The influence of sires on lamb survival

T.W. Knight, G.K. Hight and G.W. Winn

Whatawhata Hill Country Research Centre, Hamilton and Ruakura Agricultural Research Centre, Hamilton

Proceedings of the New Zealand Society of Animal Production. 1979, 39: 87-93

Significant differences among sire groups were found in survival to weaning of multiple-born lambs in the Waihora Lands and Survey flock in 5 out of 7 years. Similar differences were observed in single-born lambs, but the number per sire was too small for the differences to be significant. The survival rates of the lambs were not related to their sires' selection index nor to components of this index (ie. dam's fertility index, ram's own weaning weight, hogget body weight and hogget fleece weight) except in 1977, when there was a relationship with hogget fleece weight.

Groups of rams, selected for high and low progeny survival on the basis of past performance, were single-sire mated to 120-125 randomly selected Romney ewes at Whatawhata in 1976 and 1977. There were no differences in 1976 between the two groups of rams in the survival of their progeny, but in 1977 lamb survival was 8% and 17% higher respectively for single- and twin-born lambs sired by the high progeny survival rams. The higher survival in single-born lambs was due to a lower incidence of dystocia, possibly caused by the lower birth weights and head circumferences of the high survival rate rams' progeny.

Keywords: NZSAPAB;

Last Updated 12-09-1998