Source: University of Wisconsin-Madison Division of Extension
Author: Beth McIlquham
Introduction
Every spring and summer bring new challenges to growing crops in Wisconsin. This year is no different. To optimize cow productivity, evaluating nutrient levels in winter feed for cows is necessary. All nutrients are vital in raising healthy cattle, but protein is commonly overlooked during winter. Since the growing season was challenging, supplementing protein could help maintain the performance of your herd through the cooler months. Protein supplementation can be a costly part of a nutrition plan, however, keeping feed quality high for your cows can pay off in the future.
Why supplement protein to cows?
Inadequate protein levels deprive rumen microbes of the nitrogen needed to digest forage efficiently. Feeding the microbes in the rumen is important for overall cow health. When nutrient needs are met, cows can gain and maintain body condition more easily. Correctly fed cows can produce offspring that have increased value at weaning and beyond. Steer offspring have been shown to fetch a higher value at slaughter because they earn a higher quality grade without affecting yield grade. This can be especially valuable if feeding out your own cattle but can also help increase the reputation of your cattle if they are sold to be finished elsewhere. Heifer offspring tend to have a higher pregnancy rate and tend to hit puberty earlier. To reap benefits of high-performing calves, adequate nutrition must be provided to the cow during gestation. Since 75% of fetal growth happens in the last third of pregnancy, inadequate nutrient levels during the third trimester could damage the future performance of calves.
When should protein be supplemented?
Before buying costly protein supplements, you need to know how much protein you are already feeding. Get your winter feed tested to ensure you provide adequate protein to their diets. If you identify a deficiency, it is time to investigate some options.
For the rumen microbes to do their job well, adequate protein must be fed. Actual protein needs vary based on animal size, gestation period, and lactation stage. For example, a 1,200 lb. dry cow in the last third of her pregnancy will consume 22.3 lbs. of feed on a DM (Dry Matter) basis per day, assuming a common beef cow type hay is used at 53% TDN (Total Digestible Nutrients). In this example, she will need 1.7 lbs. of protein a day. Knowing the pounds of protein needed and the pounds provided by the hay will allow you to determine how much may need to be supplemented. To identify the specific needs of your herd, check out this free resource from Oregon State University Extension Service using Table 1.2 on pages 15-16.
What is the best protein supplement?
That depends! Protein comes in many forms such as blocks, liquids, high-quality forages, and commodity co-products. Supplementing a nonprotein nitrogen, such as urea, could be an option but be sure to avoid ammonia toxicity. Urea should never exceed ⅓ of the animal’s total protein requirements. Other protein options include soybean meal, alfalfa, distillers grains, corn gluten meal, and many more. Be sure to shop around to see what best fits your needs.
Is there more to know before buying?
Before buying, analyze the cost per pound of utilizable protein, not just the cost per ton of the supplement. Remember, you are buying the nutrient, so a cost evaluation should be done on the nutrient itself. Utilize this free feed cost tool provided by UW-Madison Division of Extension for guidance.
Conclusion
Supplementing protein may be necessary for this winter. Evaluate what your cows are eating for protein and other nutrients as well. A proper diet can help rumen microbes function properly, allowing cows to produce high-performing calves.
References
Beef Cattle Nutrition Workbook. Oregon State University Extension Service. 2004.
https://extension.oregonstate.edu/sites/default/files/documents/em8883.pdf
D. M. Larson, J. L. Martin, D. C. Adams, R. N. Funston, Winter grazing system and supplementation during late gestation influence performance of beef cows and steer progeny, Journal of Animal Science, Volume 87, Issue 3, March 2009, Pages 1147–1155,
https://doi.org/10.2527/jas.2008-1323
R. C. Cochran, et al., Cubed Alfalfa Hay or Cottonseed Meal-Barley as Supplements for Beef Cows Grazing Fall-Winter Range. Journal of Range Management, vol. 39, no. 4, 1986, pp. 361–64. JSTOR,
https://doi.org/10.2307/3899780
R. N. Funston, J. L. Martin, D. C. Adams, D. M. Larson, Winter grazing system and supplementation of beef cows during late gestation influence heifer progeny, Journal of Animal Science, Volume 88, Issue 12, December 2010, Pages 4094–4101,
https://doi.org/10.2527/jas.2010-3039
