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Factors to consider before weaning Weaning challenges Rumen development Weaning weight Competing within a group Weaning Process Relocating recently weaned calves

Successful weaning based on calf weight and meal intake will help calves develop into healthy heifers. It's important to ensure calves are consuming the right amount of feed and meeting their weight-for-age targets. Weaning can be stressful due to dietary changes and exposure to new environments. To avoid health issues, changes in diet and living conditions should be done gradually and monitored closely. Rumen development, achieved by feeding at least 1kg/day of meal or 2kg/day of pasture, is crucial. Your calves should reach a minimum weight before weaning, which varies by breed. Post-weaning, monitor weight gain and health closely.

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:

  1. Their main source of nutrients switches from liquid to solids
  2. 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

• Fully weaned and off milk for at least two weeks

• Competing in the mob

• Meet minimum weight target

• Drenched and vaccinated

• In good health

• Transitioned onto a full pasture diet or supplement provided for transition

• Mob average meets weight-for-age target, grazing together as a group, prepared for transport

• Lightest animal within 10% of mob average, assuming they are a similar breed

Last updated: Sep 2023
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