Abstract:
Proc. Aust. Soc. Anim. Prod. Vol. 17 403 GROWTH PERFORMANCE AND CARCASS COMPOSITION OF GROWING PIGS DERIVED FROM TWO HERDS L.R. GILES There is a lack of information on the growth performance and carcass composition of 'purebred' strains of growing pigs when compared to 'hybrid' pigs derived from large breeding companies within NSW. The aim of this study was to compare the growth performance and carcass composition of growing pigs derived from the Pig Research Unit at Wollongbar and a pig breeding company, Parkville Piggeries, Scone, NSW when housed under controlled experimental conditions. Ten piglets (six males and four females) were introduced from Parkville Piggeries to the Pig Research Unit at Wollongbar after hysterectomy of three sows and fostered onto a recently farrowed sow as a litter group. At seven weeks of age the Parkville pigs were matched with ten Wollongbar pigs, randomly selected from 25 litters, on the basis of sex and seven week weight, and housed in individual pens with free access to nipple drinkers and a minimum temperature of 22oc. A wheat and soya--bean meal diet, estimated to contain 14.5 MJ/kg digestible energy (DE), air-dry basis, was supplemented with free lysine to contain 0.84 and 0.60 g total lysine/MJ DE and fed during the 20-50 and 50-80 kg liveweight phases respectively. All pigs,were fed ad libitum and slaughtered after reaching 85 kg live weight. The left side of each carcass was divided into ham, middle and shoulder and physically dissected into muscle, bone and fat. The main findings from this study were (a) the similarity in food intake and PZ backfat of both herds; and (b) pigs derived from Parkville sows had more carcass muscle and less bone content than the Wollongbar pigs at the same carcass weight and PZ backfat. These findings confirm other Australian studies (McPhee 1985) and indicate considerable variation in tissue composition within the Australian herd. The study indicates that a prediction equation of lean content based on carcass weight and PZ backfat will be herd specific and there is a need for additional predictors to PZ backfat, to improve the assessment of carcass lean content in commercial carcass classification. McPHEE, C.P. (1985). Proceedings of the 5th Conference of the Australian Association Animal Breeding and Genetics. pp. 305-306. Sydney. Department of Agriculture, North Coast Agricultural Institute, Wollongbar. 2480
