Browsing by Author "Petry, Amy L. (TTU)"
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Item Effects of feedlot bunk management and bulk density of steam-flaked corn on growth performance, carcass characteristics, and liver score of finishing beef steers fed high-concentrate diets without by-products or tylosin phosphate(2021) Smock, Taylor M. (TTU); Woerner, Dale R. (TTU); Petry, Amy L. (TTU); Manahan, Jeff L. (TTU); Helmuth, Cory L. (TTU); Coppin, Carley M. (TTU); Hales, Kristin E. (TTU)Objective: Our objective was to evaluate effects of bunk management strategy and bulk density of steam-flaked corn (SFC) on growth performance, carcass characteristics, and incidence and severity of liver abscesses in finishing beef steers fed diets without tylosin phosphate. Materials and Methods: Beef steers (n = 192; initial BW = 332 ± 8.1 kg) were used in a randomized complete block design comprised of 12 BW blocks and 12 pen replications per treatment. A 2 × 2 factorial arrangement of treatments was used: (1) slick-bunk management + 335 g/L SFC-based diets (SFC); (2) modified ad libitum bunk management + 335 g/L SFC; (3) slick-bunk management + 425 g/L SFC; (4) modified ad libitum bunk management + 425 g/L SFC. Results and Discussion: Bunk management strategy did not affect growth performance, carcass characteristics, or liver abscess score (P ≥ 0.10). The ADG of steers fed 425 g/L SFC was greater (P = 0.05) from d 35 to 105 than those fed 335 g/L SFC; however, overall ADG was not different (P = 0.36). The DMI of steers fed 425 g/L SFC was greater at each interim period (P ≤ 0.05) and overall (P ≤ 0.01) than those fed 335 g/L SFC. Gain-to-feed (G:F) of steers fed 425 g/L SFC tended (P = 0.10) to be lesser from d 0 to 35 but was not different overall (P = 0.12). Steers fed 425 g/L SFC tended to have greater backfat and calculated empty body fat percentage (P ≤ 0.07) than those fed 335 g/L SFC and greater calculated YG (P = 0.05). Steers fed 425 g/L SFC had 43.5% fewer (P = 0.04) liver abscesses than those fed 335 g/L SFC, but liver abscess severity did not differ (P ≥ 0.12). Implications and Applications: Bunk management did not affect growth performance, carcass characteristics, or development of liver abscesses. Steers fed 425 g/L SFC-based diets had greater DMI and 43.5% fewer liver abscesses than those fed 335 g/L SFC-based diets with similar overall G:F, but carcasses were fatter. Greater bulk density of SFC may be a useful management strategy and a viable antimicrobial alternative to decrease liver abscesses.Item Ewe Vaginal Microbiota: Associations With Pregnancy Outcome and Changes During Gestation(2021) Koester, Lucas R.; Petry, Amy L. (TTU); Youngs, Curtis R.; Schmitz-Esser, StephanReproductive performance is paramount to the success of livestock production enterprises focused on lamb meat production. Reproductive success is influenced by various factors, possibly including the reproductive tract microbial communities present at the time of copulation and throughout pregnancy. There are few publications that identify the vaginal microbial communities of livestock, and even fewer exist for sheep. To compare ewe vaginal microbial communities, vaginal swabs were taken from 67 Hampshire and Hampshire X Suffolk crossbred ewes from the Iowa State University sheep farm at a pre-breeding time point (S1) and after pregnancy testing (S2). Animals that were determined pregnant were sampled again within a few days of expected parturition (S3). DNA was extracted from these swabs, and 16S rRNA gene Illumina MiSeq amplicon sequencing was conducted to fingerprint the bacterial communities found within this system. Pre-breeding time point samples showed no differences in community structure between animals later found to be pregnant or non-pregnant, but significant changes were detected in species richness (Chao; P < 0.001) and species diversity (Shannon; P < 0.001) at the second sampling time point. A higher microbial diversity within the S2 time point samples may suggest a more stable environment driven by pregnancy, as this increased diversity is maintained in pregnant animals from the S2 to the S3 time point. Additionally, several bacterial phylotypes, such as Mannheimia, Oscillospiraceae-like OTUs and Alistipes, were more abundant at either the S1 or S2 time points in animals that established pregnancy, suggesting a beneficial effect on pregnancy outcome. This study identifies changes within the microbial communities of the ewe vagina before and during gestation and offers inferences on how these changes may impact pregnancy outcome. Information presented herein offers new knowledge about sheep vaginal microbial communities and serves as a starting point to help guide researchers to improve sheep reproductive performance in the future.