Plasma LH and Progesterone Levels before and after Ovulation and Observation of Ovarian Follicles by Ultrasonographic Diagnosis System in Dogs.

Abstract

. Recently, canine frozen semen has been attracting attention for breeding purposes, and methods of judging ovulation and optimum timing for insemination have become important. As methods of predicting the canine ovulation, vaginal smear, plasma sex hormone levels and ultrasonographic diagnosis system (US) have been investigated in combination, but a standard technique has not yet been established. Therefore, we investigated a method of predicting canine ovulation in dogs by US, and by measuring plasma LH and progesterone (P) levels three times a day. Ovulation could be observed by detecting irregularly shaped ovarian follicles by US in six of 11 dogs (54.5%). In these dogs, the time between the LH peak and ovulation was 24-48 hr, 38.0 hr on average. The P level on the ovulation day was 1.88-2.81 ng/ml, 2.34 ng/ml on average. A value of 1.88 ng/ml was detected in one dog, but the other five dogs showed P levels of 2 ng/ml or higher. The P level on the day before ovulation was 0.8-1.56 ng/ml, 1.12 ng/ml on average. Assuming that ovulation occurred two days after the LH peak in the 11 experimental dogs, the P level was 2.12-4.06 ng/ml, 2.78 ng/ml on average. The period of a high LH level, not less than 10 ng/ml, continued for 12 hr around the LH peak. Based on these findings, to predict ovulation using US and LH level, it would be necessary for the tests to be performed several times a day. In contrast, it was shown that the day on which a plasma P level of 2 ng/ml or higher was detected by the test performed once a day corresponded to the ovulation day.-KEY WORDS: canine, LH, ovulation, progesterone, ultrasonography.J. Vet. Med. Sci. 62(3): 243-248, 2000 determining the ovulation is difficult, and a technique to predict accurately ovulation in dogs has not yet been established. In this study, therefore, we investigated a method of predicting the ovulation in dogs by thrice daily observation by US and thrice daily measurement of blood LH and P levels. Since the mating period in dogs is 3-5 days after ovulation [17,18,20], a method of predicting the ovulation during the mating period was investigated. MATERIALS AND METHODSExperimental animals: Eleven in-bred beagle dogs aged 2 to 5 years maintained at Nippon Veterinary and Animal Science University were used in the experiments. These dogs were known to be reproductively normal from previous estrous cycles and consisted of nine multiparous dogs and two nulliparous dogs. The dogs were maintained in cages measuring 160 × 75 × 65 cm and were fed commercial dog foods once a day. The dogs were given drinking water three times a day, in the morning, afternoon and evening.Observation of estrus: The female dogs were observed every day for pudendal enlargement and the presence or absence of vulval bleeding.Blood collection for hormone measurements: Blood samples for measurements of plasma LH and P levels were collected once a day (19:00) between the first day of vulval bleeding and the first day on which ovarian follicles could be observed by US, then collected t...

Artificial Insemination of Frozen Epididymal Sperm in Beagle Dogs

“…The semen volume infused was about 200 µl at the tube bottom after centrifuging thawed semen at 1,500 rpm for 5 min. Artificial insemination was performed during the optimal mating period 3-5 days after ovulation, estimated from the peripheral blood progesterone level as reported previously [3].…”

Intrauterine and Intravaginal Insemination with Frozen Canine Semen Using an Extender Consisting of Orvus ES Paste-Supplemented Egg Yolk Tris-Fructose Citrate

“…three or four days after the ovulation day predicted from the peripheral plasma progesterone level [5]. The semen used for AI had been kept frozen for from 1 to 15 months.…”

“…AI: As previously reported [5], AI was performed during the optimal mating period, i.e. three or four days after the ovulation day predicted from the peripheral plasma progesterone level [5].…”

“…OEP was added to a final concentration of 0.75% (v/v). For straws, 1.0 ml straws were used, and the sperm concentration was adjusted to 1 × 10 8 /ml, and frozen using a conventional freezer.AI: As previously reported [5], AI was performed during the optimal mating period, i.e. three or four days after the ovulation day predicted from the peripheral plasma progesterone level [5].…”

Fenprostalene-induced Abortion in Bitches.

“…Peripheral blood was collected from the dogs presenting signs of estrus once daily from the 6th day after the onset of estrous bleeding, as we previously reported, and the onset of ovulation was timed from peripheral blood P 4 levels [4]; the first day that a peripheral P 4 level of 2 ng/ml or over was recorded was regarded as the day of ovulation. The female dogs were mated once with male dogs during the 3-day period after ovulation that is suitable for mating, and were observed for conception.…”