How to identify heifers in heat

When using artificial insemination (AI), identifying heifers in heat is essential. Heat detection is a time consuming job on farms, particularly on beef farms where many farmers are part-time.

Most signs of heat occur in early morning and late in the evening and can be missed when farmers are employed off-farm. In order to avail of the best genetics and produce suitable progeny for your target market by selecting a bull to complement a particular heifer/cow and produce suitable progeny for your target market, AI is best practice.

Of course, many farms have a stock bull and the bull will serve the animals as they come in heat. A stock bull may suit certain enterprises, but the initial cost, along with feeding costs, result in an expensive investment compared to the purchase of an AI straw.

Teaser bulls are vasectomised animals that serve as aids in the detection of heifers in heat. We sourced 10 bulls for my heifer puberty project in Trim and got in the local vet to perform the vasectomy. The vas deferens is responsible for the transportation of sperm from the testicles to the urethra, and interrupting this vessel creates a sterile bull that still retains its libido.

A vasectomised bull is preferred to a castrated bull due to the preservation of the sex drive. They retain the urge, but they’re incapable of impregnating the heifers/cows.

I hadn’t witnessed this procedure before so this was a great opportunity for me to get experience in this area. The animals are injected with general anaesthetic before the process. They staggered for a few moments, like they had too many pints, and once rested, the surgery began.

The vet disinfected the area, made and incision and quickly identified the vas deferens, removed a short piece and tied both ends. As I’m sure many can appreciate, it wasn’t until later that day that bulls freshened up, much like the case of a bad hangover.

The teasers won’t be in with the heifers for at least six weeks to ensure no sperm remains in the animal. They will be dressed with a chin ball harness to mark the heifers as the teaser mounts to identify animals in heat and ready for the AI straw.

There are many benefits to using a teaser bull and it was a great experience for me to witness the surgery. But I can wholeheartedly say that I am glad I was the one awake watching the surgery and not the one receiving the aesthetic.