Making sure a heifer is fully prepared before weaning reduces the chance she will need preferential treatment post-weaning. Preferentially managing small groups of animals to try and "catch them up" to the group is time-consuming and can be difficult to manage, so it is best avoided by good early management.
Factors to consider before weaning
Is the calf:
- Consuming the desired amount of feed? Is its rumen sufficiently developed?
- Meeting its weight-for-age target, based on its breed and/or the rearing system?
- At the minimum age for the rearing system?
- Able to compete within a group?
Weaning challenges
Weaning can be a challenging time for a calf for two main reasons:
- Their main source of nutrients switches from liquid to solids
- They are exposed to new bugs as they enter new environments
Calves can become stressed from changes in housing, competition in new groups, and general husbandry practices (e.g. diet changes, vaccinations, etc). Weaning will be more successful if your calves are only exposed to one stressor at a time.
Rumen development
A calf's rumen development is the most important factor to consider when making the weaning decision. The only way this can be assessed is by measuring the amount of concentrate or pasture they are readily eating, which should be at least 1 kg/day of meal or 2 kg/day of pasture.
Any change to the quantity or type of feed needs to be measured. Just as it takes time to develop the rumen, time is key in transitioning from calf meal to a full pasture diet. Farmer experience indicates that a two-week gap between each diet change (e.g. weaning off milk with meal concentrate to full pasture diet) will help transition calves to a full pasture diet.
Nutritional guidelines for calves
New-born calves have high dietary protein requirements, this requirement declines as they age. A higher crude protein intake should lead to higher growth rates. If using calf meal, look for products that contain 20% crude protein for calves on milk and 17% crude protein for weaned calves to meet total dietary requirements.
|
Calf weight (kg) |
Liveweight gain (kg/day) |
DM intake (kg/day) |
ME (MJ/day) |
% of crude protein (CP) in diet |
|
45 |
0.6 |
0.9 |
15 |
25 |
|
55 |
0.8 |
1.2 |
21 |
23 |
|
70 |
0.8 |
2.0 |
26 |
18 |
|
90 |
0.8 |
2.5 |
30 |
17 |
Weaning weight
Individual heifers should reach a minimum weight prior to weaning. Although no specific weaning weight has been defined by research, the type of rearing system will affect the target weaning weight. Common weights used for weaning are 70kg for Jerseys, 80kg for Fr x J Crossbreds, and 90kg for Friesians.
Competing within a group
Heifers need to be competing with the group before they are weaned. Any that are not should be held back.
Weaning Process
When weaning calves off milk, it is recommended to use a gradual or stepwise process, removing milk slowly over 1-2 weeks. This will allow the calf time to adjust to the lower level of milk and increase solid feed intakes accordingly. Be sure to monitor calf behaviour and meal intake over this time to identify any calves that may be struggling.
If the calves have been eating meal whilst on milk, keep the meal in their diet for at least two weeks after weaning from milk. This will help to reduce the growth check as their rumen adjusts to digesting higher levels of pasture. After 2 weeks, if pasture supply and quality are adequate to meet your desired growth rates, meal may also be removed.
Sometimes animals do not thrive post-weaning so weigh them within 7-10 days to make sure they have gained weight from weaning. If they’re not thriving post-weaning they may need continued access to calf meal, regardless of weight or age.
Relocating recently weaned calves
Relocation can result in growth checks or be a trigger for animal health issues including pneumonia, scouring and parasites.
Recently weaned calves are at particular risk as they will be undergoing changes in diet, rumen development, and may be moving from individual or small group care to larger mob management. Relocation adds to the risk; the younger the animal, and the more recently they have been weaned, the higher the risk.
|
Relocation criteria |
|
|
Individual animals |
Mobs |
|
|
