Whole lactation feeding behaviour of Simmental cows in commercial dairy farms

Understanding the changes that occur in dairy cows during lactation may be important to better manage the herd and optimise production. Nowadays, thanks to the spread of new technologies in commercial dairy farms, it is possible to obtain numerous individual data throughout its productive career. Using daily data collected with sensors available in commercial farms, we investigate the relation between feeding behaviour, parity, and performance in Italian Simmental dairy cows. The main aim was to better understand how lactation affects cows feeding behaviour. Individual data on milk performance, eating time (ET), rumination time (RT), and body weight (BW) from 80 dairy cows during the whole lactation were collected for 12 months. Animals were divided into two groups considering parity (primiparous, PP, and multiparous, MP) and three feeding behaviour classes from low to high values (eating time classes, ETC; rumination time classes, RTC). Data was statistically analysed with a factorial design with animals as repeated measurements. ETC is positively related to milk composition, as animals in the higher ETC are more productive, especially at the two ends of the lactation curve (p < 0.01). An interesting relation between ET and RT was found. Milk production is also positively related to RTC, but surprisingly, no effect was found on milk fat (p > 0.05). As expected, a positive relation between parity and milk production was found (p = 0.002), but no differences were found in milk composition or somatic cell count between the two parity groups. PP cows have greater eating activity but lower estimated dry matter intake than MP cows (21.85 vs. 23.43 kg/d, p < 0.001), which meet their requirements with an increased eating rate (105 vs. 89 g/min, p = 0.002) and a tendentially higher RT (525 vs. 506 min/d, p = 0.015). All this information can be combined and integrated to provide valuable support to the farmer in managing the herd.