Maternal and genetic influences on follicle and fleece development in Lincoln and Welsh Mountain sheep—a study involving egg transfer

Abstract

SUMMARYBy mean of egg transfer, lambs of a large breed of sheep (Lincoln) were born out of dams of a small breed (Welsh Mountain) and vice versa. One breed was approximately twice the weight of the other. The effects of this contrast in maternal environment upon the development of the wool follicles and upon subsequent wool production are described in this paper. These effects are compared with differences between singles and twins.Data were obtained from skin and wool samples taken at birth and at 84 days post-partum.Genetic differences were the largest single source of variation for most of the component characters of the skin and fleece.Strong maternal influences were in evidence. These were shown to have affected both Lincoln and Welsh lambs in a general (average) way and also to have had different, specific effects on each genotype as shown by genotype-environment interactions. Differences in maternal environment following egg transfer, clearly affected follicle density, primary/secondary follicle ratio, fibre medullation, fibre diameter and fibre length. Wool production was not affected, apparently because reduced follicle density was associated with increased fibre length.In the comparison between singles and twins the latter appeared to suffer a post-natal rather than a pre-natal restriction of secondary follicle development, and in the absence of extra fibre growth there was reduced wool production at 84 days.