Professors from premier veterinary school urge lawmakers to ditch captive-donor colonies, which critics dub ‘blood slaves’ In a blood fight that pits veterinarian against veterinarian, scores of vets are urging the Legislature to follow the lead of other states and outlaw “closed-colony” animal blood banks in California by 2022. “The current situation in California is egregiously unbalanced,” says the letter. “Hundreds of dogs — including many who have already endured months or years of suffering in the greyhound racing industry — are kept confined for months or years in situations…