I believe that animals can be used for objects of sport and entertainment. So long as no harm is done upon the animal. They play in their own sports, such as, agility competitions, rodeos, horse racing, dog racing, pig racing, etc. We also use horses in polo. We are not killing or doing harm to these animals. As far as entertainment goes, we ride horses for leisure, play fetch with our dogs, and heck, we even sit around on the computer watching funny cat videos. These are all forms of entertainment.
Animals being used for entertainment are part of the human existence. We readily ask a poor person to be a dancer on a stage if they can find no other job rather than to let them improve themselves through social programs to give them alternatives. Animals used for sport and entertainment, especially race horses, are often treated better than the human who's forced to dance for his meal. Ethically speaking I have no quarrel so long as this situation remains.
I believe it is ethical to use animals for objects of sport and entertainment, as long as the safety of the animal is ensured. I don't see animals being used much in the way of sports unless we're referring to hunting or maybe polo. Animals are common in the entertainment industry and their safety generally has to be guaranteed.
I am assuming that the word "entertainment" here means for hunting. I use my pets for entertainment all the time because they are fun. I don't think, however, that hunting just for sport is ethical. If you need them for food and eat the food then it is okay. Otherwise, no!
I firmly disagree with the statement that it is ethical to use animals as objects for sport and entertainment. An animal is a living breathing thing and it should be treated with respect. I do not feel that animals should be used for our entrainment and for sports because it is cruel treatment to these defenseless animals. We would not treat a human in this mannor so we should have the same respect for another living breathing thing.