Effect of a partial replacement of ground corn grain with dried whey on the quality of the ration based on different forage species in wether sheep

Abstract

An in vivo study was conducted into the effects of partial replacement of dried ground corn grain with dried whey – as a supplement to alfalfa haylage (AH) or Italian ryegrass haylage (IRH) - on ad libitum intake, in vivo digestibility and N retention in wether sheep. The chemical composition of AH and IRH was roughly the same, except for the crude protein (CP) content which was much higher in AH compared with IRH. Sheep fed the AH-based diet had higher feed intake. Higher CP digestibility and higher N retention, as well as higher levels of excreted N, were shown compared IRH-based diet. The IRH-based diet increased the digestibility of chemical parameters studied, except CP and starch. The partial replacement of corn grain with dried whey reduced the intake of acid detergent fibre (ADF), improved the starch digestibility in AH and IRH-based diets, and increased the overall N intake in wethers fed the AH-based diet. In practical conditions, replacing 10% of corn grain with dried whey in a ration based on higher quality forage is a way to increase N intake in sheep. In conclusion, the partial replacement of corn grain with dried whey in a forage-based diet with higher CP content improves the nitrogen efficiency in the diet of wether sheep.

Keywords

• whey in the diet of sheep
• alfalfa haylage
• italian ryegrass haylage
• intake
• digestibility
• n retention