Inflammation and increased numbers of bacteria in the lower respiratory tract of horses within 6 to 12 hours of confinement with the head elevated.

The study shows that keeping horses in confined spaces with their heads elevated can increase bacteria and inflammation in their lower respiratory tracts within 6 to 12 hours. This effect occurs with routine management procedures, such as transportation, and continued even when horses were given short breaks to lower their heads. However, the bacteria and secretions were cleared within 8 to 12 hours once the horses’ heads were returned to normal positions.

Research Purpose and Method

• The research aimed to determine how confining horses with elevated heads impacts their lower respiratory tracts. This is a common situation for horses during transportation or other management procedures.
• The researchers confined horses with their heads lifted for periods of up to 24 hours and closely monitored changes in bacterial numbers in the horses’ lower respiratory tracts.

Research Findings

• The research revealed a substantial increase in bacterial numbers (up to a billion colony forming units per millilitre in samples) in most horses as soon as 6 to 12 hours of confinement.
• The major types of bacteria isolated from these horses included Pasteurella/Actinobacillus spp and Streptococcus spp.
• Attempt to help horses by lowering their heads every 6 hours for 30 minutes, possibly to aid in drainage, didn’t prevent multiplication of bacteria. The bacteria grew to levels comparable to those seen in horses that kept their heads raised for an entire day.

Implications and Conclusions

• As soon as horses were released from confinement and allowed to hold their heads normally, the built-up secretions and bacteria in the lower respiratory tract cleared up within 8 to 12 hours.
• This suggests that keeping a horse’s head elevated during confinement can result in significant bacterial contamination and growth in the lower respiratory tract.
• These findings hold implications for the welfare and care of horses during transportation or other scenarios that may require prolonged confinement with an elevated head.
• The study supports the importance of letting confined horses lower their heads regularly and could inform best practices in horse management and care, especially in transport scenarios.