For farms that start calving in mid-January it may now be time to start looking at potentially weaning some of the older calves.
The weaning process is important as a calf moves from a monogastric to a ruminant animal.
This is where the calf goes from getting most of their nutrients from milk to solid food such as grass/silage/hay or concentrates.
Rumen development
During the first weeks of life, a calf is entirely dependent on milk as a source of nutrition,
with the digestion of milk occurring in the abomasum. Young calves have little to no rumen capacity in early life.
Careful nutritional management before weaning ensures that the rumen develops to allow the transition to an entirely solid diet.
Successful weaning is a balancing act between achieving an adequate growth rate and promoting rumen development.
To promote rumen development in calves it is important that they have access to a palatable starter concentrates as soon as possible.
They will likely only eat a very small amount for the first few weeks of life.
But providing a smallm fresh amount every day reduces wastage, encourages calves to eat and allows you to monitor intakes.
Calves fed coarse starter-mixes initially eat more and have greater weight gain than calves fed pelleted starters – the coarseness is also of benefit for the growth of the muscle layers in the rumen wall.
In addition to a ration, calves need to drink water to help ensure bacterial growth.
A calf requires 4-5L of water for every 1kg of concentrates, so provide calves with clean, fresh water at all times.
Weaning calves
Weaning should begin only in a healthy calf that is consuming at least 1kg concentrate feed/day.
Ahead of weaning calves should be transitioned onto a once-a-day (OAD) feeding regiment.
You should not water-down milk replacer or whole milk prior to weaning. Instead, reduce the volume calves are being fed to encourage increased consumption of concentrates.
The aim is to moves calves onto OAD feeding approximately one month prior to weaning to allow calves time to adjust to the new regime and further develop their rumen prior to reducing total liquid feed amount.
Once they are accustomed to OAD feeding daily and consuming 1kg of concentrates consistently, the reduction in milk feeding can begin.
In automatic feeding systems, calves can be weaned more gradually. The weaning protocol again starts about a month before weaning and the amount fed is reduced gradually until they are weaned.
Target weaning weights for replacement heifers are based on their mature weights or maintenance figure within their economic breeding index (EBI).
Weaning can safely take place when the heifer has reached approximately 15% of her target mature weight.