The use of liveweight change as an indicator of oestrus in a seasonally calving, pasture-fed dairy herd

Abstract

Contents: This was an observational study of 828 lactations in 542 mixed-age dairy cows that calved seasonally in a single, pasture-fed herd in New Zealand in 2008 and 2009. The study objectives were to: (i) document daily liveweight change ({increment}LW) before and after observed oestrus for cows subsequently diagnosed pregnant or non-pregnant and (ii) quantify the sensitivity and specificity of {increment}LW as a test for oestrus. The sensitivity and specificity of {increment}LW when combined with other commonly used oestrous detection methods was also evaluated. In cows that conceived as a result of service at detected oestrus, liveweight loss began 1 day before the day of detection and ..