Abstract :
This study was conducted in order to evaluate the effects of substitution of a high degradable protein source, soybean meal
(SBM), with low degradable, corn gluten meal (CGM), and to determine the effects of ruminally protected lysine (lys) on the
performance of lactating ewes fed a ration calculated to be first-limiting in lys. Forty-two multiparous Chios ewes were examined
in a 8-week study that started at parturition. Animals were fed in groups (14 ewes), with three isocaloric–isonitrogenous–isofibrous
rations. Treatments were (A) SBM and wheat bran (SW), (B) CGM and corn gluten feed (GF), and (C) CGM and CGF plus
10 g/d lys (GFL). GF and GFL groups resulted in higher fat, protein and solids non-fat (SNF) content in milk, but SW group
was associated with a tendency for higher milk yield compared to GF, somewhat mitigated by lys supplementation in group
GFL. The daily production of protein was higher in SW than in GF, but this difference was eliminated by lys supplementation,
suggesting that lys was limiting in GF ration. Treatments did not differ in exportation of energy in milk, assessed by fat corrected
milk (FCM), which is consistent with similar growth rate of the lambs. The reduced blood glucose level in ewes consuming
rations containing CGM may be due to high proportion in UP of those diets.
© 2004 Elsevier B.V. All rights reserved
Keywords :
protein source , serum metabolites , lysine , Ewes milk