FR Barnes; JL Donaldson
Abstract
An account is given of the rearing in one unit of 274 Friesian, Jersey, and Friesian-Jersey-cross male calves and of their subsequent growth to approximately 22-23 months of age. A sample of the 10 heaviest of each breed group was selected for slaughter at 22-23 months of age. The Friesian steers in this sample were 6.8% heavier than the Jersey steers. Their heavier carcass weight and higher grades gave them a monetary advantage of $NZ9.42 over the average Friesian-Jersey-cross carcass and an advantage of $NZ32.36 over the average Jersey carcass. The proportional composition of boneless, fat-trimmed meat, fat trimmings, and bone in the side did not differ between breed groups. However, the proportion of hindquarter boneless, fat-trimmed meat to total meat in the side was significantly lower by 1.1% for the Jersey group and by 0.8% for the Friesian-Jersey group compared with the Friesians. The boneless, fat-trimmed meat production per day of age was highly significantly different at 0.12, 0.09, and 0.11 kg for the Friesian, Jersey, and Friesian-Jersey-cross groups respectively. The fat of the Jersey group of carcasses was more yellow than that of the other two breed groups, but some carcasses in the Friesian-Jersey cross group also had yellow fat (Morgan & Pickering 1969). The intensity of fat colour was lost during a 48-h chill of the carcasses. The kidney and channel fat were heavier proportionately in the Jersey group. These two fat depots in the Jersey and Friesian-Jersey-cross groups were significantly heavier in the right side than in the left side of the carcasses. It was concluded that the Friesian and Friesian-Jersey-cross cattle would be satisfactory for production of boneless, fat-trimmed beef for hamburger and sausage-like products. Jersey steers in contrast grew too slowly and when slaughtered at 22-23 months of age their carcasses were too light. Some carcasses of this breed group could be downgraded because of yellow-coloured fat. Therefore it is not recommended that Jersey steers should be considered by farmers for this kind of beef production.
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