Immunity and nutrition vital to calf performance

Alltech's Jonathan Knox.
Alltech's Jonathan Knox.

At the busiest time of the year on dairy farms, calves are often the last animal to receive care.

The calves hitting the ground today will be the future of your herd in 2020.

Allocating sufficient time and resources to calf management now is a worthwhile and cost-effective investment in the long run.

If we have followed a good dry cow programme with quality nutrition, minerals and management, we should have a healthy calf and good-quality colostrum, with the cow back in production.

Regardless of your cow type or production system, getting the basics right is the key. Some of the main areas to focus on are:

q Colostrum

q Nutrition

q Rumen development

q Immunity

q Colostrum

Colostrum is the first source of nutrients that the calf receives. It contains vital immunoglobulins (antibodies) from its mother’s immunity to protect it against pathogens and disease. The calf’s ability to absorb these immunoglobulins into the blood is at its highest in the first hour, so it is important to get colostrum into the calf quickly. The absorption rate declines rapidly thereafter and completely ceases at 24 hours. The golden rule is to get at least three litres of colostrum into the calf within two hours of birth for the first feed (this is the “3-2-1” rule). A second feed should be given within eight hours before transitioning to milk or a milk replacer. The quality of colostrum can vary a lot between animals and is affected by:

Age. Older cows have better colostrum.

Dry period length. Cows that are less than 40 days dry have poor-quality colostrum.

Vaccinations. Cows vaccinated for IBR rotavirus, E. coli and Bovine Viral Diarrhoea (BVD) have higher immunoglobin content.

Breed. Jersey cows can have better colostrum.

Time. Colostrum quality decreases quickly post-calving. At birth, it is 14.5 percent antibodies, but it drops to 2.6 percent at 24 hours.


Feed efficiency, or the rate at which calves convert nutrients to weight gain, is best in the first few months of life. It declines thereafter, so this early efficiency needs to be capitalised on.

Aim to double the birth weight before weaning at 10 weeks. Afterward, a 40-kilogram calf will need to gain 0.6 kilograms per day. It is a challenge to achieve this performance; correct feeding strategies must be implemented. Correct nutrition is more important than the method used for milk feeding, and labour is often the deciding factor. Aim to feed 15 percent of the animal’s body weight. For a 40-kilogram calf, that amounts to six litres per day. When mixing milk powder, always remember that it is 125 grams of powder to prepare up to one litre and not 125 grams added to 1 litre of water.

Rumen development

For the calf to perform later in life, it needs to have a fully functioning rumen. Development of the rumen is brought about by the starch content of concentrate feeds. Eating calf concentrate as early as possible is necessary. The feed needs to be very palatable and dust-free. During the first two to three weeks of age, the calf consumes little concentrate feed and is reliant on milk or milk replacer for its nutrient requirements. The amount of forage a calf can digest is small. High-hay diets can cause calves to become pot-bellied, which can diminish concentrate intake. They should have access to some straw, or you can add eight to 10 percent in the calf concentrate mix. This will strengthen the rumen wall. Water should be available to calves, separate from milk, at all times.


The biggest challenges from birth to weaning are scours and respiratory infections. By building the immune system from birth, we protect the calf and optimise its growth potential. Including Actigen, a yeast-based product from Alltech in your calf feed will help boost its immune system.

This improves gut function and nutrient absorption. Actigen enhances gut health by building natural antibodies. It’s proven to enhance feed efficiency, contributes to immunity development and improves calf growth rates.

In summary, along with management and environment, the main areas to focus on this calving season are:

q Colostrum: Quality and quantity.

q Nutrition: Know your weight gain and milk allocation.

q Rumen development: Use concentrate and correct fibre to build a robust rumen.

q Immunity: Give it a helping hand with management, environment and nutrition.