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[Follicle dynamics and characteristics of ovulation in heifers after Ovsynch treatment in the last third of the estrous cycle].

The objective of the experiment was to study follicular dynamics and characteristics of ovulations in dairy heifers after application of the Ovsynch protocol in the last third of estrous cycle. Therefore, altogether 27 regular cycling Holstein heifers were given an injection of GnRH on day 14, 16 or 18 (9 heifers each in group 1 to 3) of the estrous cycle. All heifers were administered PGF2alpha seven days later. Blood was collected for progesterone determination, just before, 24 hours and 48 hours after the PGF2alpha injection. A second injection of GnRH was administered 48 hours after the PGF2alpha injection. Ovarian follicular dynamics were monitored by frequent ultrasound scanning of the ovaries after first and second GnRH injection. Altogether 22 of 27 heifers (81.5%) ovulated 27 to 33 h after first GnRH injection. In 4 heifers ovulations were recorded 45 to 51 h after first GnRH application. Mean intervals between GnRH application and ovulation were 33.0, 33.6 and 28.3 h, respectively. At the time of PGF2alpha injection mean progesterone concentrations were similar in groups 1 and 2, but significantly lower than in group 3. After the second GnRH treatment 5,6 and 8 heifers had ovulations. The average intervals from the second GnRH treatment to ovulation were 24.8, 24.0 and 24.4 h respectively. The results show that Ovsynch is not sufficient to ensure synchronisation of oestrous and ovulation in each animal treated.

Animals↗
PubMed1991

Effect of a prostaglandin F2 alpha analogue prostinfenem (15-methyl-PGF2 alpha), to induce luteolysis and oestrus in heifers.

Different doses of 15-methyl-PGF2 alpha (0.125-10 mg) were used to induce luteolysis and oestrus in 7 heifers with 28 treatments on day 8-12 of the oestrous cycle. Twenty-three out of 28 treatments gave the desired response and the animals showed signs of oestrus within 5 days post-injection. The doses of 0.25-10 mg can be used to induce luteolysis and oestrus. The dose of 0.125 mg was not effective to induce luteolysis and only 1 out of 4 treatments responded. When higher doses were given (1-10 mg), progesterone levels decreased more rapidly and reached 1 nmol/l 16.2 h earlier than in animals which responded to doses less than 1 mg. The minimum effective dose was considered to be 0.25 mg. Clinical signs of oestrus, regression of corpus luteum and variation in the interval to oestrus were similar as for PGF2 alpha or its other analogues. By measurement of the main circulating prostaglandin F2 alpha metabolite, it was found that an endogenous PGF2 alpha release occurred 1-3 days post-injection of 15-methyl-PGF2 alpha. Furthermore in cases of post-oestrous bleedings an endogenous PGF2 alpha release was also seen concomitantly with the bleeding. This prostaglandin analogue seems to be useful for farm management and can be an alternative to other PGF2 alpha analogues.

Animals↗
PubMed1990

Treatment of anoestrous mares with a synthetic progestagen, allyloestrenol.

Anoestrous mares were treated with prostaglandin (n = 43) and those that did not respond to prostaglandin (n = 29) with a synthetic progestagen, allyloestrenol, at a dose of 0.05 mg/kg body mass for 12 days. After the cessation of the long-term per os gestagen blockade the animals were checked for heat and, if a preovulatory follicle could be palpated, 2000 IU hCG was administered to induce ovulation. In some animals the plasma 17 beta-oestradiol (E2) and progesterone (P4) levels were also followed up throughout the gestagen treatment and for 10-14 days thereafter. As the favourable oestrus rate (86.2%) and pregnancy rate (65.5%) indicate, the 12-day allyloestrenol treatment seems to be a reliable tool for induction of cycling in mares anoestrous early in the season. These results, supported by the E2 and P4 profiles, suggest that an important reason for anoestrus in mares is the absence of a functional corpus luteum that can be substituted for by exogenous gestagen administration. The timing of ovulation, however, should still be improved.

Allylestrenol↗
PubMed1990

[The effect of the day of parturition in the technological cycle of maternity on the morbidity of diarrhea in lactating piglets].

The study investigated the frequency of piglet diarrhoea from birth to weaning (33rd day) in a farrowing pigsty with 3 rows of boxes during 7 rearing cycles with 240 piglets each, always related to the day of birth in connection with the onset of the cycle. 3 groups were differentiated according to the day of birth: 3 and 4, 5, 6 and 7, based on the disposition of the sow. Also investigated was the position of the litters in the middle or one of the marginal rows of boxes of the pigsty. The germ density of the air during 2 cycles each of the rainy and dry seasons was investigated in the empty pigsty as well as after the 6th day of occupation by means of sedimentation in endo agar. A significant influence was found of the day birth (p less than 0.05) and of the interaction of row of boxes and day of birth (p less than 0.05) as well as the row of boxes and season (p less than 0.05) on the morbidity and mortality due to piglet diarrhoea. The higher levels occurred in the groups of animals born later and housed in the central row of boxes. The number of units forming colonies increased significantly (p less than 0.05) in 10 cm2/min samples on endo agar from the 0th to the 6th day of the cycle and reached 100% of the samples from which also E. coli K 88 was isolated.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Folliculogenesis and embryo transfer in ruminants].

In ruminant embryo transfer development, the limiting step remains the superovulation of the donor: using both PMSG and pituitary extracts, the superovulatory response is variable. In our research unit, FSH and LH were purified until homogeneity. Superovulatory treatment includes the administration of pure FSH the day following the preovulatory LH pulse and an administration of an LH/FSH mixture in the middle cycle. This biphasic stimulation of folliculogenesis allows superovulatory response with more and higher quality embryos.

Animals↗
PubMed1989

[The course of ovulation in gilts after the partial replacement of HCG by GnRH for ovulation stimulation].

The ovulation status and the amount of ovulated follicles were determined in 3 experiments from 197 gilts which had been given differentiated treatment and which were subsequently slaughtered. Ovulation stimulation produced high synchronisation effects, as compared to untreated animals. Partial substitution proved possible of Gn-RH vet. "Berlin-Chemie" for 500 I.U. of HCG which were generally used to stimulate ovulation, since the amount of ovulated follicles 169 hours from the last application of Suisynchron premix was in all 3 cases above the specified value of 85.0 per cent even after injection of 300 I.U. HCG/300 micrograms Gn-RH.

Animals↗
PubMed1989

[Embryo transfer in swine in relation to a gene transfer program].

The production of the recommended embryonic stage for microinjection of foreign DNA into pronuclei needs a precisely timed preparation of donor pigs. For oestrus induction 1250 IU of PMSG is used at a body weight of 60 kg to 90 kg. To induce ovulation 750 IU of HCG are injected 3 days later. After two inseminations eggs are collected by surgical flush of the oviducts and centrifuged for 3 min at 15,000 g for visualization of the pronuclei. After DNA-microinjection the embryos are transferred to 12 h asynchronous recipients. About 50% of the collected eggs could be used for our experiments. The number and quality of the recovered eggs was related to the body weight of the donors. An in vivo culture system in the non-ligated pig oviduct was established in order to measure the effects of the distinct steps in microinjection on embryo survival. The survival rate of untreated zygotes was 52%. After centrifugation the rate was reduced to 38% and after microinjection to 12%. Pregnancy rate after 98 transfers was 37% and an average of 3.9 piglets were born per litter.

Animals↗
PubMed1989

Transcervical embryo transfer in performance mares.

Pregnancy was established by transcervical transfer of embryos from performance mares into recipient mares. Estrus was synchronized between donor (n = 17) and recipient (n = 43) mares. After a greater than or equal to 25-mm follicle was detected, donor mares were bred artificially daily until ovulation. Day of ovulation was recorded. Uterine flushes (n = 111) were performed on donor mares 7 days after ovulation, and recovered embryos were transferred transcervically to recipient mares within 2 hours. Embryos were recovered from 40.5% of uterine flushes. Of transferred single embryos, 65.7% resulted in pregnancy, detectable by ultrasonographic examination 23 days after transfer. Only 35.3% of twin embryos resulted in pregnancy. Results over a 4-year period were as follows: uteri were flushed on 14, 44, 31 and 22 occasions, and 8, 21, 15, and 11 embryos were recovered (1 embryo was not transferred), with 6, 11, 4, and 6 resulting in 30-day pregnancy in years 1 to 4, respectively.

Animals↗
PubMed1989

[The appearance of ovarian cysts in young sows after treatment with gonadotropin preparations for estrus induction].

In 72 (46%) of 155 gilts discarded for genetic reasons after performance testing and housed under fattening conditions no heat could have been detected during the first 30 days. The gilts were assigned alternatingly to a control group and four different treatments of delayed puberty. The induction of puberty was carried out by injections of 1000 iu PMSG, 400 iu HCG and 2 mg oestradiol benzoate, 400 iu PMSG and 200 iu HCG and 800 iu PMSG and 400 iu HCG. If there was no estrus gilts were slaughtered 12 days later for examination of the ovaries. Those coming into estrus were slaughtered 8 days after disappearance of estrus. Estrus could be induced in 69 to 94% of the gilts, whereas 40% of the untreated showed estrus signs. After treatment with PMSG and HCG in 40 and 87% of the gilts cysts were found whereas none of the untreated and 26 and 29% of those treated with PMSG und HCG + oestradiol benzoate revealed ovarian cysts. In addition, those gilts that had come into estrus during the first 30 days were given injections of either 1000 iu PMSG or 800 iu PMSG and 400 iu HCG. The injections were made either on the 5th, 10th or 15th day of cycle. In both latter groups significantly more gilts showed standing heat than after treatment at cycle day 5. The results of inspection of the ovaries at slaughter and steroid hormones could not be assigned to a defined stage of the physiological ovarian cycle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Use of pulsatile intravenous administration of gonadotropin-releasing hormone to induce fertile estrus in bitches.

The pulsatile IV administration of gonadotropin-releasing hormone (GnRH) was evaluated as a method to induce fertile estrus in 8 anestrous Beagle bitches. Bitches received 1.25 micrograms of GnRH every 90 minutes for 11 to 13 days. Gonadotropin-releasing hormone was delivered by use of an automatic pump. Reproductive history was known for all bitches, 4 of which, on the basis of 3 or 4 preceding cycles, had an interestrous interval of 219 +/- 14 days (mean +/- SEM). Estrus induction was attempted during early anestrus in 6 bitches (ie, 148 +/- 10 days since the preceding estrus) and late anestrus in 1 bitch (ie, 260 days since the preceding estrus); another bitch had not had an estrous cycle for nearly 2 years before GnRH administration. Signs of estrus were seen within 16 days after the start of GnRH administration in the bitches with regular estrous cycles (group 1, n = 7), and within 23 days in the bitch (group 2) with prolonged anestrus. All bitches were bred, and 7 of 8 (87.5%) became pregnant, with a mean litter size of 4.5 +/- 0.75. A normal hormonal response pattern was observed in group-1 bitches--a peak increase in plasma estrogen concentration of 22.3 +/- 2 pg/ml immediately before the onset of estrus. Peak plasma progesterone concentration (17.3 +/- 3 ng/ml) was observed 1 to 14 days after the onset of diestrus in the group-1 bitches that ovulated, and adequate plasma progesterone concentration was maintained throughout gestation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

[Superovulation induction in buffalo cows (Bubalus bubalis) with follicle-stimulating hormone (FSH)].

A total of 19 buffalo cows were used to induce superovulation following a pattern that included the use of FSH at the rate of 40 mg in the course of four days, applied twice a day and of Oestrophan at 48 hours after the beginning of treatment. Fifteen animals manifested estrus and were twice inseminated. The superovulation response of the ovaries was 4.3 +/- 0.8 yellow bodies and 0.5 +/- 0.24 follicles greater than 8 mm. A nonsurgical method was employed to obtain 24 embryos of high quality and an unfertilized ovum from 8 buffalo cows.

Animals↗