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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. Biometrika Trust is collaborating with JSTOR to digitize, preserve and extend access to Biometrika. SUMMARY Methods for generalized linear models are extended to provide estimates of location and variance parameters for mixed models fitted to binomial data formed by classifying samples from an underlying normal distribution. The method estimates the parameters directly on the underlying scale. For a balanced one-way random effects model, the variance estimator simplifies to the usual analysis of variance one. The estimation of variances and the prediction of random effects for binomial traits is required by animal breeders. The predictors given are analogous to best linear unbiased predictors (Henderson, 1973) but differ from those presented by Harville & Mee (1984).

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A comparatively rapid method for estimating the chemical composition of mutton carcasses has been reported previously (Barton & Kirton, 1956 and a detailed description of the procedure has been given by Kirton & Barton (1958). The method involved the cutting of a frozen carcass down the back-bone. One side was then sliced and the slices, consisting of frozen flesh and bone, were ground (minced) in a commercial grinder (mincer). Samples were drawn from the thrice-ground material and these were analysed chemically. Treatment differences between groups of carcasses have been detected using this procedure, but hitherto it was not possible to study the magnitude of any errors inherent in the method. MATERIALS AND METHODSTwenty Southdown-Romney cross wether lambs which had been used in an investigation into the effects of cortisone and hecogenin on wool growth and live weight were available for carcass analyses. No differences of any importance due to the effects of the drugs were observed on live weight or in carcass composition of these lambs; hence they were suitable for the present study.At slaughter the animals had an average live weight of 78 lb. (range 63-5-93-8 lb.) and their hot carcass weight averaged 39-2 lb. with a range of 31-2-43-8 lb. Slaughtering and dressing followed commercial practice; thus each carcass was headless and the bones of the lower limbs from and including the metacarpals and metatarsals were removed. The kidneys were removed but the perirenal fat was left intact in the carcass. The carcasses were placed in a chiller overnight and then they were frozen and stored until required. Following approximately a year of storage the frozen carcasses averaging by then 36-6 lb. in weight were brought in twos and threes to the meat laboratory for analyses.These carcasses while still frozen were divided down the back-bone using a meat band-saw, then each side was cut into four parts, namely, leg, loin, rib cut, and fore. (a) Jointing of a sideAll jointing was done with a band-saw. A cut was made between the last thoracic and 1st lumbar vertebrae and the rib (usually the 13th) was followed out to the flank. The loin, including all perirenal fat, was removed from the posterior part of the carcass by cutting between the last lumbar and the 1st sacral vertebrae and continuing this cut at right angles to the back-bone through to the flank. The loin contained six or seven vertebrae. In cutting at right angles to the back-bone a small tip of the ilium was invariably severed and this became part of the loin. The part designated as the leg comprised the remainder of the posterior portion of the side and thus included the greater part of the pelvis.The rib cut, consisting of the 9th, 10th and 11th ribs, was removed from the anterior portion by cutting midway between the 8th and 9th ribs and midway between the 11th and 12th ribs. The cuts were made from the back-bone through to the flank, but because of the necessity of cutting midway between the ribs it was not always possible to commence the cut between the app...

Carcass characteristics of Southdown rams from lines selected for high or low backfat depths (assessed ultrasonically at Position Cover the longissimus dorsi muscle at the last rib) were compared. Rams were 15-18 months old and average carcass weight was 29.5 kg fo{ the High-line (n = 36) and Low-line (n = 42) groups. When adjusted by covariance to the same carcass weight, animals from the High-line had higher dressing-out percentages, lighter weights of several internal organs, and shorter carcasses. At a constant side weight, the High-line sides contained 18% more dissectible fat and significantly lighter weights of muscle and bone. However, muscle to bone ratio and muscularity in terms of muscle weight per unit length were greater for the High-line group. The High-line carcasses contained a greater proportion of their weight in the rack and loin cuts. The greater weights of four dissectible fat depots in the High-line carcasses were the result oflarger rather than more adipocytes. The results show that selection on the basis of a single fat depth measurement resulted in significantdifferences in all measures of fatness, and also in several other carcass characteristics.