Effect of human chorionic gonadotropin on duration of estrous cycle and fertility of normally cycling, nonlactating mares: Voss, J. L., B. W. Pickett, L. D. Burwash, and W. H. Daniels. J. Am. Vet. Med. Assoc., 165(8): 704, 1974. Departments of Clinical Sciences (Voss) and Physiology and Biophysics (Pickett and Burwash), Colorado State University, Fort Collins, and the Department of Pathology (Daniels), University of Connecticut, Storrs, CT U.S.A.