Whole wheat grain feeding of lambs. V.* Effects of roughage and wheat grain mixtures

Abstract

Two slaughter trials were conducted with lambs to evaluate the effects on production and some rumen characteristics of the addition of low quality roughage (wheaten straw) and a high quality roughage (pelletized ground lucerne) to wheat grain diets. In the first trial one group of lambs was given a 1/1 mixture of whole wheat grain and chaffed wheaten straw and another chaffed lucerne hay ad libitum. Lucerne-fed lambs had significantly (P < 0.001) higher dry and organic matter intakes, grew faster and had higher levels of volatile fatty acids in their rumens than lambs offered the mixed ration, although there were no differences between rations in dry and organic matter digestibilities. The apparent nitrogen digestibility of the mixed ration was significantly (P < 0.001) lower than that of the lucerne ration. Of lambs offered the mixed ration, 46% had extensive lesions on the ventral wall of the rumen at slaughter, and these were associated with marked inappetence and loss in liveweight. In the second trial comparisons were made of diets consisting of lucerne (either alone or mixed with cracked wheat) and whole wheat grain + limestone. The effect of treating the lucerne with formaldehyde was also studied. There were no significant differences in carcass gain with the lucerne diets; parakeratosis developed in some animals on lucerne-wheat diets but did not affect productive performance. The animals offered whole wheat lost weight, two died of wheat poisoning, and several animals developed lesions on the rumen wall. _________________ *Part IV, Aust. J. Agric. Res., 26: 729 (1975).