Some observations on an outbreak of hogget ill-thrift

Abstract

An outbreak of hogget ill-thrift in the late summer and autumn of 1965 on a pasture of perennial ryegrass is described. Hoggets on an adjacent pasture of white clover showed no symptoms of the disease.

Two features of the outbreak differed from the typical characteristics of the disease: first, the hoggets with ill-thrift showed no signs of inappetance; and, second, there was no autumn flush period of herbage growth.

Results of yield determinations and chemical analyses of total nitrogen, non-protein and nitrate nitrogen, total soluble sugars, cellulose, and lignin of the perennial ryegrass pasture could not account for the severe and prolonged failure of the hoggets to gain weight.

It was concluded that in future ill-thrift studies it would be of value to observe the grazing behaviour of affected animals, to measure rather than observe herbage growth, and to take account of the possible effects of sub-clinical infestations of internal parasites.