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Thesis (M. Ag.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 69-71). Also available on the World Wide Web.

Aberdeen Angus (originated in Scotland) is the second most common beef breed in the Czech Republic due to its resistance to adverse climatic events, modesty, earliness, ease of calving, low birth weight of calves and good maternal instincts of cows. The main economic indicator of suckler cows rearing is the number of born and weaned calves. Production of twins is possible way to improve these indicators. The aim of this thesis was to compare the growth potential of twins of Aberdeen Angus beef breed with individuals who were born as singletons. The work is focused on comparing the weight at birth, in 120 and 210 days of age. Most twins in the population of Aberdeen Angus breed reared in the Czech Republic in 2009-2013 was born in 2012 - 9.44 % (270 pcs.), the least in 2013 - 6.67 % (184 pcs.). The incidence of twins by birth order increased from 1 to 3 birth order (78, resp. 130, resp. 131 pcs.) as further increasing order resulted into decline of twin's incidence. The difference in weight between twins and singletons at birth was 5.81 kg, in 120 days 28.32 kg and 37.32 kg 210 days (P 0.001). Differences within twins by sex were for bulls and heifers statistically significant (P 0.001). The relationship between weight at birth and calving ease was also investigated - in the case of twins relationship was not statistically significant (P> 0.05). The lowest mortality rate of twins was in 2013 - 8.70 % (16 pcs.), the highest mortality rate was in 2012 36.67 % (99 pcs.). Most twins were born in 2011 (179 pcs.), whereas least twins were born in 2010 (160 pcs.).

Call number: LD2668 .T4 1985 K74 / Master of Science

The objectives of the current study were: 1) to examine serum bPAG concentration during pregnancy, and in the post-partum period in relation to the overall nutritional and metabolic status and post-partum anoestrous period; 2) to investigate bPAG decay models for postulating distribution and metabolism of bPAG in the blood circulation using half-life (t1/2) and to compare the t1/2 values between breeds and nutritional treatments for the clearance of bPAG; 3) to examine the suitability of the radioimmunoassay (RIA) for measuring bPAG in urine, saliva and milk, to investigate temporal relationships between bPAG in these fluids and that in the serum, and to assess the potential of bPAG in these fluids for pregnancy diagnosis in cows. Estimation of total bPAG disappearance from plasma per day during week 1 post-partum did not differ between the breeds. Urinary bPAG, over the same period of time, was lower for Welsh Black than Simmental and Charolais cows (0.45 vs 0.53 and 0.59 nmol (s.e.d 0.03) p<0.05) but not for Aberdeen Angus cows (0.48 nmol); bPAG in saliva was lower for Welsh Black than Charolais and Aberdeen Angus cows (1.65 vs 2.42 and 2.49 nmol (s.e.d 0.11) p<0.05) but not for Simmental cows (1.44 nmol/1), and bPAG measured in milk (whole) was lower for Charolais than Simmental cows (0.26 vs 0.47 nmol (s.e.d 0.06) p<0.05) but not for Aberdeen Angus (0.38 nmol/1) and Welsh Black cows (0.37 nmol/1). Total body elimination of bPAG in urine, saliva and milk accounted only for 5.28 % of the total plasma bPAG. Total body elimination of bPAG in urine, saliva and milk accounted for only 5.28 % of the total plasma bPAG. The remaining 94.72 % of bPAG may have been metabolished and was undetectable by the current RIA technique. A theoretical assessment for potential use of bPAG RIA for pregnancy diagnosis using urine, saliva and milk showed that the minimum detection limits of measuring bPAG in these fluids were reached and / or exceeded by Day 200 of gestation, or later. Consequently, assay of bPAG in these fluids for early pregnancy diagnosis would not be appropriate unless the sensitivity of the assays is improved considerably, or prior assay sample extraction/concentration is carried out.

Orientador: Henrique Nunes de Oliveira / Coorientador: Márcia Cristina de Sena Oliveira / Banca: Simone Cristina Méo Niciura / Banca: Rodrigo Giglioti / Resumo: A bovinocultura é um setor com importante destaque no agronegócio brasileiro. O carrapato Ripicephalus (Boophilus) microplus é responsável por perdas econômicas significativas aos pecuaristas e é vetor de hemoparasitoses como Anaplasma spp e Babesia spp. Sabe-se que os bovinos Bos taurus taurus são mais susceptíveis à infestação por carrapatos do que Bos taurus indicus. Acredita-se que o mesmo ocorra para a infecção por Babesia bovis. Neste trabalho, foram avaliados, em duas colheitas, 355 bovinos da raça Angus, pertencentes a uma fazenda de Uruguaiana-RS, nos quais foram realizadas contagens de carrapatos e colheitas de amostras de sangue para quantificação de B. bovis, pela técnica de qPCR, e genotipagem com chip de 150.000 marcadores SNP. Para qPCR utilizaram-se sequências iniciadoras que flanqueiam um fragmento do gene do citocromo B (mt-cytB), como oligonucleotídeos iniciadores. Após genotipagem dos bovinos com o chip Gene Seek Genomic Profiler™ (GGP-HD) da Illumina Infinium®, foi realizado imputação de genótipos, para recuperação de genótipos faltantes, e controle de qualidade. Foi realizada análise de associação genômica ampla (GWAS), para cada uma das características, infecção por B. bovis e resistência a carrapatos, através do método denominado "Single Step Genomic BLUP" (ssGBLUP). Todos os animais apresentaram infestação por carrapatos e infecção por B. bovis, determinada pela qPCR, e altos valores médios para ambas as características. Algumas regiões cromossômicas ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The cattle industry is a sector with importance in the Brazilian agribusiness. The Ripicephalus (Boophilus) microplus is responsible for economic losses and is a vector for hemoparasitoses, such as Anaplasma spp and Babesia spp. It is known that the Bos tauros animals are more susceptible to infestation by ticks when compared with infestation in Bos indicus animals. It is believed that the same behavior keeps for infection by Babesia bovis. They were evaluated, in two collections, 355 Angus cattle, from a farm in Uruguaiana city, estate of Rio Grande do Sul, where were performed tick counts, quantification of B. bovis by qPCR and genotyping with a 150K chip. Were used as primers, in the qPCR, sequences that flanking the fragment of the cytochrome b gene. The technique was standardized and optimized using specimens of isolates of B. bovis. After genotyping, imputation was carried out, for recovery of missing genotypes, and quality control. Genome association analysis was performed (GWAS), to each of the characteristics, through the method called "Single Step Genomic BLUP" (ssGBLUP). All animals showed tick infestation and infection by B. bovis and high average values for both characteristics. Some regions on chromosomes were identified as significant to the characteristics tick infestation and infection by B. bovis, and seven chromosomes, identified in the present study, were already described in other studies. The present study agrees with other results indicating that the qP... (Complete abstract click electronic access below) / Mestre

Orientador: Elton Eustáquio Casagrande / Manoel Fernando Martins / Ana Claudia Fernandes Terence / Resumo: A cadeia de carne bovina possui posição de destaque no contexto da economia rural brasileira, ocupando vasta área do território nacional e respondendo pela geração de emprego e renda de milhões de brasileiros. Contudo, para atender as demandas da sociedade moderna, é preciso avançar na produção de produtos mais diferenciados. Neste sentido, ganham relevância as estratégias empresariais nos diversos elos da cadeia produtiva da carne bovina, sobretudo no subsistema de industrialização. Na cadeia produtiva da carne bovina brasileira, um dos programas de destaque com essa finalidade é o Programa Carne Angus Certificada. Este trabalho, classificado como uma pesquisa aplicada, de natureza exploratória, de abordagem qualitativa, no contexto de uma análise de interação setorial, feita através de um procedimento de estudo multicaso, descreveu e analisou a estrutura competitiva e o comportamento estratégico dos frigoríficos participantes do Programa Carne Angus Certificada em São Paulo, com suporte das teorias do Modelo das Cinco Forças de Porter e das Tipologias Estratégicas de Miles e Snow. A coleta de dados se deu através de entrevista semiestruturada, realizada com quatro indústrias frigoríficas participantes do programa no estado, que contou com roteiro pré-determinado e perguntas avaliativas feitas após as respostas dadas com auxílio de itens da escala Likert (estrutura competitiva) e respostas às questões de múltipla escolha (comportamento estratégico). Os resultados para a estr... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The beef production chain has a prominent position in the context of the Brazilian rural economy, occupying a large area of the national territory and responding to the generation of employment and income for millions of Brazilians. However, to meet the modern society demands, it is necessary to move forward in the production of differentiated products. In this sense, corporate strategies gain importance in the beef production chain channels, especially in the industrialization subsystem. In the Brazilian beef production chain, one of the main programs for this purpose is the Certified Angus Beef Program. This work, classified as an applied research, of an exploratory nature, with a qualitative approach, in the context of a sectorial interaction analysis, made through a multicase study procedure, described and analyzed the competitive structure and strategic behavior of the meatpackers participating in the Program Angus Beef Certified in São Paulo, with support from Porter's Five Forces Model theories and Miles and Snow Strategic Typologies. Data were collected through a semistructured interview, conducted with four meatpacking industries participating in the program in the state, which had a predetermined script and evaluative questions made after the answers given using Likert scale items (competitive structure) and responses to multiple choice issues (strategic behavior). The results for the competitive structure indicated that the threat of new competitors and the power o... (Complete abstract click electronic access below) / Mestre

The thesis is focused on the growth intensity of Aberdeen Angus, Charolais and Limousine. In experiment A, 152 male animals were monitored. These bulls came from organic and conventional breeding. For bulls, the date of birth, birth weight, father's line, date of sale, and live weight of bulls at sale were followed. Experiment B included 88 female heifers. Within each breed heifers came from conventional and organic breeding. Heifers were monitored for birth date, birth weight, father's line, weight at 120 and 210 days. Significant differences (p < 0.01) were found in the evaluation of the weights of individual monitored parameters between bulls and heifers, which are confirmed by the rule that females have lower birth weight (37 kg) than males (40 kg). However, at 120 days of age, weights were higher in heifers (177 kg) compared to bulls (148 kg). In the evaluation of breeding effect, the highest (p < 0.01) weights were found in Charolais (bulls 163 kg, heifers 187 kg).

The objectives of this study were: (1) to estimate the effects of certain non-genetic sources of variation in weight, gnde, and condition of beef cows; (2) to estimate the heritability of weight, grade. and condition of beef cows; and (3) to estimate the genetic, phenot;rpic, and environmental correlations between weight, grade, and condition of beef cows. Weights, grades., and condition scores taken on 1371 Angus cows were used to evaluate the genetic and environmental nature of these traits. This sample of cows represented 365 sire groups. Four models were used in this study: 1. Model A - Cow weight and grade were considered dependent variables; herds and sires within herds were considered random independent variables; and season, age, condition, nursing status, and their interactions were considered fixed independent variables. Least-squares procedures involving Henderson's (1953) Method II were used to adjust tor fixed effects and to obtain variance and covax-iance components. Heritability estimate and correlation coefficients were obtained by paternal half-sib analysis. 2. Model B differed from Model A in that condition 3 score was considered a dependent variable instead of an independent variable. 3. Model C was the same as Model A except that the coefficients (kₒ and k₂) for the within sire (σw²) component of variance included in the among sire and herd adjusted expected mean squares (EMS) were considered unity whereas as in Model A they were calculated according to Method II of Henderson. 4. Model D - Heritability estimates were computed by doubling the estimate of intra-sire regression of offspring on dam from 198 dam-daughter pairs representing 63 sire groups. The dam-daughter pairs were part of the group or 1371 cows. The results of this study indicated that season, age, condition score, nursing status, and age by nursing status remain significant when condition score was not considered as a fixed environmental effect (Model B). However, a comparison of the magnitude of the mean squares for these effects in Models A and B indicated that season, age, and nursing status are highly confounded with condition score. Season and flesh condition were found to have a significant effect on grade of beef cows when they were included in the same model (Model A). When condition score was not included (Model B) age had a significant effect on grade. Age, season, and nursing status were found to have a significant effect on flesh condition (Model B). Paternal half-sib heritability estimates for cow weight using Models A, B, and C were 0.38 ± 0.11, 0.29 ± 0.11, and 0.56.± 0.11, respectively. Estimates for grade from the same models were 0.49 ± 0.11, 0.43 ± 0.11, and 0.67 ±0.12, in that order. Estimates from Model A should be the most reliable. The differences in the estimates from Models A, B, and C, illustrate that variation in heritability estimates is not entirely due to genetic differences. Considerable variation can occur depending on how much adjustment has been made to fixed effects, and the methods used in estimating the variance and covariance components. The heritability estimates of cow weight and grade obtained by intra-sire regression of offspring on dam were 0.22 ± 0.14 and 0.10 ± 0.06, respectively. The paternal half-sib heritability estimate for condition score was 0.31 ± 0.11, which implies that adjusting cow weights and grades for condition may actually involve adjusting for genetic differences as well as differences due to environmental influences. The correlation between weight and grade or beef oowe was found to be largely genetic whereas the correlation between condition and cow weight or grade was primarily environmental. / Ph. D.