Date of Graduation

12-2019

Document Type

Thesis

Degree Name

Master of Science in Animal Science (MS)

Degree Level

Graduate

Department

Animal Science

Advisor/Mentor

Powell, Jeremy G.

Committee Member

Rosenkrans, Charles F. Jr.

Second Committee Member

Kutz, Bryan

Keywords

Animal Breeding; Beef Cattle Performance; Beef Cattle Production; Genetics

Abstract

Foot soundness and udder conformation are essential for longevity in beef cattle. The objective of this study was to investigate the effects of foot angle (FA), claw set (CS), teat size (TS) and udder suspension (US) scores on cowherd performance. Data were analyzed for 1,685 observations on Angus-based cows over a four-year period. At weaning FA, CS, TS, and US were evaluated. Scores are based on nine-point scales. A score of one indicates straight pasterns, divergent toes, enlarged bottle shaped teats, and absence of a median suspensory ligament; nine indicates weak pasterns, curled toes, small symmetrical teats, and a tight udder attachment. Cows that exhibited FA and CS scores from four to six were considered acceptable. Cows that exhibited scores outside this range were considered undesirable. Cattle with US and TS scores ranging between four and eight were evaluated. All cows were evaluated for age and performance traits including pre-breeding weight (PBW), pre-breeding body condition score (PBCS), pregnancy rate, calf birthweight (BW), calf weaning weight (WW), calf adjusted weaning weight (AWW), cow body weight at weaning (CWW), weaning body condition score (WBCS), and adjusted weaning performance (AWP). Data were analyzed using the GLIMMIX procedure of SAS. Significance was declared at P ≤ 0.05. Acceptable cows had a WBCS 10.14% greater (P < 0.01) compared to undesirable cows. Acceptable cows possessed an average WBCS of 4.83 compared to 4.34 in undesirable cows. Acceptable cows were 9.50% younger (P = 0.05) than undesirable cows. The mean age for acceptable cows was 4.67 compared to 5.16 in undesirable cows. There were no US differences (P ≥ 0.24) for WBCS. There were no TS differences (P ≥ 0.13) for CWW, WBCS, WW, AWW, and AWP. Cattle with US scores of 4 were on average the oldest (P < 0.01) at 7.75 years of age. Cattle with TS scores of 8 were on average the youngest (P < 0.01) at 3.20 years of age. Cattle with US scores of 4 weaned the heaviest calves (P < 0.01) at 246.92 kg. These results could help predict cow performance based on FA, CS, TS, and US.

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