Since the weather has improved, any farmer that did not have calves out already, has been able to get them out over the last week or two, and now, heifer calf targets must be considered.
Post-weaning, a lot of the hard work is done, however, it is still important to closely monitor their growth performance and manage their grazing.
Rotational grazing in a leader/follower system is optimal, with calves grazing ahead of yearlings.
However, this is not always possible. Calves are selective grazers, so, ideally, fresh grass should be available to them.
As well as that, calves should not be left in the same paddock for long periods of time.
Rotate calves on a regular basis to ensure fresh grass ahead of them. Early spring calves should be off milk and on a diet that consists of grass and concentrates.
Achieving heifer calf targets
Calves should be grouped on size, and in the case where a calf falls behind, the calf should be moved to a more suitable group.
Calves should be weighed on a regular basis in order to ensure that their growth targets are being achieved.
Having individual weights for each calf is important. Avoid focusing on the average weight of the group, as it may hide a number of calves that have fallen behind.
The main targets for heifers are:
- 30% of their mature body weight by six-months-of-age;
- 60% of their mature body weight at bulling (15 months);
- 90% of their mature bodyweight when they first calf at 24 months.
The mature weight of a calf can be determined by its maintenance figure within the economic breeding index (EBI).
Monitoring health
Poor fertility in replacement heifers often occurs when heifers are underweight at mating start date, but this can be easily avoided if weight and weight gain of the heifers is regularly monitored.
By regularly monitoring weight performance, you will be able to pick up on any calves that are sick or behind.
Identifying calves that need treatment on time will allow them be on target and keep up with the rest of the group.
This will also allow you to be able to monitor any health issues and pick up on cases of summer scour or coccidiosis, before they turn into a major problem.
A good worming programme should also be considered during the summer months.
