RESUMO
The objective of this study was to assess the quality of a diagnostic model for the detection of hyperketonemia in early lactation dairy cows at test days. This diagnostic model comprised acetone and ß-hydroxybutyrate (BHBA) concentrations in milk, as determined by Fourier transform infrared (FTIR) spectroscopy, in addition to other available test-day information. Plasma BHBA concentration was determined at a regular test day in 1,678 cows between 5 and 60 d in milk, originating from 118 randomly selected farms in the Netherlands. The observed prevalence of hyperketonemia (defined as plasma BHBA ≥1,200 µmol/L) was 11.2%. The value of FTIR predictions of milk acetone and milk BHBA concentrations as single tests for hyperketonemia were found limited, given the relatively large number of false positive test-day results. Therefore, a multivariate logistic regression model with a random herd effect was constructed, using parity, season, milk fat-to-protein ratio, and FTIR predictions of milk acetone and milk BHBA as predictive variables. This diagnostic model had 82.4% sensitivity and 83.8% specificity at the optimal cutoff value (defined as maximum sum of sensitivity and specificity) for the detection of hyperketonemia at test days. Increasing the cutoff value of the model to obtain a specificity of 95% increased the predicted value of a positive test result to 56.5%. Confirmation of test-positive samples with wet chemistry analysis of milk acetone or milk BHBA concentrations (serial testing) improved the diagnostic performance of the test procedure. The presented model was considered not suitable for individual detection of cows with ketosis due to the length of the test-day interval and the low positive predictive values of the investigated test procedures. The diagnostic model is, in our opinion, valuable for herd-level monitoring of hyperketonemia, especially when the model is combined with wet chemistry analysis of milk acetone or milk BHBA concentrations. By using the diagnostic model in combination with wet chemistry milk BHBA analysis, 84% of herds were correctly classified at a 10% alarm-level prevalence. As misclassification of herds may particularly occur when only a limited number of fresh cows are sampled, we suggest using prevalence estimates over several consecutive test days to evaluate feeding and management practices in smaller dairy farms.
Assuntos
Ácido 3-Hidroxibutírico/análise , Acetona/análise , Doenças dos Bovinos/diagnóstico , Cetose/veterinária , Leite/química , Animais , Bovinos , Feminino , Humanos , Cetose/diagnóstico , Paridade , Estações do Ano , Sensibilidade e Especificidade , Espectroscopia de Infravermelho com Transformada de Fourier/veterináriaRESUMO
The objective of this study was to evaluate a new superovulation procedure with oFSH after temporary suppression of the endogenous LH surge by norgestomet followed by administration of GnRH, to collect bovine oocytes and embryos at specific developmental stages. Since 1999, our research group applies this superovulation procedure with controlled release of the endogenous LH surge. The objective of this study is to verify if this procedure is reliable for collection of oocytes and embryos at specific time points of development and if it produces a sufficient number of both oocytes and embryos of good quality. This procedure was validated regarding to hormonal characteristics, superovulatory response and both oocyte and embryo yield at different times of in vivo development. The results demonstrate that the procedure used to control the occurrence of the pre-ovulatory LH surge was effective in 92% of the animals (n = 238) and even in 99% of the animals the oocytes and embryos were collected at the intended stage of development. The superovulatory response and both oocyte, embryo yield and quality were similar to the average yield in Europe reported by Association Européenne de transfert embryonnaire (AETE). In conclusion, this superovulation procedure provides a valid tool to collect oocytes and embryos at specific time points of development.
Assuntos
Bovinos/fisiologia , Estradiol/análogos & derivados , Hormônio Foliculoestimulante/farmacologia , Pregnenodionas/farmacologia , Prostaglandinas F Sintéticas/farmacologia , Superovulação , Animais , Bovinos/embriologia , Preparações de Ação Retardada , Estradiol/administração & dosagem , Estradiol/farmacologia , Sincronização do Estro/métodos , Feminino , Hormônio Foliculoestimulante/administração & dosagem , Inseminação Artificial/veterinária , Masculino , Oócitos/fisiologia , Pregnenodionas/administração & dosagem , Prostaglandinas F Sintéticas/administração & dosagem , OvinosRESUMO
The aim of this study was to determine the optimal maturation culture period of ovum pick up (OPU)-derived cumulus oocytes complexes (COCs) in relation to their developmental capacity. Embryo production, embryo cryotolerance, post-transfer embryonic survival and calf characteristics such as gestation length, birthweight and sex ratio were investigated. This retrospective study covers the analyses of ovum pick up -in vitro production and calving results from a commercial programme that took place between March 1994 and September 2004. Donors were both heifers (of which approximately 90% pregnant) and cows (of which approximately 10% pregnant). Embryo production analyses were based on 7800 OPU sessions conducted from January 1995 until January 1999. Analyses of calving rate were based on 13 468 embryo transfers performed during January 1995 until May 2002. Analyses on calf characteristics were based on 2162 calves born between March 1994 and September 2004. The in vitro maturation culture period ranged from 16 to 28 h. The mean production rate of transferable embryos was 16.5% (1.2 embryos per OPU session). Length of maturation culture period did not affect the production of transferable embryos. Mean calving rate was 40.9% and 38.7% for fresh and frozen/thawed embryos, respectively. Calving rate was not affected by the maturation culture period. Mean birthweight, gestation length and proportion of male calves were 46 kg, 281.9 days and 52.8%, respectively. Maturation culture period did not affect these variables. In conclusion, this study shows that the in vitro maturation culture period within the range of 16-28 h does not affect in vitro embryo production, embryo cryotolerance, post-transfer embryonic survival and calf characteristics, suggesting that all COC batches collected by OPU on the same day, can be fertilized in one IVF session without a significant loss in the production from oocyte to calf.
Assuntos
Bovinos/fisiologia , Técnicas de Maturação in Vitro de Oócitos/veterinária , Recuperação de Oócitos/veterinária , Oócitos/fisiologia , Animais , Técnicas de Cultura Embrionária/veterinária , Transferência Embrionária/veterinária , Feminino , Fertilização in vitro/veterinária , Técnicas de Maturação in Vitro de Oócitos/métodos , Masculino , Recuperação de Oócitos/métodos , Gravidez , Estudos RetrospectivosRESUMO
Pharmacologically-induced luteolysis or treatment with an antiprogestin in early post-implantation pregnancy in dogs results in asynchronous death and resorption of conceptuses, indicating variable rates of response of individual conceptuses towards progesterone deficiency. This variability also seems to occur in bitches showing pregnancy failure in response to spontaneous luteal deficiency. In a total of 10 beagle pregnancies (two consecutive pregnancies of five bitches), abortifacient treatments beginning on day 24 after ovulation (ov) involved either administration of a progestin antagonist (total of six pregnancies, in three bitches) or a luteolytic regimen of prostaglandin F(2alpha)-analogue together with a dopamine agonist (total of four pregnancies, in two bitches). The outcomes were evaluated in relation to four control pregnancies in two bitches by assay of serum progesterone, prolactin and relaxin at selected time points or within selected time periods, by ultrasound of conceptuses including measurement of uterine blood flow, and parameters of the blood fibrinolytic system including plasma fibrinogen and plasminogen. The process of embryonic death and conceptus resorption was variable in onset and duration both in bitches that received the progesterone antagonist aglepristone (AGLE) and in those under the luteolytic treatment (cloprostenol combined with cabergoline). Pregnancy termination (death of all embryos or foetuses, respectively) occurred as early as day 29 and as late as day 41 after ov in AGLE-treated bitches, and not earlier than day 37 after ov in luteolytic-treatment bitches. Impending embryonic death was not predicted by changes in relaxin concentration, parameters of the fibrinolytic system, or in the perfusion of small uteroplacental vessels.
Assuntos
Prenhez , Progesterona/sangue , Aborto Induzido/veterinária , Aborto Animal , Animais , Cabergolina , Cloprostenol/administração & dosagem , Cloprostenol/farmacologia , Cães , Desenvolvimento Embrionário , Ergolinas/administração & dosagem , Ergolinas/farmacologia , Estrenos/administração & dosagem , Estrenos/farmacologia , Feminino , Gravidez , Prolactina/sangue , Relaxina/sangueRESUMO
In current in vitro production (IVP) systems, oocytes lack in vivo dominant and preovulatory follicular development, which may compromise pregnancy and viability of calves born. When an oocyte sets off in vivo on the road toward fertilization, it contains numerous transcripts and proteins necessary to survive the first few cell cycles of embryonic development. It is not yet known during which period of development the oocyte builds up the store, possibly primarily during the major growth phase of the oocyte, which is completed at the time a follicle reaches the size of 3 mm. Here, we investigated to what extent the later phases of follicular development, such as prematuration in the dominant follicle before the LH surge and ensuing final maturation in the preovulatory follicle, contribute to oocyte competence and development into viable biastocysts. Recent studies on in vivo vs in vitro oocyte maturation employed oocytes from an identical preovulatory development by applying ovum pick-up (OPU) twice (before and 24 h after the LH surge) in each cow treated for superovulation with a controlled LH surge. The embryo recovery rates at Day 7 of IVC after IVF were similar: 44% (97/219) for in vivo- vs 41% (87/213) for in vitro-matured oocytes, which shows that the natural environment during final maturation is not essential for the mere in vitro development of the prematured oocyte beyond the 8- to 16-cell stage. However, in vivo maturation appeared to contribute to the oocyte's quality in a more subtle way, as indicated by a significant increase in the proportion of expanded blastocysts and a more physiological degree of chromosome aberrations of the embryos. In blastocysts derived from in vivo-matured oocytes, 21% of the embryos were mixoploid vs 50% from in vitro-matured oocytes, concomitant with a higher number of cells (96 vs 54 per normal blastocyst). The expression pattern of a set of six developmentally important genes was, however, not significantly altered in blastocysts derived from in vivo-matured oocytes. Certain deviations were observed compared with the levels of entirely in vivo-developed control blastocysts, which suggests that the beneficial effects of in vivo maturation are possibly exerted at initial stages of embryonic development. Prematuration in vivo, occurring in a dominant follicle developing from about 8 mm into the preovulatory follicle, is accompanied by changes in protein synthesis of the cumulus oocyte complex (COC). Presumably, the differentially expressed proteins are involved in equipping the oocyte with further developmental competence. Although we have unraveled some important biochemical and cellular biological features of the oocyte, further research on in vivo processes is essential to improve in vitro embryo production in practice.
Assuntos
Blastocisto/citologia , Bovinos/embriologia , Embrião de Mamíferos/citologia , Oócitos/citologia , Animais , Bovinos/fisiologia , Ciclo Celular , Células Cultivadas , Desenvolvimento Embrionário e Fetal , Feminino , Técnicas In Vitro , Hormônio Luteinizante/metabolismo , Hormônio Luteinizante/farmacologia , Folículo Ovariano/citologia , Folículo Ovariano/fisiologia , SuperovulaçãoRESUMO
Optimization of ovum pick up (OPU) followed by in vitro embryo production (IVP) is strongly driven by the needs of both beef and dairy cattle breeders to enhance genetic improvement. The rapidly growing use of genomic selection in cattle has increased the interest in using OPU-IVP technology to increase the number of embryos and offspring per donor, thus allowing enhanced selection intensity for the next generation. The aim of this study was to optimize embryo production through supplementation of cysteamine during in vitro maturation (IVM) and in vitro culture (IVC) of both slaughterhouse- and OPU-derived oocytes. The effects on embryo production and on embryo cryotolerance, post-transfer embryo survival, and calf characteristics, including gestation length, birth weight, perinatal mortality, and sex ratio were studied. In study 1, immature slaughterhouse-derived cumulus-oocyte complexes (COCs) were matured in IVM medium supplemented with or without 0.1 mM cysteamine, fertilized and cultured for 7 days in 0.5 ml SOFaaBSA. In study 2, cysteamine was present during both IVM (0.1 mM) and IVC (0.01, 0.05, 0.1 mM) from Days 1 to 4. In study 3, OPU-derived COCs were matured in medium supplemented with or without 0.1 mM cysteamine in a 2 × 2 factorial design (OPU week and cysteamine treatment). Embryos were evaluated for stage and grade on Day 7 and, depending on the number of transferable embryos and recipients available, the embryos were transferred either fresh or frozen-thawed at a later date. The presence of cysteamine during IVM significantly increased the embryo production rate with slaughterhouse-derived COCs (24.0% vs. 19.4%). The higher number of embryos at Day 7 was due to an increased number of blastocysts, whereas the distribution of embryos among different quality grades and cryotolerance was not affected. Embryo production rate was negatively affected when cysteamine was present during both the processes of IVM and IVC during Days 1 to 4 of culture (13.2%-19.3% vs. 26.4%). The presence of cysteamine during IVM of OPU-derived COCs also significantly increased the embryo production rate (34.4% vs. 23.4%). The higher number of embryos was again totally due to an increased number of blastocysts, whereas cryotolerance was not affected. The relative increase in embryo production rate was higher with OPU-derived oocytes compared with slaughterhouse-derived COCs (47% vs. 24%). This improvement resulted in a mean of 1.73 transferable embryos per OPU session compared with 1.06 in the absence of cysteamine. The presence of cysteamine did not affect pregnancy rate, gestation length, birth weight, perinatal mortality, and sex of calves born from either fresh or frozen-thawed embryos. This study reported that cysteamine supplementation during IVM greatly improved the efficiency and affectivity of an OPU-IVP program.
Assuntos
Animais Recém-Nascidos/fisiologia , Bovinos , Criopreservação , Cisteamina/farmacologia , Desenvolvimento Embrionário/efeitos dos fármacos , Oócitos/efeitos dos fármacos , Matadouros , Animais , Animais Recém-Nascidos/crescimento & desenvolvimento , Bovinos/embriologia , Bovinos/fisiologia , Sobrevivência Celular , Células Cultivadas , Estudos Cross-Over , Criopreservação/veterinária , Desenvolvimento Embrionário/fisiologia , Feminino , Técnicas de Maturação in Vitro de Oócitos/métodos , Técnicas de Maturação in Vitro de Oócitos/veterinária , Recuperação de Oócitos/métodos , Recuperação de Oócitos/veterinária , Oócitos/fisiologia , Gravidez , Taxa de GravidezRESUMO
Induction of parturition with glucocorticosteroids in cattle is used for research purposes, in diseased or injured pregnant cows, and as a management tool to time parturition. A negative side effect of induction of parturition with glucocorticosteroids is the high incidence of retained placenta that occurs after these calvings. Reaction of the maternal immune system against the 'foreign' foetal membranes contributes to the breakdown of the foetal-maternal attachment. Several studies indicate that failure of this immune assisted detachment increases the occurrence of retained placenta. We hypothesized that retained placenta occurring after induction of parturition with glucocorticosteroids is caused by failure of immune assisted detachment of the foetal membranes. The chemotactic activity of cotyledons for mononuclear leukocytes was used as a parameter to see whether immune assisted detachment of the foetal membranes had occurred. Cotyledons were collected from spontaneously calving non-retained placenta cows and from dexamethasone induced non-retained placenta and retained placenta cows. The study showed that the chemotactic activity of cotyledons for mononuclear leukocytes was lower (P < 0.001) in cotyledons obtained from retained placenta cows in which parturition was induced with dexamethasone compared to the chemotactic activity of cotyledons obtained from spontaneously calving non-retained placenta cows, whereas the chemotactic activity of cotyledons obtained from induced non-retained placenta cows was not lower (P = 0.10) than the chemotactic activity of cotyledons obtained from spontaneously calving non-retained placenta cows. We concluded that induction of parturition with dexamethasone causes a failure of immune assisted detachment of the foetal membranes and the accompanying release of chemotactic factors. As a result, the chemotactic activity of cotyledons for mononuclear leukocytes is lower in induced retained placenta cows than in cotyledons from non-retained placenta cows in which successful immune assisted detachment of the foetal membranes occurs.
Assuntos
Doenças dos Bovinos/induzido quimicamente , Dexametasona/efeitos adversos , Trabalho de Parto Induzido/veterinária , Leucócitos Mononucleares/imunologia , Placenta Retida/veterinária , Placenta/imunologia , Animais , Bovinos , Doenças dos Bovinos/imunologia , Quimiotaxia/imunologia , Cotilédone , Membranas Extraembrionárias/imunologia , Membranas Extraembrionárias/fisiopatologia , Feminino , Glucocorticoides/efeitos adversos , Trabalho de Parto Induzido/métodos , Placenta Retida/induzido quimicamente , Placenta Retida/imunologia , GravidezRESUMO
Bovine embryos produced in vitro differ substantially from embryos produced in vivo in the mRNA expression patterns of genes important for development. Several factors in the in vitro production systems have profound effects on embryonic mRNA expression patterns. The effects of the type of maturation on the expression pattern of genes important for development in blastocysts produced in vitro have not yet been investigated. The aim of the present study was to investigate the effects of various maturational protocols on the relative abundance of a panel of six marker genes, indicative of compaction and cavitation, metabolism, stress susceptibility and RNA processing, in bovine blastocysts produced in vitro. Four groups of blastocysts were analysed by a sensitive semi-quantitative RT-PCR assay. Blastocysts were produced in vitro from oocytes of different origin from: (1) 3-8 mm follicles; (2) preovulatory follicles before the LH surge; and (3) preovulatory follicles 24 h after the LH surge. The first two groups were matured in vitro, whereas the third group had undergone maturation in vivo. A fourth group comprised blastocysts developed entirely in vivo. Expression of glucose transporter 1 was significantly (P < 0.05) higher, and expression of desmocollin 2 and plakophilin tended to be higher (P < 0.1) for in vivo (group 4) compared with in vitro blastocysts (group 1), whereas no differences were found for heat shock protein 70.1, E-cadherin and poly(A) polymerase. Expression of the six transcripts did not differ among blastocysts produced in vitro from oocytes of groups 1, 2 and 3. Results indicate that alterations in the relative abundance of these transcripts in blastocysts produced in vitro cannot primarily be attributed to the origin of the oocyte, but are likely to have been induced by post-maturation or fertilization culture conditions.