This archive report was first published on 19 June 2020.
Urea, a common ingredient in animal feed, can be deadly to cattle if not used properly. In June 2020, a disturbing incident in Kenya brought this issue to light, with reports of 24 head of pedigree Friesian cattle dying suddenly after being fed an imported feed supplement containing urea.
As a veterinarian, I have seen firsthand the devastating effects of urea poisoning in cattle. The symptoms are unmistakable: salivation, teeth grinding, uncoordinated movement, difficult breathing, protrusion of the eyeballs, collapse, and ultimately, death.
But what exactly is urea, and how does it cause poisoning in cattle? Urea is a natural byproduct of protein digestion in the rumen, the largest of the four stomachs in ruminant animals. When urea is fed as a chemical in excessive quantities or through inappropriate methods, it can quickly kill the animal.
So, how does urea cause poisoning in cattle? The rumen contains billions of microorganisms that convert ingested proteins to urea, which is then broken down to ammonia. The microorganisms use the ammonia to produce amino acids, which are then absorbed into the body to make proteins. However, if the ammonia is produced in quantities higher than the microorganisms can utilize, it is absorbed into the bloodstream and transported to the brain, blocking brain function and causing the symptoms of urea poisoning.
Animal scientists have long known that the ruminant protein production process can be shortened by feeding animals directly with urea, increasing production performance. However, this requires specific adaptation to the change, and introducing new feeds slowly is crucial to give the rumen time to detect the change and increase the population of microorganisms that digest the new feed.
It's essential for cattle farmers to note that adaptation to safely utilize urea is lost in 1-3 days if urea feeding is withdrawn. Animals well adapted to urea feeding can safely consume up to 1g of urea for every kilo of body weight daily, but the same amount can easily kill a cow that is not adapted.
