By Karen Stewart, nutritionist, SAC Consulting

When and why spring-born suckled calves should be introduced to concentrate is always a hot topic of conversation but with this year's prolonged dry hot weather and shortage of grass, additional feeding is more important than ever.

Why to creep feed spring born suckled calves?

When a calf is four months of age, half of its nutritional requirements should be met by forage and concentrates rather than milk. Supplying creep feed before weaning can help smooth the transition from pre- to post-weaning and the extra source of nutrients can compensate for the reduction in milk yield as lactation progresses.

• Weaning weights can be increased by around 25kg, which helps get calves away

• Weaning check lowered through less stress from weaning – familiar with concentrate feed and rumen microbes are adapted for a change in diet

• When there is less stress at weaning there is a reduced incidence of pneumonia.

• Most efficient age for converting feed to kilos

Creep feeding is extremely efficient owing to the calf’s high potential growth rate. Since the rest of the calf’s diet (i.e. milk and forage) already more than meets the requirement for maintenance, all the nutrients from the creep are used for growth. This means that the conversion of creep to live weight gain is efficient at around 4kg feed/kg gain and is economically worthwhile.

When to start creep feeding

Timing will depend on calf age, growth potential of calves and grass availability. Normally creep feeding would start 6-10 weeks prior to weaning but bulls to be finished on ad-lib cereal diets should start being creep fed earlier, around 12 weeks before weaning. With very milky cows or in situations where it is tricky to creep feed starting 4-6 weeks before weaning will still help minimise weaning check. As a rough guide, allow 100-150kg of creep feed per calf for a 6-12 week creep feeding period.

If suckler cows are in poorer condition than normal, creep feeding will improve calf performance and take pressure of the mothers. If grass supplies are limited then creep feeding will also improve calf performance.

Some farmers have success with creep grazing with electric fencing using some tall posts every now and then so calves can creep graze ahead of the cows. Creep gates can also be used into adjacent fields as well so calves get access to better grazing. This is quite simple and can be used to gradually wean calves. However, as with any creep system there needs to be a size differential between cows and calves for access.

Type of feed to use in calf creep feeders

In summer, calves will be consuming milk and grass so on average a creep feed with 14-16% crude protein (as fed) and 12.5MJ metabolisable energy/kgDM should be adequate. As creep feed is usually made available from a feeder with a hopper it is effectively available ad lib so care is required to prevent rumen acidosis. Initially the creep feed should be diluted with a digestible fibre source such as sugar beet pulp or soya hulls, which can gradually be reduced.

Starting with a high protein content (around 18%) will also reduce the risk of acidosis. Cereals should be lightly processed – the grain should be just cracked open – otherwise, the rate of fermentation in the rumen will be very high and the microbes will produce an excess of acids, if finely ground.

Examples of mixes:

1. 1/3 wheat/maize dark grains, 1/3 barley, 1/3 sugar beet pulp with minerals – gradually reducing the sugar beet pulp over time.

2. Or a mix of 60% barley, 25% sugar beet pulp, 15% soya and mineral supplement (normally a bag to a tonne - 25kg).

A good quality protein source, such as soya bean meal is particularly useful as it is a source of undegradable protein. This will assist the transition to a weaned diet until there is enough microbial protein produced by the developed rumen. If you are using a proprietary feed, choose one with good quality palatable ingredients. If calves are introduced to creep early, some producers have been successful in using high levels of cereals as calves are accustomed to it, however if it is introduced later then not too much starchy feeds should be used to start with. The creep feeders should be kept topped up to avoid the calves overeating in one session, which is likely to occur if the feeders have become empty.

To maximise intake feed must be clean and fresh, so check the trough every day and clean it out if necessary to prevent bridging. It is also essential that calves can get good access to clean water.

This article has been funded by the Farm Advisory Service.