EVALUATION OF LEAN MEAT SELECTION EFFICIENCY AND RESPONSE IN KATAHDIN SHEEP

This project seeks to establish a lean muscle meat sheep flock selected on the objective ultrasound measurements in live animals for predicted carcass traits and evaluate the selection efficiency, response, and genetic gain in Katahdin sheep flocks. Sheep are an ideal livestock species for operations with small acreage. In fact, most US operations raise fewer than 100 head, and 85 percent of all farms owned fewer than 100 sheep. There are more than 2,200 farms involved in raising about 185,000 sheep and goats in Missouri, with a great potential for market expansion. Sheep are seasonal (fall) breeders, with a five-month gestation period, and with lambing in the following spring and the marketing of lambs occurring from late summer to fall. Consequently, it takes about nine to 10 months to produce meat products for consumption. There is an urgent need for producers and consumers to demonstrate a highly efficient meat sheep selection and marketing system.This proposal is to investigate the efficiency of lean meat selection in Katahdin sheep, develop a lean meat breeding index, and demonstrate a sustainable lamb production system. Ultrasound scanning is becoming a preferred, noninvasive, precise, and speedy real-time test tool in meat animal selection and marketing. With this technology, sheep producers are able to select animals based on leaner muscle and lower fat content carcass predictability without any invasive assessment of animals. However, there is little experimental data and technical information available about the selection of lean muscle efficiency, response, and genetic gain when applying the ultrasound measurement technique in the US sheep industry. Currently, there is no selection or genetic evaluation of lamb carcass traits in hair sheep breeds and an urgent need for producers and consumers to demonstrate a highly efficient meat sheep selection and marketing system. Therefore, this lean muscle selection project will facilitate the selection of animals with greater muscling and the potential for higher-yielding lamb carcasses to produce progeny with a higher carcass weight and a valuable shelf product as well as increase the genetic gain in lean muscle traits. The project is to accomplish the following three objectives:(a) To establish a lean meat sheep flock selected on ultrasound-measured carcass traits from the loin eye muscle area, loin eye muscle depth, loin eye muscle width, and backfat thickness.(b) To develop a lean sheep index for breeding animal selection, postweaning growth rate, and estimated progeny performance differences in high lean muscle and low lean muscle lines.(c) To compare the weaning weight, postweaning growth, and reproduction performance of high and low lean selection flocks.