The calf is the foundation of the future dairy herd which signifies the importance of proper calf rearing. Selection of replacements for culled cows can only be effective if good replacement heifers are available and in enough numbers to allow for a more rigid selection. A good feeding and management programme will result in lower death rate (mortality), replacement heifers that start production early and fast growth resulting in rapid genetic improvement.
Management before birth
As calf management begins before birth, a few days before the calf is born, the pregnant cow is transferred to a maternity paddock, which should be near the homestead (for closer observation), well watered and free from physical objects. The signs of imminent parturition (calving) include filling of udder with milk and is turgid, vulva swollen with a string of mucus hanging from vagina. Insemination records can also be used to estimate the expected calving date.
Management at calving
After the calf is born, ensure that calf is breathing. Should breathing not commence, the calf should be assisted (remove mucus from nostrils and if breathing does not start hold calf by hind legs upside down and swing several times). The umbilical cord should be disinfected using disinfectant (iodine or copper sulphate solution). If the calf is unable to suckle, it should be assisted and be allowed to suckle colostrum from the dam at will during the first week. Any excess colostrum should be milked and stored or fed fresh to other calves. During the second week of life and thereafter, the calf should be separated from dam and fed by hand.
Feeding of the calf
The primary concern in rearing the newborn calf is to ensure it remains healthy. Feeding management should also be directed at addressing nutrient requirements and encouraging rumen development.
While designing a calf feeding program, the aim should be to reduce mortality (death) rate while maintaining a growth rate of about 400-500g/day. The growth rate will vary with breeds, for the bigger breeds the aim should be to wean calves at 3 months at approximately 80kg body weight.
Phases of Calf Feeding
The aim should be to switch young calves to cheaper feeds as early as possible so that more milk can be available for sale. However, the diet must be able to promote health and growth.
Calf Feeding Programs
While developing a calf feeding program the following factors should be considered.
- The calf has low immunity at birth and therefore must be given colostrum. The colostrum has antibodies that protect the calf against diseases the mother has been exposed to and their absorption is highest within 12 hrs after birth and very low after 24 hr. As such the calf must suckle colostrum immediately after birth and if necessary it should be given using a nipple bottle. The calf depends on the colostrum antibodies for about 2 weeks when it develops its own immunity. 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 and pass then on to their new
- The newborn calf is dependent on milk for nutrition and growth in its early life as the rumen is not functional. The suckling reflex forms a fold (groove) which serves as a pipe for delivering milk straight from the oesophagus to abomasum in young calves (bypassing fore- stomachs). Therefore, young calves should only be fed on liquid diets as the groove will not allow solids to pass.
- Calves secrete high amounts of lactase enzyme (breaks down lactose in milk to glucose and galactose to supply energy). The other carbohydrate digesting enzymes are low and therefore, milk which has a high lactose level should be fed to the calves. During formulation of milk replacers, the energy source should be milk lactose. Calves have no sucrase enzyme, and should not be fed on sucrose (ordinary sugar).
- Since the rumen is not functional, the calf cannot synthesize the B vitamins and they must be supplied in the diet. The diet of the newborn calf should contain milk proteins since enzymes to break down complex proteins do not develop until 7-10 days after
- Introduce calf to solid feed
As calf is introduced to solid feed, the rumen starts developing and the calf can be weaned as soon as it can consume enough dry feed (1.5% of body weight). It should be noted that dry feed should be introduced early, as solid feed is required for rumen development. Grain based diets promote faster growth of rumen papillae (which promotes rumen function) compared to roughages.
Calf Feeding Methods
After the first week during which the calf is left with the dam, several methods can be used for feeding depending on ease and convenience.
The calf is separated with the mother but during milking it is brought to to suckle. The amount of milk the calf consumes is difficult to quantify. Some farmers will allow the calf to suckle one quarter. This method is rarely used in commercial dairies. The disadvantage is that if the calf is not present, then the cow may not let down all the milk. This method is the best in terms of hygiene as the calf gets clean milk at body temperature.
Foster mother or multiple suckling
In farms where several cows give birth at the same time, one cow can be assigned to a number of calves depending on milk production. The calves suckle in turns ensuring that each calf only suckles the designated quarter. This method is not practical in small scale farms.
A plastic nipple is attached to a clean bottle filled with milk and the calf is trained on how to suckle. An alternative is to attach a nipple on a short plastic hose pipe and insert the same into a bucket. The calf is then trained on how to suckle.
The milk is placed in a clean bottle and the calf is fed directly from the bottle. This method is tedious and slow if many calves are to be fed. There is a high likelihood of milk going to the lungs via trachea.
This is the most commonly used method and milk is placed into a bucket and the calf is trained to drink (place finger in the milk and as calf suckles your finger it takes in milk). Stainless steel buckets, where available, should be used for hygienic reasons as plastic buckets are difficult to clean.
Whatever method is used, clean equipment should be used at all times. Sick calves should always be fed last to minimize cross contamination. Attempts should be made to feed milk at body temperature especially during the cold season.
Feeding during first week
Calves should be allowed to suckle obtain colostrum from their dams. If mother dies at calving or is unable to produce milk due to some condition, artificial or frozen colostrum or a contemporary mother (one that has given birth at the same time) can be used.
Colostrum serves two functions in new born calves, as a source of antibodies and also a rich source of nutrients (has high amount of energy and protein compared to milk).
Artificial colostrum does not supply the antibodies but is a good source of nutrients for new born calf, e.g. composition of artificial colostrum: one egg (protein source) + half litre fresh warm water + half litre whole milk (source of lactose and milk protein) + one teaspoonful castor oil (energy) + one teaspoonful of cod liver oil (energy).
Feeding during 2nd week to one month:
Calves should be fed milk at approximately 10% of their body weight. Milk can be mixed with other dairy products (whey or skim milk) at this stage and should be fed at body temperature.
Commercial milk replacers can be fed at this stage if they are available and cheaper as they would result in increased profits to the farmer and increase milk for human consumption.
The milk replacer should contain 22% protein (if all protein is from milk sources) or 24% when some plant protein is included (on DM basis). Mastitic milk can be fed to calves only if it appears normal and has low levels of antibiotics. The calf should be introduced to high quality pre-starters at this time.
High yielding cows may produce more colostrum than the calf can consume which can be preserved and fed later. The colostrum can be preserved by several methods. The most ideal is freezing but this may not be possible in small-scale farms without electricity supply. In such cases, the colostrums may be preserved through natural fermentation (storing at room temperature). Before feeding the preserved colostrum, it should be mixed with warm water at the ratio of 2 parts colostrum to 1 part water.
These are commercial products manufactured to resemble milk and are mostly used when there is no milk to feed the calf e.g where a cow is sick or died during calving. They are also used when demand and price of milk is high. Preserved colostrum should be used as much as possible before a farmer decides to use milk replacer. Milk replacers are always of lower quality than whole milk and should only be fed if they are cheaper.
A pre-starter is a high quality calf feed, which should be low in fibre and is almost similar to milk replacer and is usually fed during the second and third week. It is fed in a dry pelleted form or as a meal. It should be used early to stimulate calves to eat dry feed to enhance rumen development. It is estimated that it takes rumen growth about three weeks after the calf starts eating a handful of dry feed, thus the earlier they start the better.
The starter contains slightly higher fibre content compared with the pre-starter. At this stage the calf is consuming little milk and is in transition to becoming a ruminant.
Calves should be offered only high quality forages early in life and supplemented with concentrates (calf starter). If hay is used, it should be of high quality, fine texture, mixed with legumes and fed ad lib. If they are on pasture, it would be best to always graze calves ahead of adults to control parasites. Some of the common roughages offered to calves are sweet potato vines and freshly harvested and wilted Lucerne.
Calves should be offered fresh water in addition to milk. Lack of drinking water slows down digestion and development of the rumen, and hence the longer it takes before calves can be safely weaned. Between three weeks and weaning, calves’ water consumption usually increases and should be available all the time.
Table 2. Example of a feeding schedule for calves
|Age of calf (days)||Milk kg/day||Total Milk (kg)||Calf starter (kg/d)||Roughage|
|1 to 7
8 to 21
|22 to 42||6||126||0.5||Yes|
|43 to 56||5||70||0.5||Yes|
|57 to 63||4||28||1||Yes|
|64 to 77||3||42||1||Yes|
|78 to 84||2||14||1.5||Yes|
|Wean the calf|
This programme should result in growth rate of approximately 400-500 grams per day.
Weaning is the withdrawal of milk or milk replacer and the calf becomes fully dependant on other feeds. Traditionally, most dairy calves are weaned based on age, 12 weeks being the most common. Early weaning is possible if more milk is fed and calves introduced to pre-starter and starter early in life.
To minimise stress, weaning should be done gradually. The twice a day milk feeding should be reduced 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 calf attains twice the birth weight, when the calf can consume 1.5% of its bodyweight of dry feed and age of calf.
Early weaning (5 to <8 weeks) may be adopted to reduce the milk feeding period and labour required for calf rearing. This will require a specific feeding program using low levels of milk and high energy, high protein concentrates, preferably pelleted to stimulate rumen development. Liquid milk or milk replacer is reduced from 3 weeks of age to encourage the calf to consume and maximize intake of dry feeds.