“Deworming Feeder Cattle”
by Chris Reinhardt, feedlot specialist
The value of deworming pasture and feedlot cattle has been clearly demonstrated to the livestock community; the research is definitive and media surveys indicate that ranchers and cattle feeders have gotten the message loud and clear.
But if you dig very deep into the science of deworming, into specific parasites, life cycles, and mode of action of different dewormers it is very easy to become overwhelmed with the seeming complexity of the situation and potential solutions. The good news is you don’t have to dig very deep to understand the issue.
Parasites live most of their life inside the animal, but require green grass, moisture, and relatively warm temperatures to start the life cycle over. Eggs are laid by mature females living inside the animal and excreted in feces; warm temperatures stimulate the eggs to hatch and release larvae; larvae reside in dew drops on blades of grass and are consumed by the animal; the larvae then mature inside the host. In short, if there are eggs in the feces, the cattle have mature worms inside their digestive tract.
If you receive cattle which have been grazing green grass, they are likely carrying some level of internal parasites. If you receive cattle which have been in drylot and were effectively dewormed upon arrival in that drylot they should have little to no parasite burden leaving the drylot; there’s no chance for them to have become re-infected. There is a simple test that your veterinarian can conduct, using a small amount of fresh manure, to determine the level of internal parasites and the effectiveness of your deworming program.
Parasites make it difficult for cattle to respond to vaccination and to fight off viral infection because the 2 different types of immune battles are competing for immune resources. If you are having unexpected health problems several weeks or months into the feeding program, you may wish to have the cattle examined for internal parasites.