Fracture rate in Thoroughbred racehorses is affected by dam age and parity.

The research article discusses the relationship between the age and parity of a horse’s mother (the dam) and the frequency of fractures in Thoroughbred racehorses. The results of the study show that first-born foals and those born to younger dams had a lower rate of fractures than subsequent foals and those born to older dams.

Background and Purpose of Study

This research was conducted to explore the connection between a dam’s age and the number of foals she has given birth to (parity), and the fracture rate of her offspring. The hypothesis was that the first-born foals and those from older dams would suffer a higher fracture rate than their counterparts.

Study Methodology

• The researchers monitored 335 Thoroughbred racehorses over two years in an observational cohort study.
• Data was collected from eight trainers, about the horses from the onset of training as yearlings.

Results

The results were analysed using multivariable Poisson regression and found that:

• First foals had a significantly lower fracture rate (RR=0.33; 95% CI=0.12, 0.89; P=0.02) compared to subsequent foals.
• The fracture rate decreased as the dam’s age increased (RR=0.91 per year increase in dam age; 95% CI=0.83, 0.99; P=0.03).

Implications

The findings suggest that aspects affecting skeletal development, such as maternal age and birth order, could impact the fracture rate in Thoroughbreds.

Recommendations for Future Research

The authors recommend that additional research be conducted on the intra-uterine and peri-natal determinants of injury risk later in a horse’s life. This could help to improve understanding of the factors that influence the risk of injuries in Thoroughbred racehorses and offer insights into potential preventative measures.