Effect of repeated eCG treatments and ovum pick-up on ovarian response and oocyte recovery during early pregnancy in suckling beef cows

• Published in: Animal reproduction science 2012-07, Vol.133 (1-2), p.10-15
• Main Authors: Aller, J.F., Mucci, N.C., Kaiser, G.G., Callejas, S.S., Alberio, R.H.
• Format: Article
• Language: English
• Subjects: Angus; animal ovaries; Animals; Animals, Suckling; artificial insemination; beef cows; Cattle; Chorionic Gonadotropin - administration & dosage; Chorionic Gonadotropin - pharmacology; Drug Administration Schedule; Early pregnancy; eCG; equine chorionic gonadotropin; Female; Fertility Agents, Female - administration & dosage; Fertility Agents, Female - pharmacology; Gestational Age; Gonadotropins, Equine - administration & dosage; Gonadotropins, Equine - pharmacology; in vitro fertilization; Oocyte; Oocyte Retrieval - methods; oocytes; Oocytes - drug effects; Oocytes - physiology; Ovary - drug effects; Ovary - physiology; Ovulation Induction - methods; Ovulation Induction - veterinary; Ovum - drug effects; Ovum pick-up; Pregnancy; pregnancy outcome; Pregnancy, Animal - drug effects; suckling
• ISSN: 0378-4320; 1873-2232
• DOI: 10.1016/j.anireprosci.2012.06.001

This study was designed to evaluate in suckling early pregnant beef cows with and without eCG-pre-stimulation: (i) the influence of day gestation (from 40 to 101 days) and the consecutive eCG treatments on the follicular growth induced by means of ultrasound-guided transvaginal follicle ablation (FA; all follicles≥5mm) and the number and quality oocytes recovered by ovum pick-up (OPU) and (ii) the possible effects of repeated hormonal stimulation and FA/OPU on pregnancy outcome. Twelve suckling early pregnant Angus cows (40 days post fixed-time artificial insemination) were randomly assigned to each of two groups (n=6group−1). Group 1 treatments included: FA (Day 0), eCG (1600IU; Day 1) and OPU (Day 5). Group 2: as cited Group 1 with no eCG treatment. In both groups, OPU was repeated five times (Days 45, 59, 73, 87 and 101 of gestation). The numbers (mean±SEM) of class II (5–9mm; 4.3±0.9) and class III (≥10mm; 2.5±0.4) follicles visualized per cow per OPU session in eCG-treated cows were greater (P