Effects of feeding frequency and environmental conditions on dry matter intake, milk yield and behaviour of dairy cows milked in conventional or automatic milking systems

The aim of the study was to investigate the effect of feeding frequency on milk production, dry matter intake (DMI) and cow behaviour on two dairy farms with conventional and automatic milking systems (AMS) in different environmental conditions. Cows on two farms were monitored. On the first farm, 96 primiparous cows were milked in a herringbone parlor while on the second a group of nearly 50 cows were milked in two AMS with a forced traffic. On each farm, treatments consisted of two different frequencies of total mixed ration (TMR) delivery (2 vs 3 on the conventional farm; 1 vs 2 on the AMS farm) replicated in two different periods of the year with THI of 72.6 and 60.7, respectively. The behaviour of the cows was monitored by continuous video recording. Statistical analysis was performed separately for the two farms. Increasing the frequency of TMR deliveries did not result in any variation in DMI but significantly improved milk yield on both farms. The increase in feeding frequency at the bunk in the AMS farm mitigated the negative effect of hot conditions on production with a 7.6% increase in milk yield. Feeding frequency did not influence cow behaviour on either farm. Hot conditions showed a depressive effect on DMI (nearly 8% on both farms) compared with thermoneutral conditions but caused a reduction in milk yield (an average 17%) only on the farm with multiparous high-producing cows milked automatically. In the hot period, cows on both farms showed a reduction in daily lying time and an increase in daily standing time.