Effects of Wheat Grain in Pre-Partum Diets on Plasma Metabolites and Hormones in Peripartum Cows

Sixty eight Holstein cows, 38 primiparous and 30 multiparous, were employed in a randomized complete block design to evaluate the effects of 2 diets of varied rumine fermentable carbohydrate sources (Corn Grain (CG) and Wheat Grain (WG)) on blood metabolites and hormones during periparturint period. Primiparous and multiparous cows were blocked by parity. The cows were fed diets as total mixed ration with similar energy and crude protein contents including: 1) 18.6% CG, or 2) 18.6% WG from 23±9 d relative to expected calving until calving. Following calving, all the animals received the same lactation diet until 28 d. Blood sampling was carried out weekly and on days –1, 0, and +1 relative to calving. The results indicated that, there was no significant effect of the pre-partum carbohydrate source on the overall plasma concentration of glucose, non-esterified fatty acid,? -hydroxybutyrate, triglyceride, cholesterol, albumin, cratinin, plasma urea nitrogen, calcium, phosphorous, magnesium, aspartate aminotransferase, alkaline phosphatase, insulin, and cortisol in multiparous and primiparous cows. The multiparous cows fed the WG diet during the pre-partum period had greater glucose (P=0.09) at pre-partum period and greater calcium at postpartum period (P=0.09) compared with multiparous cows fed the CG diet. Primiparous cows fed the WG diet had a higher plasma calcium in the first week of lactation (P<0.5). It is finally concluded that feeding pre-partum diets containing rolled wheat grain may improve metabolism and smoothen the adaptation from gestation to lactation in peripartum Holstein cows.