Effect of parity on the feeding behaviour of dairy cows

The trial was carried out on Italian Friesian cows raised in an experimental free stall barn. The cows were fed once daily (TMR administered at 07:00) and milked twice daily (at 03:00 and at 15:00). During the trial 9 check points, throughout the seasons, were planned to observe feeding behaviour of cows raised in a pen equipped with 24 (1 per cow) feeding stations (Bio Control A/S). At each check point were continuously observed (per 3 days) 18-20 lactating cows for feeding behaviour parameters; finally were obtained data of 46 cows, 18 primiparous (PR) and 28 pluriparous (PL), between 50 and 250 DIM. Indexes of feeding behaviour, collected and automatically registered by the system, were number of visits, intake per visit and duration of visit. Indexes of feeding behaviour calculated were number of meals (considering the same meal when the interval between the visits was lower than 20 minutes), intake per meal, duration of meal and consumption rate. These indexes have been studied during the 24 h, in daytime (from 07:00 to 19:00) and in night time (from 19:00 to 07:00). At each check point was also recorded the individual milk yield, the TMR composition and its DM content. Primiparous had a slightly lower milk yield and a lower average DMI (19.25±2.89 vs. 20.77±3.24 kg DM/d, in PR and PL respectively). In PR, despite lower DMI, a higher number of meals in the 24 h (7.72±2.13 vs. 6.72±1.83, in PR and PL respectively) with a lower DMI per meal (2.67±0.79 vs. 3.27±0.81 kg DM/meal, in PR and PL respectively) and a lower consumption rate (96±20 vs. 118±26 g of DM/min, in PR and PL respectively) was observed. In addition a higher number of visits per day and visit per meal was observed in PR. DMI during diurnal hours was 74.61±11.69% of daily DMI in PR and 75.09±11.54% in PL, and it was concentrated after feeding distribution (at 07:00) and after evening milking (15:00). In conclusions our data show that primiparous cows need more time to chew feeds, and this should be considered important in creating feeding strategies that aim to best feed activity and stimulate intake, particularly at the beginning of lactation and when PR are raised with PL.