Changes in the hypothalamus and adjacent ependyma after hormonal stimulation of the ovaries in ewes]

Superovulation treatment leaves alternations in the controlling regions of the hypothalamus and in the adjacent ependyme after ovulation. The test ewes were synchronized with Agelin (20 mg chlorsuperlutin in one vaginal sponge) and stimulated (after the removal of the sponges) with 750 IU PMSG + 750 IU HCG and with 1000 IU HCG and 750 IU PMSG + 5 ml Antisergon (goat antiserum against PMSG), administered 68 hours after PMSG (i.e. 40 hours after HCG). The control ewes were in different stages of the ovarial cycle. The experimental ewes were killed 120 to 130 hours after the start of stimulation. Routine histological techniques were used to treat the brain samples; this treatment was followed by assessment under light microscope. The ependyme epithelium of the third cerebral chamber was studied under scanning microscope. Preparations with different FSH:LH ratios had different effects on the nucleus ventromedialis. Antisergon administration influenced the secretion of NPV (prevented persistent stimulation), which was observed after administration of PMSG + HCG. On the surface of the lower part of the third cerebral chamber the administration of Antisergon slowed the formation of the miniblebs. Supraependyme cells disappeared after stimulation for superovulation.     

The effect of hormonal preparations on superovulation and egg transport in ewes

The relation between the prevalence of contagious mastitis with the finding of Streptococcus agalactiae and Staphylococcus aureus and the number of somatic cells in the tank samples of milk was studied on the basis of a clinical and bacteriological examination of 11 129 dairy cows on four large farms, with a capacity of 600 to 1240 animals. A statistically significant correlation was demonstrated between the analyzed characteristics (r = 0.621). The relation was demonstrated at a prevalence up to 25.3%. The number of somatic cells provides a marked indication of prevalence only from 10%. We failed to demonstrate a statistically significant correlation between the prevalence of mastitis with a cultivation finding significant correlation between the prevalence of mastitis with a cultivation finding of Staphylococcus aureus and the number of somatic cells in tank samples of milk (r = 0.054). The results suggest that on large farms it will not be possible to use only the number of somatic cells in tank milk samples as a signal of diagnostic improvement and preventive mastitis-control measures, since a 10% prevalence of these diseases usually excludes the possibility of herd sanitation.     

The secretion of luteinizing hormone in ewes of Finnish landrace during estrus

The secretion of luteinizing hormone in ewes of Finnish Landrace during estrus. Acta vet. scand. 1979, 20, 216–223. — Luteinizing hormone immunoreactivity was measured in the venous plasma of four cycling Finnish Landrace sheep during the breeding season in connection with one synchronized estrus and the subsequent one. The ewes were slaughtered after the second estrus to establish the number of ovulations. To determine the LH concentration, a heterologous method of assay was used; this was based on the cross reaction of sheep plasma LH in a human LH radioimmunoassay system.As a result of the investigation, it was found that the peaks of LH were lower during the time of synchronized estrus and that these peaks occurred earlier than in the subsequent estrus. However, the differences were not statistically significant. On account of the limited material, the effect of the occurrence of the LH peak on the number of ovulations could not be established.     

泌乳早期发情和乏情奶牛机体代谢和生殖机能的变化

在某一集约化牛场,随机选取奶牛30头,在奶牛产后发情期(50～90 d)内根据奶牛是否发情将奶牛分为发情组和乏情组。通过对试验奶牛血液生化指标(Glu、BHBA、NEFA)、内分泌指标(FSH、LH、LP、E2、P4)等进行调查和检测。结果显示:当奶牛发情时,机体血浆Glu、FSH、LH、E2和LP浓度高,血浆NEFA、P4浓度低,但乏情时正好相反。当奶牛发情时,血浆leptin与LH、E2呈显著正相关,与P4呈显著负相关,但乏情奶牛未呈现相关性。这些结果提示奶牛乏情与机体能量代谢状况和Ins、Gn、E2、P4、Lp分泌少有关。能量平衡能促进奶牛产后发情,与机体高水平血糖、Lp、FSH、LH、E2和低水平P4、NEFA有关。LP是奶牛泌乳早期发情的一个重要调控因子,在奶牛产后能量平衡、生产性能和繁殖性能之间起到一个平衡纽带的作用。     

Study of male effect on feeding and estrus behavior of Afshari ewes

Tropical Animal Health and Production - This study was conducted to evaluate the male effect on the manifestation of estrus and feeding behavior of Afshari ewes during their breeding season. The...     

Changes in the follicle system and the population of tertiary follicles in sheep after the administration of PMSG in anestrus

The total quantitative changes of ovaries, proportion of atretic and non atretic follicles and changes of tertiary follicles in sheep after administration of increasing doses of PMSG during the anoestrous period were observed. In experimental groups the statistically significant increase of average weight, volume and dimensions of ovaries in comparison with control group were determined biometrically. The average number of tertiary follicles was greater in experimental groups but at the same time we observed a higher proportion of atretic follicles (64% of the total number in the control group; 71-77% in the experimental groups). In the group of sheep administered a dose of 1500 m.u. PMSG we determined a high proportion of luteinized follicles (as much as 21% of the total number of atretic follicles). The total number of small follicles in the so called transient phase in the comparison of experimental and control groups was not changed significantly. In the experimental group an increased incidence of preovulatory follicles and a reduction of tertiary follicle dimensions in the period of follicle cavity formation was determined.     

Duration of anestrus in Pramenka and Romanov ewes in Yugoslavia.

Jugular plasma progesterone was determined for two groups of native Yugoslavian ewes (Pramenka, Groups 1 and 2) and for a group of Romanov ewes (Group 3) from the end of January to late October in 1988. Ewes were pregnant until the end of March (pregnancy progesterone concentrations, 2.84 to 33 ng/mL). From the end of March to the beginning of July, progesterone concentration decreased (0 to .15 ng/mL). From early July to late October, progesterone concentrations increased. Progesterone concentrations were at their nadir near the summer solstice and increased significantly by early July in all three groups. The duration of anestrus was similar in Pramenka and Romanov ewes. In nonpregnant Pramenka ewes, the pattern of changes in plasma progesterone was similar to those seen in pregnant ewes except for an earlier decline with very low concentrations observed after mid-March.     

Concentrations of testosterone in canine serum during late anestrus, proestrus, estrus, and early diestrus

Serum testosterone concentrations in samples collected daily from 6 bitches for at least 60 days before the onset of diestrus were determined by radioimmunoassay. Mean serum concentrations (+/- SEM) of testosterone ranged from 31 +/- 11 to 141 +/- 63 pg/ml during late anestrus. Mean testosterone concentrations during proestrus ranged from 106 +/- 29 to 239 +/- 113 pg/ml, with the highest concentration (526 +/- 225 pg/ml) occurring the day of the preovulatory surge of luteinizing hormone. Although the ovaries may be sites of production during late anestrus, proestrus, estrus, and early diestrus, further investigation is necessary to determine whether testosterone has an important physiologic or endocrinologic function in the bitch (ie, sexual behavior, vaginal hypertrophy, and luteinizing hormone surge).     

Morphologic picture of the ependyma of the 3d cerebral ventricle in ewes after hormonal stimulation

The ependyma in the infundibular region of the third cerebral ventricle was studied. Ageline sponges (20 mg per animal) were applied to nine ewes. On the thirteenth day after the removal of sponges, 750 I. U. PMSG was administered intramuscularly to three ewes, 1000 I. U. PMSG to another three, and the remaining three ewes were left without this treatment. Six ewes were the control. After embedding in paraffin, the material obtained from four control sheep and all the test sheep was stained with haematoxylin-eosine, material from another two control animals was impregnated by the method after Golgi-Cox. The ependyma in the infundibular region of anoestric ewes has a single layer and is cubic to cylindrical; it is only in the recessus infundibuli that it forms two to four layers. After the administration of Ageline, or in combination with PMSG, ependyma can be observed to react within the whole infundibular region of the third cerebral ventricle, but the most expressive reaction is recorded in the caudal part of the middle third of infundibulum where a transient type of cells (between ependymal cells and tanycytes) was found in the control animals after impregnation (they have cilia and one to two short and one long processes). After Ageline administration, ependymal cells in the middle third stretch out like in the anoestric period. The administration of 20 mg Ageline and 750 I. U. PMSG gave rise to low digital excrescences, the ependyma is undulated (pseudo-stratified) or contains small deposits of multiplied cells. After the administration of 20 mg Ageline and 1000 I. U. PMSG, the middle third contained, besides subependymal serous infiltrate, also large digital excrescences, probably filled with a serous fluid, and the surface of the subependyma and ependyma is eroded, containing proliferated deposits of ependymal cells of different thickness. Everywhere proliferation occurs, the surface layer of ependymocytes is desquamated into the cerebrospinal fluid. The histological picture described in the present paper probably suggests an increased secretory activity of ependymal cells after the administration of hormonal preparations. It is confirmed by these results that ependyma is involved in the hypothalamo-hypophyseal control of the sexual activity of sheep.     

Antiproteolytic activity of blood and cervical mucus in sheep after hormonal ovarian stimulation and gamma ray irradiation (2.45 Gy) during anestrus]

The antiproteolytic activities of the blood plasma (BP) and cervical mucus (CM) determined as trypsin inhibiting activities (TIA) where trypsin served as a model serine protease, were variable after superovulatory stimulations of ewes and after their gamma irradiation (2.45 Gy). TIA's were determined from the reduction in the bovine trypsin hydrolysis of the low-molecular chromogenic substrate N-alpha-tosyl-L-arginyl-p-nitro anilide (TAPA) (Bartík et al., 1974). The inhibition was expressed in per cent when delta A405 = 1.0 for 10-minute incubation at 25 degrees C, pH = 8.05, 0.2 mol/l tris-HCl buffer, was taken as 100%. Student's t-test was used for the statistical evaluation. A hundred ewes of the Merino breed were applied Agelin vaginal tampons (20 mg chlor-superlutin per head) on day 1 for 10 days in the anoestric period (May). A part of these ewes were subjected to whole-body gamma irradiation on days 6 to 11. When the irradiation was completed and the tampons were taken out, the ewes (three to four years old lambing ewes, yearling ewes) were stimulated to superovulations by an administration of 1500 IU serum gonadotropin (SG) or 450 IU follicle stimulating hormone (FSH). These parameters were followed in the subsequent 5-6 days: BP TIA (Figs. 1 and 4), fraction of low-molecular BP (n) TIA (Figs. 2 and 5), CM TIA (Figs. 3 and 6). Fig. 7 shows the average values of the results. The lambing ewes and yearling ewes had various responses to irradiation and superovulatory stimulation. Gamma irradiation eliminated the increase in BP TIA (P < 0.001) in the ewes after stimulations (Fig. 1a, b). The yearling ewes showed nonsignificant changes (ns) as their responses to SG stimulations and gamma irradiation, but the responses on the particular days of the trial were different (Fig. 1c, d--FSH stimulation). Similar changes were observed in the BP nTIA fraction. The changes in the average values of CM TIA were nonsignificant in the lambing ewes, the gamma irradiation reduced CM TIA only after FSH stimulation (P < 0.002). The amount of cervical mucus decreased after stimulations and irradiation, the thickness of ovarian epithelium and muscles was reduced in the particular parts, differently in lambing ewes and in yearling ewes.(ABSTRACT TRUNCATED AT 400 WORDS)     

Morphologic changes in the ovary and histologic changes in the tertiary ovarian follicles in ewes after prolonged irradiation during anestrus

The changes in volume, weight and the histomorphological changes of the tertiary follicles of ewes were studied after protracted irradiation with 4.8 Gy in the anoestrous period by the morphometric and qualitative histological methods. The trial was performed in May with 21 ewes of the Slovak Merino breed, divided into three groups. The first group (five ewes) was control. The second and third groups (each containing eight ewes) were exposed to gamma-rays for five days, the total dose being 4.8 Gy. Within ten days after the treatment, all the irradiated and control ewes were given Ampicillin Spofa per os at a dose of 250 mg per head/day and Roboran Spofa at a dose of 10 g per head/day. The animals were killed by bleeding on the fifth day of irradiation and on the tenth day after the end of the treatment. After killing, the volume and weight of the ovaries were determined and a common histological method was used to cut these ovaries into 7 microns slices in series 70 microns apart. The slices were stained with haematoxylin-eosine and were evaluated by means of light microscopy. After irradiation the weight of the ovaries was found to decrease significantly; however, ovary volume remained unchanged. The atretic and non-atretic tertiary follicles were subjected to qualitative histological differentiation after Marion et al. (1968) and the number of non-atretic follicles was found to have decreased significantly in the irradiated ewes. The late type of atresia contributes most significantly to an increase in the proportion of atretic tertiary follicles. The administration of vitamins after irradiation reduced the occurrence of atretic changes.     

The effect of PMSG on the trypsin inhibitory activity of the blood and cervical mucus and on the reproductive organs in sheep during anestrus

The effect of the doses of 750, 1000, and 1500 I. U. PMSG (Antex Leo) on changes in the trypsin-inhibition activities (TIA) of the blood plasma and cervical mucus of ewes was found to vary: a) in the times (from PMSG administration) of recording the minimum values of total TIA (72, 48, 24 hours); b) in the values of the average total TIA on individual days of the trial (40.3-141.4% of the control values); c) in the fractions of low-molecular TIA after administration of 750 and 1500 I. U. PMSG, the fractions exhibited minimum values after 24 hours, and of 1000 I. U. after 72 hours (53.0 and 60.4, and 69.7% of the control values, respectively); d) in the highest values of the fractions of low-molecular TIA recorded after 96 hours (96.1-183.7% of the control values); e) in the average values for 96 hours of the trial, which ranged from 64.1% (1500 I. U.) to 77.1% (750 I. U.) for total TIA and from 89.6% (750 and 1000 I. U.) to 122.8% (1500 I. U.) for low-molecular TIA; f) in the ratio of atretic and non-atretic (A/N) tertiary follicles, which grew with increasing PMSG doses; this was indirectly correlated with the average values for total TIA; g) in the weights of uteri and ovaria which increased from 176.8 to 322.3% of the control values after the stimulation; h) in the epithelium thickness of cervix and cervical glands increasing from 118% to 316% of the control values; i) in the average TIA values of cervical mucus ranging from 53.3 to 125% of the control values.     

Thyroid stimulating hormone and prolactin secretion after thyrotropin releasing hormone administration to mares: Dose response during anestrus in winter and during estrus in summer

The response of thyroid stimulating hormone (TSH) and prolactin (PRL) concentrations to administration of thyrotropin releasing hormone (TRH) was determined in light-horse mares during the anestrous season (winter) and during estrus (standing heat) in the summer. Within each season, mares (4/group) were treated with either saline (controls) or one of four doses of TRH (80, 400, 2,000 or 10,000 ug) intravenously. Samples of blood were drawn at −15, −.5, 15, 30, 45, 60, 90, 120, 180 and 240 min relative to TRH injection. Concentrations of TSH and PRL in pre-TRH samples were greater (P<.05) in anestrous mares during winter than in estrous mares during summer. Concentrations of TSH increased (P<.05) within 30 min after administration of TRH and remained elevated during the 4-hr sampling period. The maximal net change in TSH concentrations and the area under the response curve were greatest for 2,000 ug of TRH; 80 ug did not produce a significant TSH response. There was no interaction (P >.10) between reproductive state and TRH dose for TSH concentrations. Concentrations of PRL were not significantly affected by any TRH dose during either season. It appears that mares differ from many mammalian species in that they do not respond to an injection of TRH with increases in both TSH and PRL.     

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.     

A comparative study of induction of estrus and ovulation by three different intravaginal devices in ewes during the non-breeding season

The aim of the present study was to compare three methods of estrus synchronization in ewes during the non-breeding season. Forty-two ewes were randomly grouped for three treatments with different intravaginal devices for 12 days: Group A) CIDR, Group B) Self-made P sponge, Group C) MAP (medroxyprogesterone acetate) cream sponge. Furthermore, all groups were divided into two treatments with (R) or without ram presence to examine the "ram effect". Blood was collected from all treated ewes, and progesterone (P(4)), estradiol 17-beta (E(2)) and luteinizing hormone (LH) concentrations were measured by enzyme-immunoassay. All ewes showed estrus behavior between Day 0 to 3 after device removal, and the mean onset times of their estrus were 23.0, 33.0 and 21.0 h for Groups AR, BR and CR, respectively. On Day 5 as examined by laparoscopy, the ovulation rates (and number of ovulated ewes) were 1.45 (11/11), 1.25 (12/14) and 1.21 (14/14) for Groups A, B and C, respectively. In Group C, the time to LH surge was significantly (P<0.05) later (32.4 h) than those in Groups A (27.0 h) and B (25.5 h). Ram presence did not affect the number of ovulated ewes, ovulation rate or time to LH surge. The ram introduction group had significantly (P<0.05) lower E(2) concentrations during the period from 0 h to 36 h than the groups without ram presence. These results suggest that the self-made P sponge or MAP cream sponge was effective as well as CIDR, and ram introduction was not necessary, for induction of estrus and ovulation during the non-breeding season.     

Ovarian cyclicity in thyroid-suppressed ewes treated with propylthiouracil immediately before onset of seasonal anestrus

Two experiments were conducted to determine if propylthiouracil (PTU)-induced thyroid suppression immediately before onset of anestrus would extend the breeding season in mature ewes. In Exp. 1, twice-weekly serum concentrations of progesterone indicated that all ewes were cyclic before initiation of treatment. Beginning on d 0 (January 17), ewes received 0 (n = 4), 20 (n = 5), or 40 (n = 5) mg of PTU x kg(-1) of body weight (BW) x (-1) for 35 d. Blood samples were collected regularly throughout the trial and serum thyroxine and progesterone were quantified. Ewe BW were similar (P > 0.90) among treatments before the experiment began (mean = 78.2 +/- 4.5 kg). Likewise, serum concentrations of thyroxine averaged 86.5 +/- 8.0 ng/mL on d 0. After 11 d of PTU treatment, serum thyroxine was 90.2,75.2, and 44.2 +/- 14.0 ng/mL in ewes receiving 0, 20, and 40 mg of PTU/kg BW, respectively (linear effect, P = 0.04). On d 20, thyroxine values in the three respective groups were 73.0, 51.1, and 16.1 +/- 12.9 ng/mL (linear effect, P < 0.01). Fourteen days after PTU treatment ended, serum thyroxine did not differ (P = 0.53) among the three respective groups (71.4,73.3, and 57.5 +/- 11.8 ng/mL). Ewes receiving PTU tended to weigh less on d 42 (84.2, 78.2, and 71.8 +/- 5.1 kg for ewes treated with 0, 20, and 40 mg PTU/kg, respectively; linear effect, P = 0.10). Day of onset of anestrus was designated as the day on which serum progesterone decreased and remained below 1 ng/mL. Ewes treated with 0, 20, or 40 mg of PTU/kg BW became anestrous on d 16,40, and 81 (+/- 12) of the experiment, respectively (linear effect, P < 0.01). At the time the 35-d treatment period ended, 25, 60, and 100% of ewes receiving 0, 20, or 40 mg of PTU/kg exhibited normal estrous cycles. In Exp. 2, ewes received 0, 20, or 40 mg of PTU/kg BW for 14 d. The dose was then decreased to 0, 10, and 20 mg of PTU/kg BW for the remaining 21 d. Serum thyroxine decreased to concentrations below 20 ng/mL by d 9 after initiation of PTU treatment. Ewe weights did not differ throughout the trial and no BW loss was observed. The average day that each group entered anestrus was similar to those in Exp 1. Large doses of PTU dramatically lower serum thyroxine and this effect appears to inhibit onset of anestrus in ewes.     

The follicular system of bovine ovaries after estrus synchronization using the luteolytic action of cloprostenol

Oestrus synchronization was studied in samples from six cows of the Black-Pied Lowland breed. Three cows four to five days from oestrus were used as the control; three animals with marked periodic corpora lutea were given an i. m. injection of 0.5 mg cloprostenol. The eighth day from the administration of the preparation, the ovaries of the cows were excised and, after histological processing in a simultaneous series in a 4mm interval, the preparations were subjected to qualitative and quantitative microscopic evaluation. The structure of non-atretic and atretic follicles was described in different stages of the atretic process. The lymphoid cells of atretic follicles were observed to penetrate into the granulosa membrane. A multiplication of non-atretic tertiary follicles was observed after the administration of cloprostenol. This multiplication was more pronounced on the right ovary where the preceding ovulation had taken place (P less than 0.01). The treated animals, compared with the controls, showed a significant multiplication of tertiary follicles at early atresia and at total collapse atresia (P less than 0.001), whereas the number of follicles with contractive atresia showed a significant decrease (P less than 0.001). The results suggest that cloprostenol can influence follicle population mostly through the stimulation of the growth and ripening of tertiary follicles; its modulation effect seems manifest itself in cooperating relation with gonadotrophic hormones, mainly with the follicular secondary hormone (FSH), in the theory of the complex effect of proteohormones .