Foraging preferences of dairy cows grazing on contrasted multispecies swards

Abstract

Selective foraging has been reported in many wild and domesticated ruminants, yet modern livestock production systems rarely allow animals to express this natural behaviour. However, it is assumed that giving livestock the opportunity for forage selection positively influences their health and welfare. This study investigated the forage selection of individual dairy cows on pasture. Over one grazing season, a herd of 23 dairy cows was observed grazing on an experimental pasture in Switzerland, which consisted of different plant mixtures. The cows had unrestricted access to all mixtures and their individual foraging behaviour was documented by scan sampling. The four mixtures were rich in grasses (G), grasses and legumes (L), grasses and tanniferous plants (T), and grasses and herbs containing essential oils (E). The results revealed a partial preference for the L mixture at herd level across all grazing rotations (P ≤ 0.001). All mixtures were frequented, indicating that the herd utilized the array of available plants. Individual preferences varied and not all cows followed the herd's average pattern. Individual preferences shifted throughout the grazing season, but the pattern of this variability differed between animals. The findings demonstrate that dairy cows actively select from different pasture plants and that preferences vary between individuals and over time. Importantly, average herd preferences do not accurately represent the behaviour of all cows. Individual preferences should be considered when aiming to meet the foraging needs of all herd members.