Chocolate can affect canines in different ways--from the mildly upsetting to the downright dangerous
A small dog should be belly-up after eating a handful M&M's, at least according to conventional wisdom. But watching "Moose," a friend's five-pound Chihuahua, race around a living room after his sweet snack makes one wonder: Is chocolate truly poisonous to dogs?
Dogs and humans have similar tastes. Like us, they seek out sweets and have no problem indulging. But unlike humans, our canine companions experience dangerous effects from eating chocolate—it can poison them and in some cases is lethal. The hazard, however, is probably overblown, says Tim Hackett, a veterinarian at Colorado State University. Chocolate's danger to dogs depends on its quantity and quality. Large dogs can usually handle a small amount of chocolate whereas the same helping could cause problems for Moose and his pint-size kin.
Chocolate is processed from the bitter seeds of the cacao tree, which contain a family of compounds known as methylxanthines. This class of substances includes caffeine and the related chemical theobromine. Both molecules bind to receptors on the surfaces of cells and block the natural compounds that normally attach there. Low doses of methylxanthines can lead to vomiting or diarrhea in dogs, and euphoria in humans. Chocolate contains a significant amount of theobromine and smaller amounts of caffeine. If a large quantity of theobromine or caffeine is ingested, some dogs will experience muscle tremors or even seizures. These chemical constituents of chocolate can cause a dog's heart to race up to twice its normal rate, and some dogs may run around as if "they drank a gallon of espresso," according to Hackett. Moose, it seems, was on a "theobromine high."
Dogs are capable of handling some chocolate, but it depends on the animal's weight and the type of chocolate it eats. Unsweetened baking chocolate contains more than six times as much theobromine as milk chocolate, although amounts vary between cocoa beans as well as different brands of chocolate. Less than four ounces of milk chocolate is potentially lethal for Moose and other small dogs, according to the ASPCA Animal Control Poison Center.
Around every confection-centered holiday—Valentine's Day, Easter and Christmas—at least three or four dogs are hospitalized overnight in the animal medical center at Colorado State. But in 16 years as an emergency and critical care veterinarian, Hackett has seen just one dog die from chocolate poisoning, and he suspects it may have had an underlying disease that made it more vulnerable to chocolate's heart-racing effect.
Dogs that eat a small amount of chocolate should be able to filter the methylxanthines through their body and avoid veterinary treatment. But more acutely poisoned dogs are generally treated by inducing vomiting and administering activated charcoal to absorb any
methylxanthines remaining in the gut or that may be circulating through the dog's digestive system.
Ultimately, Moose survived his cocoa snack. But no matter how you bake it, wrap it or melt it, chocolate and Moose don't mix.
译文:
巧克力对狗的多重影响：小到心神不宁，大到致其死亡
巧克力对狗的多重影响：小到心神不宁，大到致其死亡
在美国，流行一种说法：体型小巧的宠物狗不能吃巧克力，否则就有丧命的危险，哪怕只吃了一丁点。我的朋友养着一条“吉娃娃”，有一次我亲眼见到这条小狗在吃过巧克力后，在房间内疯跑。难道甜美的巧克力真是狗儿的致命毒药？
犬类陪伴着人类已经走过了漫长的岁月，也许正是这个原因，人与狗有着相似的食物偏好。然而对于甜食，虽说人类可以轻松消化，狗儿却不能，人类最爱吃的巧克力对它们还有毒害作用，有时甚至会夺走它们的生命。狗儿食用的巧克力越多、越正宗，它受到的伤害也越大。可能由于抵抗力的原因，大型犬吃一点巧克力不会发生什么大问题，而小型犬的主人就应该特别注意了，不能让你的爱犬食用一丁点儿巧克力。
巧克力由可可豆加工而成，含有多种甲基黄嘌呤（methylxanthine）的衍生物，咖啡因和可可碱就属于这类物质。这些物质会与细胞表面的某些受体结合，从而阻止动物体内的天然物质与受体结合。服用小剂量的甲基黄嘌呤类物质，狗儿会呕吐、腹泻，而人类却会有一种欣快感。巧克力含有大量的可可碱和少量的咖啡因，如果狗食用过多的巧克力，就会发生肌肉痉挛，甚至休克。服用可可碱和咖啡因后，狗的心跳速率会骤升至平常的两倍以上，某些狗还会四处狂奔，就像喝了一大杯浓咖啡。
狗也能消化少量的巧克力，具体能消化多少，则要看它的体型和食用的巧克力种类。无糖烘焙巧克力（Unsweetened baking chocolate ）含有的甲基黄嘌呤的量，是奶油巧克力的6倍以上。据专家透露，对一些小型犬而言，4盎司（约120克）的奶油巧克力就可能是致命剂量。
在每一个喜庆气氛浓厚的节日，比如情人节、复活节、圣诞节，都会有不少主人抱着自己的爱犬跑到动物医疗中心，为自己的狗狗看病。Hackett 已经是有着16年从业经验的兽医，他说：“虽然不少狗生病，但是真正死于巧克力的，这16年来我只见过1条。巧克力对狗的毒害作用，可能是一种慢性过程。”
如果只是吃了少量的巧克力，小狗尚能抵抗，不用劳烦兽医们。倘若吃得又急又多，那就只有逼它吃下活性炭，把巧克力中的甲基黄嘌呤类物质清除掉，避免通过消化系统进入血液循环。尽管巧克力不能在刹那之间夺走小狗们的生命，主人们还是少给自己的爱犬喂食巧克力。
最终，我朋友的狗还是幸存下来了。不过无论你是把巧克力烘一下、包一下还是融化掉，巧克力都不是狗狗的美味佳肴哦。