Effect of treatment with progesterone and oestradiol when starting treatment with an intravaginal progesterone releasing insert on ovarian follicular development and hormonal concentrations in Holstein cows

• Published in: Animal reproduction science 2003-04, Vol.76 (3), p.177-193
• Main Authors: Cavalieri, J., Hepworth, G., Parker, K.I., Wright, P.J., Macmillan, K.L.
• Format: Article
• Language: English
• Subjects: Administration, Intravaginal; Animals; Cattle - physiology; Cattle-endocrinology; Estradiol - administration & dosage; Estradiol - blood; Estrus; Estrus Synchronization; Female; Follicle Stimulating Hormone - blood; FSH LH; Hormones - blood; Luteinizing Hormone - blood; Oestrogen; Ovarian Follicle - diagnostic imaging; Ovarian Follicle - drug effects; Ovarian Follicle - physiology; Ovulation; Progesterone; Progesterone - administration & dosage; Progesterone - blood; Synchronisation; Ultrasonography; Wave emergence
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/S0378-4320(02)00260-9

Ovarian follicular development and concentrations of gonadotrophin and steroid hormones were studied in non-lactating Holstein cows following administration of progesterone (P 4) or oestradiol benzoate (ODB) at the start of treatment with an intravaginal progesterone releasing insert (IVP 4) in a 2 by 2 factorial experiment. Cows were treated at random stages of the oestrous cycle with an IVP 4 device (Day 0) and either no other treatment ( n=8), 200 mg of P 4 IM ( n=9), 2.0 mg of ODB IM ( n=8) or both P 4 and ODB ( n=9). Seven days later devices were removed and PGF 2α was administered. Twenty-four hours later 1.0 mg of ODB was administered IM. Oestrus was detected in 97.1% and ovulation in 64.7% (effect of treatment, P=0.41) of cows within 96 h of removing inserts. In the cows that ovulated, day of emergence of the ovulatory follicle was delayed ( P