Calving at two: essential for herd profitability

Dairy cows don’t become profitable until halfway through their second lactation. True or false?

True. It’s a fact that each of your heifer replacements is costing an average £1,800* to rear to first calving, a figure which represents around 20% of farm costs and the second biggest expense on your unit. So the sooner they calve, the sooner you’ll get a return on that massive investment, particularly since the return on that initial investment is not earned until at least the second lactation.


If you target 24 months age at first calving, then your heifers will achieve 10 months more profit producing production than one calving at 30 months which won’t break even until well in to their third lactation.

That’s not all, heifers calving at 24 months have better fertility, they have higher milk yields and have the highest survival rate over a five year period, and consequently fewer replacements will be required leaving surplus heifers which can potentially be sold as an additional income stream. Irish studies have concluded that calving at 23 to 25 months old resulted in, up to an extra £2,300 of milk income per cow over five years when compared to calving at 30 months.


The following table, Figure 1 offers some pointers to achieve the 24 month calving target.

Fig 1: Essential growth targets
Birth to weaning Double body weight
Puberty 45% mature weight
Breeding and pregnancy 55 – 60% mature weight
First lactation post calving body weight 82 – 85% mature weight

Your goal is to achieve 82 – 85% mature size at first calving and achieving a first lactation yield of 80% of the mature cow. For mature weight, that figure is determined at the middle of the third and fourth lactation, 80 to 200 days in milk on healthy cows, not culls.

  • If your heifers have yet to calve in the 23 to 25 month bracket, then take a look at our new tool kit, Feed For Growth which is designed to help all dairy producers grow better cows. The programme enables you to create your own heifer road map which sets individual farm objectives and helps you to track performance and continually review to ensure each animal is on target to reach puberty by nine months, first breeding by 13 to 14 months and in calf by 15 months.

*A.C. Boulton, J.Rushton & D.C Wathes

Weaning – a guide


Weaning is the point when calves transfer from a liquid to solid diet. Weaning can be carried out successfully only when the rumen has developed sufficiently to support the fermentation and digestion of solid feed.

Here’s four factors for successful weaning from any rearing system

  • Fresh water available at all times – to encourage rumen development.
  • High quality starter feed available but offered in small quantities fresh each day.
  • Access to long fibre, for example straw in racks to encourage solid feed intake.
  • Eating minimum 1kg of solid feed daily for three consecutive days.

Rumen development can be influenced by diet

  1. Irrespective of your type of rearing system, easy access to fresh water and calf starter from the beginning of the rearing period will aid earlier rumen development.
  2. Introducing ad lib, clean straw – preferably barley will encourage a healthy well developed rumen.

When to wean

Rather than agreeing a fixed time, weaning is best done when the calf is consuming a minimum daily target of 1kg of solid feed for three consecutive days. Some calves achieve this at around five weeks, whilst others will take almost eight weeks. Remember that your calf naturally consumes milk for at least this length of time. A minimum target of doubling the calf’s birthweight should be achieved before weaning.

You can adopt one of two weaning strategies:

Abrupt – immediate switching from liquid to solid diet

This method can lead to significant growth setbacks if the calf’s rumen has not developed sufficiently to digest and utilise solid feed efficiently at this stage. The result is that the nutrient uptake from the solid feed cannot completely replace the nutrients previously supplied by milk.

Remember, if a calf is consuming 1kg/day of solid feed and four litres of milk at 12.5% concentration one day before weaning, it needs to consume almost 2kg/day solid feed the day after weaning to replace the energy previously supplied by the milk.

Abrupt Weaning_v2 TW

Step – gradual reduction of liquid milk over a period of time

An alternative weaning strategy designed to minimise the potential set back at weaning. Trial findings at Writtle College concluded that by stepping down the amount of milk fed and number of milk feeds per day over the last two weeks, the solid feed intake was increased and the efficiency of gain and economic performance was improved. These trends are linked to improved rumen development at weaning, resulting in a smoother transition onto solid feed without a growth check during this period.

Step Weaning_v1 TW

The following is an ideal step weaning system to consider

Twice daily feeding rates (125g per litre)
Age am pm
0 to 3 days Colostrum Colostrum
4 to 7 days 2.0 litres 2.0 litres
8 days to start of weaning 2.5 litres 2.5 litres
Weaning period (7 days) 2.5 litres 0

Minimise stress

Stress can influence the calf’s immune system; step up stress and it can increase the animal’s susceptibility to disease. Avoiding too many lifestyle changes at one time will help your calves to cope more readily with weaning stress. For optimal performance, try not to alter accommodation, solid and liquid feed, water and social group all at the same time.