A study of the lactation and growth of hill sheep in their native environment and under lowland conditions

Abstract

1. A method is described suitable for the estimation of the milk yield of sheep under natural grazing conditions.2. The yields obtained from Welsh Mountain sheep in two environments are shown.3. A close but diminishing relationship is shown to exist between the milk yield of the ewe and the growth of the lamb. Evidence is given of the effect of milk yield at later stages.4. The estimation of the ewe's milk yield from the weight of the young lamb is discussed. These estimates are used in conjunction with actual milk records in the present study.5. The ewe's milk yield is shown to be significantly related to nutrition, body weight, udder size and the lamb's birth weight.6. The relation of milk yield to weight gain during lactation, fleece weight and fleece type were mainly non-significant.7. From the limited data available, it seems that milk yield has a fairly high repeatability and heritability.