Equine poisoning by coffee husk (Coffea canephora) in northern Espírito Santo, Brazil

Resumo

Background: Brazil is the largest coffee (Coffea canephora) producer in the world, and Espírito Santo state is the second largest national producer of this commodity. Caffeine poisoning has been described in several animal and human species and is generally associated with accidental and/or intentional ingestion of caffeine-containing products. In horses, there are few reports in the literature about coffee poisoning, and most animals show clinical signs of excitability, involuntary muscle tremors, and chewing movements. Therefore, the objectives of the present study are to describe the clinical and epidemiological aspects of coffee (Coffea canephora) poisoning in horses in northern Espírito Santo, Brazil.

Cases: Two horses from northern Espírito Santo presented with clinical signs of excessive sweating, reluctance to enter the trailer, muscle tremors, aggression, incoordination, constant tremors of the lips and tongue, chewing movements, and falling. Clinical signs began after the animals were confined in stalls containing coffee husk (Coffea canephora) for at least one week. After three days in the stall, the horse began to show clinical signs characterized by excessive sweating, reluctance to enter the trailer, aggression, and incoordination. On physical examination, there was marked dehydration, tachycardia (120 bpm), tachypnea (80 mpm) and a body temperature of 39.1ºC. In addition, the animal had cecum and ventral colon hypomotility. The horse was treated as soon as it was admitted to the hospital with a 10 mL / h intravenous drip of Ringer lactate solution; 100 mL intravenous mercepton every 24 h; 10 mL intramuscular vitamin B1 every 24 h, and 1.1 mL intravenous acepromazine 1%; when it showed increased excitability, it was treated for neurological signs and recovered four days after admission. The second animal was a 3-year-old female Mangalarga Marchador horse, weighing 280 kg. The animal was confined for 30 days with coffee husk bedding. The horse was fed 8 kg of corn silage and 4 kg of granulated feed per day. After two weeks in confinement, the animal began to show severe incoordination, extremely aggressive behavior, muscle tremors, constant tremors of the lips and tongue, chewing movements, excessive sweating, and falling.

Discussion: The diagnosis of coffee husk poisoning was based on the epidemiological and clinical characteristics of the disease. In Espírito Santo, it seems to be common to use coffee husk as bedding material for horses, mostly as a substitute for sand and wood shavings. In the properties where the animals lived, the coffee was planted to sell, and the remains from production, especially the husks, were used as bedding for the animals. It has been reported that when horses are placed in stalls with coffee husks, they tend to eat the husks spontaneously, resulting in intoxication. The clinical signs observed in this study were similar to those described in horses experimentally intoxicated by the plant. The neurological effects observed were due to the action of caffeine as an adenosine antagonist. The observed neurological clinical signs observed in these cases were nonspecific, and other disorders of the equine central nervous system, such as rabies and leukoencephalomalacia, should be considered in the differential diagnosis of coffee poisoning. Coffee husks should not be used as bedding for horses, as it can cause animal poisoning and death due to the excitatory effects of caffeine, which can lead to spontaneous falls and serious trauma.