Effects Of Feeding Patterns On Growth,Carcass And Meat Quality Performances In New American Duroc

Since the importation of American Duroc in 1970's, the following imported American Duroc of improved genetic background and feeding management have changed a lot , it's very essential to measure its growth,carcass and meat quality performances for offering a technical reference for Duroc's production. From the point of view of Animal nutrition, this experiment was focused on the three performance aspects: The effects of different live weights(1),seasons(2),and feeding patterns(3) on growth,carcass and meat quality performances of the New American Duroc on the feeding condition of Anhui. Experiment 1:A Report on Growth,Carcass and Meat Quality Performances of the New American Duroc in Ahhui Province. From U.S. Anhui Animal Improvement Station imported 100 American Duroc (15 male, 85 female) and reproduced them for 2 generations. The imported Duroc and the 659 offspring of first generation were tested. The performances of the imported were 145±13cm, 153±14cm, 170±13cm for the male body length at 6, 10, 18 month of age separately. The litter size was 11.5±2.0(the second embryo). The growing performances for the offspring were 8.3±2.1kg and 33.0±4.5kg of body weight at 28 days and 70 days of age separately. The growing days for 100kg body weight was 148.0±13.2 days. The average daily gain was 859g and the feed conversion rate was 2.46:1. As regard to meat quality they had 51.70±2.44 for L* and 42.19±4.84N for shearing force. The results imply that the new imported Duroc have very good capacity of growth, reproduction and meat quality. The genplasma of modern American Duroc has been improved to a certain extent. Experiment 2: Effects on Carcass and Meat Quality Performances of American Duroc at Different Live Weights. 48 Durocs were randomly selected at 28 days of age from the second generation of American Duroc Breeding herd which was imported in 2001 from U.S. The 48 gilts were fed in nursery house till they were 70 days of age at about 33 kg body weight. For the growing-finishing phases the pigs were fed with diets at DE l3.3~13.1MJ/Kg and CP 18.01％~16.03％. Randomly 12 (4×3,4 individuals for each body weight phase) individuals from the 48 Durocs were selected and slaughtered at about 100 kg,120 kg and 150 kg live weight at different growing phases separately to examine the influence of body weight or age on the carcass ad meat quality. The results indicated that the lean percentage decreased significantly from 66.8% to 62.4% when live weight in creased from 100 kg to 150 kg. It means that Duroc gilts are lean enough to current market demands even they are finished as later as 180 days of age at 150 kg live weight. However the increased leaf fat and viscera fat need to be monitored. In addition, higher intramuscular fat percentages were for 120/150 kg live weight (3.32%/3.69%) than that for 100 kg (2.86%). The results imply better meat quality for higher live weight with higher intramuscular fat at the expense of a little worse tenderness. Experiment 3:The Influence of Season on the Carcass and Meat Performances in American Duroc. 36 Duroc pigs of each group were randomly selected at 28 days of age from the second generation of American Duroc Breeding herd in season 1(autumn-winter) and season 2(spring-summer). The 36 Duroc pigs of each group were fed in nursery house till they were 70 days of age at about 33 kg body weight. For the growing-finishing phases the pigs were fed with diets at DE l3.3~13.1MJ/Kg and CP 18.01％~16.03％ till they were 100 kg. Randomly 18 individuals from the each group were selected and slaughtered to examine the influence of different season on the carcass ad meat quality. The results indicated that season had no significant influence on the carcass parameters. As regard to meat parameters, lower a* value(6.47±0.73) and driploss(3.26±0.88) were for the season of autumn-winter than those(8.78±0.85, 5.63±0.64) for the season of spring-summer. Biochemistry parameters of different seasons were relative stabilization. The relative content of Fatty acid...