Browsing by Author "Perz, Katharine A."

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Feed efficiency phenotypes in lambs involve changes in ruminal, colonic, and small-intestine-located microbiota
(2017-06) Perea, K.; Perz, Katharine A.; Olivo, Sarah K.; Williams, Andrew F.; Lachman, Medora M.; Ishaq, Suzanne L.; Thomson, Jennifer M.; Yeoman, Carl J.
Several studies have revealed differences in rumen-located microbes between greatly efficient and inefficient animals; however, how the microbiota vary in the hind gastrointestinal tract (GIT) has only been sparsely explored and how they vary in the small intestine remains to be determined. We therefore sampled the microbiota of the duodenum, jejunum, ileum, colon, and colorectally-obtained feces, in addition to the rumen of 12 lambs that, in a residual feed intake trial, were found to be at either extreme of feed efficiency phenotypes. The 16S rRNA gene (V3-V4 region) profiles of all samples were analyzed and revealed unique microbiota in all GIT locations except the jejunum and ileum (ANOSIM R > 0.2, P < 0.001). Measures of beta-diversity revealed greater dissimilarity between more anatomically distant GIT locations (e.g., Rumen-Duodenum, ANOSIM R = 0.365, P < 0.001; Rumen-Colon, ANOSIM R = 1, P < 0.001) with the nearest distal region typically more similar than the nearest proximal location. The relative abundances of 13 operational taxonomic units (OTUs) from the duodenum, jejunum, colon, and feces, as well as the rumen, differed between efficient and inefficient animals (Bonferroni corrected, P < 0.05), while another 2 OTUs trended toward significance. These OTUs were classified as taxa with known roles in fibrolysis (Fibrobacteres, Ruminococcaceae, and Saccharofermentans) and others that are commonly associated with health (Bifidobacteriaceae, and Christensenellaceae) and dysbiosis (Proteobacteria). Our findings show biospatial delineations of microbiota throughout the GIT and suggest that feed efficiency extends beyond the rumen, transcending these regions, and involves increases in both rumen-and colon-located fibrolytic taxa, increases in bifidobacterial species in the small intestine, and reductions in small intestine and distal GIT-located Proteobacteria.
The use of blood lactate concentration as an indicator of temperament and its impact on growth rate and tenderness of steaks from Simmental-Angus steers
(2015-05) Boles, Jane A.; Kohlbeck, Katelyn S.; Meyers, M. C.; Perz, Katharine A.; Davis, K. C.; Thomson, Jennifer M.
Abstract The objective of this study was to evaluate the use of blood lactate concentration as an objective measure of beef cattle temperament and determine if the temperament of steers affected growth rate and tenderness of beef steaks. Angus × Simmental steers (n = 154) were evaluated for blood lactate (BL), exit velocity (EV) and chute score (CS), and humanely harvested. Carcass characteristics were assessed and loin samples were obtained for tenderness evaluation. All measures of the temperament were significantly correlated to each other (r = 0.14–0.47; P ≤ 0.04). Steaks from steers in the medium BL classification were significantly more tender than steaks from steers from the high BL classification. The steers with faster EV tended to result in steaks with higher shear force values (P = 0.07). The steers classified as fast growing resulted in steaks with lower shear force values (P = 0.02) compared to steaks from steers classified as slow growing. Results suggest that the temperament contributes to variations in growth rate, blood lactate, and tenderness.