Even for the most efficient livestock producers, it is difficult — and some years impossible — to rely solely on pasture to carry livestock through the winter. As pasture supplies dwindle, our primary feed source becomes hay. Winter feed costs can account for the highest segment of annual cost associated with grazing animals.
For example, the winter feed cost for cattle accounts for approximately two-thirds of the total annual cost to keep a cow. Hay quality can greatly affect cattle reproductive performance, body condition, calf health and milk production.
Needs vary
Individual animal needs vary based on their stage of production, body size and environmental conditions. To formulate the best winter feed plan, we need to first consider livestock needs and how to utilize the forage on hand to get through the winter.
The goal of livestock producers should be to match animal requirements to forage quality as best as possible, while monitoring animal body condition through the winter months.
As fall begins, the cows should be in good body condition and score approximately 5. In the fall, we have favorable environmental conditions, and the spring calving cow is in mid-gestation.
If we know our hay quality, we will feed our lower quality hay first, since the cow will have the lowest nutrient requirements at this time. The best way to evaluate forage quality is to have the hay nutritionally analyzed. Your local extension educator can help you find forage testing laboratories.
The onset of winter requires better quality forage for the cow to deal with cold stress. In addition, our best quality forage is needed the last 30 days of pregnancy through breeding season.
The highest nutritional demands are during peak lactation. When comparing energy requirements for beef cattle, requirements nearly double from mid-gestation to peak lactation.
Late-cut mixed grass hay is most often deficient in energy and can be marginal in protein content as well. It may be necessary to consider feed supplements in addition to the hay as cattle proceed into the winter months.
Forage quality changes
It is also important for cattle to receive trace-mineral supplementation year-round. Consider how forage quality changes in the chart below.
The values above are presented on a dry matter basis. The data set source is from Mark Landefeld, retired Ohio State University Extension educator. The date represents the time of first cutting.
Crude Protein is calculated from the nitrogen content of the forage. The CP content is important since protein contributes some energy and provides essential amino acids for rumen microbes as well as the animal.
Acid Detergent Fiber is primarily composed of lignin and cellulose. ADF represents the portion of hay that doesn’t dissolve in an acid detergent solution. It has a strong (negative) relationship with total forage digestibility. As ADF increases, forage quality declines.
Neutral Detergent Fiber consists of the slowly digested fibrous portion of the plant: hemicellulose, cellulose and lignin, which is most of the cell wall. As the total dietary NDF level increases, forage intake tends to decline.
Total Digestible Nutrients is calculated from ADF and estimates the portion of forage that can be digested by cattle. TDN is the sum of digestible CP, digestible fat, digestible non-structural carbohydrates and digestible NDF.
Relative Feed Value combines the nutritional factors of intake and digestibility. It has no units, but the index allows for forage comparisons. Relative feed value is most often utilized in differentiating forage value.
The forage tests above were taken on one farm, same general location in Eastern Ohio, and they illustrate how a cool season mixed grass stand with legume can change in nutritional quality and dry matter yield as that stand becomes reproductively mature. As a livestock producer, harvesting hay on a timely basis greatly affects forage quality. The chart above illustrates that even within the same field and same basic forage content, the ability of this forage to meet the nutritional requirements of beef cattle changes dramatically from May to June.
For example, a 1250-pound beef cow near calving fed hay number 6 would be expected to lose almost 1 BCS in as little as 51 days. That same cow-fed hay source number 3 would take 2 times longer to lose one BCS.
Forage quality affects farm profitability, animal productivity and animal health. If you have made your first cutting in June, you may need to provide additional feed supplementation.
Evaluate your forage quality to know where your animal production is headed.
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