Disease issues with feeding whole milk

The first thing for farmers to remember when feeding un-pasteurised whole milk is the disease implications. Johne’s disease is one that can be spread through feeding calves un-pasteurised milk to calves from an infected cow.

Where the disease is a problem in a herd, pasteurising the milk or feeding milk replacer should be explored as methods of halting the spread of the disease inside the farm gate. Feeding milk from cows with high cell count or cows that have been fed antibiotics should be avoided also.

Level of whole milk feeding

Traditionally calves are fed approximately 4L of milk per day (2L in the morning and 2L in the evening). This just barely covers the nutritional requirements of the growing calf. Feeding calves 6L (3L in the morning and 3L in the evening) for the first three weeks of life will increase the rate of growth at a young age resulting in a stronger calf thereafter.

After three weeks of age the calf will be able to consume larger levels of concentrates. Lowering the milk feeding level to 4L per day after this should increase concentrate intake.

Feeding ad-lib whole milk

Several farmers are considering feeding milk ad-lib to calves. This can be done, but there is an increased risk of dietary upsets and a longer more gradual weaning onto concentrates is required. If a calf is consuming ad-lib whole milk, the amount of concentrates being consumed will be low. In addition bringing the calf up onto concentrates will be a slow process.

Research from AFBI (Agri-food and Biotechnology Institute) in Northern Ireland suggests that calves should be consuming about 1kg of concentrates per day before weaning in order to reduce the impact of weaning.

Calves being fed whole milk ad-lib should continue on the milk diet and gradual weaning should not commence until the calf is about 12 weeks of age. Farmers buying calves that have been fed ad-lib milk should ensure that the calves are consuming concentrates at purchase, even if aged, calves on ad-lib whole milk eating low levels of concentrates need to have milk feed reduced gradually while allowing concentrate intake to increase and the rumen to develop.

Milk acidifiers

Increasing the intake of milk to ad-lib levels can be tricky. Fluctuations in milk temperature can impact on intake greatly leading to digestive upsets and dietary scours. In addition there is the possibility that pathogen levels may build in the milk or feeding equipment during the day.

Milk acidifiers can be used effectively for ad-lib feeding. By reducing the pH of the milk, this ensures that pathogens will not be able to grow, thus creating a more stable product. The addition of milk acidifiers can lead to reduced levels of bacterial scours and can promote increased intake and utilisation of milk.

Milk replacer

Milk replacers are often used by both dairy and beef farmers rearing dairy calves. By using milk replacer the farmer can ensure the consistency of the feed. There are several different types of milk replacer on the market and they can vary in quality.

When choosing a milk replacer, the quality of the contents is essential. The protein source can vary between products; a whey based protein source can be advantageous. It is a low cost constituent, a by product of the cheese making industry.

In addition a whey based protein source is in a form that is easily digested by the calf. Milk replacers can have a protein level of 22-27%. Higher protein milk replacers are generally fed to calves that farmers want to maximise development, such as replacement heifers.

In order to supply additional nutrients to young calves over the requirement for maintenance and growth, protein levels of 25% should be fed. When changing calves onto milk replacer or between types of milk replacer, this should be done gradually over a period of 3-4 days to avoid digestive upsets.

Hygiene

Whether feeding whole milk or mixing milk replacer, hygiene is critical. Milk is an ideal breeding ground for bacteria and pathogens. If fresh milk is not being fed twice per day, it should be refrigerated to slow or halt the rate of growth of pathogens.

In addition, feeding equipment should be cleaned after each feed and where the same feeder is being used for several batches of calves, washing with hot water can limit the spread of disease between feeders substantially.

Acidified milk will keep stable at room temperature for up to 2 days. The lower pH reduces the possibility of bacterial growth leaving it more useful in an ad-lib situation where milk is available to calves all day.

Key points

· Use only saleable milk to feed calves

· Disease such as Johne’s can be spread to calves by feeding infected milk

· Higher milk feeding levels in the first 3 weeks can increase growth rate and provide additional nutrients to cope with sickness

· Milk acidifiers are useful when feeding ad-lib

· When a calf is fed ad-lib weaning should be deferred until 12 weeks of age

· Calves should be weaned gradually when consuming 1kg of concentrates

· The quality of milk replacers can vary – pay attention to the protein type and level

· When changing from milk to milk replacer or changing milk replacer type, do so gradually

· Refrigerate whole milk if not feeding in 1-2hrs

· Clean feeding equipment with hot water between batches of calves