Colostrum – what is it?
Colostrum or first milk, as it is also known as, is generated by the animal during the late stages of pregnancy and then produced by the mammary glands immediately following the delivery of the new born. A healthy newborn will begin to suckle 1-2 hours after birth.
Why is it important?
Most animals are born without any antibodies which results in them having no way of fighting off disease. Colostrum contains high levels of nutrients which allows newborns to gain strength and grow. It is also rich in antibodies which are also known as immunoglobulins. While some of these antibodies help protect newborn from diseases, others such as secretory immunoglobulins help protect the mucous membrane layer of the throat, lungs and intestines. As well as high level of nutrients and antibodies colostrum also contains a large number of leukocytes or white blood cells which protect the body from viral or bacterial infections and foreign materials.
Therefore, in order to provide the newborn with the best start in life, promote growth and resistance to diseases, it is essential that the newborn animals receive colostrum. They must receive it within the right time period and get enough of it to prevent them from becoming weak, ill and possibly dying.
The right time
To ensure maximum absorption newborn animals must receive colostrum within the first 6 hours after birth. This is due to the gut of a newborn being highly permeable after birth which enables it to absorb large molecules very efficiently. However, after 6 hours from birth the permeability of the gut gradually decreases, allowing less antibodies and nutrients to be absorbed into the body. Research done by Animal Health Ireland, shows that an easy way of remembering the time frame and amount of colostrum needed for large animals is by using the simple 1-2-3 colostrum rule.
Colostrum – 3 main rules
- Colostrum should always be the first milk, for the first feed
- Colostrum should be given within the first 2 hours after birth
- At least 3 litres must be given at the first feed.
For more information on colostrum click here
Effects of no colostrum
If within 2-4 hrs after birth the newborn does not nurse, stand well, is weak or has abnormalities then colostrum should be fed by tube or bottle. The critical influence on neonatal survival, is to ensure that good and adequate quality of colostrum is provided. If this does not happen then failure of passive transfer occurs. To assess if complete failure of passive transfer has occurred in a newborn, a blood test is carried out to calculate the number of maternal antibodies that have successfully transferred into the newborns blood stream.
The failure of passive transfer test can be carried out as early as 6 hours after birth, but is normally done between 18 – 48 hrs after birth. If the immunoglobulin concentration is less than 400mg/dL at 24 hours old then complete failure of passive transfer has occurred.
Failure of passive transfer of antibodies occurs in 10 to 20% of newborn foals. When this occurs a plasma transfusion is needed to boost the immunoglobulin and antibody levels in the newborn. Around 2-4 litres of plasma at a slow infusion rate of 0.5ml/kg over 10 – 20 minutes is typically needed to be transfused into a large newborn animal to bring it up to 800mg/dL. While the transfusion is taking place the newborn should be monitored continually for signs of transfusion reaction. Signs of a transfusion reaction could be muscle spasms, increased heart and /or respiration rate, pale mucous membrane or the newborn collapsing. If no signs of reaction occur during the slow infusion, then the rate of infusion for the remainder of the transfusion can be increased to 40ml/kg over 60-90 minutes.
For more information on Failure of passive transfer click here
For an interesting story about how colostrum and a plasma infusion played a vital role in the survival of an orphaned foal at Caddy vets click here