Horses were blocked by age, BW and sex and randomly assigned to treatment for a 56-day trial. Treatments consisted of a commercial concentrate offered at 1% BW (as fed) supplemented with either 1% soybean oil (CON; n=6), 0.5% soybean oil and 0.5% CLA (LOW; n=5; Lutalin®, BASF Corp.), or 1% CLA (HIGH; n=6; 55% purity) top-dressed daily. Horses were fed individually at 12 h intervals and offered 1% BW daily (as-fed) coastal bermudagrass (Cynodon dactylon) hay. On day 42, an LPS challenge was conducted. Carpal joints were randomly assigned to receive intra-articular injections of 0.5 ng LPS derived from Escherichia coli 055:B5 or sterile lactated Ringer’s solution as a contralateral control. Synovial fluid samples were taken via arthrocentesis at pre-injection h 0 and 6, 12, 24, 168 and 336 h post-injection, and were analyzed for prostaglandin E2 (PGE2), carboxypeptide of type II collagen (CPII), and collagenase cleavage neopeptide (C2C) using commercial ELISA kits. Vitals, including heart rate, rectal temperature and respiration rate were monitored at 0, 6, 12 and 24 h; and carpal circumference and surface temperatures were also recorded. Data were analyzed using PROC MIXED procedure of SAS. Vitals were not significantly different across treatments (P ≥ 0.13) and remained within normal ranges throughout the LPS challenge. Synovial PGE2 concentrations were not influenced by dietary treatment (P = 0.15). Synovial C2C concentrations were influenced by treatment (P = 0.05) with LOW and HIGH horses having lesser C2C than CON. Across all treatments C2C concentrations varied over time (P < 0.01) with values decreasing from 0 h to 6 h, peaking at 12 h and decreasing to 336 h. Levels of synovial CPII tended to be influenced by treatment (P =0.10) with LOW and HIGH horses having greater concentrations compared to CON. Regardless of diet, CPII concentrations increased over time (P < 0.01) with levels peaking at 24 h and decreasing to 336 h. In conclusion, CLA supplementation did not influence PGE2 concentrations following the LPS challenge; however, horses receiving CLA had lesser C2C and greater CPII concentrations, indicating less degradation and greater synthesis of cartilage in response to acute inflammation. Keywords: CLA, Synovial, LPS, Cartilage
    2014 ADSA-ASAS-CSAS Joint Annual Meeting; 07/2014
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    ABSTRACT: In rodents, livestock and primate species, a single dose of the synthetic glucocorticoid dexamethasone acutely lowers testosterone biosynthesis. To determine the mechanism of decreased testosterone biosynthesis, stallions were treated with 0.1mg/kg dexamethasone 12h prior to castration. Dexamethasone decreased serum concentrations of testosterone by 60% compared to saline-treated control stallions. Transcriptome analyses (microarrays, northern blots and quantitative PCR) of testes discovered that dexamethasone treatment decreased concentrations of glucocorticoid receptor alpha (NR3C1), alpha actinin 4 (ACTN4), luteinizing hormone receptor (LHCGR), squalene epoxidase (SQLE), 24-dehydrocholesterol reductase (DHCR24), glutathione S-transferase A3 (GSTA3) and aromatase (CYP19A1) mRNAs. Dexamethasone increased concentrations of NFkB inhibitor A (NFKBIA) mRNA in testes. SQLE, DHCR24 and GSTA3 mRNAs were predominantly expressed by Leydig cells. In man and livestock, the GSTA3 protein provides a major 3-ketosteroid isomerase activity: conversion of Δ(5)-androstenedione to Δ(4)-androstenedione, the immediate precursor of testosterone. Consistent with the decrease in GSTA3 mRNA, dexamethasone decreased the 3-ketosteroid isomerase activity in testicular extracts. In conclusion, dexamethasone acutely decreased the expression of genes involved in hormone signaling (NR3C1, ACTN4 and LHCGR), cholesterol synthesis (SQLE and DHCR24) and steroidogenesis (GSTA3 and CYP19A1) along with testosterone production. This is the first report of dexamethasone down-regulating expression of the GSTA3 gene and a very late step in testosterone biosynthesis. Elucidation of the molecular mechanisms involved may lead to new approaches to modulate androgen regulation of the physiology of humans and livestock in health and disease.
    The Journal of steroid biochemistry and molecular biology. 07/2014;
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    ABSTRACT: The objective of this study was to estimate the heritability of 3 measures of temperament in Brahman and Brahman-influenced calves (n = 1,209). Individual animal pen scores (PS) were determined by a trained observer who evaluated groups of 5 or 4 calves at a time for willingness to be approached by a human. Exit velocity (EV) was the rate (m/s) at which each calf exited a squeeze chute. Temperament score (TS) was calculated individually as (PS + EV)/2. Temperament was evaluated at 5 different times of record (28 d pre-weaning, weaning, 28 d post-weaning, 56 d post-weaning, and yearling). Contemporary groups (n = 34) were comprised of calves of the same sex born in the same season of the same yr. There were an average of 36 calves per contemporary group and group size ranged from 3 to 78 calves. Average weaning age (186 d) ranged from 105 to 304 d. Calves were born from 2002 through 2012. Random effects included additive genetic and the permanent environmental variance. The fixed effects analyzed were age of dam, sex of calf, contemporary group, fraction of Brahman (2 levels: 1 and 0.5), age of calf at record, and weaning age. At weaning, the mean PS was 2.68 ± 0.1, the mean EV was 2.41 ± 0.1, and the mean TS was 2.48 ± 0.1. The PS was affected by fraction of Brahman (P = 0.034) and tended to be affected by age of dam (P = 0.06). The EV was affected by contemporary group (P < 0.001) and tended to be affected by weaning age (P = 0.074). Contemporary group affected TS (P < 0.001). All 3 methods of temperament evaluation were affected by time of record (P < 0.001). The regression coefficients for PS, EV, and TS were 0.0023 ± 0.0014, 0.0022 ± 0.0012, and 0.0015 ± 0.0012 m⋅s(-1)⋅d(-1) of age, respectively. Estimates of maternal genetic effects were always 0 and omitted from final models. Estimates of heritability were 0.27 ± 0.1, 0.49 ± 0.1, and 0.43 ± 0.1 for EV, PS, and TS, respectively. Estimates of permanent environmental variances as proportions of phenotypic variance were 0.33 ± 0.1, 0.23 ± 0.1, and 0.33 ± 0.1 for EV, PS, and TS, respectively. There appears to be sufficient additive genetic variance for selective improvement of temperament characteristics in Brahman cattle.
    Journal of Animal Science 05/2014; · 2.09 Impact Factor
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    ABSTRACT: The influence of temperament on the alteration of metabolic parameters in response to a lipopolysaccharide(LPS) challenge was investigated. Brahman bulls were selected based on temperament score. Bulls (10 months; 211±5kg BW; n = 6, 8 and 7 for Calm, Intermediate and Temperamental groups, respectively) were fitted with indwelling jugular catheters to evaluate peripheral blood concentrations of glucose, blood urea nitrogen (BUN),non-esterified fatty acids (NEFA), insulin, epinephrine and cortisol before and after LPS administration (0.5 μg/kg BW LPS). Feed intake was also recorded. Intermediate bulls consumed more feed than the Temperamental bulls during the challenge (p = 0.046). Pre-LPS glucose (p = 0.401) and BUN (p = 0.222) did not differ among the temperament groups. However, pre-LPS insulin (p = 0.023) was lower, whereas pre-LPS NEFA (p < 0.001),cortisol (p < 0.001) and epinephrine (p < 0.001) were greater in Temperamental than in Calm and Intermediate bulls. Post-LPS glucose was increased in Calm and Intermediate bulls but not in Temperamental bulls(p < 0.001). Insulin concentrations post-LPS were greater in Calm than in Intermediate and Temperamental bulls (p < 0.001). Concentrations of NEFA post-LPS were greater in Temperamental than in Calm and Intermediate bulls (p < 0.001). Serum BUN concentration increased post-LPS, with values being greater in Calm and Intermediate than in Temperamental bulls (p = 0.012). Collectively, these data demonstrate that animal temperament is related to the metabolic responses of Brahman bulls following a provocative endotoxin challenge.Specifically, Temperamental bulls may preferentially utilize an alternate energy source (i.e. NEFA) to a greater degree than do bulls of Calm and Intermediate temperaments. The use of circulating NEFA from lipolysis may reduce the negative metabolic consequences of an immune response by allowing for a prompt answer to increasing energy demands required during immunological challenge, compared with the time required for glycogenolysis and gluconeogenesis.
    J Anim Physiol a Anim Nutr 02/2014; 98(1). · 1.25 Impact Factor
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    ABSTRACT: RF-amide related peptide 3 (RFRP3), the mammalian homologue of avian gonadotropin-inhibitory hormone (GnIH), has been shown to negatively regulate the secretion of LH and may contribute to reproductive seasonality in some species. Herein, we examined the presence and potential role of the RFRP3-signaling system in regulating LH secretion in the mare during the breeding and non-breeding seasons. Hypothalamic NPVF mRNA (the precursor mRNA for RFRP3) was detected at the level of the dorsomedial nucleus (DMH) and paraventricular nucleus (PVN), but expression did not change with season. A greater number of RFRP3-expressing cells was observed throughout the rostral-caudal extension of the DMH. Further, adenohypophyseal expression of the RFRP3 receptor (NPFFR1) during the winter anovulatory season did not differ from that during either the follicular or luteal phases of the estrous cycle. When tested in primary adenohyphyseal cell culture, or in vivo during both the breeding and non-breeding seasons, neither equine nor ovine peptide sequences for RFRP3 suppressed basal or GnRH-mediated release of LH. However, infusion of RF9, an RFRP3 receptor-signaling antagonist, into seasonally-anovulatory mares induced a robust increase in secretion of LH both before and following continuous treatment with GnRH. Results indicate that the cellular machinery associated with RFRP3 function is present in the equine hypothalamus and adenohypophysis. However, evidence for functionality of the RFRP3 signaling network was only obvious when an antagonist (RF9) was employed. As GnRH-induced release of LH was not affected by RF9, its actions may occur upstream from the gonadotrope to stimulate or disinhibit secretion of GnRH.
    Biology of Reproduction 01/2014; · 4.03 Impact Factor
  • Livestock Science 08/2013; 155(2-3):186-196. · 1.25 Impact Factor
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    ABSTRACT: Effective tick management on grazing animals is facilitated by accurate noninvasive detection methods. Fecal analysis provides information about animal health and nutrition. Diet affects fecal composition, stress may do likewise. The constituents in feces which may be affected by tick burdens and in turn affect near infrared spectra have not been reported. Our objective was to examine the interaction between plane of nutrition and tick burden on fecal composition in cattle. Angus cross steers (n = 28, 194 ± 3.0 kg) were assigned to one of four treatments (n = 7 per group) in a 2 x 2 factorial design: moderate (14.0 ± 1.0% CP, 60 ± 1.5% TDN) vs. low (9.0 ± 1.0% CP, 58 ± 1.5% TDN) plane of nutrition, and control (no tick) vs. tick treatment (infestation of 300 pair of adult Lone Star ticks [Amblyomma americanum] per treated animal). Fecal samples were collected at approximately 0700 h on d -7, 0, 7,10,14,17, and 21 relative to tick infestation. Fecal constituents measured were: DM, OM, pH, Lactobacillus spp., Escherchia coli, acetate, propionate, butyrate, isobutyrate, valerate, isovalerate, immunoglobulin A (IgA), and cortisol. Experimental d affected (P < 0.05). all constituents measured. Plane of nutrition affected (P < 0.05) DM, OM, VFAs, and IgA. Tick treatment numerically (P = 0.13) reduced cortisol. A multivariate stepwise selection model containing cortisol andE. Coli values on d 10 and d 14 accounted for 33% of the variation in daily adult female tick feeding counts across both planes of nutrition (P < 0.07). Within the moderate plane of nutrition, a model containing only cortisol on d 10 and d 14 described 59 % of the variation in the number of feeding ticks (P < 0.02). Similarly, a model including cortisol, propionate, isovalerate, and DM at d 10 and d 14 d described 95% of the variation in total feeding ticks in the low plane of nutrition. Of the constituents measured, fecal cortisol offers the best possibility of non-invasively assessing stress by way of a single assay but the presence of ticks would still need to be confirmed visually. Although several constituents measured in this study should exist in sufficient quantity to directly affect near infrared spectra, none stood out as a clear descriptor of prior observed differences in fecal spectra between tick-treated versus non tick-treated animals. There were, however, groups of fecal constituents related to daily adult female tick feeding numbers (as a visual estimation of tick stress).
    Journal of Animal Science 05/2013; · 2.09 Impact Factor
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    ABSTRACT: A decrease in fertility can have a negative economic impact, both locally and over a broader geographical scope, and this is especially the case with regard to the cattle industry. Therefore, much interest exists in evaluating proteins that might be able to increase the fertility of sperm. Heparin binding proteins (HBPs), specifically the fertility associated antigen (FAA) and the Type-2 tissue inhibitor of metalloproteinase (TIMP-2), act to favor the capacitation and acrosome reaction and perhaps even modulate the immune system's response toward the sperm. The objective of this research was to determine the effect on fertility of adding recombinant FAA (rFAA) and recombinant TIMP-2 (rTIMP-2) to bovine semen before cryopreservation for use in an artificial insemination (AI) program in a tropical environment. For this experiment, 100 crossbred (Bos taurus x Bos indicus) heifers were selected based on their estrus cycle, body condition score (BCS), of 4 to 6 on a scale of 1 to 9, and adequate anatomical conformation evaluated by pelvic and genital (normal) measurements. Heifers were synchronized using estradiol benzoate (EB), Celosil® (PGF2α) (Shering-Plough) and a controlled internal drug release (CIDR) device was inserted that contained progesterone. Inseminations were performed in two groups at random, 50 animals per group. The control group was inseminated with conventional semen. The treatment group was inseminated with semen containing rFAA (25 µg/mL) and rTIMP-2 (25 µg/mL). In the control group a 16% pregnancy rate was obtained versus a 40% pregnancy rate for the HBP treatment group, resulting in a significant difference (P = 0.0037). Given the results herein, one may conclude that the HBPs can increase fertility and could be an option for cattle in tropical conditions; however, one needs to consider the environment, nutrition, and the genetic interaction affecting the final result in whatever reproductive program that is implemented.
    PLoS ONE 01/2013; 8(6):e65083. · 3.53 Impact Factor
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    ABSTRACT: During early pregnancy in sheep, the elongating conceptus secretes interferon-τ (IFNT) and the conceptus as well as endometrial epithelia produce prostaglandins (PG) via PG synthase 2 (PTGS2) and cortisol via hydroxysteroid (11-β) dehydrogenase 1 (HSD11B1). Ovarian progesterone induces and PG and IFNT stimulates endometrial HSD11B1 expression and keto-reductase activity as well as many epithelial genes that govern trophectoderm proliferation, migration, and attachment during elongation. The primary aim of these studies was to test the hypothesis that HSD11B1-derived cortisol has a biological role in endometrial function and conceptus development during early pregnancy in sheep. In study 1, cyclic ewes received vehicle, cortisol, PF 915275 (PF; a selective inhibitor of HSD11B1), cortisol and PF, meloxicam (a selective inhibitor of PTGS2), cortisol and meloxicam, recombinant ovine IFNT, or IFNT and PF into the uterus from day 10 to day14 after estrus. Cortisol and IFNT stimulated endometrial HSD11B1 expression and activity, increased endometrial PTGS2 activity and the amount of PG in the uterine lumen, and up-regulated many conceptus elongation-related genes in the endometrium. Some effects of cortisol and IFNT were mediated by PTGS2-derived PG. In study 2, bred ewes received PF 915275 or recombinant ovine IFNT and into the uterus from day 10 to day 14 after mating. Inhibition of HSD11B1 activity in utero prevented conceptus elongation, whereas IFNT rescued conceptus elongation in PF-infused ewes. These results suggest that HSD11B1-derived cortisol mediates, in part, actions of ovarian progesterone and the conceptus on endometrial function and support the hypothesis that IFNT, PG, and cortisol coordinately regulate endometrial functions important for conceptus elongation and implantation during early pregnancy in sheep.
    Endocrinology 12/2012; · 4.72 Impact Factor
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    ABSTRACT: This study was designed to characterize potential sexually dimorphic stress and immunological responses following a corticotropin-releasing hormone (CRH) challenge in beef cattle. Six female (heifers) and six male (bulls) Brahman calves (264 ± 12 d of age) were administered CRH intravenously (0.5 µg of CRH/kg body mass) after which serum concentrations of cortisol increased from 0.5 h to 4 h. From 1 h to 4 h after CRH administration, serum cortisol concentrations were greater in heifers than in bulls. In all cattle, increased serum concentrations of TNF-α, IL-6 and IFN-γ were observed from 2.5 h to 3 h after CRH, with greater concentrations of IFN-γ and IL-6 in heifers than bulls. Heifer total leukocyte counts decreased 1 h after CRH administration, while bull leukocyte counts and percent neutrophils decreased 2 h after CRH administration. Heifers had greater rectal temperatures than bulls, yet rectal temperatures did not change following administration of CRH. There was no effect of CRH administration on heart rate. However, bulls tended to have increased heart rate 2 h after CRH administration than before CRH. Heifer heart rate was greater than bulls throughout the study. These data demonstrate that acute CRH administration can elicit a pro-inflammatory response, and cattle exhibit a sexually dimorphic pro-inflammatory cytokine and cortisol response to acute CRH administration.
    Innate Immunity 10/2012; · 2.68 Impact Factor
  • R D Randel, T H Welsh
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    ABSTRACT: The influence of nutrition on puberty in beef heifers is complex and under neuroendocrine control. The stores of body fat in mammals are a determinant of the onset and maintenance of puberty. Body fat stores are greater in heifers with greater residual feed intake than in their more efficient herdmates. A one unit increase in residual feed intake resulted in a reduction of 7.54 d in age at puberty in Bos taurus beef heifers. However, Bos indicus-influenced heifers, which reach puberty at older ages, were not found to have sexual maturity influenced by selection for residual feed intake. The strong influence of body fat stores on return to estrus after calving does indicate that selection for leaner beef heifers could affect reproductive performance relative to puberty and postpartum rebreeding of first calf heifers. The influence of intermediary metabolism, through signals at the central nervous system, regulates the GnRH pulse generator, thereby influencing pituitary and ovarian function culminating with puberty and return to ovarian cydicity following calving. Tropically adapted cattle (i.e., Santa Gertrudis and Brahman) selected for low residual feed intake had a lesser response of insulin to a glucose challenge than their less efficient herdmates. These studies indicate the possibility that animals with differing residual feed intake (efficiencies) may have differing intermediary metabolism and, therefore, differing rates of reaching puberty. Selection for low residual feed intake results in selection of leaner heifers that reach puberty at older ages. These leaner heifers calve later in their first and subsequent calving seasons. Selection for residual average daily gain has no negative influence on age at puberty or calving interval. Selection for residual average daily gain may be an acceptable method to improve feed efficiency without harming reproductive efficiency.
    Journal of Animal Science 10/2012; · 2.09 Impact Factor

Publication Stats

1k Citations
255.50 Total Impact Points

Institutions

  • 1990–2014
    • Texas A&M University
      • • Department of Animal Science
      • • Department of Large Animal Clinical Sciences
      • • Department of Veterinary Integrative Biosciences
      • • Department of Psychology
      • • Faculty of Toxicology
      College Station, Texas, United States
  • 2012
    • Texas Tech University
      Lubbock, Texas, United States
  • 2011–2012
    • Washington State University
      • Department of Animal Sciences
      Pullman, WA, United States
    • Honolulu University
      Honolulu, Hawaii, United States
  • 2007–2012
    • Agricultural Research Service
      Kerrville, Texas, United States
  • 1995–2011
    • Texas A&M University System
      College Station, Texas, United States
  • 2009–2010
    • Texas A&M University - Kingsville
      Kingsville, Texas, United States
  • 1994–2006
    • Connecticut Agricultural Experiment Station
      New Haven, Connecticut, United States
  • 1997
    • United States Department of Agriculture
      • Agricultural Research Service (ARS)
      Washington, D. C., DC, United States
  • 1996
    • University of Hawaiʻi at Mānoa
      • Department of Human Nutrition, Food and Animal Sciences
      Honolulu, HI, United States
  • 1981
    • North Carolina State University
      • Department of Animal Science
      Raleigh, North Carolina, United States