Focusing on the birth-to-weaning period for successful calf rearing

Heifer rearing represents the second-highest cost on dairy farms after feed, with costs amounting up to 20% of total milk production costs.calf

It is now widely accepted that calving at 22-24 months reduces rearing costs, results in greater lifetime performance and reduced metabolic issues at calving. Given this, it should be your goal.

The challenge is how to reliably achieve this and the period from birth to weaning is seen as critical in a heifer’s development.

Pre-weaning management – growth rates are essential

The target is for calves to double their birth weight by weaning at eight-to-10 weeks. For a 45kg calf at birth, this requires a growth of 0.8kg/day to reach a weaning weight of 90kg after eight weeks.

Farmers should adopt a policy of weighing calves at birth and, periodically, during the pre-weaning period. This is necessary so they can measure their calves’ performance.

Investing in a weighing crate or tape and getting into the habit of regularly monitoring calves will be money well spent.


Colostrum – quality, quantity and quickly

Probably the most important part of calf management is getting quality colostrum into calves quickly and at the correct quantity.

Key steps for colostrum management:
  • Test colostrum before feeding through the use of a Brix Refractometer;
  • Do not pool colostrum;
  • Feed colostrum with more than 50g/L of IgG (immunoglobulin G) at a rate of 10% of the calf’s bodyweight within four hours of birth;
  • This is necessary to achieve a minimum of 10g/L of IgG in the calf’s plasma by 24 hours after birth;
  • Typical feed rates are 4-5L/calf, but this will depend on IgG content;
  • Feed colostrum as soon as possible after birth, as IgG absorption rates reduce by 60% within six hours post birth;
  • Don’t let calves suckle their mother, as there is no way of knowing the quality or quantity of colostrum consumed. There is also a risk of contamination from dirty teats;
  • Feed colostrum from the calf’s own dam if the quality is good enough and the disease status of the cow is OK;
  • Good hygiene should be followed when managing colostrum to avoid pathogenic infection;
  • Colostrum should not be left in buckets around dairies or calf sheds for extended periods of time, as this heightens the risk of contamination.

Milk replacer

It’s important to promote high rates of daily gain with milk replacer early in life. But, it’s important that you do not overfeed calves. This can reduce or delay stater feed intakes, which are vital for rumen development.

Current recommendations are to feed 6L of milk per calf per day, containing 125-150g of milk powder per litre. Given this, a 45kg calf requires approximately 380g of milk replacer (3L fed at 125g/L) for maintenance alone, with any additional milk intake being utilised for growth.

As an easy rule of thumb, provide 1.5% of the calf’s bodyweight as solids during the first week of life. This increases to 2% of bodyweight from the second week of life until the week before weaning, when one feed is dropped.

Starter feed intake and chopped forages

It’s vital to promote the early intake of starter feed to physically and microbially develop the rumen, so that the animal can start to digest fibre as soon as possible.

Promoting high rates of starter feed intake is essential to produce volatile fatty acids (VFAs), which are the result of rumen fermentation of carbohydrates.

These VFAs, and specifically propionic and butyric acid, are vital for the development of the rumen papillae, which are essential for nutrient absorption from the rumen.

Fresh starter feed should be fed daily and farmers should target 300g/day of starter feed intake by three weeks-of-age. This feed should contain a high percentage of starch from cereals, high-quality protein and low-digestible fibre.


In addition, current recommendations are to feed a source of forage as 4% of the total solids feed intake. This should be chopped to 2.5cm and contain >65% NDF (neutral detergent fibre), as this promotes muscular development of the rumen and, thereby, facilitates higher intakes of starter feed.

A source of chopped forage will also aid rumination, which will contribute to rising rumen pH above 6 and it also acts like a tooth pick for the developing rumen papillae.

The weaning process should start when the calf is approximately 45 days old. It should involve gradually reducing the volume of milk fed daily, which should promote increased intake of starter feed.

A typical recommendation is to wean Holstein calves once they are consuming 2kg/head/day of starter feed for three consecutive days.

Benefits of Actisaf

Including Actisaf Sc47 protected live yeast in the ration provides significant benefits to calves during the pre-weaning stage.

Through its mode of action, Actisaf reduces trace levels of oxygen in the rumen and creates an environment where the main cellulolytic bacteria will grow and thrive. This improves fibre digestion when it’s already challenged by low rumen pH and enhances the development of the core ruminal microbiome.

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Actisaf also eases the transition on to starter feed, as it conditions the rumen microbes for the change in diet by biologically buffering the rumen and promoting a higher rumen pH through the stimulation of lactic acid utilising bacteria.

These bacteria reduce the build up of lactic acid in the calf’s rumen, which reduces the incidence of digestive upsets, such as acidosis. Acidosis can greatly impact on feed digestion, rumen development and calf growth rates.


Feeding Safmannan, which is a premium yeast fraction, can prove beneficial to calves and is particularly pertinent with the increasing focus surrounding antibiotic usage and subsequent resistance in calves.

Bouts of calf diarrhoea and respiratory disease, such as pneumonia, in the first three months of life have been shown to reduce heifer growth rates and to be detrimental to first and subsequent lactation yield of heifers when they enter the milking herd.

Therefore, management and nutrition of the calf – early on in life – has long-term implications. Furthermore, performance in the first three months of life can have a major bearing on first lactation performance of the heifer in the milking herd.

Safmannan is manufactured from unique strains of yeast under extremely consistent manufacturing conditions.

Beta glucans and mannans – the functional properties of Safmannan – help support the immune status of calves and support the defence mechanism to on-farm challenges.

Safmannan can bind to pathogenic bacteria, which can result in reduced pathogen pressure for the young, vulnerable animal.

More information

For more information on Actisaf and Safmannan contact Phileo Lesaffre at: 061-708099. Click here for more information