Weaning time is harvest time in cow-calf country. This can be a stressful time for the cow, the calf and the rancher. Probably the most critical weaning decisions a rancher needs to make are gauging when and where to wean.
USDA's National Animal Health Monitoring System (NAHMS) reports that the average weaning age of beef calves in the U.S. is a little over seven months of age. Over three-quarters of these producers reported weaning calves between 5½ - 8½ months of age.
The interesting part of the NAHMS survey is that producers reported a lack of flexibility in selection of weaning time. Relatively few ranchers indicated that cow condition, forage availability or market price drove the decision of when to wean calves.
The objective of a weaning program is to get the calves separated from their mothers and on their own as efficiently as possible. This should be when lactation declines and calf gain begins to decrease.
Diets for weaned calves can be purchased or ranch-developed. The advantage to purchased feeds is they're more likely to be balanced for energy, protein, fiber and minerals. In addition, many of them can contain medications or ionophores recommended by a veterinarian or nutritionist.
Some important considerations in weaning management include:
Dust - Dust causes severe irritation to the respiratory tract. Sprinkle pens to keep dust down.
Heat - Cattle tend to hold their body heat through the day, so if it's hot, try to work them in the morning as opposed to the afternoon or evening.
Bawling - This is another irritant to the upper respiratory tract. To minimize bawling - unless “fenceline weaning” - separate the calves from the cows so they can't hear each other.
Dehydration - Some calves are not acquainted with water troughs and are so busy bawling they don't take time to find the water and drink. Use of a water source similar to one they may have been around may help.
Feed change - A change in diet requires the growth of different organisms in the rumen to digest the feed. This change can take up to two weeks.
Why is stress the most important challenge to overcome when weaning calves? The University of Minnesota's Bethany (Lovaas) Funnell, DVM, explains that stress causes the release of the hormone cortisol - a catabolic steroid that has negative effects on the immune system.
This not only makes a calf more susceptible to respiratory disease, but decreases the calf's ability to respond to a vaccine. Because of this, it's important to get the first dose of vaccine into the calves while they're still nursing, when stress levels are low.
There are two major groups of vaccines that should be considered to assist weaning - those for clostridial diseases and those for respiratory diseases. If you're unsure which vaccines to use, contact your herd-health veterinarian.
There are about as many weaning strategies as there are ranchers. Over the past 10-15 years, the beef industry has become more aware of the value of pre- and post-weaning calf health management and marketing management. It's worthwhile to explore the various “cookbook” weaning programs and regimes available.
One concept that's been getting a lot of attention is fenceline weaning, which allows cows and calves to have several days of fenceline contact, but calves are unable to nurse through the fence. This requires adequate facilities to allow for feeding and watering the calves, and the fence must be tight enough to prevent the calf from getting back in with the cow.
Early weaning is a management practice sometimes used during drought conditions, or when forage quantity is less than desirable. Early weaning is often used to improve cow condition for rebreeding, particularly when forage is limiting. Research shows mixed results on the economics of early weaning.
Extended weaning may make sense in times when feed costs are high and when grazing forages aren't a limiting factor. A Florida study shows that fall-calving cows can nurse calves for up to two months beyond a standard weaning age of 7-8 months and significantly increase calf weaning weight without affecting cow reproduction.
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