Death and reproductive rates of Sheep in relation to flock culling and selection

摘要

The records of a number of commercial sheep flocks, kept in such manner as permitted the collection of reliable data relating to the births, deaths, and other causes of decrement and accretion of flock numbers, have been used to compile tables of mortality, ewe and lamb survival, selection and culling factors, and similar information derivable therefrom. The number of breeding ewes #x201C;exposed to risk#x201D; totalled 83,113 and observations extended over a period of 6 years, during which 77,493 lambs were born and survived to docking, yielding a mean lambing percentage of 93.9, expressed as the number of lambs docked and marked in relation to the number of ewes mated. Ewe deaths numbered 7,042, and lamb deaths prior to 1#xBD; years of age totalled 8,056, or 10.4 of those docked.