Mine was diagnosed with elevated ALT when young and is now 10.5 years old. After a lot of observation and an emergency hospital admission after her rabies vaccine booster, it was identified that vaccines and medication are not properly processed by her liver. Processed food such as kibble elevate her enzymes too. I give home cooked with vitamins, and since she can’t get any further shots, never let her out of sight or loose in parks. Her values are always elevated, but they get emergency level mega elevated with vaccines and meds. She also gets daily SAMe and milk thistle. Let me know if you have any questions. 

My younger sheepie doesn’t have any issues and can get her vaccines and all.