Study On Meat Production And Quality Of Poll Dorset×Small Tail Han Sheep Crossbred Lambs In Intensive Production System

Based on the increasing intensive production system of meat-produced sheep in farms in Xinjiang, the effects of lamb age, sex, and diet type (concentrate to forage ratio) were studied on slaughter performance, meat characteristics, and muscle chemical components of crossbreed offsprings of Poll Dorset×Small Tail Han Sheep (DHF1). The aim was to get more knowledge on slaughter performance, meat characteristics of meat-produced sheep in intensive production system, and to supply basis for development of intensive production system in Xinjiang.The experiment animals were chosen from the flocks fed in intensive production system. The treatments were slaughter age (7- and 13-month-old), sex, and two diet types (concentrate to forage ratio 68 to32 and 35 to 65). Small Tail Han Sheep (HS) with 7- and 13-month-old age were used as the control group to being compared. The animals were slaughtered for measurement of carcass characteristics and sampling for subsequent meat quality and analysis of muscle chemical components.The results showed that live body weight, meat weight, lean meat weight, and eye muscle area of 13-month-old DHF1 were higher 30% than that of 7-month-old DHF1. Live body weight, carcass weight, meat weight, and lean meat weight of 7-month-old DHF1 were higher 30% than that of 7-month-old HS. The meat production of 13-month-old DHF1 was the highest. Live body weight, carcass weight, and meat weight of 7-month-old DHF1 rams were higher 12% than that of ewes. The meat to bone ratio of rams was significantly higher than that of ewes. The slaughter performance of rams was better than that of ewes. The 7-month-old DHF1 rams fed diet with concentrate to forage ratio of 68 to32 showed higher 25% than that of ratio 36 to 65 in carcass weight, meat weight, and lean meat weight. The collagen content and shear force value in Longissimus dorsi (LD) of 7- and 13-month-old DHF1 were significantly lower than those in LD of HS with the same ages. There was no significant difference in meat characteristics between rams and ewes. The meat characteristics were not affected by diet type. The contents of dry matter, crude protein, crude fat, ash, calcium, and phosphorus in LD were not influenced by age, sex and diet type. The contents of amino acids in LD of 7- and 13-month-old DHF1 were higher to some degree than that of 7- and 13-month-old HS, but corporation of amino acids was similar. The content of linoleic acid in LD of 7-month-old DHF1 lamb was higher about 45% than that of 13-month-old lamb. The content of linlenic acid was increased by 76.8%, but cholesterol higher about 46% in 13-month-old HS lamb than that in 7-month-old HS lamb. Arachiolonic was higher in LD of 7- and 13-month-old DHF1 than that in LD of HS with the same ages. Iron in LD of 13-month-old lambs was higher than that of 13-month-old lambs. There was no significant difference in the contents of various amino acids,total essential amino acids, total non-essential amino acids, and total amino acids in LD between rams and ewes. The content of linoleic acid in LD of DHF1 rams is increased by 20.3%, but cholesterol decreased by 32% compared with DHF1 ewes. Iron in LD of 7-month-old DHF1 ewes was higher about 26% than that of rams. The diet type used in this study did not markedly affect the contents of amino acids, cholesterol, and trace minerals measured. The contents of linoleic acid and linlenic acid in LD of rams fed diet with concentrate to forage ratio of 68 to32 showed the trend of increase.This present study shows that the intensive production system, in which DHF1 rams is finished feeding diet with 68% of concentrate and slaughtered at 7-month-old, is the first selective pattern in Xinjiang lamb production. Both DHF1 rams and HS rams slaughtered at 13-month-old can produce more meat than that slaughtered at 7-month-old but meat quality does not significantly decrease.