There are many good reasons to handle stock well, and now there is one more, says Dr Lindsay Matthews from AgResearch.
Ground-breaking research in Australasia led by Paul Hemsworth at the Melbourne Animal Welfare Science Centre has demonstrated that by "sparing the rod", dairy cattle will respond with more milk in the vat.
Earlier studies had shown that the greater the number of aversive interactions between handlers and their cows, the more fearful the animals were of the handlers and the lower the total milk yield, effecting both fat and protein.
Subsequent studies utilising 131 commercial dairy farms confirmed the crucial role of handler behaviour in driving the effect on productivity. These studies compared the behaviour and productivity of cows in herds where handlers were specifically trained to handle cows less aversively with herds where there was no specific intervention. In the intervention herds, there was:
- A lower incidence of aversive human interactions with stock
- Fewer fear reactions by cows to humans, and
- Improved milk yield (about 5% during the peak months)
The effect of handling on yield appears to be mediated by stress resulting from poor handling, as cows handled aversively have higher plasma cortisol concentrations.
What types of interactions lead to stress, fear and lower production? Typically, they include human behaviours designed to force cow movement including hitting, slapping, pushing and tail twists. Other research indicates that cows perceive shouting to be as aversive as hitting, and probably contributes to stress as well. Signs that stock are unduly fearful include a reluctance to approach a human in close contact situations, and active avoidance while the handler is still at some distance ("flight distance") in the paddock.
An encouraging aspect of this work is that the productivity gains from better handling can be attained after a relatively small amount of training of handlers over a couple of visits to the farms. The key outcome of the training is to achieve a reduction in aversive behaviours and an increase in positive interactions such as pats, strokes or resting the hand gently on the animal.
