BeefTalk: Are Your Cows Ready to Rebreed?

By Kris Ringwall, Beef Specialist


NDSU Extension Service

The question of the day: Are the cows ready to breed? For many cattle
operations, the calving season got started in mid-March, so it will be in full
swing soon.

I hope the nutritional plan is in place and the cows are doing fine. Although
nutritional adjustments can be made if needed, precalving should be a time of
contentment for the cow, so all she needs to do is enjoy late-term pregnancy.

Nutritionally, the calf is actively, maybe even aggressively, growing in utero
while absorbing the nutrition the cow is consuming and preparing for those first
moments of daylight. That daylight will happen when the pregnancy terminates
with parturition and, I hope, a live, nursing calf will greet the producer in
the near future.

Nutritionally, if the cows are underconditioned, every attempt needs to be made
to meet and improve the daily nutritional offerings. This will assure that the
calf has the opportunity to nurse good colostrum at birth and that the cow will
recover quickly from parturition, start lactating and have adequate milk to
sustain calf growth.

Unfortunately, if the cow is underconditioned, the consequences probably already
are set, which means the cow will not rebreed as quickly as she should. Keep in
mind that late gestation and lactation have a nutritional draw on the cow. From
now until breeding, feed is needed to meet the cow's postpartum recovery and
lactation needs.

In terms of days, let's look at the calendar to help understand the reality of
rebreeding cows in the beef business. If the goal is to have a cow that calved
this year on April 1 to calve next year on April 1, and assuming a gestation
period is 283 days, there are 82 days remaining to have the cow prepare to
rebred and conceive a calf for next year.

Another important point to consider is that, typically, only 72 percent of the
heifers and 60 percent of the cows calve in the first 21 days of the calving

Why is that important to know? Let's go back to the number 82. That is the
number of days the cow has to rebreed if the producer wants the cow to calve on
a desired 365-day calving interval.

If the cow is to maintain her position as the first cow to calve each year, she
has 82 days to recoup from calving, start lactating and be cycling the day the
bulls arrive in the pasture. Keep in mind that cows that are adjusted to the
production environment will maintain a 365-day calving cycle. In other words,
the cow will calve every year on time.

Cows that are poorly adapted to the production environment will not. Those cows
are utilizing whatever feed is available to recoup from calving and then trying
to start lactating and produce enough milk for the calf each day. Any thoughts
of reproducing for next year will not be entertained until those two steps are
done. That is why cows that are underfed and poorly nourished will not maintain
a good annual reproductive rate.

The producer has a very hard time making up precalving nutritional deficiencies
after calving. Thus the saying: "Cows need to fit the environment." The test for
that is the ability of the cow to rebreed and produce a calf every year at the
desired time.

There are two ways to measure this adaptability effect. The first being the
actual annual calving interval for each cow, a value that should be close to 365
days. However, that is a difficult number to collect. The percentage of the herd
that calves the first 21 days of the calving season is easier to calculate and
also will note any good or disturbing effects on reproduction within the cow

As was noted earlier, typically 60 percent of the mature cows should be calving
within the first 21 days of the calving season. Interestingly, during the last
decade of the '90s, just less than 58 percent of the mature cows were calving in
the first 21 days. Meanwhile, during the first decade of the new century, those
cows enrolled in the CHAPS program through the North Dakota State University
Extension Service were at almost 62 percent. That is a remarkable 4 percent

Something good is working in the industry. The bottom line in this discussion is
simple: Cows need to be ready to rebreed before calving. That sounds strange
but, in reality, this year's breeding success already has been determined for
the typical beef producer.

If the percentage of mature cows calving is less than 60 percent during the
first 21 days of the calving season or lower than is historically normal in the
operation, make a big note to revisit this issue next fall while the cows are
prone to adding condition.

In the meantime, start keeping a calving book and enjoy calving. 

May you find all your ear tags.

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