First I will tell you the stages of a dog and then we will discuss all of it with goods and bads so you can decide if you will adopt a puppy, an adult or a senior dog.
Stage 1: Neonatal - 0-2 weeks
Stage 2: Transitional - 2-4 weeks
Stage 3: Social - 3-12 weeks
Stage 4: Hierarchical - 3-6 months
Stage 5: Teenage - 6-18 months
Stage 6: Adult - 2-3 years
Stage 7: Senior - 5-10 years
Canine cognitive dysfunction syndrome is similar to human involutive psychosis similar to Alzheimer. The treatment with acetylcholine (ACH) failed because of the irreversible changes on the brain; however, some specialists recommend lecithin to reduce the risks of CCDS. CCDS is characterized by general decline of memory, learning, attention and perception with decreasing the capacity to adapt at different situations. In some cases is mention painful crisis, deafness or decreasing the visual ability (partial blindness) that lead to increasing irritability, anxiety, fear and at the end makes the dog become aggressive, even though he never was aggressive.
The Great Dane is typically a gentle giant, easygoing and mild-mannered.
He needs only moderate exercise, but does need space and shouldn't be cramped into studio apartments and postage-stamp yards. Above all, this sociable breed needs companionship. He doesn't do well when left alone.
With his deep, resounding voice, a Great Dane won't fail to announce visitors, but guarding and territorial instincts vary. Some lines and individuals are friendly with everyone, some are sensibly protective, while others are standoffish or skittish.
Dogs are not on a quest for world domination. They are not socialized wolves who are constantly striving to be ‘top dog’ over us, and they are not hard-wired to try and control every situation.
Contrary to what traditional training ideologies and much modern media would have you believe, most canine behavior problems stem from insecurity and/or a desire to seek and maintain safety and comfort – not from a desire to establish higher rank and be the ‘alpha’ over you.