Guest column: Hay, how do I make sure my cows are getting what they need?

Tayler Denman
Ag Extension Educator

With the cooler morning temperatures comes the realization that the seasons are changing. With that realization a lot of livestock producers have begun taking a long hard look at their hay inventory with the hope that it will get them through the winter. Producers should not only be looking at hay quantity, but they should also consider the nutritive value of the hay as well. Testing your hay for forage nutritive value will help you determine the gaps, if any, in nutrition that may require you to supplement to optimize your cattle’s body condition.

First, you must obtain a proper hay sample. A proper hay sample should be taken from each “lot” of hay separately. A “lot” of hay refers to a group of hay that has similar composition, stage of plant maturity, and was cut and baled around the same time. This means that if you have a pasture of bermudagrass and you were only able to cut half of it before your tractor broke down and couldn’t get it finished until two weeks later, those are two “lots” of hay. If you have a beautiful stand of bermudagrass on one side of your field and the other side is well… less than desirable… that would be considered two “lots” of hay. Once you determine your different “lots” you will want to sample about 10-20 bales within each “lot” to get an accurate representation. Each sample should be taken from the round part of the bale using a hay probe. If you are lucky enough to have one that attaches to a drill, I recommend using that. If you don’t, we have one available at our office that you can use (it requires a $40 deposit which will be returned to you once you bring back the probe… in one piece.) This one does not require a drill, it requires good ol’ human strength. Once you take the samples you can bring them to our office and we can send them to the lab for testing. Each sample is $14 and will give you a crude protein and TDN value.

While crude protein (CP) is often what producers look at most as an indicator of good hay, it is an estimation of forage protein by the amount of nitrogen in the hay. If you have hay with high nitrates, it is figured in the CP value even though it is not used as efficiently and can be harmful in high quantities. While protein content is important, sometimes it can be overemphasized and we end up paying for high protein supplementation when it may not be needed. Total Digestible Nutrients (TDN) is a measure of the energy value of the hay. Just about everything a cow does requires energy whether that be walking across the pasture, milk production, and even digestion. If we do not balance energy and protein in your cattle’s diet, you end up with a much less efficient animal.

Once you have tested your hay and taken a good look at the condition of your animals and their nutrient demands you can use all of this information to help decide how much if any, supplementation you will need throughout the winter. Keep in mind that the ideal body condition score (BSC) of cows is 5.5-6 and first calf heifers closer to 6. Whether your cattle are on the low side, right on track, or a little too fat, you can adjust your supplementation accordingly. Supplemental feeding is costly and I don’t know about you, but I would want to meet the needs of my cattle as cheap as possible. By knowing the nutritive value of your hay and condition of your cows, it could help you find the most economical option to get them through the winter.  


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Tayler Denman

Carter County OSU Extension

25 A St. NW

Ardmore, OK 73401


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