The first feed is the most critical in a calf's life as calves are born with naive immunity. Through passive immunity antibodies are transferred from cow to calf through this feed which can only occur in a short window after birth. Therefore the ability to measure colostrum quality is vital to ensure the calf gets the best start.
What is Colostrum?
Colostrum, biestings and first milk are terms often used to describe the first milk produced by a mother for her calf. Colustrum contains immunoglobulin G (IgG) antibodies, which are essential for the passive transfer of immunity from the cow to calf. The concentration of IgG in colostrum can vary depending on several factors, such as the cow's nutrition, breed, age, and time since calving. Generally colostrum from mature cows is better in quality when compared to that of first time calvers.
As a general guideline, good quality colostrum for calves should contain at least 50 grams of IgG per liter of colostrum. This concentration of IgG is necessary to ensure that the calf receives adequate protection against infectious diseases and other health problems.
Use the 1,2,3 rule of colostrum feeding as follows:
1. Give the first feed from the first milk
2. Feed within two hours of birth
3. Provide at least three litres of good quality colostrum.
Many farmers continue to feed colostrum for up to 24 hours after birth as the gut can still absorb immune-related proteins and cells across its surface. Once passive immunity has been complete calves can remain on transition milk or be transferred to milk replacer.
Colostrum used for calves should:
- Be free from bacterial contamination, as bacterial infections can interfere with the absorption of IgG in the calf's gut.
- Be fresh, as colostrum can spoil quickly and lose its nutritional value.
- Be provided to the calf within the first 6 hours of life (ideally within 3), as the calf's ability to absorb IgG declines rapidly after this time.
How do you measure Colostrum Quality?
An inexpensive and quick way to measure colostrum quality is by using a Brix Refractometer. A Brix refractometer is a handheld device that measures the sugar content of a liquid, which can be used to indirectly estimate the quality of colostrum. Here are the steps to measure colostrum quality using a Brix refractometer:
Ensure that the colostrum sample is at room temperature (around 20-25°C) before testing. If the colostrum is cold, warm it up by placing it in a water bath or in a warm room for a few minutes.
Mix the colostrum well to ensure that it is homogeneous.
Place a few drops of the colostrum on the prism of the refractometer. Be careful not to overfill the prism or allow bubbles to form, as this can affect the accuracy of the reading.
Close the cover of the refractometer and look through the eyepiece. The scale on the refractometer will show the Brix reading of the colostrum.
To estimate the quality of colostrum, compare the Brix reading to the following guidelines:
- Poor quality colostrum: less than 22% Brix
- Good quality colostrum: 22-24% Brix
- Excellent quality colostrum: greater than 24% Brix
It is important to note that the Brix reading is only an estimate of colostrum quality, and should be used in conjunction with other methods such as measuring IgG concentration to ensure that the colostrum is of good quality.
How can Herdwatch help during calving
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