| Sensory Evaluation of Hay
Much can be learned from a careful sensory examination of hay. First, the plant species present can be determined.Does thehay consist almost exclusively of a particular forage crop? Does the foragecrop tend to be higher in quality than other forages? Does the hay contain needs? If so, what percentage is weeds and how much nutritional benefit do they provide to livestock?
Could they be toxic?
The maturity of the hay, one of the main factors determining forage quality, can be visually assessed.The number and maturity of seed heads and blooms, and the stiffness and fibrousness of the stems are indicators of plant maturity. Leafiness is particularly important; the higher the leaf content, the higher the forage quality. Leafiness can be affected by plant species, by stage of maturity at harvest, and (especially in legume hays) by handling that results in leaf loss.
Texture is a consideration.
Softness usually results from early cutting, high leaf content, and a suitable moisture level at baling.When hay is “very soft” and pliable, it is difficult to distinguish between stems and leaves just by feeling the hay.“Soft” hay is soft to the touch, but stems can be detected easily.“Slightly harsh”hay has stems that are a little rough.“Harsh or brittle” hay is dry, stemmy, and unpleasant to the touch.“Extremely harsh”hay can injure an animal’s mouth, lowering intake.
Color helps sell hay to the average buyer.
Color alone is not a good indicatorof forage quality, but it can be an indicator of harvest and storage conditions A bright green color suggests that hay was cured quickly and protectedduring storage. Slow curingprolongs plant respiration, which reduces forage quality. Hay that is raindamaged after being partially dried will lose color due to leaching.Mold growth on leaves and stems orexposure to sunlight will also bleach hay. Baling at moisture contents at orabove 20 to 25% may cause high bale temperatures that result in tan to brown or black colors (commonly called “tobacco hay”).
A pleasant odor indicates hay wascured properly.
Moldy,musty odors may occur in hay stored at moisture contents above 16 to 18% (above 14%for 1-ton square bales). Animals may respond to off-odors by going off feed.Odors caused by heating(>125?F) result from hay being baled at too high a moisture content or from ensiling forage that is too dry. Interestingly, hay with a slightly caramelized odor is often quite palatable to livestock, even though the quality is reduced. (The odor of silage can indicate good or bad fermentation; if it smells of butyric acid— similar to rancid butter—it may lack palatability, and low animal intake is likely.)
Dusty hay is usually the result of soilbeing thrown into the hay by rake teeth hitting the soil.
The presence or absence of molds, dust, and odor are referred to as organoleptic qualities.Visual inspection can also detect foreign matter (anything that has little or no feed value).Tools, sticks, rocks, wire, items of clothing, dead animals,and cow chips have all been found in hay and are obviously undesirable. Dead animals in hay can cause botulism, a deadly disease that can kill farm animals.
Alfalfa hay guidelines, used with visual appearance and intent of sale:
RFV calculated using the Wis/Minn formula. TDN calculated using the western formula. Quantitative factors are approximate and many factors can affect feeding value. Values based on 100 percent dry matter.
USDA-WY Dept Ag Market News, Torrington, WY
Dennis Widga, OIC 307/532-4146
24 HR Markets 307/532-7200
Office email: email@example.com
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