Effects of extended-release eprinomectin on productivity measures in cow-calf systems and subsequent feedlot performance and carcass characteristics of calves

Effects of extended-release eprinomectin on productivity measures in cow-calf systems and subsequent feedlot performance and carcass characteristics of calves Claire Andresen 0 1 2 Iowa State University 0 1 2 0 1 2 Dan Loy 0 1 2 Iowa State University 0 1 2 0 1 2 0 This Beef is brought to you for free and open access by the Animal Science Research Reports at Iowa State University Digital Repository. It has been accepted for inclusion in Animal Industry Report by an authorized editor of Iowa State University Digital Repository. For more information , please contact , USA 1 Iowa State University , USA 2 Andresen , Claire; Loy, Dan; Gunn, Patrick; and Brick, Troy (2018) "Effects of extended-release eprinomectin Follow this and additional works at: https://lib.dr.iastate.edu/ans_air Part of the Agriculture Commons, and the Animal Sciences Commons Recommended Citation on productivity measures in cow-calf systems and subsequent feedlot performance and carcass characteristics of calves," Animal Industry Report: AS 664, ASL R3282. Available at: https://lib.dr.iastate.edu/ans_air/vol664/iss1/78 - AS 664 ASL R3282 Effects of extended-release eprinomectin on productivity measures in cow-calf systems and subsequent feedlot performance and carcass characteristics of calves A.S. Leaflet 3282 Claire Andresen, Graduate Student Dan Loy, Professor and Director of the Iowa Beef Center Patrick Gunn, Assistant Professor, Iowa State University Department of Animal Science Troy Brick, DVM Iowa State University Veterinary Diagnostic and Production Animal Medicine Summary and Implications The objective of this study was to estimate the impact of a single injection of extended-release eprinomectin on economically relevant production variables in beef cows and calves as well as subsequent feedlot health, performance and carcass traits of calves compared to a traditional, short-duration anthelmintic. Animals from 13 cooperator herds across 7 states were stratified within herd and assigned to 1 of 2 treatments; injectable doramectin (DOR) or injectable extended-release eprinomectin (EPR). There were no differences in preweaning cow or calf performance including weight, ADG, reproductive success, or weaning weight. Although EPR cows did have a lower incidence of pinkeye, there were no differences in pinkeye incidence of calves. Fecal samples collected at the start and end of the grazing season indicated a greater reduction in fecal egg counts (FEC) for EPR cows, however, FEC at each timepoint were well below threshold indicative of clinical parasitism. When evaluating feedlot performance, EPR calves tended to have lower incidence of morbidity, however there were no differences in growth performance. When evaluating carcass traits, calves treated with EPR during the pre-weaning phase had a greater marbling score and a greater average quality grade. While there were noted improvements for EPR calves during the feedlot phase including improved morbidity and quality grade, we believe that a lack of parasitic infection during the grazing season may have resulted in a lack of performance differences in this study. Introduction It has been well documented that gastrointestinal parasites can be detrimental to cattle health and performance. Anthelmintic treatment has long been used in all sectors of the beef industry to mitigate the negative effects of parasitic infection. In cow-calf production, anthelmintic treatment has been shown to improve cow BW and BCS, reproductive success, and calf performance. The effects of anthelmintic treatment during the feeding phase have been shown to improve live performance as well as carcass characteristics. Studies have also linked calfhood deworming treatment to improved lifetime performance including growth and health. In 2012, Merial, Inc. released the extended release version of their injectable anthelmintic drug, eprinomectin. This product label claims 100-150 days of parasite protection with one injection. To date, little research has been published regarding the effects of extended-release eprinomectin on cow-calf performance. Therefore, the objective of this study was to assess economically relevant performance parameters in cow herds following administration of extended-release eprinomectin at the start of the grazing season and to assess subsequent feedlot performance of progeny. Materials and Methods To study the effects of extended-release eprinomectin on cow-calf systems, twelve cooperator herds located in seven states (Iowa, Missouri, Indiana, Kentucky, Tennessee, Ohio, and Georgia) participated in the study. The total number of animals enrolled in the trial was 1,768 cow-calf pairs and included both spring- and fallcalving herds. Animals were stratified within herd by cow age, calf birth date, calf birth BW, and calf sex and assigned to 1 of 2 treatments; injectable doramectin (DOR; Dectomax™, Zoetis, Animal Health, Parsippany, NJ; n=879) or injectable eprinomectin (EPR; LongRa (...truncated)