Meat Animal Research Center

Clay Center, NE, United States

Meat Animal Research Center

Clay Center, NE, United States
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Canovas A.,University of California at Davis | Reverter A.,CSIRO | DeAtley K.L.,New Mexico State University | DeAtley K.L.,California State University, Chico | And 12 more authors.
PLoS ONE | Year: 2014

Puberty is a complex physiological event by which animals mature into an adult capable of sexual reproduction. In order to enhance our understanding of the genes and regulatory pathways and networks involved in puberty, we characterized the transcriptome of five reproductive tissues (i.e. hypothalamus, pituitary gland, ovary, uterus, and endometrium) as well as tissues known to be relevant to growth and metabolism needed to achieve puberty (i.e., longissimus dorsi muscle, adipose, and liver). These tissues were collected from pre- and post-pubertal Brangus heifers (3/8 Brahman; Bos indicus x 5/8 Angus; Bos taurus) derived from a population of cattle used to identify quantitative trait loci associated with fertility traits (i.e., age of first observed corpus luteum (ACL), first service conception (FSC), and heifer pregnancy (HPG)). In order to exploit the power of complementary omics analyses, pre- and post-puberty co-expression gene networks were constructed by combining the results from genome-wide association studies (GWAS), RNA-Seq, and bovine transcription factors. Eight tissues among pre-pubertal and post-pubertal Brangus heifers revealed 1,515 differentially expressed and 943 tissue-specific genes within the 17,832 genes confirmed by RNA-Seq analysis. The hypothalamus experienced the most notable upregulation of genes via puberty (i.e., 204 out of 275 genes). Combining the results of GWAS and RNA-Seq, we identified 25 loci containing a single nucleotide polymorphism (SNP) associated with ACL, FSC, and (or) HPG. Seventeen of these SNP were within a gene and 13 of the genes were expressed in uterus or endometrium. Multi-tissue omics analyses revealed 2,450 co-expressed genes relative to puberty. The pre-pubertal network had 372,861 connections whereas the postpubertal network had 328,357 connections. A sub-network from this process revealed key transcriptional regulators (i.e., PITX2, FOXA1, DACH2, PROP1, SIX6, etc.). Results from these multi-tissue omics analyses improve understanding of the number of genes and their complex interactions for puberty in cattle.

Huson H.J.,Cornell University | Huson H.J.,U.S. Department of Agriculture | Kim E.-S.,U.S. Department of Agriculture | Kim E.-S.,Iowa State University | And 9 more authors.
Frontiers in Genetics | Year: 2014

The slick hair coat (SLICK) is a dominantly inherited trait typically associated with tropically adapted cattle that are from Criollo descent through Spanish colonization of cattle into the New World. The trait is of interest relative to climate change, due to its association with improved thermo-tolerance and subsequent increased productivity. Previous studies localized the SLICK locus to a 4 cM region on chromosome (BTA) 20 and identified signatures of selection in this region derived from Senepol cattle. The current study compares three slick-haired Criollo-derived breeds including Senepol, Carora, and Romosinuano and three additional slick-haired cross-bred lineages to non-slick ancestral breeds. Genome-wide association (GWA), haplotype analysis, signatures of selection, runs of homozygosity (ROH), and identity by state (IBS) calculations were used to identify a 0.8 Mb (37.7-38.5 Mb) consensus region for the SLICK locus on BTA20 in which contains SKP2 and SPEF2 as possible candidate genes. Three specific haplotype patterns are identified in slick individuals, all with zero frequency in non-slick individuals. Admixture analysis identified common genetic patterns between the three slick breeds at the SLICK locus. Principal component analysis (PCA) and admixture results show Senepol and Romosinuano sharing a higher degree of genetic similarity to one another with a much lesser degree of similarity to Carora. Variation in GWA, haplotype analysis, and IBS calculations with accompanying population structure information supports potentially two mutations, one common to Senepol and Romosinuano and another in Carora, effecting genes contained within our refined location for the SLICK locus. © 2014 Huson, Kim, Godfrey, Olson, McClure, Chase, Rizzi, O'Brien, Van Tassell, Garcia and Sonstegard.

Klotz J.L.,U.S. Department of Agriculture | Aiken G.E.,U.S. Department of Agriculture | Bussard J.R.,University of Kentucky | Foote A.P.,University of Kentucky | And 6 more authors.
Toxins | Year: 2016

Previous research has indicated that serotonergic and α-adrenergic receptors in peripheral vasculature are affected by exposure of cattle grazing toxic endophyte-infected (E+; Epichlöe coenophialia) tall fescue (Lolium arundinaceum). The objective of this experiment was to determine the period of time necessary for the vascular effects of ergot alkaloids to subside. Two experiments were conducted to investigate changes in vascular contractile response and vasoconstriction over time relative to removal from an ergot alkaloid-containing E+ tall fescue pasture. In Experiment 1, lateral saphenous vein biopsies were conducted on 21 predominantly Angus steers (357 ± 3 kg body weight) at 0 (n = 6), 7 (n = 6), 14 (n = 5), or 28 days (n = 4) after removal from grazing pasture (3.0 ha; endpoint ergovaline + ergovalinine = 1.35 mg/kg DM) for 126 days. In Experiment 2, lateral saphenous veins were biopsied from 24 Angus-cross steers (361 ± 4 kg body weight) at 0, 21, 42, and 63 days (n = 6 per time point) following removal from grazing tall fescue pastures (3.0 ha; first 88 days endpoint ergovaline + ergovalinine = 0.15 mg/kg DM; last 18 days endpoint ergovaline + ergovalinine = 0.57 mg/kg DM) for 106 total days. Six steers (370 ± 18 kg body weight) off of bermudagrass pasture for the same time interval were also biopsied on Day 0 and Day 63 (n = 3 per time point). Additionally, in Experiment 2, cross-sectional ultrasound scans of caudal artery at the fourth coccygeal vertebra were taken on Days 0, 8, 15, 21, 29, 36, 42, and 45 to determine mean artery luminal area to evaluate vasoconstriction. In both experiments, steers were removed from pasture and housed in a dry lot and fed a corn silage diet for the duration of biopsies and ultrasound scans. Biopsied vessels used to evaluate vasoactivity were cleaned, incubated in a multimyograph, and exposed to increasing concentrations of 4-Bromo-3,6-dimethoxybenzocyclobuten-1-yl) methylamine hydrobromide (TCB2; 5HT2A agonist), guanfacine (GF; α2A-adrenergic agonist), and (R)-(+)-m-nitrobiphenyline oxalate (NBP; α2C-adrenergic agonist) in both experiments and ergovaline (ERV) and ergotamine (ERT) in Experiments 1 and 2, respectively. In Experiment 1, days off pasture × agonist concentration was not significant (p > 0.1) for all four compounds tested. In Experiment 2, GF, NBP, TCB2 and ERT were significant for days off pasture × agonist concentration interaction (p < 0.02) and vasoactivity increased over time. Vasoactivity to agonists was reduced (p < 0.05) when steers were initially removed from E+ tall fescue pasture compared to bermudagrass, but did not differ by Day 63 for any variable. Luminal areas of caudal arteries in steers grazed on E+ tall fescue relaxed and were similar to steers that had grazed bermudagrass for 36 days on non-toxic diet (p = 0.15). These data demonstrate changes in peripheral vasoactivity and recovery from vasoconstriction occur beyond five weeks off toxic pasture and 5HT2A receptors appear to be more dramatically affected in the lateral saphenous vein by grazing E+ tall fescue pasture than adrenergic receptors. © 2016 by the authors; licensee MDPI, Basel, Switzerland.

Spiehs M.J.,U.S. Department of Agriculture | Brown-Brandl T.M.,Meat Animal Research Center | Miller D.N.,U.S. Department of Agriculture | Parker D.B.,West Texas A&M University
American Society of Agricultural and Biological Engineers Annual International Meeting 2012, ASABE 2012 | Year: 2012

Bedding materials may affect air quality in livestock facilities. The objective of this study was to compare headspace concentrations of odorous volatile organic compounds (VOCs), ammonia (NH3), carbon dioxide (CO2),methane (CH4), and nitrous oxide (N2O) when pine wood chips (PC) and corn stover (CS) were mixed in various ratios (0, 10, 20, 30, 40, 60, 80, and 100% PC) and used as bedding in lab-scaled bedded manure packs. Odor activity values (OAV) were calculated using VOC concentration. Air samples were collected from the headspace of the lab-scaled bedded packs weekly for 6 weeks. Concentration of VOC was similar among all bedding treatments (P ≥ 0.30), as were the OAV. Ammonia concentration increased linearly with increasing inclusion of PC in the bedding mix (P = 0.002; R2 = 0.5819). Carbon dioxide, CH4, and N2O concentrations were similar among bedding materials (P ≥ 0.61) and changed throughout the 6 week study (P < 0.01). Results of this study indicate that mixtures of bedding material containing > 60% PC may increase NH3, but VOC, greenhouse gas production, and odor potential as indicated by OAV will not be affected by the inclusion of PC when used in deep-bedded livestock facilities.

Jones D.,University of Nebraska - Lincoln | Brown-Brandl T.M.,Meat Animal Research Center
Precision Livestock Farming 2013 - Papers Presented at the 6th European Conference on Precision Livestock Farming, ECPLF 2013 | Year: 2013

Heat stress in feedlot cattle is a concern. A study was conducted to characterize heat stress in feedlot cattle and to determine the impact of providing shade. To characterize the response to heat stress, linear equations were developed for each of 384 heifers relating 8 different indicators. In unshaded feedlot cattle, it was determined that the lower categories of responsiveness had more lighter colored breeds and the higher categories of responsiveness had more darker colored breeds of cattle. However, it was noted that there were lighter colored animals with high responsiveness and darker breeds with low responsiveness.

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