Maiden heifers from the dairy herd are some of the worst affected stock in the current fodder crisis, according to Munster AI's Doreen Corridan.
While the target weight for breeding heifers is 340kg, Ms Corridan believes a significant proportion of animals are not near this target yet.
Data from the ICBF already reveals the number of animals artificially inseminated so far this year is back 15pc.
"This is probably due to some farmers pushing back breeding dates, but also because there were just fewer cows detected in heat for serving," commented Ms Corridan.
However, she believes that maiden heifers have suffered even more severely this year.
"Cows have been prioritised with the result that many heifers are still inside and more are underweight," said Ms Corridan.
While the optimal target liveweight for breeding maiden heifers is 340kg, Ms Corridan believes that heifers of more than 300kg in weight should still be bred immediately.
"Farmers should not delay breeding for three weeks since that will only increase liveweights by 20kg. Instead, they should be bred now so that they calve in mid-February.
"At the same time, if they are on good grass they need to be getting 2kg/hd of a heifer rearer ration, and 4-5kg/hd if they are still indoors on poor quality silage," she said.
The breeding expert also advised farmers to reprioritise grazing for these heifers for the next three months before reintroducing a supplement ration to ensure they catch up during the summer months.
"There will be a big growth in grass at some stage, but it is important that farmers allow their young breeding stock to benefit from this," she warned.
She also recommended that farmers use a very easy calving bull on the stock, "because they will need to be fed on throughout the winter," she said.
Munster AI are rolling out a fertility programme across 10,000 cows this year in conjunction with local vets and Teagasc.