Results from 500 Hay Samples: What They Do and Do Not Tell Us, and What We Can Do About It

Chris Teutsch UK Grain and Forage Center of Excellence, Princeton, Kentucky

Last fall we analyzed almost 500 hay samples as part of the Eastern Kentucky Hay Contest. A summary of the results can be found in Table 1. So here is what we found:

• Crude protein (3.2 to 21.7%) and total digestible nutrients (41.8 to 68.3%) varied widely

• 6% of the hay samples contained less than 50% TDN

• 4% of the hay samples contained less than 8% crude protein

• Only 57 samples or 11% contained enough energy to meet the requirements of a beef cow at peak lactation

• Only 268 samples or 54% would meet the protein requirements of a beef cow at peak lactation

• 477 samples or 96% contained enough protein to meet the needs of a dry pregnant cow

• 468 samples or 94% contained enough energy to meet the requirements of a dry pregnant cow

So, what does all of this tell us? I guess the biggest take home for me as forage specialist is that I have done a poor job helping people make better quality hay! For you as a cattle producer, the results of these 500 samples tells us that if you are feeding hay to lactating cows, you will likely need to provide some type of supplement to keep cows from loosing condition, especially rst calf heifers that are trying to grow and feed a calf.

So, what don’t these results tell us? Since there was such wide variation in both crude protein and energy for the hay samples in this dataset, no recommendations can be made on what or how much to supplement.

To make this type of recommendation, you will need to sample the hay lots (one cutting from one eld) that you will be feeding (see AGR-257 Hay Sampling Strategies for Getting a Good Sample). Once you have the results in hand, then a supplementation program can be designed by either working your local extension agent or veterinarian or by using the UK Beef Cow Forage Supplementation Tool.

UK Beef Cow Forage Supplementation Tool: An Example

For this example, we will use the “average” crude protein, neutral detergent ber, and total digestible nutrients for the 500 hay samples that were tested as part of the 2022 Eastern Kentucky Hay Contest (Table 1) and assume an as fed dry matter of 12%. When we compare the average values in Table 1 to the nutrient requirements of a lactating brood cow (Table 2), it becomes apparent that this hay will require supplementation. e question then becomes what type of supplement and how much? is can be determined by using the UK Beef Cow Forage Supplement Tool. is application can be used on-line or downloaded to your smart phone. It allows you to enter the results from your forage test (dry matter, neutral detergent ber, crude protein, and total digestible nutrients) and gives you a range of supplement options and how much of each supplement must be fed to meet the cow’s nutritional requirements at a given stage of production (Table 3). e UK Beef Cow Forage Supplement Tool can be found on-line at http://forage-supplementtool.ca.uky.edu/.

When we enter the average values for crude protein, neutral detergent ber, and total digestible nutrients from Table 1, the application indicates that this hay would need to be supplemented with either 4.4 lb corn, 4.4 lb of soybean hulls, 4.4 lb of Corn Gluten Feed, or 4.1 lb of Distillers Dried Grain with Solubles on a daily basis (Table 4). When selecting a supplemental feed, it is important to consider local availability, how and where it will be stored, how it will be fed, how much can be safely fed, and of course how much it costs. It is important to realize that both hay testing and the UK Beef Cow Forage Supplement Tool are NOT perfect. ey are designed to get you in the ballpark and let you