When specifying components for a hydraulic power unit, the prime mover is sized based on torque, speed, and power requirements of the hydraulic pump. This is fairly straightforward for electric motors bec ause they generally have a starting torque that far exceeds running torque.
Great Danes live on average 8 to 10 years, but have been known to reach 12 years of age. The Great Dane is subject to two main health problems that afflict 99% if them - Dysplasia and Bloat. Great Danes cost more to look after than smaller dogs. Their shots will cost more, especially their heartworm medicine.
most larger breeds live a short time... my book says Great Danes live to about 7-10 years. Yours is REALLY old for a Great Dane! Good Luck!