Influence of nutrition in winter on growth of nomadic grazing livestock in the Gobi region

One hundred and thirty-two weaned，castrated，nomadic grazing lambs were divided into2groups(feeding and control groups，with a mean body weight of 26.34+2.07 and 26.20+2.12 Kg，respectively)and subjected to a2-year experiment。Body weight loss in winter was significantly inhibited by supplemental feeding in the feeding group(P&lt；0.005)，but weight gain during the weight gain period from April through November was greater in the control group and the body weight rapidly recovered to the mean weight of the feeding group by August，in the middle of the weight gain period.No significant difference was noted between the 2groups thereafter until November，the end of the period。No apparent influences of supplemental feeding were noted in the carcass，bone，muscle，or fat weight in any period.It was suggested that the inhibition of weight loss in winter does not necessarily improve later growth.Several influences on the carcass composition were noted：the muscle and fat rates were significantly different between the groups at initiation and in April in the final year，suggesting that the muscle rate was elevated by supplemental feeding in winter。The herbage intake measured employing the n-alkane marker method in June and August 2000 and June，August，and September 2001 and the mean number of ingested plant species by season were 2018±473.460±320 gDM/day and 12-4，respectively，showing wide ranges and marked influences of the growth condition of grassland plants in the measured years or seasons.The herbage intake tended to be higher in the control than in the feeding group，and the difference was significant in September2001(P&lt；0.005)。Using lumen-fistulated sheep in the feeding and control groups，grass digestibility was measured under the grazing condition employing the simple Dacron bag method。The digestibility was influenced by years and seasons and widely ranged from 63.8±12.81to80.3±8.99%DM，but the value of ingested grass was relatively high.

One hundred and thirty-two weaned, castrated, nomadic grazing lambs were divided into 2 groups (feeding and control groups, with a mean body weight of 26.34+2.07 and 26.20+2.12 Kg, respectively) and subjected to a 2-year experiment. Body weight loss in winter was significantly inhibited by supplemental feeding in the feeding group (P<0.005), but weight gain during the weight gain period from April through November was greater in the control group and the body weight rapidly recovered to the mean weight of the feeding group by August, in the middle of the weight gain period. No significant difference was noted between the 2 groups thereafter until November, the end of the period. No apparent influences of supplemental feeding were noted in the carcass, bone, muscle, or fat weight in any period. It was suggested that the inhibition of weight loss in winter does not necessarily improve later growth. Several influences on the carcass composition were noted : the muscle and fat rates were significantly different between the groups at initiation and in April in the final year, suggesting that the muscle rate was elevated by supplemental feeding in winter. The herbage intake measured employing the n-alkane marker method in June and August 2000 and June, August, and September 2001 and the mean number of ingested plant species by season were 2018±473・460±320gDM/day and 12-4, respectively, showing wide ranges and marked influences of the growth condition of grassland plants in the measured years or seasons. The herbage intake tended to be higher in the control than in the feeding group, and the difference was significant in September 2001 (P<0.005). Using lumen-fistulated sheep in the feeding and control groups, grass digestibility was measured under the grazing condition employing the simple Dacron bag method. The digestibility was influenced by years and seasons and widely ranged from 63.8±12.81 to 80.3±8.99 %DM, but the value of ingested grass was relatively high.