Do dietary and milking frequency changes during a gradual dry-off affect feed-related attention bias and visual lateralisation in dairy cows?

Abstract

A widespread management practice in commercial dairy farms is to stop milk production artificially commonly 2 months before expected calving, in a process termed drying-off. Dry-off management normally encompasses dietary changes as well as abrupt or gradual changes in daily milking frequency, which can compromise the welfare of modern cows. This study investigated the effects of various dry-off strategies comprising feed energy density (normal lactation diet versus energy-reduced diet, both fed for ad libitum intake) and daily milking frequency (twice versus once) from seven days prior to the day of last milking (i.e. dry-off day - D0) on the feeding motivation, feed-related attention bias and visual lateralisation towards feed of dairy cows. During two separate days (D-5 and D-2) prior to dry-off, cows on the energy-reduced diet started feeding much earlier than cows on the normal diet. No effect of daily milking frequency or interaction with feed energy density on feeding motivation were found. The increased feeding motivation induced by a low energy feed did not reflect changes in neither feed-related attention bias nor visual lateralisation towards feed. In agreement with the literature, the majority of the cows showed right eye dominance towards a feed source when feeding, corresponding to the left-brain hemisphere. Our study supports the suggestion that cows offered low energy diets show signs of hunger prior to dry-off, even when fed for ad libitum intake. The current study sheds light on the relevance of developing more animal-friendly dry-off management, as well as the importance of developing existing feed-related attention bias tests for nonhuman animals.