Fertility is key to achieving a six-week 90% calving rate and farmers should focus on the EBI’s sub-fertility index when making breeding decisions this spring, according to Teagasc’s Stephen Butler.
The Teagasc Principal Research Officer said that the fertility index is important and a cow with a high rating will be more likely to go in calf and calve within the desired six-week period.
“Cows with a high fertility sub-index hold condition better and also show better signs of oestrus, which makes it easier to spot these cows at bulling.
“At some point, this spring farmers are going to have to pick bulls. The vast majority of dairy farms have a long way to go to achieve a 90% six-week calving rate.
The target herd fertility sub-index is €140, but most herds are well below this.
Butler also said that farmers have a lot of choice when it comes to picking high fertility bulls to improve the overall fertility levels of their herd.
ICBF’s active bull list shows that the average bull on this year’s list has a sub-fertility index of €164. This is considerably higher than previous years.
However, Butler also said that farmers should focus on the management of their cows and simply increasing the fertility of the herd is not enough to have 90% of the cows calving down over six weeks.
Source: ICBF
Get your heifers calved down early
Another area where farmers can make improvements to their six-week calving rate is through the management of heifers.
Butler said that heifers should be the correct weight at the time of breeding. Teagasc research shows that the ideal weights for heifers is 60% of their mature weight.
He also said that farmers should target having their heifers calving first.
“Whatever heifers are not bred within the first six days of the breeding season should receive a shot of progesterone. This will only work if the heifers are already cycling.
“It is easier to deal with heifers a week-to-10 days before cows start to calve.
There is an advantage to having your heifers calving earlier, as all of the heifers will be cycling by the start of the breeding season.
“The decision to bred heifers earlier is all about management, but it varies from farm-to-farm,” he said.