Effect of digestible energy and crude protein intake on the wool growth in fiber length of the Aohan fine-wool sheep

The 5×5 factorial experimental design (5 digestible energy levels by 5 crude protein levels) was used to study the effects of different digestible energy (DE) and crude protein (CP) intake on the wool growth in fiber length of the Aohan fine-wool sheep. 125 2-3 years old un-pregnant adult ewes were randomly divided into 25 treatments with 5 replicates each. They were fed with 25 different dietaries with the combinations of the DE and CP at 85%,100%,115%,130%,and 145% of the maintenance requirement. The amount of wool grown in fiber length during experimental stage was measured six months later. The results showed that,when DE intake ranged from 85% to 145% of the maintenance requirement,there was a cubic regression relationship between DE consumption and amount of the wool growth in fiber length and two inflection points are located nearby 100% and 130% of the maintenance requirement(R0.99),respectively. Wool growth in fiber length was significantly improved by 10.70% on average,when DE consumption increased from 85% to 100% of the maintenance requirement. However,the wool growth in fiber length had no significant improvement,if DE consumption increased from 100% to 130% of the maintenance requirement. Growth of the wool only raised 4.58% on average when DE consumption increased from 130% to 145% of the maintenance requirement. The regression relationship between CP consumption and wool growth in fiber length looks like a quadratic trend (R0.86). Wool growth in fiber length significantly increased by 7.71% on average if the CP consumption increased from 85% to 115% of the maintenance requirement. However,there was no increment in wool growth if CP consumption increased from 115% to 145% of the maintenance requirement. DE requirement of wool growth couldn't less than maintenance requirement,and CP requirement of wool growth should be increased by 15% at the basis of the maintenance requirement. The result of this study shows no interaction effects on wool growth in fiber length between DE and CP consumption.