Basics of good calf rearing

Calf Rearing – 5 steps to optimising growth in calves

Growing a healthy animal that produces high yields should be the goal of every calf rearer. Their growth in the first 6-8 weeks (pre-weaning) plays a big role in shaping their potential.

In a dairy heifer for example, this is the phase that determines development of the udder cells, which are in turn responsible for milk production. So, strong early growth points to higher lifetime production.

Here are five simple steps that will help you to optimise growth in your calves pre-weaning:

1. Feed colostrum

The most valuable nutrient for the newborn calf, colostrum contains high energy levels, growth promoters, vitamins and immunoglobulin, vital for protection against disease. Timing is also critical for the viability and health of the calf – colostrum must be fed within six hours of birth. Any later and the colostrum can no longer be absorbed into the blood stream, reducing the immunity of the calf.

Volume of colostrum feeding

2. Invest in a quality milk replacer

Today’s calves are tomorrow’s producers – don’t skimp on calf milk replacer (CMR) because cheap is not necessarily good. There are essential differences in digestibility (making use of nutrients), solubility, intake, and consistency of quality when it comes to different milk replacers. These differences have a major impact on the health and growth of young calves.

Consider whey-based CMR

The majority of the world’s calves are reared on whey powders, like Sprayfo because these formulas are easily digested in the gut, moving through the calf in only 2-3 hours, compared to 5-8 hours for traditional curding (casein) formulas.

Find out more about why whey-based milk replacers are better for young animals, click here >>

3. Encourage early rumen development

The rumen is small at birth. Your aim is to convert a calf from purely milk fed to functional ruminant as quickly as possible. The early milk feeding period is the most vulnerable period for the calf from both a nutritional and disease challenge point of view.

Note that milk causes no rumen development at all, as it by-passes the rumen and goes straight to the abomasum. So, you want to encourage the calf to consume alternatives to milk, like grain and water as soon as possible.

Calf milk feed flow

Calf feed flow table

To optimise rumen development and accelerate growth rates to achieve early weaning, calves need to have a palatable grain based ration and ad-lib water on offer as soon as possible. This is where a good quality whey CMR compliments the ideal feeding system for young calves – because it’s quickly digested, the animals will seek out more sustenance.

calves pre-weaning feeding system

Calves fed on milk and grass only will eventually develop a functional rumen but the process will take much longer.

Calf rumen development

5 requirements for healthy rumen development

  1. Establishment of bacteria
  2. Liquid (free water not milk)
  3. Outflow of material (muscular action)
  4. Absorptive ability of tissues
  5. Substrates to allow bacterial growth

The importance of water

Water is an essential and often overlooked nutrient in the development of young animals.

Water intake from milk is not enough to meet a young animal’s needs; drinking water is imperative for good rumen development and will improve feed intake and weight gain.

  1. Provide ad-lib access to water always.
  2. Make sure the water is clean and a reasonable temperature.

4. Promote a healthy gut

Ruminant animal digestion relies on gut enzymes and thousands of specific micro-organisms in the digestive tract to break down feed to provide energy for skeletal growth (protein) and mineral nutrition.

However, rumen micro-organism populations can be influenced by the type and quality of milk replacer and other factors like stress (caused by birth, housing, feed change, weather or transport).

A healthy rumen from the start will lead to better growth and vigour in a young animal, maximising production in the long term. We can enhance gut health by feeding the following supplements:

Probiotics and Prebiotics

Probiotics promote gut health by flooding the gut with useful bacteria, so preventing harmful bacteria from colonising the bowel. Prebiotics on the other hand are large polysaccharide that are indigestible to the host but are a good nutrient source to the bacteria already present in the gut, thus enabling these useful bacteria to survive and multiply. Products on the market include Biopect, yoghurts, Biostart, ProCalf and Yeastsac.

Sodium Bentonite

A clay that modifies gut motility and absorbs excess fluids and microbial toxins. Products in this group include Trubond and Rumenite.

Vitamins and Minerals

Colostrum is high in vitamins and minerals. The addition of extra vitamins and minerals after the colostrum period may increase gut health.


There is never a time when antibiotics should be added to milk to prevent disease.

5. Housing should be dry and draft-free

There should be enough barn space to be able to house at least 50% of calves born on farm. Best practice is to have multiple barns, so that young calves can be isolated from older or sick calves.

  • Barns should be open on one side and divided into group pens, holding no more than 20 calves (10 is ideal).
  • Calves should be placed in their allocated pens and stay there for the entire indoor rearing period.
  • Each calf should be placed in a clean group pen that has not been previously used by other calves.
  • Calf barns should be located well away from the cow shed and feeding pads (to prevent the spread of disease)
  • Disinfect the barn, feeding utensils and trailer with a good quality, safe virucidal product (see Halamid) twice a week
  • Control rodents, birds and dogs
  • Bedding should be soft (shavings, straw) and at least 100mm deep – replace daily or disinfect (see Stalosan F – a powerful drying agent which remains active for several days)

Focusing on these five key areas should enable good growth rates and the development of healthy calves. For more information or to have the AgriVantage team visit you on farm, please get in touch.