In qaliqat riḥālatuhā, the feminine past verb takes ‘her saddle’ as subject. In asbala naḥruhā, asbala is a form IV past verb with ‘her neck’ as subject. In ibtalla ... ḥizāmuhā, ibtalla is from form VIII and ‘her girth’ is the subject.
Three verbs describe three different visible effects upon one moving horse. Identifying their subjects prevents a translation from confusing the riding gear, neck and strap.