Tradition of calving heifers at three years still practiced on some farms

An ICBF investigation of 160,334 dairy calvers in 2014 has confirmed the Teagasc recommendation to calve heifers at 22-26 months of age.

It revealed that the tradition of calving heifers at three years is still practiced on some farms, and ICBF said these are the herds that need to be targeted to promote the benefits of calving at two years of age.

The findings highlight that calving at 22-26 months is best for increased lifetime yield and increased profitability.

First lactation milk production was lower among younger heifers, but lifetime daily milk yield was significantly increased.

Sustainability is also improved, with cows lasting longer in the herd, thus reducing the replacement rate, and preventing the additional unwanted methane emissions from older calving heifers.

Nearly one third of the first calvers at 22-26 months survived into the sixth lactation, whereas only 11% of the first calvers at 27-32 months lasted for six lactations.

When survival is incorporated into milk production, the lifetime milk yield of first calvers at 22-26 months was significantly increased.

The difference in the net financial outcome between first calvers at 22-26 month and at over 32 month was €307, or a loss of €30,700 in a 100-cow herd, by not calving heifers between 22-26 months.

ICBF researchers said it is positive to see there has been an increase in the percentage calved at 22-26 months (from 50.8% in 2005 to 69.3% in 2015) but there is still a large area for improvement.

The study of optimum age at first calving was carried out by ICBF’s Susan Moriarty.