“In Defense of Early Weaning”
by Chris Reinhardt, feedlot specialist
Although most areas have gotten a reprieve from the 2011 drought, others are still feeling the lingering effects of low rainfall and high feed costs. Early weaning is an effective way to save on summer pasture and preserve cow body condition going into the winter. In fact, early weaning may be worth considering every year regardless of summer pasture conditions.
The rumen of calves begins to develop at the very first opportunity to consume solid food. Although calves rely on milk as their primary nutrient source as long as the supply is abundant, they will also begin to graze alongside their dam at only a few weeks of age. You will often observe calves grazing very close to their mothers’ heads, sampling the exact same grasses as their mother as she teaches them what to eat and what to avoid.
The grass that is consumed early in life enters the rumen and begins to be fermented by bacteria which the calf picks up from its mother and the world around it. As this fermentation progresses, and the calf supplies increasingly greater quantities of grass, the rumen grows in size and develops papillae, or finger-like projections, which aid in nutrient uptake from the rumen. So the suckling calf is actually a fully functioning ruminant by 90 days of age.
In addition, the 6-7 month age window may actually have disadvantages compared to weaning at a younger age. The passive immunity provided by colostrum remains active for 3-4 months but then wanes, after which time the calf must rely completely on its own immune system. But in many cases the immune system is not fully competent to battle all pathogens which attack the newly weaned calf: viruses, bacteria, dust, internal parasites, etc. So it is possible that the 90-day old calf may have an immunological advantage to the 205-day old calf in battling pathogens.
Weather also plays a large factor in weaned calf health. If we could guarantee sunshine and moderate temperatures throughout the fall weaning season, calf health would not be an issue. But, unfortunately, the combination of cold temperatures, precipitation, wind, and mud in the fall further suppresses an already incompetent immune system—a perfect recipe for respiratory disease.
Finally, the elimination of milk production after weaning allows the nutrients consumed by the cow to go back into rebuilding body condition. This could result in substantial reductions in winter feed requirements because (a) nutrients harvested by the cow are nearly always lower cost than feeds harvested and transported to the cow, and (b) forage quality in late summer and fall is nearly always greater than during the winter.
The 2011 taught that it pays to be prepared for all possible eventualities in the cattle business. Although there are some complicating management considerations, early weaning can save on pasture forage, preserve cow body condition, and improve post-weaning health of the calf.
