Weaning calves on pasture is an excellent way to keep them healthy, and minimize weaning cost and stress, because it keeps calves in a familiar environment and on their normal diet. Plus, if you're using cross-fence weaning, separation stress from their dams also is reduced.
Weaned calves will get sick only if stressed. When I was with the University of Missouri, we pasture-weaned calves for 17 years with only two sick calves out of a total of 3,900 head. That kind of success makes weaning easy.
To be successful with pasture weaning, you must ensure you have appropriate pasture for weaning. For some ranchers, their standard weaning date is when they run out of grass. That won't work for pasture weaning.
Planning makes for success
Plan to have your weaning pastures ready at least a month in advance for weaning in the humid East. In some western environments, it should be much longer if you're planning to wean on rangeland.
The most desirable weaning pastures are those with high-quality, palatable forages, preferably something calves are used to eating. For spring-calving cows, you want something that makes fresh growth in late summer and fall.
In the eastern U.S., where tall fescue dominates the landscape, either fresh or stockpiled fescue makes good fall-weaning pasture. The negative effect of fescue-endophyte infection is minimized as the forage is mostly low-toxicity leaves and the weather is typically much cooler. This minimizes heat stress.
Where available, perennial ryegrass pasture is excellent. Most mixed grass-legume pastures also work.
In the drier western half of the U.S., the aftermath on irrigated hay fields may be the best weaning-pasture option. But, be alert to the bloat potential using heavy alfalfa fields in the fall, as bloat risk increases with frost on the alfalfa.
Hay fields that are predominantly grass are adequate quality for weaned calves and safer to use. Some ranches use summer-planted winter annual forages for weaning. Mixtures of oats, awnless barley, and winter peas can work as standing or swathed forage.
Summer-rested rangeland makes good weaning forage for calves coming off rangeland. A site that's been lightly to moderately grazed in spring or early summer, and then rested for the remainder of the season, is preferable to a site that's accumulated forage all season. Spring grazing increases the amount of green forage carried through the season for higher quality, fall-weaning pasture.
Weaning fall-born calves in the spring is even easier due to the abundance of high-quality pasture that time of year. The only word of caution is to avoid endophyte-infected tall fescue for spring-weaning pasture. Toxicity increases with each passing day in the spring as seedheads develop and emerge. This can nutritionally and physiologically stress calves, increasing their susceptibility to all the normal weaning-time respiratory diseases.
In the central states where native warm-season grasses predominate, delaying weaning until the tall grasses are growing well is recommended. One advantage of fall calving followed by weaning on spring pastures is you have a built-in stocker program to increase grazing pressure during the spring flush of growth.
Once the planning's done
Once your pasture planning for weaning is completed, the next step is deciding how to use it. In some pastures, not all the standing forage is calf-quality feed; you don't want to ask them to graze everything out there.
Particularly with stockpiled fescue, we usually only expect calves to graze about a third of the available forage, and then clean up the remainder with cows. If you push the calves too hard in hopes of utilizing all the forage, their gains will drop significantly. On the other hand, they can fully utilize a perennial ryegrass pasture and perform very well.
For calves used to electric fence and regular movement, we generally move calves to a new pasture strip every 3-4 days. With calves less used to moving, we start by letting them stay 7-10 days on the same strip. If the calves don't look full every day, it's time to move them.
Pasture weaning can take a lot of the work out of weaning calves in either temperate or rangeland environments. The keys are planning to have adequate calf-quality pasture to last through the weaning phase, and allocating it as needed to keep fresh feed in front of them every day.
Jim Gerrish is a grazing management consultant based in May, ID, and former lead pasture researcher at the University of Missouri's Forage Systems Research Center in Linneus. Reach him at 208/876-4067, email@example.com, or visit http://americangrazinglands.com. Also, see his ad on page 66.