Distribution of litter sizes within flocks at different levels
of fecundity
G.H. Davis, R.W. Kelly, J.P. Hanrahan, R.M. Rohloff
Invermay Agricultural Centre, Ministry of Agriculture and
Fisheries, Mosgiel
Proceedings of the New Zealand Society of Animal Production.
1983, 43: 25-28
Proportions of ewes having 1 to 4 lambs in 72 local breed flocks
with mean litter sizes per ewe ranging from 1.07 to 2.30 were examined,
and compared with the proportions recorded in 12 groups of Booroola and
8 groups of Finn type ewes. Below a mean litter size of 1.70,
differences in litter size resulted from differences in the proportion
of ewes having singles and twins. Mean litter sizes ranging from 1.70
to 2.30 were accompanied by changes in the proportions of ewes having
singles and triplets, the proportion of ewes having twins or quadruplets
showing no significant change. The proportions recorded in local breed
flocks and groups of Finn-type sheep were similar over litter sizes of
1.70 to 2.30. Groups of ewes that carried 1 copy of the Booroola gene
had more ewes with 1, 3 and 4 lambs, but fewer ewes with twins, than the
local breed flocks.
Keywords: NZSAPAB;
Sheep; ewes; little size; Booroola; Finn
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Last Updated 03-05-1997
