An easy method to determine the IgG in the blood of newborn foals. The test strips are interpreted using the VMRD reader and provide a reliable, objective value. This data can be used to determine whether therapy should be initiated to provide the foal with sufficient antibodies.
IgG in colostrum
The plasma cells in the mammary glands produce immunoglobulins that are absorbed by the foal from the colostrum. The amount of immunoglobulins ingested by the foal depends on the level of immunoglobulins in the colostrum, the amount of colostrum produced by the mare, the amount of colostrum the foal drinks in the first 24 hours and the foal's absorption of IgG from the colostrum. If any of these factors are insufficient, the foal will not receive enough immunoglobulins and this can have major consequences for the health of the foal. In up to 25% of foals, the intake of immune globulins is insufficient.
Importance of sufficient intake of colostrum
In horses, there is no transfer of immune globulins through the placenta and their own immune system takes up to 2 months to provide enough immunoglobulins to protect themselves. To have adequate protection in the first stage of life, foals must receive sufficient colostrum.
Foals should receive at least 2 liters of good quality colostrum in the first 24 hours after birth. With good colostrum quality, the specific gravity of the first colostrum after birth is 1060.
Especially the first hours after birth are crucial for the intake of sufficient IgG, as the composition of colostrum changes rapidly after birth. At birth the mare's colostrum contains on average 4000-9000 mg/dl IgG, 8-19 hours after birth this has already decreased to 1000 mg/dl.
When is colostrum intake sufficient?
In foals, an indication of immunoglobulin uptake can be obtained as of 8 to 12 hours after birth. If less than 400 mg/dl IgG is measured in the blood at this time, uptake may not have been sufficient. For early testing, keep in mind that plasma concentrations may still rise if colostrum has been ingested during the blood collection period.
The most reliable period to assess colostrum intake is from 18 hours, if less than 800 mg/dl IgG is present in the blood at that time, insufficient transmission of passive immunity has occurred.
The VMRD Foal IgG Test
The VMRD Foal IgG tests provides fast, reliable and more accurate results than visually interpreting the test strips. The test strips are user-friendly, they can be stored at room temperature and can be read with the VMRD reader that is also used for SAA determination. The VMRD reader displays results in ranges of 200 mg/DL, as shown below:
- <200
- 200-400
- 400-600
- 600-800
- 800-1000
- >1000
