A raça crioula Pé-duro do Piauí (Bos taurus) é extremamente bem adaptada às condições ambientais desfavoráveis da zona semi-árida do Nordeste Brasileiro e está em risco de extinção. Neste trabalho foi caracterizada geneticamente, por microssatélites, uma amostra (n=126) originária da Fazenda Experimental Octavio Domingues, da Embrapa Meio-Norte, no município de São João do Piauí. A variabilidade genética foi estimada através de freqüências gênicas, diversidade gênica, heterozigose esperada e observada, riqueza alélica, valor do Pic (conteúdo de informação de polimorfismo), coeficiente de endogamia e verificação do equilíbrio de Hardy-Weinberg. Os locos analisados foram SPS115, BM1824, BM2113, BMS4049, TGLA122, ETH225, ETH10, INRA23, UWCA46 e BMS348, identificando-se um total de 101 alelos. A diversidade gênica média foi de 75,6%, com valores extremos verificados nos locos TGLA122 (91,3%) e BMS4049 (45,4%). O valor médio da heterozigose esperada foi 75,5%, observada 60,0%, e Pic 72,3%. O coeficiente de endogamia Fis foi estatisticamente significativo (Fis=0,206; P<0,01). Foram observados também desvios do equilíbrio de Hardy-Weinberg em nove dos dez locos analisados. A partir dos dados obtidos foi possível observar que ainda existe diversidade genética nesta população, porém os desvios do equilíbrio, o valor significativo do Fis, e a heterozigose observada menor em todos os locos em relação à esperada, demonstraram a ocorrência de cruzamentos endogâmicos resultando em alto nível de homozigose nesta população. / The Pé-duro creole breed is well adapted to the unfavorable environmental conditions of the semiarid zone of Northeastern Brazil and it is in extinction danger. In this work we tried to characterize genetically a sample (n=126) collected at the Embrapa Meio-Norte, located in São João do Piauí city. We examined heterozygosity, polymorphism information content (Pic), allelic frequency and genetic diversity, allelic richness, inbreeding coefficient and Hardy-Weinberg equilibrium. Ten loci were used SPS115, BM1824, BM2113, BMS4049, TGLA122, ETH225, ETH10, INRA23, UWCA46 and BMS348 and a total of 101 alleles were identified. The largest genetic diversity was verified in the locus TGLA122 (91,3%), and the smallest in the locus BMS4049 (45,4%). The mean expected heterozygosity was 75,5%, the mean observed heterozygosity was 60,0%, and the mean Pic value was estimated as 72,3%. We also observed a significant inbreeding coefficient (Fis) for this population (Fis=0,206 P<0,01) and deviations from the Hardy-Weinberg equilibrium in nine of the ten analyzed loci. Considering the obtained data it was possible to infer that genetic diversity still exists in this population, however the deviations from Hardy-Weinberg equilibrium, significant inbreeding coefficient, and the smaller observed heterozygosity in all of the loci showed the occurrence of high degree of inbreeding in this population.

Objetivou-se com este estudo compreender as dinâmicas das temperaturas corporais em fêmeas da raça Nelore, e relacionar os aspectos fisiológicos da termorregulação com as respostas celulares pela expressão de proteínas de choque térmico. O projeto foi desenvolvido no Laboratório de Biometeorologia e Etologia, da Faculdade de Zootecnia e Engenharia de Alimentos da Universidade de São Paulo, Pirassununga-SP. Foram utilizadas 20 vacas Nelore pluríparas, cíclicas, mantidas em sistema de pastejo. O período experimental precedeu a estação de monta de 2013 e terminou na inseminação artificial. Para classificar os animais quanto ao gerenciamento de calor foi monitorada a temperatura vaginal durante seis dias por meio de 16 data loggers (n=16). Com o intuito de melhor compreender o gerenciamento de calor, outras respostas fisiológicas, nomeadamente temperatura retal, caudal, ocular, frequência respiratória e taxa de sudação foram colhidas durante os quatro dias finais do monitoramento da temperatura vaginal. Para expressão gênica relativa colheram-se amostras de sangue (n=20). Foram realizados choques térmicos in vitro a 38ºC, 40ºC e 42ºC por duas horas. Após tratamento térmico obteve-se o pellet de leucócitos para posterior extração do RNA pelo método TRIzol. Foram escolhidas 10 vacas com os melhores resultados de concentração de RNA, 5 pertencentes ao grupo de vacas eficientes quanto ao gerenciamento de calor, e 5 não eficientes (n=10). A RT-PCR foi realizada com o kit SuperScript III. A reação polimerase em cadeia em tempo real (qPCR) ocorreu no aparelho StepOnePlus® Applied Biosystem utilizando como marcador fluorescente o SYBR® Green para os genes alvo validados HSPA1A, HSPD1, HSP90AA1, HIF1A e endógenos ACTB, RPL15 e PPIA. Os dados foram analisados por ANOVA, regressão e correlação do SAS 9.2. As vacas foram classificadas em eficientes e não eficientes por meio de coeficientes angulares, advindos da regressão das temperaturas vaginais durante períodos de ganho e perda de calor. As vacas eficientes apresentaram menores temperaturas retais 37,65ºC (P<0,01) e maior taxa de sudação 528,73 g. m-². h-¹ (P<0,06). A nível celular, o aumento programado in vitro da temperatura não aumentou quantidade de transcritos, promovendo manutenção à 38ºC e 40ºC e declínio à 42ºC. A ordem decrescente da abundância de transcritos foi HSPA1A, HSPD1 e HSP90AA1. Pode-se concluir que vacas Nelore com diferentes gerenciamentos de calor apresentam respostas termorregulatórias diferentes. A HSPA1A apresentou a maior abundância de transcritos sendo considerada como marcador molecular para termotolerância, por ser a mais sensível à temperatura e bem conservada. Não foi observado diferença nas expressões gênicas relativas das proteínas de choque térmico entre os animais classificados quanto ao gerenciamento de calor. / The aim of this study was to understand the dynamics of body temperatures in Nellore females, and relate the physiological aspects of thermoregulation with cellular responses by the expression of heat shock proteins. The project was developed in Biometeorology and Ethology Laboratory, Faculty of Animal Science and Food Engineering, University of São Paulo, Pirassununga-SP. Were used 20 Nellore pluriparous cows, cyclical, kept in grazing system. The experimental period preceded the 2013\' breeding season and ended up in artificial insemination. To classify animals in relation to heat management the vaginal temperature was monitored for six days through 16 data loggers (n=16). In order to better understand the heat management, other physiological responses, including rectal, tail and eye temperatures, respiratory rate and sweating rate were taken during the final four days of vaginal temperature monitoring. For gene expression was harvested blood samples (n=20). in vitro heat shocks were performed at 38ºC, 40ºC and 42ºC during two hours. After the heat treatment was obtained the leukocyte pellet for later RNA extraction by TRIzol method. Ten cows were chosen with the best RNA concentration results, five belonging to the group of cows efficient on heat management and five inefficient (n = 10). RT-PCR was performed with SuperScript III kit. The real-time polymerase chain reaction (qPCR) occurred in StepOnePlus® Applied Biosystems instrument using the SYBR® Green as fluorescent marker to the target validated genes HSPA1A, HSPD1, HSP90AA1, HIF1A and the endogenous ACTB, RPL15 and PPIA. Data were analyzed using ANOVA, regression and correlation SAS 9.2. The cows were classified as efficient and inefficient through angular coefficients, derived from regression of vaginal temperatures for the gain and heat loss periods. Efficient cows had lower rectal temperature 37.65ºC (P<0.01), higher sweating rate 528.73 g. m ². h-¹ (P<0.06). At cellular level, the increase of in vitro programmed temperature has not increased the transcripts amount, promoting the maintenance at 38ºC and 40ºC and decline at 42ºC. The decreasing order of transcripts amount was HSPA1A, HSPD1 and HSP90AA1. It can be concluded that Nellore cows with different heat managements has different thermoregulatory responses. The HSPA1A showed the highest transcripts abundance being considered as a molecular marker for thermotolerance, for being more sensitive to temperature and better conserved. There was no difference in gene expression for heat shock proteins between animals classified by heat management.

A espécie Bos indicus, particularmente a raça Nelore, é grande maioria no rebanho bovino da região acima do trópico no Brasil. Embora a habilidade desses animais em resistir às doenças parasitárias, condições climáticas e pastagens de baixa qualidade enalteçam a utilização em larga escala desta raça, estes animais não são considerados bons conversores de alimento e, conseqüentemente, precoces em comparação aos seus homólogos Bos taurus. Durante a formação das raças zebuínas brasileiras, houve uma participação das linhas maternas de Bos taurus, que pode ser demonstrada pela contribuição majoritária do genoma mitocondrial desta subespécie. Embora em escala muito menor, estima-se que exista também uma participação destas linhas maternas no genoma nuclear. O objetivo deste trabalho foi iniciar os estudos para estimar esta participação. Para os estudos foram utilizados 104 animais da raça Nelore e 8 animais de diferentes raças européias. Cinco regiões do DNA que produzem fragmentos microssatélites taurus/indicus específicos (HEL1, HEL9, ETH225, ILSTS005 e INRA063) foram amplificadas com a utilização de primers marcados com sondas fluorescentes. Os fragmentos foram submetidos à eletroforese em gel de poliacrilamida desnaturante 6% e visualizados após excitação com laser. No total foram encontrados 23 alelos para os microssatélites analisados o que representa uma média de 4,6±1,82 alelos por locus. Amplificou-se também uma região do DNA satélite 1711b que posteriormente foi digerida com a enzima de restrição Msp I. Verificou-se a existência de três possíveis genótipos entre os animais Nelore mtDNA Bos taurus e mtDNA Bos indicus. Os animais europeus analisados apresentaram sempre o mesmo padrão de restrição. A comparação dos componentes de variância do tamanho dos alelos intra e inter população usando os fragmentos microssatélites permitem a separação dos animais Bos taurus dos animais Nelore, mas não dos Nelore de origem materna distinta. No entanto, a freqüência de alelos indicus específicos nos microssatélites e de padrões de digestão do DNA satélite também indicus específicos sugerem uma participação da ordem de aproximadamente 6% do genoma taurus na população de gado Nelore. / Bos indicus specie, especially Nellore breed is responsible for the majority of Brazilian tropical herd. These animals are notably capable to endure parasite infection as well as hot weather and low quality feed. In one hand this qualities suggest the large scale application of this breed, but in other hand this same breed is well characterized as bad food converter and consequently far from having good precocity status compared with its Bos taurus homologues. It has been reported a matrilineal European participation in Zebu cattle since its introduction in American lands. This hybridization is confirmed by the majority contribution of Bos taurus mtDNA in these animals. Although in a much lower frequency, we hypothesize a Bos taurus cow participation in nuclei genome. The main aim of this work was to give the firsts steps towards the estimation of this participation. A total of 104 Nellore and 8 animals of different European breeds were used for DNA analysis. Five microsatellites fragments (HEL1, HEL9, ETH225, ILSTS005 e INRA063) were amplified applying primers with fluorescent dye. Amplified fragments were used in 6% polyacrilamide electrophoresis and visualized after laser excitation. Overall 23 alleles were detected averaging 4.6±1,82/locus. Variance components of microsatellites allele size comparisons allowed the formation of two clusters separating both subspecies. No significant variation was observed between Nellore with different maternal origins. A satellite 1711b DNA was also amplified and digested with the restriction enzyme Msp I. Three possible genotypes were identified in Nellore animals harboring B. taurus and B. indicus mtDNA. European originated animals always showed the same restriction pattern. Finally B. indicus specific microsatellite allele and satellite 1711b digestion patterns frequency allowed the estimation of 6% of B. taurus contribution in purebred Nellore. These results are discussed in terms of application in cattle genetic improvement.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2016-12-20T10:33:59Z No. of bitstreams: 2 Tese - Gisele Aparecida Felix - 2016.pdf: 1558360 bytes, checksum: 761cc39345caea8787f3f1e6a9816a8c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-12-27T12:47:48Z (GMT) No. of bitstreams: 2 Tese - Gisele Aparecida Felix - 2016.pdf: 1558360 bytes, checksum: 761cc39345caea8787f3f1e6a9816a8c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-12-27T12:47:48Z (GMT). No. of bitstreams: 2 Tese - Gisele Aparecida Felix - 2016.pdf: 1558360 bytes, checksum: 761cc39345caea8787f3f1e6a9816a8c (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2016-06-24 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Outro / Trichology is a method to analyze micro-structural patterns of scarf-skin scales arrangements and medullary cells found in mammals guard hair. The present study was conducted to identify Caracu, Curraleiro Pé-Duro, Pantaneiro and Nellore bovine breeds by trichological morphology and morphometry, as well as validate the technique compared with genetic characterization. This study was presented in chapters. First, a review on trichology application on mammal species and breeds identification with basic concepts necessary for understanding trichology analysis and its applications. The second chapter was composed by characterization of guard hair of Caracu, Curraleiro Pé-Duro and Pantaneiro (Bos taurus taurus) and of Nellore (Bos taurus indicus), Brazilian bovine breeds, through trichology analysis, to assess the possibility of using this technique as a racial marker. Morphological and morphometric descriptions were held by 160 cattle (40 animals/breeds). Sub-samples of each bovine were made until quality slides were obtained. Morphology was determined through dichotomous keys and measures were carried out in the cuticle scale and in the hair shield matrix. Results indicated that trichology and genetic evaluation were similar in the point of view of classification of individuals within racial groups. Therefore, the technique can be considered useful as a marker for bovine breeds. / A tricologia é um método que permite analisar os padrões microestruturais de arranjos de escamas cuticulares e células medulares encontradas em pelos guarda de mamíferos. O presente estudo foi conduzido com o objetivo de identificar as raças bovinas Caracu, Curraleiro Pé-Duro, Pantaneiro e Nelore por meio da morfologia e morfometria tricológica, bem como validar a técnica comparando com resultados da caracterização genética. Esse estudo foi apresentado em forma de capítulos, com uma revisão de literatura sobre a aplicação da tricologia na identificação de espécies de mamíferos e de raças de interesse zootécnico, onde foram disponibilizadas informações sobre os conceitos básicos necessários ao entendimento da análise tricológica e suas aplicações. O capítulo seguinte foi composto pela caracterização de pelos guarda das raças bovinas Caracu, Curraleiro Pé-Duro e Pantaneiro (Bos taurus taurus) e da raça Nelore (Bos taurus indicus), por meio de análise tricológica, a fim de avaliar a possibilidade de uso desta técnica como marcador racial. Realizaram-se descrições morfológicas e morfométricas dos pelos de 160 bovinos (40 animais/raça). De cada bovino foram feitas subamostras de pelos até serem obtidas lâminas de qualidade. A morfologia foi determinada por meio de chave dicotômica e as medidas foram realizadas na escama cuticular e na medula e os resultados dessa metodologia foram comparados à caracterização genética dos animais amostrados. Os resultados indicaram que a tricologia e a avaliação genética foram similares no ponto de vista de classificação dos indivíduos dentro dos grupos raciais. Portanto, a técnica pode ser considerada útil como marcador racial para raças bovinas.

O projeto teve como objetivo avaliar os efeitos da inclusão do ionóforo narasina no suplemento mineral e proteinado sobre o consumo de suplemento pelos animais e sobre o desempenho de bovinos de corte durante a fase de recria mantidos em pastagem. Foram utilizados 150 machos nelore inteiros em um delineamento experimental de blocos completos, sendo a unidade experimental o lote de 5 animais. O experimento teve duração de 140 dias, composto por 5 perídos de 28 dias cada. Os tratamentos utilizados foram: CON Mistura mineral Controle (sem narasina), 1800 CON com adição de 1800 mg de narasina/kg da mistura mineral, 2750 - CON com adição de 2750 mg de narasina/kg da mistura mineral, PROT Suplemento Proteinado com 22% de proteína bruta (PB; sem narasina) e PROT 360 PROT com 360 mg de narasina/kg do suplemento. Os tratamentos foram confrontados através de contrastes ortogonais. A inclusão de narasina na mistura mineral aumentou o ganho médio diário (GMD) quando comparado ao CON no primeiro período (P = 0,01; 28d), entretanto, não houve efeito nos demais períodos. A inclusão de narasina diminuiu o consumo de suplemento nos três períodos iniciais (P &lt; 0,01 para ambos) quando comparado ao CON. Os tratamentos 1800 e 2750 foram semelhantes para a ingestão de suplemento (P = 0,89) e GMD (P = 0,70) em todo o experimento. Os animais dos tratamentos PROT e PROT 360 consumiram mais suplemento em relação aos animais dos tratamentos com mistura mineral (P &lt; 0,01 para todos os períodos) e proporcionaram animais mais pesados (P &lt; 0,01). A inclusão de narasina no suplemento proteinado otimizou seu uso nos dois primeiros períodos, pois obteve o mesmo GMD (P = 0,75 e P = 0,48, respectivamente), porém com menor ingestão de suplemento (P = 0,03 e P &lt; 0,01, respectivamente). Em conclusão, a narasina afeta o consumo de suplementos e desempenho em situações específicas, porém, de maneira geral a narasina não foi eficaz em melhorar a performance de bovinos de corte em fase de recria a pasto. / The present trial was carried out to evaluate the effect of narasin inclusion in mineral and protein supplements in the supplement intake and performance of grazing beef cattle. A hundred and fifty Nellore bull calves with 17.03 &#177; 0.06 months of age, initial body weight (BW) of 219.65 &#177; 1.62 kg, were assigned to the following treatments: mineral supplement (CON); mineral supplement + 1800 (1800) or 2750 (2750) mg narasin/kg of supplement; Protein mineral supplement (PROT) or PROT + 360 mg of narasin/kg of supplement (PROT 360). The bull calves were kept in a rotational stocking system with Brachiaria brizantha cv Marandu, during 5 periods of 28 days each. Adding narasin in the mineral supplement increased (P = 0.01) average daily gain (ADG) on the 1st period and decreased (P &lt; 0.01) supplement intake on the 1st, 2nd and 3rd periods compared to CON. Bull calves in the 1800 and 2750 treatments had similar supplement intakes (P = 0.89) and ADG (P = 0.70) at the end of the experiment. In addition, the animals of the PROT and PROT 360 treatments consumed more supplement than the animals of the mineral mix treatments (P &lt; 0.01 for all periods) and provided heavier animals (P &lt; 0.01). Narasin decreased the protein supplement intake and did not affect ADG on the 1st and 2nd periods. The narasin affects the intake of supplements and performance in specific situations, however in overall, narasin addition in mineral and protein supplements did not affect the performance of grazing bull calves.

<p>The aurochs Bos primigenius, extinct since 1627, was the wild progenitor of cattle. It is believed that all European cattle originate from one domestication event in the Near East 10 000 years ago. However, it is evident from the archaeological record that the aurochs survived into historic time and spent many years existing alongside domestic cattle. Thus, a question posed is whether aurochsen were locally domesticated or incorporated into early domestic cattle stock.</p><p>In this thesis, genetic techniques are applied to ancient and modern DNA from bovids in order to study questions relating to the origin of early European cattle. DNA from ancient specimens is fragmented and in greatly reduced quantity. Therefore mitochondrial DNA, present in many copies in the living cell, has long been dominating the ancient DNA research field. Analyses of ancient DNA presented in this work are based on both mitochondrial DNA and nuclear DNA, through the study of Single Nuclear Polymorohism (SNPs). A method for typing ancient SNPs was developed and applied to ancient cattle bones.</p><p>Mitochondrial DNA of cattle is structured into five geographically distributed lineages, the dominant lineage in Europe is also found in the Near East where additional lineages are found. This pattern has been attributed to the proposed domestication event in the Near East from where cattle carrying the single lineage were brought to Europe. However, the results presented here show that cattle domestication was more complicated than previously suggested. SNP data from extant cattle and bones from cattle and aurochs point towards a hybridisation event. European cattle appear indeed to have been domesticated in the Near East and brought in to the European continent from there. However, once in Europe, hybridisation with local aurochsen took place. It appears therefore that today’s cattle descend both from both Anatolian and European aurochsen.</p>

Objectives were to: 1) Evaluate the effectiveness of presynchronization with GnRH before the CO‐Synch + CIDR protocol with timed AI (TAI) at 66 h in Bos indicus‐influenced cattle; 2) Characterize ovarian events associated with the presynchronization; 3) Evaluate the efficacy of measuring vaginal electrical resistance (VER) to assess follicular maturity at TAI; and 4) Compare serum concentrations of progesterone (P4) in ovariectomized cows bearing new or previously used CIDR devices with or without autoclaving. In Exp. 1 and 2, cattle received either GnRH or saline on day ‐7. The CO‐Synch + CIDR protocol included a CIDR insert and GnRH (GnRH‐1; day 0), removal of CIDR and PGF2α on day 7, and GnRH (GnRH‐2) and TAI 66 h after CIDR removal. In Exp. 1, pregnancy rate of females with BCS ≥ 5 tended to differ (P=0.085) between Presynch (38%) and CO‐Synch + CIDR (54%). In Exp. 2, ovulatory response to GnRH‐1 was greater (P<0.01) in the Presynchronization (58%) than in the CO‐Synch + CIDR (27.1%) group. Emergence of a follicular wave after GnRH‐1 and ovulation rate after GnRH‐2 did not differ between groups. More (P<0.01) females that developed a follicular wave after GnRH‐1 ovulated (82%) after GnRH‐2, compared to those that did not (29%). Mean VER (ohms) was greatest (101.4±0.8) on day 0 and declined (P<0.01) to 95.2±0.8 and 82±0.8, respectively, on days 7 and 10. We observed a low negative but significant relationship (r=0.38; P<0.001) between VER and follicular size on day 0, 7, and 10. VER difference (day 10 minus day 7) did not differ between females with small and large follicles at TAI. Mean concentrations of P4 during the 7‐day insertion period were greater (P<0.03) for new (3.7 ng/ml) and re‐used autoclaved (3.4 ng/ml) than for re‐used disinfected CIDRs (2.8 ng/ml). In summary, Presynch improved ovulation rate after GnRH‐1, but did not improve pregnancy rates compared to CO‐Synch + CIDR. Follicular maturity estimation was not feasible using VER as applied in this study. Autoclaving may be the best option when re‐using CIDR inserts because it creates greater concentrations of P4 during the first 48 h.

Objectives were to determine: 1) whether estradiol benzoate (EB) provides a superior alternative to GnRH for synchronizing emergence, growth and maturation of a new follicular wave for fixed timed AI (TAI) in Bos indicus-influenced cattle using CIDR-based protocols, 2) the effect of 48 h calf removal at CIDR removal on the rate of maturational synchrony of the dominant follicle and 3) the effect of varying the magnitude of peak plasma progesterone (P4) concentrations following CIDR insertion on the suppression of FSH and LH secretion in a CIDR-based protocol using EB. In experiment 1, sixty-four Braford (F-1) females were stratified by BCS, parity and days postpartum and assigned randomly to one of four groups in a 2 x 2 factorial arrangement of treatments: 1) Select-Synch + CIDR, 2) Select-Synch + CIDR with 48 h calf removal, 3) E-Synch + CIDR or 4) E-Synch + CIDR with 48 h calf removal. A greater number of cattle in the EB treated group exhibited NFWE compared to the GnRH group, 29 vs 17 cows for EB and GnRH respectively, (P<0.0006). Intervals to NFWE were also greater in EB treated cattle than in GnRH treated cattle, 4.2 vs 2.7 d for EB and GnRH treated cattle respectively, (P<0.0001). Proportions of GnRH- and EB-treated cows ovulating after CIDR removal did not differ. Post-CIDR suckling status did not affect ovulation frequency or interval to ovulation. In experiment 2, eight pubertal (F-1) heifers were used in a Latin Square design with four treatment levels of P4: 1) EB only, 2) EB and new CIDR, 3) EB and new autoclaved CIDR, 4) EB, new autoclaved CIDR and P4 injection at CIDR insertion. Treatments 2 through 4 increased (P < 0.01) mean plasma P4 concentrations compared to treatment 1, with treatment 4 creating the greatest increase in P4 with the longest duration. Suppression of plasma FSH was greatest in group 4 (P<0.08), with mean 60 h concentrations less than in all other groups. Mean concentrations of LH were lesser in group 4 than groups 1 and 2. Frequencies of occurrence of NFWE and ovulation and intervals to NFWE did not differ among treatments. Results indicate that the use of EB and CIDR to synchronize Brahman x Hereford females may provide better synchronization for TAI compared to GnRH and CIDR based protocols.

The aurochs Bos primigenius, extinct since 1627, was the wild progenitor of cattle. It is believed that all European cattle originate from one domestication event in the Near East 10 000 years ago. However, it is evident from the archaeological record that the aurochs survived into historic time and spent many years existing alongside domestic cattle. Thus, a question posed is whether aurochsen were locally domesticated or incorporated into early domestic cattle stock. In this thesis, genetic techniques are applied to ancient and modern DNA from bovids in order to study questions relating to the origin of early European cattle. DNA from ancient specimens is fragmented and in greatly reduced quantity. Therefore mitochondrial DNA, present in many copies in the living cell, has long been dominating the ancient DNA research field. Analyses of ancient DNA presented in this work are based on both mitochondrial DNA and nuclear DNA, through the study of Single Nuclear Polymorohism (SNPs). A method for typing ancient SNPs was developed and applied to ancient cattle bones. Mitochondrial DNA of cattle is structured into five geographically distributed lineages, the dominant lineage in Europe is also found in the Near East where additional lineages are found. This pattern has been attributed to the proposed domestication event in the Near East from where cattle carrying the single lineage were brought to Europe. However, the results presented here show that cattle domestication was more complicated than previously suggested. SNP data from extant cattle and bones from cattle and aurochs point towards a hybridisation event. European cattle appear indeed to have been domesticated in the Near East and brought in to the European continent from there. However, once in Europe, hybridisation with local aurochsen took place. It appears therefore that today’s cattle descend both from both Anatolian and European aurochsen.

Objectives were to determine: 1) whether estradiol benzoate (EB) provides a superior alternative to GnRH for synchronizing emergence, growth and maturation of a new follicular wave for fixed timed AI (TAI) in Bos indicus-influenced cattle using CIDR-based protocols, 2) the effect of 48 h calf removal at CIDR removal on the rate of maturational synchrony of the dominant follicle and 3) the effect of varying the magnitude of peak plasma progesterone (P4) concentrations following CIDR insertion on the suppression of FSH and LH secretion in a CIDR-based protocol using EB. In experiment 1, sixty-four Braford (F-1) females were stratified by BCS, parity and days postpartum and assigned randomly to one of four groups in a 2 x 2 factorial arrangement of treatments: 1) Select-Synch + CIDR, 2) Select-Synch + CIDR with 48 h calf removal, 3) E-Synch + CIDR or 4) E-Synch + CIDR with 48 h calf removal. A greater number of cattle in the EB treated group exhibited NFWE compared to the GnRH group, 29 vs 17 cows for EB and GnRH respectively, (P<0.0006). Intervals to NFWE were also greater in EB treated cattle than in GnRH treated cattle, 4.2 vs 2.7 d for EB and GnRH treated cattle respectively, (P<0.0001). Proportions of GnRH- and EB-treated cows ovulating after CIDR removal did not differ. Post-CIDR suckling status did not affect ovulation frequency or interval to ovulation. In experiment 2, eight pubertal (F-1) heifers were used in a Latin Square design with four treatment levels of P4: 1) EB only, 2) EB and new CIDR, 3) EB and new autoclaved CIDR, 4) EB, new autoclaved CIDR and P4 injection at CIDR insertion. Treatments 2 through 4 increased (P < 0.01) mean plasma P4 concentrations compared to treatment 1, with treatment 4 creating the greatest increase in P4 with the longest duration. Suppression of plasma FSH was greatest in group 4 (P<0.08), with mean 60 h concentrations less than in all other groups. Mean concentrations of LH were lesser in group 4 than groups 1 and 2. Frequencies of occurrence of NFWE and ovulation and intervals to NFWE did not differ among treatments. Results indicate that the use of EB and CIDR to synchronize Brahman x Hereford females may provide better synchronization for TAI compared to GnRH and CIDR based protocols.