EFFECT OF OXYTETRACYCLINE ON METACARPOPHALANGEAL AND DISTAL INTERPHALANGEAL JOINT ANGLES IN NEWBORN FOALS

Thirty-five newborn foals were assigned to 1 of 3 groups and treated w ith 0.9% NaCl solution (saline; group 1; n = 12), oxytetracycline (44 mg/kg of body weight; group 2; n = 12), or 2-pyrrolidone (oxytetracycl ine vehicle; group 3; n = 11) in saline solution during the first 36 h ours after birth. Serum biochemical analyses were performed on samples obtained from group-1 and group-2 foals before treatment and 24 and 9 6 hours after treatment. Lateral to medial radiographic views of the f orelimbs were obtained before treatment and 24 and 96 hours after trea tment in all foals. Metacarpophalangeal and distal interphalangeal joi nt angles were measured from the radiographic images. Significant chan ges in blood chemistry values, other than those typically observed in newborn foals, were not detected. A significant decrease in mean metac arpophalangeal joint angle was observed in foals 24 hours after treatm ent with oxytetracycline, compared with that in foals of groups 1 and 3. The mean metacarpophalangeal joint angle returned to pretreatment v alues by 96 hours. Oxytetracycline appears to he an effective method f or obtaining a short-term moderate decrease in metacarpophalangeal joi nt angle in newborn foals.