Orientador: Guilherme de Paula Nogueira / Banca: Ed Hoffmann Madureira / Banca: Ciro Moraes Barros / Resumo: Avaliou-se a secreção de LHe FSH de plasmático em novilhasdurantea exposição à diferentes concentrações de progesterona(P4) e após a administração deGnRH ou benzoatodeestradiol (BE). Novenovilhas Nelore, pré-sincronizadas com PgF2a, emintervalo de 12 dias, foram submetidas a 6protocolos comrepetições casualizadas. Os 3 grupos de P4foram: CL (Corpo Lúteo), IMPL+CL (DIB® ecorpo lúteo) e IMPL(DIB®), eapós a remoçãodaP4 estimuladascom GnRH ou BE. Durante a P4, foicoletado sangue a cada12h e nos dias 3, 4 e 5 acada 15 min durante 6 h em 1 animalde cada grupo, depois da retiradados implantes e/ou aplicação de PgF2a, coletas foramrealizadas a cada 3hpor 24 h (BE) ou a cadahora por10h (GnRH) para quantificação de LH e FSH. O exame ultrasonográfico foi realizado a cada 12 he após o términodascoletas de sangue às 24h e 48h. Às 12 h após colocação do implante, o grupo IMPL+CLapresentou menorconcentração de LHque o grupo IMPL,após 36 h os grupos IMPL+C e IMPL apresentaram menorconcentração de LH que o grupo CL e às 60 h o grupo IMPL apresentou menor secreção que o grupo CL. Após 24 h da colocação dos implantes, o grupo IMPL apresentou maior secreção de FSH que os demais grupos, e após 48 e 60 h o grupo IMPL+CL apresentou maior secreção de FSH que o grupo CL. No grupo IMPL, a amplitude máxima do pico de LH foi maior após o GnRH quando comparado com o BE. No grupo CL as novilhas apresentaram menor número de folículos ovarianos e maior diâmetro do maior folículo em relação aos grupos IMPL+CL e IMPL. Quando foi aplicado BE, o grupo IMPL+CL apresentou menor taxa de ovulação com 24 h que os grupos CL e IMPL. Os protocolos de sincronização da ovulação empregados foram ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The LH and FSH secretion and follicle profile was evaluated during expositionto different progesterone (P4) concentration and afterGnRH or estradiol benzoate (BE) administration inNelore heifers. Nine heifers were pré-sinchronized with PGF2a (two injection with 12 days interval) received 6 treatments randomly repeated . There were 3 P4 groups: CL (corpus luteum), IMPL+CL (DIB®and CL) and IMPL (DIB®)that were stimulatedwith GnRH or BE after P4 removal. During P4 blood samples were collected every12 hand on days 3, 4and 5 every 15 minfor 6 hfrom 1 animal per group, after P4 device removal, every 3 hfor 24 h (BE)orevery hour for 10 h(GnRH), for LH and FSH quantification. Ultrasound examination was realizedevery 12 h until the end of blood samples, andthereafter 24 and 48 h. At 12hafter implant insertion the IMPL+CLgroup presented lower LH concentration than IMPL group, after 36 hthe animals with implant presented lower LH concentration than CL group, and after 60h the IMPL group had lower LH secretionthan CL one. On IMPL group,themaximum LH peak amplitude was higher in animalsthat received GnRH comparedto BE. Group with CL presented fewer follicles and higher largest follicle diameterthan IMPL+CLand IMPL. When BE was injected the IMPL+CL group presented lower ovulation rateat 24 h than CL and IMPLgroups. The ovulation synchronization protocols used wereefficient in promoting a preovulatory LH peak in Neloreheifers, independentlyof an associated CL or not to progesterone device. The GnRH treatment induced a higher LH peak amplitude and with an higer efficiency in stimulating ovulation in 24h than BE treatment, in animals with higher progesterone...(Complete abstract, click electronic access below) / Mestre

A inseminação artificial (IA) é uma técnica cada vez mais utilizada na suinocultura moderna, pois propicia ao suinocultor vantagens quanto ao desempenho dos reprodutores, ao controle dos cruzamentos e à facilidade na introdução de material genético. Entretanto, a produção de doses inseminantes com qualidade é um dos principais fatores envolvidos no sucesso da técnica. Nesse contexto, a adequada mensuração da concentração espermática do ejaculado suíno é parte fundamental da rotina de trabalho de Centrais de Inseminação Artificial em Suínos. Foram realizados dois experimentos onde se objetivou: Experimento 1 - avaliar a acurácia, a precisão e a robustez do volume do ejaculado do Espermiodensímetro de Karras (ESPM) e do Espectrofotômetro (ESPT), em comparação à Câmara de Neubauer (CN), técnica padrão e também produzir uma tabela de correção de escala do ESPM; Experimento 2 - avaliar o tempo gasto e a repetibilidade de cada técnica, além de comparar a tabela ajustada do ESPM produzida no Experimento 1 com a tabela padrão do ESPM. Utilizaram-se 141 ejaculados, que revelaram concentrações espermáticas médias (milhões de sptz/mL) e número médio de doses que poderiam ser produzidas, respectivamente de 229,1 e 22,6; 185,0 e 18,5; 283,6 e 28,0 para a CN, o ESPT e o ESPM. O viés médio (acurácia) obtido através da média da diferença do resultado da técnica alternativa e da técnica padrão, e o desvio-padrão do viés médio (precisão) do ESPT, em comparação à CN, foram, respectivamente de - 44,1 e 52,6, enquanto que para o ESPM foram de 54,5 e 44,8 (milhões de sptz/mL). Observou-se que o ESPT tende a subestimar e o ESPM a superestimar a concentração espermática, em comparação à CN. O ESPT foi igualmente preciso e mais acurado que o ESPM. Houve pouca influência do volume do ejaculado sobre os resultados do ESPM e do ESPT através dos resultados de robustez para o volume do ejaculado. O ESPM apresentou maior repetibilidade e menor tempo gasto para a realização dos exames, seguido do ESPT e, por último, da CN (P<0,05). A tabela produzida com os dados do Experimento 1 apresentou resultados mais aproximados aos da CN, em comparação com a tabela padrão do ESPM (2,96 bilhões de espermatozóides vivos/dose vs 2,36 bilhões de espermatozóides vivos/dose, respectivamente). Maiores informações de outras Centrais de Inseminação Artificial em Suínos (CIAS) sobre o uso a campo da tabela ajustada produzida, denominada \"Tabela Ajustada para o Espermiodensímetro LPS-FMVZ-USP\", seriam úteis para comprovar a sua eficiência a campo. / Artificial Insemination (AI) in swine is a rising technique that has been used during the last years at the swine production systems, because it furnish several advantages to the producers just like boar high efficiency, better breeding control and easiness in introducing foreign genetic materials. Nevertheless, high quality insemination doses output is one of the most important factors involving the technique success. In this manner, a correct measurement of the spermatic concentration of boars is a basic work routine of the Swine Artificial Insemination Centers (CIAS). Two trials had been performed, whose objectives were: Experiment 1 - evaluate the accuracy, precision and robustness for ejaculation volume of Spermdensimeter (ESPM) and Spectrofotometer (ESPT) in relation to the Neubauer Count chamber (CN), designed as the standard technique. Moreover, produce a scale correction of the ESPM table; Experiment 2 - evaluate the spent time and repetitiousness of each technique, and compare the ESPM adjusted table produced in Experiment 1 with the ESPM standard table. A total of 141 boar ejaculation was used for spermatic concentration measurement by the techniques described above. The average spermatic concentrations (106 sptz/mL) and average doses number were, respectively: 229.1 and 22.6, 185.0 and 18.5, 283.6 and 28.0 for CN, ESPT and ESPM. ESPT mean bias (accuracy) and standard deviation bias (precision), in relation to the CN were, respectively -44.1 and 52.6, while ESPM were 54.4 and 44.8 (106 sptz/mL). Through these results its possible to conclude that ESPT has a tendency to subestimate and ESPM to superestimate the spermatic concentration in relation to the CN. ESPT was more accurate and equally precise than ESPM. Little effect of ejaculation volume on accuracy and precision in both techniques (ESPM and ESPT) was confirmed by the robustness results. ESPM presented a minor coefficient of variation and timeless, followed by ESPT, and finally by CN (P<0,05). The adjusted table produced with Experiment 1 data presented similar results to CN, in relation to the ESPM standard table (2.96 billion of lives sptz/dose vs 2.36 billion of lives sptz/dose, respectively). Complementary data from others CIAS about field use of the ESPM adjusted table produced, named \"Adjusted Table for Karras Spermdensimeter LPS-FMVZ-USP\", would be useful to prove it efficiency.

Assisted reproduction (AR) became available in Mexico during the mid eighties. Since then, the AR industry has developed and flourished within a context of little regulation, considerable media coverage and an increasing number of consumers. As part of this process, terms such as 'assisted reproduction', 'infertility, ‘eligible AR users' and ‘qualified AR service provider' have required definitions. Through four years of multisited ethnographic work at clinics, conferences and online forums, and by analysing media coverage and legal debates around infertility I have charted the introduction and development of AR, and I have tried to understand the process of its assimilation and (re)construction within the Mexican setting. The organisation of this thesis reflects the dynamic complexity with which the different actors have constructed the Mexican AR arena. The thesis begins with a description of the theoretical framework and the methodological rationale, followed by a genealogical analysis of Mexican AR focusing on the elements that made its adoption possible, the transformation of gynaecologists into AR specialists, the establishment of AR clinics and services, and the emergence of two new types of AR specialist: the andrologist and the AR biologist. I then analyse the way AR is framed as a paranatural procedure that imitates nature while simultaneously going beyond it and examine the elements that make up what the community of AR specialists suggest are the major causes for infertility: ‘the age factor' and ‘the male factor'. Finally, I describe the pilgrimage AR users embark on in search of parenthood and their quest for information and support. Understanding the process by which AR has been assimilated and transformed in the Mexican context sheds light on the way techno-science is (re)constructed when it arrives in new settings. In addition, this knowledge has the potential to inform local medical and social practices, and regulatory frameworks in the field.

A inseminação artificial (IA) é uma técnica cada vez mais utilizada na suinocultura moderna, pois propicia ao suinocultor vantagens quanto ao desempenho dos reprodutores, ao controle dos cruzamentos e à facilidade na introdução de material genético. Entretanto, a produção de doses inseminantes com qualidade é um dos principais fatores envolvidos no sucesso da técnica. Nesse contexto, a adequada mensuração da concentração espermática do ejaculado suíno é parte fundamental da rotina de trabalho de Centrais de Inseminação Artificial em Suínos. Foram realizados dois experimentos onde se objetivou: Experimento 1 - avaliar a acurácia, a precisão e a robustez do volume do ejaculado do Espermiodensímetro de Karras (ESPM) e do Espectrofotômetro (ESPT), em comparação à Câmara de Neubauer (CN), técnica padrão e também produzir uma tabela de correção de escala do ESPM; Experimento 2 - avaliar o tempo gasto e a repetibilidade de cada técnica, além de comparar a tabela ajustada do ESPM produzida no Experimento 1 com a tabela padrão do ESPM. Utilizaram-se 141 ejaculados, que revelaram concentrações espermáticas médias (milhões de sptz/mL) e número médio de doses que poderiam ser produzidas, respectivamente de 229,1 e 22,6; 185,0 e 18,5; 283,6 e 28,0 para a CN, o ESPT e o ESPM. O viés médio (acurácia) obtido através da média da diferença do resultado da técnica alternativa e da técnica padrão, e o desvio-padrão do viés médio (precisão) do ESPT, em comparação à CN, foram, respectivamente de - 44,1 e 52,6, enquanto que para o ESPM foram de 54,5 e 44,8 (milhões de sptz/mL). Observou-se que o ESPT tende a subestimar e o ESPM a superestimar a concentração espermática, em comparação à CN. O ESPT foi igualmente preciso e mais acurado que o ESPM. Houve pouca influência do volume do ejaculado sobre os resultados do ESPM e do ESPT através dos resultados de robustez para o volume do ejaculado. O ESPM apresentou maior repetibilidade e menor tempo gasto para a realização dos exames, seguido do ESPT e, por último, da CN (P<0,05). A tabela produzida com os dados do Experimento 1 apresentou resultados mais aproximados aos da CN, em comparação com a tabela padrão do ESPM (2,96 bilhões de espermatozóides vivos/dose vs 2,36 bilhões de espermatozóides vivos/dose, respectivamente). Maiores informações de outras Centrais de Inseminação Artificial em Suínos (CIAS) sobre o uso a campo da tabela ajustada produzida, denominada \"Tabela Ajustada para o Espermiodensímetro LPS-FMVZ-USP\", seriam úteis para comprovar a sua eficiência a campo. / Artificial Insemination (AI) in swine is a rising technique that has been used during the last years at the swine production systems, because it furnish several advantages to the producers just like boar high efficiency, better breeding control and easiness in introducing foreign genetic materials. Nevertheless, high quality insemination doses output is one of the most important factors involving the technique success. In this manner, a correct measurement of the spermatic concentration of boars is a basic work routine of the Swine Artificial Insemination Centers (CIAS). Two trials had been performed, whose objectives were: Experiment 1 - evaluate the accuracy, precision and robustness for ejaculation volume of Spermdensimeter (ESPM) and Spectrofotometer (ESPT) in relation to the Neubauer Count chamber (CN), designed as the standard technique. Moreover, produce a scale correction of the ESPM table; Experiment 2 - evaluate the spent time and repetitiousness of each technique, and compare the ESPM adjusted table produced in Experiment 1 with the ESPM standard table. A total of 141 boar ejaculation was used for spermatic concentration measurement by the techniques described above. The average spermatic concentrations (106 sptz/mL) and average doses number were, respectively: 229.1 and 22.6, 185.0 and 18.5, 283.6 and 28.0 for CN, ESPT and ESPM. ESPT mean bias (accuracy) and standard deviation bias (precision), in relation to the CN were, respectively -44.1 and 52.6, while ESPM were 54.4 and 44.8 (106 sptz/mL). Through these results its possible to conclude that ESPT has a tendency to subestimate and ESPM to superestimate the spermatic concentration in relation to the CN. ESPT was more accurate and equally precise than ESPM. Little effect of ejaculation volume on accuracy and precision in both techniques (ESPM and ESPT) was confirmed by the robustness results. ESPM presented a minor coefficient of variation and timeless, followed by ESPT, and finally by CN (P<0,05). The adjusted table produced with Experiment 1 data presented similar results to CN, in relation to the ESPM standard table (2.96 billion of lives sptz/dose vs 2.36 billion of lives sptz/dose, respectively). Complementary data from others CIAS about field use of the ESPM adjusted table produced, named \"Adjusted Table for Karras Spermdensimeter LPS-FMVZ-USP\", would be useful to prove it efficiency.

This study sought to determine: (a) the essential elements of a viable artificial insemination program for the Fulani Tribesmen in Kaduna State, Nigeria, and (b) to determine if the essential elements of a viable artificial insemination program exist in Kaduna State, Nigeria. This study was conducted from April 15 to May 15, 1985, in the Artificial Insemination (AI) Subcenters of Zaria, Katsina, Kabomo, Kaduna, Ikara, Zonkwa, Kurmin-Biri, and Kauranjuli. The data presented in this study were collected by personal interviews with Fulani Tribesmen. The population of this study was from a partial list of Fulani Tribesmen who have had AI performed on their dairy cattle by the cooperative inseminators in the subcenters. The statistical analysis showed an overview of herdsmen reactions to each question. The use of additional statistical tests to determine the degree of significance was not appropriate because the respondents were not randomly selected. The writer did not know in advance the number of Fulani Tribesmen that constituted the total population of the AI system in the subcenters. Noneconomic analysis of this research study includes five linked essential elements of a viable AI program. These elements are: (1) high performance bulls with quality semen, (2) skilled dependable AI technicians, (3) healthy cows, (4) functional communication and transportation resources, and (5) cooperative and informed farmers. This study concluded that four of the five essential elements for a viable AI program currently do not exist for the Fulani Tribesmen in Kaduna State, Nigeria. As a result of this study, it was determined a viable AI program for the Fulani Tribesmen in Kaduna State, Nigeria, is not feasible under the present situation.

The only practical method for artificially breeding ewes with frozen semen is laparoscopic insemination into the lumen of the uterine horn. Like all surgical procedures, however, laparoscopic artificial inseminatiom has limitations. The procedure requires surgical skill and costly equipment. Repeated passage of the laparoscope through the abdominal wall causes adhesions. Depositing frozen/thawed semen at the os cervix results in low conception rates. The inability to pass an insemination pipette through the cervix has prevented artificial insemination in sheep from becoming a standard breeding method as in the cattle industry. This study compared laparoscopic and transcervical methods of insemination in nulliparous ewes and transcervical insemination in multiparous ewes after estradiol cypionate treatment. Forty nulliparous commercial-cross Rambouillet ewes were treated with pessaries containing fluorogesterone acetate to synchronize estrus. After 14 days, pessaries were removed and ewes were injected IM with 400 IU of pregnant mare serum gonadotropin (PMSG). Ewes were randomly divided into laparoscopic and transcervical treatment groups, 14 and 26 respectively. Ewes were inseminated with thawed semen (75x106 motile spermatozoa). Pregnancy rate with laparoscopic insemination was 85% (confirmed at 55 days with real-time ultrasound) .. With the transcervical method, the speculum could only be inserted into the vagina of five ewes and the insemination pipette could only be passed through the cervix in two ewes. The combined pregnancy rate for deep cervical and transcervical insemination was 40% at 55 days. Forty multiparous commercial-cross Rambouillet ewes were synchronized as previously described. Ewes were randomly separated into a control and estradiol cypionate treatment group of 20 animals each. Within each group 10 ewes were inseminated with frozen/thawed Suffolk semen and 1 Owith Rambouillet semen. Ten ewes within each sire genotype were treated with 1 mg IM of estradiol cypionate 16 hours prior to insemination. Treated ewes were inseminated into the uterine body 90% of the time and non-treated ewes 95%. There was no significant difference in cervical passage between these groups. Pregnancy rates for transcervical artificial insemination in the Suffolk genotype were 0.05% and 40% in the Rambouillet (pregnancy confirmed at 55 days by real-time ultrasound). Lambing rates for the Suffolk and Rambouillet groups were zero and 0.05%, respectively.

Abstract Birth of offspring of a pre-determined sex using flow cytometrically sorted fresh spermatozoa was first achieved in rabbits by Johnson et al. (1989). Since then offspring have been produced using sex-sorted spermatozoa from several different species (reviewed by Johnson, 2000). Initially, efficiency of the sex-sorting technology was poor with only low numbers of spermatozoa sorted per hour. Thus, the offspring derived from flow cytometrically sorted spermatozoa were produced with the use of artificial reproductive technologies (ART) such as in vitro fertilisation (IVF) and culture (IVC), intracytoplasmic sperm injection (ICSI) and deep artificial insemination (AI) which facilitated low dose insemination of potentially compromised spermatozoa. More recently, the development of high-speed sorters (Johnson and Welch, 1999) has facilitated the production of offspring using conventional AI techniques with low dose inseminates (Seidel et al., 1999) and successful cryopreservation of sorted spermatozoa (Schenk et al., 1999; Johnson et al., 2000; Lindsey et al., 2002; Schenk and DeGrofft, 2003). Increased efficiency of sorting bull spermatozoa has evolved through significant instrumentation and biological developments which have enabled the commercialization of the sperm sexing technology in the dairy industry, although conception rates in cows after low dose AI with sexed frozen-thawed spermatozoa are still lower than after standard frozen semen AI (Seidel et al., 1999). Subsequently, over 20 000 calves of pre-determined sex have been produced from commercially available sex-sorted frozen-thawed bull spermatozoa (Seidel, 2003). However, similar developments have not been made in the sheep industry and were examined in this thesis. In this study, successful cryopreservation of sex-sorted ram spermatozoa and production of offspring of the pre-determined sex (X: 94.4 %; Y: 100 %) was achieved after low dose (2-4 x 106 total) insemination using conventional laparoscopic intrauterine (IU) AI. However, the overall pregnancy rate for ewes inseminated with sex-sorted frozen-thawed spermatozoa was low (25 %) compared to ewes inseminated with a commercial dose (140 x 106 total) of non-sorted frozen-thawed spermatozoa (54 %). Cryopreservation has been found to not only reduce the proportion of motile spermatozoa, but cause the remaining spermatozoa to undergo changes that advance membrane maturation thereby shortening their lifespan, especially after in vivo fertilisation (Gillan and Maxwell, 1999). It was found that sorting prior to cryopreservation accelerated the maturation of sperm membranes and after co-incubation with oviducal cells in vitro, sorted frozen-thawed spermatozoa were released more rapidly than non-sorted (control) frozen-thawed spermatozoa. The potentially reduced lifespan of sorted frozen-thawed spermatozoa, and practical constraints on the number of spermatozoa that can be sorted for an insemination dose, makes insemination close to the site of fertilisation and time of ovulation critical for successful fertilisation. After treatment of ewes with GnRH to increase the precision of insemination in respect to the time of ovulation, there was no difference in pregnancy rate between ewes inseminated before, during or after the assumed time of ovulation. Furthermore, there was no difference in pregnancy rate after IU AI with similar doses of sorted frozen-thawed and non-sorted frozen-thawed spermatozoa in GnRH-treated ewes. The minimum dose of sorted frozen-thawed spermatozoa required for commercially acceptable pregnancy rates determined after IU AI was high (20 x 106 motile). Consequently, alternative methods for efficiently producing large numbers of offspring of a pre-determined sex using flow cytometrically sorted ram spermatozoa were investigated. Ram spermatozoa can be stored for short periods of time in a chilled state (liquid storage) or for an indefinite period of time in a frozen state (frozen storage; Salamon and Maxwell, 2000). The fixed location of the sperm sorter requires the need for transport of semen from the point of collection to the site of sorting and processing, but also from the sperm sorter site to the recipient females under artificial conditions. In this study, ram spermatozoa liquid stored for 24 h prior to sorting were efficiently sorted, frozen, thawed and after in vitro fertilisation and culture produced a high proportion of grade 1 blastocysts. Similarly, spermatozoa stored at reduced temperatures after sorting maintained high sperm quality for up to 6 days. Furthermore, frozen-thawed spermatozoa from rams and some non-human primates were successfully prepared for sorting and efficiently sorted producing spermatozoa with high quality in vitro parameters. The quality of frozen-thawed ram spermatozoa after sorting was such that successful re-cryopreservation after sorting was possible. Low numbers of frozen-thawed sorted and re-frozen and thawed spermatozoa were optimal for IVF and a high proportion of grade 1 in vitro embryos of a pre-determined sex were produced. These embryos were either transferred immediately or vitrified prior to transfer, extending the application of the sperm sexing technology further. The birth of lambs of pre-determined sex after transfer of both fresh and vitrified embryos derived from frozen-thawed sorted spermatozoa was achieved. The findings in this thesis suggest that sorted frozen-thawed ram spermatozoa may have more advanced membrane maturation state than non-sorted frozen-thawed spermatozoa, resulting in a decreased fertilizing lifespan in the female reproductive tract. Despite this, the use of sexed ram spermatozoa in a number of physiological states (fresh, liquid, frozen) with several different ARTs is possible in producing significant numbers of offspring of a pre-determined sex. Improved efficiency in both sperm sexing and associated reproductive technologies is required for commercialization to be achieved in the sheep industry.

Two trials were conducted to compare the effectiveness of fixed-time artificial insemination (AI) to AI based upon visual detection of estrus following superstimulation of donor beef cows. In Trial 1, multiparous beef cows (n = 31) were randomly allotted to one of three treatments following superstimulation and removal of an intravaginal progesterone insert (CIDR). Cows in the Control group were inseminated at 12 and 24 h after onset of estrus. Cows in the Estradiol group were injected with estradiol-17β (1 mg, im) at 12 h and inseminated at 24 and 36 h after CIDR removal. Cows in the pLH36 group were injected with porcine LH (Lutropin, 12.5 mg, im) at 24 h and inseminated at 36 and 48 h after CIDR removal. Mean numbers of viable embryos were 7.8, 3.6 and 9.6 for Control, Estradiol and pLH36 treatment groups, respectively (P > 0.10). In Trial 2, multiparous beef cows (n = 22) were randomly allotted to one of three treatments following superstimulation and removal of a CIDR. Sixteen of the cows were superstimulated a second time approximately 50 days later and allotted to one of the two treatments that differed from the initial treatment group. Cows in the Control group were inseminated at 12 and 24 h after onset of estrus. Cows in the two pLH groups were injected with porcine LH (Lutropin,12.5 mg, im) at 24 h after CIDR removal and were inseminated with either one unit of semen at 36 and 48 h (pLH36) or with two units of semen at 48 h (pLH48) after CIDR removal. Mean numbers of viable embryos were 3.0, 6.4 and 3.8 for Control, pLH36 and pLH48 treatment groups, respectively (P > 0.10). These data indicate that administration of pLH can facilitate use of fixed-time AI in superovulated beef cows without sacrificing embryo production. The second study evaluated the efficacy of resynchronizing beef cow recipients using CIDR devices for only 7 or 14 d. Recipient cows received CIDRs either on the day of transfer (n = 88) or 7 d post-transfer (n = 230). All CIDRs were removed on d 21 and cows were observed for estrus between d 22 and 24. Cows that displayed estrus were ultrasounded on d 30, those cows not pregnant that possessed a CL had an embryo transferred that day. Cows were later examined for pregnancies approximately 23 to 30 d later. There were no differences in pregnancy rates between cows with 7 or 14 d CIDRs and therefore data were combined. Pregnancy rates at two different ranches indicate that beef cow recipients can be successfully resynchronized by insertion of a CIDR without compromising pregnancy rates of transferred embryos. At Center Ranch the pregnancy rate for the first transfer was 57% while the resynchronized group that received the second transfer had a pregnancy rate of 55%. At Mound Creek Ranch the first transfer of embryos produced 59% pregnancy rates while the second transfer had a pregnancy rate of 71%. No significant differences (P > 0.05) were observed between the pregnancy rates of the initial transfer and those of the resynchronized transfer using only CIDRs, indicating that resynchronization using CIDRs can be used without reducing pregnancy rates.

Two trials were conducted to quantify the effects of GnRH and prostaglandin in conjunction with a 7-d CIDR on estrus and on pregnancy rate in comparison with a traditional synchronization protocol. In trial 1, ewes (n=12) were randomly allotted to one of three treatments: CIDR (7 d) with administration of GnRH (Cystorelin®, 50μg, im) at CIDR insertion and PGF2α (Lutalyse®, 20 mg, im) on d 6.5 (GnRH1); the GnRH1 protocol with a second injection of GnRH 30 h after CIDR removal (GnRH2); and CIDR (11 d) with administration of PGF2α at CIDR insertion and PMSG (400 iu) at CIDR removal (PMSG). A blood sample was obtained every 2 h for 42 h after CIDR removal for serum LH analysis. On d 8 after CIDR removal, blood samples were obtained at 12 h intervals for 36 h for serum P4 analysis. One ewe in the GnRH1 group did not retain the CIDR device and was excluded from the analysis. Mean LH concentration did not differ (P = 0.48) among groups. Time and time x treatment affected (P < 0.001) mean LH concentration. Mean P4 concentration was not affected (P = 0.26) by time, treatment or their interaction. In trial 2, ewes (n=72) were randomly allotted to one of the three treatments described in trial 1. At CIDR removal, three ewes per treatment were joined with a single ram fitted with a marking harness in each of 8 pens. Ewes were monitored every hour for estrus activity and ultrasounded transabdominally 60 d after CIDR removal for pregnancy. Estrus activity did not differ (P > 0.05) among the groups. Marking frequency was 92 percent, 75 percent, and 88 percent for GnRH1, GnRH2, and PMSG groups, respectively. Mean interval to estrus was shorter (P < 0.05) for the GnRH2 than for the PMSG group and tended to be reduced (P < 0.10) compared with the GnRH1 group. Pregnancy rate differed (P < 0.05) among treatments (79 percent, 58 percent and 38 percent for GnRH1, GnRH2, and PMSG groups, respectively). These results indicate that synchrony of estrus and pregnancy rate to natural service can be increased in response to a CIDR protocol when combined with administration of GnRH rather than PMSG.

Thesis (M.C.S.)--Regent College, 1999. / Includes abstract and vita. Includes bibliographical references (leaves 180-186).