161 Evaluation of Feeding Behavior of Katahdin Lambs DuringHaemonchus Contortous Infection

Abstract

Abstract Internal parasites, specifically Haemonchus contortus (Hc), are detrimental to flock profitability. Loss of production efficiency and death in severe cases, contribute to the economic burden documented worldwide. Understanding the extensive impact gastrointestinal nematodes (GIN) have on nutritional loss and feeding behavior may prove valuable. The aim of this study was to evaluate infected Katahdin lambs for feeding behavior in a Growsafe system. Katahdin ewes from the Virginia Tech Southwest Agriculture Research and Extension Center in Glade Spring, Virginia were mated to rams (n = 8) of varying PWEC EBV genotype. A subset of lambs was selected for evaluation in a feedlot environment and transported to West Virginia University’s Animal Science Farm. Lambs were fed a complete pellet (16% CP) ad libitum while individual intake was measured with a GrowSafe system. One half of the lambs from each sire PWEC EBV group were infected with 5,000 Hc L3 larvae and observed for 5 weeks in year (Y1) and 6 weeks in year 2 (Y2) alongside uninfected contemporaries. Artificial Hc infection resulted in lambs becoming moderately infected with FEC ranging from (0 –208 eggs/g). Daily feeding behavior was collected on all lambs, directly related to feed consumption/removal. Number of visits, duration of visits and duration spent feeding/day were analyzed to evaluate feeding behavior. Visit duration, daily duration, and visit intake was not statistically different for infected vs uninfected lambs. However, significance was detected in both years for feeding behavior between sex. Ram lambs exhibited greater duration per visit than ewe lambs in Y1 and Y2 (89.7 vs. 78.6 seconds/visit, 122.8 vs. 82.4 seconds/visit respectively; P < 0.05). Increased feeding durations for ram lambs resulted in rams exhibiting reduced frequency of feeding events compared with ewe lambs in Y1 and Y2 (36.3 vs. 43.9 visits, 25.8 vs. 40.8 visits/day respectively; P < 0.01). Increased duration of feeding/visit in ram lambs also resulted in greater feed intake/visit compared with ewe lambs in Y1 (58.7 vs. 42.7 g/visit; P < 0.0001). Feed intake and total daily feeding duration was not significantly different between sex. Further analysis is needed with greater levels of parasite infection to detect parasite interaction on feeding behavior. However, feeding behavior differences between sex of lambs is a significant factor nutritional consumption of feedlot environments.