Bovine pre-implantation embryos are sensitive to high temperatures. The hyperthermia resulting from maternal heat stress leads to an increased loss of early stage embryos. The effects of hyperthermia appear to be more pronounced in the zygote than blastocyst stages. There is also evidence to suggest that B. indicus embryos show better resistance to heat shock as compared to B. taurus embryos. The mechanism of thermotolerance in B. indicus embryos is unknown and it is also unclear if the thermotolerance of these embryos is a result of maternal or paternal contributions. There is also evidence to suggest that male embryos survive heat shock better than female embryos. This research therefore aimed 1. To examine the effect of heat shock on day-7 bovine embryos 2. To study the influence of maternal and paternal genotype on the embryo's ability to survive up to 48 hours post heat shock treatment 3. To study the expression of HSP70 in heat-shocked and non-heat shocked embryos and compare B. indicus and B. taurus embryos. 4. To compare the effects of heat shock on rapidly developing (day-6 morulae) and slowly developing (day-7 morulae) embryos to heat shock treatments 5. To determine the effect of heat shock on the sex ratio of the surviving embryos The work described in this thesis used an in vitro protocol for heat shock studies on embryos, based on observed in vivo rectal temperature fluctuations in heat stressed cows. The first study examined the effects of heat shock on embryos at the morula or blastocyst stage on day 7 of in vitro culture. The embryos were produced in vitro from oocytes collected from ovaries of either pure breed B. indicus or B. taurus and fertilised by frozen semen straws of either B. indicus or B. taurus bulls. Day-7 morulae or blastocysts were used for the study. The embryos were subjected to heat shock (HS) (41.5&degC) or non-heat shock (NHS) (39&degC) temperatures. Embryo survival and development 48 hours (48 h) post treatment were recorded. The data were analysed using binary logistic regression using logit link function to determine the Odds ratio (OR) and 95% confidence limits for individual factors. The variables used as factors in the analysis were replicate, heat shock, maternal genotype (B. indicus vs B. taurus), paternal genotype (B. indicus vs B. taurus) and stage at which heat shock was applied (morula or blastocyst). The outcome variables used for analysis were the number of viable embryos from the total treated and the proportion reaching expanded or hatched blastocyst stage, and the proportion of male embryos. Heat shock significantly reduced the probability of embryo survival by more than half (OR = 0.47; P ≤ 0.001) and reduced the probability of the embryo's progression to the expanded or hatched blastocyst stage by almost half (OR = 0.58; P = 0.005) as compared to NHS embryos. The probability of survival of embryos with B. indicus paternal genotype (confounded by the use of a single sire) was double (OR = 2.00; P = 0.002) that of embryos with B. taurus paternal genotype. The heat shock x paternal B. indicus genotype interaction was found to be non-significant. Maternal B. indicus genotype showed no influence on thermotolerance. Nevertheless, the probability of progression to expanded blastocysts for embryos with maternal B. indicus genotypes was double (OR = 2.05; P = 0.030) that of embryos with maternal B. taurus genotype. Comparison of day-7 morulae with day-7 blastocysts showed that the probability of day-7 blastocysts surviving until 48 h after treatment was almost two and half times greater (OR = 2.39; P ≤ 0.001). The probability of survival of a blastocyst with paternal B. indicus genotype was almost twice (OR = 1.95; P = 0.041) when compared to a blastocyst with B. taurus paternal genotype. The interaction term of heat shock × blastocyst stage was found to be significant (OR = 2.70; P = 0.038) indicating that blastocyst stage embryos were resistant to heat shock. The study showed a trend towards survival of more male embryos (61% males vs 39% females) under heat shock conditions (OR = 1.64; P = 0.070) indicating that male embryos may be resistant to heat shock. The second study was designed to detect the induced form of HSP70 in heat shocked and non-heat shocked day-7 bovine embryos and to compare the patterns between B. indicus embryos and B. taurus embryos. Comparison of confocal images showed that staining for HSP70 was present in most embryos whether heat shocked or not and found to be concentrated in the nuclei and cytoplasm. Heat shock appears to have increased HSP70 staining intensity in both the nucleus and the cytoplasm, suggesting increased expression of HSP70 after heat shock. The same general staining patterns were seen in heat shocked and non-heat shocked embryos of B. indicus and B. taurus embryos. In the third experiment, embryos were examined for the effects of heat shock on day-7 or on day-6 of their in vitro culture. The data were analysed to study the effects of heat shock, stage at heat shock (day-7 blastocysts vs day-7 morulae) and day of heat shock (day-7 vs day-6) on embryo survival and progression to expanded or hatched blastocysts 48 h post treatment. We found that heat shock reduced the probability of survival by more than half (OR = 0.40; P = 0.004). Probability of survival of day-7 embryos (confounded by rapidly developing blastocysts and slow developing morulae) was less than half (OR = 0.36; P = 0.008), that of day-6 embryos. The data were then analysed to study the effects of heat shock on day-7 blastocysts and day-7 morulae for embryo survival post treatment. Heat shock negatively affected embryo survival (OR = 0.35; P = 0.007). The probability of day-7 blastocysts surviving HS and NHS was more than two and a half times greater (OR = 2.71; P = 0.008) than that of day-7 morulae. No interaction of heat shock and blastocyst stage was noticed. Subsequently the effects of heat shock and the effects of the day of heat shock on morula stage embryos were examined. Overall, heat shock reduced the probability of survival (OR = 0.35; P = 0.009) and the probability of embryo development to the expanded or hatched blastocysts (OR = 0.35; P ≤ 0.001), 48 h post treatment. The probability of day-6 morulae surviving HS and NHS was almost three times higher (OR = 2.81; P = 0.007) than that of day-7 morulae. The interaction of stage of development with heat shock was not significant. We concluded that an embryo that was capable of developing to the blastocyst stage by day-7 or morula stage by day-6 had better survival and higher probability of progressing to expanded or hatched stage when compared to an embryo that had slow development (day-7 morulae). The study showed a significantly different effect of heat shock on the survival of male and female embryos (63% males vs 36% females, OR = 1.79; P = 0.014). In our final study, embryos were produced from three different bulls each of B. indicus or B. taurus genotype. Heat shock effects consistently and negatively affected survival of embryos (OR = 0.29; P ≤ 0.001) and their ability to progress to the expanded or hatched blastocysts (OR = 0.42; P ≤ 0.001). Embryos with paternal B. indicus genotype showed no advantage of survival over embryos with paternal B. taurus genotype embryos. When the day-7 blastocysts were compared with the day-7 morulae, the probability of day-7 blastocysts surviving HS or NHS was more than double (OR = 2.23; P = 0.009) that of day-7 morulae. In this study the effect of survival of the interaction term of heat shock treatment with the blastocyst stage was significant and negative (OR = 0.49; P = 0.040). However the interaction term of blastocyst stage x HS for an embryo’s ability to progress to expanded or hatched blastocyst stage was positive (OR = 2.00; P = 0.052), indicating that the embryos that did survive heat shock were capable of continuing their developmental progress. Although more male embryos (55% male vs 45% female) survived heat shock, the effect for this study was non-significant. In summary, the studies described in this thesis successfully tested a new in vitro heat shock protocol based on in vivo temperature changes experienced by heat stressed cows. Heat shock was consistent in negatively affecting embryo survival. Heat shock also negatively affected the embryo's progression to the expanded or hatched blastocyst stage by 48 h post treatment. We observed variable cytoplasmic and nuclear staining for HSP70 in day-7 blastocysts of both B. indicus and B. taurus. This distribution did not change dramatically after heat shock, but staining appeared to be more intense in heat shocked embryos, suggesting that there was increased expression of HSP70 after heat shock. No difference in this pattern was observed between B. indicus and B. taurus embryos. The speed of development of an embryo until being subjected to either heat shock or non heat shock temperatures affected the probability of survival and further development. However, the interaction term of day-7 blastocyst stage and heat shock was inconsistent, meaning that the rate of development appeared to specifically protect against heat shock in some studies while in the other studies, the apparent protective effect extended to control as well as heat shocked embryos. Our study found no significant influence of B. indicus paternal genotype on embryo survival. Our study showed evidence of B. indicus maternal genotype influence on the embryo's ability to progress to expanded blastocysts but not on embryo survival. The study found a clear trend towards an increased proportion of male embryos surviving heat shock conditions. In some studies this was significant, and in others it was not, but the trend was always in the same direction. This suggests that male embryos are more resistant to the effects of heat shock in vitro.

Bovine pre-implantation embryos are sensitive to high temperatures. The hyperthermia resulting from maternal heat stress leads to an increased loss of early stage embryos. The effects of hyperthermia appear to be more pronounced in the zygote than blastocyst stages. There is also evidence to suggest that B. indicus embryos show better resistance to heat shock as compared to B. taurus embryos. The mechanism of thermotolerance in B. indicus embryos is unknown and it is also unclear if the thermotolerance of these embryos is a result of maternal or paternal contributions. There is also evidence to suggest that male embryos survive heat shock better than female embryos. This research therefore aimed 1. To examine the effect of heat shock on day-7 bovine embryos 2. To study the influence of maternal and paternal genotype on the embryo's ability to survive up to 48 hours post heat shock treatment 3. To study the expression of HSP70 in heat-shocked and non-heat shocked embryos and compare B. indicus and B. taurus embryos. 4. To compare the effects of heat shock on rapidly developing (day-6 morulae) and slowly developing (day-7 morulae) embryos to heat shock treatments 5. To determine the effect of heat shock on the sex ratio of the surviving embryos The work described in this thesis used an in vitro protocol for heat shock studies on embryos, based on observed in vivo rectal temperature fluctuations in heat stressed cows. The first study examined the effects of heat shock on embryos at the morula or blastocyst stage on day 7 of in vitro culture. The embryos were produced in vitro from oocytes collected from ovaries of either pure breed B. indicus or B. taurus and fertilised by frozen semen straws of either B. indicus or B. taurus bulls. Day-7 morulae or blastocysts were used for the study. The embryos were subjected to heat shock (HS) (41.5&degC) or non-heat shock (NHS) (39&degC) temperatures. Embryo survival and development 48 hours (48 h) post treatment were recorded. The data were analysed using binary logistic regression using logit link function to determine the Odds ratio (OR) and 95% confidence limits for individual factors. The variables used as factors in the analysis were replicate, heat shock, maternal genotype (B. indicus vs B. taurus), paternal genotype (B. indicus vs B. taurus) and stage at which heat shock was applied (morula or blastocyst). The outcome variables used for analysis were the number of viable embryos from the total treated and the proportion reaching expanded or hatched blastocyst stage, and the proportion of male embryos. Heat shock significantly reduced the probability of embryo survival by more than half (OR = 0.47; P ≤ 0.001) and reduced the probability of the embryo's progression to the expanded or hatched blastocyst stage by almost half (OR = 0.58; P = 0.005) as compared to NHS embryos. The probability of survival of embryos with B. indicus paternal genotype (confounded by the use of a single sire) was double (OR = 2.00; P = 0.002) that of embryos with B. taurus paternal genotype. The heat shock x paternal B. indicus genotype interaction was found to be non-significant. Maternal B. indicus genotype showed no influence on thermotolerance. Nevertheless, the probability of progression to expanded blastocysts for embryos with maternal B. indicus genotypes was double (OR = 2.05; P = 0.030) that of embryos with maternal B. taurus genotype. Comparison of day-7 morulae with day-7 blastocysts showed that the probability of day-7 blastocysts surviving until 48 h after treatment was almost two and half times greater (OR = 2.39; P ≤ 0.001). The probability of survival of a blastocyst with paternal B. indicus genotype was almost twice (OR = 1.95; P = 0.041) when compared to a blastocyst with B. taurus paternal genotype. The interaction term of heat shock × blastocyst stage was found to be significant (OR = 2.70; P = 0.038) indicating that blastocyst stage embryos were resistant to heat shock. The study showed a trend towards survival of more male embryos (61% males vs 39% females) under heat shock conditions (OR = 1.64; P = 0.070) indicating that male embryos may be resistant to heat shock. The second study was designed to detect the induced form of HSP70 in heat shocked and non-heat shocked day-7 bovine embryos and to compare the patterns between B. indicus embryos and B. taurus embryos. Comparison of confocal images showed that staining for HSP70 was present in most embryos whether heat shocked or not and found to be concentrated in the nuclei and cytoplasm. Heat shock appears to have increased HSP70 staining intensity in both the nucleus and the cytoplasm, suggesting increased expression of HSP70 after heat shock. The same general staining patterns were seen in heat shocked and non-heat shocked embryos of B. indicus and B. taurus embryos. In the third experiment, embryos were examined for the effects of heat shock on day-7 or on day-6 of their in vitro culture. The data were analysed to study the effects of heat shock, stage at heat shock (day-7 blastocysts vs day-7 morulae) and day of heat shock (day-7 vs day-6) on embryo survival and progression to expanded or hatched blastocysts 48 h post treatment. We found that heat shock reduced the probability of survival by more than half (OR = 0.40; P = 0.004). Probability of survival of day-7 embryos (confounded by rapidly developing blastocysts and slow developing morulae) was less than half (OR = 0.36; P = 0.008), that of day-6 embryos. The data were then analysed to study the effects of heat shock on day-7 blastocysts and day-7 morulae for embryo survival post treatment. Heat shock negatively affected embryo survival (OR = 0.35; P = 0.007). The probability of day-7 blastocysts surviving HS and NHS was more than two and a half times greater (OR = 2.71; P = 0.008) than that of day-7 morulae. No interaction of heat shock and blastocyst stage was noticed. Subsequently the effects of heat shock and the effects of the day of heat shock on morula stage embryos were examined. Overall, heat shock reduced the probability of survival (OR = 0.35; P = 0.009) and the probability of embryo development to the expanded or hatched blastocysts (OR = 0.35; P ≤ 0.001), 48 h post treatment. The probability of day-6 morulae surviving HS and NHS was almost three times higher (OR = 2.81; P = 0.007) than that of day-7 morulae. The interaction of stage of development with heat shock was not significant. We concluded that an embryo that was capable of developing to the blastocyst stage by day-7 or morula stage by day-6 had better survival and higher probability of progressing to expanded or hatched stage when compared to an embryo that had slow development (day-7 morulae). The study showed a significantly different effect of heat shock on the survival of male and female embryos (63% males vs 36% females, OR = 1.79; P = 0.014). In our final study, embryos were produced from three different bulls each of B. indicus or B. taurus genotype. Heat shock effects consistently and negatively affected survival of embryos (OR = 0.29; P ≤ 0.001) and their ability to progress to the expanded or hatched blastocysts (OR = 0.42; P ≤ 0.001). Embryos with paternal B. indicus genotype showed no advantage of survival over embryos with paternal B. taurus genotype embryos. When the day-7 blastocysts were compared with the day-7 morulae, the probability of day-7 blastocysts surviving HS or NHS was more than double (OR = 2.23; P = 0.009) that of day-7 morulae. In this study the effect of survival of the interaction term of heat shock treatment with the blastocyst stage was significant and negative (OR = 0.49; P = 0.040). However the interaction term of blastocyst stage x HS for an embryo’s ability to progress to expanded or hatched blastocyst stage was positive (OR = 2.00; P = 0.052), indicating that the embryos that did survive heat shock were capable of continuing their developmental progress. Although more male embryos (55% male vs 45% female) survived heat shock, the effect for this study was non-significant. In summary, the studies described in this thesis successfully tested a new in vitro heat shock protocol based on in vivo temperature changes experienced by heat stressed cows. Heat shock was consistent in negatively affecting embryo survival. Heat shock also negatively affected the embryo's progression to the expanded or hatched blastocyst stage by 48 h post treatment. We observed variable cytoplasmic and nuclear staining for HSP70 in day-7 blastocysts of both B. indicus and B. taurus. This distribution did not change dramatically after heat shock, but staining appeared to be more intense in heat shocked embryos, suggesting that there was increased expression of HSP70 after heat shock. No difference in this pattern was observed between B. indicus and B. taurus embryos. The speed of development of an embryo until being subjected to either heat shock or non heat shock temperatures affected the probability of survival and further development. However, the interaction term of day-7 blastocyst stage and heat shock was inconsistent, meaning that the rate of development appeared to specifically protect against heat shock in some studies while in the other studies, the apparent protective effect extended to control as well as heat shocked embryos. Our study found no significant influence of B. indicus paternal genotype on embryo survival. Our study showed evidence of B. indicus maternal genotype influence on the embryo's ability to progress to expanded blastocysts but not on embryo survival. The study found a clear trend towards an increased proportion of male embryos surviving heat shock conditions. In some studies this was significant, and in others it was not, but the trend was always in the same direction. This suggests that male embryos are more resistant to the effects of heat shock in vitro.

A large proportion of the beef industry in northern Australia is composed of tropically adapted cattle, due to their propensity for tick and drought resistance. It has been suggested that a large conical cervix is responsible for decreased fertility in these cattle where a conical cervix is defined as having a caudal to cranial cervical diameter difference of greater than 15 mm. Studies were conducted in order to ascertain the incidence of conical cervix and the heritability of cervical diameter in tropically adapted beef cattle in Queensland. An initial study was conducted on 246 Santa Gertrudis females from four properties. Caudal and cranial cervical measurements were taken with transrectal B-mode ultrasound using the Aloka SSD_500 scanner and a 5 MHz linear probe. Analysis of data was by AS REML, including the effects of sire, parity and property. Sire was included as a random effect, whereas parity and property were included in the analysis as fixed effects. Sire effects were significant. A sire model was used to calculate a heritability estimate of 0.60 ± 0.27 for uterine cervical diameter. An analysis of variance showed that parity had a significant effect on cervical diameter, with cervical diameter increasing as parity level increased. Property had no effect on cervical diameter A more detailed study was conducted on 850 cattle from five properties. Breeds represented were Santa Gertrudis, Brahman, Brahman Cross, Belmont Red and Belmond Red Cross. Caudal and cranial cervical diameter, sire, parity and breed were recorded for each animal. Once again, sire effects were significant resulting in a heritability estimate of 0.46 ± 0.15. An analysis of variance showed parity effects to be significant (α=0.05) while property and breed effects did not influence cervical diameter. However property and breed were heavily confounded due to the practice of many stud breeders of running one breed per property. Breed and parity were also heavily confounded as Santa Gertrudis breed cattle were the only cattle available that had already produced one or more calves. In order to examine the relationship between cervical diameter and liveweight, a subset of 568 cows from the above group also had their weight in kilograms recorded. Animals were chosen for this study based on the availability of scales at each property. A Pearson correlation test resulted in a correlation coefficient of 0.043 between uterine cervical diameter and animal liveweight. This demonstrates that there is a negligible linear relationship between cervical diameter and liveweight. The relationship between cervix diameter and calving outcome was not investigated in this study. Although calving records were obtained for a number of animals in this study, many variables affecting calving outcome could not be accounted for such as disease outbreaks, artificial insemination technique and other management factors. Previous studies have suggested a relationship between cervical diameter and infertility but the present study was unable to draw conclusions regarding this. Although this study has shown that uterine cervical diameter is a moderately to highly heritable trait, it is not recommended that producers cull animals based on their uterine cervical dimensions at this stage, as the relationship between uterine cervical diameter and fertility is still poorly understood.

A influência da oferta do alimento no ciclo de vida e considerando a estrobilização de Nausithoe aurea Silveira & Morandini, 1997 foi estudada. A espécie foi representada por indivíduos de 5 localidades brasileiras, abrangendo quase toda a distribuição conhecida da espécie. Apoiados por protocolo de jejum-alimentação, com duração de 105 dias, estabelecido a partir de um projeto piloto, os cifístomas foram observados quanto à indução da estrobilização ou então sua ausência diante de jejum muito prolongado. Os cifistomas foram divididos em 4 gripos, de 30 indivíduos cada, sendo estes acompanhados em 2 fases (\"ômega\" e \"psi\"). Os cifistomas apresentaram uma indução de estrobilização muito representativa nos períodos de alimentação. A quantidade de alimento não foi o fator mais importante na indução do início da estrobilização, mas a disponibilidade de alimento, em comparação com a sua ausência foi um forte indutor. Assim, um teste de outro fator indutor da estrobilização foi realizado, bem como algumas características que acompanham todo o fenômeno de estrobilização nesta espécie. / The influence of food availability in the life cycle and considering strobilation of Nausithoe aurea Silveira & Morandini, 1997 was studied. The species was represented by polyps from 5 Brazilian localities, covering most of the known distribution area of the species. Based in a protocol of hunger-feeding, lasting over 105 days, established following a pilot project, the scyphistomae were observed in regard to the induction of strobilation or its absence due to prolonged starvation. The scyphistomae were divided in 4 groups, of 30 individuals each, and these groups followed in two phases ( and ). The scyphistomae showed intense strobilation during the feeding periods. The amount of food was not the most important factor leading to strobilation, but the availability of food, compared with its absence was a strong inducing factor. Therefore, a test for another inducing factor was accomplished, as well as for some features present during the complete strobilation phenomena for this species.

No description available.

A very high proportion of beef cows in Australia are mated to bulls at pasture. A multiplicity of systems for pasture mating are presently in use. Bulls are mated singly or in groups, they are set-stocked during the mating period or rotated about the different groups of cows, they are mated at the rate of 2, 3, 4, 5 or 6 bulls per 100 cows, young bulls are mated to cows in company with old bulls or other young bulls (Dickson 1966). There is little scientific basis for any of these mating systems since basic information on the sexual and social behaviour of beef bulls at pasture is lacking. Such data are needed so that optimum use can be made of beef bulls in pasture mating. (For complete abstract open document)

Orientador: Francisco Guilherme Leite / Banca: Paulo Henrique Franceschini / Banca: Rubens Paes Arruda / Resumo: A utilização da L-carnitina - ácido y-trimethilamino- ß-hidróxido butírico - visando melhorar os parâmetros espermáticos tem sido intensivamente utilizado em medicina humana e em menor escala em medicina veterinária com resultados satisfatórios. O objetivo deste estudo foi verificar a influência da suplementação oral de L-carnitina em sêmen criopreservado de garanhões. Utilizou-se neste experimento quatro garanhões submetidos a duas colheitas de sêmen por semana por um período de quatro semanas durante o mês de agosto de 2001; amostras se sêmen desses animais, agora denominado TO, foram criopreservadas. Os mesmos quatro garanhões receberam uma suplementação oral de quinze gramas de L-carnitina uma vez ao dia nos meses de maio, junho, julho e agosto de 2002 e no mês de agosto de 2002 foram submetidos a duas colheitas de sêmen semanais, tendo suas amostras também criopreservadas, que passaram a ser denominado tratado (T1). Foram analisados e comparados entre si os seguintes parâmetros espermáticos:- total de espermatozóides no ejaculado e integridade da membrana espermática e através de análise computadorizada as variáveis motilidade total (MT), motilidade progressiva (MP), linearidade (LIN), velocidade de trajeto (VAP), velocidade progressiva (VSL) e velocidade curvilinear (VCL) antes e após da realização de um teste de termo-resistência (TTR). Foi realizado um delineamento casualizado com oito repetições (dois tratamentos e quatro garanhões); empregou-se análise de variância - ANOVA - com posterior desdobramento para estudar o efeito dos tratamentos em cada um dos garanhões - Teste de Tukey - o nível de significância adotado foi p<0,05... (resumo completo, clicar acesso no endereço eletrônico abaixo) / Abstract: Owing its positive effect on the improvement of spermatic parameters, L- carnitine - ?-trimethilamino- ß-hidroxid butiric acid - has been intensively utilized in human medicine and in a lower scale in veterinary medicine with satisfactory results. The objective of this study was to verify the influence of oral supplementation with L-carnitine on cryopreserved stallion semen. Four stallions were submitted to semen collection twice a week during a four week period in August of 2001. The collected samples from those horses were then cryopreserved and they were assigned as a control group (T0). The same horses received fifteen grams of L- carnitine by oral supplementation, once a day, during May, June, July and August of 2002, and then they were submitted to semen collection twice a week in August of 2002. Those collected samples were also equally cryopreserved, and assigned as treatment group (T1). The following spermatic parameters were analyzed and submitted to a pair wise comparison: total sperm number in the ejaculate and sperm membrane integrity and by computer analyze, variables as: total motility (TM), progressive motility (PM), linearity (LIN), path velocity (VAP), progressive velocity (VSL), and track speed (VCL). Those variables were then determined before and after a term resistance test (TRT). A casual design was established using eight repetitions (two treatments and four stallions). To investigate the treatment effect, analysis of variance (ANOVA) was performed and to investigate de effect within stallion, the Tukey's test - significance level was established as p£ 0.05. The means and standard errors of means for the variable total motility, determined before and after the term resistance test, total sperm number in the ejaculate and sperm membrane integrity was significantly higher in the treatment group (T1) when compared to the control group (T0)... (complete abstract, access undermentioned eletronic address) / Mestre

Made available in DSpace on 2014-06-11T19:29:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-02-14Bitstream added on 2014-06-13T19:17:42Z : No. of bitstreams: 1 lima_mm_me_jabo.pdf: 215055 bytes, checksum: 1a2d1414c1ce8862b1dc8a0b31b6a6b5 (MD5) / A utilização da L-carnitina - ácido y-trimethilamino- ß-hidróxido butírico - visando melhorar os parâmetros espermáticos tem sido intensivamente utilizado em medicina humana e em menor escala em medicina veterinária com resultados satisfatórios. O objetivo deste estudo foi verificar a influência da suplementação oral de L-carnitina em sêmen criopreservado de garanhões. Utilizou-se neste experimento quatro garanhões submetidos a duas colheitas de sêmen por semana por um período de quatro semanas durante o mês de agosto de 2001; amostras se sêmen desses animais, agora denominado TO, foram criopreservadas. Os mesmos quatro garanhões receberam uma suplementação oral de quinze gramas de L-carnitina uma vez ao dia nos meses de maio, junho, julho e agosto de 2002 e no mês de agosto de 2002 foram submetidos a duas colheitas de sêmen semanais, tendo suas amostras também criopreservadas, que passaram a ser denominado tratado (T1). Foram analisados e comparados entre si os seguintes parâmetros espermáticos:- total de espermatozóides no ejaculado e integridade da membrana espermática e através de análise computadorizada as variáveis motilidade total (MT), motilidade progressiva (MP), linearidade (LIN), velocidade de trajeto (VAP), velocidade progressiva (VSL) e velocidade curvilinear (VCL) antes e após da realização de um teste de termo-resistência (TTR). Foi realizado um delineamento casualizado com oito repetições (dois tratamentos e quatro garanhões); empregou-se análise de variância - ANOVA - com posterior desdobramento para estudar o efeito dos tratamentos em cada um dos garanhões - Teste de Tukey - o nível de significância adotado foi p<0,05... / Owing its positive effect on the improvement of spermatic parameters, L- carnitine - ?-trimethilamino- ß-hidroxid butiric acid - has been intensively utilized in human medicine and in a lower scale in veterinary medicine with satisfactory results. The objective of this study was to verify the influence of oral supplementation with L-carnitine on cryopreserved stallion semen. Four stallions were submitted to semen collection twice a week during a four week period in August of 2001. The collected samples from those horses were then cryopreserved and they were assigned as a control group (T0). The same horses received fifteen grams of L- carnitine by oral supplementation, once a day, during May, June, July and August of 2002, and then they were submitted to semen collection twice a week in August of 2002. Those collected samples were also equally cryopreserved, and assigned as treatment group (T1). The following spermatic parameters were analyzed and submitted to a pair wise comparison: total sperm number in the ejaculate and sperm membrane integrity and by computer analyze, variables as: total motility (TM), progressive motility (PM), linearity (LIN), path velocity (VAP), progressive velocity (VSL), and track speed (VCL). Those variables were then determined before and after a term resistance test (TRT). A casual design was established using eight repetitions (two treatments and four stallions). To investigate the treatment effect, analysis of variance (ANOVA) was performed and to investigate de effect within stallion, the Tukey's test - significance level was established as p£ 0.05. The means and standard errors of means for the variable total motility, determined before and after the term resistance test, total sperm number in the ejaculate and sperm membrane integrity was significantly higher in the treatment group (T1) when compared to the control group (T0)... (complete abstract, access undermentioned eletronic address)

Made available in DSpace on 2014-06-11T19:29:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-12-17Bitstream added on 2014-06-13T20:38:43Z : No. of bitstreams: 1 silva_jcc_me_jabo.pdf: 166737 bytes, checksum: 76b0116551aaba2c16119c8f6c46924d (MD5) / Fatores como idade, dose e tipo de hormônio utilizado na superovulação, início do tratamento de superovulação, uso de progestágeno, estação do ano, propriedade e superovulação repetida foram relacionados com a produção de embriões de vacas Nelore. Os dados analisados envolveram 884 tentativas de superovulação em 318 doadoras com idade entre dois e 21 anos, manejadas em seis propriedades localizadas no Estado de Mato Grosso do Sul. Os dados foram analisados utilizando o GLM do SAS. Dos fatores analisados, somente a idade das doadoras e a propriedade afetaram a produção e a qualidade dos embriões. Vacas senis (>14 anos) produziram, em média, 5,0 l 0,2 e 3,0 l 0,1 embriões (total e viáveis, respectivamente) a menos que vacas jovens (p<0,001), enquanto que um manejo diferenciado aumentou em aproximadamente 2,0 l 0,4 o número de embriões viáveis. O tipo de hormônio (Plusetä, Super-Ovä, Ovagenä, FSH-Pä) ou dosagem (50, 75 ou 100%) utilizada na superovulação não influenciou a produção de embriões (p>0,05). Não houve diferença da resposta quando o tratamento de superovulação foi iniciado entre os dias 8 a 12 do ciclo (p>0,05). A superovulação associada a um implante com progestágenos, iniciado a qualquer momento do ciclo, foi tão eficiente (p>0,05) quanto o tratamento convencional iniciado no meio do ciclo. Finalmente, constatou-se que a superovulação repetida por 6 ou mais vez não afetou a produção ou qualidade dos embriões. Concluiu-se que o manejo e, a idade da doadora são fatores que devem ser considerados ao implementar um programa de transferência de embriões na raça Nelore, por limitar a produção de embriões nessa sub-espécie. / Factors such as age, dose and kind of superovulatory hormone, starting point of the superovulatory treatment, use of progestagens, season, property and repetition of superovulatory treatments were related to embryo production in Nelore cows. Analysed data comprised 884 superovulation attempts on 318 donor cows, with their ages ranging between two and 21 years, managed by six different property owners, in Mato Grosso do Sul State, Brazil. Data were analysed using the General Linear Model of SAS. Among all the studied factors, only the age of donor cows and the property affected embryo production and quality. Older cows (>14 years old) produced a mean of five and three embryos (total and viable, respectively) less than younger ones (p < 0,001), and a better management (property) was responsible for a mean of two more viable embryos. The kind of superovulatory hormone (PlusetTM, Super-OvTM, OvagenTM, FSH-PTM) and its dose (50, 75 or 100%), did not affect embryo production (p > 0,05). Superovulatory response wasnþt different when treatments started on day 8, 9, 10, 11 or 12 of the cycle (p > 0,05), nor when it began with a progestagen implant at any moment of the cycle, as compared to conventional treatments, beginning at the middle of the cycle (p > 0,05). Finally, it was stated that repetition of six or more superovulatory treatments, didn't affect embryo production or quality. It is concluded that management, and specially age of the donors are factors to be taken into account when an embryo transfer program is to be performed in Nelore females, because they affect superovulatory performance in this breed of cows.

Orientador: Rafael Herrera Alvarez / Banca: Cesar Roberto Esper / Banca: Pietro Sampaio Baruselli / Resumo: Fatores como idade, dose e tipo de hormônio utilizado na superovulação, início do tratamento de superovulação, uso de progestágeno, estação do ano, propriedade e superovulação repetida foram relacionados com a produção de embriões de vacas Nelore. Os dados analisados envolveram 884 tentativas de superovulação em 318 doadoras com idade entre dois e 21 anos, manejadas em seis propriedades localizadas no Estado de Mato Grosso do Sul. Os dados foram analisados utilizando o GLM do SAS. Dos fatores analisados, somente a idade das doadoras e a propriedade afetaram a produção e a qualidade dos embriões. Vacas senis (>14 anos) produziram, em média, 5,0 l 0,2 e 3,0 l 0,1 embriões (total e viáveis, respectivamente) a menos que vacas jovens (p<0,001), enquanto que um manejo diferenciado aumentou em aproximadamente 2,0 l 0,4 o número de embriões viáveis. O tipo de hormônio (Plusetä, Super-Ovä, Ovagenä, FSH-Pä) ou dosagem (50, 75 ou 100%) utilizada na superovulação não influenciou a produção de embriões (p>0,05). Não houve diferença da resposta quando o tratamento de superovulação foi iniciado entre os dias 8 a 12 do ciclo (p>0,05). A superovulação associada a um implante com progestágenos, iniciado a qualquer momento do ciclo, foi tão eficiente (p>0,05) quanto o tratamento convencional iniciado no meio do ciclo. Finalmente, constatou-se que a superovulação repetida por 6 ou mais vez não afetou a produção ou qualidade dos embriões. Concluiu-se que o manejo e, a idade da doadora são fatores que devem ser considerados ao implementar um programa de transferência de embriões na raça Nelore, por limitar a produção de embriões nessa sub-espécie. / Abstract: Factors such as age, dose and kind of superovulatory hormone, starting point of the superovulatory treatment, use of progestagens, season, property and repetition of superovulatory treatments were related to embryo production in Nelore cows. Analysed data comprised 884 superovulation attempts on 318 donor cows, with their ages ranging between two and 21 years, managed by six different property owners, in Mato Grosso do Sul State, Brazil. Data were analysed using the General Linear Model of SAS. Among all the studied factors, only the age of donor cows and the property affected embryo production and quality. Older cows (>14 years old) produced a mean of five and three embryos (total and viable, respectively) less than younger ones (p < 0,001), and a better management (property) was responsible for a mean of two more viable embryos. The kind of superovulatory hormone (PlusetTM, Super-OvTM, OvagenTM, FSH-PTM) and its dose (50, 75 or 100%), did not affect embryo production (p > 0,05). Superovulatory response wasnþt different when treatments started on day 8, 9, 10, 11 or 12 of the cycle (p > 0,05), nor when it began with a progestagen implant at any moment of the cycle, as compared to conventional treatments, beginning at the middle of the cycle (p > 0,05). Finally, it was stated that repetition of six or more superovulatory treatments, didn't affect embryo production or quality. It is concluded that management, and specially age of the donors are factors to be taken into account when an embryo transfer program is to be performed in Nelore females, because they affect superovulatory performance in this breed of cows. / Mestre