Proper nutrition during the winter months is crucial for all livestock, including beef cattle. It's estimated that winter feed makes up more than half of the annual cost of keeping a beef cow. Maybe you can't tell the difference between 15 and 32 degrees F after spending a few minutes outside, but your cattle can. Slight changes in temperature can have a considerable impact on energy and cow nutritional requirements.
Cold stress occurs when cattle require more energy to sustain basic bodily functions at a specific temperature, called the lower critical temperature (LCT). The LCT helps us understand when cows start experiencing cold stress.
As temperatures decrease, cow nutritional requirements increase. Add in precipitation or wind and requirements increase even more. If cows are shorted on nutrition during cold stress, it can have a domino effect on performance. Nutritional deficiency resulting from cold stress can lead to cows producing lighter and weaker calves. Low-quality colostrum and later return to estrus in the breeding season can also result, compromising conception rates and weaning weights.
Cold stress mitigation should start with keeping cattle warm. Offering protection from the elements like bedding, windbreaks, snow breaks and a place to get out of the mud can all help keep cattle warm and dry. Protecting cattle from wind, rain and snow isn't always enough, however.
Snow often reminds us to think about cow nutritional requirements and supplementation options. But what if the snow never falls? Temperature is the underlying factor in cold stress.
When feeding cattle in winter, provide them with nutrition to meet their needs during cold stress. Plan out feeding strategies early, before cow body condition scores start to slip, to help your cows weather cold temperatures.
Feeding cattle stored forage can be challenging. Testing forages gives you a better understanding of what you're feeding cattle in winter when temperatures drop. Testing total digestible nutrients (TDN) will provide an estimate of the total amount of nutrients that could be digested by the animal. The greater the TDN value, the more energy cattle get from forages.
This is the most important step in understanding if the forage base alone meets nutritional needs or if additional supplementation is required. Conducting a forage analysis provides valuable nutritional information, which can be used to determine the appropriate amounts of supplementation if it is needed. This can also help identify a feasible supplementation strategy for the individual operation. Without a forage analysis, a producer is simply guessing if their strategy meets the needs of their herd.
Daily-fed supplements. Commercial feed blends or byproduct feedstuffs are commonly used as winter feed supplements in beef cow-calf operations. These ingredients generally contain a combination of energy–generally expressed as total digestible nutrients (TDN)–and protein (crude protein, CP), which can be used to supplement low-to-moderate quality forage.
Understanding ingredient composition and quality is important to determine the appropriate feed supplementation level used in daily feed allocation. Producers should review feed tag information to understand the product's quality or ask for a feed analysis to determine feed value. This information, along with forage nutritive value information, can be used to develop an appropriate supplementation strategy for the operation.
Reduced-frequency supplementation. Supplementing with various feedstuffs on a less frequent basis is a common question from a labor standpoint in many beef cow-calf operations. Feeding supplement every other day, or at another defined frequency, is sometimes a strategy used by producers to reduce the time spent supplementing cattle during the winter months. Some feedstuffs are more suited for less frequent feeding than others.
Low-starch feeds may be an option for feeding every other day without altering animal performance when fed with moderate-quality hay. These low-starch feeds contain more digestible fiber, such as soyhulls and corn gluten. When high-starch feeds, such as corn, are fed infrequently, this causes disruption of forage intake and digestibility. Thus, supplements containing mostly starch-based ingredients may not fit this strategy as readily. Producers should follow the label instructions on commercial supplements as a guide for feeding frequency. This is especially important if a product contains an ingredient such as an ionophore or antibiotic in order to maintain product effectiveness and safety.
Limit grazing. Limit grazing is a practice that allows for allocation of animals to high-quality pasture for only a few hours per day. By limiting time on pasture, forage resources are able to be stretched while also supplying high-quality nutrients to the animal's diet. This can potentially improve digestion of the base forage in the diet and improve the overall plane of nutrition for beef cattle.
Creep grazing. Creep grazing allows animals with the greatest nutritional requirement to access high-quality forage while restricting those with lower requirements. This provides a closer match of forage nutritive value to animal needs. In most cow-calf operations using creep grazing, calves are allowed access to high-quality pasture through a creep gate or small access point that excludes cows from entering. When calves are done grazing, they can return to the cow through this opening in the fence. Creep grazing is also a grazing management strategy that is used to more efficiently use limited acreage of high-quality forage.
A cow's energy requirement, or TDN, increases by 1% for every degree below the LCT as a rule of thumb.
However, cow body condition scores impact nutritional requirements. A cow in a BCS 5 needs 30% more energy to maintain body condition than a cow in a BCS 6 at 32 degrees. The same principle holds true as BCS decreases below 5.
A third trimester 1300-pound cow requires 13 pounds of TDN at 32 degrees. However, at 0 degrees the same cow needs an additional 4 pounds, or roughly 17 pounds of TDN. For comparison, the temperature drop means the same cow now requires 8 more pounds of 50% TDN hay.
When feeding cattle in winter, consider a high-quality supplement to help fill a cow's energy gap while helping cows get the most out of existing forages.