The primary reason for shortening the breeding season is to tighten up the following calving season. This is to increase profitability and simplify workload during the coming year.

Many farms will choose to operate a 12-week breeding season, which then reduces the length of the calving season. Herds with a very spread out calving pattern generally can’t afford not to milk over the coming winter, according to Teagasc.

Nationally an average of 389,000 cows or just over one quarter of ‘spring-calving’ dairy cows calved between April and June in 2019 and 2020. Teagasc’s target is that only 10% of spring-calving cows should calve in the period – and those should calve in the month of April not in May and June.

The reason for this is to maximise the proportion of grazed grass in the cow’s diet. For this to happen, February calving is the best month.