Failure of passive transfer in foals: incidence and outcome on four studs in New South Wales.

The research focused on understanding the regional incidence and effectiveness of different treatments for failure of passive transfer (FPT) in newborn horses (foals). It was found that treating foals with FPT may help to decrease the risk of severe diseases in the future.

Study Design and Methods

• The study involved 88 foals and 57 mares selected from four horse breeding farms in New South Wales. These foals were monitored within the first 72 hours of their life to assess their immunity levels.
• Key measurements taken include the serum IgG (Immunoglobulin G) and total serum protein (TSP) within the first 72 hours of life. These measurements are used to determine the immunity status of the foals. IgG is an important type of antibody that is necessary for fighting bacterial and viral infections.
• The quality of the colostrum from the mares was also tested through determining its specific gravity. Colostrum is the first milk a mare produces after giving birth, and it’s vital for providing the newborn foal with initial immunity.
• FPT and partial failure of passive transfer (PFPT) were diagnosed on the basis of serum IgG concentrations below 4 g/L and between 4 to 8 g/L respectively.
• A subset of owners made the decision to treat their foals that were diagnosed with FPT. These foals were treated by receiving 1 to 2 liters of plasma, which had a high TSP concentration of above 70 g/L.

Results

• The study found that 14 foals (16%) presented FPT, while 15 foals (17%) exhibited PFPT. There were crucial differences between the TSP concentrations in foals with FPT, PFPT and those who received enough passive immunity.
• Out of the 57 mares, 16 (29%) displayed pre-suck colostral specific gravity below 1.060. As a result, 12 out of these mare-raised foals had FPT or PFPT.
• The overall occurrence of severe disease, categorized by a sepsis score over 11, positive culture of bacteria from blood, or disease requiring hospitalisation, amongst all foals in the first two months of life was 10%.
• Interestingly, none of the 9 foals that were treated with plasma for FPT developed severe disease. However, PFPT foals showed a significantly increased susceptibility to severe disease in comparison to healthy foals.

Conclusions

• The study highlights the significance of treating FPT in foals as it could aid in reducing the incidence of severe disease later.
• The results also suggest pre-suck colostral specific gravity and foal TSP as reliable indicators to predict the likelihood of FPT and PFPT.
• The researchers emphasize that even though the population of the foals studied was small, the outcomes spotlight the necessity for optimal management practices in decreasing the incidence of FPT and associated diseases.