Submitted to: The Shepherd
Publication Type: Abstract Only
Publication Acceptance Date: 6/18/2001
Publication Date: 7/3/2001
Citation: Leymaster, K.A. 2001. Evaluation of wool and hair breeds under intensive and extensive production systems. The Shepherd. 46(8):34-35. Interpretive Summary:
Technical Abstract: The experimental objective is to evaluate production efficiency under both intensive and easy-care production systems of four types of crossbred ewes. Varying levels of reproductive efficiency and easy-care attributes will be created by mating Romanov ewes to Rambouillet, Dorset, Dorper, and Katahdin rams. Purebred and crossbred Romanov ewes excel in all aspects of reproduction and therefore will make up one-half of each crossbred. Wool (Rambouillet and Dorset) and hair (Dorper and Katahdin) breeds are included for comparative purposes as the long-term value of wool is unknown. Rambouillet and Dorper provide a wool-hair comparison for breeds developed under extensive, arid conditions, while Dorset and Katahdin offer a similar contrast for breeds adapted to more favorable production conditions. About 360 Romanov ewes will be single-sire mated to Rambouillet, Dorset, Dorper, and Katahdin rams each of three years (2000, 2001, and 2002). Half of the ewes will be exposed during October and half during December. A minimum of 18 rams, all by different sires, will be sampled from each breed over three years. The goal is to produce about 150 crossbred ewes of each type for each production system, a total of roughly 1,200 ewes over the three-year period. Ewes conceived in October will go into an intensive production system, whereas ewes conceived in December will go into an easy-care (pasture) production system. Ewes of each type will be multi-sire mated to rams of a terminal-sire breed. In the intensive system, ewes will be limited to rearing two lambs with additional lambs artificially reared. Ewes in the easy-care production system will be completely responsible for rearing of all lambs. The four types of crossbred ewes will be evaluated over three parities with each ewe remaining in a single production system.