Bronchoalveolar lavage in the newborn foal.

This study conducted lung investigations called bronchoalveolar lavages on newborn horses to understand their susceptibility to respiratory diseases. They found that young foals have fewer alveolar macrophages, pivotal cells in lung defense, and these cells, particularly in foals aged two to three days, were deficient in chemotactic actions, affecting their disease-fighting ability.

Objective and Methodology

• The objective of this research was to investigate the immunity response in the lungs of newborn horses, termed foals, to understand their vulnerability to respiratory diseases. The method used was bronchoalveolar lavage, a procedure to examine the cells and other components in the fluid inside the lungs.
• This study involved performing two lavages, 24 hours apart, on 15 foals aged between 1 and 21 days. The results from these foals were compared with older horses aged 2-3 years.

Key Findings

• In the initial lavage, it was noticed that the alveolar macrophages – the first line of defense in lung health, were deficient in foals up to two weeks old compared to older horses. Particularly, foals aged 2-3 days had significantly impaired chemotactic functions, which are required for moving cells towards sites of infection or inflammation.
• However, in the second lavage, it was observed that alveolar macrophage count had increased and there was a dramatic surge of polymorphonuclear neutrophils (PMN). PMNs are white blood cells that are an essential part of the body’s immune response, providing additional support for the alveolar macrophage defense system. In older horses, the response of PMNs to lower respiratory tract disturbances was negligible.

Implication of Findings

• The findings from this study suggest that the numerical and chemotactic deficiency of alveolar macrophages in neonatal foals could contribute to their vulnerability to respiratory diseases.
• The research could potentially benefit improved veterinary care for newborn horses, providing insights into respiratory health during their initial days of life.