02326naa a2200265 a 450000100080000000500110000800800410001902400330006010000220009324500640011526000090017952016110018865000090179965000160180865000140182465000250183865000170186365000100188065300290189070000170191970000200193670000170195670000200197377300670199320756052017-09-14       1953    bl uuuu     u00u1 u    #d7 a10.2527/jas1953.121188x2DOI1 aKLOSTERMAN, E. W.  aProtein requirements of ewes during breeding and pregnancy.  c1953  aTwo experiments designed to study the protein requirements of pregnant ewes are reported. Six lots of twenty ewes each were included in each experiment. In the first experiment rations which contained approximately 7, 10, and 13 percent total crude protein were compared and in the second rations containing 5, 8, and 11 percent protein. No statistically significant differences were found between the various rations in fleece weight, birth weight of lambs, or weight of lambs at thirty days of age. Some trends were noted, however, in that the ewes fed the lowest levels of nitrogen tended to shear lighter fleeces and their twin lambs weighed slightly less at thirty days. The death loss of ewes was somewhat higher on the low-protein rations. The low nitrogen intake may have been a predisposing factor in a number of these deaths. Nitrogen balance experiments showed no significant differences in nitrogen retention between the three levels of nitrogen intake during early and mid gestation. In late pregnancy the ewes fed the higher levels of nitrogen retained significantly larger amounts. A highly significant correlation (r=0.69) was found to exist between nitrogen retention and digestible dry matter intake. Covariance analysis showed that, at the levels fed in these investigations, the amount of nitrogen stored was influenced more by the amount of dry matter digested than by the amount of nitrogen fed. The results obtained indicate that present recommendations with respect to amounts of crude protein for pregnant ewes may be decreased when the rations fed are adequate in other nutrients.  aEwes  aFeed intake  aPregnancy  aProtein concentrates  aReproduction  aSheep  aNutritional requirements1 aBOLIN, D. W.1 aBUCHANAN, M. L.1 aBOLIN, F. M.1 aDINUSSON, W. E.  tJournal of Animal Sciencegv. 12, n. 1, p. 188-200, Feb. 1953.