Aggressive defense of the calf by beef cows can result in serious and fatal injuries to producers, veterinarians and members of the public. This risk is likely to be exacerbated by the further extensification of pasture-based systems, the increasing use made by the public of agricultural land for recreation and the need for increased handling of the calf to comply with EU ear tagging regulations. Selection for reduced flightiness from humans during routine husbandry tasks is being investigated in some countries and interest in selecting for stronger maternal behaviours to suit low-labour input systems is emerging. A potential consequence of these selection approaches could be to inadvertently select cattle that aggressively defend calves against human approach with an associated increase in risk of human injury. This article assesses the potential for correlated changes in maternal defensive aggression resulting from selection on flightiness and calf survival or maternal care traits and examines the scope for including maternal defensive aggression as a trait in its own right in selection indices. Evidence is presented which shows a phenotypic relationship indicating that both reduced flightiness and strong maternal care are associated with elevated maternal defense in several species. Selection for the former traits could lead to undesirable changes in maternal aggressiveness to handlers if confirmed at the genetic level in cattle. Maternal defensive aggression is weakly, but significantly heritable in beef cattle. Selecting cattle intermediate in expression of fear and maternal care or including selection against aggressiveness itself in breeding programmes may benefit handler safety.
- Maternal aggression