Abstract:

Three mixtures of neutral detergent fiber from sheep roughage(corn straw，wheat straw and silage corn stalks）with soybean meal protein according to the proportions of 1.8:1, 2.2:1, 2.6:1, 3.0:1, 3.4:1 and 3.8:1 respectively were conducted for in vitro digestive test to determine the digestibility of dry matter and organic matter，changes of pH of compositions between neutral detergent fiber from different plants and crude protein, and NH3-N concentration of fermentative substrate, so that the parameters for preparation of sheep diets could be provided. The results showed that the digestibility of dry matter and organic matter were the lowest when NDF/CP of mixtures of corn straw and soybean meal was 3.8:1 and the highest digestibility appeared when the ration was 2.2:1. The digestibility of mixtures of wheat straw and soybean meal were similar to the mixtures of corn straw and soybean meal, the minimum and the maximum appeared separately when the rations of NDF/CP was 3.8:1 and 2.6~3.0:1. The digestibility of mixtures of silage corn stalk and soybean meal increased with protein proportion, the minimum and the maximum appeared separately when the rations of NDF/CP was 3.8:1 and 1.8:1. There was no significant difference between pH of mixtures（P＞0.05）. The NH3-N concentrations increased with protein proportion, but there was no significant difference between different levels. The NH3-N concentrations were not affected by NDF from different pants after mixtures were cultured for 96 hours.