Fasting horses perioperatively decreases manure production and increases time to manure output postoperatively: a controlled randomized trial.

The study explores the effects of different feeding regimes on anesthetic complications, manure output, and colic occurrences in horses undergoing elective orthopedic surgery. It found that horses with continuous access to hay before and after anesthesia produced more manure and passed it sooner than horses who were fasted, without any rise in anesthetic complications or postoperative problems.

Overview of Research Design and Methodology

• The research involved 45 horses scheduled for elective orthopedic procedures. The horses were randomly assigned to one of three feeding groups: not fasted, fasted muzzled, and fasted not muzzled.
• The ‘Not Fasted’ group continuously had access to hay pre-surgery and post-surgery, while the ‘Fasted Muzzled’ group was made to fast 10 hours pre-surgery and was slowly refed post-surgery with a muzzle applied. The ‘Fasted Not Muzzled’ group was treated the same as the ‘Fasted Muzzled’ group except without a muzzle.
• All horses followed the same standard anesthetic protocol and various outcomes such as anesthesia time, arterial oxygenation, hypotension duration, perioperative manure output, time to first manure passage post-surgery, pain scores, and colic proportion were studied and compared across groups.
• Statistical tests were deployed to assess the outcomes and a P-value of less than or equal to .05 was considered statistically significant.

Key Findings

• No differences in pain scores, arterial oxygenation, hypotension or colic were found across the three groups.
• The Fasted Muzzled and Fasted Not Muzzled groups saw a considerable decrease in post-surgery manure weight and pile count in comparison to the Not Fasted group.
• The time taken for the first post-surgery manure passage was significantly shorter in the Not Fasted group than in the Fasted Muzzled and Fasted Not Muzzled groups.

Conclusions and Implications

• The study concluded that continuous access to hay before and after anesthesia lead to a higher manure output and faster manure passage post-surgery compared to fasting horses.
• Importantly, this increased manure output did not translate into detrimental effects on anesthetic parameters or postoperative complications.
• The findings suggest that permitting constant access to hay preoperatively and postoperatively supports manure production in healthy horses without raising anesthetic complications.