Rearing Calves

Calf Rearing Guide

Practical calf rearingBack to top
The Veanavite® calf rearing system was originally developed by Tom Grant, in conjunction with researchers at Sydney University. Refined to include all aspects of successful calf rearing, from nutrition and housing to health and management, the Veanavite® rearing system is designed to enhance natural rumen development, whilst ensuring the healthy growth of the calf.

Golden rules for rearing healthy calves
  • Select and rear good quality calves
  • Provide adequate colostrum within 6 to 8 hours of birth
  • Take preventative action for navel and respiratory infections
  • Introduced calves should be given Veanalyte Electroguard on arrival
  • House calves in clean, dry, well ventilated draught-free housing with 1.5 square metres of space per calf
  • Feed Veanavite® Calf Milk Replacers once or twice a day and follow mixing and feeding instructions
  • Provide good clean straw and clean water at all times in close proximity to milk and pellet feeders
  • Allow unrestricted access to Veanavite® No 1 Calf Pellets from day 1 of the feeding program
  • Calves can be weaned off milk when consuming a minimum of 750 g to 1 kg of pellets per head per day
  • House calves off pasture until 10 to 12 weeks of age
  • Feed Veanavite® No 2 Calf Pellets to supplement the pasture phase and maintain growth rates to joining
  • Maintain good preventative health management and respond quickly to any problems that occur
  • Ensure facility is completely cleaned out and spray pens with anti-viral anti-bacterial spray between batches of calves
ColostrumBack to top
Correct colostrum management is fundamental to any calf rearing program. Colostrum is the first milk from the cow containing high concentrations of antibodies (immunoglobulins), protein, energy, minerals and other essential nutrients for calf survival and future health and well-being. Antibodies are complex proteins designed to combat infection.

The newborn calf has little active immunity against disease and must absorb antibodies from the colostrum through the wall of the intestine to gain protection. The calf's ability to absorb antibodies from colostrum is highest at birth and declines in the following 24 hours. Ideally, calves should receive 2 litres of good quality colostrum within one hour of birth, and a further 2 litres within the following 12 hours.

Some practical measures can be employed to ensure the intake of colostrum at the correct time is optimized. Feeding cows an appropriate transition diet containing anionic salts 14 days prior to calving ensures calves are born quickly and can access colostrum before their ability to absorb antibodies declines. A measured dose of colostrum should then either be suckled by the calf or alternatively delivered directly by stomach tube.

Colostrum quality varies with age, breed and health status of the dam and can be tested for the level of antibodies with a colostrum tester. High quality colostrum can be frozen in plastic bags or containers. It should be thawed by placing in a bucket of warm water. Do not use a microwave oven.
Navel disinfectionBack to top
The navel of a newborn calf is the simplest and most likely site for direct infection to enter the calf. To prevent navel infections, ensure the navel is clean and dry by treating the navel with a 5% iodine solution as soon as possible after birth. Always calve on clean dry ground and rotate calving paddocks.

Problems that may arise from navel infection include:
  • Joint ill – swollen front knees being the most common;
  • Blood poisoning (septicaemia) resulting in sudden death in the first week; and
  • Local infections of the navel.
For infections of this nature, consult your veterinarian.
VentilationBack to top
The immune system of the calf is not fully functional until about 12 weeks of age. The calf is very susceptible to infections from airborne pathogens and lung damage from ammonia in the atmosphere. Calves can harbour sub-clinical infections that develop into pneumonia when the calves are subjected to environmental stresses.

The most common circumstance leading to lung infections is poor ventilation. Poor ventilation causes an increase in the humidity and temperature inside the housing and creates the perfect environment for bacteria and viruses to thrive. The build-up of gases such as ammonia under conditions of poor ventilation damages the lungs and makes them more susceptible to infection. In addition, high pressure hosing near calves should be avoided as the mist given off contains bacteria from manure which are inhaled by the calves.

Lung infections can be minimised by ensuring calf housing has adequate, draught-free ventilation. Calf housing should have flow-through ventilation, starting above calf height to avoid draughts. Awnings should be used on the side of the prevailing weather to prevent rain entering but still allow ample air flow.
Scour prevention and treatmentBack to top
Scours accounts for more than 60% of all calf deaths, therefore vigilance and rapid treatment of scours is essential. Scours is the general term used to describe a variety of conditions in calves, characterised by a major loss of water and nutrients in the faeces, resulting in rapid dehydration and often death.

Most scours are caused by environmental stresses such as transportation, overfeeding, feeding changes or feeding poor quality products. These stresses can lead to outbreaks of infectious scours caused by agents such as bacteria (E. coli, Salmonella), viruses (Rotavirus) or protozoa (Coccidia). Adequate colostrum intake gives calves a first line of defence against scours.

Non-infectious or nutritional scours are due to digestive imbalances which disrupt the natural processes of digestion. Digestive imbalances cause physical discomfort and upset the osmotic balance of the calf. In addition, the pH of the intestines may change from optimal conditions, further increasing the risk of bacterial infections.

Understanding the process of milk digestion in the calf has enabled the development of feeding programs and products to reduce calf scours. When a calf drinks milk, the milk bypasses the first three stomachs to enter the fourth stomach or abomasum. Rennet causes the milk casein to clot within the acidic environment of the abomasum which is unfavourable to harmful bacteria. The casein in Veanavite® Milk Replacers clots readily to assist this process.

The acid condition of the upper intestine further prevents harmful bacteria from invading the small intestine and causing infections. Under ideal conditions, the digested material passes slowly through the small intestine where the majority of digestion and absorption takes place.
Infectious scoursBack to top
Calves with infectious scours often appear dull, listless and off their feed. These calves require Veterinary treatment for the infection as well as Veanavite® Electroguard electrolyte therapy to restore the balance of salts in the body. Veanavite® Electroguard is mixed with clean, warm water and administered according to the packaging instructions to restore the calf's osmotic balance until the calf is feeding normally again.

Always consult your veterinarian in these cases to identify the type of infection and to obtain the appropriate treatment for the infection.
Nutritional scoursBack to top
To treat nutritional scours, supplement with Veanavite® Electroguard, which contains a blend of electrolytes and carbohydrates critical to maintaining the osmotic balance of the calf.

Veanavite® Electroguard also contains a gel forming agent which coats the lining of the intestine, improving mineral and carbohydrate absorption, slowing the passage of the digested material and helping to minimise the risk and severity of scours.
Coccidiosis preventionBack to top
Coccidiosis is caused by a protozoan – not a bacteria or virus. It causes infection of the intestine starting as a white scour and turning to a blood scour as the lining of the intestine is damaged. Most soils contain coccidia and all calves are susceptible to coccidiosis until about 3 months of age when resistance develops. Heavy stocking rates and wet conditions are conducive to coccidiosis outbreaks. Once a calf has coccidiosis, it must be treated by your veterinarian.

Coccidiostats in calf pellets or meals will not control the pathogen until calves are consuming approximately 1 kg of pellets per day, typically 5–8 weeks of age. Until this time prevention must come via the milk ration.

Veanavite® Supacharge and Veanavite® Pro milk replacers have added Bovatec, a coccidiostat which can prevent and treat Coccidiosis. If using other milk replacers that do not contain a coccidiostat add 15g of Veanavite® Supastart per calf per day during the entire milk feeding phase to prevent coccidiosis.  Veanavite® Supastart also contains a vitamin and mineral premix to supply the calf with essential nutrients. These help the calf to withstand stress and build a healthy immune system.
Parasite controlBack to top
If calves are housed without access to pasture they will be relatively worm-free. Slats and deep litter (sawdust, rice hulls etc) are not conducive to worm egg survival and calves are not eating off the ground to pick up worm eggs.

Rearing calves in calf paddocks, particularly with year-round calving, creates severe worm problems. Worm burdens build up and calves have little resistance to them, often resulting in scours and severe growth checks.

Worm problems are unlikely to cause scouring in calves less than 6 weeks old; however drenches are very effective for treatment of worm infections in calves. Regular worm control is essential once calves have access to pasture.
VaccinationBack to top
All calves should be vaccinated against clostridial diseases and adults should be given an annual booster. It is essential that 2 doses of vaccine are given to calves: the first at about 6 to 8 weeks of age and the second 4 to 6 weeks later. If cows are vaccinated, passive immunity is passed on to calves which covers them for the first 6 to 8 weeks of life.

Replacement heifers for the dairy herd should also be vaccinated for Leptospirosis.
DisinfectionBack to top
To maintain a clean calf rearing environment, use a good quality disinfectant according to the manufacturer's instructions. The disinfectant should be effective against the many viruses and bacteria harmful to calves. The disinfectant offers protection against pathogens such as bacteria, viruses and fungi. Bedding conditioners can be sprinkled on clean floors or applied to the bedding to reduce the risk of infection and keep the bedding dry for animal comfort.
HousingBack to top
Calves have a natural preference to eat pasture or good quality hay, however consumption of these materials will severely restrict the speed of rumen development and may be harmful to the health and well being of the animal. When feeding for rumen development:
  • House the calf off pasture for the first 10 to 12 weeks to encourage pellet consumption;
  • Ensure calf housing is clean, warm, dry, well ventilated, draught free and well lit: decontaminate housing between batches of calves
  • House calves at 7 calves per pen maximum
  • Allow 1.5 square metres per calf for individual pens and group pens on deep litter (rice hulls, sawdust, wood shavings, straw etc) or 1.1 square metres per calf on timber slatted floors
Timber slatted floors should be made of 50 mm wide x 25 mm thick hardwood and should have a gap of 30 mm between slats. Mesh floors of any kind are not recommended as they are cold, hard, expensive and difficult to clean.
The importance of early rumen developmentBack to top
At birth, the rumen represents approximately 30 per cent of total stomach capacity and the abomasum 55 per cent in the calf. In the mature animal, rumen capacity is around 80 per cent, whilst the abomasum represents about 10 per cent. This reflects the natural development of the rumen as a result of the gradual change from a predominantly milk diet in the young calf to a solid diet in the mature animal (see diagram below, Moran, 1993, Victorian Department of Agriculture).

A developed and functional rumen can only be developed by a number of physical and chemical processes. A developed and functional rumen will have muscular tone, a population of appropriate bacteria, nutrient absorptive capacity and enough size to process adequate volumes of feed. The speed of rumen development is not controlled by the calf's age or weight but by the diet fed to the animal and the physical and chemical processes associated with its digestion. The process of rumen digestion converts feedstuffs into compounds that can be readily utilised and ultimately provide the energy and protein required by the animal. These compounds are absorbed directly from the rumen or are absorbed further down the digestive tract and are essential for the maintenance, growth and development of the calf.

Therefore, nutrition and general health of the calf will determine the rate of rumen development. There is a significant difference in the time taken to develop a functional rumen in a calf reared on a cow or fed a diet with unrestricted milk in comparison to a calf reared in an early weaning system, which includes pellets and straw and is designed to promote rapid rumen development.


Milk feeding programsBack to top
The milk feeding regime is vital to the Veanavite® calf rearing system. During the milk phase, the aim is to encourage pellet consumption by allowing unrestricted feeding of pellets from day 1. Calves can be fed milk at any time of day as long as the timing is consistent.

Veanavite® Calf Milk replacers are suitable for use in a variety of rearing situations. They can be fed once or twice a day, blended with water or used to fortify unsaleable milk or milk fed from the vat. They are equally suitable for use in calf auto feeder machines.
Once or twice a day feeding?Back to top
The decision to feed calves once or twice a day will depend on the type and number of calves, rearing facilities available and the required outcome.
Optimal healthBack to top
Good nutrition in early life is vital to maintaining a healthy immune system which plays an important role in developing immunity and resilience to diseases and ill health.
Economy once per day feeding programBack to top
Once a day milk feeding can produce calves with digestive systems that develop more rapidly, resulting in earlier weaning off milk and potential cost savings. In addition this type of program can reduce labour requirements. Once a day feeding is popular in many large rearing facilities for both dairy and beef crossbred calves.

First 4 – 6 weeks Once a day milk feeding with Veanavite® Calf Milk Replacers with access to Veanavite® No 1 Calf Pellets, straw and clean water.

Weaning Wean off milk when calves are regularly consuming 750 g – 1 kg of pellets per day (around 4 to 6 weeks of age) and continue to house off pasture whilst feeding pellets, straw and water.

Pasture phase (Commencing at 10 – 12 weeks) Introduce calves to pasture and supplement with Veanavite® No 2Calf Pellets and good quality fodder to maintain desired growth rates.

Benefits of early weaning Promotes earlier rumen development. Encourages pellet intake. Excellent growth rates. Minimal health problems. Can save time, labour and money. Simple and easy to follow.

Economy Early Weaning Program (Once Per Day Feeding)
* All figures are per calf.
Feeding weeks Day Number days Number Feeds per day Milk Powder per feed (grams) Water per feed (litres) Total Feed Volume per Feed (litres) Total milk powder/calf/ day (grams)
Week 1 Day 1 (colostrum) 1 2 NA NA NA NA
Week 1 Day 2-7 6 2 225 1.70 1.85 450
Week 2 Day 8-14 7 1 500 2.50 2.85 500
Week 3-6 Day 15-42 28 1 600 2.50 3.00 600
* If feeding beyond week 6 feed at same rates as per week 3,4,5,6
Calves consuming 750g – 1.0kg pellets per calf per day for 3 consecutive days can be safely weaned off milk.
Hi-growth twice per day feeding programBack to top
If you are trying to achieve maximum growth rates in your calves, a Hi-growth feeding program may be better suited. Improved early nutrition may stimulate optimum mammary development of dairy heifers, potentially having positive outcomes on long term milk production. A twice per day feeding program is ideal where accelerated growth rates are required.

Twice per day feeding is also used widely when rearing small numbers of calves in a hobby farm situation where labour is less of an issue.

Hi-Growth Feeding Program (Twice Per Day Feeding)
* All figures are per calf.
Feeding weeks Day Number days Number Feeds per day Milk Powder per feed (grams) Water per feed (litres) Total Feed Volume per Feed (litres) Total milk powder/calf/ day (grams)
Week 1 Day 1 (colostrum) 1 2 NA NA NA NA
Day 2-3 2 2 250 1.80 2.00 500
Day 4-7 4 2 300 2.00 2.30 600
Week 2 Day 8-14 7 2 350 2.30 2.60 700
Week 3 Day 15-21 7 2 400 2.70 3.10 800
Week 4 Day 22-28 7 2 450 3.00 3.40 900
Week 5-7 Day 29-49 21 2 500 3.00 3.50 1000
Weaning off milk
Week 8-9 Day 50-55 5 2 400 2.50 2.70 800
Day 56-60 5 2 300 2.00 2.30 600
Day 60-63 4 1 300 2.00 2.30 300
Calves consuming 1–1.5kg pellets per calf per day for 3 consecutive days can be safely weaned off milk.
Hi-growth calf rearingBack to top
To allow calves to achieve their genetic potential for growth, they must obtain enough nutrients for both maintenance and growth. This can be achieved through accelerated calf rearing programs. Accelerated calf rearing involves feeding greater quantities of higher protein calf milk replacers to achieve increased body weight gain. This approach focuses on early calf nutrition by providing enough energy and protein to support and allow for maximum growth and maintenance requirements.

In contrast, traditional calf rearing programs restrict the amount of milk replacer fed to encourage solid feed intake and allow for early weaning. Feeding calves limited milk replacer however does not provide enough nutrients to suvpport maximal growth.

There have been numerous studies conducted on accelerated calf rearing and the benefits of early calf nutrition. Potential benefits include:

Potential increased growth Calves fed on an accelerated feeding program are generally heavier, taller and longer built calves. Calves are particularly efficient in utilising protein for lean tissue gain and feeding additional protein can be used very efficiently for growth. Feeding a greater quantity of calf milk replacers also provides additional energy, vitamins and minerals which contribute to improved growth.

Recent data indicates that calves fed on an accelerated feeding program will maintain the increase in body weight at least to four months of age if fed a high protein calf starter.

Improved production potential There is continuing research on the long term effects of early nutrition on subsequent productivity. Research has suggested that heifer calves fed on an accelerated rearing program can be bred earlier or will calve earlier due to the increased early growth. While ongoing lactation data suggests that improved growth rates and early nutrition translates into greater milk production. It has also been shown that increasing energy and protein intake from 2 to 8 weeks of age increases the development rate of mammary tissue. Whether this increase would translate into greater milk production is currently not clear.
Fortifying with Veanavite® milk replacersBack to top
Dairy farmers with unsaleable milk can obtain all the advantages of once a day feeding (any time of day) by adding Veanavite® CalfMilk Replacers to unsaleable milk or milk fed from the vat. The benefits of this include increased nutrition without increasing the volume of liquid feed and the benefits of added vitamins, minerals and other beneficial additives supplied in the milk powder. Follow the recommendations in the table below.

FORTIFYING MILK WITH Veanavite® MILK REPLACER (Once per day feeding)
* All figures are per calf.
Feeding weeks Day Number days Number Feeds per day Milk Powder per feed (grams) Milk per feed (litres) Total Feed Volume per Feed (litres) Total milk powder/calf/ day (grams)
Week 1 Day 1 (colostrum) 1 2 NA NA NA NA
Day 2-3 2 2 90 1.20 1.30 180
Day 4-7 4 1 250 2.00 2.20 250
Week 2 Day 8-14 7 1 300 2.00 2.30 300
Week 3+ Day 15+ - 1 350 2.00 2.30 350
Feeding grain based pelletsBack to top
When milk is consumed by the young calf, it passes directly into the fourth or true stomach (abomasum) via a vessel called the oesophageal groove whilst the pellets and other dry feeds directly enter the rumen. Veanavite® No 1 pellets play a critical role in the development of the rumen and are formulated for this function. The consumption of dry feedstuffs, balanced for protein and energy, provides the right substrates to develop a microbial population. Importantly, Veanavite® pellets contain a blend of carbohydrates and high quality proteins that are readily fermentable, which is essential for the rumen microorganisms to function and multiply.

Pellets are fermented by rumen microbes into compounds called Volatile Fatty Acids (VFAs). Volatile Fatty Acids provide a primary source of energy to the calf and are absorbed through the rumen wall via small blood vessel-rich protrusions called papillae. It is the VFAs, or by-products of microbial fermentation, that provide the chemical stimulus for the development of the blood vessel-rich surface of the rumen. The microbes that ferment the feed are themselves digested and ultimately provide the calf with an ideal source of protein. In a healthy, developed rumen the microorganisms flow in a steady stream from the rumen and are eventually absorbed as a near-perfect balance of amino acids from the small intestine.

Thus, feeding pellets is an excellent way to start rumen development within a few days of birth.
StrawBack to top
Clean straw is an important ingredient to promote early rumen development in any early weaning program. Clean bright barley straw is preferred and should be placed in close proximity to other feed sources to ensure consumption to maintain a stable rumen environment.

Straw is essential particularly after weaning when pellet intake increases rapidly and the calf is at a higher risk of suffering from acidosis. Acidosis kills off rumen microbes and damages the rumen wall which results in decreased feed intake, digestibility and growth rate. Acute cases can rapidly result in death. It is important to maintain a regular eating pattern that promotes a stable and healthy rumen environment.

Chemical buffers, such as sodium bicarbonate, are added to pellets to reduce the risk of acidosis but straw is a vital ingredient to promote healthy rumen function. Straw provides little or no feed value but does provide long fibre which helps develop the rumen's size and muscular rhythm. The length of the straw and dwell time in the rumen promotes the cud-chewing reflex that in turn stimulates the flow of bicarbonate from saliva, the calf's natural buffer, into the rumen. Thus freely available straw is essential.

When both pellets and straw are fed unrestricted, a healthy calf, free of digestive problems, will naturally balance the intake of both to maintain the pH in the rumen. A calf will consume about 1 small bale of straw during its 10 to 12 week rearing period.
WaterBack to top
Clean fresh water is essential for life and rumen development. The rumen is a large fermentation vessel and will cease to function without an adequate supply of clean water. Water troughs should be cleaned out daily.

Small self-filling waterers holding approximately 2 litres with a push out plug are ideal and can water up to 20 calves easily.
Introduction to pastureBack to top
The calf may be introduced to pasture at 10 to 12 weeks. The ultimate aim of the Veanavite® rearing system is to produce a calf that can efficiently utilise pasture at an early age as practical. It is important to provide a transition period during this phase to ensure that no digestive disturbances occur. The calf will require supplementary feeding with Veanavite® No 1 calf pellets at 1 to 2 kg per day for 2 to 3 weeks minimum during the transition period to pasture. During this transition period, the population of grass-digesting bacteria in the rumen gradually increases.

Veanavite® No 2 Calf Pellets are formulated to supplement calves at pasture after the transition period. The ongoing performance of the calf will depend on the quality and quantity of pasture available. At this stage, rumen volume still limits pasture consumption so growth is maximised by feeding Veanavite® No 2 Calf Pellets to balance any nutrient shortages. Weight gain up to joining can be maximised by continued supplementation with Veanavite® No 2 CalfPellets or Veanavite® Heifer DeveloperPellets. Some additional roughage to provide dietary fibre may be required on lush pasture.
After weaning and before pastureBack to top
Calves should be weaned according to the rearing plan they are on (ie. Once a day or accelerated). Within two days of weaning, the calf's pellet consumption will rapidly increase and its growth rate will rise.

After weaning, calves should continue to be housed off pasture and fed unrestricted pellets, straw and water until 10 to 12 weeks of age. By 10 to 12 weeks, a calf will be consuming 3 to 4 kg of pellets and gaining over 1 kg per day. The rumen will now have a viable microbial population and have enough volume for the calf to make the transition to high quality pasture.