CALGARY — A Chinese ban on Canadian beef that industry officials expected would be short-lived remains in place 17 months later, and industry representatives say they remain in the dark about the reasons. China has been blocking beef shipments from Canadian processing plants ever since an atypical case of BSE, or mad cow disease, was found on an Alberta farm in December of 2021. At the time, Canadian officials expressed little concern that the case would have lasting market impacts. Atypical BSE develops spontaneously in about one in every one million cattle and unlike the classic BSE strain — which…