I bred Tuli cattle for over 30 years in the harshest African conditions and exported the first Tulis to Namibia in 1978, and further groups to South Africa. The main reason Tuli cattle were not imported into the U.S.A earlier was purely political,there was certainly enough interest from top American geneticists. They are not all things to all breeders, I never recommend them for the colder,wetter, states.
For heat resistance, low maintenance,fertility and docility there is no existing commercial breed that can equal them in harsh conditions, especially as a base breed in a crossbreeding program.I will be pleased to answer specific questions on the breed.
All the best,Andy.