The calving season in Western Canada is primarily in late winter to early spring or January to March. Strong prices and demand in October have encouraged cow-calf producers to calve earlier in the calendar year and raise a heavier calf to market. Calving early in the year has some advantages. However, increased labour costs and adequate calving facilities due to cold weather are disadvantages which force the producer to calve out close to the farm in a drylot situation or on the same pasture that is most convenient every year. Finally, harvested or purchased feeds need to be fed for up to 100 days. However, in today’s market the cow-calf producer regardless of operation size must find ways to reduce the inputs in order to remain viable.
In March of 2007, a three-year study was initiated looking at the production and economic benefits of March versus June calving. The study is a collaborative effort between three research centres located in Saskatchewan and Manitoba. The centres are Western Beef Development Centre’s Termuende Research Ranch in Lanigan, Saskatchewan, Agriculture & Agri-Food Canada-SPARC in Swift Current, Saskatchewan and Agriculture & Agri-Food Canada-Brandon Research Centre in Brandon, Manitoba.
The objectives are to determine the effects of early (March) vs. late (June) calving on cow performance and reproductive efficiency, calf performance, environmental effects, winter and summer feeding practices, and economics of each system.
COW MANAGEMENT AND PERFORMANCE
Each calving group is managed separately. Within each system, cows were divided into two groups. They all received the same vaccinations and were managed the same as much as possible, however there were some differences in feeding because of environmental limitations at a location. Cows were weighed and measured for back fat (body condition score and ultrasound on rib and rump three times a year. Measures were taken at calving, start of breeding and weaning. Calves were weighed at birth, 60 days of age and at weaning.
In the March calving system, cows gained weight after the onset of the breeding season starting May 31, 2007, as compared to the June calving system where they lost condition from calving to weaning.
In 2007 at Swift Current, the temperatures for the months of July and August were above average (July: 18.7oC; August-17.6oC; 100-year average) and seemed to have an impact on cow and calf performance. Average daily gain (ADG) from birth to weaning for the June calving system (2.17 lb./d) was significantly lower compared to the March calving system (2.56 lb./d).
Even though calf growth rate was significantly lower for the June calving system, the weaning weights were only slightly lower compared