Evaluation of oestrus detection efficacy and accuracy by three methods in a confinement or pasture management system with Holstein–Friesian cows

The objective of this experiment was to compare the efficacy of three methods of oestrus detection [visual observation (VO), tail paint (TP)and radiotelemetry-HeatWatch® (HW)] in two management systems[cubicle housing with a total mixed ration(HOUSED) and rotational pasture with concentrate supplementation (GRASS)]. The 46 randomly allocated and blocked, spring-calving Holstein-Friesian cows were monitored by the three oestrus detection methods simultaneously from ten days postcalving for nine weeks on the same farm. The occurrence of nine selected behaviours associated with oestrus was also recorded during the thrice daily 20 minute visual observation sessions. Thrice weekly milk sampling for progesterone analysis (EIA) was used to determine the dates of true standing oestrus events (oestrus detection accuracy). Data were analysed by proc Frequency, Genmod, Npar1way, Ttest and Univariate, as appropriate, in SAS. All three detection methods had a higher oestrus detection efficacy in the GRASS (VO 59, TP 65 and HW 69%) compared to the HOUSED treatment (VO 20, TP 26 and HW 37%)(P