Ensuring a successful weaning and transition to grass

Concentrate Supplementation

To reduce potential stress, concentrates should be introduced early, from a few days of age, to encourage intake. A high-quality, palatable starter concentrate should be available to calves freely, as soon as they arrive on farm, and offered fresh daily.  Concentrates should be highly palatable and of a high nutritional quality with good quality ingredients. Finely ground, dusty feeds should be avoided as this will reduce intakes. Calves fed coarse starter mix initially eat more and have higher weight gain and make the transition better. Calves should only be weaned after they have been eating a high volume of meal. Ideally calves should at least 1.5kg of starter concentrates or more per day for at least three consecutive days prior to weaning. This level of intake is usually achieved by eight weeks of age.

Forage Supplementation

Forage supplementation is beneficial to aid with rumen development, but not near as fundamental as concentrates.  Calves need small amounts of roughage in order for the rumen to develop.  Straw is an easier roughage feed for calves to digest and is preferred to hay. A high intake of hay in young calves will decrease the intake of concentrates, and the calves will often develop ‘pot bellies’. Over consumption of straw should be avoided as this reduces the overall energy density of the diet and will negatively affect performance.

Before weaning calves should be healthy and not stressed if there are any issues with them the milk feeding should be prolonged. Any stressful events such as castration, disbudding or vaccination should be avoided at this time as it will cause upsets and could potentially cause a growth check after weaning. Calves can be either abruptly or step weaned. Stepped weaning is when the amount of milk being fed and the number of feeds/day are gradually reduced over time.

This is also referred to as gradual weaning. Both step weaning and abrupt weaning can be performed successfully provided the calf’s rumen is adequately developed and that they are eating at least 1kg of calf ration per day.

However, stepped weaning does reduce the stress at weaning and can avoid temporary setbacks in growth rate

Generally, stepped or gradual weaning is achieved by reducing the volume of milk fed over a period of seven to 10 days. If calves are being fed milk twice a day, weaning can be achieved by cutting down to once a day feeding.

Preventing that post weaning growth check

The post-weaning growth check found in many calves is due to three factors

Low intake of dry feed up until weaning, resulting in limited rumen development. This results in a growth check for about two weeks while the rumen becomes accustomed to digesting significant quantities of dry feeds.

High intake of bulky roughage such as grass and hay. Calves are physically unable to eat enough roughage to sustain rapid growth weights with their small, developing rumen.

Calf stress when feeds are changed. Feeding concentrates before, during, and after weaning should limit the level of growth check. If a growth check does occur, the lost growing time will never be made up and it will take longer to attain target weights.

Only correctly weaned and healthy calves consuming at least 1.5kg/day of concentrates should be turned out to pasture. A well-sheltered paddock should be targeted to acclimatise calves to the outdoor setting, turning calves out in unfavourable weather conditions in extremes of warm, wet or cold should be avoided as potential upsets could result. Ideally if the fields in which calves are turned out each year first could be alternated to avoid the build-up of pathogens and diseases but this is not always practical. Paddocks that have had high levels of nitrogen applied or have very lush covers should be avoided immediately post turnout to prevent any digestive upsets. Once calves become acclimatised to the outdoors grass pre-grazing covers of <1,000kg DM/ha should be targeted to encourage intakes. Offering calves straw for 5-6 weeks post turn-out can also beneficial as it will provide a source of fibre especially where grass covers are lush, but this not near as fundamental as concentrate feeding.