  BeefTalk:
Base Calving Season Changes on Costs, Resource Availability
By Kris Ringwall, Extension Beef Specialist,
NDSU Extension Service
Solid data is so important to answer specific questions in the beef business.
Yet, what do you do when the data needed is not available?
You do the best you can and explore what data you can. The current question
of when to calve seems to be heightening in intensity and could be termed a bit
reactionary. I am always concerned with major changes in any operation, and
shifting the calving season (to May and June?) is definitely a major change. My
current recommendation is simple, "Walk before you jump."
Delaying bull turnout assures one major point: once delayed, cows seldom
return to an early calving date unless allowed to skip a year or inundated with
nutritional inputs. Either solution means increased costs. Additional
information, or at least some encouragement or discouragement, can be gained by
observing the neighbors. One common point is a given, the masses will tend to do
what makes money over the long haul.
Economic and production forces always interact and, with time and astute
management, combine in a system that best fits local conditions. Historically,
North Dakota has been a late March to early April calving state because those
dates produce the best balance between economics and production for survival,
according to data collected through the North Dakota Beef Cattle Improvement
Association.
Chip Poland, animal scientist at the North Dakota State University Dickinson
Research Extension Center, and Jim Clement, a veterinarian from Mandan, studied
718 herd years of CHAPS data to add insight to the calving season question. (A
herd year is noted as the observation for one herd within one year.) The data
set included individual herds observed from 1994 to 1999.
One of the most notable points within the data set, was the range in average
calving dates. In the study, there were only 10 summer and five fall herd years,
indicating the difficulty in finding May or Fall calving data. For purposes of
discussion, the remaining calving seasons where late winter (115 herd years),
spring (503 herd years) and late spring (85 herd years).
Average calving date for the late winter herds was March 7, for spring herds
was April 2 and for late spring herds was April 20. The overall calving date for
these herds was March 30. Comparison of the late-winter, spring and late calving
herds found no difference in the performance of the calves. In other words, calf
average daily gain was similar, no matter when they where born.
Late-spring-born calves are lighter, simply due to age, having fewer days to
grow before weaning. The time of calving did not influence the herd size or how
the cows were culled. Late winter, spring and late spring calving seasons did
not significantly impact the number of cows culled or the reason cows were
culled from the herd or herd size. Overall reproductive performance (pregnancy
and calving percentage) was also similar for all the calving seasons. There was
a significant increase in calves born late (8.3 percent) for mature cows in late
winter calving herds compared to spring and late spring herds.
The CHAPS data showed the only disadvantage for late winter-calving-herds is
a longer calving season and the disadvantage for late-spring-calving herds was
decreased calf weight. It would appear with North Dakota that the calving season
is not a production issue. Speculation for May calving would suggest more of the
same, good calves, just lighter weight in the fall.
Because of changing nutritional status of pastures, I would not expect the
same to hold true for June calving. An actual drop in average daily gain could
be seen.
So what does matter in evaluating calving season? The evaluation needs to
focus on input costs and labor. Do you know your costs? 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 BT0138.
###
Source: Kris Ringwall, (701) 483-2427, kringwal@ndsuext.nodak.edu
Editor: Tom Jirik, (701) 231-9629, tjirik@ndsuext.nodak.edu
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Graphic --
Impacts of Calving Seasons on North Dakota
CHAPS* Producers
NDSU Dickinson Research Extension Center
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Late Winter Spring Late Spring
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Average Daily Gain neutral neutral neutral
Calf Weaning Weight positive neutral negative
Cow Reproduction neutral neutral neutral
Calving Season Length negative neutral neutral
Impact on Cow Culling neutral neutral neutral
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*Cow Herd Appraisal and Performance Software Program
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