Match Maker: The Right Hay For Your Livestock
Are you matching the quality of hay to the nutrient needs of your livestock? Here are a few scenarios for ruminants and equines.
By Becky Mills | Photos By Jamie Cole
The needs of a 1,200-pound dry cow (which requires a minimum of approximately 45% total digestible nutrients, or TDN, and 6% crude protein) are several steps down from a 650-pound growing replacement heifer (which needs, at the very least, TDN in the 53% range and 7.5% crude protein).
So, let’s say you have bermudagrass hay cut past its prime, in the 49% TDN and 7.8% crude protein range. That’s fine for the dry cow—even more than she needs—and feeding it to her would allow you to save your better stuff for the heifer, which should do well with ryegrass hay in the 58% TDN and 10% crude protein range. Or, since ryegrass hay more than meets her crude protein requirement, you could feed a lower-quality hay and bump up the energy a bit with a supplement.
It is the same deal for sheep. If you are flushing a ewe (feeding her relatively large amounts of high-quality feed just prior to and early in the breeding season) she needs 59% TDN and 9.1. crude protein. You can meet her crude protein needs with brome hay cut in late bloom at 10%; but the TDN of the brome hay, at 55%, won’t quite do it, and you’ll need to supplement her with a bit of corn to bump up her reproductive rate.
For a 90-pound finishing lamb, you could feed timothy hay cut in the late vegetative stage. This hay might average around 62% TDN and 14% crude protein, which will more than meet his 11.6% protein needs, but almost no hay will meet his requirements of 76% energy. Once again, you’ll need an energy supplement.
If you can figure out how to do a decent job of matching hay to the right class of cattle, you can do it with sheep or goats. Sure, their sizes are dramatically different but the concepts are the same. Not so with equines.
First, their digestive systems are different. With ruminants, the rumen works like a fermentation vat. The on-site microbes do a pretty efficient job of breaking down even coarse fiber into energy. Since horses don’t have a rumen, they rely on a super-sized cecum and large intestine to do their fermenting. The two organs do a darn good job, right up there with ruminants, as long as we’re talking decent hay. However, if it rained for days, you couldn’t get in the hay field or your bermudagrass hay has stems as big around as cigars, don’t count on it doing much energy-wise for a horse.
Second, a horse’s job description factors into his nutritional needs in a big way. Obviously a working ranch horse is going to take more groceries than a pasture ornament.
Third, equine energy needs are usually expressed in digestible energy (DE), measured by megacalories per pound. Oklahoma State University Extension Equine Specialist David Freeman explains, “TDN is a less accurate measure of energy than [DE], because of the variation in the digestive efficiency of fiber.” However, he says DE measurements are not the result of feeding trials but from formulas based on similar feedstuffs. So they can be off by 10 to 20% or more; therefore, other balances relating to energy sources in the diet, such as carbohydrates, fat and fiber, should be considered when selecting feeds.
Freeman says crude protein is usually expressed as a percentage. If you need to convert to pounds, it is simply the amount of nutrient per the amount of total feed weight. For example, 10% protein means onetenth of the feed is protein.
It is critical to know if the values are expressed on a “dry matter” or “as fed” basis. “‘Dry matter’ means the feed weight was reduced by removing the moisture, ‘as fed’ means the feed weight is representative of the weight that is actually fed. Percent of a nutrient on a dry-matter basis would be higher because, although the amount of nutrient is the same, the weight of the total feed is less.”
For more information on nutrient requirements for livestock, check out the following websites:
Nitrate toxicity in livestock
Nutrient requirements of beef cattle
Nutrient requirements of sheep
Composition of livestock feeds, including hay
David Freeman of OSU has a fact sheet on evaluating rations for horses.