American Horse Slaughter Prevention Act of 2011 - Amends the Horse Protection Act to prohibit the shipping, transporting, moving, delivering, receiving, possessing, purchasing, selling, or donation of horses and other equines to be slaughtered for human consumption.
Authorizes the Secretary of Agriculture to detain for examination, testing, or the taking of evidence: (1) any horse at any horse show, horse exhibition, or horse sale or auction that is sore or which the Secretary has probable cause to believe is sore; and (2) any horse or other equine that the Secretary has probable cause to believe is being shipped, transported, moved, delivered, received, possessed, purchased, sold, or donated in violation of such prohibition.
Increases the cap on the amount of appropriations that may be used to carry out such Act.