Abstract

A study was carried out in two groups of flocks to estimate the relationship between susceptibility to facial eczema (FE) and susceptibility to nematode parasites. Faecal egg count (FEC) data on lambs born in 1989- 92 from 53 sire groups were collected on the Ruakura Romney flocks which have been divergently selected for resistance/susceptibility to FE. In addition, the Romney flocks selected at Rotomahana/Tokanui Stations for resistance/susceptibility to FEC were sampled to provide the converse (i.e. FE data) on lambs born in 1988 and 1989, and representing 43 sires. Faecal samples for FEC were collected from lambs in January and March (separated by an anthelmintic treatment) and the FEC data were analysed using a loge transformation. FE susceptibilities, using the enzyme gamma- glutamyltransferase (GGT) as an indicator, were obtained in the FE flocks at Ruakura after an oral sporidesmin challenge in May, and in the FEC flocks at Tokanui after unintentional field challenge; the GGT data were also analysed using a loge transformation. The weighted average heritabilities of loge GGT and loge (FEC+100) were 0.44

CA, Morris, NR Towers, TG Watson, M Wheeler, NC Amyes, and BC Hosking

Proceedings of the New Zealand Society of Animal Production, Volume 56, , 84-86, 1996