Replacement heifer calves that were born in January and February should now all be at grass and weaned from milk.
Although much of the heavy work is over with regards to calves, a focus very much still needs to be placed on their management at grass.
Much of the fertility issues with heifers are due to them failing to reach growth targets in the lead up to mating, but this can be avoided if good management practices are implemented.
Calves
The first grazing season is vital for reaching growth targets and becoming strong members of the milking herd in the future.
When grazing, calves should be moved every three days, with best practice being to operate a ‘follow the leader’ system, according to Teagasc.
This system allows young calves to graze a paddock with bulling/in-calf heifers then grazing/cleaning up afterwards.
When they are initially turned out to grass, they will have an intake of 2.5kg/dry matter (DM)/day, with this increasing to 5kg/DM/day by housing.
If you have 40 calves, they will require 360kg of DM for three days grazing (3kg/DM x 3 days x 40 calves).
Parasites
Monitoring parasite burdens in calves should also be a priority while they’re at grass.
Dosing should not be taking place unless dung samples have been taken. It is recommended for worm burdens that are above 200 eggs/g, but a vet should be consulted before dosing.
Rotational grazing will help to prevent exposure to parasites, but if paddocks or fields have a large build-up, the removal of grass for silage or reseeding is a good way to reduce worm build-up in paddocks.
Ideally, the replacement grazing block should be at a stocking rate that allows for paddocks to be removed for silage.
Reseeding is not only a good way to improve grass quality on the replacement grazing block, but it also helps to reduce parasite build up.
Growth rates
The calves’ maintenance figures will determine the mature weight of the animals.
Farmers should continue to monitor the growth performance of their calves on a regular basis.
They should be weighed to determine if they are achieving their targets.
Farmers should also be closely monitoring them for any signs of ill health or other issues that may affect them.