By Lynda M. Vanden Elzen

Is second cut better than first cut?

Is timothy better than orchard grass?

Are alfalfa mixes better than grass hay?

Is soft hay better than coarse hay?

Is low sugar hay better than regular hay?

These are good questions, all with the same answer: It depends on the horse you’re feeding.

Many horse owners want pretty, dark green, soft second cut. When asked about their horse, they describe an overweight, sedentary Quarter Horse. The hay analysis notwithstanding, soft hay is usually lower in fibre, which means the horse can eat more of it more quickly. This is great for a hard-keeping Thoroughbred, but not so great for a fat pony. A hay that is dark green in colour can be high in protein and nutrients, but it can also be high in nitrates, especially when it is local hay grown in British Columbia’s Fraser Valley. High nitrates can cause diarrhea in many horses. Therefore, an appraisal of hay quality is relative to the horse who will be eating it.

Here is a short checklist for evaluating the quality of hay relative to the horse being fed:

Cut, texture and stage of maturity

First cuts tend to grow for a longer period of time, so the plants are more mature with more stalk at the time they are cut and baled. Second cuts contain less mature plants, so tend to be softer. Also, alfalfa tends to come up stronger in second and subsequent cuts, as it prefers dry soils and hot weather.

According to Ashley Griffin, M.Sc., University of Kentucky: “Nutrient value largely depends on the age at which the hay was harvested. Early maturity hay is very leafy and has a high nutrient density and palatability. Late maturity hay contains coarse, thick stems and fewer leaves than early maturity hay. Hay type should be matched to the horse type. Early maturity hay would be perfect for growing horses and lactating mares, but it may not be the best choice for horses with low nutrient requirements. Mid- to late-maturity hays are best for horses with low nutrient requirements because the horses can eat more to satisfy their appetites without overeating and becoming fat.”

Timothy and other grass hays tend to be lower in energy and protein and higher in sugars than alfalfa and other legumes, but the only way to know the nutrient value of hay is to test it.  

Many horse owners believe dark green hay is of higher quality, but the darker green colour can indicate higher protein and nutrient levels, as well as high nitrate levels. Photo courtesy of Wrayton Transport Ltd. Hay Sales, Langley, BC.

How does it test?

Hay testing can provide a great deal information about exactly what your horse is eating. Gone are the days when we had to rely on how hay looked or what was in it – now we can tell, within about a two percent variance, how much protein, fibre, and energy it has, the carbohydrate and moisture levels, and with certain kinds of testing we can know mineral content as well.  Test results are often surprising, and we have learned above all that we cannot assume how any hay will test.

The only way to determine the nutrient value of hay is to test it. Here a bale of hay is being cored to obtain a hay sample, which is put in a Ziploc bag and sent for testing. Photo courtesy of Wrayton Transport Ltd. Hay Sales, Langley, BC.

Grass hays tend to test higher in sugars and lower in protein than legume hays like alfalfa, and alfalfa tends to have a much higher mineral content due to the fact that the roots of the alfalfa plant extend much deeper into the soil than those of grass species. Alfalfa hays also tend to contain more energy per bite than grass hays (visible on the test as Digestible Energy or Relative Feed Value). The amount of fibre – acid detergent fibre (ADF), neutral detergent fibre (NDF), and lignin (indigestible fibre) – is important to consider as well, as it affects the amount of total feed the horse is able to consume in a given period.

A hay sample ready to be sent for testing. Photo courtesy of Wrayton Transport Ltd. Hay Sales, Langley, BC.

Colour

Most horse owners want dark green hay. Many sources state that higher quality hay tends to be dark green. This is true, but it is only part of the truth. A dark green colour can indicate higher protein and nutrient levels, but it can also indicate high nitrate levels. Kansas State University Research Extension provides the following information in its Forage Facts publication:

“The potential for high nitrate concentrations occur when crops such as corn, sorghum, cereal grains, and some grasses are exposed to drought, hail, frost, cloudy weather, or soil fertility imbalance. Nitrates accumulate in the lower portion of the plant when stresses reduce the crop yield to less than that expected based on the supplied nitrogen fertility level. When fed to livestock, nitrates interfere with the ability of the blood to carry oxygen.” As to why nitrates are toxic, the publication explains, “Nitrate toxicity is a misnomer because nitrite (NO2), not nitrate (NO3), is poisonous to animals. After a plant is eaten, rumen bacteria rapidly reduce nitrates in the forage to nitrites. Normally, the nitrites are converted to ammonia and used by rumen microorganisms as a nitrogen source. However, if nitrite intake is faster than its breakdown to ammonia, nitrites will begin to accumulate in the rumen. Nitrite is rapidly absorbed into the blood system where it converts hemoglobin to methemoglobin. Red blood cells containing methemoglobin cannot transport oxygen and the animal dies from asphyxiation.”

This handful of hay appears to be a timothy-orchard grass mix.  Notice the different seed heads, which is a good way to discern the type of hay it is. Photo courtesy of Wrayton Transport Ltd. Hay Sales, Langley, BC.

Nitrates accumulate in a plant when the plant continues to take them up from the soil but is unable to use them. Factors influencing nitrate accumulation include over-fertilization or anything that may stress the plant and stop it from converting the nitrates it has absorbed into amino acids (protein). Some examples of plant stressors are drought, lack of sunlight, inclement weather, and cold temperatures. Plants store their nitrates in their lower portions, so the height of the cutter blade when cutting hay can impact nitrate levels as well.  Higher nitrates can tend to cause diarrhea in horses.

Was the hay treated with a drying agent?

Another factor that can influence hay colour is moisture content at baling. Higher moisture hays will tend to be darker green, where lower moisture hays were usually left out in the sun longer to dry so will be more bleached. This is why hays that were treated with propionic acid, a drying agent, will tend to be darker green and also tend to be less prone to dust or mold – because propionic acid application allows hays to be baled at 18 to 20 percent moisture as opposed to 10 percent or less in non-treated hay. However, propionic acid has its own set of risks and drawbacks.

Equine nutrition specialist Dr. Juliet Getty Ph.D. hypothesizes: “Not considered to be harmful, propionate is one of three volatile fatty acids (VFA) naturally produced by the hindgut bacteria during hay fermentation. The other two VFAs are acetate and butyrate. These VFAs are a significant energy source for your horse. Acetate is utilized by many tissues including the heart, muscles, and the brain. Butyrate provides energy for the cells that line the hindgut epithelium. Propionate is a major precursor toward glucose production through a process known as gluconeogenesis. And that’s a problem for the IR (insulin resistant) horse. Once propionate is absorbed and metabolized, it is converted to glucose, so when you feed alfalfa that has been treated with propionic acid you are essentially increasing your horse’s blood glucose level, just as you would if you had fed a hay with a large amount of sugar and starch. Increased glucose leads to increased insulin. And the rest is… well, you get the picture.”

Some horses fed treated hay have had trouble with hard manure and loss of appetite. This may or may not be due to having consumed treated hay, but is worth noting.

Does the hay contain dust, mold or foreign material?

Consuming excessively dusty and moldy hay can inflame the respiratory tract and cause heaves. Molds in hay can also cause colic and produce mycotoxins. That said, all hay contains some dust and mold. Hay is grown outdoors in fields and there is just no way to ensure that it is completely free of dust or mold. Mold spore levels can be judged as follows, according to Pennsylvania State University:

Prior to feeding, all hay should be inspected for mold, dust, foreign materials such as weeds, and anything that may have been captured inadvertently at baling. Some interesting things show up in hay bales – from sticks and mud to dead animals! That said, most of the time, a horse that’s being fed enough won’t try to eat moldy hay, weeds, or foreign materials.

The definition of “quality hay” is relative to the horse being fed. Some absolutes are true across the board, such as mold and nitrate content, but in terms of protein, texture, fibre, trace mineral content, carbohydrates/sugars, and energy content, no one answer is true across the board because each horse is an individual.

Many of today’s horses are overweight and sedentary, and many of those are metabolically thrifty as it is, thus many of them can benefit from a higher fibre, lower sugar, moderate to lower-protein, lower-digestibility hay. It keeps them eating longer between feedings and reduces the total amount of calories they can consume in a given time period. In contrast, harder keeping, harder working horses like racing Thoroughbreds or eventers require as many calories per bite as we can get into them, so a softer, higher protein, higher energy, lower fibre hay is better for them. Your horse is an individual, so the definition of what is a quality feed for your horse is as unique as he is.

Printed with the kind permission of Wrayton Transport Ltd. Hay Sales. www.wraytontransport.com.

This article was originally published in the November/December 2016 issue of Canadian Horse Journal.

Main Photo: Thinkstock/Photographereddie