SUPPLEMENTING POOR QUALITY HAY Dan B. Faulkner, Extension Specialist, Beef University of Illinois at Urbana-Champaign Many beef cows will be fed poor quality hay this year. The wet spring did not allow producers to harvest hay until it was quite mature and therefore low quality. Hay that was harvested on time may have been rained on which also would reduce hay quality. The only way to determine the exact quality of any hay is to have a forage analysis conducted. A representative sample (usually taken with a bale probe) should be sent to a laboratory. The forage analysis will give a value for a large number of nutrients. The two values of primary concern are energy (total digestible nutrient TDN) and crude protein. Comparing these values to the guidelines given below will allow a producer to determine if the quality is sufficient for a group of cows. Generally, a TDN content of about 52% is adequate for dry cows and 56% is adequate for lactating cows. If the cows are thin or heavy milking the content would need to be 2-4% higher. If the TDN content is not high enough to meet the needs of the cows, supplementation will be needed. How the cattle are supplemented is quite critical. If concentrate (grain and/or protein) supplementation exceed .5% of body weigh (6 lbs for a 1200 lb cow), then cattle will not perform as expected due to negative associative effects. The optimum level of supplementation is .25% (3 lbs for a 1200 lb cow) of body weight. Higher levels of supplementation are possible with highly digestible fiber sources like corn gluten feed distillers dried gains or soybean hulls. Energy supplementation is usually what is needed unless the hay is low in protein (7% crude protein for dry cows and 11% crude protein for lactating cows). If the hay is more than 4% units lower than the TDN requirement, then supplementing cows at .5% of body weight will not meet their needs. Local feed companies also have a variety of supplements available in cubes, blocks and liquid supplements that can be used to meet the cow’s needs. These products should be fed according to company recommendations. When determining how to supplement beef cows a number of factors must be considered. Are there feed bunks to feed corn or other meal type supplements? Is the ground firm enough to feed cubes? If these are not possibilities, then blocks or lick tanks may be the best option. Careful consideration must be given to cost. Supplementation cost must be kept quite low to maintain profitability in the beef enterprise. When evaluating costs it is important to consider both the cost of the corn (or other feedstuff) and the mineral supplement compared to a complete commercial feed supplement (which can contain both). It is important to meet the cows nutrient needs or serious reproductive problems will be observed next summer. Much of the poor quality hay that was harvested each year will not meet the cow’s needs particularly if she is lactating. Therefore, some form of supplementation will be needed to meet the cow’s nutrient needs. Your local feed dealer or Extension Educator can help you if you have questions about sampling, where to send the sample, what the nutrient analysis means, and supplementation alternatives for your hay.