What is the Nutrient Value of Your Hay?

Mark Landefeld, OSU Agricultural Extension Educator (this article first appeared in the Late Fall 2015 issue of the Ohio Cattleman Magazine)

Each year as May and June arrives; most cow/calf owners’ make hay in preparation for their livestock’s winter forage needs. The 2015 season was no exception. Producers watched weather forecasts looking for those three day windows of opportunity to get their hay cut, dry and baled. As usual, there were a few chances near the end of May and maybe one or two windows in early June to make hay, but then precipitation seemed to occur almost daily. The wettest June on record was recorded in 2015, according to some local weather stations, and the rainy weather pattern continued for more than a month. This caused the majority of Ohio farmers’ first cutting hay to be made in late July and August.

Many years of data and forage tests are available that show how the quality of a forage, such as hay, decline as the plants become more mature. A series of forage tests from two eastern Ohio studies, conducted several years’ apart and in different locations, indicate nearly identical results. Forage quality in early May was very high with crude protein (CP) levels reaching >24%, but tonnage/quantity was very low (<1 ton/A). The samples taken the last of May and first week of June showed the tonnage/quantity had increased significantly (>2.5 ton/A), but forage quality decreased and CP levels were then down to 12.6%. Even though the level of nutrients in those late May and early June sampled forages were decreasing they were still sufficient for beef cows in the last 1/3 of pregnancy and the early lactation stage. However, by June 15th in both studies, quality values really plummeted. Tests revealed that CP levels went down to 7.6% or less and that would have made the hay deficient in nutrients for late pregnancy or lactating cows. Tonnage/quantity sampling at that time indicated there was still a slight increase being accumulated, but it leveled off quickly.

Ok . . . back to 2015. So what is the quality of your hay? The best way to find out is to take forage samples from your bales and have laboratory analysis done. Sampling multiple lots of hay would provide the best picture of your overall situation and provide information for you to make the best use of the forages. Different production dates, the variation of grass vs. amount of legume composition in fields or different rates of fertilizer applied could all be reasons for sampling multiple lots of hay. One thing to remember, forage analysis results are only as good as the samples taken. A good fact sheet describing sampling technique may be found at http://ohioline.osu.edu/anr-fact/0002.html or a YouTube video on the subject is embedded below:

Laboratory analysis of hay samples I have seen this year are all over the board in terms of quality. As one might expect, with much of the hay being made long after reaching maturity, some samples revealed the forage quality was really low, but surprisingly, some first cutting hay that was made in August showed higher than expected protein percentages and energy levels. This may be due to the fertility differences and/or extra regrowth that developed, as a result of extremely wet conditions, before first cutting could be harvested.

Laboratory test results can help producers determine which hay should be fed to the cows first or what should be set aside and saved for later. Different stages in a cow’s yearly production cycle require different amounts of nutrients. The National Research Council (NRC) has tested beef cattle production as well as variations in nutrient utilization and requirements. NRC has developed many livestock nutrition charts and tables listing the nutritional needs of various livestock. Use your favorite internet search engine and type in “NRC Beef Nutrition”. The seventh revised edition of Nutrient Requirements for Beef Cattle should be listed along with many other documents and the NRC book may be downloaded for your use.

Crude protein and total digestible nutrients (TDN) are two of the most commonly used figures with beef cattle nutrition. Comparing figures from your tests to those published by the NRC for livestock of your size/weight, class and stage of production allows you to determine if your hay will meet their nutritional needs without using expensive concentrate supplementation. For example, the NRC charts show after weaning, a dry pregnant cow’s nutritional requirement is at the lowest stage for her entire yearly cycle. She does not need the best quality feed you have on the farm at this time. Matching forge quality with nutritional need makes the best use of available forage. March/April calving cows can get by consuming lower quality forage until about mid-January when nutrition requirements start to rise. This would be the time to use concentrate supplementation, if needed, or use higher quality hay that was identified through your forage testing.

Providing more nutrition than a cow needs can become expensive, but under feeding nutrients can be a disaster. Just because there is hay in the rack for the cows to eat does not mean there are enough nutrients in the hay for her to function properly. Extended periods of poor nutrition can lead to calving problems, weak newborns, poor quality milk, rebreeding problems and many other costly complications. Low quality hay simply cannot provide enough nutrients in relationship to the amount a cow can eat and forage testing can alert the producer to this potential problem. Stop by your local Extension office now and borrow a forage probe to pull those samples.

Using information provided by a forage analysis a producer can better prepare for the winter feeding period ahead. Also, using the Body Condition Score (BCS) system will help verify if nutrients being fed are calculated properly and distribution among all animals is adequate. A body condition scoring chart, Extension publication L-292, shows pictures and lists body condition descriptions. It may be found at http://ohioline.osu.edu/l292/index.html