Management
Cow Disposition
Affects Pregnancy
Rate
By Glenn Selk, Oklahoma State University
Emeritus Extension Animal Scientist
Now we have another good excuse to cull cows
due to bad temperament. Producers that routinely
breed cows artificially realize that cows that are
unruly and nervous are less likely to conceive to
artificial insemination. Presumably the lowered
conception rates were because they have been
stressed as they are passed through the
working facilities and restrained while
being synchronized and inseminated.
Research trials indicate, even
in the serenity of a natural
breeding pasture, cows
with bad dispositions
are less likely to
conceive when
mated with
bulls.
78 | JUNE/JULY 2019
Louisiana State University researchers (DeRouen
and Reger, 2007 Journal of Animal Science
Abstracts) presented data about the impact
of temperament on growth and reproductive
performance of beef replacement heifers. They
used crossbred heifers that were evaluated for
“chute score”. Heifers were scored as 1= calm,
no movement to 5= violent and continuous
struggling while in the working chute and exit
velocity. Exit velocity is a measurement of the
speed at which the heifer would travel as she
exited a working chute. “Slow” heifers (presumably
more docile) were heavier at breeding time and
tended to have a higher body condition score.
Pregnancy rate did not significantly differ between
“slow”, “medium”, and “fast” heifers when all
crossbreds were considered. However, it was
interesting to note that pregnant Brahman-
Hereford F1 cross heifers tended to have lower
exit velocities (at both weaning and at the end of
the breeding season) than their counterparts
that failed to become pregnant. These
researchers concluded that some
important relationships between
growth, reproduction and
temperament may exist
in beef replacement
heifers.