Relationship of coat type and colour to milk production in Australian Illawarra Shorthorn dairy cattle

Abstract

An investigation of the relationships of coat type and coat colour to milk production in the predominantly red Australian Illawarra Shorthorn breed of dairy cattle has been carried out in the Kingaroy district of Queensland.

Coat type and shade of red colour were assessed in consecutive years at the beginning and end of lactation and were found highly repeatable. The correlation between each of the scores and milk yield was highly significant. The correlations at the beginning of lactation (r = –0.310**, d.f. = 235, and r = -0.287**, d.f. = 208) were not inferior to those determined at the end of lactation (r = –0.210**, d.f. = 235, and r = –0.336**, d.f. = 225 respectively). Hair diameter determined at the beginning of lactation was positively correlated with milk yield.

While these characters are phenotypically correlated with productivity, the extent of their genetic component could not be tested in this investigation.