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Feeding and Weaning Dairy Calves

A calf drinking large volume of milk can doubles its growth rate during the first 2 months of the milk feeding period.
Weaning this animal may present some challenges.

Traditionally in conventional systems, dairy calves fed milk have received 8 to 10 percent of their birth weight per day. In other words, a calf with a birth weight of 45 kg would have received 4.5 litres of milk per day. This was a typical feeding regimen when calves were housed individually and received 2 meals of milk per day. In recent years, things have changed substantially on many farms. With the advent of computerized feeding systems for calves, ad-libitum feeding, group housing and so on, most calves now consume a greater amount of milk. It is not uncommon for some calves to receive up to 12 litres per day.

During the milk feeding period, calves are now expected to double their birth weight in a 2 month period. Holstein calves are expected to reach 90 kg at 2 months of age. In order to achieve this goal, substantial amounts of milk need to be fed to the calves. Automatic systems come in handy since the number of meals needs to be increased.

In a recent study, an automated milk feeder was used to evaluate 2 milk feeding regimens: a limited milk allowance regimen (up to 4 litres of milk per day); and, the ad libitum regimen (up to 24 litres per day).

The calves that were allowed free access to milk drank on average about 8 litres of milk per day during the first 3 weeks in 12 visits to the feeder per day. The calves on the restricted diet drank half the amount of milk in twice as many visits and spent a lot more time at the feeder. This significantly affects the efficiency of the automated feeder since fewer calves can be hosted by the system. Furthermore, the concentrate consumption during the first 3 weeks of life was not significantly different between treatments, suggesting hunger in the calf group receiving the lower level of milk.

From week 3 to week 6, the calves increased their consumption of milk to about 10 litres per day, getting one litre per visit while the calves on the restricted regimen got 4 litres but they visited the feeder twice as often as the other group. During that period, the calves receiving low volumes of milk consumed significantly more concentrate, suggesting that these animals increased the concentrate intake in order to compensate for the lack of milk.

Increasing the liquid portion of the diet reduces concentrate intake during the milk feeding period. This may lead to reduced weight gain and even weight loss at weaning time, offsetting the benefit from the greater amount of milk fed earlier on. A specific weaning strategy may need to be implemented since the days following weaning are a stressful period for the calf. Minimizing stress will improve overall performance and will prevent an offset of the gains from greater amount of milk fed.

A recent study, where calves were weaned at 6 weeks of age was conducted in British Columbia. Although in an organic system, calves should receive whole milk until 3 months of age, the findings highlighted by this research project are of great interest for organic dairy producers.

This research project evaluated the impact of different weaning methods on calves weaned at 6 weeks of age. In that study, a groups of calves fed large mounts of milk was used to evaluate the impact of abrupt weaning compared to gradual weaning. Four different weaning duration treatments were evaluated: 22 days, 10 days, 4 days and abrupt weaning. Before weaning, every calf was allowed to drink up to 12 litres of milk per day. The first lesson learned from this trial is that when calves receive a substantial amount of milk, abrupt weaning is the least desirable strategy. Gradual weaning is a far better option since as the amount of milk offered decreases, concentrate consumption increases. Weaning calves over a 10 day period appears to be the best option to optimise weight gains. A long 22 day weaning period will have a detrimental effect on weight gain. A short 4 day weaning period appears to be insufficient to stimulate increased concentrate and forage intake.

Since on organic dairy farms calves are weaned at an older age, the optimal duration of the weaning period may be different, depending on the dry matter intake of these animals at weaning time. Nevertheless, abrupt weaning is probably not the best option anyhow.

Gradual weaning was not a popular method some years ago when feeding was done by hand. Fortunately, with computerized feeding systems, we can now program the feeder in order to decrease the milk allocation for a specific animal over a preset time period. Furthermore, these automated feeders can provide several meals per day to calves in order to optimise growth rate as well as animal welfare.

If gradual weaning is done by hand, a good feeding chart is quite handy. Some producers use a dry eraser board to record milk quantities to be fed to each animal.

Especially when it comes to gradual weaning, memory alone may not be enough to know where each calf it at in terms of quantities.

Objectives for the First 2 Months of Life

Double calf birth weight by day 60 of life
Mortality < 5%
Morbidity (treatment) < 10%

T.F. Borderas, A.M. de Passillé, J. Rushen. 2009. Feeding behaviour of calves fed small or large amounts of milk. J. Dairy Sci. 92:2843-2852

B.C. Sweeney, J. Rushen, D.M. Weary, A.M. de Passillé, 2010. Duration of weaning, starter intake, and weight gain of dairy calves fed large amounts of milk. J. Dairy Sci. 93:148-152