Q: What are the three Cs of manure evaluation?

A: Recently, I’ve been doing a lot of manure sampling, which translates into me turning around and running to every cow I hear starting to defecate. It also means that I’ve been spending a lot of time looking at manure, and realizing how different it can be.

Manure differences aren't just from one cow to the next. There can be day-to-day or even same-day changes from one cow. Manure can tell you a lot, whether it’s about the ration, cow health or even the cow’s eating habits – you just have to take the time to look.

There are a number of factors to take into account when visually analyzing manure:

Color. The color of manure can vary based on the type of diet the cow is consuming. There isn’t one “normal” color for every farm, but the color should be fairly consistent within a herd. Cows on pasture, for instance, would have more dark green-brown colored manure than those fed TMR or a hay-based ration, which you would expect to be more in the lighter brown-yellow range. It’s important to look at the cows on a farm and distinguish what “normal” should be, so you ca detect when things aren’t quite right.

Manure that’s much darker or bloody in color can be indicative of hemorrhaging in the GI tract, whereas manure that is light green/yellow can be indicative of a bacterial infection. Knowing the normal color of manure on your farm can help to distinguish cows that might have a problem.

Consistency. The consistency of manure should be similar in cows that are in the same pens and fed the same ration. Only about 5% of cows in a pen should have manure that looks very different from her pen mates. Finding more than 5% of cows with different manure then penmates might indicate sorting or slug feeding. There is a general scoring for manure, the system ranges from 1 to 5 and is listed below:
1 ─ Very runny manure, may form an “arc” when coming out of a cow, diarrhea-like.
2 ─ Runny manure, does not form a distinct pile, splatters when hits the ground.
3 ─ Porridge-like manure, stacks 1.5-2” off the ground in a pile, and sticks to the toe of your shoe.
4 ─ Thicker manure, stacks higher than 2” in a pile and will stick to the toe of your shoe.
5 ─ Appears as firm fecal balls.

Optimal scores for lactating dairy cows would be in the 2.5-3.5 range. Generally, fresh cows will have scores around 2.5, and late lactation cows will be around 3.5. Scores of a 1 or 5 would indicate that those cows may have health issues. If most cows have scores less than 2 or more than 4, then the ration may need to be evaluated and reformulated.

Content. Manure content can tell you how well cows are utilizing their feed and if they are undergoing any health issues. The first thing to look for would be any undigested feed particles. Lots of longer particle size pieces of corn silage or green grass indicate the rumen is not functioning properly and not digesting feed completely.

If there are undigested grains or smaller particles, it can mean an increased rate of passage due to slug feeding or other causes. Any undigested feed in manure is not being used by the cow for milk or maintenance needs, and is decreasing feed efficiency. Ensuring that cows are receiving the proper rations to promote optimum feed efficiency can save money on feed costs.

Manure should also not be foamy or contain mucous components. Foamy manure can result from gas production due to excess hindgut fermentation, which is not desirable. Mucous-like components, called mucin casts, in the manure are indicative of hindgut damage and are shed out of the large intestine. If too much acid is produced in the hindgut the intestinal wall can be damaged. When the wall is damaged mucin is produced and used by the body to help protect the lining of the intestine, the mucin is then shed later the manure. Regardless of the cause, mucin casts are signs of damage to the gut and should be considered abnormal.

Evaluating manure is a very useful and inexpensive tool to ensure you have healthy, efficient cows. Keeping an eye on manure color, consistency and content can tell you a lot about your cows. So next time you’re walking through a pen don’t just dodge the manure, take a few seconds to look and evaluate it on your own and get a better idea of what is really going on with your cows and your ration.