Introduction:
Colic remains a major cause of emergency intervention in horses, and feeding practices are a critical component of risk management. Freshly cut, semi-dried grass is often considered a convenient feed source, yet early fermentation processes may predispose horses to gastrointestinal disturbances. This study investigated microbiological, physicochemical, and sensory changes in grass clippings during natural drying to identify factors contributing to colic development.
Methods:
Grass samples were collected near Stable X during the seasonal peak of grass-related colic. The grass samples were collected at three time points (0 h, after 12 h and 24 h of fermentation), and three independent replicates were obtained at each time point, resulting in a total n=9. Microbiological evaluation was performed using Columbia Blood Agar under anaerobic conditions, followed by Gram staining. Feed quality assessment included dry matter (DM), pH, and concentrations of nitrogen, phosphorus, and calcium. Organoleptic characteristics were also documented. Clinical colic cases recorded in the LSMU Large Animal Clinic during the same period were reviewed to support laboratory findings.
Results:
Across all replicates, Clostridium botulinum was not detected. Instead, Actinomyces spp. and non-specific Gram-positive rods proliferated consistently, with the highest bacterial load in the 24-hour samples. DM displayed a uniform pattern: a slight increase at 12 hours, followed by a statistically significant decline at 24 hours (mean decrease 26.5%, p < 0.05), indicating active microbial fermentation. Nitrogen and phosphorus increased, while calcium decreased; pH remained acidic. Sensory evaluation revealed progressive heating, darkening, and development of spoilage odour. Clinical data demonstrated recurrent episodes of gaseous distension and reduced intestinal motility, consistent with laboratory findings.
Conclusions:
The results confirmed that freshly cut grass undergoes rapid, reproducible fermentation within 24 hours, producing conditions that predispose horses to fermentation-related colic. Semi-dried grass clippings represent a consistent feeding risk and should be avoided. Consider it as a hypothesis and expand the studies.
