Date of Award

12-2017

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Animal and Veterinary Sciences

Committee Member

Scott L. Pratt, Committee Chair

Committee Member

Dr. John Mueller

Committee Member

Dr. John Andrae

Abstract

The objective of this study was to evaluate the growth and reproductive development of young growing beef bulls on a complete forage ration (F) to development of similar young growing beef bulls on a forage ration supplemented with concentrate (CT). Data was collected from the 665 beef bulls, grouped into breed codes (BC) of continental (CN; n = 103) or British (B; n = 562) that participated in the Edisto Forage Bull Test (EFBT) in Blackville, SC from 2006 to 2016 with the exception of 2012. Data from 2012 was lost in a clerical mishap. All Angus, red Angus, and Hereford were classified as British, and all Gelbvieh/Gelbvieh influence, Simmental/Simmental influence, Charolais, and Limousin/Limousin influence were classified as CN. Bulls were tested under two different management systems (MS). The MS from 2006 to 2010 was the CT the bulls a forage ration supplemented with a concentrate at 1% of body weight. From 2011 to 2016 bulls were subjected to an all the F ration. Across all years, the EFBT bulls were weighed as they came on test, and then every 28 days until the final weigh day on day 168 of the test. Variables analyzed were, body weight (BW), scrotal circumference (SC), average daily gain (ADG), Test average daily gain (TADG), weight per day of age at test day 168 (WDA d168), and frame score (FS) at the on test point. Bulls were subjected to a breeding soundness exam prior 332 days after the start of the test, ±21 days before the sale date. The data set did not include Bos Indicus bulls or bulls (<50 head) where data was missing or did not finish the test due to illness, injury or death. Data were subjected to LS means with MS, BC, period and their interactions as the main effects with differences determined using Students t-test. Chi-square analysis was utilized to evaluate the breeding soundness data. Generally the study found MS had an effect on BW, ADG, and SC (P<0.05). In the case SC the effect of MS was present at d112 (P<0.05) but had lost any effect by d332.

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