Relationship between the Sperm Count and the Fertilization Rate of Ova Ovulated from the Contralateral Ovary in Intrauterine Horn Insemination in Cats

Abstract

Unilateral intrauterine horn insemination (UIUI) was carried out in cats, and we investigated the fertilization rate of ova ovulated from the contralateral ovary. Various numbers of sperm were used to inseminate the uterine horn on the side where ovulation was inhibited. The rates of conception were 1/11 (9.1%), 2/11 (18.2%), and 5/7 (71.4%) in the 2 × 10⁶, 4 × 10⁶, and 8 × 10 ⁶ groups, respectively. Furthermore, the fertilization rate was 70.7% in the 8 × 10⁶ group. Thus, ova ovulated from the contralateral ovary were not fertilized or the fertilization rate was low in some cats even when UIUI was performed with a large number of sperm.