Along with milk, concentrates and forage, water is critical in the calf rearing process and in the early life of calves.
When a calf is first born, they are dependent on a milk diet in the form of whole milk or milk replacer after the initial feeds of colostrum and transition milk.
With age and the appropriate diet, the rumen begins to develop. The rumen is the engine which drives production from the grass-based diet of dairy cows.
However, the rumen takes time to grow and an appropriate diet needs to be fed gradually in order for the rumen to develop and be functional.
The offering of concentrates in the calf shed is completely down to the farmer and the calf will do the rest – concentrates and water are crucial for the development of the rumen.
Water
Water and starter ration are crucial for the development of the rumen and the two are dependent on each other, as the rumen needs the bacterial fermentation of of the starter concentrate and fermentation is dependent on the presence of water in the rumen.
Calves will require 4-5L of water and 1kg of concentrates fed, and so all water troughs should be checked to ensure they are in reach of calves and working properly.
During the fermentation process, butyric acid is produced and it changes the surface of the rumen from a smooth surface to a rougher surface (papillae), and this increases the surface area of the rumen, which is crucial for the absorption of nutrients.
Calf weaning should only occur when a healthy calf is consuming 1kg/head/day and before this calf should have access to a palatable calf starter and eventually offered it on an ad-lib basis.
High total milk solids in milk replacer can alter the osmotic balance in the calf, as water is pulled out of cells which can result in diarrhoea and dehydration.
However, when fresh water is available to the calf, it allows the calf to regulate their osmotic balance, which will lessen their chances of dehydration.