>As to the second possibility, Collins and Caine6 list data from the horse pulling
contest at the 1925 Iowa State Fair showing that peak mechanical power output of
a horse is 12-14.9 HP. This effort lasted only a matter of seconds and is probably a
realistic estimate of peak performance
https://trove.nla.gov.au/newspaper/article/166523368
>pulling heavily loaded wagons of stone boats. However, it has been only since invention of the horse-pulling dymonometer four years ago that these contests have been carried on in a scientific manner.
Как можно понять из текста, все-таки полезная тяга на крюке, но несколько секунд.Животное имее анаэробную и аэробную энергетику, за счет запасов АТФ и анаэробного разложения глюкозы максимальная мощность мышц 12-15 л/с и достигается на несколько секунд.