The effect of the seasons on the ovarian response in sheep after the administration of the serum gonadotropin, PMSG

In the autumn oestrus season, 20 Slovak Merino ewes were exposed to synchronization of oestrus, treated with the PGF2alfa at doses 125 micrograms (Oestrophan, inj. Spofa). followed by an injection of PMSG at doses 1000 IU (Antex Leo Denmark) and 50,000 IU of Vitamin A (Axerophtol Spofa). 23 anoestrus ewes were synchronized with an intravaginal sponges containing 20 mg of chlorsuperlutine (Agelin, Spofa) for 12 days and after sponge withdrawal, the ewes were injected with 750 and 1000 IU of PMSG (Antex Leo Denmark). Ovulatory response was observed and the possibility of ova recovered from the genital organs in ewes after synchronization of oestrus and superovulation in oestrus season. Higher values of the total follicular response (CFO), and the average number of ovulation (PO) after administering equal doses of PMSG were found out both in anoestrus ewes (CFO 6.62 +/- 4.24; PO 4.25 +/- 4.52) and in oestrus ewes (CFO 2.70 +/- 2.10; PO 2.60 +/- 1.74; resp. CFO 2.80 +/- 1.83; PO 3.4 +/- 3.0), if the ewes were treated with PMSG together with vitamin A. The average number of ova flushed was higher in anoestrus ewes (3.0-0.5) than in oestrus ewes (1.67-3.75). In both trials the equal ratio in the number of released ova was gained from ewes of experimental groups (83-88% of the total number). After ova flushing from the genital organs in ewes of the experimental groups most ovas were found in the isthmatal part of the uterine tube (36-60%). On the basis of gained results it was concluded, that synchronized oestrus ewes on receiving PMSG in anoestrus season the ovarial response was more significant than in autumn breeding season.     

Biometric parameters of the uterus and ovaries in sheep after administration of Depotocin inj. Spofa in early puerperium]

Objectivisation of the physiological course of puerpery and control of involution processes of uterus represent topical questions of an increased frequency of lambing. Our study was directed at the determination of the weight, length of body and horns of uterus as well as of the weight, length, width and height of ovaries, following the administration of carbetocin (Depotocin inj. Spofa), in the puerperal period of Slovak Merino sheep. The study was aimed at obtaining objective biometric data on uterus and ovaries and recording the influence of carbetocin on the involution of uterus and ovaries of sheep. Thirty ewes, divided into two groups, were included in the experiment. The animals of the experimental group (n = 15) were subjected to treatment with carbetocin (Depotocin inj. Spofa) at the amount 2 x 0.07 mg. The first dose was applied intramuscularly (i. m.) on the 2nd day after parturition and the second dose was injected subcutaneously (s.c.) on the 4th day after lambing. The second group (n = 15) served as a control. Three ewes (n = 3) were bled on each of the following days: 1, 7, 17, 25 and 34 after parturition. After bleeding the sexual organs were removed by excision and their weight and the length of the body and horns of uterus and of ovaries was determined. The number and size of follicles were determined on the surface of ovaries. The weight of uterus body showed a declining tendency in sheep of the control group with a statistically significant decrease from the 17th till the 34th day after parturition (P less than 0.01). Its weight varied from 56.0-14.6 to 5.2-0.3 g in the above-mentioned time interval. The experimental group showed a statistically significant decrease in weight as early as on the 7th day after lambing compared to the 1st day after parturition, down to the values 185.66-38.91 g (P less than 0.05). The decrease in the weight of uterus body recorded on day 17 (106.56-41.08 g) was less pronounced than in the control group. The final average weight of the body of uterus on the 34th day after parturition was 41.36-8.52 g, that means higher than in the control group (5.2-0.3 g). The weight of gravid horns in the experimental group declined significantly as early as on the 7th day after parturition to the average weight of 60.89-9.45 g and reached 9.86-3.49 g on the 34th day.(ABSTRACT TRUNCATED AT 400 WORDS)     

Dynamics of changes in the serum levels of cholesterol, thyroid and ovarian hormones in the postpartum period in ewes]

Postparturient anoestry, spontaneously changing over to seasonal anoestry, represents an important reserve of full utilization of the reproductive potential of sheep. In spite of the fact that the length of gestation in sheep only amounts to 148 days (+/- 5 days), inability of most sheep to enter the cycle during the spring season acts as a factor limiting the number of lambings--and at the same time production of lambs--to one lambing per year. In order to obtain more detailed knowledge of hormonal conditions in sheep puerpery, the presented work was directed at the study of dynamic changes in concentrations of thyroxine (T4), triiodothyronine (T3), 17 beta-estradiol (E2), progesterone (P4) and cholesterol (Chol) in the blood serum of ewes and at their mutual correlative dependences between the 36th hour and the 51st postparturient day. The observation was carried out in nine nursing ewes of the Slovak Merino breed, with average weight 40-50 kg, lambed in January and February. Blood was sampled by means of jugular vein puncture 14 days (-14th day) before parturition (a. p.), up to 36 h after parturition (p. p.) and on day 4, 7, 14, 17, 21, 25, 34, 42 and 51 p. p. In the period from the 36th h to day 21 p. p., concentrations of T4 (Tab. I, Fig. 1) showed a decreasing tendency compared to the starting -14th day (69.55 +/- +/- 0.12 nmol.-1) with the exception of a temporary increase on the 7th day p. p. The lowest values were recorded on days 4 and 21 p. p. (45.66 +/- 21.61 nmol.l-1, P less than 0.05 and 54.89 +/- 11.06 nmol.l-1, P less than 0.05, resp.). An increase of these values to the starting level was observed between days 25 and 51 p. p. Compared to the values on -14th day (0.76 +/- 0.22 nmol.l-1), a significant increase of T3 concentrations (Tab. I, Fig. 2) was recorded at the 36th h and on days 4 and 7 p. p. with the highest values (1.48 +/- +/- 0.34 nmol.l-1, P less than 0.001) at 36 h p. p. After the temporary decrease between days 14 and 21 p. p. its concentrations showed a constantly rising tendency statistically significant on days 34, 42 and 51 p. p., compared to the -14th day (P less than 0.05). Concentrations of E2 (Tab. I, Fig. 3) reached the values of 0.44 +/- 0.41 nmol.l-1 on the -14th day.(ABSTRACT TRUNCATED AT 400 WORDS)     

Quantitative micromorphological study of the ovaries in sheep after estrus synchronization and superovulation in the autumn mating season

The quantitative micromorphological changes of tertiary follicles and corpora lutea (CL) were studied in ewes in the autumn mating season after oestrus synchronization, induced by administration of PGF2 alpha (Oestrophan Spofa) at a rate of 125 micrograms, and after superovulation, induced by administration of PMSG (Antex Leo, Denmark) at a rate of 1000 I. U., or PMSG at rates of 750 and 1000 I. U. together with 50,000 I. U. vitamin A (Axerophthol Spofa). The highest number of ovulations was obtained in ewes treated with 1000 I. U. together with vitamin A (3.4 +/- 3.0) and after administration of 1000 I. U. PMSG alone (2.6 +/- 2.74). The highest number of tertiary follicles was recorded in ewes after administration of PGF2 alpha. The proportion of tertiary atretic follicles was the highest in ewes after administration of PMSG (64.6%). The occurrence of the luteinizing form of atresia was recorded only in ewes treated with PMSG (4% of the total number of atretic follicles). Using the caryometric analysis of the luteal cells of corpora lutea, the ewes of the experimental groups had two-peak variation curves; this corresponds to the theory of the presence of two luteal types in the tissue of the corpus luteum in ewes. As determined morphometrically, the smallest proportion of connective tissue out of the total volume of ewes' ovaries was found after administration of 1000 I. U. PMSG together with vitamin A. Administration of vitamin A together with PMSG had a favourable influence on the over-all follicular response, on the average number of ovulations, and on the proportion of non-atretic follicles.     

Dynamics of changes in the cytological picture of vaginal smears and circulating ovarian hormones during the puerperal period in ewes]

A postparturient period is characterized by low basal secretion of adenohypophysis gonadotropins with the following appropriate changes in ovarian hormones and their response to the morphology of vaginal epithelium. In this study the dynamics of the cytological picture of vaginal swabs and ovarian hormones 17 beta-oestradiol (E2) and progesterone was investigated in the puerpery of ewes. The objective was to obtain and extend the knowledge of cytological changes in vaginal epithelium and levels of ovarian hormones of ewes after parturition and of their relationships from the first several days after lambing until the 51st day of the period of observation. Vaginal swabs for vaginal cytology were taken from nine ewes on days 1, 4, 7, 14, 17, 21, 25, 34, 42 and 51 after parturition. These swabs were fixed in ether-alcohol 1:1, stained according to the Faltínová-Zidovsky method, embedded in Canada balsam and evaluated by differentiation of cells according to Luksh (1953). Blood samples for E2 and P4 determinations were taken from the jugular vein in the same intervals as vaginal swabs. The serum was centrifuged and stored at -18 degrees C until use. E2 and P4 concentrations were determined radioimmunologically, using kits RIA-test ESTRA and RIA-test PROG from URVJT Kosice. A statistically significant decline (P < 0.05) of percentual representation of basal and parabasal cells (Fig. 1, Tab. I) on day 7 after lambing was replaced by their multiplication from day 14 reaching the values of 66.07 +/- 3.95 on day 42. A statistically significant decrease in intermediary flat cells (Fig. 2, Tab. II) was observed on days 14 (P < 0.001), 34 and 42 (P < 0.01; P < 0.001), in comparison with the first day after lambing. An evaluation of intermediary convoluted cells revealed their highest percentage on days 1 and 17 after parturition (34.65 +/- 4.77-20.62 +/- 12.57) and their decline to values in the range of 6.77 +/- 1.46-7.66 +/- 2.25 on the remaining days of the period of observation. Percent occurrence of superficial flat cells (Fig. 3, Tab. I) ranged from 3.9 +/- 1.10 to 10.63 +/- 7.23 from day 1 to day 51 after lambing. The lowest percentual representation (1.32 +/- 0.79-4.10 +/- 1.89) was recorded for superficial convoluted cells. Multiplication of the evaluated cells was observed, reaching the highest but insignificant representation (P > 0.05) on day 25 of postparturient investigation: 4.10 +/- 1.89 (Fig. 3, Tab. I). 17 beta-oestradiol (E2) concentrations were compared to the -1st day before parturition, when its values varied at the level of 2.45 +/- 0.64 nmol/l serum.(ABSTRACT TRUNCATED AT 400 WORDS)     

Monoamine oxidase activity in some brain areas of sheep after hormonal stimulation

The influence of hormonal superovulatory preparations Folistiman (450 IU FSH, Spofa, Prague) and serum gonadotropin (1500 IU PMSG, Spofa, Prague) on monoamine oxidase (MAO), the degradative enzyme of catecholamines, was investigated in some areas of the brain regulating reproductive functions (area preoptica of the hypothalamus, pituitary gland, and pineal gland) in ewes with synchronized oestrus (20 mg chlorsuperlutin) during the oestrous period using a radiochemical method. After intramuscular administration of 1500 IU PMSG, marked increase of MAO activity was found in the area preoptica (p < 0.05) and in the pituitary gland (p < 0.01) in comparison with the control group. No change occurred in MAO activity after ovarian stimulation with FSH. Administration of the above superovulatory preparations failed to induce MAO activity in the pineal gland of sheep.     

Morphologic and biochemical changes in the hypothalamus in hormonally stimulated sheep

The effect of exogenous hormonal preparations (PMSG, SG, PMSG + PGF2 alpha and FSH) was studied as exerted on neurosecretion and on changes in the nuclear volume of nucleus paraventricularis, nucleus ventromedialis, nucleus infundibularis and nucleus tuberomamillaris, and on histological changes in the third cerebral ventricle. Changes in catecholamine concentrations were determined in the rostral, medial, and caudal hypothalamus of the ewes. The study was performed with 28 ewes of the Slovak Merino breed during the oestrus period. The oestrus was synchronized by the Agelín vaginal tampons (Spofa). The ewes of four experimental groups were stimulated by the administration of 1000 I.U. PMSG (Antex-Leo), 1000 I. U. Serum Gonadotropin (Bioveta Ivanovice na Hané), 1000 I. U. PMSG with 250 micrograms Oestrophan inj. (Léciva Praha), and 450 I. U. Folistiman (VEB Arzneimittelwerk Dresden, GDR). The brain samples were processed by common histological methods. A caryometric analysis was performed at 3000-fold magnification and by measurement of 200 cells of one sample. The data were subjected to mathematical processing after Fischer and Inke (1956). The amount of neurosecretory material was evaluated by light microscopy (Nakahara, 1963). The multiplication of neurosecretion in the hypothalamic nuclei testifies to the fact that the administration of hormonal preparations stimulates the function of hypothalamic structures, which corresponds with the results of the caryometric analysis. It also ensues from the results that the administration of serum gonadotropins (PMSG and SG) at the dose of 1000 I. U. results in a statistically significant decline (P less than 0.001) of the concentrations of norepinephrine in the rostral, medial and caudal hypothalami of the ewes, although the PMSG preparation has a more pronounced effect when compared with SG. The hormonal stimulation with PGF2 alpha and with FSH causes no significant changes in the concentration of norepinephrine in the hypothalamus of the ewes. As norepinephrine is considered as a neurosecretion inhibitor, the multiplication of neurosecretion in the hypothalamus nuclei after stimulation with serum gonadotropins correlates with the decline of hypothalamic norepinephrine concentrations.     

The effect of synchronization on estrus and pregnancy in sheep and on levels of thyroxine, triiodothyronine, 17 beta-estradiol, progesterone and cholesterol]

Knowledge of pathogenesis of sexual dysfunctions at altered thyroid activity is limited by the knowledge of multiple and ubiquitous action of its hormones throughout the organism. One of the possibilities of modulatory influence of thyroid hormones on sexual functions can be realized through the participation of thyroxine and triiodothyronine in the synthesis and metabolism of primary substrate of steroid synthesis--cholesterol. The presented work is aimed at the study of simultaneous dynamic changes of concentrations of thyroxine (T4), triiodothyronine (T3), 17 beta-estradiol (E2), progesterone (P4) and cholesterol (Chol) during synchronization of the rutting period and gravidity at parallel correlative evaluation of mutual relations of the followed parameters in ten Merino sheep in the seasonal period. Synchronization was achieved by chlorsuperlutin (Agelin--vaginal swabs, Spofa; 20 mg of chlorsuperlutin/swab) and PMSG (500 I. U./animal). Blood was sampled by means of a jugular vein puncture at the time of swab insertion (-13th day) and after three (-10th day) and seven (-7th day) following days, at the removal of swabs and application of PMSG (-3rd day), on the day of insemination (zero day), on the 7th, 14th and 17th day and in the middle of the 2nd, 3rd, 4th and 5th month of gravidity. In the phase of oestrus synchronization a significant increase of E2 concentrations on days -7 and -3 of the experiment (0.47 +/- 0.079 and 0.542 +/- 0.177 nmol.l-1 of serum, P less than 0.001; P less than 0.001) was observed compared to the E2 values on day -13 (0.084 +/- 0.036 nmol.l-1 of serum). Parallel to these observations, marked intermittent changes of T4 (Tab. I, Graph 1) were recorded with the lowest values of this parameter observed on days -10 (41.75 +/- 20.23, P less than 0.05) and -3 (50.22 +/- 18.77, P less than 0.05) and the highest on day -7 (96.77 +/- 17.51 nmol.l-1, P less than 0.01) and day zero (85.40 +/- 19.59 nmol.l-1 of serum, P less than 0.05) in comparison with the -13th day (67.22 +/- 18.29 nmol.l-1 of serum). Concentrations of P4 (Tab. I, Graph 4) declined to the lowest values on day zero observation (0.09 +/- 0.08 nmol.l-1 of serum, P less than 0.05 vs 3.40 +/- 3.61 nmol.l-1 on day -13). No significant changes of concentrations of T3 (Tab. I, Graph 2) and Chol (Tab. I, Graph 5) were observed during oestrus synchronization. During gravidity, concentrations of E2 (Tab. I Graph 3) showed an increasing trend compared to the -13th day.(ABSTRACT TRUNCATED AT 250 WORDS)     

Changes in the biometry of the sex organs of sheep after estrus synchronization and superovulation in the breeding period

In twenty ewes of the Slovak Merino breed coming from a demonstration farm at Zemplínska Teplica, to the age of two-three years biometrical variations of the sex organs and overall follicular response to PMSG and PGF2 alpha administration were investigated in the autumn period (October-November). In the ewes of all groups the heat was synchronized by i. m. administration of PGF2 alpha (Oestrophan Spofa) at a dose of 125 micrograms in the interval of 11 days. On the ninth day the ewes of the second and fourth group were given 1000 i. u. of PMSG (Antex Leo, Denmark), the ewes of the third group 750 i. u. of PMSG. The ewes of the third and fourth group were administered at the same time 50,000 i. u. vitamin A (Axerophtol Spofa) (each group). The weight and dimensions of the sex organs were investigated. The results demonstrate that the administration of PMSG in the mating period increases significantly the weight of oviducts and horns of uterus in the ewes while there are no variations of the weight of the other sex organs and of their length, or it is lower than in the ewes of the control group. The overall follicular response was not influenced by the higher weight of ovaries.     

Prevention of anestrus in sows after the 1st and 2d parturition

The procedure of prevention of anoestria after the weaning of piglets was verified in 389 experimental and 332 control sows of the Prestice breed. The set of animals under study included 77 experimental and 122 control primiparae, 68 experimental and 71 control secundiparae, and 244 experimental and 139 control multiparae (i.e. sows with three or more parturitions). The experimental sows were treated with 1000 IU of serum gonadotropin ad usum vet.-Bioveta-(PMSG) the first day after the weaning of piglets and with 300 IU of chorion gonadotropin (HCG) in the Praedyn inj. Spofa preparation together with 1 ml of Dirigestran inj. Spofa (40 micrograms LHRH) 72 hours later. Control sows were not treated with hormones. The treated primiparae and secundiparae respectively, had a significantly higher percentage of oestrus onset within 10 days after weaning and lower occurrence of anoestria over 10 days after weaning by 31.25 per cent (P less than 0.001), and 21.36 per cent (P less than 0.02) respectively as compared with untreated controls. In the set of secundiparae, the studied hormonal treatment speeded oestrus onset by a significant (P less than 0.01) shortening of the interval from weaning to the first insemination by 0.79 day and by a more frequent onset of oestrus within only 5 days after weaning of piglets. The values of the other criteria of reproduction studies, i.e. percentage of pregnancies after the first insemination, total number of born piglets and number of liveborn piglets converted per one litter in treated primiparae and secundiparae did not differ significantly (P greater than 0.05) from the control.(ABSTRACT TRUNCATED AT 250 WORDS)     

Untersuchungen zur Brunstsynchronisation und Samenübertragung bei Schafen verschiedener Rassen

Inhalt Bei insgesamt 500 Schafen (260 Merino, 120 Dagliç, 120 Ramliç) in drei Schafzuchtbetrieben in der Türkei wurde durch Verabreichung von Gestagen-Vaginal-schwämmchen + PMSG oder PGF_2α (ein- bzw. zweimal) die Brunst induziert. 4 bis 6 Stunden nach der Brunstbeobachtung mittels Suchbock erfolgte die zervikale Besamung mit tiefgefrorenem (TG) oder frisch gewonnenem Sperma von Böcken der jeweils selben Rassen. Mit Hilfe von Gestagen+PMSG wurde bei allen Rassen die höchste Östrusinduktionsrate (96, 7 bis 98,3%) erzielt. Einmalige PGF_2α Verabreichung rief bei 60%, zweimalige PGF_2α Injektion im Abstand von 9 Tagen bei 88,3% der Schafe Brunst hervor. PGF_2α hatte den besten Synchronisationseffekt (80,6 bis 88,2%) 48 Stunden nach der Applikation. Die Non Return Raten 35 bis 40 Tage nach Besamung betrugen unabhängig vom Synchronisationsverfahren und von der Rasse 21,4 bis 41,9% bzw. 55,6 bis 84,2% nach Verwendung von TG- bzw. Frischsamen. Die besten Non Return Ergebnisse wurden bei den drei Rassen nach Brunstinduktion mit Gestagen+PMSG beobachtet. Rasseabhängige Unterschiede bezüglich der Brunstinduktion-und -synchronisation ließen sich statistisch nicht absichern. Contents: Investigations upon oestrus synchronization and artificial insemination in ewes of different breeds In a total of 500 ewes (260 Merino, 120 Dagliç, 120 Ramliç) of three sheep breeding farms in Turkey oestrus induction was performed by application of progestagen imprepated vaginal sponges+PMSG or of PGF_2α (given once or twice). 4 to 6 hours after oestrus detection by a teaser ram the ewes were inseminated cervically with frozen-thawed or fresh semen of rams of the same breeds. In all breeds the highest rate of oestrus induction (96.7 to 98.3%) was obtained by means of progestagen+PMSG. A single injection of PGF_2α provoced heat in 60%, while two injections with an interval of 9 days induced oestrus in 88.3% of the treated ewes. PGF_2α had the best synchronizing effect (80.6 to 88.2%) at 48 hours after application. Regardless of the breed and the synchronization method, the non return rates 35 to 40 days after insemination were 21.4 to 41.9% and 55.6 to 84.2% for frozen-thawed and fresh semen resp. In all breeds the best non return results were observed after oestrus induction with progestagen+PMSG. With regard to induction and synchronization of oestrus breed dependent differences could not be statistically confirmed.     

Pregnancy in dairy cows in various times of the year in relation to thyroxine and triiodothyronine levels

Conception of dairy cows was investigated in relation to changes in thyroxine (T4) and triiodothyronine (T3) concentrations in March (n = 15), June (n = 10) November (n = 7) after oestrus synchronization by cloprostenol (Oestrophan Spofa) at a dose of 0.05 mg per head. The cows were inseminated from 8.00 to 9.00 o'clock a.m. Blood was taken from 9.00 to 10.00 a.m. from v. jugularis on the day of Oestrophan treatment (-3rd day), on the day of insemination (day 0), and on the 6th and 21st day after insemination. The lowest percentage of pregnant cows (26.67%) was recorded after the March insemination, the highest (50.0%) after the June insemination. 42.86% of cows became pregnant in November. Concentrations T4 in pregnant animals on the day 0 of March insemination were 67.55 +/- 16.95 nmol.1-alpha of serum. Nonsignificant decrease to value 65.60 +/- 10.06 and 49.33 +/- 17.47 nmol.l-1 of serum were observed on the day of June and November insemination. In T3 concentrations an average decrease from the values of 2.53 +/- 0.67 nmol.l-alpha on day 0 of the March insemination to 1.48 +/- 0.67 nmol.l-alpha on day 0 of the June insemination was observed, as well as a significant decrease to 0.80 +/- 0.45 nmol.l-1 of serum (P less than 0.05) on the day of the November insemination. Considering the results we suppose that the conception of dairy cows has an indirect relationship to thyroid hormones.     

Effect of Exogenous GnRH at the Time of Artificial Insemination on Reproductive Performance of Awassi Ewes Synchronized with Progestagen–PMSG–PGF2α Combination

This study was carried out to investigate the efficacy of PGF_2α for oestrus synchronization (ES) in Awassi ewes to which were administered the progestagen–PMSG combination, and to evaluate the effect of the exogenous GnRH administration immediately after the artificial insemination (AI) on their pregnancy rate and lambing performance during the breeding season. The ewes (n = 33) were treated with an intravaginal sponge impregnated with 30 mg fluorogestane acetate for 12 days and were injected with 500 IU PMSG at the time of removal of the sponge. The ewes were then divided into three equal groups of 11 ewes each. One millilitre of physiological saline (0.9% NaCl; placebo) was administered to each ewe in Group 1 at the time of second AI. Approximately 4 μg GnRH (busereline) was injected to each ewe in Group 2 immediately after second AI. A total of 150 μg PGF_2α (cloprostenole) was injected at the time of sponge removal on day 12 and 4 μg GnRH immediately after the second AI was also treated to each ewe in Group 3. Intracervical AI with diluted fresh semen was performed twice at 12 and 24 h following the onset of oestrus. The injection‐oestrus onset and injection‐oestrus‐end interval in Group 3 was significantly (p < 0.001) shorter than both Groups 1 and 2. Although the pregnancy rates of Groups 2 and 3 (81.8%; 9/11) were numerically higher than of Group 1 (63.6%; 7/11), the difference among the groups was statistically insignificant. The multiple birth rate of Group 3 was found higher than Groups 1 and 2. However, the number of single lambs of Group 1 was also higher than Groups 2 and 3 (p < 0.05). Despite the litter sizes of Groups 2 (1.27; 14/11) and 3 (1.55; 17/11) being numerically higher than Group 1 (0.73; 8/11), the differences among all the groups were statistically insignificant. In conclusion, the administration of PGF_2α at the time of removal of the sponge shortens the injection oestrus‐onset and oestrus‐end interval in Awassi ewes treated with progestagen–PMSG. Additionally, exogenous GnRH treatment immediately after the AI increases the multiple birth rate of Awassi ewes synchronized with progestagen–PMSG–PGF_2α combination.     

The effect of beta-carotene on thyroxine and cholesterol levels in pregnant heifers before and after parturition

Thyroxine (T4) and cholesterol concentrations and their dynamic changes and differences were studied in 20 pregnant heifers 10 days before calving until 56 days after calving. Ten control heifers were fed the feed ration for pregnant heifers according to Czechoslovak Standard CSN 46 7070. The feed ration given to another ten (experimental) heifers was fortified with 300 mg of synthetic beta-carotene per head/day within the period of five months before insemination, during pregnancy and till the 56th day after parturition. As suggested by the regression function of straight line, no obvious differences were recorded in the dynamic changes of T4 before parturition and during the first days after parturition. T4 concentrations had a generally descending tendency in both groups, the lowest values being recorded in the 48th hour in the experimental group and the 24th hour in the control. A marked increase of T4 concentrations with the values significantly higher in the control group than in the experimental group was observed between the 21st and 35th day after calving. A medium increase of cholesterol concentrations was found in the heifers given rations fortified with beta-carotene. No significant differences in cholesterol concentrations were observed between the two groups, except in the 72nd hour and the seventh day. Significant T4: cholesterol correlations were recorded in the experimental animals in the first and second hours, on the 42nd day (P less than 0.05), and in the 72nd hour (P less than 0.001); in the control group these observations were made the seventh day before calving and in the sixth hour and on the 14th, 21st and 56th days (P less than 0.05) after calving. It is inferred from the results that beta-carotene interferes with the activity of the thyroid gland and the production of its hormones, and that the increases or decreases of the activity of this gland, caused by beta-carotene, influence the metabolism of cholesterol in the body.     

The Effect of Gonadotrophin Releasing Hormone and Follicle Stimulating Hormone in Conjunction with Pregnant Mare Serum Gonadotrophin on the Superovulatory Response in Crossbred Sheep In India

Thirty-two mature crossbred (Fine Wool Synthetic, FWS) sheep developed for fine wool production in India were treated for superovulation and oestrus synchronization in spring season. The ewes were randomly allocated to four treatment groups in a factorially designed experiment. For induction of superovulation, pregnant mare serum gonadotrophin (PMSG) was administered alone (group 1), in combination with gonadotrophin releasing hormone (GnRH) (group 2) or with follicle stimulating hormone (FSH) (group 3) and with both (group 4). Oestrus was synchronized in all the ewes by two injections of prostaglandin F2 (PGF, 10 mg each) administered at an interval of 10 days. Superovulation treatment started 48 h prior to the second PGF injection. The proportion of ewes in oestrus did not differ significantly (p>0.05) in the four groups. The use of GnRH set the ewes into oestrus earlier than the ewes in the other groups. Treatment with PMSG (800 IU) in conjunction with 4 g of Buserilin (GnRH) increased the ovulation rate (9.1±2.6 corpora lutea (CL)) above that observed when PMSG was used alone (3.0±0.7 CL). The use of FSH (0.5 U ovagen) in conjunction with PMSG was characterized by a decrease in the proportion of ewes with 2 CL (4/8 vs 7/8; p<0.05) and in the number of ovulations, i.e. CL observed (2.4±0.6 vs 9.1±2.6), and a nonsignificant increase in the incidence of large follicles (LF) (4.6±1.28 vs 3.25±0.6; p>0.05). The interaction between treatments of FSH and GnRH was not significant (p>0.05).It is concluded that use of GnRH, in conjunction with either PMSG alone or PMSG plus FSH treatment, advanced the onset of oestrus and increased the ovulation rate in FWS sheep.     

PMSG对甘肃高山细毛羊同期发情和繁殖率的影响

在甘肃省肃南县康乐乡对甘肃高山细毛羊应用阴道栓与孕马血清促性腺激素(PMSG) 结合处理,结果表明,不同注射剂量和处理方式对母羊的同期发情和繁殖率均有影响,在埋栓后12.5 d注射550 IU PMSG并在放栓后14 d撤除阴道栓后的0-48 h发情率显著高于其他试验组(P<0.05);在埋栓后13 d注射600 IU PMSG同时撤除阴道栓的试验组繁殖率最高(P<0.05)。但综合繁殖率和经济效益考虑,在埋栓后间隔12.5 d注射550 IU PMSG并在放栓后14 d撤除阴道栓0-48 h的试验组效果最好,平均每只母羊净收入可达773.7元。     

Prolonged interval between parturition of normal live pups in a bitch

On day 64 after artificial insemination, a six-year-old primiparous briard bitch whelped three live pups between 05.00 and 08.00. It was presented at 11.00 on the same day with failure to complete parturition. On ultrasound examination, a normal live fetus was observed and the bitch was treated with oxytocin three times during the day (1.0, 2.0 and 2.0 iu intramuscularly), with no effect. The following day, a higher dose of oxytocin (5.0 iu) was administered intramuscularly at 11.00, after a uterine ultrasound examination confirmed viability of the fetus. At 18.00 of the same day, the bitch whelped the fourth normal live pup, 37 hours after initiation of parturition and 34 hours after expulsion of the last fetus. Effectiveness of oxytocin and normal versus prolonged parturition due to uterine inertia are discussed.     

The effect of vitamin A on trypsin inhibition activity of the blood and cervical mucus after the effects of hormones on the ovaries of sheep in the estrus period

Vitamin A (50,000 I. U.), administered after oestrus synchronization by PGF2 alpha (2 X 125 micrograms; 1st and 11th day) together with PMSG (750 and 1000 I. U.), had a stronger influence on the changes in the trypsin-inhibition activities (TIA) of the blood plasma, as compared with the effect of PMSG. The changes in the average TIA values within 120 hours after the administration of the stimulating dose were also observed more frequently to depend on vitamin A. After administration of 1000 I. U. PMSG, an increase was recorded only in the values of the fraction of low-molecular TIA, whereas the administration of the combinations of PMSG + vitamin A resulted in an increase of all the TIA's under study. This increase was directly correlated with an increased number of non-atretic tertiary follicles, with an increased number of ovulations (at the same dose of PMSG), and with a reduced ratio of changes in the concentration of progesterone (P) and 17-beta oestradiol (E): P/E = 1.1 after the administration of 1000 I. U. PMSG, P/E = 0.81 after I. U. PMSG + vitamin A, and P/E = 0.90 after 1000 I. U. PMSG + vitamin A. The increase in the average TIA of the cervical mucus is due to the increased secretory activity of the cervical glands rather than to the multiplication of these glands after ovary stimulation.     

Aspects on Hormonal Control of Normal and Induced Parturition in the Dog

Average length of gestation on the dog is 63 ± 2 days but may vary between 57-71 days due to the long period of receptivity at oestrus and the extended period of sperm survival in the female genital tract. In contrast to other domestic animals progesterone- and oestrogen concentrations are almost identical in pregnant and non pregnant bitches, except for their rapid decline immediately prior to parturition. Control of luteolysis still poorly understood. Experiments with indomethacin leading to a blockade of the prepartal PgF_2α increase, which commences with the decrease of progesterone, point toward a role of PgF_2α at this stage of pregnancy, which was extended for several days. At physiological conditions first visible signs of parturition were observed at peak-PgF_2α levels, 33.6 ± 17.6 hours after onset of luteolysis, which lasted over 16.8 ± 3.4 hours. Pulse-type releases of oxytocin were only observed after this point of time. To test for the effect of progesterone-withdrawal, four 51-57 days pregnant bitches were treated with the antiprogestin RU 38486 which inhibits the activity of progesterone at the receptor level. In all dogs first visible signs of parturition were observed 33.5 ± 7.5 hours after onset of treatment. However, the process of parturition came to an end after cervical opening and totally only one puppy was born. Different to a normal parturition no increase of PgF_2α was observed. Relaxin levels were not influenced by treatment. These observations suggested that treatment with antiprogestin followed by PgF_2α might be an adequate method to induce parturition in the dog; first experiences seem to confirm this conclusion.     

围产期小尾寒羊血清T-SOD活性和MDA含量变化的研究

[目的]研究围产期小尾寒羊血清T-SOD活性和MDA含量的变化。[方法]选择20只年龄在2~5岁之间的小尾寒羊,其中10只为待产母羊,10只为空怀母羊,分别于产前20d、产前10d、产前1d、产后1d、产后10d、产后20d颈静脉采血,测定血清T-SOD活性和MDA含量。[结果]围产期小尾寒羊在整个围产期内血清中T-SOD活性呈先下降后逐渐升高的动态变化,其中,在产前1d出现最低值且围产期小尾寒羊T-SOD活性均低于空怀小尾寒羊;围产期小尾寒羊在整个围产期内血清中MDA含量呈先上升后逐渐下降的动态变化,其中,在产后1d出现最低值且围产期小尾寒羊MDA含量均高于空怀小尾寒羊。[结论]怀孕和分娩对小尾寒羊T-SOD活性和MDA含量有一定的影响。