Calf Health Series: Maximising and monitoring performance through to weaning

In Part 7 of the ‘Calf Health Series’ – a joint initiative brought to you by AgriLand and Volac – we will outline set target weights for your calves throughout the first 12 weeks of life.

We will also look at different ways of monitoring performance during this period and focus on the weaning stage – an important period in the young calf’s life.

Doubling the calf’s birth weight by the time it is weaned is crucial. A 40kg calf at birth should weigh at least 80kg at weaning – i.e. it must put on 40kg by weaning or 0.7kg/day.

Weaning calves based on their body weight will help ensure a uniform group of calves at weaning. It also means that post-weaning management will be much easier. Therefore, regular weighing must be carried out through this period, as body size cannot be accurately determined by visual assessments.

Calibrated weighing scales offer the most accurate and simplest method (if set up correctly in a race or crush) to measure body weight.

However, they may not be present on every farm. If this is the case, a weigh-band is an alternative and cheaper option.

Heart girth is closely correlated with weight, so measuring heart girth in centimeters – using a weigh-band – will provide reliable measurements.

All calves should be weighed at birth and at six months at an absolute minimum. Weighing could coincide with another management practice, such as worming or vaccination, for a more efficient use of time and to minimise stress on the calf.

How to use a weigh-band correctly:
  • Restrain the animal securely;
  • Place the weigh-band over the animal’s back just behind the front legs;
  • Pull the weigh-band under the animal’s belly using a reaching hook;
  • Read off the animal’s weight by lining up the reading line with the weigh-band scale;
  • Do not overtighten the weigh-band – just flatten the hair.

In previous articles from this series, we have detailed what and how much to feed during the first 12 weeks, and explained – whether you are rearing a heifer or a high-performance beef calf – how opting for higher milk replacer intakes early on results in improved feed conversion efficiency (FCE) and better growth rates.

As we now know, feeding calves high volumes of milk helps them to achieve their early growth potential – and this is beneficial for their lifetime milk or beef production.

However, calves that are fed more milk will not be driven by hunger to eat solid feed, since their hunger will be satisfied by the milk. Consequently, they may eat less starter.

But, high milk fed calves can be encouraged to eat solid feed by implementing management strategies (such as the location of feeders and starter troughs) – balancing the intake of nutrients from both milk and solid feed.

The calf is born with a non-functional rumen – nutrients from milk (milk sugars – glucose) are digested in the abomasum and intestines to supply the calf its energy.

The rumen must be sufficiently developed at weaning, so that it can digest and utilise solid feed – replacing the nutrients previously supplied by milk, giving the calf its energy to grow. Rumen development is largely driven by the fermentation of calf starter by the rumen bacteria.

Also, offering forage alongside starter feed plays a role in rumen development – it helps stabilise the rumen pH, stimulate the muscular layer of the rumen and maintain the integrity and healthiness of the rumen wall.

Therefore, providing chopped barley straw (separately from starter) during the milk-feeding period has been shown to stimulate starter intake, improve weight gain and improve forage intake after weaning due to the calves’ increased ability to ingest and digest forage.

If chopped forage is not available, provide long fibre by offering forage in racks (a separate source from the bedding).

If a calf is being fed enough milk and starter, it will naturally limit its forage intake, but – as a guide – forage intake should be less than 5-10% of the total dry feed intake (i.e. about 0.1kg/day of forage as weaning approaches).

The weaning period

Volac advises gradually reducing the amount of milk (≤750g of milk solids/day) offered to calves, over a three-week period between days 35 and 56 (see table below).

This encourages starter intake, helps rumen development and improves the ability of the calf to digest nutrients after weaning. While ‘weaning for weight’ is important, generally speaking calves should be consuming at least 1-1.5kg/day of starter prior to weaning.

Starter intake will rapidly increase at weaning, when milk is removed.

But, a rapid increase in starter intake at weaning does not allow enough time for the rumen to develop – the amount of starter that has been consumed for three weeks before weaning is key for rumen development.

Calves that are fed more milk over the first five weeks of life will be bigger and more vigorous. These calves will subsequently eat more starter when milk is gradually reduced from day 35 to 56.

Below is the recommended milk feeding plan with a three-week weaning period (for calves fed twice daily). The stepping down period is shaded orange.

Try not to be left with a few smaller calves in the post-weaning group. It is much better to correct this before they are weaned.

The reduction in milk solids per day will be specific to each individual dairy farm. For detailed advice on stepping down milk powder feeding levels on your unit, please speak to your local Volac Business Manager.

Part 1: Calf Health Series: The power of colostrum must not be underestimated
Part 2: Calf Health Series: What should I feed, and how much, for optimum condition?
Part 3: Calf Health Series: Which feeding system is best suited to your farm?
Part 4: Calf Health Series: Hygiene and biosecurity must not be overlooked in the calf house
Part 5: How to provide the perfect environment for calves
Part 6: Calf Health Series: Why feed conversion efficiency is highest during the pre-weaning period

More information

Volac has been involved in young animal nutrition for the past 40 years and is an innovator in this field.

The company is committed to helping farmers make the most of their calves and has developed a range of specialised milk replacers, which are specifically formulated for modern dairy and beef animals.

For more information, contact a Volac representative today, or visit the Volac website by clicking here