Milk replacer key to increasing calf weight

Getting pre-weaning nutrition right in calves will go a long way towards achieving future growth targets.

Recent research data shows a 130kg increase in a cow’s 305 day milk yield with each 100g/day increase of average daily gain (ADG) in the pre-weaning period. With this theory in mind, if farmers can increase ADG in the pre-weaning period from 500g to 800g/day, this could mean an extra 390kg of milk, or about 32kg MS per cow.

Increasing ADG can be achieved by feeding a high-quality calf milk replacer (CMR) with nutrient densities which are above traditional rates. Graph 1 shows a traditional view of feeding 1% of body weight with a lower nutrient density CMR (20:20, protein:fat) compared with a modern view of feeding 1.5% of body weight with a CMR containing 28% protein and 22% fat, like MaxCare Ultimate CMR.

The first graph also demonstrates that temperature can have an impact on ADG. A 40kg calf fed 10% of its body weight, in other words, 4l/day at 20 degrees Celsius – the thermo-comfort zone of a young calf – will at best gain 400g per day.

The same calf at 0 degrees Celsius will potentially lose weight. For every five degrees Celsius drop below 20 degrees Celsius, calves require an extra 1.1 megajoules of metabolisable energy to achieve the same result. This is the equivalent of an extra 50g/day/calf of CMR.

An understanding of desired mature cow body weight (MBW) to determine the growth rate required for calves is also important.

In the first six months, 50% of a calf’s skeletal growth occurs and the aim should be to achieve 85% of MBW soon after its first calving. To achieve this, these are targets to aim for:

  • Weaning weight: 17% of MBW.
  • Six months: 30% of MBW.
  • Joining (15 months): 60% of MBW.
  • Pre-calving (22 months): 90% of MBW.


The feed conversion ratio (feed:growth) at the different stages of life should also be a consideration for calf rearers.

The ratio ranges from 2:1 between birth and weaning and up to 15:1 from mating to late pregnancy. Given the efficiency of growth in the birth to weaning phase and the on-going implications of calf rearing on lifetime productivity, investing in calf nutrition is worthwhile.

  • Find out more, call MaxCare on 0800 629 267.