Study Of Digestion And Metabolism And Some Blood Indexes Of Non-pregnant Small Fat Tail Ewes Fed 3 Diets With Different Ratio Of Concentrate To Roughage

18 non-pregnant Small Fat Tail ewes, with body weight of 42 Kg, were divided into 3 groups (n=6), and were fed with 3 diets which ratios of concentrate to maize straw were 20:80, 30: 70 and 40:60 respectively, to study the effect of diet ratio of Concentrate to Roughage on the digestion and metabolism of non-pregnant Small Fat Tail ewes,as well as to study some blood indices of the ewes fed with 3 diets. This paper was divided into two parts:Ⅰ.The digestion and metabolism of non-pregnant Small Fat Tail ewes which were fed with 3 diets;Ⅱ. Effects of 3 diets with different ratios of concentrate to roughage on the concentration of hormone and biochemical index in plasma of Small Fat Tail ewes.ExperimentⅠ: The results showed that the OM intake in 3 groups were 970.1±95.1,1137.3±144.8 and 1279.2±138.7g/sheep/d respectively; the intake of maize straw were 834.3±75.6,856.1±110.2 and 822.0±121.7 g/sheep/d respectively; the OM digestibility were 52.5±5.2,55.7±2.6 and 59.7±2.0 % respectively; the apparent CP digestibility were 58.7±7.6,61.1±2.6 and 62.8±2.3 % respectively;the digestibility of cellulose were 57.4±6.0, 56.1±1.1, and 53.4±3.8 % respectively;the nitrogen retention (NR) were 0.6±1.2, 3.2±2.2 and 5.9±1.6 g/sheep/d respectively, the Ca retention were 0.39±0.05, 0.59±0.10, and 0.79±0.06 g/sheep/d respectively; the P retention were 0.40±0.04,0.59±0.06 and 0.82±0.05 g/sheep/d respectively; the digestible energy obtained were 9.4±1.4, 12.3±2.1 and 15.1±1.8 MJ/sheep/d respectively, and the body weight gain were -12.4±46.1, 101.2±60.0, and 157.1±96.5 g/sheep/d respectively。It is concluded that when the diet containing 20% concentrate is fed, Small Fat Tail ewes can not maintain their body weight and the NR is only 3%; when the content of concentrate is 30 or 40%, the daily body weight gain of ewes is 100 or 150g/head, and NR is increased to 14 or 22%. Increasing the ratio of concentrate to roughage would enhance the digestibility of OM,GE,CP,Ca and P , with a tendency of decreasing the digestibility of fiber. The increasing of DE increases the retentions of N greatly, as well as Ca and P. The ratios of concentrate to roughage do not affect the intake of maize straw by Small Fat Tail.ExperimentⅡ: The results showed that the concentration of plasma sugar in 3 groups were 0.29±0.01,0.32±0.05,0.36±0.04 respectively;the concentration of plasma urea nitrogen were 0.67±0.09,0.49±0.07,0.41±0.04 respectively;the concentration of plasma insulin were: 7.10±2.42,9.60±6.82,7.21±2.0μIU/100ml respectively;during estrous period the concentration of plasma FSH were: 0.55±0.12,0.65±0.15,0.94±0.15 mIU/ml respectively;the concentration of plasma FSH were:0.40±0.14,0.52±0.10,0.72±0.24 mIU/ml respectively. It is concluded that when the diet containing 40% concentrate is fed, the concentration of plasma sugar is increased to 25%; when the diet containing 30% concentrate is fed, the concentration of plasma urea nitrogen begin to reduce, and all numeric values were in the normal physiological range; the concentration of plasma insulin is related to the intake of energy and crude protein respectively.