Heifers are generally recommended to be joined for six weeks to calve as two-year-olds and cows for up to nine weeks.

Maintaining that target of a tight joining and calving pattern depends on the cows cycling well and the bulls maintaining fertility throughout the joining period.

Bulls ideally should be routinely vaccinated for vibriosis (campylobacter) and leptospirosis. Their pestivirus status should be known.

Pestivirus carriers are not suitable breeding animals as they can introduce the disease to naive herds and cause infertility at joining and abortion outbreaks.

Bulls should be fit and sound to be ready to work.

A bull should be able to handle 50 cows if your management is right and you have fertility information on him.

Scrotal size should be above 32cm.

Testicle size has been shown to have an effect on bull fertility.

The bulls with larger testicles will throw more fertile daughters.

The testicles should be even sized and springy when examined.

Have your vet check any bulls with uneven or soft testicles. The sheath should be free of swellings and discharge or growths.

The bull should be sound in the legs too.

Those back legs are going to be under a lot of pressure for the next few weeks. Feet should be well-formed and not overgrown or cracked. Toes should be an even size.

Hocks should be flat with no swellings.

Swellings around that joint suggest possible early arthritis and a bull more likely to quit or break down.

When you put the bulls out choose bulls of a similar age if you are multiple joining. It is important to make sure the dominant bull is working well as he may prevent other bulls accessing cows even if he is not up to the job.

Any bull that breaks down in the middle of joining disrupts your profit flow.

Breakdowns in joining management may not be picked up until pregnancy testing.

By then it will have cost you 12 months’ production from a cow unless you join twice a year.

Monitor your joining mobs. Watch the bulls for lameness and swellings around the sheath.

Injuries during joining are common. Any infection, such as foot abscess, may make the bull infertile for 12 weeks.

If large numbers of cows continue to cycle after three to six weeks that suggests that there is a fertility problem.