Study On Nutrition Utilization Of Lambs When Fed Milk Replacers Of Different Nutrition Levels And Early-weaned Time Of Lambs

In mis research, sucking lambs at different days fed with milk replacers of different nutrition levels were studied on growth performance, nutritional digestibility and the relationship between nutritional digestibility and lambs' age. Early-weaned lambs' blood serum index and early-weaning technique were studied by feeding test.Test 1: Twelve seven-day-old male lambs (Torset ♂ × Small tailed sheep ♀) in good condition were randomly divided into three groups. Lambs of group A were fed with milk replacers of low-nutrition level. Group B were fed with milk replacers of middle-nutrition level. Group C were fed with milk replacers of high-nutrition level. It last 57 days.Feeding trial showed as follows. There was no obvious difference among those three groups in weight gain when fed with milk replacers of different nutrition levels (P>0.05). Weight (kg) of lambs at day 10-60 increased direct linearly with days (R~2= 0.9849). Daily weight gain of all groups had the trend to increase with nutrition level (P<0.05), and average daily weight gain (g) linearly increased with days (R~2=0.9705). Feed conversion of group A, B, C were 1.48, 1.40 and 1.32, respectively. Group C, i.e. milk replacer of high-nutrition level was the best.Total collections of feces and urine were made to investigate the nutrient utilization and digestion efficiency when lambs at day 13-16, 23-26, 33-36, 43-46 and 53-56. The results were concluded as follows. At the same ages, though different nutrition contents in milk replacers made no significant influence on nutrition utilizations (P>0.05), nutrition digestibilities increased first and then decreased as nutrition level rising. There were directly linear correlation between the nutrition utilizations and days of lambs (R~2 ≥0.8453). The apparent nutrition digestibility of lambs increased with day. Lambs fed with milk replacer of mid-nutrition had the best nutrition utilizations.Considering both growth performance and nutrient utilization and digestion efficiency, milk replacer of middle-nutrition level, i.e. contenting CP 26%, EE 14%, GE 19MJ/kg, Ca 1.48% and P 0.78%, was best for lambs.Test 2: In order to confirm the best early-weaned time of lambs, the influence of early-weaned time on lambs' growth performance and blood serum index were studied. As test 1, sixteen lambs were divided into four groups randomly, group D were the control, group A weaned at day 7, group B weaned at day 17 and group C weaned at day 27.