LIVER-BIOPSY TECHNIQUES FOR ADULT HORSES AND NEONATAL FOALS TO ASSESSCOPPER STATUS

Objective To evaluate standing, percutaneous, ultrasound-guided, trans thoracic liver biopsy in mares, and transabdominal, laparoscopically-g uided, liver biopsy under general anaesthesia in foals, as techniques for obtaining tissue for assessment of copper status. The techniques w ere evaluated with respect to ease of use and effect on the animal. Pr ocedure Twenty of 24 Thoroughbred mares and 21 of their foals were bio psied. The animals were part of a larger study of the effect of copper supplementation on copper status and the prevalence of developmental orthopaedic disease. Livers were also collected from unrelated horses and sampled to investigate the variability in the distribution of copp er in liver tissue. Result The biopsy technique caused no lasting effe ct on the mares, but there was an increased risk of viscus penetration associated with taking multiple biopsy cores. The use of ultrasonogra phy to scan the target area for the liver identified four cases that w ere not appropriate candidates for liver biopsy, because of large inte stine being located in the biopsy area. In the foals there were no ser ious postoperative adverse effects, nor was there any evidence of prob lems caused by the procedure when the abdomen was examined post-mortem at 5 months of age. In livers collected to investigate the variabilit y of copper concentration, copper appeared to be relatively evenly dis tributed through the liver. Conclusion Standing, percutaneous, ultraso und-guided, transthoracic liver biopsy in mares, and transabdominal, l aparoscopically-guided, liver biopsy under general anaesthesia in foal s are convenient procedures for obtaining liver tissue for assessing c opper status in horses. The use of ultrasound to identify liver tissue is recommended, especially in older mares.