Experimental Results to Take to the Bank

Broad diversity among breeds of sheep is a precious industry resource. This breed diversity can be managed to increase performance and profit through use of crossbred ewes mated to rams of a terminal sire breed. Differences among breeds in performance for survival, growth, carcass, wool, and reproductive traits are due to the unique genetic history associated with each breed. Beneficial genetic effects of each breed can best be realized in terminal crossbreeding systems that use sire breeds to complement characteristics of maternal line crossbred ewes, thus greatly improving efficiency of commercial lamb production. Evaluation of breeds for important traits is necessary to determine their appropriate use in terminal crossbreeding systems designed for specific production and marketing situations. The relative performance of breeds can best be determined from large-scale experiments that are designed to give unbiased results. The above fundamental genetic concepts provided justification for an experiment to comprehensively evaluate several breeds of sheep. Comparative information on Romanov and Texel was limited in North America, whereas the relative performance of Montadale was unknown. The Romanov breed originated in Russia and was one of two prolific breeds (Finnsheep being the other) that was widely evaluated in numerous European, Middle Eastern, and North African countries beginning in the 1960’s. Romanov sheep were imported into Canada from France in 1981 and a flock was established at the U.S. Meat Animal Research Center (MARC) in 1986. The Texel breed has been widely used as a terminal sire breed in Europe and, more recently, in many other countries. A Texel flock was established at MARC in 1985 based on importations from Denmark and Finland. A terminal sire evaluation of Texel was done at MARC, but comparative information on reproductive traits was missing. The Montadale breed was developed in the United States from crosses of Cheviot rams and Columbia ewes, but it had not been experimentally evaluated. Experiments to gauge the merit of insufficiently characterized breeds should include one or more standard breeds to serve as a control. Dorset sheep are widely used in the U.S. sheep industry and have been included in many breed evaluations. Finnsheep contribute significantly to commercial sheep production due to high reproductive performance and have also been well characterized in genetic experiments. Therefore, Dorset and Finnsheep breeds were used as standards of comparison for general purpose and prolific breeds, respectively. The experimental objective was to determine differences among Romanov, Finnsheep, Dorset, Texel, and Montadale for survival, growth, and carcass traits of crossbred lambs and for reproductive traits of crossbred ewes in both fall and spring breeding seasons. The practical goal was to provide unbiased information so that producers can select and use breeds that maximize profits in terminal crossbreeding systems.