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Our objective was to determine the effects of feeding 25-hydroxyvitamin D3 [25(OH)D3], or vitamin D3 (cholecalciferol) on plasma, mineral, and metabolite concentrations, mineral balance, mineral excretion, rumination, energy balance, and milk production of dairy cows. We hypothesized that supplementing 3 mg/d of 25(OH)D3 during the prepartum period would be more effective than supplementing vitamin D3 at the National Research Council (2001) levels to minimize calcium imbalance during the transition period and improve milk production of dairy cows. Forty multiparous, pregnant nonlactating-Holstein cows were enrolled in this study. Body weight, body condition score, parity, and milk yield in the previous lactation (mean ± standard deviation) were 661 ± 59.2, 3.46 ± 0.35, 1.79 ± 0.87, and 33.2 ± 6.43 kg/d, respectively. Cows were enrolled into the blocks (n = 20 for each treatment) at 30 d of the expected day of calving to receive an acidogenic diet (373 g/kg of neutral detergent fiber and 136 g/kg of crude protein, dry matter basis; -110 mEq/kg) associated with the treatments: (1) control (CTRL), vitamin D3 at 0.625 mg/d (equivalent to 25,000 IU of vitamin D3/d) or (2) 25(OH)D3 at 3 mg/d (equivalent to 120,000 IU of vitamin D3/d). All cows were fed with the base ration for 49 d after calving. Blood samples were taken on d 7, 0, 1, 2, 21, and 42, relative to calving. No effect of treatment was observed for prepartum dry matter intake or body condition score. A trend for increase of ionized Ca was observed for the cows fed 25(OH)D3, compared with the CTRL, but no effect of treatment was detected for total Ca or total P. Feeding 25(OH)D3 increased colostrum yield. The plasmatic concentration of 25-hydroxyvitamin D3 was increased with 25(OH)D3 supplementation. 25-Hydroxyvitamin D3 supplementation increased plasma glucose concentration at parturition. The postpartum dry matter intake was not influenced by treatments. Feeding 25(OH) D3 increases milk yield, 3.5% fat-corrected milk, and energy-corrected milk and improves milk yield components in early lactation. Overall, these findings suggest that 25(OH)D3 at 3 mg/d can improve the energy metabolism and lactation performance, compared with the current-feeding practice of supplementing vitamin D3 at 0.625 mg/d. Made available in DSpace on 2022-07-07T12:20:19Z (GMT). No. of bitstreams: 1 Effects-of-feeding-25-hydroxyvitamin-D3-with-an-acidogenic-diet.pdf: 810895 bytes, checksum: 6b70fe5ba2a4620281c061a6a0d712a1 (MD5) Previous issue date: 2022

Mastitis is the most common disease in dairy herds and the main cause of economic losses in milk production worldwide. This inflammatory reaction of the mammary gland affects the quantity, composition and quality of milk produced and its suitability for the dairy industry. Despite of its importance, Colombia has no regulations on somatic cell count (SCC); that is, no official upper limits have been established for the dairy industry. The current quality-based payment system for raw milk does not encourage local producers to reduce the level of somatic cells. Consequently, Colombia is at a disadvantage compared to countries that include this parameter in their payment schemes and subscribe to international free trade agreements, affecting the competitiveness of the Colombian dairy sector. This article reviews the types of somatic cells, the microbiology of mastitis, its etiology and diagnosis, the changes that generate the composition of milk, and the impact of high SCCs on the quality of dairy products, such as yogurt, cheese, and milk powder. The final section offers a reflection on the problem of high SCCs in Colombia and the lack of regulations in this regard. Resumen La mastitis es la enfermedad más frecuente en los hatos lecheros y es la principal causa de pérdidas económicas en la producción de leche alrededor del mundo. Esta reacción inflamatoria de la glándula mamaria afecta la cantidad, composición, calidad y aptitud de la leche para procesamiento por la industria. Sin embargo, en Colombia no existe normatividad sobre el recuento de células somáticas, principal indicador de mastitis; es decir, no existen límites oficiales que sirvan de referencia para la industria lechera. El sistema de pago basado en calidad no incentiva al productor a disminuir el nivel de células somáticas. Esto coloca al país en desventaja frente a otros países que exigen este parámetro en su esquema de pago y con los cuales Colombia tiene tratados de libre comercio, afectando negativamente la competitividad del sector lechero colombiano. En este artículo se hace una revisión sobre los tipos de células somáticas, la microbiología de la mastitis, su etiología, el diagnóstico, los cambios que generan la composición de la leche y el impacto que tienen los altos recuentos de células somáticas sobre la calidad de algunos derivados lácteos como yogures, quesos y leche en polvo. En la parte final se presenta una reflexión sobre la problemática de los altos recuentos de células somáticas en Colombia y la falta de normatividad al respecto. Resumo A mastite é a doença mais frequente nos rebanhos leiteiros e é a principal causa de perdas econômicas na produção de leite em todo o mundo. Essa reação inflamatória da glândula mamária causa efeitos na quantidade, composição, qualidade e aptidão de leite processado pela indústria. No entanto, na Colômbia, não há regulamentação sobre a contagem de células somáticas até o momento, o principal indicador de mastite, ou seja, não há limites oficiais que sejam referência para a indústria leiteira. O sistema de pagamento baseado na qualidade não incentiva o produtor a diminuir o nível de células somáticas. Isso coloca o país em desvantagem em comparação com outros países que exigem esse parâmetro em seu esquema de pagamento e com quem a Colômbia possui acordos de livre comércio, afetando negativamente a competitividade do setor. Este documento analisa os tipos de células somáticas, a microbiologia da mastite, sua etiologia, diagnóstico, alterações na composição do leite e o impacto da alta contagem de células somáticas na qualidade do leite. Alguns derivados de leite, como iogurtes, queijos e leite em pó. Na parte final, é feita uma reflexão sobre o problema da alta contagem de células somáticas na Colômbia e a falta de regulamentação nesse sentido.

This study evaluated the genetic diversity and antimicrobial susceptibility of Staphylococcus aureus isolates from dairy cows in Minas Gerais, Brazil. Thirty-seven isolates from five municipalities (8 herds) were genotyped using multi-locus sequence typing (MLST) and susceptibility to 12 antimicrobial agents was tested using the disk diffusion method. High resistance rates for penicillin [75.68% (28/37)], ampicillin [70.27% (26/37)], and tetracycline [70.27% (26/37)] were detected. Multidrug resistance was observed in seven [18.92% (7/37)] isolates, and two were suggestive of Methicillin-resistant Staphylococcus aureus (MRSA). Among the 37 isolates, 33 novel sequence types (ST) and two known STs (ST126 and ST746) were identified in MLST. The clonal complexes more frequently observed were: CC97 [78.38%; (29/37)], CC1 [8.11%; (3/37)] and CC5 [5.40%; (2/37)]. Minimum?spanning tree (MST) analysis according to data from municipalities, herds, and resistance patterns for all isolates did not show any clustering pattern. However, the MST comparing all Brazilian S. aureus isolates deposited in the PubMLST database and from this study depicted an association between the genotype and strain origin (clinical sample). Isolates from this study that belong to CC97 were close to database isolates from milk and dairy products, while those that belong to CC1 and CC5 were close to database isolates from human sources and the environment of dairy farms or industries. In conclusion, our results showed a high rate of resistance to penicillins and tetracyclines and great genetic diversity among the S. aureus isolates from bovine mastitis genotyped in the present study. RESUMO - Este estudo teve como objetivo avaliar a diversidade genética e a suscetibilidade a antimicrobianos de cepas de Staphylococcus aureus isoladas de vacas leiteiras em Minas Gerais, Brasil. Trinta e sete cepas provenientes de cinco municípios (oito rebanhos) foram genotipadas usando a técnica multi-locus sequence typing (MLST) e a suscetibilidade a 12 antimicrobianos foi avaliada pelo método de difusão em disco. Foram detectadas altas taxas de resistência para penicilina [75,68% (28/37)], ampicilina [70,27% (26/37)] e tetraciclina [70,27% (26/37)] entre os isolados. A multirresistência foi observada em sete [18,92% (7/37)] isolados e dois foram classificados como sugestivos de Staphylococcus aureus resistente à meticilina (MRSA). Entre os 37 isolados, 33 novos sequence types (ST) e dois STs conhecidos (ST126 e ST746) foram identificados pelo MLST. Os complexos clonais mais frequentemente observados foram: CC97 [78,38%; (29/37)], CC1 [8,11%; (3/37)] e CC5 [5,40%; (2/37)]. Foi construída uma minimum?spanning tree (MSTs) com todos isolados estudados e esta não mostrou padrão de agrupamento quando comparada com dados epidemiológicos como municípios e rebanho, do qual foi isolado, e perfis de resistência a antimicrobianos. Uma segunda MST foi construída comparando os isolados deste estudo e todas as cepas de S. aureus depositadas no banco de dados PubMLST provenientes do Brasil, que mostrou associação entre o genótipo, STs e a origem da cepa. Foi possível observar entre os isolados do estudo que, aqueles que pertenciam ao CC97, eram geneticamente mais próximos das cepas depositadas no PubMLST isoladas de leite e de produtos lácteos, enquanto aqueles que pertenciam aos CC1 e CC5 estavam mais próximos a cepas isoladas de humanos ou do ambiente de fazendas e indústrias de laticínios. Em conclusão, nossos resultados mostraram um alto índice de resistência às penicilinas e tetraciclinas e grande diversidade genética entre as cepas de S. aureus isoladas de casos de mastite bovina. Made available in DSpace on 2022-07-21T11:19:21Z (GMT). No. of bitstreams: 1 Genetic-diversity-and-antimicrobial-susceptibility-of-Staphylococcus-aureus.pdf: 1189969 bytes, checksum: 7d02b2551a4c2c2287f83cc00c8d4562 (MD5) Previous issue date: 2023

Background: The most common ocular disease affecting cattle worldwide is infectious bovine keratoconjunctivitis (IBK), which has been associated with Moraxella bovis bacterium. Objective: To report the molecular characterization of the ocular bacterial microbiota and its relation to IBK in cattle in two dairy regions in Michoacán, Mexico. Methods: A total population of 761 bovines were evaluated, of which 17 (2.23%) showed symptoms of IBK. Thirty-eight bacterial isolates from ocular samples of bovines with IBK were characterized by Gram-staining and antimicrobial sensitivity. In addition, isolates were identified by sequence comparisons of the 16S ribosomal gene. Results: The genus Moraxella was one of the most abundant bacteria and M. bovoculi was the most predominant species. Conclusion: The bacterial isolates identified in eye lesions of cattle and associated to IBK are diverse. To the author´s knowledge, this is the first study on the subject in Mexico; therefore, more research is needed to estimate the incidence of IBK and determine its associated microbiota. Resumen Antecedentes: la enfermedad ocular más común que afecta al ganado en todo el mundo es la queratoconjuntivitis infecciosa bovina (IBK), que se ha asociado con la bacteria Moraxella bovis. Objetivo: reportar la caracterización molecular de la microbiota bacteriana ocular y su relación con IBK en ganado de dos regiones lecheras en Michoacán, México. Métodos: se evaluó una población total de 761 bovinos de los cuales 17 (2,23%) mostraron síntomas de IBK. Se obtuvieron treinta y ocho aislamientos bacterianos de muestras oculares de bovinos con IBK, los cuales se caracterizaron por tinción de Gram y sensibilidad antimicrobiana. Además, los aislamientos se identificaron mediante comparaciones de secuencias del gen ribosomal 16S. Resultados: el género Moraxella fue una de las bacterias más abundantes y M. bovoculi fue la especie más predominante. Conclusión: los aislamientos bacterianos identificados en lesiones oculares de bovinos y asociados a IBK son diversos. Hasta donde sabemos, este es el primer estudio sobre el tema realizado en México; por lo tanto, es necesario ampliar esta investigación para estimar la incidencia de IBK y determinar la microbiota asociada con la misma. Resumo Antecedentes: a doença ocular mais comum que afeta o gado no mundo é a ceratoconjuntivite bovina (IBK), que tem sido associada à bactéria Moraxella bovis. Objetivo: relatar a caracterização molecular da microbiota bacteriana ocular e sua relação com a IBK em bovinos de duas regiões leiteiras de Michoacán, México. Métodos: foi avaliada uma população total de 761 bovinos, más apenas 17 (2,23%) apresentaram sintomas de IBK. Trinta e oito isolados bacterianos de amostras de olho bovino com IBK foram caracterizados por coloração de Gram e sensibilidade antimicrobiana. Além disso, os isolados foram identificados por comparação de sequências do gene ribossômico 16S. Resultados: a microbiota bacteriana associada à IBK foi diversa, sendo o gênero Moraxella uma das mais abundantes e M. bovoculi a espécie predominante. Conclusão: de acordo com o conhecimento dos autores, este é o primeiro estudo sobre o tema no México até o momento, portanto é necessário expandir essa pesquisa para estimar a incidência de IBK e determinar a microbiota associada à mesma.

Staphylococcus is one of the most frequent etiological agents of bovine mastitis, causing economic losses to milk farming. This study aimed to describe the milk production and management practices in 15 herds located in three microregions of the State of Rondônia and to identify the antimicrobial resistance profile of 97 isolates of the genus Staphylococcus from these herds. The isolates were subjected to antimicrobial susceptibility tests using the agar diffusion method. Twenty-nine S. aureus isolates were selected to determine their minimum inhibitory concentration (MIC). In the farms studied, the breeding system was semi-intensive, with the Girolando breed being predominant. Milking was performed predominantly using a mechanical milking system (86.7%), twice a day (66.7%), in the presence of the calf (53.8%). The average number of lactating cows in the farms was 24, with an average milk production of 204.9 L d-1 and a milk productivity of 10.2 L animal-1 d-1. The use of antimicrobials for the treatment and prevention of bovine mastitis was reported for all properties, and therapy for dry cows was adopted in 80% of the herds. The percent susceptibility to antimicrobials ranged from 85.5% to 100% for S. aureus, 22.2% to 88.9% for coagulase-positive staphylococci (CPS), and 69.2% to 100% for coagulase-negative staphylococci (CNS), with the highest resistance frequencies for penicillin, ampicillin, and tetracycline. Among the S. aureus isolates, 100% susceptibility to oxacillin, cefalexin, and gentamicin was observed, and among the CNS isolates, 100% susceptibility to gentamicin was observed. None of the antimicrobials tested showed 100% in vitro effectiveness for CPS. CPS and CNS presented lower percentages of susceptibility to penicillin, ampicillin, and tetracycline than the S. aureus isolates. Twelve resistance patterns were detected, six of which were multiresistance patterns. The most prevalent resistance patterns were penicillin and ampicillin (PEN-AMP) and penicillin, ampicillin, and tetracycline (PEN-AMP-TET). Results of the MIC assay revealed that all 29 S. aureus isolates were susceptible to cephalothin, cefoxitin, tetracycline, and erythromycin, whereas 25 (86.2%) were susceptible to penicillin. RESUMO - O gênero Staphylococcus destaca-se como um dos agentes etiológicos mais frequentes da mastite bovina, causando prejuízos econômicos à pecuária de leite. Este estudo teve o objetivo de descrever a produção de leite e práticas de manejo de 15 rebanhos localizados em três microrregiões do Estado de Rondônia, e identificar o perfil de resistência aos antimicrobianos de 97 isolados do gênero Staphylococcus provenientes destes rebanhos. Os isolados foram submetidos a testes de suscetibilidade a antimicrobianos, utilizandose a técnica de difusão em ágar. Foram selecionados 29 isolados de Staphylococcus aureus (S. aureus) para determinação da concentração inibitória mínima (CIM). Nas propriedades estudadas, o sistema de criação era semi-intensivo, com predomínio da raça Girolando. A ordenha era realizada predominantemente em sistema de ordenha mecânica (86,7%), duas vezes ao dia (66,7%) e com a presença do bezerro (53,8%). A média do número de vacas em lactação das propriedades era de 24 animais, com média de produção de leite de 204,9 L d-1 e produtividade de leite de 10,2 L animal-1 d-1. O uso de antimicrobianos para o tratamento e prevenção da mastite bovina foi relatado em todas as propriedades, sendo adotada a terapia da vaca seca em 80% dos rebanhos. A percentagem de susceptibilidade aos antimicrobianos variou de 85,5 a 100% para S. aureus, 22,2 a 88,9% para Staphylococcus coagulase positivos (SCP) e 69,2 a 100% para Staphylococcus coagulase negativos (SCN), sendo as maiores frequências de resistência para penicilina, ampicilina e tetraciclina. Entre os isolados de S. aureus foi observada 100% de susceptibilidade aos antimicrobianos oxacilina, cefalexina e gentamicina, e entre os isolados de SCN, 100% de susceptibilidade à gentamicina. Nenhum dos antimicrobianos testados apresentou 100% de efetividade in vitro para SCP. SCP e SCN apresentaram menores percentagens de susceptibilidade à penicilina, ampicilina e tetraciclina do que os isolados de S. aureus. Foram observados 12 padrões de resistência, sendo seis padrões de multirresistência. Os padrões de resistência mais prevalentes foram resistência à penicilina e ampicilina (PEN-AMP) e à penicilina, ampicilina e tetraciclina (PEN-AMP-TET). A determinação da CIM dos 29 isolados de S. aureus mostraram que todos foram susceptíveis à cefalotina, cefoxitina, tetraciclina e eritromicina, e 25 (86,2%) foram susceptíveis à penicilina. Made available in DSpace on 2022-05-03T21:12:27Z (GMT). No. of bitstreams: 1 Antimicrobial-resistance.pdf: 228790 bytes, checksum: 6a53e48a68cd5fd21a1f6b4ab4dd8e0d (MD5) Previous issue date: 2022 Short communications.

As tecnologias de reprodução artificial, como a produção de oócitos e embriões, desempenham um papel importante na disseminação de material genético superior, contribuindo de forma efetiva para acelerar o ganho genético de características de interesse comercial no sistema de produção e no desenvolvimento da cadeia produtiva de carne e leite. Frente a isso, o objetivo deste estudo foi avaliar diferentes metodologias na avaliação genética da produção de embriões e oócitos em bovinos Gir Leiteiro e identificar as estratégias mais adequadas para futuras avaliações genéticas da raça. No primeiro capítulo, apresentamos a revisão de literatura sobre os temas que estão diretamente relacionamentos aos objetivos do nosso projeto. No segundo capítulo, utilizamos modelos de repetibilidade e regressão aleatória (RRM) para estimar parâmetros genéticos e predizer valores genéticos para a produção de oócitos e embriões, e identificamos os modelos que resultaram em maiores ganhos genéticos na produção de oócitos e embriões. No terceiro capítulo, investigamos o impacto do estresse térmico nos parâmetros genéticos e valores genéticos para produção de oócitos e embriões em animais da raça Gir Leiteiro. E, no quarto capítulo, avaliamos a eficiência dos modelos com distribuição Gaussiana (variável não transformada — LIN; transformada por logaritmo — LOG; transformada pelas distribuições de Anscombe — ANS) e Poisson (POI) na avaliação genética para a produção de oócitos e embriões. A herdabilidade estimada pelo RRM foi superior à estimada pelo modelo de repetibilidade, e o ganho genético foi maior, com acréscimos variando entre 0,02 (13,33%) e 0,26 (152,94%) ao utilizar o RRM. Observamos uma reordenação na classificação dos valores genéticos preditos dos 5% melhores touros e fêmeas ao longo da idade da doadora no momento da coleta de óocitos. É recomendável considerar o efeito do estresse térmico por meio dos índices de temperatura e umidade nas avaliações genéticas da raça para produção de oócitos e embriões e, assim, é possível selecionar animais tolerantes ao estresse térmico em características relacionadas à reprodução artificial. Também observamos o reordenamento dos melhores animais em relação às escalas de idades para coleta de oócitos e do índice de temperatura e umidade. Dessa forma, esses fatores devem ser levados em consideração no momento de identificar e selecionar os candidatos à reprodução. Ainda, identificamos que o modelo POI ajustou-se melhor aos dados e resultou em maior acurácia dos valores genéticos quando comparado aos demais modelos com distribuição de probabilidade Gaussiana (LIN, LOG e ANS). Os resultados obtidos nesta tese suportam a conclusão de que é possível obter progresso genético para a produção de oócitos e embriões por meio de seleção. Isso pode contribuir para o crescimento econômico de fazendas e demais empresas envolvidas na comercialização de embriões. Além disso, a rápida disseminação de material genético superior, proporcionada pelas técnicas reprodutivas via grande número de progênies de fêmeas com alto valor genético para diferentes características de interesse econômico, favorecem também o desenvolvimento e o retorno financeiro para os sistemas produtivos. Artificial reproduction technologies, such as the production of oocytes and embryos, play an important role in the dissemination of superior genetic material, effectively contributing to accelerate the genetic gain of traits of commercial interest in the production system and in the development of the production chain of meat and milk. In view of this, the objective of this study was to evaluate different methodologies in the genetic evaluation of the production of oocytes and embryos in Dairy Gir cattle and to identify the most appropriate strategies for future genetic evaluations of the breed. In the first chapter, we present a literature review on topics that are directly related to the objectives of our project. In the second chapter, we used repeatability and random regression (RRM) models to estimate genetic parameters and predict breeding values for oocyte and embryo production, and we identified the models that resulted in the greatest genetic gains in oocyte and embryo production. In the third chapter, we investigated the impact of heat stress on genetic parameters and breeding values for the production of oocytes and embryos in Dairy Gir animals. And, in the fourth chapter, we evaluated the efficiency of models with Gaussian distribution (non-transformed variable — LIN; transformed by logarithm — LOG; transformed by the Anscombe distributions — ANS) and Poisson (POI) in the genetic evaluation for the production of oocytes and embryos. The heritability estimated by the RRM was higher than that estimated by the repeatability model, and the genetic gain was greater, with increases ranging between 0.02 (13.33%) and 0.26 (152.94%) when using the RRM. We observed a reordering in the classification of the predicted breeding values of the top 5% sires and females along the age of the donor at ovum pick-up. It is recommended to consider the effect of heat stress through the temperature-humidity index in the genetic evaluations of the breed for the production of oocytes and embryos and, thus, it is possible to select animals tolerant to heat stress in traits related to artificial reproduction. We also observed the reordering of the best animals in relation to the age scales for age at ovum pick-up and the temperature-humidity index. Thus, these factors must be taken into account when identifying and selecting breeding candidates. Furthermore, we identified that the POI model fitted the data better and resulted in greater accuracy of the breeding values when compared to the other models with Gaussian probability distribution (LIN, LOG and ANS). The results obtained in this thesis support the conclusion that it is possible to obtain genetic progress for the production of oocytes and embryos through selection. This can contribute to the economic growth of farms and other companies involved in the commercialization of embryos. In addition, the rapid dissemination of superior genetic material, provided by reproductive techniques via a large number of progenies of females with high genetic value for different traits of economic interest, also favors the development and financial return for production systems.

The livestock performance in tropical regions has been limited by environmental conditions that causes heat stress and favors the development of parasites and diseases, impairing animal health. Heat stress disturbs animal homeostasis and afects animal production and fertility, with negative impacts on meat and milk quality. Flies and ticks proliferate easily under hot-humid weather, which makes difcult the control of their population, resulting in an increased parasitism. Tropical pastures usually have high dry matter production, but it is challenging to keep high production and quality under diferent environmental conditions throughout the year, constraining animal performance. Several strategies have been adopted in an attempt to overcome such hurdles in the tropical regions, but defnitive solutions are yet to be implemented. In the last 20 years, biotechnologies, such as in vitro embryo production and genomic selection, have played an important role on cattle production in tropical countries. Genome editing (GnEd) is the novel tool in the toolbox for cattle production. GnEd with genomic selection ofers the opportunity to boost the genetic gain in breeding programs of tropical cattle in fewer generations. It can be applied for disease resistance, to control parasite population, and to improve pasture quality and tolerance to biotic and abiotic stresses, favoring animal health and nutrition. Moreover, there is a perspective for the use of GnEd to control cattle methane emission by editing genes of methanogens present in the rumen. Although GnEd can already be applied to improve some traits, studies are still required for the identifcation of candidate genes in animals, tropical pastures, parasites, and microorganisms that can be targeted by gene editing in order to ofer a robust contribution to the improvement of cattle production in the hot regions. Some examples of the use of GnEd are presented in this review, focusing on new perspectives of using GnEd to increase cattle production under the challenges of the tropical environments. Made available in DSpace on 2022-03-22T13:00:21Z (GMT). No. of bitstreams: 1 Genome-editing.pdf: 3034362 bytes, checksum: 710e9d57d3d55119b9a76cef0de78148 (MD5) Previous issue date: 2022

Cattle are susceptible to chronic leptospirosis infection, that results in reduced milk production and reproductive disorders such as abortions, stillbirths, fetal malformation, and mummified fetuses, causing significant economic losses. Commercially available vaccines against leptospirosis offer limited protection to cattle because they contain only the most prevalent serovars worldwide, even though they are not prevalent in the specific region. This study aimed to evaluate the prevalence of specific antibodies against Leptospira serogroups, reproductive disorders and the risk factors in dairy herds from different mesoregions of Rio Grande do Sul State, Southern Brazil. Made available in DSpace on 2022-06-01T11:20:19Z (GMT). No. of bitstreams: 1 Leptospirosis-in-dairy-cattle.pdf: 933544 bytes, checksum: 6efe55c1a36bff2cea7ab926dd7f0b65 (MD5) Previous issue date: 2022

The objective of this work was to compare the main linear and nonlinear models used to describe lactation curves and to evaluate the nonlinearity of the nonlinear models, in order to obtain the most adequate model to describe the lactation curves of the Girolando breed. Data from 165 lactations of 89 3/4 Holstein + 1/4 Gyr cows were used, and average yield was calculated every 20 days up to 310 days of lactation. Seventeen models of lactation curves available in the literature were compared. The selection of the best model was based on the curvature measures of Bates & Watts, the bias of Box, adjusted coefficient of determination, Akaike’s information criterion, and residual standard deviation. The linear model of Cobuci estimated a yield peak of 16.7 kg at 40 days of lactation, whereas the nonlinear model of Wood estimated a yield peak of 16.8 kg at 41 days of lactation and a persistence of 6.82. Nonlinearity measures were the most appropriate for selecting the most suitable nonlinear model for the description of lactation curves. To describe the lactation curves of the Girolando breed, the most suitable linear model is that of Cobuci and the nonlinear model is that of Wood. Resumo O objetivo deste trabalho foi comparar os principais modelos lineares e não lineares usados para descrever curvas de lactação e avaliar a não linearidade dos modelos não lineares, para obter o modelo mais adequado para a descrição das curvas de lactação da raça Girolando. Foram utilizados dados de 165 lactações de 89 vacas 3/4 Holandesas + 1/4 Gir, tendo-se calculado a produção média a cada 20 dias até 310 dias de lactação. Foram comparados 17 modelos de curvas de lactação disponíveis na literatura. A seleção do melhor modelo foi feita com base nas medidas de curvatura de Bates & Watts, no vício de Box, no coeficiente de determinação ajustado, no critério de informação de Akaike e no desvio-padrão residual. O modelo linear de Cobuci estimou um pico de produção de 16,7 kg aos 40 dias de lactação, enquanto o modelo não linear de Wood estimou um pico de produção de 16,8 kg aos 41 dias de lactação e persistência de 6,82. As medidas de não linearidade foram as mais adequadas para selecionar o modelo não linear mais adequado para a descrição das curvas de lactação. Para descrever as curvas de lactação da raça Girolando, o modelo linear mais adequado é o de Cobuci e o não linear é o de Wood.

This study evaluated the effect of crude protein (CP) reduction in four diets (156, 139, 132, and 127 g Kg-1 DM) maintaining constant metabolizable protein (188 g/day) on the follicular fluid and cumulus-oocyte complexes of mid-lactating Girolando cows. Twenty-two Girolando cows with average of 21.55 ±3.19 L daily milk yield, 105.30 ±22.62 days in lactation and 3.22 ±0.03 body condition score were selected. To reduce CP in diets and maintain constant metabolizable protein, urea and soybean meal were gradually replaced by lignosulfonate-treated soybean meal (SoyPass®, Cargill), resulting in an increase in rumenundegradable protein and a reduction in rumen degradable protein. A linear and quadratic reduction was observed in the plasma and follicular fluid urea nitrogen concentration following CP reduction, with the most intense reduction occurring in the 127 g Kg-1 DM group (p

Resumo: A pecuária de corte em Mato Grosso é referência nacional, destacando-se entre outros fatores pelo tamanho de seu rebanho. Todavia sua pecuária leiteira vem perdendo participação no cenário doméstico. Invariavelmente, a atividade de corte e leite tem relação intrínseca no estado, onde os ciclos da pecuária de corte são fatores determinantes para explicar a produção e o preço do leite. Isso é observado na presença de uma relação de curto prazo mais intensa entre a produção de leite com seu preço, como esperado, mas também com o preço do bezerro e com o da @ do boi gordo. O efeito da resposta ao impulso na produção de leite mostra que a variável que mais impacta na decisão do produtor em relação à produção de leite é o preço da @ do boi. Choques no preço da @ produzem uma resposta negativa na produção de leite, mas o efeito do preço do bezerro por sua vez, influencia positivamente a produção. A falta de genética especializada pode ser uma das principais causas dessa estreita relação, fazendo com que mudanças no mercado de carne bovina do estado e na produção de carne afetem significativamente a produção e o preço do leite. | Abstract: Livestock in Mato Grosso can be considered a national reference, standing out among other factors due to its herd size. However, dairy farming has been losing participation in the domestic scenario. Invariably, beef and milk production have an intrinsic relationship in the state, where beef livestock cycles determine factors to explain the production and price of milk. That is observed in the presence of an intense short-term relationship between milk production and price, as expected, and the calf price and live cattle. The effect of the impulse response on milk production shows that the variable that most impacts the producer's decision concerning milk production are the price of live cattle. Shocks in the price of live cattle produce a negative response in milk production, but the effect of the calf's price in turn positively influences production. The lack of specialized genetics may be one of the main causes of this close relationship, causing changes in the state's beef market and meat production to significantly affect milk production and price. Made available in DSpace on 2022-08-04T16:19:21Z (GMT). No. of bitstreams: 1 2022-cpamt-lbl-analise-co-integracao-pecuaria-leite-corte-mato-grosso.pdf: 931004 bytes, checksum: a79bd3c1fbcb6866799332bef017bc50 (MD5) Previous issue date: 2022

Body condition score (BCS) is a categorical variable that is widely accepted as an important tool for subjectively quantifying energy reserves in dairy cows. The aims of this study was to compare milk production and some metabolic parameters of crossbred dairy cows with low, adequate and high BCS in the recent postpartum period (PPP). This study included lactation data from 35 crossbred Girolando (Holstein × Gir) cows from calving to 90 days in milk. Cows were evaluated every 15 days for BCS, milk production, live weight, internal angle of the rump (IAR) and serum concentration of ?-hydroxybutyrate (ßHB). BCS loss and nadir of the BCS in PPP were also evaluated. Cows were divided into 3 groups, as follows: High, Adequate and Low BCS, according to the BCS recommendation for cows with less than 100 days in lactation. Cows with Adequate BCS had higher milk production than cows with High BCS (P = 0.01). Cows with High BCS had the highest (P < 0.001) live weight, BCS and IAR among the groups. In addition, these cows had a higher serum ßHB concentration than cows with Adequate BCS (P = 0.001) and had the greatest loss of BCS (P < 0.001) in the PPP. The results of this study showed that Girolando dairy cows with Adequate BCS at calving had higher milk production and better metabolic condition than cows with High BCS at calving. O escore de condição corporal (ECC) é uma variável categórica amplamente aceita como uma importante ferramenta para quantificar subjetivamente as reservas energéticas em vacas leiteiras. O objetivo deste estudo foi comparar a produção de leite e alguns parâmetros metabólicos de vacas leiteiras mestiças com baixo, adequado e alto ECC no período pós-parto (PPP) recente. Este estudo incluiu dados de lactação de 35 vacas mestiças Girolando (Holandês × Gir) do parto aos 90 dias de lactação. As vacas foram avaliadas a cada 15 dias quanto ao ECC, a produção de leite, o peso vivo, o ângulo interno da garupa (AIG) e a concentração sérica de ?-hidroxibutirato (ßHB). Também foram avaliados a perda de ECC e o nadir do ECC no PPP. As vacas foram divididas em 3 grupos, Alto, Adequado e Baixo ECC, de acordo com a recomendação de ECC para vacas com menos de 100 dias em lactação. Vacas com ECC adequado apresentaram maior produção de leite que vacas com ECC alto (P = 0,01). Vacas com alto ECC apresentaram o maior (P < 0,001) peso vivo, ECC e o AIG entre os grupos. Além disso, essas vacas apresentaram maior concentração sérica de ßHB do que vacas com ECC Adequado (P = 0,001) e apresentaram a maior perda de ECC (P < 0,001). Os resultados deste estudo demonstraram que vacas Girolando com ECC adequado ao parto apresentaram maior produção de leite e melhor condição metabólica em relação às vacas com alto ECC ao parto. La condición corporal (CC) es una variable categórica ampliamente aceptada como una herramienta importante para cuantificar subjetivamente las reservas de energía en las vacas lecheras. El objetivo de este estudio fue comparar la producción de leche y algunos parámetros metabólicos de vacas lecheras mestizas con CC baja, adecuada y alta en el posparto reciente (PP). Este estudio incluyó datos de lactancia de 35 vacas Girolando (Holstein × Gir) desde el parto hasta los 90 días de lactancia. Las vacas fueron evaluadas cada 15 días para CC, producción de leche, peso vivo, ángulo interno de la grupa (AIG) y concentración sérica de ?-hidroxibutirato (ßHB). También se evaluaron la pérdida de CC y el nadir de CC en PP. Las vacas se dividieron en 3 grupos, CC Alta, Adecuada y Baja, de acuerdo con la recomendación de CC para vacas con menos de 100 días de lactancia. Las vacas con CC adecuado tuvieron mayor producción de leche que las vacas con CC alto (P = 0,01). Las vacas con alto CC tuvieron el peso vivo, CC y AGA más altos (P < 0,001) entre los grupos. Además, estas vacas tenían una concentración sérica de ßHB más alta que las vacas con CC Adecuado (P = 0,001) y tenían la mayor pérdida de CC (P < 0,001). Los resultados de este estudio mostraron que las vacas Girolando con CC adecuado al parto tuvieron una mayor producción de leche y una mejor condición metabólica en comparación con las vacas con CC alto al parto. Made available in DSpace on 2022-06-02T18:19:24Z (GMT). No. of bitstreams: 1 cpafro-18764.pdf: 154137 bytes, checksum: a7d1e21b8ac29643a47a4d85ba61f440 (MD5) Previous issue date: 2022

Objective: The aim of this study was to estimate genetic parameters for 305-day cumulative milk yield and components, growth, and reproductive traits in Guzerá cattle. Methods: The evaluated traits were 305-day first-lactation cumulative yields (kg) of milk (MY305), fat (FY305), protein (PY305), lactose (LY305), and total solids (SY305); age at first calving (AFC) in days; adjusted scrotal perimeter (cm) at the ages of 365 (SP365) and 450 (SP450) days; and adjusted body weight (kg) at the ages of 210 (W210), 365 (W365) and 450 (W450) days. The (co)variance components were estimated using the restricted maximum likelihood method for single-trait, bi-trait and tri-trait analyses. Contemporary groups and additive genetic effects were included in the general mixed model. Maternal genetic and permanent environmental effects were also included for W210. Results: The direct heritability estimates ranged from 0.16 (W210) to 0.32 (MY305). The maternal heritability estimate for W210 was 0.03. Genetic correlation estimates among milk production traits and growth traits ranged from 0.92 to 0.99 and from 0.92 to 0.99, respectively. For milk production and growth traits, the genetic correlations ranged from 0.33 to 0.56. The genetic correlations among AFC and all other traits were negative ( 0.43 to 0.27). Scrotal perimeter traits and body weights showed genetic correlations ranging from 0.41 to 0.46, and scrotal perimeter and milk production traits showed genetic correlations ranging from 0.11 to 0.30. The phenotypic correlations were similar in direction (same sign) and lower than the corresponding genetic correlations. Conclusion: These results suggest the viability and potential of joint selection for dairy and beef traits in Guzerá cattle, taking into account reproductive traits. Made available in DSpace on 2022-07-12T10:19:22Z (GMT). No. of bitstreams: 1 Genetic-study-of-quantitative-traits-supports-the-use-of-Guzera.pdf: 565236 bytes, checksum: dfaa8a1ebf81c017549a592d9e4ae054 (MD5) Previous issue date: 2022

Research on genes affecting phenotypic variation in milk production and composition from indicine (Bos indicus) cattle is imperative, since these breeds are important tropical genetic resources, and there have been few studies investigating the genetic basis of these traits. We identified polymorphisms in k-casein (CSN3), b-lactoglobulin (LGB), thyroglobulin (TG) and prolactin (PRL) and examined their effect on milk and composition traits in the Guzerá breed. DNA samples of 260 Guzerá cattle selected for dual purpose use were genotyped. Allele frequencies observed for the A allele were 0.83, 0.18 and 0.25 respectively for CSN3, LGB and PRL genes, while for the TG gene T allele had an allele frequency of 0.09. For all polymorphisms evaluated, observed genotypic frequencies were in agreement with those expected according to the Hardy-Weinberg Equilibrium hypothesis. A polymorphism association study evaluated breeding values (BV) for 305-day milk (BV-M), fat (BV-F), and protein (BV-P) production, employing the allele substitution model using a sample of 139 cows belonged to 27 full and half-sib families of a MOET (multiple ovulation and embryo transfer) selection nucleus. Association was found between the LGB polymorphism and BV-M, BV-F and BV-P. Animals with LGB AA genotype have, on average, higher BV when compared to animals with LGB AB and BB genotypes (277.85 kg for BV-M, 12.09 kg for BV-F and 9.33 kg for BV-P). These findings contribute to a better understanding on the influence of these polymorphisms on milk production traits in Guzerá cattle. Made available in DSpace on 2022-08-25T17:20:01Z (GMT). No. of bitstreams: 1 Polymorphisms-in-genes-coding-milk-proteins-and-protein-hormones.pdf: 773850 bytes, checksum: 7276f37bf01b3e47be7ff66f1064736f (MD5) Previous issue date: 2022

Dairy farming is an important aspect of the Brazilian agricultural sector. The presence of numerous producers has created a large number of jobs in this field, contributing significantly to the rural economy. Artificial insemination (AI), used as one of the main means of reproduction, is increasingly gaining importance in the genetic improvement of animals. Given this scenario, the semen of bulls has become extremely marketable and an important aspect of the animal industry. This study aims to develop a hedonic model for the price of semen doses of dairy bulls based on the information from the main sellers of the product in the Brazilian market. The main findings reveal that there is an additional premium for proven bulls. Semen doses from Gir bulls proved to be more expensive, and the AI firm ALTA has a discount compared to the other firms. From the characteristics obtained in the tests, there is a premium only for the Predicted Transmitting Ability?Milk (volume). The most valued feature found is the dose being sexed, that is, the dose that guarantees the gestation of a female from its use. Semen doses from dead bulls has proved to be more expensive. Made available in DSpace on 2022-05-03T18:12:52Z (GMT). No. of bitstreams: 1 Hedonic-pricing.pdf: 611719 bytes, checksum: 4604b461eda6eb478ee7e079d99cfa53 (MD5) Previous issue date: 2022

The contribution of greenhouse gas (GHG) emissions from ruminant production systems varies between countries and between regions within individual countries. The appropriate quantification of GHG emissions, specifically methane (CH4), has raised questions about the correct reporting of GHG inventories and, perhaps more importantly, how best to mitigate CH4 emissions. This review documents existing methods and methodologies to measure and estimate CH4 emissions from ruminant animals and the manure produced therein over various scales and conditions. Measurements of CH4 have frequently been conducted in research settings using classical methodologies developed for bioenergetic purposes, such as gas exchange techniques (respiration chambers, headboxes). While very precise, these techniques are limited to research settings as they are expensive, labor-intensive, and applicable only to a few animals. Head-stalls, such as the GreenFeed system, have been used to measure expired CH4 for individual animals housed alone or in groups in confinement or grazing. This technique requires frequent animal visitation over the diurnal measurement period and an adequate number of collection days. The tracer gas technique can be used to measure CH4 from individual animals housed outdoors, as there is a need to ensure low background concentrations. Micrometeorological techniques (e.g., open-path lasers) can measure CH4 emissions over larger areas and many animals, but limitations exist, including the need to measure over more extended periods. Measurement of CH4 emissions from manure depends on the type of storage, animal housing, CH4 concentration inside and outside the boundaries of the area of interest, and ventilation rate, which is likely the variable that contributes the greatest to measurement uncertainty. For large-scale areas, aircraft, drones, and satellites have been used in association with the tracer flux method, inverse modeling, imagery, and LiDAR (Light Detection and Ranging), but research is lagging in validating these methods. Bottom-up approaches to estimating CH4 emissions rely on empirical or mechanistic modeling to quantify the contribution of individual sources (enteric and manure). In contrast, top-down approaches estimate the amount of CH4 in the atmosphere using spatial and temporal models to account for transportation from an emitter to an observation point. While these two estimation approaches rarely agree, they help identify knowledge gaps and research requirements in practice., Journal of Animal Science, 100 (7), ISSN:1525-3163, ISSN:0021-8812

This study determined whether adding an immunological homeopathic product (Imunorgan®) to the calf diet during the first months of life improves immune reactions, antioxidant responses, metabolism, and growth. The 12 calves with an average of 36±4 kg and 30 days of life, were divided into a control (n=6) and treatment (n=6) group who received the homeopathic product in milk during the first 30 days and subsequently in the concentrate (providing 10 g/day of the immunological homeopathic, based on Arsenicum album, Baptisia tinctoria, Calcarea carbonica, Iodum purum, Medicago sativa, Mercurius solubilis, Nux vomica, Pyrogenium, and sucrose vehicle). The animals in the treatment group had more significant body weight gain from 1 to 30 days of the experiment (p≤0.05). There was a treatment effect on hematologic results, with hemoglobin concentration showing major treatment x day interaction on day 90 (p≤0.05). Leukocyte, neutrophil, and lymphocyte counts were higher in the treatment group (p≤0.05). The albumin concentration in the treatment group animals was lower than in the control group (p≤0.05). The globulin concentration was higher in the treatment group (p≤0.05). There was a treatment x day interaction for the concentration of protein thiols on days 30, 60, and 90, with higher serum levels in calves in the treatment group (p≤0.05). Serum levels of reactive oxygen species were lower in calves of the treatment group (p≤0.05). The animals of the treated group showed a higher concentration of IgA. During the experiment, levels of ceruloplasmin, haptoglobin, transferrin, acid glycoprotein, and light-chain IgG also changed (treatment x day interaction). These findings suggest that the homeopathic product stimulated immunological responses. Este estudio determinó si agregar un agente homeopático inmunológico (Imunorgan®) a la dieta de los terneros durante los primeros meses de vida mejora las reacciones inmunológicas, las respuestas antioxidantes, el metabolismo y el crecimiento. Los 12 terneros, con un promedio de 36 kg y 30 días de vida, se dividieron en grupo control (n=6) y tratamiento (n=6) quienes recibieron el producto homeopático en leche durante los primeros 30 días y posteriormente en el concentrado (aportando 10 g/día del homeopático inmunológico, a base de sobre Arsenicum album, Baptisia tinctoria, Calcarea carbonica, Iodum purum, Medicago sativa, Mercurius solubilis, Nux vomica, Pyrogenium y vehículo de sacarosa). Los animales en el grupo de tratamiento tuvieron una ganancia de peso corporal más significativa de 1 a 30 días del experimento (p≤0.05). Hubo un efecto del tratamiento sobre los resultados hematológicos, mostrando la concentración de hemoglobina más grande interacción tratamiento x día en el día 90 (p≤0.05). Los recuentos de leucocitos, neutrófilos y linfocitos fueron mayores en el grupo de tratamiento (p≤0,05). La concentración de albúmina en los animales del grupo tratamiento fue menor que en el grupo control (p≤0.05). La concentración de globulina fue mayor en el grupo de tratamiento (p≤0.05). Hubo interacción tratamiento x día para la concentración de tioles proteicos en los días 30, 60 y 90, con niveles séricos más altos en los terneros del grupo de tratamiento (p≤0.05). Los niveles séricos de especies reactivas de oxígeno fueron menores en los terneros del grupo de tratamiento (p≤0.05). Los animales del grupo tratado mostraron una mayor concentración de IgA. Durante el experimento, los niveles de ceruloplasmina, haptoglobina, transferrina, glicoproteína ácida e IgG de cadena ligera también cambiaron (interacción tratamiento x día). Estos hallazgos sugieren que el agente homeopático estimuló las respuestas inmunológicas. Este estudo determinou se a adição de um agente homeopático imunológico (Imunorgan®) à dieta de bezerros durante os primeiros meses de vida melhora as reações imunológicas, respostas antioxidantes, metabolismo e crescimento. Os 12 bezerros com 36±4 kg de média e 30 dias de vida, foram divididos em grupo controle (n=6) e tratamento (n=6) que receberam o produto homeopático no leite durante os primeiros 30 dias e posteriormente no concentrado (fornecendo 10 g/dia do homeopático imunológico, baseado em Arsenicum album, Baptisia tinctoria, Calcarea carbonica, Iodum purum, Medicago sativa, Mercurius solubilis, Nux vomica, Pyrogenium e veículo de sacarose). Os animais do grupo tratamento tiveram ganho de peso corporal mais significativo de 1 a 30 dias do experimento (p≤0,05). Houve efeito do tratamento nos resultados hematológicos, com concentração de hemoglobina mostrando maior interação tratamento x dia no dia 90 (p≤0,05). As contagens de leucócitos, neutrófilos e linfócitos foram maiores no grupo de tratamento (p≤0,05). A concentração de albumina nos animais do grupo tratamento foi menor do que no grupo controle (p≤0,05). A concentração de globulina foi maior no grupo de tratamento (p≤0,05). Houve interação tratamento x dia para a concentração de tióis proteicos nos dias 30, 60 e 90, com níveis séricos mais elevados nos bezerros do grupo tratamento (p≤0,05). Os níveis séricos de espécies reativas de oxigênio foram menores nos bezerros do grupo de tratamento (p≤0,05). Os animais do grupo tratado apresentaram maior concentração de IgA. Durante o experimento, os níveis de ceruplasmina, haptoglobina, transferrina, glicoproteína ácida e IgG de cadeia leve também mudaram (interação tratamento x dia). Esses achados sugerem que o produto homeopático estimulou respostas imunológicas.