Evaluation of Egyptian sheep production systems: I. Breed crosses and management systems

Our objective was to evaluate life-cycle performance of flocks of two Egypt ian breeds, Rahmani (R) and Ossimi (O), and their crosses with Finnish Land race (F) in two management systems. Management systems were one mating seas on per year (1M) and three mating seasons per 2 yr (3M). Breeds and crosses studied included purebred R and O, F-1 crosses 1/2F-1/2R (FR) and 1/2F-1/2 O (FO), and inter se matings of 1/4 F-3/4 R (RFR) and 1/4 F-3/4 O (OFO). A dynamic computer model was used to simulate animal performance and enterpri se efficiency and profit. Two measures of lifecycle feed conversion (biolog ical efficiency) were computed: kilograms of TDN input per kilograms of emp ty body weight output (TDN/EBW) and kilograms of TDN input per kilogram of carcass lean output (TDN/CLN). Profit was measured as gross margin (income minus variable costs per ewe per year, GN/EWE). Input parameters for the mo del were obtained from published results and analyses of data collected fro m experimental flocks of the same genetic stocks in Egypt. Profit for FR an d RFR was 42 and 6% higher in 1M than in 3M. However, profit for all other genetic types was 4 to 8% greater in 3M than in 1M. Breed rankings changed depending on the measure of evaluation (i.e., biological efficiency or prof it). Maximization of system output did not necessarily improve efficiency. Under accelerated lambing systems, greater overhead costs associated with l abor and feed offset gains in ewe productivity. Genetic stocks should be ma tched to resources and management systems.