131 Five-year analysis of Kiko buck growth rate, carcass muscling and parasite resistance in a feedlot environment

From 2018 to 2023, spring-born Kiko bucks were performance tested at West Virginia University to evaluate growth rate, ultrasound carcass characteristics and parasite resistance under an artificial infection. Kiko bucks were submitted by producers from 17 different states and over 5 performance tests, 830 Kiko bucks were evaluated. Bucks were group housed and fed 16% CP pellet containing soyhulls, serving as dietary fiber component. Upon arrival, bucks were weighed, vaccinated, fecal sampled and dewormed using three different classes of anthelmintic. After a 2-wk transition period, a 63-d test period began. On-test weights were taken 12 hours apart and averaged. Then weights were taken weekly until the off-test weight, where final weights were taken 12 hours apart and averaged. Fecal sampling occurred at on-test, 21d, 42d and off-test. Ultrasonic measurement of REA at the 12th and 13th rib interface was conducted 1 wk prior to test completion. Arrival weight, on-test weight and final weight did not vary by year (P > 0.05). 5-year average delivery weight was 24.29kg (±0.85kg), average on-test weight was 27.11kg (±0.98kg), average off-test weight was 39.01kg (±1.15kg) and ADG was 0.19 kg/d (±0.02kg/d). Analysis of REA revealed a 5-year average of 9.2cm2 (±0.55cm2). For producer reporting, REA was to adjusted to 100 lbs of body weight, to remove individual weight bias. Adjusted REA (cm2/cwt) 5-year average was 10.86 cm2/cwt (±0.74 cm2/cwt). To evaluate parasite resistance all bucks were orally administered 5,000 H. contortus larvae during on-test day. Average 5-year test fecal egg count (FEC) was 195.89 eggs/g (± 85.60 eggs/g). Across these 5 years, most bucks did not develop a large FEC making evaluation of parasite resistance difficult in this setting. Nonetheless these data provide a robust evaluation of expected Kiko buck performance in a feedlot setting, particularly in reference growth and carcass metrics and should be a useful comparison for producers to make improvement in their herds and for other performance test stations across the US.