A Guide To Pregnancy Diagnosis - It Pays To Preg
Check Your Herd
In today's competitive marketplace where the margin between
income and cost of production is so small, it’s important
to operate a cow-calf herd efficiently. Pregnancy checking
is a critical part of a total herd management program. Cows
found pregnant are incorporated into the winter feeding program
while non pregnant or "open" cows can be culled
or fed separately to be sold later at a heavier weight or
on a stronger market. As a general rule, producers should
expect no more than 5% of their cows to be open after a 63
daybreeding season.
In some cases, a farmer with a good-looking cow or heifer
that is not pregnant is reluctant to part with her. But, if
a female has been adequately fed, properly managed and is
disease free, there is no reason she should not conceive unless
her reproductive system is not functioning properly.
Alberta Agriculture considers the cash cost of over wintering
a cow to be $250 or more. This includes feed, bedding, veterinary
fees, interest and labour. Removal of the non productive cow
in early fall will save this money and allow the producer to
select a good replacement.
There are numerous methods of pregnancy checking. The most
commonly used method is simply observing cows returning to heat.
The problem with this method is that up to 5% of pregnant cows
will continue to show bulling behavior even after they become
pregnant. The sale of just one of these cows could result in
the potential loss of a good cow from the herd. A second disadvantage
is that some open cows may not show heat until herdmates are
quite advanced in pregnancy. Three conditions that can cause
this are ovarian cysts, an infected uterus and carrying a mummified
fetus. These cows are presumed pregnant and will have been expensive
"freeloaders" since early fall.
| "Producers should expect no
more than 5% of their cows to be open after a 63 day breeding
season." |
The most reliable method of pregnancy diagnosis is rectal palpation
by a veterinarian. A trained professional can detect pregnancy
as early as 30 days after breeding while the optimum time for
diagnosis is 40- 60 days after breeding. Changes in the way
the uterus feels at various stages up to five months of pregnancy
allows the veterinarian to determine an approximate calving
date. This allows the producer to cull projected late calvers
so he is not still calving cows during spring field work. In
addition, condensed calving seasons make efficient use of labour
and result in a uniform group of calves to market at weaning
time. It is important to remember that after five months of
pregnancy, calving date estimates are not as accurate as diagnosis
at 40-60 days after breeding.
The cost of pregnancy checking is small compared to the amount
saved when it is added to a herd management program. Depending
on the type of handling facility and the number of animals to
examine, the price of this service ranges from $1.50 to $4.00
per head. A crowding pen and a narrow alley are all that is
needed to provide the necessary restraint. Most veterinarians
can process 40 cows per hour in average facilities.
Although pregnancy checking by rectal palpation is not without
its limitations, it is a quick, economical, reliable and safe
method. Pregnancy checking 40-60 days after bull removal allows
the producer to shorten his calving season and make economic
decisions about non pregnant animals. Along with pregnancy checking,
other management practices such as bull evaluation, feed analysis
and ration formulation, separate management of replacement heifers
and vaccination to prevent reproductive diseases can be adopted
to improve production efficiency. Contact your veterinarian
to help you optimize the reproductive performance of your herd.
