Evaluation of non-steroidal anti-inflammmatory drugs in the treatment of asseptic acute laminitis caused by rumen acidosis after oligofructose overload in cattle

This study aimed to evaluate ruminal and systemic alterations of laminitis and ruminal acidosis oligofructose-induced in Zebu cattle; characterize laminitis clinical picture and compare methods of diagnostic; and to evaluate the treatment efficacy between three non-steroidal anti-inflammatory drugs (NSAIDs). Twenty-nine rumen-canulated Nelore heifers weighing 474.5 ± 58.5 kg were used. Induction was initiated with intraruminal administration of 0.765 g/kg oligofructose twice a day for three consecutive days, followed by single dose of 10.71 g/kg oligofructose administered 72 hours after beginning of induction. During the induction period the animals underwent clinical examination, blood and ruminal fluid collection daily and after induction were evaluated every 6 hours (during the initial 24 hours) and every 12 hours (up to 72 hours post-induction). Two heifers that did not present laminitis were discarded. Almost half of the animals (48.1%) had to be treated with bicarbonate and saline for correction of metabolic acidosis and dehydration. Due to this treatment the animals were analyzed in groups medicated (n=13) and unmedicated (n =14). After induction, the diagnosis of laminitis was confirmed after two positive responses to the pain sensitivity and locomotion score tests. Heifers with laminitis were randomly assigned to four groups that received, for three consecutive days, daily doses (intravenous) of the following medications: Control (8 mL isotonic saline; n=6); Flunixin meglunine (1.1 mg/kg; n=7); Ketoprofen (3 mg/kg; n=7) and Meloxican (0.5 mg/kg; n=7). After NSAIDs treatment the animals were evaluated every 12 hours up to 96 hours. The maximum fermentation of oligofructose occurred between the 6th and 12th hour post-induction with marked accumulation of lactic acid, intense decrease of anaerobiosis and temporary increase in ruminal osmolarity. In the medicated group, there was a positive correlation between ruminal and blood pH (r =0,90; P= 0,0040), and a negative correlation between blood pH and blood osmolarity (r =-0,69; P=0,0090) at the peak of ruminal fermentation. Both groups had a mild fever and respiratory compensation due systemic acidosis. Most animals developed laminitis 24 to 72 hours after induction in digits of two limbs and a small percentage (29.6%) had polysinovite in the tarsocrural joints. Using the pain sensitivity as gold standard, the best diagnostic method was the locomotion score, followed by the force platform and infrared thermography. Notwithstanding, the force platform was not sensitive to evaluate animals during the treatment of laminitis with NSAIDs. The three NSAIDs similarly reduced cortisol in relation to control group (P<0.05) and did not cause damage to the abomasal mucosa. Meloxicam was very effective in reducing hoof sensibility, improving in the same way as ketoprofen the locomotion score. These two drugs stimulated the return of appetite and improved attitude. For the treatment protocol of aseptic laminitis a NSAID should be included, with preference to meloxicam followed by ketoprofen. (AU)