  BeefTalk:
Check Your Bulls as Often as You Check Your Cows
By Kris Ringwall, Extension Beef Specialist,
NDSU Extension Service
Breeding season is upon the beef industry. Although it seems like a while ago,
the North Dakota State University Dickinson Research Extension Center tested the
herd bulls for fertility April 22 and 23 in preparation for a June 1 turnout.
Not all the bulls passed and low-scoring bulls were retested. This was the first
year in a while that all the bulls tested out fine. In fact, the bulls were so
fertile, one of the teaser bulls (bulls that have their reproductive tract
altered to prevent the ejaculation of live sperm) was producing live sperm
cells.
We use teaser bulls to aid in heat detection. Because we remove the tail and
midsection of the epididymis of these bulls as calves, one would not anticipate
production of live sperm. However, this bull proved us wrong. The point being:
never assume something is so, no matter what someone tells you. Always rethink
and double check.
Other key points prior to bull turnout is continual monitoring of the bull
battery. Check and recheck your cows and bulls. Ask yourself: "In the last
seven days, how many times did I check the cows and how many times did I check
the bulls?"
How many producers really check their bulls? Is the fertility test a quick
stop at the local veterinarian on the way to the cow pasture? A lot can be
accomplished by simply assessing the "vim and vigor" of the bull.
Sometimes the cows need a flush, but the bull might also. As is often the case,
producers turn their attention to the cows.
If calving is complete, cows should be cycling. In fact, a quick check of the
cows can be made by remembering that the average estrous cycle of the cow is 21
days. If all the cows are cycling about 5 percent should be expressing
"heat" each day (one day divided by 21 days). Assume a 100 cow herd;
an average of five cows should be in heat or estrus on any given day. I realize,
not all the cows calve the first 21 days of the calving season. In fact,
typically only 58 percent of the cows calve the first 21 days of the calving
season. For typical producers who expose a mature bull to 30 cows, at least one
cow should be in heat every day early in the breeding season.
If calf gain is 2.3 pounds per day while nursing, every time a bull misses a
cow in heat it costs the producer over 48 pounds of calf. Most producers do not
argue the value of the bull, but the magnitude of that value is often
underestimated.
Not only are the genetics of a bull important but his ability to breed is
equally critical. Unfortunately, most cattle are bred out on pasture and daily
surveillance is not possible. But do stay alert.
As the second-cycle cows (those cows that calved later in the calving season)
start to cycle, the typical producer would have 27 percent of the cows calving
within the second 21 days of the calving season. If the mature bull is exposed
to 30 cows and everything is going right, 17 or 18 cows (58 percent) should have
already settled with next year’s calf in the first cycle. That leaves eight or
nine cows to breed in the second 21 day period of bull exposure.
Do the math. For the bull that was breeding at least one cow a day during the
first 21 days, the same bull during the second 21 days of the breeding season
will now only be breeding one cow every other day. In other words, the typical
bull should be half as busy during the second half of the breeding season.
Stay alert. If the bull is breeding at a similar or greater rate after being
exposed to the cows for three weeks, you have a problem. You better take a good
look at the bull bench and hope you have some depth to the team.
May you find all your ear tags.
Your comments are always welcome at www.BeefTalk.com.
For more information, contact the North Dakota Beef Cattle Improvement
Association, 1133 State Avenue, Dickinson, ND 58601 or go to www.CHAPS2000.COM
on the Internet. In correspondence about this column, refer to BT0093.
###
Source: Kris Ringwall, (701) 483-2427, kringwal@ndsuext.nodak.edu
Editor: Tom Jirik, (701) 231-9629, tjirik@ndsuext.nodak.edu
Click here for a printable PDF version of this graphic.
(5KB b&w graph)
Click here for a printable EPS version of this graphic.
(76KB b&w graph)
Click here for a EPS file of the BeefTalk logo suitable for
printing.
(100KB b&w logo)
Graphic:
Is Your Bull Settling Cows?
(1 bull exposed to 30 cows)
----------------------------------------------------------
Breeding Cows Cows in Heat Cows in Heat
Season in Heat Every 2 Days Every 2 Days
----------------------------------------------------------
(fertile bull) (infertile bull)
First 21 days 58 % 2 2
Second 21 days 27 % 1 3
----------------------------------------------------------
----------------------------------------------------------
|
