Research On Fattening Performance Of Alpine Merino Lamb Stall-fed In The Minqin Oasis

The raising mode is of great significance to the development of animal husbandry,and is closely related to the economic benefits of livestock breeding and farms.Properly changing the traditional raising mode"high forage+low concentrate"to a"low forage+high concentrate"raising mode has a positive impact on sheep fattening.The proper ratio can maximize the role of the diet,and then affect the growth performance and meat quality of sheep.Alpine Merino sheep,as a newly cultivated wool and meat dual-purpose sheep breed,has the characteristics of moderate adaptability and high breeding efficiency.In previous research lacked systematism on the fattening performance of Alpine Merino sheep.And then,the present studies selected about 3-month old Alpine Merino lambs from pastoral areas（Sunan grassland）for exploring the fattening performance in the agricultural area（Minqin house feeding）.According to the gender of the lamb and the ratio of forage in the total mixed pellet ration,the lambs was divided into 4 group,i.e.,the higher forage ratio male group（MHF）,the lower forage ratio male group（MLF）,the higher forage ratio female group（FHF）and the lower forage ratio female group（FLF）.After3-month fattening,it was determined its production performance,rumen fermentation parameters,apparent digestibility of nutrients,slaughter indicators,gastrointestinal tissue morphology and meat quality performance through the feeding trial,digestion and metabolism trial and slaughter experiment.The main findings were as follows:（1）There were significant gender effects（P<0.01）on the average daily feed intake,average daily weight gain,initial weight,final weight,ratio of feed to gain of stall-fed Alpine Merino lambs,and the male lamb was significantly higher than the female lamb（P<0.01）.The average daily feed intake,final weight,average daily weight gain and feed conversion rate were significantly affected by the dietary forage ratio（P<0.05）,and Alpine Merino lambs fed LF were significantly higher than HF group（P<0.05）.During the whole experimental period,the pH between the four groups was not significantly affected by the diet（P>0.05）,while the total volatile fatty acids was significantly affected（P<0.01）.（2）During the entire experimental period,the intake and discharge of DM,OM,NDF,ADF among lambs in the different diets were significantly higher in LF than in HF group（P<0.05）,but the digestibility of DM,OM,NDF,ADF was not significantly different（P>0.05）.The nitrogen intake,fecal nitrogen,nitrogen digestibility,nitrogen retention,nitrogen retention rate were significantly affected by the forage ratio（P<0.05）.In addition,there were significant differences of nitrogen intake,fecal nitrogen and nitrogen digestibility between genders（P<0.05）,and the urine nitrogen was significantly affected by the interaction of lamb gender and diet（P<0.05）.（3）Except for backfat thickness,there were differences in slaughter weight,slaughter rate,GR value,and eye muscle area among groups（P<0.05）,and the LF group was significantly higher than the HF group（P<0.05）,and the slaughter of live weight,carcass weight and eye muscle area of the lambs were extremely significant higher for male lamb than female lamb groups（P<0.01）.The width of ruminal nipple in LF group was significantly higher than that of HF group（P<0.01）,the villi length and crypt depth ratio（V/C）was very significantly different between different diets（P<0.01）.（4）There were extremely significant differences in the redness and yellowness of muscles with different ratios of forage diets（P<0.01）,and a significant difference in the pH_45min of mutton（P<0.05）.The conventional chemical composition of Alpine Merino lamb muscle was not significantly different among different diets（P>0.05）.The content of C16:0 and C16:1 between groups were significantly affected by the ratio of forage（P<0.05）,and the interaction between gender and diet had no significant effect on muscle fatty acid content（P>0.05）.In summary,when Alpine Merino lambs fattened off-site were fed with a total mixed pellet ration with different ratio of forage,the total mixed pellet ration with a lower ratio of forage was greater the average daily feed intake（1.55 kg/d）,average daily gain（203.14 g/d）,carcass weight（21.97 kg）and slaughter rate（47.86%）than in the higher forage ratio treatment.