The effect of the digestible undegradable protein concentration of concentrates and protein source offered to ewes in late pregnancy on colostrum production and lamb performance

An experiment was carried out to determine the effect of level of digestible undegradable protein (DUP) concentration and source of protein offered to ewes in late pregnancy on subsequent colostrum production and lamb performance. Ninety-one twin-bearing ewes of mixed breeds were offered grass silage and one of six concentrate treatments for a period of 6 weeks prior to lambing. The concentrates were formulated to provide increasing levels of DUP from approximately 13-65 g DUP/kg DM. The DUP was supplied in the form of xylose-treated soyabean (soypass) or fishmeal. Silage was offered at a constant rate of approximately 0.5 kg dry matter per day. Protein source and DUP concentration of the concentrate had no significant effect (P>0.05) on ewe blood composition, colostrum yield and quality, lamb birth weight and lamb live weight gain from birth to weaning. The results of this study indicate that, for ewes with a mean condition score of 2.6 at 6 weeks prior to lambing and offered well fermented silage, protein source i.e., soypass versus fishmeal or level of DUP in the concentrate have no significant effect on ewe performance, in terms of colostrum production or lamb birth weight. (C) 1999 Elsevier Science B.V. All rights reserved.