Preparing for outwintering
We've long known that cattle can survive, even thrive, with minimal use of barns for shelter during the winter season in Minnesota. Beef cows and older dairy heifers have been routinely assigned to outdoor housing. Milk cows have generally been kept indoors, in part because cows were milked in housing stalls, although curtain-sided free stall barns have become the standard housing of new construction for the larger herd. While outwintering is gaining popularity with lower input grazing herds, the practice must be undertaken with the awareness that success requires some changes in management. In addition, a plan is needed to cope with the extremely hostile weather that can strike during winter.
An outwintering site needs: a secure perimeter; to be accessible for observing, feeding and safely moving cows to and from milking; to provide shelter from winter winds where a bedded pack can be established; to allow for snow removal and ice management; to provide a supply of drinking water; and to prevent run-off from entering lakes and streams. Many farms have such a site with wind protection provided by trees, but some farms will need to construct windbreaks and make other adjustments. If the site is exposed, a contingency plan for storms is needed. The muddy conditions of autumn and spring can be minimized by feeding on pastures when the surface of the outwintering site isn't frozen. Compact outdoor bedded packs will keeps cows clean with 11 to 13 lbs of dry small grain straw if cows are closely monitored for cleanliness Less straw has been required to keep cows clean and dry on outdoor pack than with loose-housing in a shed at the West Central Research and Outreach Center (WCROC), Morris. Greater amounts of corn stover bedding may be required. If you are inexperienced but considering outwintering, it pays to visit farms that have successfully outwintered their herds.
Bales set to be fenced for outwintered heifers.
Vulnerability of animals to harsh winter conditions varies with age and size, and general health and body condition going into winter. Dry cows and yearling heifers will adapt through the autumn by growing a thick fluffy hair coat as they continue to consume stockpiled pasture during autumn and into winter. Wet, muddy lots should be avoided, as they are hotbeds for coccidiossis and wet matted hair coats that provide poor insulation. Thin animals of any age may have trouble holding their own if housed outdoors during winter. Spring calves born March through May can be outwintered if smaller or weaker calves are sorted for more conventional housing and adequate supplementation is provided. If the younger animals are accustomed to confinement, they will also need training to adapt to outdoor housing, but most learn quickly if experienced animals are added to the group. During winter, frozen teats are a concern. Frostbite most often occurs to fresh animals with congested udders and wet teats exposed to extreme cold. During coldest conditions, teats of cows at WCROC are wiped dry before leaving the milking center.
As ambient temperature decreases, the proportion of a cow's diet utilized for maintenance increases and she increases intake to meet her energy needs. During January '05 and '06 at WCROC, outwintered cows consumed 3.9 to 4.3% of body weight as dry matter from the TMR while producing 52 to 55 lb of milk per day, and gaining weight and condition in late lactation. Breed of cattle has an impact on feed efficiency in winter. Holstein steers required more feed/gain than beef breeds in feedlot comparisons at WCROC. Outcomes were attributed to less hair coat, fat insulation, and higher maintenance requirements of dairy animals. Dry cows and heifers with condition scores of 3.5 wintered on unbedded pasture. However, with wind protection from an irregular landscape and access to a woodlot during storms, they gained 1.5 to 2.0 lb/day when consuming 2.6% of body weight as dry matter from corn silage, hay, and 5 lb grain. Breeding heifers of 800 lb consumed 2.8% of body weight. Outwintered spring calves weighing 450 to 550 lb or the younger weaned calves in a shed ate 3.1% of body weight as dry matter. Calves are well known to grow well in hutches with some adjustments to intake in the cold, but calves less than 80 lb birth weight must be monitored carefully in cold weather.
Outwintering is working well for low input dairy farmers. Investments in buildings are reduced, although some of the economies are offset by lower milk production and increased energy requirements. A contingency plan to provide for safety of people and animals during the foulest of weather conditions is needed.
Published in Dairy Star October 28, 2006