Effect of injecting collagenase into the uterine artery during a caesarean section on the placental separation of cows induced to calve with dexamethasone.

A caesarean section was performed on 30 cows before normal term and 16 to 20 hours after the induction of parturition with dexamethasone. During the surgical procedure, 20,000 U of bacterial collagenase was injected into the uterine artery of 15 of the cows. The average periods of retention of the fetal membranes were 40 hours in the treated cows and 114 hours in the control cows (P<0.

Influence of CIDR treatment during superovulation on embryo production and hormonal patterns in cattle.

One of the major sources of success in embryo transfer is timing of AI relative to the LH surge and ovulation. The aim of this study was to compare the embryo production following superovulation during a PGF2alpha (control cycle) or a CIDR-B synchronized cycle (CIDR-B cycle). CIDR-B (CIDR-B ND, Virbac, Carros, France) was inserted on Day 11 of a previously synchronized cycle and left for 5 days.

Use of an immunoenzymatic assay to detect the luteinizing hormone peak in bitches.

The success of artificial insemination with fresh chilled or frozen semen depends on the time of insemination. Determination of oestrous behaviour, use of vaginal smears or measurement of the vaginal resistivity are unreliable techniques and interpretation of the dosages of progesterone may be critical as it may vary from one laboratory to another. The plasma concentration of LH displays a peak of secretion that can be a good reference to date the events of the ovarian cycle.

Fertilization time in the bitch in relation to plasma concentration of oestradiol, progesterone and luteinizing hormone and vaginal smears.

Seven bitches of several breeds were monitored during oestrus by vaginal smears and luteinizing hormone (LH), oestradiol and progesterone plasma assays. Each bitch was inseminated into the uterus with frozen spermatozoa from seven dogs of different breeds. Each female was inseminated daily with about 200 x 10(6) motile spermatozoa.