Lamb Production as Affected by Level of Protein in the Ration of the Mature Ewe1

Abstract

Three groups of 27 mature ewes were fed individually for a period of one year, rations containing 7, 10, and 13 percent total protein (3.3, 6.3, and 8.1 percent digestible crude protein), to study the influence of protein intake on body weight of the ewes and birth weight and growth of the lambs. Body weight increases of the ewes receiving the three levels of protein in their rations were approximately the same until the latter part of the gestation period when the ewes receiving the low-protein ration did not gain as rapidly as the two groups receiving higher levels. There was no difference between the group receiving 10 percent total protein in the ration and the group receiving 13 percent total protein. Birth weights of the lambs from ewes receiving the low-protein ration were significantly less than from the ewes receiving the higher protein rations. Birth weights were not influenced by increasing the total protein content of the ration from 10 to 13 percent. Lambs from ewes receiving 10 and 13 percent protein gained more during the first six weeks after birth than lambs from ewes receiving the low-protein ration. Some of the ewes on the low-protein ration had insufficient milk to nurse single lambs and none had sufficient milk for twin lambs with the exception of one. All ewes receiving the two higher levels of protein had sufficient milk for one lamb and many had sufficient for twins. On the basis of the results of this one experiment the recommended allowances of the National Research Council for digestible crude protein during early pregnancy and lactation appear to be somewhat higher than is required.