Specific immune response of mares and their newborn foals to Actinobacillus spp. present in the oral cavity.

This study investigated the immune response in horses to bacteria found in the mouth, termed Actinobacillus spp. It shows that many adult horses possess these antibodies, and can pass them to their newborns through their first milk, or colostrum.

Research Methodology

• As part of the experiment, oral swab samples, serum, and colostrum were collected from 15 mares and 14 of their newborn foals within 24 hours of birth.
• The presence of antibodies against Actinobacillus spp., bacteria isolated from the oral cavity of the horses, was tested. The method used for this testing was agar gel immunodiffusion, a widely accepted technique in immunology used for the detection and quantification of antibodies.

Results and Observations

• The study reported that antibodies against 48 of the 77 Actinobacillus isolates from all horses in the study were present in the serum of 13 mares and 9 foals. These antibodies indicate an immune response to the bacteria.
• In 11 mother-foal pairs, the antibody content of the foal serum was similar to that of the mare. In 9 of these instances, this was mirrored in the antibody content found in the mare’s colostrum.

Conclusions

• The results suggest many adult horses carry an immune response to Actinobacillus spp. that colonise the oral cavity. This implies that these horses possess antibodies against this particular group of bacteria.
• Importantly, the study shows that this immune response can be transferred from the mother to foal through colostrum, the nutrient-rich first milk produced by the mother following birth. This highlights the crucial role of colostrum in activating the immune system of newborn foals and providing them with their first line of defense against certain oral bacteria.