Effect Of Two Methods And Levels Of Supplementation Of Urea In Corn Stover-based Diet On Digestion And Metabolism In Sheep

Experiment 1:30male Xinjiang Merino sheep of 17kg body weight, 5 month-old, were divided into 5groups (n=6 each group) , supplied with corn stover-based diet (no urea , group 1 ) , 7g urea /sheep/day(urea mixed with the concentration and fed twice per day, group 2) , 15g urea /sheep/day (urea mixed withthe concentration and fed twice per day , group 3), 7g urea /sheep/day (urea soluted and spouted on stover,group 4) , 15g urea /sheep/day (urea soluted and spouted on stover, group 5) , to study the effect of twomethods and two levers of supplementation of urea on digestion and metabolism in sheep. The resultsshowed that the intake of corn-stover in each group were 484.1±59.9,474.8±55.5,464.8±56.1,494.9±44.4and 431.9±40.5 g/sheep/day respectively ; the OM digestibility were 58.72±2.67a, 60.74±3.30a,59.43±1.84a , 58.84±3.59a and 55.13±3.51b% respectively;the digestibility of cellulose were 37.87±3.92ab,41.39±4.96a, 39.70±4.78a ,39.53±6.62a and 32.75±4.15b% respectively;the digestibility of hemi-cellulosewere 54.14±4.82 ab, 54.14±3.50 ab, 55.25±2.60a ,52.96±7.51 ab and 48.08±7.24b% respectively;thedigestibility of CP were 59.58±5.43 , 71.54±5.14ab, 76.92±4.64a ,67.47±3.23band 72.68±2.70ab%respectively;the nitrogen retention rate were 13.8±4.2 , 18.5±5.0, 17.4±6.9,18.6±2.1 and 12.0±6.1%respectively. The efficiency of N utilization of urea in group 2, 3, 4 and 5 were 34%, 22% , 37% and 9%respectively. It is concluded that comparing with feeding twice of urea per day, spraying urea into cornstover has little effect on the intake, digestion and nitrogen retention of sheep, or even worse when higherdose of urea is fed.Experiment 2:Five ruminally and duodenaly cannulated Xinjiang Merino sheep of 24kg body weight ,assigned in a 5×5 Latin square experiment , were supplied with corn stover-based diet (no urea , group 1 ) ,7g urea /sheep/day (urea mixed with the concentration and fed twice per day, group 2) , 10.5g urea/sheep/day (urea mixed with the concentration and fed twice per day , group 3), 7g urea /sheep/day (ureasoluted and spouted on stover, group 4) , 10.5g urea /sheep/day (urea soluted and spouted on stover, group5) , to study the effect of two methods and two levers of supplementation of urea on digestion andmetabolism in rumen . The results showed that the intake of corn-stover in each group were 675.77±77.73 ,624.91±127.49 , 656.58±80.56 , 652.50±95.73 and 620.91±95.51g;the OM digestibility in rumen were53.61±4.28,50.23±7.31,55.26±5.10,57.13±5.74 and 54.08±3.26% respectively;the digestibility ofcellulose in rumen were 62.62±2.88,60.86±3.61,65.41±3.57,65.82±5.07 and 67.21±4.67% respectively;the digestibility of hemi-cellulose in rumen were 75.20±6.15,73.43±3.54,74.81±4.37,75.86±7.99 and75.45±1.81% respectively ;the number of CP flowed to the small intestine were 74.08±13.31,77.51±22.47, 69.41±12.88, 67.09±14.27 和71.19±13.82g/sheep/day respectively . It is concluded that whensupplied 7g or 10.5g urea for sheep , feeding twice of urea per day or spraying urea into corn stover haslittle effect on digestion of sheep in rumen and on N flowing to the cannulate .