Heifer calf targets must not be forgotten about in the midst of breeding and silage cutting season, as many calves are still only getting used to grazing fresh grass.
It is important to look out for calves scouring or falling behind the rest of the group, as quickly identifying these calves will mean they can be segregated, given extra meal and hay or straw, allowing them to catch up to the rest of the group.
Meal feeding should be maintained post-turnout for at least five to six weeks to help the calves transition to eating grass at a feeding rate of 1.5-2kg of meal/head/day.
Be careful of letting calves out to the same paddock year after year, as altering the paddock will help avoid the build-up of pathogens and diseases.
Paddocks that have recently received high levels of nitrogen (N) or are very lush and protein-rich should be avoided at turnout to avoid any digestive upsets.
Summer scour often occurs when calves are grazing lush pastures with a high crude protein (CP) content (>20%) and a low fibre content (<40%).
At turn-out, calves should have access to a fibre source in the form of hay or straw in the paddock to counteract the high CP they eat in the grass, as calves are selective grazer and will only eat the lush stuff first. Strip grazing is also advisable.
Heifer calf targets
Calves should not be left in the same paddock for long periods of time as it is important to rotate calves on a regular basis to ensure fresh grass ahead of them.
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.
The only true way of making sure your calves are on target is through regular weighing every couple of weeks, maybe at a time where you are getting them up to dose or vaccinating.
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). To get a better understanding, farmers could weigh a couple of their mature cows and work off that figure.
Poor fertility in replacement heifers often occurs when they 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. It is easier to get a calf at three or four months-of-age back up to speed than it is a heifer close to bulling.
Keeping on top of weighing is important but regular handling and monitoring means you will 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. This should be discussed with your vet, especially after a long period of dry and warm weather followed by heavy rain.
