The Development of the Digestion and Metabolism of the Rumen in 30~150 Days' Lamb Fed with 4 Diets

16 of 30 days' Romney Marsh×Xinjiang Merino male lambs,at the body weight of 6~10 kg,with rumen fistula,were divided into 4 groups,and were fed 4 diets with DE/CP(MJ/%) of 11.91/20,11.91/14,8.15/20 and 8.15/14 respectively,to study the development of the digestion and metabolism in rumen.At the last 3 days of every 15 days,the rumen fluid were sampled at 0,1,3,6 and 9 hours after feeding during the age of 30~150 days for assaying.The results showed that the pH,NH_3-N,propionic acid,and acetic+propionic+butyric acids concentrations in rumen fluid were affected by dietary nutrient level,increased with the age, and were stable after 100 days' age.The effect of age and dietary nutrient level on acetic acid in rumen fluid was less.The rumen fluid volume was increased almost by 15 times in 120 days,as well was related with nutrient level of diet.This study elites that the development of the digestion and metabolism of rumen is progressive,which is mainly dependent on the increase of rumen fluid volume,and at 100 days age it presents a stable tendency.