Factors affecting lamb birth weight, gestation length, survival and litter size in Poll Dorset sheep

In NSW, lamb mortality ranges between 10–35% (Hinch and Brien 2014), but this figure varies according to season, location, litter size and breed. Improving the survival of lambs is essential for industry social license and on-farm productivity. Refshauge et al. (2016) highlight the litter size effects on causes of death, with twin and triplet lambs having higher mortality rates than singles. The objective of the present research was to assess the effect of birth weight, litter size, wool length (shorn or not shorn during pregnancy), gender, conception type (artificial insemination or natural joining), on the dependent variables of birth weight, gestation length, survival, and litter size.