ARTIFICIAL SYSTEMS OF CALF REARING
Any method of rearing calves that is not natural requires a very high standard of management and husbandry. Under good management, artificial systems work well and can be cheaper (he does not lose any milk income while rearing calves). To avoid unnecessary losses, however, close attention to detail is needed in relation to housing, feeding and hygiene.
Because of the importance of colostrum in the calf’s early development (and because this first milk must be kept out of the vat for the five days), the calf remains with its mother for this initial period.
Even though the calf cannot absorb the immunoglobulins in colostrum after six hours, they can still protect against gut infections. Also, very young calves have high-energy requirements and colostrum is the best material to meet this need. Finally, by giving the calf at least four days (or better still five) with its mother, you can achieve a better transition to either whole milk or replacer.
Teaching the Calf to Drink
After the calf is removed from its mother, it must be taught to drink from a bucket or teat within 24 hours and feeding intervals must be carefully monitored as any prolonged starvation at this stage can serious jeopardise calf survival.
To teach a calf to drink from a bucket, the best way is to place a small amount of warm milk in a bucket. Stand with the calf backed into a corner and its head between your legs. Moisten two fingers with milk and put them in the calf's mouth and wait until it begins to suck your finger. Once it is sucking, slowly lower the calf's mouth into the bucket where it will begin to suck up some of the milk.
Take care not to immerse its nostrils or it may inhale milk. When the calf begins to suck milk you can slowly withdraw your finger from its mouth. The bucket should be supported 30cm above the ground. Repeat this process until the calf is drinking by itself or until it has consumed at least half a litre of milk. Some assistance may then also be required for the next few feeds.
Teaching a calf to drink from a bucket takes time and patience. You will not be able to teach this in five minutes! It is no use getting impatient and angry at the calf because its whole instinct is to drink from above with the neck stretched out.
Once the calf does drink, however, it will drink quickly and will always remember the lesson learnt. An even better method is to use a teat. Simply attach a teat to a 2-litre container and put it in the calf’s mouth, it will usually begin to drink immediately.
A Basic Feeding Program
When feeding calves by bucket, many people tend to feed too much milk rather than too little. This is a common cause of digestive scours. Although ruminants have four stomachs, the young calf only uses one - the abomasum or true stomach - to digest milk. Only when the calf is eating solid food do the other three stomachs mature and start functioning. The single suckled calf running with its mother and getting all its milk from her will begin to pick at grass at one month old. However, it will not be until the calf is three months old that it will really start to eat grass in any quantity.
The functioning of the rumen, (the main organ for digesting grass) will begin to develop as soon as the calf eats some solid food. The changeover from milk to grass will be gradual, but can be hastened using pellets. Because of their high energy density a calf can be weaned onto pellets in 5 to 6 weeks, however, the rumen needs to develop both function and capacity, so a calf cannot survive on grass alone until about 8 to 10 weeks old.
In artificial rearing, the important thing to remember is to get the calf eating solid food as soon as possible, so that the rumen will develop early. In this way, the calf will be able to live on solid food when it is weaned away from milk.
However, whether using whole milk or replacer, sudden changes in any of the following should be avoided:
- Feeding times and intervals. The interval should be no greater than 16 hours and no less than 8 hours.
- Milk temperature. Calves drink warm milk more readily, but it should not be above 45oC. Always use a thermometer, as testing by hand is unreliable.
- Type of milk. That is colostrum to whole milk or whole milk to replacer, etc
With only a couple of exceptions, it is wise to make use of all available colostrum. It is unwise to use either colostrum or milk from mastitis cows or others that have received antibiotic treatment.
Antibiotics can damage the rumen flora in the calf and mastitis bacteria can be transferred to the undeveloped udder when calves suck each other’s teats. Bloody colostrum is best avoided. It can be used if necessary, but only when fresh.
After colostrum, whole milk is best, but if using a milk replacer, choose a good quality high-fat product as low-fat replacers will be unable to provide for the high energy requirement of young calves. Similarly, milk from the bottom of an unstirred tank will also be unsuitable for very young calves.
