Risk factors for post-partum colic in a population of UK and Irish Thoroughbred broodmares.

BACKGROUND

Broodmares are at increased risk of gastrointestinal colic. However, colic risk factors specific to this population have not been investigated.

OBJECTIVE

To investigate horse- and management-level risk factors for post-partum colic in a cohort of Thoroughbred broodmares in the United Kingdom and Ireland.

STUDY

DESIGN

Prospective, nested case-control study.

METHODS

Twenty-nine Thoroughbred stud farms in the United Kingdom and Ireland were recruited, and 1044 mares were followed over the 2021 and/or 2022 foaling seasons. Data were collected on signalment, medical and management history for post-partum colic mares and matched (3:1) controls. Multivariable analysis was conducted using conditional logistic regression.

RESULTS

Due to strong collinearity between days post-partum and time spent stabled, two multivariable models were built. Days post-partum (Model 1: OR 0.9, 95% CI 0.8-0.9; p < 0.001) and increasing hours stabled (Model 2: OR 1.2, 95% CI 1.1-1.3; p < 0.001) were strongly associated with increased risk of post-partum colic. Colic risk was highest immediately post-partum, with reduction in likelihood of colic up to 50 days after foaling. NSAID use in the previous 28 days (Model 1: OR 6.2, 95% CI 2.0-65.5; Model 2: OR 4.1, 95% CI 1.1-15.0; p = 0.048) and a history of previous colic (Model 1: OR 7.4, 95% CI 1.2-7.9; Model 2: OR 5.3, 95% CI 1.7-17.1; p = 0.01) were also associated with increased colic risk. Calcium supplementation was associated with increased likelihood of post-partum colic in Model 1 only (OR 4.4, 95% CI 1.3-15.7; p = 0.04).

MAIN LIMITATIONS: Mares comprised a small sub-population of UK and Irish Thoroughbred broodmares. Pre-partum colic was not investigated.

CONCLUSIONS

Maximising turnout in post-partum broodmares may reduce colic risk, immediately post-partum and up to 50 days. Broodmares who have recently received NSAIDs, have a history of colic or are receiving a calcium-based supplement may be at increased risk of post-partum colic.