Murray State Theses and Dissertations


Anthelmintic treatment is known to improve cattle performance; however, effects of long-acting eprinomectin (LAE) and co-treatment (Co-Trt) use has not been widely evaluated. Lactate dehydrogenase is an important cytoplasmic enzyme which can serve as an indicator of cellular damage but little information is available regarding differences in activity of calves receiving various anthelmintics. Therefore, the objective of this study was to evaluate the effects of various anthelmintic treatments on fecal egg counts (FEC), performance, blood parameters, and lactate dehydrogenase (LDH) activity of newly received stocker calves. This study consisted of 125 Angus based cross bred steers grazed during summer months of 2016 (Exp 1) and 2017 (Exp 2). Anthelmintic treatments consisted of: Control (CON), long-acting eprinomectin (LAE), dual oxfendazole and moxidectin administration (COMBO), and oxfendazole on d 0 followed by delayed moxidectin on d 45 (O+M). Fecal samples were recorded and body weight (BW), body condition scores (BCS), hair coat scores (HCS), and fly counts determined. Jugular blood was collected for determination of complete blood cell count data and serum lactate dehydrogenase activity. Data was analyzed using the MIXED procedure of SAS with preplanned orthogonal contrasts used. Body weight tended (P=0.09) to be greater for LAE versus Co-Trt steers in Exp 2. Greater BCS (P<0.01) were observed for O+M versus COMBO steers in Exp 2 and tended to be greater for LAE versus Co-Trt steers by the end of the study. Average daily gain was affected by treatment at various points throughout the study but were similar (P=0.86) between LAE and O+M steers overall during Exp 2. During both Exp, COMBO steers exhibited a lesser degree of shedding compared to other treatments. Fly counts were not affected by treatment in either Exp but were affected by d (P<0.01). A treatment by day interaction (P < 0.01) was observed in Exp 2 for RBC with effects of d (P<0.01) being observed for several blood parameters. Eosinophils were higher (P=0.03) in LAE versus COMBO steers in Exp 1. Serum LDH activity was lowest in O+M steers and differed (P=0.01) from values observed in COMBO steers suggesting that oxidative stress may have occurred in the COMBO treated steers. Data suggests anthelmintic use can reduce FEC and may improve performance and that delayed that versus dual Co-Trt anthelmintic administration may be beneficial. Furthermore, differences may exist in LDH activity in stocker calves treated with various anthelmintics.

Year manuscript completed


Year degree awarded


Author's Keywords

Anthelmintic, bovine, lactate dehydrogenase

Thesis Advisor

Amanda Davis

Committee Chair

Amanda Davis

Committee Member

Elizabeth Backes

Committee Member

William DeWees

Committee Member

Cheryl Porr

Committee Member

Alyx Shultz

Document Type


Included in

Beef Science Commons