Abstract #M67

# M67
Plasma cholesterol and show-ring success of cholesterol deficiency carriers.
B. L. Basiel*1, A. L. Macrina1, C. D. Dechow1, 1The Pennsylvania State University, State College, PA.

Cholesterol deficiency (CD) in Holstein cattle results from an insertion in the APOB gene which traces to the bull Maughlin Storm. Calves that are homozygous for CD cannot transport cholesterol and perish before 6 mo of age. The mutation may have a partially dominant effect with lowered cholesterol in heterozygous animals. Our aims were to evaluate plasma cholesterol in heterozygous animals and to determine if CD carrier status is associated with show ring success. Blood was collected from 26 genotyped Holsteins in the Penn State dairy herd and included 12 CD carriers and 14 non-carriers. Plasma samples were analyzed for cholesterol concentration (mg/dL) using mixed models that included linear and quadratic effects of DIM. Additionally, CD carrier status of cows placing in the top 5 and top 10 in cow classes at World Dairy Expo that were sired by known CD carriers was compiled. From 2006 to 2018 there were 199 instances of 119 cows with genotypic data available and sired by a CD carrier sire placing in the top 10; of those, 114 were CD carriers and 85 were non-carriers. There were 117 instances from 75 cows for top 5 placings. Chi-squared tests for equal proportions were evaluated to determine if the following were associated with CD status: placing in the top 10 with cows allowed to contribute multiple years, placing in the top 5 with cows allowed to contribute multiple years, top 10 cows only considering individuals once, and top 5 cows only considering individuals once. There was a trend (P = 0.09) for non-carriers to have higher plasma cholesterol (155 mg/dL) than CD carriers (137 mg/dL). Further, there were significantly (P < 0.05) more CD carriers in the top 5 and 10 of classes at World Dairy Expo when cows were considered over multiple years; there was a trend (P = 0.08) for placement in the top 5 cows when individuals were only considered once. This data indicates that plasma cholesterol levels may be reduced in CD carriers but should be validated with a larger sample size. Moreover, reasons for an apparent advantage of CD carriers over non-carrier siblings at an elite cattle show warrants further investigation.

Key Words: cholesterol deficiency, show, cholesterol