Three general formulae calibrate the average capability of marker systems to dispute falsely reported pedigree records in uniparous species. The most familiar exclusion formula applies to paternity, although the same formula applies equally to maternity. Another formula faults the relationship of a single offspring with its putative parent; for example, where the genotype of the other parent is not available. The remaining formulae excludes both of the falsely recorded parents of a substituted offspring. Simplified forms of the three general formulae facilitate the calculation of maximal average exclusion values over a range of hypothetical markers. Allele frequency data on eight marker systems in horses provide practical examples. The exclusion values of the three formulae are compared.

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Genetic size-scaling accounts for most of the variation found among mammalian species in food intake and growth rate, with food conversion efficiency independent of the body size of the species. Is the same true of breeds and strains within species?Animals from Soay, Welsh Mountain, Southdown, Finish Landrace, Jacob, Wiltshire Horn and Oxford Down sheep breeds and from a breed of feral goats were grown to 0·40, 0·52, 0·64 or 0·76 of the mean mature weight of their breed and sex. Food was offered ad libitum and individually recorded.Allometric growth coefficients were obtained for fleece weight, femur weight and femur length. Fleece was late maturing and femur early.Breed and sex size-scaling coefficients, obtained by regression of breed and sex means on mature size, were similar to those found at the species level for age from conception to slaughter, time taken to mature and food conversion efficiency. Coefficients were higher than expected for total and daily food consumption, especially at early stages of maturity. Most breed coefficients were close to expectation while sex coefficients were somewhat higher than expected.There were significant breed deviations: Welsh Mountain, Oxford Down and probably Soay sheep required less time and Jacob sheep and feral goats required more time to mature than expected from differences in mature size. Soay and Welsh Mountain sheep appeared to be more efficient and feral goats and Jacob sheep less efficient food converters over the same maturity interval.

Animals from Soay, Welsh Mountain, Southdown, Finnish Landrace, Jacob, Wiltshire Horn and Oxford Down sheep breeds and a breed of feral goats were slaughtered when 0-40, 0-52, 0-64 or 0-76 of mature body weight. The effects of stage of maturity, breed and sex were examined in the following traits: gut content as a proportion of slaughter weight; blood, omental plus mesenteric fat, perirenal fat, alimentary tract, 'remainder' of non-carcass parts and hot carcass, each as a proportion of fleece-free empty body weight; also shoulder, rib, loin and gigot joints and their commercially higher-valued (prime) and lowervalued cuts, each as a proportion of carcass weight.As a proportion, gut content declined as animals matured, as also did blood, alimentary tract, 'remainder', prime shoulder, shank and prime gigot. Increasing proportions were internal fat depots, the hot carcass, rib, loin and gigot flank. Males accumulated significantly less internal fat and more shoulder than females.When equally mature in live weight, males had proportions that were significantly lower for perirenal fat, rib and gigot and higher for shoulder and pelt plus head, feet and organs.There were significant inter-breed regressions on mature body weight. The proportion of blood, alimentary tract, pelt plus head, feet and organs, and prime gigot declined with breed size, while hot carcass, brisket, rib and loin proportions increased. These regressions were attributed to a non-random sample of breeds. The small Soay breed had proportions of internal fat and hot carcass which were well below average, and higher proportions of blood, alimentary tract and 'remainder'. Soay sheep also had a higher proportion of commercially higher-valued cuts in the carcass. In contrast, the large Oxford Down breed had low proportions of non-carcass components (except alimentary tract) and high proportions of lower-priced cuts and prime rib. Feral goats had a greater, and Southdown sheep a smaller, proportion of gut content than other breeds.

Body composition was studied in 20 mature, non-pregnant, non-lactating cows from five breeds (Hereford, Aberdeen Angus, Dexter, British Friesian and Jersey) kept on four feeding levels until they attained equilibrium body weights that were proportionately 0-7,0-9,1-1 or 1-3 of their normal adult body weight. Significant breed differences were found in the proportions of body tissues and organs and these were associated with breed differences in lactability (i.e. genetic milking potential adjusted for body size). As a proportion of body weight, intraabdominal fat, liver, spleen and uterus increased significantly with lactability and hide decreased significantly. Empty gut and gut fill also increased with lactability but not significantly. Liver proportion in dairy breeds was 1 -26 times the proportion in beef breeds. Corresponding values for intra-abdominal fat and hide were 1-43 and 0-83. The most dramatic increases with feeding level were in the proportions of subcutaneous fat, both intra-abdominal fat depots, and the udder. All fat depots were completely depleted when body weight decreased to about 0-6 of its normal adult value. Strong decreases occurred in the proportion of muscle, carcass bone and offal. The proportion of empty gut decreased significantly with increased feeding level. Liver, tail, thymus and possibly gut fill were the only traits entirely unaffected by feeding level.The near-constancy of liver proportion at equilibrium implies that the rapid response of the liver to a change in feeding level is eventually matched in magnitude by the slower responses in other tissues and organs, so that the original proportionality of about 1 kg body tissue for each 10 g liver is eventually restored.