Calves suckling 20pc of weight
Suckler calves will suckle approximately 20pc of their bodyweight per day.
However, traditionally dairy calves have only been fed approximately 10pc of their bodyweight or around two litres twice a day.
The discrepancy arose for economic reasons, because it was believed that if calves were hungry they would start to eat concentrate creep feed at an earlier age, which is less costly than calf milk replacer.
However, this practise has been shown to have a negative impact on a calf's daily live weight gain, early calf health and the calves are less likely to meet the target weights for breeding etc.
Under perfect conditions (little or no stress or disease, low infectious pressure and housing that is neither too cold nor too hot) a 40kg calf could gain about 200g weight per day on 4l of milk per day.
However, not all calves are the average weight of 40kg and some heavier calves fed 4l of milk will not get enough to even maintain their weight.
There are also many situations in which calves need more energy, for example in colder weather (below 15°C), heat stress, disease, or after vaccination.
Under these circumstances, calves may be severely underfed.