The objective of this study was to investigate some metabolic and clinical effects of feed deprivation in horses that were submitted for orthopaedic surgery.
The effects of preoperative feed restriction were investigated in 20 horses submitted for elective orthopaedic surgery. The patients were fasted from 12 h before until 4 h after surgery.
Serum free amino acids, glucose, free fatty acids (FFA), white blood cell counts, creatine kinase (CK) and aspartate aminotransferase (AST) were determined 24 h before surgery, 2 h after the end of anaesthesia and 24 and 72 h after surgery. Besides, abdominal sounds, appetite, faecal quality and body temperature were examined.
Serum free amino acids did not react homogenously. While asparagine, aspartic acid, glutamic acid, glycine, isoleucine, leucine, lysine, ornithine, serine, threonine, tyrosine and valine did not change or were on their preoperative level again 24 h after surgery. Arginine, citrulline, glutamine, histidine and methionine showed a significant decrease. In contrast to this, methylhistidine, phenylalanine, taurine and tryptophan showed a significant increase at this measurement time point.
Plasma glucose and FFA increased after surgery and returned to their preoperative levels 72 h after surgery.
A significant rise of the segmented granulocytes occurred 24 h after surgery, all other parameters of the leukogram did not exceed the physiological range. AST reached its highest activity 24 h after surgery, whereas CK activities were highest at 2 h after surgery.
Abdominal sounds were significantly reduced until 24 h after surgery, however, appetite was not depressed. Faecal quality was physiological after surgery. Mean body temperature stayed within the physiological range.
In conclusion, a relatively short perioperative fasting period had significant effects on the metabolic traits in horses, however the effects on physiological functions were minor. The consequences of major surgical procedures need to be addressed in future studies.