Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Animal Science (PhD)

Degree Level



Animal Science


Jeremy G. Powell

Committee Member

Elizabeth B. Kegley

Second Committee Member

Thomas A. Yazwinski

Third Committee Member

Kelly M. Loftin


Biological sciences, Long-acting eprinomectin, Moxidectin, Oxfendazole, Performance, Replacement heifers, Spring-calving cows


Experiment 1, 83, newly weaned, fall-born crossbred heifer calves were allocated randomly to 1 of 3 anthelmintic treatments: 1) control (CON); 2) combination pour-on moxidectin and oxfendazole (MO); and 3) long-acting eprinomectin (LAE). Two preplanned orthogonal contrast statements were used: 1) to compare CON to treated cattle; and 2) to compare OXF to LAE. Heifer BW and BCS were greater (P≤0.02) from MO and LAE on d 112, 140, 154, 168, 182 compared to CON. Heifer cyclicity, estrous detection, natural service and overall pregnancy rates were greater (P≤0.02) for MO and LAE compared to CON. Cattle fecal egg counts (FEC) were greater (P0.20) between CON and treated cows. Day 14 BCS tended (P=0.07) to be greater for CON compared to treated cows. Also, BCS was greater (P=0.01) and hair coat score was lower (P