Judging Hay by Its Physical Characteristics

Equine Department

Judging Hay by its Physical Characteristics

Types of Forage

Forages are broadly classified using three criteria: grasses or legumes, annuals or perennials, and warm-season or cool-season plants. Examples of the most common forages encountered in our region are shown in Table 1. Generally speaking, grasses have fibrous root systems, parallel leaf veins, and bear seed on an elongated seed stalk. Legumes usually have a taproot system, netted leaf veins, and produce seeds in a pod. Legumes tend to be higher in protein, lower in fiber, and higher in calories than grasses. The weather in our region is most conducive to the production of cool-season forages. Cool-season forages grow rapidly in the spring and fall and go dormant in the summer and winter, making them an ever-changing part of the diet. Warm-season grasses grow primarily in the summer in our region, and are lower in protein and sugar (fructan) and less digestible than cool-season grasses.

Common Forages

Since hay makes up the majority of your horse’s diet, changes in factors affecting hay quality will impact your horse’s body weight, growth, and health. Changes in quality factors from one batch of hay to another can easily go unnoticed and cause horses to gain or lose weight.


Assessing hay quality can be done in two ways. Much can be learned from physical inspection, and the more skilled you are at this the more accurate the results. Even more can be learned from utilizing a laboratory analysis. Monitoring your hay with a laboratory analysis as it changes from batch to batch will help you know if adjustments to the grain portion of the diet will be necessary to maintain consistent nutrition to your horse.


Six Physical Characteristics of Hay Quality


1 - Stage of Maturity at Harvest


The stage of maturity at harvest is one of the most important factors in determining hay quality. With increasing maturity, plants become more stalky and indigestible, and nutrient content decreases. As the plant moves from the vegetative stage to the seed set stage, it drops drastically in protein and calorie content (see Figure 1 below). Voluntary intake also decreases with increasing maturity. When hay becomes more mature, the horse gets fewer nutrients from that hay, and he will also eat less of that particular hay. If you are giving your horse access to hay at all times, the actual amount that he will eat is affected by the stage of maturity at harvest.

Growth Stages of Timothy

2 - Hay Texture


Texture is a second factor that can be used to assess hay quality. Softness usually results from cutting at an early stage of maturity, high leaf content, and suitable moisture at baling.


Hay Texture Rating

Very soft – difficult to distinguish between stem and leaves just by feeling

Slightly harsh – stems are a little rough

Harsh – hay is dry, stemmy, and unpleasant to the touch

Extremely harsh – can injure the horse’s mouth, lowering intake


3 - Plant Species


A third characteristic that can be considered is the plant species. If compared at similar stages of maturity, not all plant species provide the same level of nutrients. Legumes provide more nutrients than grasses. Of the grass species, orchardgrass will provide more nutrients than fescue, and fescue will provide more nutrients than timothy when compared at similar stages of maturity.


4 - Color


Color, a fourth characteristic, is affected by bleaching from the sun, rain during cutting, and maturity of the plant. Bright color indicates hay was rapidly cured with no rain damage. However, color can be deceiving. Hay cut at an early maturity that is rain-damaged and off-color may have a higher nutritive value than bright green hay that was late cut.


5 - Odor


A fifth characteristic to consider is odor. A pleasant odor indicates hay was cured properly. Avoid hay with a moldy or musty odor.


6 - Foreign Material

As a final consideration, physical inspection will also detect foreign material or weeds that would be undesirable.


Laboratory Measures of Hay Quality


A laboratory analysis is an important tool to help you determine the nutritional and economic value of your hay. The best feeding programs match the type of hay to the type of horse. For easykeepers and idle horses and ponies, lower grade hay will provide more chewing time and a lower calorie diet while meeting the horse’s roughage requirement. For hard-keepers, broodmares, and active and growing horses, higher grade hay will provide more calories and reduce the amount of grain needed in the diet while meeting the roughage requirement.


A laboratory analysis uses only a few grams of material to represent tons of forage; therefore, sampling technique is very important. CFC Farm & Home Center field personnel can take hay samples upon request when they are in your area.

Hay Market Grades