by Sally Colby
For farmers grazing cattle in an organic system, winter housing is an important consideration. Many farmers are choosing to outwinter cattle, an old system that’s getting new attention.
“Outwintering is reduced input dairy farming,” said Dr. Brad Heins, assistant professor in the Department of Animal Science at the University of Minnesota. “The dairy industry has become far more dependent on outside inputs – everything is coming from outside into the dairy operation. Barns are very expensive to maintain, with ventilation, manure systems and concrete everywhere.” Heins added that the high costs associated with getting into the dairy industry are discouraging to potential new farmers, but outwintering with reduced inputs may be an option for new farmers.
Heins listed a variety of reasons for outwintering cattle, the first of which is lower cost. Cows housed outdoors have fewer health problems, and ventilation is no longer an issue. Bedding costs are lower because less is required, and animals with sufficient bedding are generally clean.
Before making a decision about housing cattle outdoors for the winter, producers should be familiar with several temperature-related concepts related to outwintering. The thermoneutral zone is the temperature range in which cattle don’t have to expend energy to maintain normal body temperature. Cattle going into winter in good body condition with ample feed and shelter can maintain a thermoneutral state in most winter conditions.
The lower critical temperature (LCT) is the temperature at which an animal loses heat faster than it can produce it. Animals exposed to weather conditions below LCT will shiver to maintain body heat. The biggest loss of heat occurs with evaporation of water from a wet hair coat, and loss becomes worse in windy conditions. Animals in extremely cold conditions mobilize body fat to produce more energy, but this loss can be offset by increasing dry matter intake. Animals should be in good condition prior to outwintering, and observed for loss in condition. Producers should also have a backup plan to move cattle to a more sheltered area in the event of a severe storm or extended period of bad weather.
A major consideration for outwintering is secure fencing in good condition in an area that allows easy and frequent observation of cattle for health and well-being. The area should include a windbreak, which can be trees, a man-made structure or a combination of the two. Cattle should have easy access to fresh drinking water and the feeding area.
The outwintering area should be located on a fairly flat and well-drained area, far enough from streams or other bodies of water to ensure springtime runoff doesn’t contaminate waterways. If the land is close to a waterway, consult NRCS for recommendations on creating an ample buffer of undisturbed grassland between the waterway and livestock area.
One potential issue with outwintering is soil compaction resulting from cattle and machinery traffic on damp ground. Regular tractor traffic on partially frozen ground can result in gullies, which collect water and increase the risk of runoff. Plan the travel route carefully to minimize traffic on sensitive ground.
Trips over soggy soil can be minimized by placing large round bales or bagged silage in the field prior to outwintering. Back fence or move cattle to allow access to feed as needed. If round bales are fed in hay rings, move the rings throughout winter to avoid excess trampling in one area. Waste hay distributed throughout the area provides additional organic matter to the soil. If cattle are fed in bunks, watch for buildup of manure around the bunks and have a plan to either move bunks or deal with manure.
Cattle should have access to a clean, dry area for resting time and to conserve body heat. This can be a simple straw pack or a compost barn (bedded pack). A straw pack is out in the open, has good ventilation and involves no building costs. However, feed costs may increase when cattle are on a straw pack because dry matter requirements are higher in cold temperatures and other winter conditions.
One way to establish a straw pack is by loading several large square straw bales in a manure spreader and distributing the material in one place. The area can be rebedded as needed. “Make sure the pack is large enough for cows,” said Heins. “When you get into winter, the pack has manure on it, and that should be kept dry. Cows will lay on it and stay warm.”
Some organic producers house cattle in a compost barn bedded with wood shavings. In many cases, a suitable building for such housing is already present on the farm. It’s important to make sure the barn is well-ventilated and can be easily cleaned.
If a milking herd is housed outdoors through winter, chapped and/or frozen teats can be an issue. To avoid this problem, teats should be dipped and dried prior to leaving the parlor. If allowed by the certifying agency, a dry teat dip powder can be used in extremely cold weather. Heins said the use of dry dips should be limited to about a week and used only in extreme cold because such dips can result in overdrying of teats that become chapped more easily.
As spring approaches, be prepared for mud and flies. Stable flies are significant pests of dairy cows and originate from organic bedding material. “Recent research has shown that straw bedding produces higher numbers of flies than wood chips or sand bedding,” said Heins. “We measured stable fly emergence from the two systems – the number of flies goes up significantly from May to July, then tapers off into September. There are a lot less stable flies out of compost barns than out of straw packs.”
Heins added that weather conditions can influence the number of flies hatching in spring – a straw pack that warms up every morning from the sun will have higher fly emergence. Heins recommended that producers using a straw pack clean it up as soon as possible in spring to avoid generating large fly populations.
“Housing under the stars might not be for everyone, but I think it’s an option to explore,” said Heins. “For beginning farmers, it might be a good opportunity to get into the dairy business without a lot of equity.”