Which of the following could be a cause of colic in horses?

Dietary changes can significantly disrupt a horse's digestive system, leading to colic. Horses have sensitive gastrointestinal tracts that require a stable diet. When there is a sudden change in their feed, such as a switch to a different type of grain, an increase in concentrates, or even changes in forage type or quality, it can result in digestive upset or imbalances. This may lead to gas accumulation, intestinal spasms, or other forms of colic.

Maintaining a consistent diet is essential for equine health, as horses are naturally designed to graze on forage throughout the day. Abrupt modifications can trigger reactions that the horse's digestive system is not prepared to handle. Hence, it is crucial to introduce changes gradually and to monitor any alterations in their routine that could impact their digestive well-being.