Periparturient ewe cereal nutritional management

Abstract

The objective was to determine effects of feeding diets with high vs. low levels of ground corn grain (CN) vs. combined ground wheat and barley grains (WB) on intake, rumen fermentation, colostrum and milk properties, and blood metabolites of periparturient sheep. Twenty Afshari×Merino ewes were used in a completely randomized design study from 24d prepartum through 21d postpartum. Ewes were kept indoor in individual boxes and received once daily at 0900h total mixed rations (TMR) containing either (1) high or (2) low concentrate diets based on either (1) 100% CN or (2) 50:50 ratio of ground wheat+barley grains (WB) in a 2×2 factorial arrangement. Prepartal DMI numerically increased by feeding CN vs. WB, while high vs. low CN improved postpartum DMI. Lambing DMI tended to increase with the high vs. low WB. Feeding CN vs. WB, and feeding both CN and WB at low vs. high level increased fecal pH. Postpartal rumen pH was lower with the high vs. low WB (5.7 vs. 6.2). Rumen concentrations of propionate were lower and of acetate were higher with low vs. high grain levels. Colostrum properties, postpartal urine pH, lamb weight at birth and 21-d of age, and placental weight and expulsion time were unaffected. Milk and milk fat yields were increased by high vs. low grain diets. Plasma glucose was increased by feeding high vs. low WB, while CN vs. WB tended to reduce peripartal plasma NEFA and increased insulin to NEFA ratio. Findings establish that intake, rumen fermentation, mammary secretions, and peripheral metabolism indicators can be manipulated by periparturient management of cereal nutrition. These suggest opportunities to optimize periparturient ewe physiology and performance through manipulating cereal grains nutritional management.