Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 2008. / "May 2008" The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Vita. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 110-136). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 110-136). Also available on the Internet.

Thesis (Ph.D. in Molecular Biology) -- University of Colorado at Denver and Health Sciences Center, 2005. / Typescript. Includes bibliographical references (leaves 89-109 and 224-228).

Thesis (M. Sc. (Pharmacy))--Rhodes University, 2006.

Orientador: Eunice Oba / Banca: Roberto Sartori Filho / Banca: Carlos Antonio de Carvalho Fernandes / Resumo: O objetivo do presente estudo foi de avaliar o efeito da aplicação do flunixin meglumine (FM) no momento da inovulação de embriões bovinos sobre a taxa de prenhez de receptoras e identificar o possível mecanismo pelo qual o FM interfere positivamente na taxa de prenhez desses animais. Para tanto, foram realizados dois experimentos, sendo que no experimento 1 foram utilizadas 184 fêmeas cruzadas inovuladas com embriões produzidos in vitro e divididas aleatoriamente em dois grupos experimentais: controle (G1) e grupo FM (G2) onde as receptoras receberam uma aplicação de 1,1 mg/Kg de FM no momento da inovulação. No experimento 2, 22 fêmeas nelore foram divididas aleatoriamente em três grupos: controle (G1); manipulação (G2) onde os 8 animais foram submetidos a manipulação do trato reprodutivo similar a inovulação de embrião no dia 7 do ciclo estral; e grupo manipulação + FM (G3), onde sete fêmeas foram submetidas a manipulação do trato reprodutivo e uma aplicação de FM (1,1 mg/Kg). Os animais dos três grupos foram submetidos a exames ultrassonográficos e colheitas de sangue diárias durante o restante do ciclo estral para determinação da duração da fase luteal e avaliação das concentrações plasmáticas de progesterona. No experimento 1 não foi observada diferença na taxa de prenhez dos animais no grupo controle e grupo FM (40,2% e 44,6%, respectivamente) (p = 0,55). No experimento 2 não foi observada diferença significativa na duração da fase luteal do ciclo estral entre os grupos experimentais, porém foi observado que os animais do grupo manipulação apresentaram valores médios para as concentrações plasmáticas de progesterona inferiores quando comparados aos valores observados nos grupo controle e manipulação + FM. Dessa forma, foi observado efeito positivo da aplicação do FM no momento da inovulação sobre a concentração plasmática... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate the effects of an administration of flunixin meglumine (FM) at the moment of bovine embryo transfer on pregnancy rates of recipients and also to determine the possible mechanisms by which FM improves the pregnancy rates of these animals. Therefore two experiments had been carried out in a way that in experiment 1 184 crossbreed females were transferred with an in vitro produced embryo and randomly divided into two experimental groups: control group (G1) and FM group (G2) in which recipients received one administration of 1.1 mg/Kg of FM at the moment of embryo transfer. In experiment 2, 22 nelore females were randomly divided into three groups: control (G1), manipulation (G2) in which animals were submitted to a reproductive tract manipulation (similar to an embryo transfer) at day 7 of the estrous cycle, and manipulation + FM group (G3) in which females were submitted to a reproductive tract manipulation and an administration of FM. To determine the length of luteal phase and evaluate the progesterone release profile of the corpus luteum, animals of the three groups were submitted to successive ultrasound examinations and blood sample collections during the rest of the estrous cycle. In experiment 1 no significant difference was observed on the pregnancy rates of animals of control group and FM group (40.2% and 44.6%, respectively). In experiment 2 no significant difference was observed on the length of the luteal phase of the estrous cycle between experimental groups, however animals of manipulation group presented lower average values of plasma progesterone concentrations when compared to average values observed on control group and manipulation + FM group. Thus a beneficial effect of the administration of FM at the time of embryo transfer over the plasma progesterone concentration was observed, however, no significant difference was observed on the pregnancy rates of treated animals. / Mestre

Ethiopia maintains an extensive livestock population; however, reproductive performance of cattle and their breeding management are unsatisfactory. Currently, the sole diagnostic tool in the country is rectal palpation, which is inaccurate for early pregnancy in cattle. The study assessed reproductive performance and major reproductive problems using questionnaire survey, and evaluated simple, cost-effective alternative monitoring approaches using on-farm diagnostic tools to determine milk and serum progesterone (P4) and evaluate reproductive status. There were 177 dairy farms (range 1-115 cattle per farm) included in the questionnaire survey. Of these, 47 participated in the quantitative determination of P4 and estradiol profiles that used an enzyme-linked immunosorbent assay (ELISA) and in the on-farm diagnostic trial that used qualitative ELISA (Target P4 and Dipstick (P4 Rapid), and the reproductive status of 319 crossbred [Holstein Friesian (HF) X Zebu] dairy cattle was assessed. Questionnaires indicated that heifers in the study area reach puberty at older age and calve late, and cows have long postpartum estrus and calving interval. Anestrus, repeat-breeding, dystocia, retained fetal membranes (RFM), endometritis and abortion as the major reproductive problems in dairy cattle in the study area. Serum, milk, saliva and urine P4 and serum estradiol profiles of cattle at different reproductive status was determined using quantitative laboratory ELISA. High P4 levels was detected in pregnant and diestrus cattle than cattle that were anestrus and in-heat. Estradiol level was higher in cattle that were in-heat than cattle in other reproductive conditions. On-farm P4 ELISA indicated in-heat (estrus) 10 (3.1%), anestrus 77 (24.2%), repeater (follicular cyst) 9 (2.8%), normally cycling 69 (21.6%) and pregnant 154 (48.3%). The field P4 ELISA findings were validated using quantitative laboratory P4 ELISA, and similar results were obtained. The sensitivity and specificity of on-farm and laboratory P4 ELISA tests for diagnosing pregnancy were 88.6 & 99.4% and 98.1 & 100%, respectively. Once reproductive problems were identified using on-farm P4 ELISA and per rectal palpation, along with reproductive history, 122 cattle (75 cows and 47 heifers) were assigned to a 10-day Controlled Internal Drug Release (CIDR) in combination with prostaglandin F2-alpha (PGF2α) and equine chorionic gonadotrophin (eCG) based estrus synchronisation protocol to study the estrus response and conception rate. The overall estrus response and conception rates were 97.5% and 78.3%, respectively, with no significant differences in parity, pre-treatment reproductive status (anestrus or cycling (repeat-breeding/silent-estrus)) and farming system (smallholder vs organised commercial farms). The study has shown high estrus response and conception rate. Hence, this protocol is highly recommended to enhance fertility of dairy cattle in the study area and other regions. Finally, the study has determined the macronutrient composition of milk and assessed the effect of reproductive status, farm (nutritional) management, stages of lactation, parity and breed on milk composition in 246 dairy cows. This consisted of 184 crossbred cows from smallholder (n= 76: 36 non-pregnant and 40 pregnant) and organised commercial dairy farms (n= 108: 62 non-pregnant and 46 pregnant) in and around Mekelle, Ethiopia and by way of comparison, 62 HF cows (25 non-pregnant and 37 pregnant), either managed indoors or outdoors in a commercial farm in Edinburgh, United Kingdom. The mean milk fat, protein, lactose, total solid (TS) and solid-no-fat (SNF) recorded were 2.36%, 3.46%, 4.37%, 10.39% and 7.82%, in crossbred dairy cows, compared with 5.05%, 3.71%, 4.72%, 13.68% and 8.43%, in HF cows, respectively. Significantly lower (p < 0.05) level of macronutrient was recorded in milk from crossbred cows than HF cows. Milk fat in both breeds was affected by reproductive status, farm (nutritional) management and stages of lactation, but not by parity. In both cattle breeds, the milk fat content was significantly higher (p < 0.05) in pregnant than non-pregnant cows. Milk protein content was significantly (p < 0.05) affected by reproductive status (in crossbreds) and stages of lactation (in both breeds), but not by farm management or parity. Reproductive status (in crossbreds), stages of lactation (in both breeds) and parity (in crossbreds) affected lactose level; however, farm management had no effect on lactose level in both breeds. Milk fat was the most affected macronutrient content in both breeds. Low milk fat level in crossbred cows could be as a result of samples obtained from early milking coupled with nutritional management. In conclusion, the present study has determined the major reproductive problems in crossbred dairy cattle, assessed their actual reproductive status using rapid, cost effective, simple and applicable on-farm P4 tests, and established P4 and estradiol profiles at different reproductive status. The major breeding problem was poor estrus detection evidenced when animals reported anestrus were confirmed normally cycling using on-farm as well as laboratory P4 assays. These studies offer opportunities for establishing simple field reporting of reproductive status in these crossbred dairy cattle, which can have a major impact on breeding management and productivity.

O experimento 1 verificou o efeito de um protocolo de indução e sincronização de estros em novilhas sobre a cronologia das parições e a repetição de crias como primíparas. 194 novilhas Hereford e Braford foram divididas em 2 grupos: Tratamento, submetido a um protocolo misto de observação e sincronização de estros e inseminação artificial a tempo fixo (IATF); e Controle, submetido ao manejo convencional de inseminação artificial (IA). Ambos grupos foram submetidos a repasse por touros. O Experimento 2 avaliou o efeito de um pré-tratamento com norgestomet (NOR), prévio a um protocolo de sincronização para IATF em novilhas, sobre as taxas de prenhez, assim como os efeitos de características relacionadas com a reprodução. 74 novilhas Angus e cruzas, 18 e 24 meses de idade, com peso médio de 276 kg, condição corporal (CC) mínima de 3 (1-5) e avaliadas por ultra-som para o status ovariano, onde utilizaram-se somente novilhas 2 e 3 (1-3). Pesagens a cada 30 dias, desde os 60 dias anteriores aos serviços. Coletado sangue para dosagem de progesterona. Os animais foram divididos em 2 grupos: Tratamento, que recebeu um implante com 6 mg de NOR, na orelha direita, permanecendo por 14 dias; e Controle, que não recebeu implante. Dez dias após a retirada dos implantes, todas as novilhas foram a um protocolo para IATF, com uma injeção de GnRH, 7 dias depois uma aplicação de prostaglandina (PGF) e 48 horas mais tarde, as IATF e outra aplicação de GnRH. Quatorze dias após iniciou-se repasse com 2 touros, por mais 45 dias. O Experimento 3 avaliou o efeito da suplementação com progestágeno (acetato de medroxi-progesterona; MAP) ou progesterona, anteriormente a um protocolo para IATF, e verificou o efeito de características associadas à reprodução de novilhas, e de distintos manejos alimentares sobre as taxas de prenhez. Utilizaram-se 102 novilhas Angus, cruzas Angus e Braford, 22-24 meses, peso médio 241 kg e CC mínima de 2,5. Pesagens a cada 30 dias, a partir dos 60 dias anteriores aos serviços e ultra-som para o status ovariano (1-3). Quarenta e cinco dias antes da estação foram divididas em 2 grupos, Sem Suplementação, com 27 novilhas exclusivamente sobre pastagem natural, e Com Suplementação, com 75 novilhas consumindo 1% do peso em concentrado. Coletas de sangue para dosagem de progesterona. Grupos novamente divididos em 3, para receber dispositivo com progesterona, ou uma esponja intravaginal com MAP, ambos por 10 dias. O grupo Controle não recebeu nenhum tratamento. Na retirada dos implantes, todas as novilhas receberam PGF, e 4 dias depois, foram a um protocolo para IATF, com 2 mg de benzoato de estradiol na colocação de uma esponja com MAP. Sete dias depois, a esponja foi retirada, sendo aplicada PGF, seguindo-se nova aplicação de BE 24 horas depois, e IATF 52-56 horas após a PGF. Observação de estros 2 vezes por dia, desde a PGF até a IATF. Passados 14 dias, iniciou repasse por 4 touros, durante 45 dias. O Experimento 4 avaliou o efeito da suplementação de novilhas de corte com gammaorizanol, sobre o desempenho reprodutivo, assim como o efeito de outras características sobre a reprodução. Utilizaram-se 84 novilhas Angus, Hereford, Braford e Angus x Hereford, com 24 meses, peso médio de 283 kg e CC ≥ 3. Pesagens a cada 30 dias, desde 60 dias antes até o início dos serviços, coletas de sangue para dosagem de progesterona. Duas avaliações da espessura de gordura subcutânea, sobre a região P8 por ultra-som, com intervalo de 30 dias. Animais foram divididos em 2 grupos: Tratamento, que recebeu desde 45 dias antes até o início da estação reprodutiva, 150 ml/dia de gamma-orizanol junto à 1 kg de concentrado; e Controle, com 150 ml/dia de melaço, junto à 1 kg do mesmo concentrado. Observações de estros 2 vezes/dia e IA. Dez dias após aplicou-se PGF a todas ainda não observadas em estro, prosseguindo-se a observação e IA por mais 25 dias. Após, repasse por 2 touros por 45 dias. Diagnósticos de gestação por ultra-som, 30 dias após as IATF ou IA, e novamente, 30 dias depois de retirados os touros. No experimento 1, a porcentagem de prenhez na primeira estação reprodutiva foi semelhante para os 2 grupos. Entretanto, a repetição de crias nas primíparas do grupo Tratamento foi significativamente maior. No Experimento 2, não foram observadas diferenças entre as taxas de prenhez à IATF e final, e conforme a idade e o status ovariano. No Experimento 3, taxas de estro superiores para o grupo Progesterona em relação ao Progestágeno e Controle. Entretanto, taxas de prenhez semelhantes entre os grupos. Foi encontrada diferença entre o peso 24 dias antes dos serviços, para as novilhas que emprenharam em relação às que permaneceram vazias e para os pesos das novilhas ao final da temporada. As novilhas com status ovariano 2 e 3 foram mais pesadas em relação ao 1, mas as taxas de prenhez não diferiram com o status ovariano. O concentrado proporcionou superior GMD para o grupo Com Suplementação, mas sem diferenças para as taxas de prenhez. No Experimento 4, taxas de prenhez semelhantes para Tratamento e Controle. Novilhas prenhas foram as que acumularam maior quantidade de gordura na região P8. Concluindo, o manejo com sincronização de estros e IATF na primeira estação reprodutiva em novilhas, apesar de apresentar índices idênticos de prenhez ao final da temporada, proporcionou diferença significativa nos índices de prenhez na segunda estação. O pré-tratamento com norgestomet não proporcionou superiores taxas de prenhez em novilhas. Da mesma forma, o priming com progesterona ou MAP, não proporcionou taxas de prenhez superiores, assim como a utilização de suplementação alimentar. O peso corporal antes ou dos serviços, foi superior para as novilhas que emprenharam. Novilhas com status ovariano 2 e 3, foram mais pesadas. O fornecimento de gamma-orizanol não proporcionou superiores taxas de prenhez ou peso corporal, entretanto, novilhas que resultaram prenhas, acumularam maior quantidade de gordura antes da estação reprodutiva. / Experiment 1 verified the effect of an estrus synchronization protocol in heifers on parturition chronology and primiparous reproductive performance. 194 Hereford and Braford heifers were divided into 2 groups: Treatment group, submitted to an estrus observation and synchronization to fixed-time artificial insemination (FTAI) protocol; and Control group, submitted to a conventional artificial insemination (AI) management. All groups were submitted to a bull’s clean-up period. Experiment 2 evaluated the norgestomet (NOR) priming effect, before a fixed-time artificial insemination protocol (FTAI) in heifers, on pregnancy rates, as well as the effects of reproductive related characteristics. 74 Angus and cross-bred heifers, 18 and 24 months old, with 276 kg of body weight, body condition score (BCS) minimum of 3 (1- 5), and ovarian status evaluated by US. Only the 2 or 3 class heifers were used (1-3). Heifers were weighted at 30 days intervals, starting 60 days before the reproductive period. Blood was collected for progesterone assay. Heifers were divided in 2 groups: Treatment group, that received an ear implant with 6 mg of NOR, in the right ear, removing it 14 days after; and Control group, did not receive the implant. Ten days after the implants removal, all heifers were submitted to FTAI protocol, which including a GnRH i.m. injection, 7 days after the prostaglandin (PGF) aplication, and 48 hours later, FTAI and a second GnRH injection. Fourteen days later, started a clean-up period with 2 bulls, for 45 days more. Experiment 3 evaluated the progestin (medroxiprogesterone acetate; MAP) or progesterone suplementation effect, before a FTAI protocol, and evaluated the effects of reproductive associated characteristics in heifers, and feeding managements over pregnancy rates. 102 Angus, cross-bred Angus and Braford heifers, 22-24 months old were used, with an average body weight of 241 kg, and a minimum BCS of 2,5. Heifers were weighted at 30 days intervals, starting 60 days before the breeding period and an ecography was performed to evaluate ovarian status. Fourty five days before the season, heifers were divided into 2 groups. Without Suplementation group, with 27 heifers, only over natural pastures, and With Suplementation group, with 75 heifers receiving suplementation (72% TDN and 15% GP) about 1% body weight. Blood was collected for progesterone assay. Groups were again divided into 3, to receive a progesterone device or an intravaginal MAP sponge, for 10 days. The Control group, not received the treatment. At the implants removal, all heifers received PGF, and 4 days later were submitted to a FTAI protocol, with 2 mg estradiol benzoate with an intravaginal MAP sponge aplication. Seven days later, the sponge was removed, and PGF was injected, with a new EB injection, 24 hours later, and FTAI 52-56 hours after PGF. Estrus was observed from PGF injection to FTAI. A clean-up period started 14 days after with 4 bulls, for more 45 days. Experiment 4 evaluated the gamma-orizanol suplementation effects and other reproductive associated characteristics on fertility of beef heifers. 84 Angus, Angus x Hereford, Hereford and Braford heifers, 24 months old were used, with an average body weight of 283 kg and BCS ≥ 3. Heifers were weighted at 30 days intervals, to register ADG, and blood samples were collected for progesterone assay. Two subcutaneous fat thickness ecographic evaluations were performed at P8 region, with a 30 days interval. Animals were divided into 2 groups: Treatment group, that received 150 ml/day of gammaorizanol with 1 kg of concentrate since 45 days before the reproductive season start ; and Control group, with 150 ml/day of molasses with 1 kg of concentrate during the same period. Estrus control was done twice for day with AI of estrous heifers. Ten days later PGF was applied to all heifers that did not show estrus. The AI management continued for 25 days. In sequence, a clean-up period with 2 bulls was performed for 45 days. Gestational diagnostics by ecography at 30 days after FTAI, and again at 30 days after bulls removal. In experiment 1, pregnancy rates were similar between groups after first reproductive season. However, the repetition of Treatment group was significantly higher. In Experiment 2, were not observed differences between groups in FTAI and final pregnancy rates, without differences for age or ovarian status In Experiment 3, Progesterone group presented the higher estrus rates than Progestin and Control groups. However, were not observed differences in pregnancy rates among the groups. At the same experiment, difference on weights before mating was found between the heifers that became pregnant compared to heifers that stayed non pregnant. Heifers with ovarian status 2 and 3 had higher average weight than heifers with status 1. The suplementation enhanced ADG in the With Suplementation group, but it did not produce differences on pregnancy rates. In Experiment 4, pregnancy rates were similar between groups. Heifers which became pregnant acumulated more fat amount in P8 region, during the treatment period. In conclusion, the first breeding season management with synchronization to FTAI in heifers, since being presented identical final pregnancy rates, produced signifficative differences on pregnancy rates in the second breeding season. The priming with norgestomet did not enhance pregnancy rates in beef heifers, as well the progesterone or progestin primings and the different feeding managements. Heifers with ovarian status 2 and 3, had higher body weights. Gamma-orizanol supplementation did not enhanced pregnancy rates, ADG neither body weight. Heifers that became pregnant, acumulated more fat amount on P8 region before the reproductive season.