DETROIT — Detroit pet owners now have an option of a veterinarian who makes house calls. Dr. Marcy McKeithen is believed to be the first Black woman whose veterinary practice is mostly mobile. Carrying a weight scale and a backpack, McKeithen traverses Detroit and its adjacent suburbs to tend to the area’s pets. McKeithen, who earned her doctorate at the University of Florida, started her remote practice, Motor City Vet Care, last year. “There’s definitely a need for it … the pandemic aside,” McKeithen said. She has 25-30 pet clients and said she is adding more as her business grows. McKeith…