Effect of Nutrition on the Productivity of Range Sheep

Abstract

Four hundred and fifty range ewes from each of two owners consisting of six age groups were maintained on desert-type winter range during the winter of 1954–55. Ten treatments including range forage only, and supplemental feeds of energy, protein and phosphorus during three seasons, November to April, January to April, and January to March were used. Body condition changes are introduced as a measure of response. They help define body weight and they show that ewe gains in the spring are not necessarily due to increased flesh on the ewe. Comparison of treated animals to nontreated animals did indicate definite improvement in maintenance of body weight and condition during the winter, in wool production and in lamb birth weights but not weaning weights. Differential feed treatments indicated no difference in lamb production among kinds of supplement and season. The midwinter fed groups produced more wool than those fed during other seasons. Kind of supplement had no effect on wool production. Protein feed and all-winter feeding maintained body weight and condition better than other combinations of feeding. Three-year-old ewes followed by 4-year-olds produced the most pounds of lamb. Yearlings, 2-year olds and 3-year-olds had nearly the same wool production. When combining lamb and wool production the 3- and 4-year-olds were the best producers. The yearling ewes maintained weight and condition better than the other age groups. Large ownership differences were observed. Owner 1's ewes lost more body weight and condition, produced more pounds of lamb and less wool than the ewes from Owner 2. These ownership differences, apparently due to previous genetic and environmental influences, emphasize another problem in the interpretation of nutrition experiments. Copyright © . .