Ralph Cator

Early vs. LateCalving
The effect of spring or summer born calves on a farmer’s bottom line.
By Debbie Lockrey-Wessel
M
any factors affect cattle
performance and impact a
farmer’s bottom line. We often
think of things like weather and feed,
and how much a calf gains before going
to market. Now scientists are discovering
that the season in which a calf is born
can impact the bottom line as well.
To help farmers in Western
Canada make an informed decision,
a collaborative project is underway
involving scientists from Agriculture
and Agri-Food Canada (AAFC) and
the Western Beef Development Centre
(WBDC). The project will be completed early in 2011 and
involves Dr. Shannon Scott and Dr. Hushton Block of AAFC’s
Brandon Research Centre in Manitoba, Dr. Alan Iwaasa at
AAFC’s Semiarid Prairie Agricultural Research Centre in
Swift Current, Sask., and Dr. Bart Lardner at the WBDC in
Lanigan, Sask. These scientists have joined forces to examine
how early versus late calving under western Canadian
conditions can affect the economics,
labour requirements and energy use
efficiency of cow-calf production.
In Saskatchewan, late calving is not a
very common practice – only about 10-
15 per cent of producers are currently
calving in the summer. However, some
producers may want to move their calving
season later to take advantage of reduced
labour requirements or may want to
match the cow’s feed requirements with
the available feed resources.
“We’re trying to look at the impact
of matching the feed resources that
are available at different times of the year with the cow’s
nutritional requirements,” explains Dr. Iwaasa. “Beef-cow
feeding is 60 to 70 per cent of the total cost of production
and the cow’s highest nutrient demand is 30 to 90 days after
calving. How the cow takes in nutrients and processes those
nutrients will also impact the calf’s growth. What we’re
trying to do with a later calving season is work with Mother
Nature.”
“The May and June period is when pastures are starting
to grow and you have the most forage production in the
pastures,” he adds. “And that is also the same time when a
cow has the greatest nutrient needs. Forages are used most
efficiently when the nutrient requirements of the cow are
matched with the nutrients available from forages. So we’re
trying to just match those up.”
While similar studies have been conducted in the United
States, in places like Nebraska and Montana, and under
Canadian conditions in Ontario, the conditions in Western
Canada are quite different.
“In Western Canada, where the bulk of the Canadian cowcalf
herd is located, the climatic conditions, the types of
feed that we have, and the marketing systems are all quite
different,” explains Dr. Lardner. “We wanted to be able to
provide the information to beef producers here who may
be thinking about making a transition from early calving
system, which would be somewhere around March and April,
to a later calving season, which would be more like May and
June.”
Previous Canadian studies from Alberta showed no
difference in calving and weaning rates, but lower birth
weights for the early calving group compared with the late
calving group, while studies from Ontario show heavier
cow weights for the late calving group. Since Manitoba and
Saskatchewan are physically located in the middle of the
two Canadian studies, scientists needed to determine if the
results from the other Canadian studies are applicable in
these prairie provinces.
To determine this, Drs. Iwaasa, Scott and Lardner
launched a three-year study, beginning in January 2007
with the first early calving season and ending in December
22 Canadian Meat Business September/October 2010 meatbusiness.ca