July 31 2023 09:34 AM

There may not be a lot of rhyme or reason to why some cows defecate while lying down.

The day of a cattle show can be stressful. Having someone follow the cows around with a manure pan is crucial in order to catch any excrement that comes out the back side. The goal is to keep the cows clean. Yet, there is always that one cow that chooses to defecate laying down. I have always assumed that because they were show cows, they were just being their typical lazy self.

This can also be a problem back on the farm. Cows that leave manure in the stall create a milk quality risk for themselves and the cows that lie there after them.

After reading a research paper published by the Journal of Dairy Science, I realized that there were others noticing this occurrence and wondering why it happens.

In the first experiment conducted, the researchers hypothesized that defecating while laying down would increase based on conditions that would make it more difficult for the cow to stand up. Some of those conditions included older age, heavier body weight, pregnancy, and lameness. Results showed almost half of all cows defecated at least once while recumbent. It was noticed that cows that spent more time lying down and were earlier in gestation were at higher risk. However, age, parity, weight, and lameness were not associated with this behavior.

The second experiment investigated if overstocking influenced the amount of defecating that occurred while recumbent. After studying cows at both 100% and 150% stocking density, researchers found overstocking caused higher stall use and more displacements but less acts of lying down. The less time spent lying down is likely why overstocking did not have an amplified effect on defecating while laying down.

The researchers from the University of British Columbia, Brazil, and the University of Wisconsin-Madison concluded that defecating while recumbent can be common, and they wrote, “We found no evidence that body weight, parity, age, or lameness affected defecation while recumbent.” I was definitely hoping for a more specific reason, with hopes that there was a way we could reduce the occurrence in all our herds to keep cows cleaner and in a more sanitary environment. For now, when a cow chooses to defecate while lying down, it might just be because she is a cow, being a cow. It’s what they do, and as farmers, we will keep cleaning up after them because it’s simply what we do.

Madison Sifford

Madison Sifford is the 2023 Hoard’s Dairyman Editorial Intern. She is a student at Virginia Tech majoring in dairy science and communications. Madison grew up in North Carolina before moving with her parents and sisters to Goldvein, Va. Her family raises Holsteins on their Plessed-Rose Dairy, and they also have a small Hereford cow-calf operation.