Review of monensin toxicosis in horses

Effects of monensin on Na+/K+-ATPase and Ca++-ATPase activities in chick skeletal muscle and myocardium after subacute treatment

“…Smith and Galloway (1983) Neurotoxic effects of monensin (anorexia, thirst, dyspnea, motor incoordination, ataxia, flaccid paralysis, convulsions, increase in mortality rate, etc. ), have been reported by several authors, especially at the highest doses, on guinea-hen and turkey (Bassett et al, 1978;Senatorov et al, 2000;Stuart, 1978;Sutko et al, 1977;Naccari et al, 1996;Lehel & Laczay, 1995;Matsuoka et al, 1996;Prescott, 1997).…”

Ionophores

“…The greatest risk of intoxication is upon initial exposure, since animals will not consume highly contaminated feed. After an overdose, repeated daily intake of high levels of ionophores is not possible when anorexia occurs (Potter et al, 1984;Matsuoka et al, 1996).…”

“…Working with liver microsomes from horses, pigs, broiler chicks, rats and cattle, Nebbia and associates (2001) found that horses had the lowest catalytic efficiency which may explain the greater susceptibility of horses to the ionophore-induced toxicosis, relative to the other species. However, not all levels of monensin are toxic to horses (Matsuoka et al, 1996). In a subchronic feeding study in horses, all three horses provided a complete ration containing 330 ppm monensin (or 300 grams/ton, 10 times the maximum cleared level of monensin in complete feeds for feedlot cattle) and one out of three horses given 121 ppm monensin died during the 1-month feeding period.…”

“…Diarrhea has not been observed with either monensin or lasalocid but was reported with salinomycin and narasin (Whitlock et al, 1978;Novilla and Folkerts, 1986;Matsuoka et al, 1996;Novilla and Muller, 2003). Profuse sweating was also observed with monensin, salinomycin, narasin and laidlomycin but not with lasalocid toxicity.…”

Veterinary pharmacovigilance. Part 3. Adverse effects of veterinary medicinal products in animals and on the environment

“…They have narrow therapeutic indices, and are toxic to turkeys and mammals at relatively low doses (Todd et al, 1984;Oehme & Rumbeiha, 1999;Lindsay & Blagburn, 2001). Ionphore toxicity, often with fatalities and frequently as a result of accidental treatment or misuse, has been reported in a number of species including rabbits, dogs, cats, pigeons, quail, chickens, turkeys, ostriches, goats, pigs, sheep, cattle, camels and horses (Matsuoka, 1976;Collins & McCrea, 1978;Malone, 1978;Donev et al, 1980;Howell et al, 1980;Wilson, 1980;Hanson et al, 1981;Nuytten et al, 1981;Halvorson et al, 1982;Newsholme et al, 1983;Van Vleet et al, 1983;Wagner et al, 1983;Anderson et al, 1984;Todd et al, 1984;Gad et al, 1985;Reece et al, 1985;Bourque et al, 1986;Galitzer et al, 1986;Potter et al, 1986;Van Vleet & Ferrans, 1986;Egyed et al, 1987;Rollinson et al, 1987;Chalmers, 1988;Ficken et al, 1989;Drumev et al, 1990;Groom & Beck, 1990;Kavanagh & Sparrow, 1990;Sawant et al, 1990;Gregory et al, 1992;Hazlett et al, 1992;Mousa & Elsheikj, 1992;Novilla, 1992;Andreasen & Schleifer, 1995;Lehel et al, 1995;Plumlee et al, 1995;…”