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1.
Reciprocal embryo transfer between repeat breeder and virgin heifers--an experimental model 总被引：1，自引：0，他引：1
The aim of the study was to evaluate the importance of mother-concaptus relationships for the elevated embryonic loss in repeat breeder heifers. Embryos were collected by non-surgical technique, classified and transferred surgically or non-surgically to synchronized, inseminated recipients. The embryos were transferred to the uterinehorn contralateral to the corpus luteum. The embryos were transferred from repeat breeder heifers (RBH) to virgin heifers (VH) or from VH to RBH. After slaughter 4 weeks after transfer there was no difference in emhryonic survival between heifer categories following transfer or insemination. In some animals degenerated foetal membranes were found in the nonpregnant horn. The study indicates embryonic morphology rather than the category of donor or recipient as influencing the embryonic survival rate.Key words: embryo, embryonic death, embryo transfer, repeat breeder 相似文献
2.
Forty-two repeat breeder heifers (RBH) and 27 virgin heifers (VH) were used in the study. The breeding history and the occurrence of chromosomal aberrations were investigated in the RBH. The genital tracts of the RBH and the VH were investigated at slaughter 3 to 35 days after artificial insemination and/or embryo transfer for the presence of morphological and histological changes. According to AI data the mean number of inseminations per RBH in the herd of origin was 4.9 and 110 interservice intervals out of 141 calculated were normal (17–24 days) or twice normal (34–48 days). Two RBH out of 28 investigated demonstrated the 1/29 translocation. The post mortem examination revealed corpus lutea and follicles normal for the stage of the cycle in all animals. In three RBH abnormalities of the uterus or cervix were found. A higher incidence of cystic glands and of focal accumulation of erythrocytes and lymphocytes in the endometrium was found in the RBH than in the VH (P ≤ 0.05). The relation between the embryonic survival and the histological alterations of the uterus was not significant.It is suggested that errors in heat detection, abnormal karyotypes and morphological defects of the genital tract play a minor role in the repeat breeding complex in heifers. 相似文献
3.
H Awasthi F Saravia H Rodríguez‐Martínez R Båge 《Reproduction in domestic animals》2010,45(5):e194-e198
One of the main sources of repeat breeding in dairy cattle, caused by fertilization failure or early embryonic death, is metabolic stress during lactation. Nutrition seems also to play a role when the condition is seen in heifers, where oocyte cytoplasmic maturation is impaired. To determine whether over conditioning affects oocyte morphology, immature oocytes were collected by ovum pick‐up (OPU) twice weekly during 5 weeks from three over‐conditioned repeat breeder dairy heifers (RBH) and two normal virgin heifers (VH, controls) of the Swedish Red breed, monitored by body weight and condition. Oocyte quality was assessed under stereomicroscope and further examined by transmission electron microscope for accumulation of cytoplasmic lipid deposits. After OPU, the RBH yielded more low quality oocytes (60% vs 52% for VH, p = 0.14). The relative occupancy of osmophilic lipid droplets in the cytoplasm was higher in oocytes of bad quality compared with good ones, especially in RBH (p = 0.08) but also in VH (p = 0.11). Moreover, the oocytes from over‐conditioned RBH showed higher amounts of cytoplasmic lipid deposits both in good (p = 0.14) and, even more prominent, in bad quality oocytes (p = 0.06). Such accumulation of lipid droplets may imply increased sensitivity to oxidative stress, hinder cytoplasmic maturation and lead to subfertility, as accounted in over‐conditioned repeat breeders of the Swedish Red breed. 相似文献
4.
Hormonal asynchronies during oestrus, related to the presence of suprabasal plasma-progesterone (P4) concentrations and a delayed ovulation, interfere with the fertility of repeat-breeder heifers (RBH). Since tubal dysfunction can occur in connection with hormonal asynchronies and constrained availability of fertile spermatozoa at the time of ovulation, the present study tested the hypothesis that frequent sperm deposition from onset of oestrus to ovulation may improve pregnancy rates in RBH. Five RBH and five virgin heifers (VH; controls) were repeatedly artificially inseminated (AI) at 6 h intervals from onset of oestrus to spontaneous ovulation. Hormone analyses revealed suprabasal P4 concentrations and a delay in the occurrence of the luteinising hormone (LH) surge, but a normal cortisol profile in RBH. Compared with controls, RBH presented longer interval from onset of oestrus to ovulation, and therefore, received more AIs. Pregnancy rates in RBH reached control levels (60%; NS), indicating that the hypothesis might be correct. Pregnancy rates in VH were below the expected range, presumably attributed to a deleterious influence of the frequent handling. The study suggests that pregnancy rates can be improved in RBH by frequent AI in relation to spontaneous ovulation. However, this practice of repeated manipulations, while seeming not to show adverse effects, lacks practicality for routine use. 相似文献
5.
Bhupender Singh Fernando Saravia Renée B?ge Heriberto Rodríguez-Martínez 《Acta veterinaria Scandinavica》2005,46(1):1-12
Hormonal asynchronies during oestrus, related to the presence of suprabasal plasma-progesterone (P4) concentrations and a delayed ovulation, interfere with the fertility of repeat-breeder heifers (RBH). Since tubal dysfunction can occur in connection with hormonal asynchronies and constrained availability of fertile spermatozoa at the time of ovulation, the present study tested the hypothesis that frequent sperm deposition from onset of oestrus to ovulation may improve pregnancy rates in RBH. Five RBH and five virgin heifers (VH; controls) were repeatedly artificially inseminated (AI) at 6 h intervals from onset of oestrus to spontaneous ovulation. Hormone analyses revealed suprabasal P4 concentrations and a delay in the occurrence of the luteinising hormone (LH) surge, but a normal cortisol profile in RBH. Compared with controls, RBH presented longer interval from onset of oestrus to ovulation, and therefore, received more AIs. Pregnancy rates in RBH reached control levels (60%; NS), indicating that the hypothesis might be correct. Pregnancy rates in VH were below the expected range, presumably attributed to a deleterious influence of the frequent handling. The study suggests that pregnancy rates can be improved in RBH by frequent AI in relation to spontaneous ovulation. However, this practice of repeated manipulations, while seeming not to show adverse effects, lacks practicality for routine use. 相似文献
6.
Embryos were collected from repeat breeder heifers and virgin heifers seven days after insemination, classified and transferred to the uterine horn contralateral to the corpus luteum of synchronised inseminated recipients. Altogether 35 transfers were performed, all reciprocally between repeat breeder heifers and virgin heifers. The recipients were slaughtered either 16 to 17 days or 32 to 35 days after insemination. The survival rate of the native embryos was lower among the repeat breeder heifers than among the virgin heifers both at 16 to 17 days (six of nine vs six of six) and at 32 to 35 days (three of 10 vs seven of 10) after insemination. A higher proportion of embryos transferred from repeat breeder heifers to virgin heifers than from virgin heifers to repeat breeder heifers survived to days 16 to 17 (five of six vs two of nine), while the same proportion of embryos survived to days 32 to 35 (two of 10) in both heifer categories. The results suggest that the uterine environment in repeat breeder heifers is suboptimal for the support of normal embryonic development. 相似文献
7.
A Cytogenetic Study of Repeat-breeder Heifers and Their Embryos 总被引：1，自引：1，他引：0
King WA Linares T 《The Canadian veterinary journal. La revue veterinaire canadienne》1983,24(4):112-115
Twenty-three Swedish Red and White, Swedish Friesian and crossbred repeat-breeder heifers and 15 day 7 embryos produced by 11 of these heifers were subjected to cytogenetic analysis. Three heifers were found to have abnormal karyotypes; two were heterozygous for the 1/29 translocation, and one was an X-trisomy. Chromosomal anomalies which might account for embryonic death and subsequent repeat-breeding could not be detected in the embryos, however, seven out of the 15 could not be karyotyped due to the lack of cells in metaphase. The possibility of chromosomal anomalies in these embryos could not be ruled out. Three embryos produced by the heifers carrying the translocation were among those which lacked cells in mitosis. Two unfertilized ova were recovered from the X-trisomy heifer suggesting that fertilization failure rather than embryonic death was the cause of repeat-breeding. In the light of this study and similar studies in other species, it is suggested that investigations at earlier stages of development are needed. 相似文献
8.
Conception Rates after AI in Swedish Red and White Dairy Heifers: Relationship with Progesterone Concentrations at AI 总被引：1，自引：0，他引：1
R Båge 《Reproduction in domestic animals》2003,38(3):199-203
Blood samples were collected from 211 dairy heifers at the time of field insemination [artificial insemination (AI)]. Heifers were defined as either first‐service heifers (n = 91) or third to eigth‐service heifers [presumed (third AI, n = 60)] or well‐defined repeat breeders (greater than the fourth AI, n = 60). Plasma progesterone concentrations at AI were evaluated in relation to oestrous behaviour at AI and conception rates post‐AI. Conception rates after third AI were good, but conception rates decreased markedly after fourth AI and onwards. Those heifers that did not become pregnant after AI had significantly higher basal progesterone concentrations (>0.5 nmol/l) at AI, so‐called suprabasal concentrations, compared with those which conceived after AI (irrespective of the number of AI practised). Relative risk for repeat breeding was 58% after AI performed at suprabasal progesterone concentrations, while it was 42% at basal (0.5) progesterone concentrations. Results from this field study confirm results obtained in earlier controlled studies of repeat‐breeder heifers (RBH), indicating that the current definition of repeat breeding should be retained. Analysis of suprabasal progesterone concentrations could be considered as a tool for identification of RBH, provided that heat detection and AI timing are optimal. Besides considering the direct costs involved in repeat breeding, it remains to be determined whether it would be economically beneficial to identify and exclude RBH from the breeding population. 相似文献
9.
对５头屡配不孕育成牛的临床与内分泌学研究发现，有的发情持续时间和发情排卵间隔时间较长。经适时追加授精，在１个情期内，４头实验牛中有３头受孕。实验牛在非授精发情周期和授精发情周期的外周血浆Ｐ４和ＰＧＦＭ无异常变化，说明这些牛的屡配不孕与管理因素有关 相似文献
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11.
1. The present study was carried out to determine whether primordial germ cells isolated from embryonic blood can enter the bloodstream and successfully migrate to the germinal ridges of recipient embryos after transfer to stage X blastoderms, and also whether they can differentiate into blood cells, as is suggested in mice. 2. Primordial germ cells were transfected in vitro by lipofection and then transferred to stage X blastoderms. The introduced GFP gene was efficiently expressed in the gonads of 6-d incubated embryos. 3. Freshly collected primordial germ cells were transferred to stage X blastoderms. The fate of the transferred primordial germ cells was traced by detecting the single nucleotide polymorphism in the D-loop region of the mitochondrial DNA in White Leghorn and Barred Plymouth Rock chickens used in this study. The transferred donor primordial germ cell-derived cells were detected in the gonads, but not in the blood cells, of 17-d incubated embryos by PCR. 4. This procedure for primordial germ cell manipulation could provide a novel method of producing germline chimaeric chickens. 5. In conclusion, our findings indicate that primordial germ cells isolated from embryonic blood can migrate to the germinal ridges of recipient embryos after being transferred to stage X blastoderms. Although these transferred primordial germ cells differentiated into germ cells, no differentiation into blood cells was observed. 相似文献
12.
A detailed clinical-endocrine investigation was performed in 6 repeat breeder heifers (RBH) with the aim being to ascertain whether endocrine asynchronism exists at luteal regression and during early pregnancy. The heifers were first studied during an open cycle and then after insemination when 3 heifers became pregnant. Circulating plasma levels of PGF2 alpha metabolite were measured every 2nd h, while progesterone (P4) levels were measured every 6th h. The oestrous period and intervals between the onset of oestrus and ovulation were relatively longer, compared with what is normally seen in heifers. Plasma levels of P4 at the onset of oestrus were higher than normal, but it was concluded that the plasma levels of PGF2 alpha metabolite and P4 in RBH at luteal regression and early pregnancy were normal. 相似文献
13.
Schernthaner W Wenigerkind H Stojkovic M Palma GA Mödl J Wolf E Brem G 《Zentralblatt für Veterin?rmedizin. Reihe A》1999,46(1):33-37
Thirty-six cows (21 Simmental, 5 Holstein-Frisian, 5 Brown Swiss and 5 Charolais) with high genetic superiority were punctured by ultrasound-guided follicle aspiration within the last 18 months for 503 times under equal conditions. Follicle aspiration was done twice per week. Most of the donor cows suffered from several disturbances of fertility. On average, 5 oocytes per session were collected. After in vitro maturation (IVM), fertilisation (IVF) and culture (IVC), 0.8 embryos per puncture session were transferred. After evaluation of the embryos by morphological criteria, these embryos were transferred to heifers that were oestrus synchronised (2.0 ml Estrumate i.m.) seven days after onset of oestrus. On day 21 after onset of oestrus the progesterone level in plasma was determined by radioimmunoassay. The pregnancy control was performed by ultrasound on day 35. After transfer of 397 embryos (to synchronised heifers), 125 pregnancies were established. Comparison of the different breeds and donor cows revealed significant differences in the number of oocytes recovered, embryos produced and pregnancies established. Transfer of embryos with insufficient morphological quality resulted in increased rates of embryonic loss between day 21 and day 35. 相似文献
14.
Ideta A Hayama K Urakawa M Jung YG Lim KT Lee WY Song HB Aoyagi Y 《The Journal of reproduction and development》2007,53(5):1015-1021
In this study, we first attempted to determine whether the timing of artificial insemination affects the sex ratio of seven-day-old embryos in superovulated Holstein heifers. The superovulatory treatment consisted of eight decreasing doses of FSH for 4 days and 2 doses of PGF(2alpha) given with the last two doses of FSH. The superovulated heifers were given a GnRH analogue 48 h after the first PGF(2alpha) treatment and were artificially inseminated 48 h (n=10) or 56 h (n=8) after the first PGF(2alpha) treatment. There were no significant differences in the percentages of unfertilized ova and transferable embryos (grades 1 to 3) between the two groups. The proportions of female grade 1 embryos did not significantly differ from the expected ratio of 50:50 (49.3% at 48 h and 52.5% at 56 h). We then compared the estrous behavior and superovulatory responses of the heifers with a proportion of female embryos of 50% or less (n=7, Low group) to those of the heifers with a proportion of female embryos of more than 50% (n=9, High group). The Low group had a longer duration of estrus and a higher superovulatory response than the High group. These findings offer little encouragement for prediction of the population of female embryos collected from superovulated heifers. Further studies are necessary to evaluate to what degree maternal hormone levels are related to estrus duration and sex ratio. 相似文献
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In vitro studies of lens formation in chick embryo have suggested the action of two factors leading the lens induction in the cephalic ectoderm in the absence of optic vesicle: preliminary instructive specific stimulus (homotypic endo-mesoderm) and permissive unspecific stimulus (heterotypic mesenchymes). In order to detect the true capacities of tissues that exert this influence in the cultural condition, series of in vitro experiments were planned. Exclusion experiments: explants including presumptive lens ectoderm were cultured previous to a progressive exclusion of adjacent tissues to trigger lens formation (endoderm, mesoderm and neural tissue), from stage 1 to 7 of HAMBURGER/HAMILTON. Recombinant experiments: Recombinations of caudal epiblast with cephalic hypoblast from blastoderms stages 3, 4 and 5; and recombinations of cardiac mesoderm stage 7 with trunk ectoderm stage 11, were cultured in close association. Lens and lentoids were formed in the presumptive lens ectoderm, even when endoderm, neural tissue and optic vesicle were excluded, but always in presence of subjacent mesoderm. Observation of cephalic epiblast after to be separated mechanically from the underlying tissues showed that the presumptive cardiac mesoderm remains in contact with the epiblast. Beside the cardiac area was capable of forming lens bodies in contact with the trunk ectoderm. It was concluded that the cardiac mesoderm is able to exert a instructive specific stimulus and a permissive unspecific stimulus during in vitro lens formation. 相似文献
18.
Day 7 bovine embryos were microsurgically bisected and replaced into surrogate zonae pellucidae. They were fixed immediately after bisection and at various intervals of in vitro incubation at 35 °C in modified Dulbecco's medium. At the light microscopical level, the bisected embryos restored the prebisection morphology within 30 min. after splitting. The electron microscopy confirmed these findings, suggesting that day 7 bovine demi-embryos for transfer purposes, should be cultured for 30 min before morphologically evaluated. Eleven pairs of bisected day 7 bovine embryos were transferred to 11 synchronized heifers. The recipient heifers were slaughtered at day 15, and the recovered embryos evaluated. Nine of the demi-embryos developed to morphologically, normal spherical to elongated, embryos. 相似文献
19.
Barth AD Bowman PA Bo GA Mapletoft RJ 《The Canadian veterinary journal. La revue veterinaire canadienne》1992,33(1):31-39
Seven experiments were done in feedlot heifers to determine the importance of various degrees of narrowness of the sperm head on fertility in feedlot heifers. Frozen semen used in these experiments was selected to be normal in all respects except for very high numbers of a single specific type of sperm head aberration. Semen with the sperm aberration in question and control semen were selected to be as similar as possible in dose and postthaw viability so that differences in fertility would be attributable to the morphological variant under study. Fertilization rates were determined by collecting embryos from the reproductive tracts of superovulated heifers which had been slaughtered seven days after insemination. Pregnancy rates and rates of embryonic loss were studied in estrus-synchronized heifers by repeated transrectal ultrasound examinations from day 22 to day 55 after insemination. Reproductive tracts were collected and examined after slaughter at 60 days postinsemination.
The combined results of these experiments show that a moderate degree of sperm head narrowness, in the absence of other seminal signs of a disturbance of spermatogenesis, is not detrimental to fertility. However, extreme narrowness of the postacrosomal region of the sperm head of most spermatozoa, as was found in two bulls without other seminal signs of a disturbance of spermatogenesis, resulted in significantly reduced fertility. The data suggest that, although a decision between normal and abnormal sperm morphology may contain a degree of subjectivity, of the defects studied only sperm with extreme narrowness of the post-acrosomal region are likely to reduce fertility.
相似文献20.
Lee W Song K Lim K Lee S Lee B Jang G 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2012,74(2):167-174
The aim of this study was to investigate the influence of key parameters (donor parity, milk production, post-parturient day, season and milk recording data) associated with efficiency of embryo recovery (ER) in Holstein cattle. Elite Holstein cows and heifers were selected for ER, while Holstein heifers were used as recipients. The numbers of transferable embryos (TEs) produced were not significantly different when analyzed in terms of donor parity, milk production, postparturient day and season. However, the numbers of TEs were significantly increased when the milk protein (%; P)/fat (%; F) ratio was over 0.95 and/or the milk urea nitrogen (MUN) was between 12 and 18 dl/ml. The results from ET showed no differences in pregnancy rates among Holstein heifers receiving other types, developmental stage codes and quality grades of embryos. The mean interval from ER to artificial insemination was 60.6 days. Moreover, 19 offspring that had milk recording data showed a similar milk yield performance to that of the donor cows. In conclusion, this study showed that in Holstein cows, embryos were recovered and transferred and resulted in production of viable calves. Furthermore, P/F ratio and MUN could be candidate indicators for selection of high-efficiency donor cows. 相似文献