Cows feeding on silage

Ensiled forages are the most common feeds used on the dairy farm. Silage are used primarily due to their potentially lower harvest and storage nutrient losses. Silage also allow for greater flexibility in moisture content of feed at harvest. One can gain significant insight as to the quality of silage, or hay-crop, by its smell, sight, and feel. Sensory evaluation may suggest the need for further chemical or physical characterization of the feed should a problem be identified. Your silage maybe sensory evaluation of silage would include the following

Observe the contour of the bunker face

Ideally the face should be very smooth and straight. This minimizes oxygen exposure to the silage. Bunker silos with irregular and uneven faces have greater surface area exposed to oxygen and thus a greater chance at increased microbial activity. As silage is reintroduced to air, mold and bacterial spores present in the silage can begin their metabolism again. This metabolic activity will result in silage heating as well as alterations in acids and sugars available in the feed. This metabolic activity suggests unstable silage and can contribute to depressed feed intake and feed refusals. This secondary heating is usually not sufficient to cause significant heat damage to the silage. The true value of bunk face management is not well known and is related to the density of the silage, the season of the year, and the amount of silage face that is removed each day.

Silage color

can indicate potential fermentation problems . Silages with excessive acetic acid will have a yellowish hue, while those with high butyrate will have a slimy, greenish color. Brown to black silage usually indicates heating from fermentation and moisture damage. These silages have the highest potential for molding and are unacceptable feeds. White coloration of silage is usually indicative of secondary mold growth.

Silage odors

This method can also be used to evaluate fermentation. Normal silage has minimal odor due to lactic acid. If acetic acid production is high, then silage may have a vinegar smell. High ethanol content from yeast fermentation may impart an alcohol odor to silage. Clostridial fermentation results in a rancid butter smell. Propionic acid fermentation results in a sharp, sweet smell and taste. Heat-damaged silages will have a caramelized or tobacco smell. No silage should have a musty, mildew or rotten smell due to molding. Remember if the silage smell is really unpleasant to you, most likely it will be refused by the cow or cause reduced intake.

Next time you want to evaluate your silage, just go with these methods as your helping hand.

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