Fertility of dairy cattle following oestrus and ovulation controlled with cloprostenol, oestradiol benzoate and progesterone or progesterone and cloprostenol

Effect of Follicular Aspiration at the Onset of Progesterone-based Timed Artificial Insemination on the Follicular Dynamics and Fertility of Early Postpartum Japanese Black Cows

“…One of the key points in designing these protocols is how to control follicular growth. Options to control follicular growth include administration of progesterone, estradiol-17β or gonadotropinreleasing hormone (GnRH) [4][5][6][7][8][9][10][11][12][13] and ultrasound-guided transvaginal follicle ablation [14,15]. While progesterone inhibits ovulation of a dominant follicle, it allows the dominant follicle to maintain dominance, leading to low fertility due to an aged ovum being maintained for an extended period in a high-progesterone environment [4,16].…”

“…First, it instantly eliminates the dominant follicle(s) to guarantee new follicular wave emergence [14]. Second, it enables the collection of immature ova that could be used to produce transferable embryos by in vitro fertilization (IVF), which would increase the genetic resources available for a Japanese Black cattle breeding program [23].Use of progesterone in TAI would increase the rate of ovulation synchronization [4][5][6][7][8][9] and conception rates [9][10][11][12][13] by controlling follicular growth. We previously obtained a high conception rate using a TAI protocol with progesterone and follicular aspiration on suckled or nonsuckled Japanese Black cows as early as 30 days postpartum [23,24].…”