VARIATION IN CARCASS AND MEAT QUALITY TRAITS AND THEIR RELATIONS TO GROWTH IN DUAL-PURPOSE CATTLE

Carcass and meat quality traits of Norwegian (NRF) dual purpose cattle were studied, and genetic parameters between these traits and growth rate were estimated. Data were recorded on 456 NRF bulls (n = 32 sires ), performance tested at test stations from 1989 to 1991. Both ANOVA a nd REML were utilised for h(2) estimations and gave about the same res ults. Carcass related heritabilities were lowest for fleshiness traits (0.05) and highest for length and fatness traits (0.55). Heritabiliti es for the meat quality traits ultimate pH and colour (Hunter-La*b) v aried from 0.08 to 0.27, while h(2) for intramuscular fat % in musculu s latissimus dorsi was estimated to 0.51. Unfavourable genetic correla tions were found between growth rate and various carcass fleshiness tr aits, and between growth rate and intramuscular fat. High growth rate was associated with longer carcasses, lower dressing %, poorer fleshin ess and a decreased m. l. dorsi area, combined with a decline in intra muscular fat content. The r(g) estimates between growth rate and light ness, redness and yellowness revealed that selection for daily gain wi ll give correlated responses of lighter, but lower colour intensity me at.