What Manure Can Tell About a Feeding Program

What comes out the back end of a cow can tell us a great deal about what is going into the front end! Dr. Michael Hutjens from the University of Illinois discussed the evaluation of manure as a management tool in his paper “A Blueprint for Evaluating Feeding Programs”, which he presented at the 2002 Western Canadian Dairy Seminar. An excerpt of Dr. Hutjen’s paper is reprinted with the kind permission of the Western Canadian Dairy Seminar. Be sure to take in the 2003 WCDS in Red Deer on March 10-13.

Scoring Manure

Michigan workers developed a scoring system to evaluate fresh manure. Consistency is dependent on water and fiber content of the manure, type of feed, and passage rate. A scale of 1 to 5 is listed below with a score 3 optimal.

• Score 1. This manure is very liquid with the consistency of pea soup. The manure may actually “arc” from the cow. Excess protein or starch, too much mineral, or lack of fiber can lead to this score. Excess urea in the hindgut can create an osmotic gradient drawing water in the manure. Cows with diarrhea will be in this category.
• Score 2. This manure appears runny and does not form a distinct pile. It will measure less than one inch in height and splatters when it hits the ground or concrete. Cows on lush pasture will commonly have this manure score. Low fiber or a lack of functional fiber can also lead to this manure score.
• Score 3. This is the optimal score! The manure has a porridge-like appearance, will stack up 1 ½ to 2 inches, has several concentric rings, a small depression or dimple in the middle, makes a plopping sound when it hits concrete floors, and it will stick to the toe of your shoe.
• Score 4. The manure is thicker and stacks up over 2 inches. Dry cows and older heifers may have this type of manure (this may reflect that low quality forages are fed and/or a shortage of protein). Adding more grain or protein can lower this manure score.
• Score 5. This manure appears as firm fecal balls. Feeding a straw-based diet or dehydration would contribute to this score. Cows with a digestive blockage may exhibit this score.

Manure scores 1 and 5 are not desirable and may reflect a health problem besides dietary limitations. Score 2 and 4 manure may reflect a need to rebalance the ration. As cows progress through their lactation, manure score may also shift as outlined below.

• Fresh cows (score 2 to 2 ½)
• Early lactation cows (2 ½ to 3)
• Late lactation cows (3 to 3 ½)
• Far off dry cows (3 to 4)
• Close up dry cows (2 ½ to 3 ½)

Increasing the amount of degradable, soluble, or total protein, decreasing the amount or physical form of the fiber, increasing starch level, decreasing grain particle size (such as fine grinding or stem flaking), and consuming excess minerals (especially potassium and sodium) can cause manure scores to decline.

Manure Colour

The color of manure is influenced by feed, amount of bile, and passage rate. Manure from cows on pasture is dark green while hay-based rations are brown. Manure from high grain-based diets are more gray-like. Slower rates of passage cause the color to darken and become more ball-shaped with a shine on the surface due to mucus coating. Score 1 may be more pale due to more water and less bile content. Hemorrhage in the small intestine causes black and tar-like manure while bleeding in the rectum results in red to brown discoloration or streaks of red.

Washing Manure

Washing manure through a screen (6 to 8 squares to the inch) allows the dairy manager to quickly find or “see” if feed processing and digestion is optimal. Take a cup of fresh manure and wash it with a stream of warm water through the screen removing the digested material. It typically takes about 30 seconds if your screen has sides allowing for more water pressure. Look for the following remaining feed particles.

• Finding pieces of barley or corn grain with white starch remaining indicates that some feed value was lost. If the seed and starch pieces are hard, additional grinding or processing may be needed to expose the starch to rumen microbial fermentation or lower gut enzymatic digestion.
• Corn kernels from corn silage reflect that the seed was too hard for digestion and chewing by the cow. Mature and dry corn silage can cause this observation as grain is hard. If roasted soybean seeds are hard, they must be processed finer. Wisconsin workers suggest breaking soybeans into fourths or eighths.
• Forage particles over ½ inch long may reflect a lack of long forage particles to maintain the rumen mat and adequate cud chewing.