Liquid milk supplier Michael McDonnell from Cannontown Farm, close to Termonfeckin in Co Louth, calves down close to 500 cows each year.
His herd of pedigree Holstein Friesians calve all year round, although the peak calving times are usually July and January to February.
"We are calving for about 10 months of the year," he says.
The Glanbia supplier rears all his heifer calves and sells the majority of the bulls calves at two weeks of age. The bulls are usually bought by a neighbouring farmer, who rears them to beef.
The bulls that Michael keeps to rear are selected based on their pedigree, EBI, and their dam's yield and protein figures. They are subsequently sold as breeding stock to pedigree herds across the country.
Cows due to calf down are moved into straw-bedded calving pens, according to their due dates. As soon as they are born, the calves are given colostrum by stomach tube.
The aim is to give each calf around 10pc of its bodyweight in colostrum so, for most calves, this is three to four litres. A second feed of the same amount, also by stomach tube, is given within the calf's first 12 hours of life.
Once the second feed has been given, the calf is moved by wheelbarrow from the calving pen and brought to one of 120 individual plastic calf hutches. The straw-bedded hutches are laid out in a 80m x 90m stone yard.
The calves are bucket-fed warm milk in their individual hutches until they are seven or eight weeks old. From day seven to 10, the calves are also offered a small amount of home- produced calf ration that includes wheat, soya, citrus and rape.
They are not fed hay as they are bedded on at least 12 inches of barley straw, which they eat to encourage rumen development.
At eight weeks old, the calves are moved from their hutches to small batches of between eight and 10 calves per pen.
"We group them by size, which usually means by age, but we hold back smaller calves so they don't get bullied and they get a better chance to thrive," says Michael.
The calf hutches are washed out and aired, upside down, for at least two weeks before the next calves are housed in them, in order to reduce the risk of spreading infection.
"Depending on the time of year, the next move is to put the calves out to grass. This usually happens at 12 weeks of age and the calves are grouped in batches of 20-25 per paddock.
"I like to put them out on fresh grass, so ideally nice silage aftergrass or re-seeded paddocks," he adds. As they grow, the group size increases, usually reaching up to 50 calves per group at the age of six months.
All calves are treated for IBR at two weeks of age (intranasal), at five to seven weeks and later by intramuscular injection.
"Our system is quite labour intensive but calf rearing is a specialised job and we have found a system that works for us," says Michael. "Individual hutches require plenty of labour, but I believe you get less in the way of disease."