Colostrum is the cow’s first milk after calving and is present for up to 6 milking’s. It contains antibodies and growth factors and is superior in nutritional value when compared with whole milk. At birth a calf’s immune system is not fully developed. Colostrum provides passive immunity (immunity from the antibodies in the milk from the mother) from the dam (cow that gave birth) to the newborn calf through intestinal absorption of antibodies. It is recommended that it should be fed for the first 3 days after birth. It is crucial that calves receive colostrum after birth as they are born without an active immune system meaning they are highly vulnerable to infection. Calves should receive 10% of their body weight of colostrum in the first 10 hours.
The quality and volume of the colostrum produced by a cow depends on its lactation number (how many times it feeds the calf) and breed. There are some vitamins (vitamins A, D, E) which are not able to pass through the placenta to the calf, thus meaning the calf is born with low levels of vitamins. Good quality colostrum now will be the ideal source for such minerals therefore adequate consumption boost initial levels of these vitamins. Most of the essential minerals and vitamins are substantially more concentrated in colostrum than in milk. For example colostrum usually contains 6-10 times the amount of vitamin D present in ordinary milk.
Inadequate feeding, or low quality colostrum is a primary cause of low immunity in calves. This may increase susceptibility to scour, pneumonia, navel-ill, joint-ill etc. On farms colostrum management is the single most important management factor in determining calf health and survival. A failure of passive transfer of antibodies from colostrum, contributes to excessively high pre-weaning mortality rates and other short- and long-term losses associated with animal health, welfare, and productivity.
Colostrum management programme
A successful colostrum management program requires farmers to consistently provide calves with a sufficient volume of clean, high-quality colostrum within the first few hours of life. As time from birth increases the ability of the calf to absorb the antibodies is reduced. Absorption is greatest in the first few hours of life and starts to decline progressively after 4 to 6 hours, and ceases after 24 hours from birth. Therefore, it is critical to feed colostrum as soon as possible after calving to ensure maximum immunity is acquired, as the most critical time in the life of a calf is during the first few days, when morbidity and mortality are greatest. Ideally calves should be given 2 – 3 liters of colostrum by esophageal tube or by nipple feeding within four hours of birth with a total of 4 liters within 12 hours of birth.
Leaving calves to suckle colostrum from their dam is not recommended as there is no guarantee that they will have a sufficient intake. The amount of colostrum that calves drink voluntarily does not change within the first 4 hours after birth, so that there is no benefit in delaying first feeding. It should also be noted that there is evidence to suggest that the concentration of antibodies in colostrum decreases by 3.7% per hour from calving (Morin et al., 2010). Therefore time of first milking is the most crucial factor regarding colostrum quality that can be influenced on farm.
Frozen colostrum can be stored at -18oC to -25oC for at least a year without changing its quality. Slow thawing at temperatures below 50oC does not affect colostrum, while temperatures above 50oC cause reduced quality and lower the amount of available antibodies (i.e. do not use a microwave to defrost the colostrum).
Importance of colostrum
Colostrum is important because it is a rich source of:
- Fat and lactose – this provides energy as the newborn calf is born with low energy stores and poor insulation.
- Protein – for protein synthesis and muscle growth.
- Immunoglobulin (antibodies) provide passive immunity and help fight infection.
- Vitamins and minerals which provide high levels of vitamins A and E for health and immunity.
Anatomy of colostrum and the calf`s feeding system
Early feeding of colostrum is essential because when the calf is born its intestines are able to absorb the antibodies that are present in the cow’s colostrum, but the cells mature rapidly and lose their ability to absorb these antibodies. After 24 hours only a small percentage will reach the calf’s blood stream so will provide less immunity. The calf should receive colostrum quickly after birth to have the best chance of absorbing as many antibodies as possible. Tube feed calves colostrum if necessary.
Colostrum feeding management
Calves should have a daily routine, with the same person feeding them every day. The calf rearer should be quiet and relaxed around the calves as quiet handling and routine will reduce the stress and they will be more likely to drink their share of milk. The rearer should have plenty of time to do their job and complete their daily checks as it is important that no part of the rearing program (feeding, cleaning or animal health) is overlooked. In the first 10 hours of life the calf should have at least four litres of colostrum (two liters twice a day) and their navel sprayed with iodine. Check navels at three days and if the cord is bigger than the little finger then it will require veterinary attention.
Colostrum should be good quality, and from the first milking, as subsequent milk production contains lower antibodies and nutrients. The quality of colostrum is affected by the number of pregnancies the cow has had; older cows have been exposed to more infections than heifers and therefore have higher levels of antibodies in their colostrum.
A supply of frozen colostrum should be kept on hand for feeding when fresh colostrum is not available. Take care when thawing that it is done gradually. Overheating the colostrum will destroy the antibodies and supply lower immunity to the calf. Colostrum should be good quality, fed in sufficient quantities and fed quickly. Without this passive immunity from colostrum, calves are much more susceptible to disease and the risk of mortality is increased. Colostrum should be fed for the first three to four days after birth before changing to whole milk or milk replacer.
What to do when mother dies
Try to ensure that at birth the calf is fed colostrum obtained from another cow that has calved.
- Feed warm colostrum using a baby’s feeding bottle.
- After your orphaned or abandoned calf has taken colostrum, feed it milk until it is about 16 weeks old.