Effect of repeated eCG treatments and ovum pick-up on ovarian response and oocyte recovery during early pregnancy in suckling beef cows.
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 ≥ 5 mm) 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=6 group(-1)). Group 1 treatments included: FA (Day 0), eCG (1600 IU; 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 (5-9 mm; 4.3 ± 0.9) and class III (≥10 mm; 2.5 ± 0.4) follicles visualized per cow per OPU session in eCG-treated cows were greater (P<0.05) than for non-treated cows (0.9 ± 0.1 and 0.9 ± 0.1, respectively). In contrast, the number (mean ± SEM) of class I (<5mm) follicles per cow per OPU session was lower for cows with eCG treatment (2.8 ± 0.4) than for non-treated cows (5.7 ± 0.5). The mean number of aspirated follicles was not significantly different (P<0.05) between eCG-treated cows and non-treated cows at 45 and 59 days of pregnancy. However, the mean number of aspirated follicles was greater (P=0.03) in eCG-treated cows than non-treated cows from 73 day of pregnancy onwards. The numbers (mean ± SEM) of recovered oocytes and viable oocytes/cow/session were greater (P<0.05) for eCG-treated cows (2.2 ± 0.2 and 1.6 ± 0.4, respectively) than for non-treated cows (1.0 ± 0.2 and 0.9 ± 0.2, respectively). No donor pregnancies were lost either during or following OPU procedure. We can conclude that (1) eCG-treated pregnant suckled cows can be a source of oocytes for IVF at least to 100 days of gestation and (2) repeated FA/eCG treatment/OPU procedures did not affect the pregnancy outcome.
Biotecnología de la Reproducción, Estación Experimental Agropecuaria Balcarce, Instituto Nacional de Tecnología Agropecuaria, Argentina. jaller@balcarce.inta.gov.ar
J F
JF
Aller
N C
NC
Mucci
G G
GG
Kaiser
S S
SS
Callejas
R H
RH
Alberio
D000818:Animals; D000833:Animals, Suckling; D002417:Cattle; D006063:Chorionic Gonadotropin / Q000008:administration & dosage / Q000494:pharmacology; D004334:Drug Administration Schedule; D005260:Female; D005300:Fertility Agents, Female / Q000008:administration & dosage / Q000494:pharmacology; D005865:Gestational Age; D006064:Gonadotropins, Equine / Q000008:administration & dosage / Q000494:pharmacology*; D054315:Oocyte Retrieval / Q000379:methods; D009865:Oocytes / Q000187:drug effects* / Q000502:physiology; D010053:Ovary / Q000187:drug effects* / Q000502:physiology; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary; D010063:Ovum / Q000187:drug effects; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects
D006063:Chorionic Gonadotropin; D005300:Fertility Agents, Female; D006064:Gonadotropins, Equine