PMSG dosage precision in young and old sows in the course of biotechnical ovulation synchronization. 3. Fertility and litter effects

One single PMSG batch, Pregmagon-Dessau, was compared with other PMSG doses on 2,126 adult sows and 1,700 gilts from five farms. Additional comparisons were made with other Pregmagon or Prolosan batches on 1,178 adult sows and 1,026 gilts. All experiments were made in the context of a programme for ovulation synchronisation and term-oriented insemination. Doses of 700, 800, 900, and 1,000 IU were tested on adult sows and 600, 800, and 1,00 on gilts, with the mean dose of 800IU being found to be sufficient or superior to other doses for fertility results. Doses for adult sows could be adjusted and related to present and previous litter numbers, with the dosage being between 700IU (treatment for third litter) and 700 to 800IU (treatment following average to high previous litter. The preferential dose for gilts was found to be 800IU. Higher PMSG doses (up to 1,000IU) should not be used in synchronisation of ovulation and term-oriented insemination unless extraordinary conditions were safely established.     

The dose precision of PMSG for gilts and old sows in procedures for ovulation synchronization. 2. Organometric and histometric findings after diagnostic slaughtering

An account is given in this paper of organometric and histometric findings obtained, on three farms, N, B, and D, from ovaries, uteri, and oviducts of biotechnologically treated gilts and adult sows, using differentiated PMSG doses (600, 800, and 1,000 IU on gilts and adult sows of N and B; 500, 1,000, and 1,500 IU on gilts of D). Ovulation potentials were within the biological normal in response to low dosage (with an average of 12 to 15 follicles in gilts and 17 in adult sows). The 800 IU dose caused significant stimulation, which had to be interpreted as overstimulation for PMSG-sensitive probands of N. Ovarian reaction and induced cycle should by duly considered for interpretation of histometric findings.     

Experimental studies on the stimulation of prenatal development in swine by PMSG treatment in early pregnancy. 1. Clinical results of embryonic development in young slaughtered sows and litter results in young and old sows after PMSG treatment on the 11th day of pregnancy

Thirty-eight gilts were slaughtered on the 25th and 39th days of pregnancy, after they had received 400 I.U. PMSG treatment on the eleventh day of pregnancy. Treated and untreated animals in a group of 140 gilts and 195 adult sows were compared with each other for post-farrowing fertility performance. Weight development of embryos obtained from the slaughtered sows depended on the number of embryos alive. The survival rate of embryos from treated sows was about 5% higher than that recorded from untreated animals. Clearly increased litter sizes which, however, were associated with lower piglet birth weights were recorded from farrowing gilts and adult sows, following PMSG treatment. The conclusion is drawn that PMSG treatment, via luteotrophic action of luteinising hormone, is capable of stabilising pregnancy-related corpora lutei, resulting in higher litter sizes. Further studies will be necessary, and emphasis will have to be laid on the problem of weight development of newborn piglets, following litter-size boosting treatment.     

Attempts at biotechnical induction of puberty in young female pigs. 2. Effects of various time intervals between one puberty induction with PMS and HCG to the following estrus synchronization on estrus and ovulation in animals about 190 days old

A biological engineering approach to induce puberty in 125 young female fattening pigs aged 190 days was undertaken on the basis of a mixture of 500 IU PMS (Prolosanserum, Dessau) with 250 IU HCG (Gonabion, Dresden). The injections were made subcutaneously. Pronounced oestrus symptoms were recorded from the external genital organs of 80% of the probands up to ten days after injection, associated with toleration in 52.8% of them. Toleration usually started on the fourth to sixth days after injection. Cycles began to develop in 57.1% up to the next oestrus period. Animals with -/x weight increase per die of 400 g exhibited lower responses. Results in terms of heat and ovulation were lower along with shorter intervals, when oestric synchronisation was undertaken 53, 32, and 17 days after the induction of puberty (20 days Suisynchron, Bernburg; 750 IU PMS).     

Comparison of the effectiveness of ovulation synchronization protocol in anestrous and cycling beef cows

Applicability of ovulation synchronization protocol using GnRH and PGF(2alpha) (PGF) injection to anestrous beef cows remains controversial. We compared the effectiveness of the protocol in the anestrous stage of the beef cow with that in the cycling stage using the same animals. Ovaries of five Japanese Black and three Japanese Shorthorn cows were ultrasonographically examined, and blood samples were collected daily for hormonal analyses. Each animal received the protocol twice (Day -6 to -8: GnRH, Day 0: PGF, Day 2: GnRH). Additional blood samples were taken before and after GnRH injection for LH and FSH measurements to evaluate the pituitary function. For the ovarian status at the onset of the protocol cows were divided into anestrous (n=8) and cycling (n=8) stages. There was no significant difference in size of the dominant follicle at the first and second GnRH injections, and in the magnitude of the pituitary response to GnRH between the two stages. However, the size of the corpus luteum and progesterone concentrations at the PGF injection in the anestrous stage were significantly smaller and lower (P<0.01), respectively, and ovulation synchronization rate in the anestrous stage was significantly lower (P<0.05) than in the cycling stage. In conclusion, ovulation synchronization protocol in anestrous beef cows has limited effectiveness.     

Experimental studies on the stimulation of prenatal development in swine by PMSG treatment in early pregnancy. 2. Analytic studies of hormones in young sows after PMSG treatment on the 11th day of pregnancy

Tens gilts received 400 I.U. of Pregmagon on the 11th day of pregnancy (day of KB2 = 1 day of pregnancy), while 8 sows were used as controls. Blood was sampled 4 times a day between the 11th and 25th day of pregnancy, with an indwelling catheter being used. Progesterone, oestradiol-17 beta, and luteinising hormone were radio-immunologically determined. The hormone profiles of pregnant sows were found to differ unambiguously from those of non-pregnant animals for both concentrations and frequencies. They were indicative of close correlations and time links of gonadotrophic and steroid hormones in early pregnancy and in oestrus. PMSG treatment in pregnancy resulted in increase in the oestradiol-17 beta concentration and attenuation in pulsatile luteinising hormone release at the time of implantation. Progesterone concentrations in peripheral blood were not affected by PMSG injection.     

Control of fertility outcome in artificially inseminated gilts and old sows. 1: Electric stimulation of estrous sows. Its effect on insemination results

Fifty gilts and 33 old sows which exhibited oestrous after bio-engineering treatment were electrically stimulated during insemination, using an A.C. mains-connected unit. The average voltages applied were 3.7 volt for gilts and between 2.5 and 2.8 volt for the old sows. The current was applied rectally, and the responsiveness differed individually. The treated animals then were compared to unstimulated controls, and the achievement in terms of born piglets was 1.18 more for gilts and 1.20 more for the old sows. Those better results were attributed to electric acceleration of sperm transport.     

Orientation studies of ovulation release in mice to test gonadotropic preparations. 2. FSH, PMSG and Gn-RH activity

The doses of FSH (follicle-stimulating hormone), PMSG (pregnant mare serum gonadotrophin), and gn-RH (gonadotrophin-releasing hormone) effective in terms of triggering ovulation were determined in a mouse ovulation test. Varying doses of the above preparations were subcutaneously injected, 48 hours after overstimulation by injection of 0.5 or 1.0 IU of PMSG. The animals were sacrificed for examination, after another 18-20 hours had passed. Roughly 50 per cent of all animals treated (threshold) in one and the same dosage group (n = 5) had ovulated in response to 0.02-0.1 IU of FSH per animal. The following FSH and PMSG dosages are recommended: 0.02, 0.04, 0.06, 0.08, and 0.1 IU of FSH, 0.6, 1.0, 1.4, 1.8, 2.2, 2.6, 3.0 IU of PMSG. When mouse ovulation tests were used in orientation studies, ovulation was regularly induced by Gn-RH doses per animal between 0.01 and 1.0 micrograms. Dosage spacings or increments should be specified with higher accuracy by further studies.     

应用不同剂量PMSG对CIDRS处理的不同年龄母羊春季同期发情效果初探

春季应用330和500单位两种剂量PMSG对经CIDRS处理过的小尾寒羊同期发情效果进行探研。结果表明,在年龄相同时,后者比前者同期发情率可提高35．8个百分点;相同剂量的PMSG而不同年龄的小尾寒羊应用效果也有所不同,在1～4岁之间,随羊年龄增加,同期发情率有明显的增高趋势,3～4岁的母羊比1～3岁母羊提高了21．5个百分点。     

Estrus and ovulation synchronization in Merino meat sheep. 1. Effect of Gonavet "Berlin Chemie" after estrus synchronization with prostaglandin F2 alpha in Merino meat sheep]

Oestrus synchronisation by means of PGF2 alpha analogues was followed by injection of Gonavet "Berlin-Chemie" which triggered off an LH peak, 2 to 3 hours from injection. Injection of Gonavet "Berlin-Chemie", 44 hours after PGF2 alpha application, caused synchronisation of all LH peaks. The interval between injection of Gonavet "Berlin-Chemie" and onset of ovulation amounted to 22 hours. The length of ovulation was not accurately determinable. Ovulation was successfully induced to all sheep by application of Gonavet "Berlin-Chemie", 44 or 48 hours after PGF2 alpha injection. Ovulation rates were 1.75 or 1.54. Luteolytic action on sheep of Cloprostenol "Jenapharm", a PGF2 alpha analogue, proved to be just as good as that of Oestrophan (SPOFA).     

Effects of Gn-RH on blood serum hormone concentrations, ovulation rates and embryo production in lactating cows treated with PMSG.

The effects of gonadotrophin releasing hormone injection into pregnant mare serum gonadotrophin treated cows on serum levels of luteinizing hormone, estradiol-17 beta and progesterone and ovulation rates was evaluated in 20 cows. Pregnant mare serum gonadotrophin treatment does not always induce superovulation as was shown in this study. Luteinizing hormone levels reached peak concentrations at 1.0 h and remained significantly (P less than or equal to 0.05) elevated at 2.0 h, 3.0 h, 4.0 h, and 7.0 h after the first gonadotrophin releasing hormone injection. Progesterone levels in the gonadotrophin releasing hormone treated group were significantly (P less than or equal to 0.05) higher than in the controls on the third and fourth days following injection. A significant correlation (r = 0.58-0.72) was noted between the number of corpus luteum and progesterone levels on each day between day 2 and day 7. More embryos were recovered (46 vs 26) from the ten treated than from the ten control cows.     

Administration of p.g. 600 to sows at weaning and the time of ovulation as determined by transrectal ultrasound

This study determined whether the interval from estrus to ovulation was altered by giving P.G. 600 to sows at weaning. Mixed-parity sows received P.G. 600 i.m. (n = 72) or no treatment (n = 65) at weaning (d 0). Beginning on d 0, sows were observed for estrus twice daily. At the onset of estrus and thereafter, ultrasound was performed twice daily to determine the average size of the largest follicles and time of ovulation. Weaning age (20.1+/-0.4 d) did not differ (P > 0.10) between treatments. More P.G. 600 sows expressed estrus within 8 d (P < 0.01) than controls (94.4% vs 78.4%, respectively). Parity was associated with expression of estrus (P < 0.02), with 78% of first-parity and 93% of later-parity sows exhibiting estrus. However, no treatment x parity effect was observed (P > 0.10). The interval from weaning to estrus was reduced (P < 0.0001) by P.G. 600 compared with controls (3.8+/-0.1 d vs 4.9+/-0.1 d). Follicle size at estrus was not affected by treatment (P > 0.10). The percentage of sows that ovulated did not differ (P > 0.10) for P.G. 600 and control sows (90.3% vs 81.5%, respectively). Time of ovulation after estrus was not affected by treatment and averaged 44.8 h. However, univariate analysis indicated that the interval from weaning to estrus influenced the interval from estrus to ovulation (r = 0.43, P < 0.0001). Further, multivariate analysis showed an effect of treatment on the intervals from weaning to estrus, weaning to ovulation (P < 0.0001), and estrus to ovulation (P < 0.04). Within 4 d after weaning, 81% of the P.G. 600 sows had expressed estrus compared with 33% of controls. However, this trend reversed for ovulation, with only 35% of P.G. 600 sows ovulating by 36 h after estrus compared with 40% of controls. The estrus-to-ovulation interval was also longer for control and P.G. 600 sows expressing estrus < or = 3 d of weaning (45 h and 58 h, respectively) than for sows expressing estrus after 5 d (39 h and 32 h, respectively). Farrowing rate and litter size were not influenced by treatment. However, the interval from last insemination to ovulation (P < 0.02) indicated that more sows farrowed (80%) when the last insemination occurred at < or = 23 to > or = 0 h before ovulation compared with insemination > or = 24 h before ovulation (55%). In summary, P.G. 600 enhanced the expression of estrus and ovulation in weaned sows but, breeding protocols may need to be optimized for time of ovulation based on the interval from weaning to estrus.     

Effect of biotechnical management procedures on blood parameters in gilts. 1. Acid and alkaline phosphatase

Three independent experiments were conducted with cyclic gilts kept under different conditions (2 x 12 on platforms and 100 from production unit), i.e. hormonally unaffected or under the usual conditions of synchronised oestrus (100 mg Suisynchron per animal and die over 20 days followed by 1,000 I.U. PMS and again followed, three days later, by 250 I.U. HCG). Blood samples were repeatedly drawn from the jugular vein and brachiocephalic vein during phases of treatment and oestrus. Acid and alkaline phosphatases were determined immediately in the plasms, and the results were calculated by variance analysis. Synchronisation, using Suisynchron, proved conducive to lowering with significance (P less than 0.01) the levels of acid and alkaline phosphatases. All changes in phosphatase values were not in full conformity within the experiments during the other phases of treatment. Phosphatase levels were not affected by discontinuation of Suisynchron nor by administration of Gn hormone. The levels of acid and alkaline phosphatases in biotechnically treated animals appeared to be lower than those in animals with spontaneous oestrus at the time of full oestrus. While the findings were of period-specific significance (P less than 0.01), the results obtained from the individual animal failed to provide specific information, since gaps were too wide between animals and between animals, on the one hand, and periods, on the other (P less than 0.01).