Milk solids of at least +0.03pc and a minimum fertility figure of around €100 are two of the main criteria for bull selection on the Magan farm in Killashee, Co Longford.
Father and son, Mike and Michael, calve down 200 spring-calving cows each year, consisting of mainly pedigree Holstein Friesian cows and a handful of pure Jerseys.
"Our target is 2,200kg milk solids/ha or 550kg solids/cow. Last year we were close to 2,100kg solids/ha so we are moving towards the target," explains Michael.
"One of the bulls that ticks most of the boxes for our herd at the moment is GJM," he says.
"He's got an EBI of €208, €99 for fertility, +20kg for fat and +15kg for protein. He is +0.03pc for protein and he's also got good calving ease figures," he says.
"I've also got about 20 LHZ straws and some SOK straws that I will use on the highest EBI cows," he adds.
A type figure of around +1 is another important criteria for bulls.
The herd's dozen Jersey cows have secured their place in the system through their high milk solids.
"I worked with Jerseys in New Zealand before and I find they work well in our tightly grazed grass-based system. They can be quite profitable little things," maintains Michael.
The Jersey are kept purebred, with Joskin being the bull of choice for them.
Michael keeps a close eye on the cow families behind the bulls he uses.
"It helps if you know the pedigree behind the bull. Sometimes the EBI figures can give a different impression of a bull than what you have seen," he says.
"Sometimes I will choose a bull that may not necessarily be the highest in the EBI rankings but I like what he produces," Michael explains.
The Lynbrook family, including Sultan C, Classic and Splendour, as well as some genomic bulls from the United States are among the bulls he has chosen.
Michael has also been impressed by some of the heifers on the ground from Morning View Legend.