Fertility Associated Antigen in Peripubertal Beef Bulls as an Indicator of Potential Fertility

Fertility Associated Antigen in Peripubertal Beef Bulls as an Indicator of Potential Fertility. (August 2005) Joanna Lynn Gallino, B.S., California State Polytechnic University Co-Chairs of Advisory Committee: Dr. L. R. Sprott Dr. D. W. Forrest Ejaculates from peripubertal Angus (n=106), Brahman (n=156) and Brangus (n=212) bulls were evaluated for the presence of a 31 kDa protein known as fertility associated antigen (FAA) using the ReproTest for Bulls (ReproTech, Tucson, AZ). This study was designed to test the repeatability of FAA detection using the chute-side cassette and to quantify the relationship of age, scrotal circumference, sperm motility, ejaculate volume and sperm concentration with the presence of FAA in ejaculates from peripubertal bulls. A total of 776 ejaculates were collected, and 77% (n=598) were classified as FAA. Three ejaculates were obtained from 133 bulls (Angus, n=33; Brahman, n=100) on d 0, 30 and 60. Brahman bulls were older (p<0.0001) at puberty than Angus bulls. Ejaculate volume was the only trait that differed between bulls that were classified as FAA and FAA at first collection. Mean ejaculate volume was greater (p<0.0001) for FAA than for FAA ejaculates. Serial ejaculates were profiled according to one of four FAA classification patterns (0 = three FAA ejaculates; 1 = three FAA ejaculates; 2 = first ejaculate FAA; and 3 = first ejaculate FAA). A majority of the bulls were FAA on all three ejaculates (57%) or at least on the first