Weaning
Early Weaning Provides Boost for Young, Thin Cows
Glenn Selk, Oklahoma State University
The common tradition for weaning spring-born calves is to
wait until late October and even early November. Most mature
cows that have been feeding on adequate summer forages
will be in very good body condition, despite the pressure of
nursing a rapidly growing calf. These cows will usually be in
a body condition score of about 5 to 6 at weaning time each
fall. However, very often two-year-old cows and even some
three-year-old cows will be in marginal body condition at
the end of summer. They have a nutrient requirement for
continued growth and in the case of the two-year-old, they are
replacing baby teeth with adult teeth and are not as effective
at harvesting forage. Therefore, many of these young cows go
into the fall season in a body condition score of 4 to 5 or less.
If the rancher chooses to wait until late October to wean
the calves from these marginal young cows, there is very
little time between weaning and the first killing frost. This
is a time when a young cow could recover considerable
body condition, if she has access to a plentiful supply of late
summer, warm season grass. Without the nutrient drain of
producing and delivering milk, she can use this pre-frost
period to great advantage and replenish her own body stores.
South Dakota State examined this scenario (using mature cows)
by comparing the effect of weaning date on performance of
the beef cows. They weaned half of the cows at the time of
the first real cool spell (September 14). The other half of the
cows had their calves weaned at a traditional time (October
23). The scientists then monitored body condition and
rebreeding performance of the cows. We should note that this
study included two different nutritional levels: a low group to
mimic an early winter or a dry summer; a moderate group to
mimic more ideal summer and early winter seasons. Only the
data for those cows exposed to the low nutritional group are
presented here. They more nearly reflect what may happen for
2 and 3-year olds than will the moderately fed mature cows.
This data indicates that the 40 days earlier weaning allow
the cows to regain 1/2 of a body condition score going into
winter. More of the early weaned cows were cycling at the
start of the breeding season, conceived early in the breeding
season and should wean heavier older calves the following
year. In addition, a small amount of high protein supplement
(i.e. cottonseed meal or soybean meal) will enhance the cow’s
ability to utilize the declining quality of the late summer
forage. Therefore, this protein supplement can add more
body condition to the young cows before frost arrives. This
combination of management techniques should be a cost-
effective way to increase re-breeding rates of young spring
calving cows.
The data from the cows that were in the “moderate” group
indicate that middle-aged (4 to 7 years of age) in excellent
body condition in the fall did not significantly benefit from the
earlier weaning. I
Table 1. South Dakota study of earlier weaning on mature cows (source: Pruitt and
Momont; 1994 South Dakota Beef Report)
Weaning time
December body condition
% cycling 1st 21 days of breeding
% pregnant to 21 day AI
Average conception date
44 | OCTOBER 2018
September 14 October 23
+0.5
83
70
June 26 ---
74
35
July 3