Prediction of bovine ovulation by a rapid radioimmunoassay for plasma LH

Abstract

Summary. A commonly used and specific plasma LH radioimmunoassay was modified to provide reliable results for cow LH concentrations in blood within 4\p=n-\5h. Blood samples were collected at 2-or 4-h intervals from at least 24 h before the expected oestrus until after its onset. Thereafter, samples were collected at intervals of 2 or 4 days until the next oestrus. For the assay, the antigen\p=n-\antibody reaction took place during a 2-h incubation at 37\s=deg\C.The immune complex was precipitated by addition of rabbit anti-\g=g\-globulin and polyethylene glycol followed by an incubation at 22\s=deg\Cfor 30 min. The coefficient of variation between this assay and the standard assay was <15%. From a study of 25 cycles from 12 animals, we obtained intervals of \ m=si meq\ 27\m=.\3h between the beginning of the LH peak and ovulation and \ m=si meq\ 17\m=.\5h between the end of the peak and ovulation. This modified technique can be used to predict rapidly and precisely the time of ovulation in cattle.

Differentially Expressed Candidate miRNAs of Day 16 Bovine Embryos on the Regulation of Pregnancy Establishment in Dairy Cows

“…The cows were inseminated 12 h after the first sign of standing estrus. It should be noted that ovulation occurs approximately 30 h after standing estrus can first be observed [20,21]. The embryos were recovered using the non-surgical uterine flush technique on day 16 after insemination.…”

A rapid radioimmunoassay for determining plasma concentrations of LH in dogs

“…One possible way to establish a rapid LH radioimmunoassay would be to shorten the incubation time and improve the separation system. Bernard et al (1983) In the normal incubation assay ovine LH antiserum was diluted 1:150000. Overnight incubation, including a 2-h delay in the addition of 125I-labelled sheep LH, was carried out at room temperature.…”