Manure evaluation

Manure indicates the condition of the rumen and intestine of the cow. Manure from a healthy, high-producing cow should look like a pile of shaving cream. Too much DIP will increase manure looseness. Within a group of cows experiencing acidosis, some manure will be stiff, some just right, and some will be loose, pasty, somewhat shiny, and contain small bubbles. Grain will be seen in the manure if there is poor rumen mat formation due to a lack of effective fiber or if the rumen microbes are not able to digest the grain fast enough. Mature, unprocessed grain will be digested slowly.

Manure evaluation can provide a huge clue when trying to evaluate conditions inside the rumen and intestine of the dairy cow. Many producers are aware that loose manure can be a sign of too much dietary protein but they don’t realize that manure can change based on rumen health. Even in situations where the cows are milking reasonably well, the manure may not look exactly like it should. Making ration improvements to make the manure look better will increase milk production further and, more importantly, improve feeding efficiency.

What Does Ideal Manure Look Like?

Manure from a high-producing cow should look like a pile of shaving cream. Some call it porridge consistency. It should have 3-6 rings and stand up about 1.5 inches (3.8 cm). It should have a dimple in the middle. You should be able to see very little grain or fiber particles (greater than ¼ inch (0.64 cm) in length) in the manure.

Rumen Degradable Protein (DIP) Affects Manure

Often, when producers change to better hay crop silage that is higher in protein and they don’t rebalance the ration, the manure will get looser because of too much DIP in the diet. Usually, when this happens, all cows in all groups have loose manure.

Acidosis Affects Manure

Manure that is loose, pasty, somewhat shiny, and contains small bubbles is a pretty sure sign of acidosis. When acidosis is occurring in a group of cows, some cows will have rather stiff manure, others will have perfect manure, and others will have the typical acidosis manure as described. This inconsistency is a key difference between manure that is loose because of too much degradable protein and manure that is loose because of acidosis. The reason for this inconsistency is acidosis is making cows go on and off feed.

For example, on Monday a cow may feel fine, eat well, and have good manure. On Thursday, she may be experiencing acidosis and will have loose, pasty manure. Then, she eats less over the next few days and eats more fiber. On Saturday, she has stiff manure. This inconsistent manure can also be a sign that cows are sorting through their TMR and eating more fiber at one time and more concentrate at another time. Sorting results in acidosis.

Fiber in the manure can also be a sign of acidosis. When the amount of long, effective fiber consumed is less than adequate, the rumen mat will not form properly. The rumen mat is essential for keeping fiber in the rumen long enough to be fermented. Without a good rumen mat, more fiber passes out of the rumen and ends up in the manure. The fiber-digesting microbes are also slowed by acidosis, causing more fiber to appear in the manure.

Why Does Acidosis Manure Contain Bubbles?

When acidosis occurs, fiber digestion in the rumen is reduced because the fiber-digesting bacteria have difficulty functioning in acid conditions. Acidosis is often caused by less than adequate, effective fiber intake. When this occurs, a good rumen mat isn’t formed. The rumen mat is essential for keeping fiber and grain in the rumen long enough to be digested. So, more fiber and grain pass into the large intestine and are fermented there. Gases are produced when microbes ferment feed. The microbes are still fermenting and producing gas as the manure is passed out of the cow. This is a wasteful situation and shows up as tiny bubbles in the manure.

Why Does Acidosis Manure Look Shiny?

If enough acid passes down to the large intestine or is produced there, it damages the intestinal lining. The cow produces mucus to try to take care of the damage caused by the acid. This mucus appears shiny when it passes out in the manure.

What Causes Manure To Become Loose?

When acidosis occurs, some lactic acid passes out of the rumen and down into the large intestine. Also, more grain passes down into the large intestine and ferments, producing acids. The cow’s response to the extra acid in the large intestine is to bring in water from the bloodstream to try to equalize the ionic pressure caused by lactic acid. This increases the fluidity of the manure and makes it appear loose. When too much protein or mineral is in the diet and it passes into the large intestine, water is also drawn in from the bloodstream in an attempt to balance the concentration of solutes and manure gets loose.

Why Does Grain Show Up in the Manure?

Grain will be present in the manure if it passes out of the rumen too rapidly. Two factors cause this. First, poor rumen mat formation will increase the speed with which grain passes out of the rumen. This can be remedied by increasing ration fiber levels and/or increasing the length of cut of the fiber in the ration. Second, if the rumen microbes are digesting grain too slowly, it will show up in the manure. A lack of rumen degradable protein and/or specifically soluble protein may slow down the rumen microbes and result in grain in the manure. Also, some starches are naturally slowly digestible and need to be processed by grinding or cooking in order for the rumen microbes to digest them faster. Too much slowly digestible starch in the ration will result in grain in the manure. The rumen microbes require a blend of fast fermenting starches and sugars and slowly digesting starches. Often, the amount of grain in the manure can be reduced by replacing some slowly fermentable starch with rapidly fermentable starch and sugar. With typical diets in temperate climates, 2-4% supplemental sugars and 3-6% fast degradable starches, such as bakery product or flour, often helps.

Remember that as more grain is fermented in the rumen and less grain passes out in the manure, acid production in the rumen increases. Adequate effective fiber is necessary. The amount of grain fed may also need to be reduced to avoid acidosis. More grain digestion in the rumen should increase the amount of energy and protein available for milk production. Higher milk production, at the same time as grain feeding is reduced, increases feed efficiency and profitability.

Manure Scoring Guide

ScoreAppearanceNutrition Factors

Liquid (like pea soup)
Puddles and Runs

Too much protein or too much starch
Not enough fiber Excessive mineral consumption

2 Runny
Piles less than 1”(2.54 cm) deep Appearance of rings
Similar to #1
Cows grazing lush pasture
3 Shaving Cream Consistency
Piles up to 1.5” (3.8 cm) deep 3-6 Concentric Rings Dimple in the middle
Balanced Ration
4 Thick
Piles more than 1.5” (3.8 cm) deep
No dimples
Too little protein or too little starch
Too much ration fiber
Dry cows or Heifers
5 Firm
Piles more than 2-4” (5-10 cm) deep
High forage diet Dehydration







Adapted from Andy Skidmore, Michigan State University as cited by M. Hutjens, 1996


Allen, M. and D. Beede. 1996. Causes, detection and prevention of ruminal acidosis in dairy cattle examined. Feedstuffs, September 9, 1996, p. 13.

Hutjens, M. 1996. Manurology 101. Dairy Today, February 1996, p. 26.


Mary Beth de Ondarza

Mary Beth de Ondarza
45 articles

Nutritional consultant for the dairy feed industry at Paradox Nutrition, LLC.

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Dr. de Ondarza received her Ph. D. from Michigan State University and her Masters Degree from Cornell University, both in the field of Dairy Nutrition.

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Paradox Nutrition

Paradox Nutrition

Paradox Nutrition, LLC is a nutritional consultation business for the dairy feed industry. Mary Beth de Ondarza, Ph.D. is the sole proprietor.

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