Editor's note: Ray Hinders, dairy nutritionist and owner of Hinders Nutrition Consulting in Acampo, Calif., handled the following case study.

Thank goodness the farm owner was observant.

When he first noticed that his cows had loose manure, he called his nutritionist. Could it be a lack of fiber in the diet? Had silage moisture changed? Or, was it something more insidious?

Certainly, a change in silage-moisture level could change the amount of forage dry matter being fed. If the moisture level increased, and the feeders did not adjust for those changes, less forage and less forage fiber would be fed — and that could result in loose stools if fiber in the ration was lower than desired. A change in moisture content might also signal a change in silage quality.

The 850-cow farm was well-managed, and the feeder did a good job of mixing the rations. So, perhaps there was some kind of change in feed quality.

When he arrived at the farm, nutritionist Ray Hinders wanted to take a look at the corn silage. And, it didn't take long to notice a light gray mold growing along the face of the bunker silo, which was surprising for this farm. "Normally, we just don't see any mold on his corn silage at all," Hinders says.

It turns out that someone peeled back the plastic covering on the bunker silo a little further than normal. The feeder, who was normally very conscientious, did not know how to deal with that, so he dug into the bunker silo a little deeper than usual with his front-end loader. By digging 3 feet into the bunker rather than 1 foot, the feeder wasn't getting across the entire width of the bunker silo as quickly as he should have. In fact, it was taking him a full five days to get across the entire width.

With some of the silage left untouched for four to five days, there was enough moisture in the silage for mold to form. The feeder simply didn't realize this could occur.

Things were starting to add up. Not only were the cows showing loose manure, but their milk production and feed intake were suffering as well. Milk production, which had been averaging 80 pounds prior to this latest bout, made a precipitous drop to 74 pounds. And feed intake fell from 59 to 60 pounds per day to 56 pounds.

Although he was pretty sure that mold was the problem, Hinders went ahead and had the silage checked at a reference lab. The results for fiber, moisture and non-fiber carbohydrate were similar to a previous analysis — prior to the mold problem.

The mold on the face of the bunker was only about 2 inches deep, so the feeder simply peeled off the outside edge with his front-end loader and discarded the feed. Meanwhile, the farm cut back the amount of corn silage it was feeding to cows for a few days and substituted in some oat hay. And, the farm also used a feed additive to help diminish the effects of mold. Within two days, milk production rose from 74 pounds to 77 pounds, and within eight to nine days it was back to 80 pounds.

Thanks to an observant owner, Hinders was able to get on top of the problem quickly. The dairy continues to watch manure consistency for any sign of problems.