Home About us Contact
|
Home About us Contact | ||
|
|
||
Oestrus Cycle (oestrus + cycle)
Selected AbstractsVaginal and Cervical Anatomic Modifications During the Oestrus Cycle in Relation to Transcervical Catheterization in the Domestic CatREPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2004D Zambelli Contents In a previous study we observed that it is possible to reach the cervix in all queens with a 1 mm diameter probe only. So, we developed both a new technique and a catheter (1 mm diameter) to allow transcervical insemination [Zambelli and Castagnetti 2001]. The aims of this study were to investigate vaginal and cervical anatomic modifications during the various stages of the oestrus cycle and to test the previously described technique of transcervical catheterization during the various stages of the oestrus cycle. In experiment 1, silicon impression moulds were obtained from the reproductive tracts of 21 queens' cadavers and vaginal and cervical measures were taken. The results showed that there are some significant anatomic modifications during the various stages of the oestrus cycle in vaginal and cervical anatomy, principally related to the dorsal medial fold increase induced by the follicular phase. In experiment 2, transcervical catheterization was attempted in 95 queens at various stages of oestrus cycle both during reproductive and non-reproductive season. After catheterization, methylene blue solution was injected through the cervical catheter. Successful catheterization was assessed during surgery, when colour was observed in the uterine horns. It was possible to perform transcervical catheterization during non-reproductive season in 16 of 20 anoestrus queens and in 12 of 15 induced oestrus queens; during reproductive season in nine of 21 interoestrus queens, in eight of 13 dioestrus/pregnancy queens, in four of 18 oestrus queens and in seven of eight queens in first oestrus during lactation. [source] Effects of Gonadotropins on In Vitro Maturation and of Electrical Stimulation on Parthenogenesis of Canine OocytesREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2010BS Kim Contents The objective of this study was to determine the effects of gonadotropins on in vitro maturation (IVM) and electrical stimulation on the parthenogenesis of canine oocytes. In experiment I, cumulus oocyte complexes were collected from ovaries at a random phase of the oestrus cycle and cultured on maturation medium treated with hCG or eCG for 48 or 72 h. There were no significant differences in the effects on the metaphase II (MII) rate between the hCG and eCG treatment groups over 48 h (5.4% vs 5.5%). The MII rate in the co-treatment group of hCG and eCG for 48 h was higher than in each hormone treated group (15.5%, p < 0.05). In experiment 2, the parthenogenetic effect on oocyte development, at various electrical field strengths (1.0, 1.5, 2.0 kV/cm DC) for 60 or 80 ,s with a single DC pulse after IVM on the co-treatment of hCG and eCG, was examined. The rate of pronuclear formation (37.1%) in electrical activation at 1.5 kV/60 ,s without cytochalasin B (CB) was higher than that of oocytes activated in the other groups (p < 0.05). However, we did not observe the cleavage stages. Also, CB did not influence parthenogenesis of canine oocytes. The results showed that the pronucleus formation rate, indicative of the parthenogenesis start point, could be increased by electrical stimulation. Therefore, these results can provide important data for the parthenogenesis of canine oocytes and suggest the probability of parthenogenesis in canines. [source] The Role of the Endometrium in Endocrine Regulation of the Animal Oestrous CycleREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2008T Krzymowski Contents A critical analysis of the results of research in the function of the endometrium was carried out and a view point presented. The role of the endometrium in endocrine regulation of the oestrus cycle can be summarized as follows: 1. The transfer of prostaglandin F2, (PGF2,) from the uterus to an ovary, which causes luteolysis, occurs mainly via the lymphatic pathways. 2. The system of retrograde transfer of PGs enables PGF2, and PGE2 to reach the myometrium and endometrium with arterial blood at high concentration. In the luteal phase, PGF2,, together with the increasing concentration of progesterone, constricts the arterial vessels of the uterus; in the follicular phase and in early pregnancy, PGE2 together with oestrogen and embryonic signals, relaxes the arterial vessels. In addition, this system protects the corpus luteum from premature luteolysis during the cycle and luteolysis during early pregnancy. 3. In days 10,12 of the cycle, the blood flow in the uterus decreases by 60,70% in pigs and around 90% in sheep. This causes ischaemia and local hypoxia confirmed by the presence of hypoxia inducible factor and thus remodelling of the endometrium commences. 4. The pulsatile elevations in PGF2, concentration occurring in the blood flowing out of the uterus during the period of luteolysis and the next few days, do not result from increased PGF2, synthesis as suggested in numerous studies. They are the effect of excretion of PGF2, and its metabolites together with lymph and venous blood and tissue fluids in which prostaglandin accumulates. [source] Number of Follicular Waves and Their Effect on Pregnancy Rate in the CowREPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2005HA Çelik Contents In the study, the relationship of follicular growth waves, oestradiol and pregnancy rates were investigated during oestrus cycle in cows. A total of 22, Brown Swiss cows (3,5 years old) were used for the study. The ovaries of animals were examined from sixth day of cycle to next oestrus by ultrasound. The follicles that were present in the ovarium were recorded. Follicular growth was observed every day by means of ultrasound examination. The blood samples were taken for analysis of oestradiol simultaneously with ultrasound examinations. The oestrus animals were inseminated. Each animal that inseminated was examined by ultrasound on day 28 after insemination for pregnancy diagnosis. Two follicular growth waves were observed in nine of 22 (40.9%), three waves in 13 of 22 (59.1%) animals. The oestradiol was found in the same concentration but in different release patterns between two and three waves animals. Pregnancy rate in cows with three and two follicular waves did not differ. In conclusion, emergence of three waves of follicular growth was higher in Brown Swiss cows, the analysis of oestradiol could be used for determination of the wave numbers and the animals with different waves may have had the same pregnancy rates. [source] Second Oestrus Synchronization and Precocious Embryo Viability after Puberty Induction in Gilts by the Use of Gonadotrophin TreatmentREPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2005V Do Lago Contents The use of exogenous gonadotrophins in puberty inducement and ovulation synchronization is a technique that has a positive influence on the management of swine. The purpose of this study was to verify the effects of a second gonadotrophin treatment [equine chorionic gonadotrophin (eCG) and luteinizing hormone (LH), intramuscularly (i.m.)] upon the second oestrus synchronization and fertility in gilts. Seventy-one NAIMA® (Pen Ar Lan) gilts had their first oestrus (puberty inducement) induced by a hormonal treatment (eCG and LH). Then, they were randomly distributed into two treatments, with (T1) and without (C) gonadotrophin treatment at the second oestrus. The animals were fed with a single ration (16% of crude protein and 3286.73 kcal ME/kg), and timed artificial insemination performed at the second oestrus. Gilts were slaughtered for embryo recovery and ovary examination about 5 days after insemination. There was no evidence of a difference in the percentage of the second oestrus expression (T1 , 90.90% and C , 86.84%), the duration of the oestrus cycle (T1 , 19.62 ± 0.82 days and C , 19.67 ± 4.14 days), the percentage of follicular cysts (T1 , 15.15% and C , 18.42%) and number of ovulations (T1 , 14.60 ± 5.7 and C , 13.23 ± 4.8) between treatments (p > 0.05). However, the hormonal treatment (T1) showed minor oestrus dispersion and embryo viability (T1 , 8.4 ± 5.6 and C , 11.2 ± 4.6) (p < 0.05). These results indicate that the better synchronization and expression of the second oestrus when using gonadotrophins (eCG and LH) is followed by a lower embryo viability, which is probably the consequence of the heterogeneous follicle recruitment during the injection of eCG. [source] Ultrasonography and Cystic Hyperplasia,Pyometra Complex in the BitchREPRODUCTION IN DOMESTIC ANIMALS, Issue 3 2004E Bigliardi Contents Cystic endometrial hyperplasia,pyometra complex is the most frequent and important endometrial disorder encountered in bitches. The pathogenesis of the disease is related to the activity of progesterone [Feldman and Nelson, Canine and Feline Endocrinology and Reproduction (1996) W.B. Saunders, Philadelphia]. Cystic endometrial hyperplasia (CEH) is an abnormal response of the bitch's uterus to ovarian hormones [De Bosschere et al. Theriogenology (2001) 55, 1509]. CEH is considered by many authors to be an exaggerated response of the uterus to chronic progestational stimulation during the luteal phase of the oestrous cycle, causing an abnormal accumulation of fluid within the endometrial glands and uterine lumen (De Bosschere et al. 2001). The resulting lesions of pyometra are due to the interaction between bacteria and hormones. The aim of this study was to evaluate if transabdominal uterine ultrasonography can be a useful and reliable diagnostic method to confirm Dow's [Veterinary Record (1958) 70, 1102] and De Bosschere's histopathological classification of CEH,pyometra complex. The study was carried out on 45 bitches with pyometra, 10 purebreeds and 35 crossbreeds, 1,15 years old, 20% of which had whelped at least once. None of these animals had received exogenous oestrogen or progesterone treatment. On admission the 45 animals were in the luteal phase of the oestrus cycle. Clinical signs, blood parameters, uterine ultrasonography, bacterial swabs and uterine histopalogical results were recorded. Results suggest that ultrasonographic examination is a useful and reliable tool for the diagnosis of cystic endometrial hyperplasia. [source] Vaginal and Cervical Anatomic Modifications During the Oestrus Cycle in Relation to Transcervical Catheterization in the Domestic CatREPRODUCTION IN DOMESTIC ANIMALS, Issue 2 2004D Zambelli Contents In a previous study we observed that it is possible to reach the cervix in all queens with a 1 mm diameter probe only. So, we developed both a new technique and a catheter (1 mm diameter) to allow transcervical insemination [Zambelli and Castagnetti 2001]. The aims of this study were to investigate vaginal and cervical anatomic modifications during the various stages of the oestrus cycle and to test the previously described technique of transcervical catheterization during the various stages of the oestrus cycle. In experiment 1, silicon impression moulds were obtained from the reproductive tracts of 21 queens' cadavers and vaginal and cervical measures were taken. The results showed that there are some significant anatomic modifications during the various stages of the oestrus cycle in vaginal and cervical anatomy, principally related to the dorsal medial fold increase induced by the follicular phase. In experiment 2, transcervical catheterization was attempted in 95 queens at various stages of oestrus cycle both during reproductive and non-reproductive season. After catheterization, methylene blue solution was injected through the cervical catheter. Successful catheterization was assessed during surgery, when colour was observed in the uterine horns. It was possible to perform transcervical catheterization during non-reproductive season in 16 of 20 anoestrus queens and in 12 of 15 induced oestrus queens; during reproductive season in nine of 21 interoestrus queens, in eight of 13 dioestrus/pregnancy queens, in four of 18 oestrus queens and in seven of eight queens in first oestrus during lactation. [source] The Immunohistochemical Localization of Desmin and Smooth Muscle Actin in the Ovary of the African Giant Rat (Cricetomys gambianus) During the Oestrous CycleANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 1 2010M.-C. Madekurozwa Summary The aim of this study was to describe the distribution of smooth muscle actin and desmin immunopositive cells in the ovary of the giant rat. In addition, the study describes the morphological changes in the ovary of this species during the oestrous cycle. Healthy secondary and tertiary follicles dominated the ovary during pro-oestrus and oestrus. The theca externa of the tertiary follicles was immunopositive for smooth muscle actin, but immunonegative for desmin. Oestrus was also characterized by the presence of corpora haemorrhagica, which had an outer layer of smooth muscle actin immunopositive cells. Differentiating corpora lutea were observed during metoestrus. A further notable feature of the ovary during metoestrus was the presence of numerous atretic secondary and tertiary follicles. In the later stages of atresia, the follicles were infiltrated by desmin and smooth muscle actin immunopositive cells. Dioestrus was characterized by the presence of non-regressing and regressing corpora lutea. Immunostaining for smooth muscle actin was demonstrated in the enclosing layer of the corpora lutea, as well as in the tunica media of blood vessels within the corpora lutea. The results of this study have shown that morphological changes in the ovary of the giant rat during the oestrus cycle are similar to those of laboratory rodents. Furthermore, the results of the immunohistochemical study indicate that the perifollicular distribution of desmin and smooth muscle actin cells changes during follicular development and atresia. [source] Effects of intensive harvesting on moose reproductionJOURNAL OF APPLIED ECOLOGY, Issue 3 2000Catherine Laurian Summary 1.,It has been hypothesized that a balanced adult sex ratio is necessary for the full participation of ungulate females in reproduction and therefore high productivity. We tested this general hypothesis by combining two complementary approaches. 2.,First, using telemetry (n = 60) and annual aerial censuses between 1995 and 1998, we compared two moose Alces alces populations in Quebec, Canada, one non-harvested and the other subject to intensive sport harvesting from the end of September to mid-October. We tested the following predictions for the harvested population: (i) females increase movements and home ranges during the mating period; (ii) the mating system is modified, with the appearance of groups of one male and many females; (iii) subadult males participate in reproduction; (iv) the mating period extends over two to three oestrus cycles; (v) the calving period extends over several months; and (vi) productivity declines. 3.,Daily movements and home range sizes during the mating period did not differ between harvested and non-harvested populations. Most groups observed were male,female pairs. Subadult males (1·5,2·5 years old) were only observed with females in the harvested population. Mating and calving periods did not differ between populations. The proportion of females that gave birth and the number of calves produced were also comparable in the two populations. 4.,Secondly, we also assessed the existence of a relationship between population productivity and percentage of males in various management units of the province of Quebec that were characterized by a wide range in sex ratios. Contrary to prediction (vi), the number of calves per 100 adult females was not related to the percentage of adult males in the population. 5.,The participation of young adult males (subadults) in reproduction in our harvested population may have compensated for the lower percentage of adult males, and thus productivity was unaffected. We therefore reject the hypothesis that intensive harvesting, at least at the level we observed, affects reproduction and population productivity. 6.,As there are some uncertainties regarding the long-term effects of high hunting pressure, however, managers should favour sex ratios close to levels observed in non-harvested populations. [source] | ||||||||||