Environmental Factors Affecting Body Dimensions in Yearling Hampshire Ewes

Abstract

Body measurements and simple ratios of these measurements taken on yearling ewes from the University of California Hampshire sheep flock over a period of 17 years, were studied to learn the importance of certain known environmental differences in determining body size and conformation. In the group studied, older animals were found to be significantly larger than younger ones in body weight, heart girth, round measurement, chest width and depth, loin width and in the ratio of heart girth to withers height and chest depth to withers height, but not in withers height or the ratios of chest width to heart girth or chest depth. More-inbred animals were smaller than less-inbred ones in weight, heart girth, round measurement, chest depth and width, loin width and in the ratio of chest depth to withers height, but not in withers height or other ratios. Singles were larger than twins in all individual measurements studied except chest depth. Singles were higher than twins in the ratio of chest width to depth but not in other ratios. The offspring of 2-year-old dams were not significantly different from others in any of the measurements or ratios studied. Data were adjusted to single, non-inbred status and to the average age of 440 days, using the estimates calculated. The means and within-years standard deviations for these data are also reported. It is concluded that both body size and conformation are affected to an important extent by the factors studied.