from
http://redangus.org/registration/breeders-guide
RED ANGUS ASSOCIATION CATEGORIES
There are 4 Categories in the Red Angus Association of America:
• Category 1A
• Category 1B
• Category II
• Category III
WHAT IS REQUIRED FOR REGISTRATION IN EACH OF THESE CATEGORIES?
• Category 1A
To be eligible for Category 1A registration, calves must be 100 percent Red
Angus. The calf must be solid red in color and polled with no disqualifying
characteristics (See Rules and Regulations, Section C). Birthdate, permanent
tattoo, and actual weaning weight and date weighed are required.
• Category 1B
To be eligible for Category 1B registration, calves must be from 87 percent to
and including less than 100 percent Red Angus and the parents must be
registered. The calf must be solid red in color and polled with no
disqualifying characteristics (See Rules and Regulations, Section C). Birth
date, permanent tattoo, and actual weaning weight and date weighed are
required.
• Category II
To be eligible for Category II, calves must be equal to or greater than 87% up
to and including 100% Angus blood content having one or more disqualifying
characteristics. (See Rules and Regulations, Section C).
• Category III
Calves that are less than 87% Angus blood content. (See Rules and
Regulations, Section C).
from the ASA
http://www.shorthorn.org/opportunities/durhamred/durhamred_opportunities.html
The Durham Red breed composition will consist of no less than 25 percent and up to 75 percent Shorthorn blood with the remainder coming from Red Angus. The parents must be registered with the American Shorthorn Association or the Red Angus Association of America.
The program does not allow for blood from a third breed or of unknown breed composition. Breeders can strive for either more Shorthorn parentage or more Red Angus parentage utilizing a multitude of crossbreeding strategies to optimize characteristics from either breed
My read is must be 1A RA and 100% Shorthorn