Winter nutritional management strategies
One of the main challenges to beef producers in the western U.S. is to develop a cost-effective winter feeding program while still maintaining acceptable levels of beef cattle production. Many producers in the Pacific Northwest and Intermountain West feed between 2 and 4 tons of hay to their mature cows during the winter feeding period. Feed and supplement costs account for an estimated 50 to 70 percent of total production costs. Therefore, a producer’s ability to compete with other regions depends in large part on his or her ability to reduce these costs. Producers have a variety of management alternatives to consider as they develop economical alternatives to feeding harvested forages.
Costs associated with hay production vary widely according to location, yield and cultural practices, but can exceed $40 per cow for producers in the western states.
Swath, or windrow, grazing is the process of cutting hay and leaving it in windrows for cows to graze in the winter. Allowing cows to harvest cut forage directly can result in lower production and labor costs. Swath grazing has been shown to reduce costs by more than $30/ton over traditional haying systems due to the savings in baling and bale moving costs. Forage quality of swaths is generally similar to that of baled forage. However, a general decline in quality can be expected over the winter months. Energy or protein supplements may be warranted if grazing pregnant or lactating cows, and forage analysis is recommended.
A summary of 10 years of data from the Eastern Oregon Agricultural Research Center demonstrated that cows wintered on swaths had increased body condition and did not require supplements of additional hay compared to cows fed baled forage. Likewise, conception rates, calving interval, weaning weights and attrition rates were equal between control and treatment groups. The practice of swath grazing can generally be used with success in snow depths of up to two feet; however, producers may encounter forage loss and reduced forage accessibility in windy areas or areas with extreme weather conditions such as crusting snow or ice. In order to optimize success with windrow grazing, forage crops should be cut in the fall and windrows should be no more than four feet wide. Cross fencing with electric fence at right angles to the windrows increases forage utilization and minimizes waste.
To estimate swath utilization, assume a cow will consume 2 to 2.5 percent of its body weight. Thus, a 1,200pound cow consumes about 24 dry matter pounds of swath feed per day. If fences are moved to limit cattle to one day’s feed, wastage could be less than 5 percent.
Another alternative to traditional winter feeding is the winter grazing of “stockpiled” forage. To effectively use this alternative, the producer must defer grazing of irrigated pasture and native range to the fall or winter months. The range forage base will be dormant and, as a result, will likely need some level of supplementation depending on quality of selected diets, body condition status of mature cows, and stage of gestation. Quality of standing forage may decline faster than forage stored in bales or windrows. Controlling grazing with an inexpensive electric fence that allows access to a threeor four-day supply of forage at a time can increase forage utilization and reduce waste by up to 40 percent.
Like swath grazing, winter grazing may decrease winter feed costs by $20 to $30 per cow during mild to average years. To effectively utilize winter grazing as part of a management program, the producer should have relatively easy access to grazing animals to accommodate supplementation programs. In addition, it is a good idea to have water available throughout the grazing period, although Canadian researchers have shown that cows can effectively utilize snow as a water source. Indirect benefits of winter grazing relate to the increased management opportunities of traditional hay meadows for spring and early summer grazing. In addition, fall and winter grazing is an alternative use of native rangelands that may provide these significant advantages:
• Grazing dormant forage minimizes damage to native plants from defoliation compared to traditional spring and summer grazing. • Research has shown that non-lactating, gestating cows are better distributed over the grazing area, resulting in more uniform use of the grazed area. Crop residue
Crop aftermath can be utilized in several ways as part of a winter feeding program. Residue may be grazed, baled or chopped. Grazing reduces additional harvesting expenses and also allows animals to select a higher-quality diet. Lack of water supplies and fencing are considerations when grazing crop residue. Corn stalks are a viable winter feed source in corn-producing areas in the Northwest.
A general rule of thumb is that one acre of cornstalks can support a 1,000 pound cow or animal equivalent for 1.5 to two months.
Whole-field grazing is the most common strategy; however, strip grazing may provide a more uniform nutrient intake and also increase utilization. Producers should supply phosphorus and vitamin A to cattle consuming corn stalks. Protein supplements may or may not be necessary depending on the amount of grain remaining in the residue. In some regions, it may be advisable to have an emergency feed source on hand due to the possibility of snow cover limiting grazing.
Straw, a common crop aftermath in the western U.S., can be a good alternative in wintering rations for beef cows if properly supplemented with energy, protein, minerals and vitamins. In general, oat straw has the highest feeding value, followed by barley straw and wheat straw. Beef cows can efficiently utilize rations containing up to 50 percent straw when combined with high quality forage. North Dakota researchers reported similar performance and feed costs between heifers fed alfalfa hay- and cornsilage-based diets compared to diets based on wheat straw and wheat middlings. It is essential to provide a properly balanced ration when feeding straw in order to avoid problems such as stomach impaction, grass tetany, lowered conception rates and malnutrition. In addition to corn and straw, other types of residue that can be utilized include barley field peas, sorghum, soybeans and sunflowers. These vary in nutrient content, and may require additional supplementation. — Janna Kincheloe, Extension Agent, Montana State University, and Ron Hathaway, Extension Agent, Oregon State University