Read your cows' manure

You scrape it, flush it or haul it out of the barn everyday. But what you may not do is use it to evaluate rumen health.

Most people don't take the time to really look at manure. However when you do, you'll find that your cows' manure - particularly abnormalities in its appearance - can alert you to problems with rumen function and your ration, says Mary Beth Hall, dairy nutritionist at the University of Florida.

Hall says five abnormalities, or signs, that are related to rumen acidosis commonly occur in manure. Once you learn to look for the signs - coarse fibers, undigested grain, mucous tubes, bubbly or foamy manure or diarrhea - you can interpret what they mean to rumen health and use the information to help you identify shortcomings in your nutrition program. Then, with the help of your nutritionist or management team, you can use what you've learned to correct any problems.

Manure observations should be part of your normal management routine whenever you walk through a group of cows. The same as you pay attention to how cows walk, body condition and general health of the group, you'll also want to look down at the manure in the pen.

In any group of cows it's normal to see some variation in manure piles, explains Hall. However, if that variation exceeds 5 percent of the group, it may signal a problem. That's when you need to collect a manure sample for evaluation. (See the sidebar "How to prepare a manure sample" on page 64.) The other times you should do a manure evaluation is one to two weeks after a ration change, or whenever the cows tell you something is wrong.

Once you do it a couple of times, remembering to look down to evaluate the manure each time you walk through a group of cows becomes second nature. Use the photographic guide located at right and on the next two pages to help you develop your manure diagnostic skills.

Large fiber particles

Ground grain

What to look for: Large, coarse fiber particles that exceed 0.5 inches in length. The fiber sample shown here came from a loose pile of manure like that shown above.

What it means: Manure that contains coarse fiber particles greater than 0.5 inches in length could mean your cows are not getting enough forage, or physically effective fiber in the diet. When that happens, the rumen can not maintain an adequate fiber mat. Therefore, fiber particles escape the rumen too quickly and do not have sufficient time to be digested or fermented. Feed sorting is a common reason why cows may not be getting enough effective fiber.

What to look for: Noticeable amounts of ground grain or undigested feed in the manure. Grain particles are smaller than 0.25 inches.

What it means: A small amount of grain in manure is not a problem. However, the presence of noticeable amounts of ground grain or undigested feed such as citrus pulp, beet pulp or cottonseed with the lint still intact, indicates the feed has passed through the rumen too quickly. Therefore, it was not sufficiently digested or fermented. Problems with silage harvest methods, slug feeding of grain, and inadequate grinding of dry grain could be the culprit.

Mucin casts

Foamy manure

What to look for: Tubes of mucous or "mucin casts" in the manure. Use the "toe test" to find mucin casts. To do so, slide the toe of your boot across a manure pile. If something that resembles a sausage casing moves after your boot has passed, it's probably a mucin cast. When washed, mucin casts may be long or shredded in appearance (as shown above). They also tend to take on the shape of the large intestine, although they are not part of the lining of the intestine.

What it means: Mucin casts result from damage to the large intestine. This can happen when grain or other fermentable carbohydrates escape rumen fermentation and end up in the large intestine. Once there, these feeds ferment, resulting in acid and gas production. The acid produced as a result of fermentation can damage the large intestine. Mucin casts are the cow's way of saying her large intestine has been injured. The presence of mucin casts often means rumen fermentation is not working optimally.

What to look for: Foamy or bubbly manure. It may have a texture similar to shaving cream.

What it means: Like mucin casts, manure that is foamy or bubbly results from fermentation of grain or other fermentable carbohydrates in the large intestine. However, gas production is the culprit in this case. The gas produced during intestinal fermentation appears as bubbles or foam in the manure. Again, this indicates rumen fermentation is not working as it should, and undigested feed passes through to the large intestine. Foamy manure also could mean grain is passing through the rumen too quickly.


What to look for: Loose diarrhea that exits the cow as a solid stream.

What it means: Diarrhea that results from a non-disease state occurs when feed escapes the rumen and is fermented in the large intestine. This fermentation causes acid and gas production - the two culprits responsible for the production of mucin casts and foamy manure. Acid production irritates the intestine, causing diarrhea. Again, these signs point to inadequate rumen fermentation. The washed diarrhea sample may reveal the presence of coarse fiber particles or undigested feed, similar to what you'd find in foamy manure (shown at left). However, feeding excess protein and some minerals may cause loose manure. Spoiled or moldy feed also may be responsible.

How to prepare a manure sample

Use these steps to collect and prepare a sample of manure for use in a manure evaluation.

Step 1: Collect the sample. When walking through a group of cows, collect four or five samples from individual manure piles. Look for variation when choosing piles so that you get a representative sample. Collect enough manure for an 8-ounce sample.

Step 2: Rinse the sample. Transfer the sample to a 7-inch diameter kitchen strainer or a screen with a mesh size between 0.03 and 0.06 inches. Gently rinse the sample through the screen until the water runs clear.

Step 3: Evaluate the washed sample. Evaluate what remains on the screen. Pay close attention to particle size of any forages, undigested feed, tubes of mucous or other abnormalities left behind. Use the information in the article, "Read your cows' manure," to determine what each means to your cows' rumen health.



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