Yellow fat in lambs caused by carotenoid pigmentation

Abstract

Abstract A survey has indicated that approximately 1 in 1000 New Zealand Iamb carcasses are rejected for export for excessively yellow fat and high incidences of 5‐10% are occasionally reported on individual farms. Phase distribution characteristics and absorption spectra of omental fat pigments from 19 lambs showing yellowness confirmed the presence of xanthophylls. Evidence is presented for a higher level of pigment in the perirenal fat than omental fat. A visual survey of 562 lambs of known parentage, backed by tintometer readings and chemical measurements on a sample of the lambs, established that the progeny of 3 Romney rams wIth Romney dams had yellower fat than the progeny of 31 other sires of 5 different breeds mated to Romney ewes. The estimated heritability of yellow fat based on the visual scores was 0.18. In general, the lambs studied had very much whiter fat than is commonly Iecorded in cattle.