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Published online by Cambridge University Press: 27 March 2009
Left and right 9–10–11 rib joints from 104 Madura, Ongole, Bali, Grati (or Friesian cross) and buffalo bulls were dissected into bone, muscular and fatty tissues and then ground and chemically analysed for water, ash, ether extract and protein contents. The carcasses from 48 of these bulls were also ground and analysed for these same chemical components. Within-breed relationships between dissectible and chemical composition in the rib and between dissectible composition of the rib and chemical composition of the carcass were tested by regression analyses.
There were no breed differences in the relationships between bone and ash or between muscle and protein in the rib, but at the same content of rib fatty tissue, buffaloes had less predicted rib ether extract than Bali, Ongole or Madura cattle. At the same ash content of the rib, Madura bulls had the most carcass ash. Rib-muscle content was considered to be a poor predictor of carcass protein. At the same fat content of the rib, breed differences in predicted carcass ether extract were large with Grati having higher levels than Bali and all four cattle breeds having higher levels than buffaloes. Use of rib-fat or rib-energy contents to predict carcass energy yielded relative breed differences similar to those when rib fat was used to predict carcass ether extract.
Differences in the distribution of fat within the carcass, particularly in the subcutaneous fat depot, were considered to have a major bearing on differences in the within-breed relationships. Therefore, published part-whole prediction equations should be used with caution when comparing genotypes likely to differ in the distribution of tissue within the carcass.