Three key things are needed to aid rumen development in calves during the rearing period: water, concentrates and a source of fibre.
Calves should have access to all three from an early age so that development of the rumen can begin.
This changes the calf from being monogastric to ruminant, and aids in the digestion of forages.
During the early stages of life, a calf is monogastric – making them more similar to a pig, rather than an older ruminant.
This means that they have a single-compartment stomach, and able to obtain the nutrients they need for growth from milk or milk replacer.
During the rearing period, it is vital that calves are fed high-quality whole milk, or a high-quality milk replacer.
Fibre
Calves should be given a source of fibre in the form of straw or hay, which should be in a rack and on the floor of the shed.
Most farmers prefer to use straw as a source of fibre for young calves during the rearing period.
Although many farmers are not fond of feeding hay to calves, they may have no choice this year.
As a result of straw shortages, farms that currently have straw will need to keep some for bedding.
Hay
Most farmers will have used hay at some point, and there will have been varying results and options.
This issue that many farmers have with hay, is the development of a pot belly or reduced thrive in the calves. Many farmers would be of the opinion that straw is the better option.
The issue in the majority of cases, is that the hay being fed to calves is of poor quality, or is late hay with a lot of older grass present.
If you are going to be using hay to feed calves, it should high quality leafy grass or early hay.