Evaluation of equine breeding farm characteristics as risk factors for development of Rhodococcus equi pneumonia in foals.

This research article examines the characteristics of horse breeding farms that increase the risk of newborn horses, or foals, developing a type of pneumonia caused by the bacterium Rhodococcus equi.

Methods

• The research was conducted on 64 equine breeding farms with a total of 9,991 horses, including 2,764 foals.
• The researchers conducted a prospective matched case-control study. This means they compared pairs of farms where one had at least one foal with R. equi pneumonia and the other did not (the control).
• The data was collected in 1997 by veterinarians who filled out forms for each pair of farms, and was then analysed using conditional logistic regression analysis.

Results

• Findings revealed that farms with greater than 200 acres of land, over 60 acres used for horse husbandry, more than 160 horses, at least 10 permanent resident mares, more than 17 foals, over 0.25 foals per acre, and the presence of transient mares (those brought temporarily for breeding or foaling) and their foals, are more likely to have foals develop R. equi pneumonia.
• Farms affected by R. equi were also more likely to be greater than 200 acres in size and have more than 10 resident dam-foal pairs.
• In contrast, control farms were more likely to have at least 75% of their dam-foal pairs as permanent residents.

Conclusions

• The study concluded that breeding farms with large acreage, a large number of mares and foals, high foal density, and a population of transient mares and their foals are at high risk for foals developing pneumonia caused by R. equi.
• This research is invaluable for equine breeders, equine health professionals and researchers as it identifies key risk factors which they can use in their prevention strategies against Rhodococcus equi pneumonia in foals.