LH DETECT® is an ELISA sandwich type immunoenzymatic test. The enzymatic activity is revealed by a chromogenic substrate.

Reaction intensity is proportionnal to LH concentration in the test sample. They evaluation may be performed visually (qualitative) or measured with a spectrophotometer.

For qualitative assay, a positive control sample permits the reaction validation. For this use, we recommend using ABTS as substrate.

For quantitative assay, a scale of standards, produced with the LH of the concerning specie, is used. In this case, we recommend using TMB as substrate.

You can choose between two types of plate: entire one, or strip one divisible in 16-well segments. The strip one allows avoiding defrosting all the wells when only a few samples are going to be tested.

LH DETECT® can be used for the following works:

• Accurate and quantitative study of LH secretions micropulsatility: take a sample every 15 minutes during a 10 hours period (Khireddine et al., 1998).

• Preovulatory LH surge detection among cows after œstrus and ovulation synchronization treatment (CRESTAR) :

  Two protocols have been described :

  • Measurement from blood samples taken every hour, from 29 h to 49 h after implant withdrawal (Khireddine et al., 1998).

  • œstrus detection every 4 hours from implant withdrawal, and LH measurement from blood samples taken every 4 hours, for 24 hours as from the certified œstrus appearance. For females with a delayed œstrus, blood sampling continues until 72 hours after implant withdrawal (Culardes cows) (Maurel et al., 1994b).

  • The same kind of sampling protocol can be realised after œstrus detection in the case of artificial insemination realized after natural heats.

• Preovulatory LH surge detection among heifers after superovulation treatment :
  

  Two protocols have been described :

  • After œstrus pre-synchronization, Culards cows receive 8 injections of porcine FSH (Stimufol). The LH surge is detected from blood samples taken every 3 hours, during a 42 hours period from the last FSH injection to the second artificial insemination (Maurel et al., 1994a).

  • After œstrus pre-synchronization, females (Charolaises cows) receive a FSH treatment (Stimufol). LH surge detection is done on blood samples taken 24 hours after CIDR-B treatment (experimental lot), or 12 hours after prostaglandin injection (control lot). Those injections are done every 3 hours for 36 hours (Lafri et al., 2002).