The effect of temperature and humidity on daily milk production and milk composition for four breeds of dairy cattle at Darwin

Abstract

The influence of components of the environment on daily production of milk and milk constituents in a tropical monsoonal climate has been investigated. The components relative humidity, maximum temperature, and derived joint estimates of those two variables; namely, a direct interaction term, and a temperature-humidity index (THI) have been studied. Daily milk yield and composition parameters for individual animals of four breed groups: Australian Milking Zebu (AMZ), Australian Friesian Sahiwal (AFS), Holstein-Friesian (HF) and Illawarra (IL) have been measured. These breeds represent varying degrees of Bos indicus content from 50% (AFS) to 0% (Holstein-Friesian and Illawarra).