Weaning is a slow gradual process which typically begins when replacement heifer calves reach eight weeks-of-age, meaning the process will be commencing this week for farms that begin calving in or around February 1.

Many farms often choose to feed for a further two weeks, but either way the process must be gradual.

If they are not weaned gradually, the calf’s digestive system can become stressed, which can lead to further issues such as pneumonia and stunted growth.

A successful weaning process is important, as this is when a calf transitions from a monogastric to a ruminant animal, and begins getting most of their nutrients from solid food, such as grass, straw, hay, or concentrates.

A successful weaning should strike a balance between achieving adequate growth rates in your calves while promoting rumen development.

Successful weaning

After four weeks-of-age, a lot of farms move calves to once-a-day (OAD) feeding, this practice not only reduces the workload during the busy spring months, but can also significantly help with the weaning process.

Despite milk replacer often being associated with OAD feeding, studies have shown from 28 days-of-age, whole milk or milk replacer can be fed once-a-day with no difference in weight gain or scour incidence.

However, feeding protocols need to be kept accurate, while the calves will need access to clean, palatable concentrates and 4-5L of clean fresh water for every 1kg of concentrates consumed to help ensure bacterial growth.

Once the calves are eating at least 1kg of starter concentrates/day consistently, the amount of milk being fed can be gradually pulled back and replaced with additional concentrates each day.

The more concentrates you can get them to eat before completely ending milk intake, the better, however intake will depend on the availability of concentrates and the volume of milk being fed.

If you are feeding milk replacer this spring, it is important to reduce both the solids content and water content of milk at the same time.

Weaning should take a minimum of two weeks, however farms that are using automatic calf feeders may need up to four weeks.

Target weights

Waiting for calves to be consistently eating 1kg of concentrates is one way to go about weaning, as it indicates a sufficiently developed rumen.

However, its also a good idea to weigh the calves around this time, ensuring they have reached approximately 15% of her target mature weight before weaning.

The predicted mature weight and target weaning weight of replacement heifers are as follows:

Weighing calves is always recommended to ensure they are hitting their target weights at stages such as weaning, however a lot of farms are happy going off a simple visual assessment of the calf.

The main thing to remember when weaning is that calves don't respond well to sudden changes, as it causes stress and can affect their health, so, consistency and a gradual transition is vital.