DAIRY COWS' FEAR OF PEOPLE REDUCES MILK YIELD AND AFFECTS BEHAVIOUR AT
MILKING
Jeffrey Rushen, Anne Marie de Passille, Agriculture and Agri-Food Canada,
Lennoxville, Canada. Lene Munksgaard, National Institute of Animal Science,
Foulum, Denmark.
We examined how cows' fear of people affects milk yield and milking efficiency.
Lactating cows (14) were each handled by two people. One handled the cows
gently (brushing or offering food) while the other treated them aversively
(hitting or occasional use of a cattle prod). After 12 aversive and 12
gentle treatments over 3d, the cows stood further from the aversive than
from the gentle handler in a standard test (P<.05). Thus, the cows could
distinguish between handlers and had learned to associate the treatments
with a specific person. During 4 milkings, at intervals of 2-3 d, we recorded
duration of milking, milk yield and behaviours affecting the efficiency
and safety of milking. After milking the cows were injected i.v. with oxytocin
and re-milked. During two milkings either the gentle or the aversive handlers
stood in front of the cows. During two other baseline milkings the handlers
were not present. The presence of the gentle handler did not change milk
yield or residual milk compared to the baseline milkings. The presence
of the aversive handler reduced milk yield by 10% compared to the baseline
milkings, and doubled residual milk compared to the baseline milkings and
to when the gentle handler was present at milking (P<.05). The presence
of both handlers decreased the amount of kicking (P<.05). Duration of
udder preparation and incidence of detachment of the milking machine were
not affected. Dairy cows' fear of a specific person, who is present at
milking, can substantially reduce milk yield, possibly by reducing oxytocin
secretion, but may not make the cows more difficult to handle at milking.