“Today’s calf is tomorrow’s cow”
1. Calf feeding
1. Aim of calf feeding
The aim of calf feeding should be to reduce the mortality (death) rate while maintaining a growth rate of at least 400 g/day. For bigger breeds (Friesian and Ayrshire) the aim should be to wean calves at 12 weeks at approximately 80 kg body weight.
The primary concern in rearing the newborn calf is to ensure it remains healthy. Feeding management addresses nutrient requirements and in the initial stages should be primarily directed at encouraging rumen development.
2. Stages of development of the calf rumen
Calf feeding is divided into four phases, depending on the development stage of the digestive system.
When the calf is born, the rumen is not functional and forms only a small proportion of the stomach. As such the calf cannot digest complex fibrous feeds. The calf is thus fed on liquid feeds and low-fibre solid feeds until the rumen develops. As these feeds are mostly milk or milk by-products, which are expensive, early rumen development to allow feeding of cheap feeds is desirable. Early development is stimulated by feeding solid feeds. Concentrate feeding has been shown to stimulate development faster than fibrous feeds.
Colostrum phase (1–3 days)
The calf is born with low immunity (protection from pathogens found in the environment) and is therefore susceptible to infections. Colostrum is the first milk extracted from the mammary gland of the cow after calving. Colostrum is a source of antibodies that protect the calf from these pathogens. It is therefore imperative for calves to get this milk immediately after birth as the rate of absorption is highest within the first 3 days.
Pre-ruminant phase (4 days to 20–30 days)
During the pre-ruminant phase, the calf rumen is still not functional and the calf can only take in liquids. The calf cannot digest complex carbohydrates or complex protein and thus only milk or milk by-products should be fed. Milk replacers should contain simple proteins. Rumen development starts towards end of this phase.
Transition phase (2 to 3 weeks before weaning)
Rumen development continues. In addition to liquids, the calf should be encouraged to consume dry feeds, especially concentrates, as they are known to accelerate rumen development.
Post-weaning phase
In the post-weaning stage, the rumen is fully functional and the calf can handle fibrous material. However, the calves should be weaned on high-quality pasture and fodder to maintain a high growth rate. Water should be made available ad libitum.
3. Calf feeds
Colostrum
Colostrum provides both antibodies and nutrients to the calf. Antibodies protect the calf against diseases the mother has been exposed to and their absorption in the digestive tract occurs for an extremely limited period (significantly reduced 12 hours after birth and very low after 24 hours).
If necessary, help the calf consume colostrum from a nipple bottle. If new animals are introduced into the herd just before calving, it may be necessary to vaccinate them against the common diseases so that they can develop antibodies. If for any reason the calf is not able to get colostrum from the mother, make artificial colostrum (see below), use stored (frozen) colostrum or use a contemporary mother.
Where possible, the calf should be allowed to suckle for at least 3 days before separating it from the mother. A supply of high-quality colostrum should be saved and frozen for use by calves from cows that die at birth or have mastitis or milk fever.
Preserved colostrum
Exotic breeds produce colostrum in excess of the calf’s requirement. As colostrum has a high nutrient content, do not discard this excess but store it for feeding the calf later.
The colostrum can be preserved by several methods. Freezing is ideal but is not feasible on small-scale farms without electricity. Other methods include natural fermentation (store at room temperature) and use of preservatives (formaldehyde 0.05%, or formic acid 0.1%).
Before feeding the calf, mix the colostrum with warm water at the ratio of 2 parts colostrum to 1 part water.
Artificial colostrum
If the mother does not produce colostrum, artificial colostrum is recommended. Artificial colostrum does not provide antibodies but is rich in nutrients.
The recommended composition of artificial colostrum is
1 egg (beaten) + 400 ml fresh warm water + 600 ml whole milk + 1 teaspoonful castor oil or cod liver oil.
Feed this mixture 3 times a day for the first 3 days of life. A calf that has not received any maternal colostrum requires much more care.
Milk
Since milk is the saleable product from a dairy farm, it is necessary to switch young calves to cheaper feeds as early as possible. However, the diet must be able to promote health and growth.
Calves should be fed milk at the rate of approximately 10% of their body weight (reducing this as the calf starts to consume other feeds) to achieve good growth rates. Feed at body temperature. The milk can be mixed with other milk products (whey or skim milk) to lower cost. Whey (powder or liquid) can be obtained from creameries making cheese and skim milk (powder or liquid) from butter makers.
Milk replacer
Before using saleable milk or milk replacer, make proper use of stored excess colostrum. Use milk replacer only if it has an economic advantage over milk. Compare on the basis of dry matter. For example, Friesian milk contains about 26% protein and 30% fat on a dry-matter basis while most milk replacers contain about 23% protein and 15% fat.
Calf starter
The starter contains a slightly higher fibre content than does the pre-starter, a highly digestible, highly palatable feed specifically formulated as the first dry feed to allow early intake. At this stage the calf is consuming little milk and its rumen is still not fully developed. The starter should contain 18% crude protein, low fibre, 0.7% calcium, 0.45% phosphorus and vitamins A, D and E.
Roughage
Offer calves only high-quality forages early in life and supplement with concentrates (calf starter). If hay is used, it should be of high quality, fine texture, mixed with legumes and fed ad libitum. If calves are on pasture, it is best to always graze them ahead of adults
to avoid calves consuming parasite eggs or larvae that are normally shed through the faeces of adult animals onto pastures.
Common roughages offered to calves include sweet potato vines and freshly harvested, wilted lucerne.
Water
Calves should be offered fresh water in addition to milk. Lack of drinking water slows down the fermentation process of the starter in the developing rumen, which in turn slows down development of the rumen lining and it takes longer before calves can be safely weaned.
It is estimated that efficient conversion of feed into body mass growth requires about 4 kg of water for each kilogram of dry feed calves eat. Lack of water thus lowers feed conversion. Age and stage of development determine how much water calves require:
- From 1 to 6 days of age, calves may drink large quantities of water when it is first presented. This novelty water consumption pattern rarely persists more than a day or two as long as water is offered ad libitum.
- Calves less than 3 weeks old do not need a lot of water but a steady supply of clean, fresh water is recommended.
Between 3 weeks and weaning, calves’ water consumption usually increases and water should be offered ad libitum.
2. Calf feeding methods
1. Individual suckling
The natural way for a calf to feed is to suckle the dam after she is milked, the farmer having made sure that the dam is not milked dry. This is the most hygienic way as the calf gets milk direct from mother, clean and at body temperature.
2. Foster mother or multiple suckling
One milking cow may be assigned a number of calves to suckle, depending on the level of milk production. This is practical only on farms with several cows lactating at the same time.
3. Nipple suckling
A rubber nipple is fixed on a milk bottle and the calf is trained on how to suckle. The alternative is to put milk into a bucket and insert a flexible plastic hose pipe with one end attached to a nipple.
4. Bucket feeding
The most commonly used method is bucket feeding. The calf is trained to drink milk placed in a bucket (place your finger in the milk and as calf suckles your finger it imbibes
milk). Stainless steel buckets, where available, should be used for hygienic reasons as plastic buckets are difficult to clean. At all times, feed milk at body temperature. This is especially important during the cold season.
Sick calves should always be fed last to minimize cross-infection.
3. Nutritional disorders
A calf’s health can be affected by disorders resulting from improper feeding. Diligent feeding management is therefore essential to ensure calf health is maintained. Common problems associated with feeding are diarrhoea and pneumonia.
1. Scours (diarrhoea)
Scours may be caused by nutritional disorders, viruses or bacteria. Digestive upsets leading to scours are a major cause of mortality in young calves.
The problem can however be minimized by
- ensuring calves receive adequate colostrum within 6 hours of birth and therefore acquire some natural immunity
- feeding the correct amount of milk
- recognizing, segregating and treating scouring calves early
- maintaining hygiene and cleanliness of feeding utensils and the environment
- not rearing calves continually in pens, dirty yards or small paddocks that become heavily contaminated; paddock rotation will help prevent disease
- separating sick animals to avoid cross-infection
Closely observing calves at feeding to identify scouring animals as soon as possible for remedial treatment will prevent dehydration and secondary disease leading to chronic illness and mortality.
Incidents of scours can be treated simply by using electrolyte replacers fed several times per day to prevent dehydration. Reduce or omit milk for one or two feeds but provide fresh water, concentrates and forage. Do not use antibiotics to treat scours resulting from overfeeding or digestive upsets.
Blood scours (mostly caused by coccidia) require veterinary treatment and management changes to improve hygiene.
2. Pneumonia
One cause of pneumonia in young calves is fluid going to the lungs via the windpipe (trachea). The first feeding of colostrum can cause problems if the feeding rate is faster than the swallowing rate.
If colostrum is bottle fed it is important to use a nipple that matches the calf’s ability to swallow. Greedy calves swallow large quantities of milk from the bucket, some of which may end up in the windpipe, leading to pneumonia.
4. Calf feeding program
The calf feeding program shown inTable 6.1 should result in a growth rate of approximately 400–500 g/day. The liquid feed (milk) should be fed twice daily and more frequently for sick or weak calves.
Table 6.1. Example of a calf feeding schedule with weaning at 12 weeks
| Age of calf (days) | Milk (kg/day) | Total cumulative milk (kg) | Calf starter (kg/day) |
| 1 to 7 | colostrum | — | — |
| 8 to 21 | 5 | 70 | handful |
| 22 to 42 | 6 | 126 | 0.5 |
| 43 to 56 | 5 | 70 | 0.5 |
| 57 to 63 | 4 | 28 | 1.0 |
| 64 to 77 | 3 | 42 | 1.0 |
| 78 to 84 | 2 | 14 | 1.5 |
| Total | 350 | 4.5 |
Calves should be given roughage throughout.
5. Weaning
Weaning is the withdrawal of milk or milk replacer while the calf becomes fully dependent on other feeds. Traditionally, dairy calves are weaned based on age, 12 weeks being the most common. Early weaning is possible if more milk is fed and calves are introduced to pre-starter and starter early in life.
To minimize stress, wean gradually. Reduce the milk feeding from twice a day to once a day then to once every other day to allow the calf’s digestive system to adjust to the new diet.
Criteria that have been used to determine weaning time include when the calf attains twice its birth weight, when the calf can consume 1.5% of its body weight of dry feed and the age of the calf.
6. Bull calves
Of the calves born, about 50% will be bull calves, which consume milk and compete with heifers. Farms dispose of the bull calves in different ways, depending on the economics and type of production. These include
- selling after birth
- slaughtering after birth
- rearing as beef steers
- rearing as possible future sires
Base the decision to keep or dispose of bull calves mainly on the cost of rearing them— price of milk vs disposal price—and the genetic value for future sires.