A method of treating a symptom of neurodegenerative disease in a mammal subject includes administering a ganglioside preparation enriched in GM1, derived from an ovine animal afflicted with GM1 gangliosidosis. The ganglioside preparation is prepared through tissue isolation, extraction, and purification processes. The method includes the treatment of a symptom of Huntington's disease and other neurodegenerative diseases. A selective breeding method for producing a GM1 gangliosidosis-affected, scrapie-resistant ovine animal that produces substantially high tissue concentrations of GM1 ganglioside is described. A method to produce multiple successive generations of ovine animals to produce a GM1 gangliosidosis-affected, scrapie-resistant ovine animal and the production of additional generations to improve trait characteristics. The ganglioside product enriched in GM1 is extracted from an ovine animal that is GM1 affected and scrapie-resistant.
