September 2016 Articles

Archives by Months

Importance of Pregnancy Detection

Importance of Pregnancy Detection—According to 2007-08 National Animal Health Monitoring System data, only about 20%
of beef cow-calf producers check for pregnancy in their herds. Beef cows need to become pregnant, deliver healthy calves and
wean productive calves in order for producers to make their operation economically profitable. However, every year beef
females fail to become pregnant for numerous reasons including anestrous, pre-puberty, disease (more open cows than expected
may indicate an abortion problem caused by the IBR or BVD viruses. It could also be an indicator of a sexually transmissible
disease such as vibriosis or trichomoniasis), sub-optimal nutritional management (nutritional deficiencies including a lack of
energy, trace minerals, and/or protein may delay estrus and conception due to poor egg development and subsequent
ovulation), and unknown reasons. Incorporation of timely pregnancy detection has multiple advantages for producers including
1) the ability to assess reproductive performance of their operation; 2) group cattle based on expected calving date; 3) improve
management strategies; 4) focus the correct time and labor needed during calving; 5) allow producers to take advantage of
marketing options for these animals; and 6) decrease winter-feeding costs.
The expense to maintain a cow during any given year is paid for by the calves born and weaned the following year. For example
to maintain a 1050 lbs. cow all year long currently requires approximately $1.50 per day (without labor). On a 100 head herd the
total cow costs would be $54,750. Ideally, we want to spread that cow cost over more calves sold. The more cows left open in the
herd drives up the additional revenue needed to offset the total cow costs. Building on that ideology and continuing with the
example, if we sell 100 calves at an average weight of 525 with a selling price of $157/cwt then our gross calf crop revenue will be
$82,425. Subtract our annual cow cost of $54,750 and we’re left with a gross revenue of $27,675. Now if we leave 10 open cows
in the herd and market 90 calves using the same numbers above our gross calf crop revenue will be $74,183. Subtract our annual
cow cost of $54,750 and we’re left with a gross revenue of $19,433. That is a negative impact of $8,243 for leaving those 10 open
cows in the herd. The sooner (minimum of 45 days after bulls are removed) we are pregnancy checking and making cull decisions
the more opportunity we have to decrease lost revenue.
Another important factor to remember is cull cow prices (historically) tend to be higher in the spring months than in the fall
months because of the volume of cull cows being sent to market. Determining which cows to cull early allows producers flexibility
in their marketing strategies for optimal revenue generated. Furthermore, producers that utilize early pregnancy detection on
heifers have the advantage in marketing options. They can either market open females as soon as they are identified or continue
to put weight on them and market at a later time, both allowing those females to maintain carcass quality.
Many different methods of pregnancy detection are available to cattle producers. Historically, veterinarians have performed
pregnancy diagnosis by rectal palpation. Rectal palpation can estimate the approximate stage of pregnancy and can be detected
35-40 days after breeding. This method uses the palpation of fetal membranes, position of the uterus, size of the cotyledons and
size/strength of pulse in the uterine arteries to determine pregnancy status and length of gestation. If having to use your
veterinarian to perform this service, the typical average is $4-$7 per head but could be as much as $15 per head if less than five
head.
Advancements in pregnancy detection include transrectal ultrasonography and blood pregnancy tests. An ultrasound can detect
pregnancy earlier than palpation but is more expensive, largely due to the cost of the equipment and specialized training. It can
provide more detailed information such as viability of the fetus, presence of twins and sex of the calf and it is considered
extremely accurate. Fees for this technology are typically charged at a rate of $150/hr. However, with smaller herd numbers a
producer could expect to pay $6-$9 per head. NOTE: these fees will be higher if the producer desires fetal sexing.
With a blood test (technique to measure a pregnancy associated glycoprotein (PAG) secreted by the fetus), heifers and cows can
be tested at 30 days or later after breeding but lactating cows must be at least 90 days post calving due to residual protein from
the previous pregnancy. Tests start at $2.50 per sample. The blood must be drawn and sent to a participating laboratory for
results. Disadvantages of the blood test include having to wait for results (2-3 days) compared to knowing immediately, and an
inability to accurately determine the stage of pregnancy.
While each detection method has its benefits and downfalls, pregnancy detection can have multiple benefits in any operation.
However, it is important to evaluate each technology based on the type of operation as well as that operation’s ability to access
the technology. Whichever means you choose, getting the female herd checked for pregnancy is an essential management tool
and is one of the easiest economic decisions for a cow-calf producer to make.—Jason E. Holmes, LSU AgCenter