Management
University of Florida animal scientists recorded
disposition scores over two years on 160 Braford
and 235 Brahman x British crossbred cows.
They wanted to evaluate the effects of cow
temperament and energy status on the probability
to become pregnant during a 90-day natural
breeding season. Cows were scored as 1= calm,
no movement to 5= violent and continuous
struggling while in the working chute. Also,
a pen score assessment was assigned as 1=
unalarmed and unexcited to 5 = very excited and
aggressive toward technician. An exit velocity
speed score was measured as the cows exited
the working chute as 1= slowest and 5 = fastest.
An overall temperament index score was
calculated by averaging the chute score, pen
score and exit velocity score. Blood samples
were analyzed for cortisol concentrations.
80 | JUNE/JULY 2019
Cortisol is a hormone released when mammals
are stressed or excited. Increased cow
temperament score and elevated plasma cortisol
concentrations both were associated with
decreased probability of pregnancy. These results
suggest that excitable temperament and the
subsequent elevated cortisol concentrations are
detrimental to reproductive function of cows.
These authors concluded that management
strategies that improve cow disposition, enhance
their immune status, and maintain the cow
herd at adequate levels of nutrition are required
for optimal reproductive performance. LT
Resource:
Cooke and co-workers. 2009 Florida
Beef Research Report.