Segmental hypoplasia of the right horn of the uterus has led to the inspissation of the trapped uterine secretions. The mass subsequently broke up into smaller fragments, called hysteroliths or uterine stones. This cow cycled normally; notice CL on the left ovary. A follicle is present on the right ovary. Ovulation from the ovary ipsilateral to the incomplete horn would lead to a persistent CL due to the lack of prostaglandin F2alpha.
Roberts SJ (1973)