The Change Of The Ruminal Digestive Function And The Diet Digestibility In 15～150 Day's Lamb

Two experiments were conducted to investigate the intake, digestion and rumen metabolism of the 15-150 day's lamb fed with different diets in order to understand the development of lamb's digestion functive and to provide further data for lamb fattening, especially for the production of the lamb feed. In experiment 1, 36 Romney×Chinese Merino newborn male lambs, with body weight about 4.4 kg, were divided into 3 groups (n=12 in each group) and were fed with milk replacer (Diet A), or high digestive energy/high crude protein ((H-DE/H-CP(MJ·Kg^-1/%),11.91/20) diet (Diet B), or ordinary digestive energy/ordinary crude protein (O-DE/O-CP, 8.15/14) diet (Diet C), respectively between 15-60 day's old. In experiment 2, 16 of 30-day's lambs were fitted with the rumen fistulae at 25-day's old and divided into four groups (n=4 in each group). After weaning at 30-day's old, lambs were fed with four diets: high digestive energy/high crude protein (H-DE/H-CP, 11.91 /20) (Diet 1,equals to Diet B in Exp.1), high digestive energy/ordinary crude protein (H-DE/O-CP, 11.91/14) (Diet2), ordinary digestive energy/high crude protein (O-DE/H-CP, 8.15/20) (Diet3), and ordinary digestive energy/ordinary crude protein (O-DE/O-CP, 8.15/14) (Diet 4, equals to Diet C in Exp.1). The results showed that (1) The feed intake by lamb was increased by 8-11g/d, which was linearly correlated with the age until 100-day's old. The feed intake in the H-DE groups was 15 —27% higher than that in O-DE groups. However, the feed intake was tended to stable when it arrived to 1000 g/day after 100 day's old. (2) The apparent digestibilities (AD) of OM, CP and cellulose by lambs were increased with age, AD of OM was increased by 0.19%-0.36%/d before 60-day's old, reaching to the maximum (68.4%-71.7%) at 45—60 day's old, and decreasing gradually after 75 day's old. The AD of OM was associated with feed components of diet, the the maximal AD to OM (70.5%-73.8%) was appeared at 45 days old when lambs were fed with H-DE diets, while it was appeared at 60 day's old in the lambs fed with O-DE diet. The AD of CP was increased by...