Preovulatory LH profiles of superovulated cows and progesterone concentrations at embryo recovery.
Forty-two Holstein cows were randomly assigned to three superovulatory treatment groups of 14 cows each. Cows in Group I received follicle stimulating hormone (FSH; 50 mg i.m.); those in Group II received FSH (50. mg i.m.) along with GnRH (250 ug in 2 % carboxymethylcellulose s.c.) on the day of estrus; and cows in Group III were infused FSH (49 mg) via osmotic pump implants. FSH was administered over a 5-d period for cows in Groups I and II (twice daily in declining doses). Cows in Group III received FSH over a 7-d period (constantly at a rate of 7 mg/day). All cows received 25 mg PGF(2)alpha (prostaglandin F(2)alpha) 48 hours after initiation of the FSH treatment. Blood samples were collected from seven cows from each group at 2 hour intervals on the fifth day of superovulation for serum luteinizing hormone (LH) concentration analysis by radioimmunoassay, and blood samples were collected from all cows on the day of embryo recovery for plasma progesterone determination. The LH profile was not altered (P>0.05) by either GnRH administration or by the constant infusion of FSH as compared to FSH treatment alone. Plasma progesterone concentrations were highly correlated with the number of corpora lutea (CL) palpated (r=0.92; P<0.01) and with the number of ova and/or embryos recovered (r=0.88; P<0.01). The accuracy of predicting the number of recoverable ova and/or embryos by the concentration of plasma progesterone was 86%.
Wubishet
A
A
Department of Animal Sciences University of Illinois Urbana, IL 61801 USA.
Kesler
D J
DJ
Graves
C N
CN
Spahr
S L
SL
Favero
R J
RJ