Fabyano Fonseca e Silva

Produção, composição e rendimento em queijo do leite de ovelhas Santa Inês tratadas com ocitocina

Objetivou-se avaliar a producao, a composicao e o rendimento (na fabricacao de queijos) do leite de ovelhas Santa Ines tratadas ou nao com ocitocina. Os animais foram mantidos em regime de confinamento e receberam uma dieta com 12% de PB e 65% de NDT. As ovelhas foram distribuidas em dois tratamentos: ordenha manual com injecao endovenosa de tres UI de ocitocina e ordenha manual sem injecao de ocitocina (grupo controle). Realizou-se uma ordenha diaria, de modo que, ate a desmama, as ovelhas permaneceram diariamente com os cordeiros durante 14 horas. Os cordeiros foram desmamados aos 60 dias e as ovelhas continuaram sendo ordenhadas uma vez ao dia ate o final da lactacao. Foram coletadas amostras de leite para analise dos teores de gordura, de solidos totais e de solidos desengordurados. A duracao media da lactacao foi de 225±27,24 e 210±38,77 dias para as ovelhas controle e tratadas com ocitocina, respetivamente. Ate os 133 dias de lactacao, o tratamento com ocitocina (141,63±51,52 kg) foi superior ao controle (89,39±16,65 kg), entretanto, durante todo o periodo de lactacao, nao diferiu (169,64 ± 71,05) do controle (119,72±32,73). As porcentagens de gordura (5,84±0,44 e 4,96±0,47), solidos totais (17,40±0,42 e 16,18±0,57) e solidos desengordurados (11,57±0,15 e 11,22±0,25) no leite foram influenciadas pela aplicacao de ocitocina. Os resultados revelaram diferenca significativa para as ovelhas tratadas com ocitocina, as quais apresentaram maior produtividade e, inclusive, melhor composicao quimica do leite. A aplicacao de ocitocina e recomendada para animais nao adaptados a rotina de ordenha. O leite das ovelhas Santa Ines apresentou rendimentos de 4,80; 8,29 e 5,99 L/kg para os queijos tipo azeitao, pecorino e roquefort, respectivamente.

Agrupamento de curvas de progresso de requeima, em tomateiro originado de cruzamento interespecífico

The objective of this work was to estimate the progress curves of late blight in tomato genotypes, and to identify tomato genotype groups resistant to this disease. Twenty-five hybrid tomatoes, originated from crosses between four fresh market cultivars, one access from the Banco de Germoplasma de Hortalicas (BGH) of Universidade Federal de Vicosa (UFV), and five F8 lines (Solanum lycopersicum x Solanum habrochaites), selected as late blight resistance source,xa0were evaluated. Plants were inoculated with a sporangium mixture of Phytophthora infestans, and then, six evaluations for late blight severity were carried out every three days. The exponential model was fitted to the data of late blight severity percentage, and the obtained parameter estimates - initial incidence of disease (yo )and progress rate of disease (r) - were submitted to the multivariate analysis of variance (Manova). The means of these estimates, obtained for each genotype, were submitted to the cluster analysis. An optimal number of eight distinct groups was observed, which made it possible to identify the genotypes belonging both to the resistant and susceptible groups. The experimental hybrids Ikramxa0xxa073xa0A, Nemo-Nettaxa0xxa0133xa0A, Ikramxa0xxa0163xa0A and Nemo-Netta x 163xa0A showed the smaller rate of disease progress and, therefore, higher late blight resistance.

Selection of models of lactation curves to use in milk production simulation systems

The objective of this study was to select models of lactation curves with a better adjustment to the observed data in models of milk production simulation systems. A data base on 6,459 recordings of daily milk production was used. These data were obtained from monthly and fortnightly controls of milk between 2004 and 2007, from 472 lactations of animals from ten different milking cow herd farms. Based on rolling averages of milk production (MP-L/day) per cow, the ten herd farms were divided into low (L 20). Data were also divided according to the lactation numbers in first, second, third or greater. Eight lactation curve models commonly used in literature were compared. The models were individually adjusted for each lactation. The goodness of fit used for comparison of those models was the coefficient of determination, mean square error, mean square prediction error and the Bayesian information criterion. The values for the goodness of fit obtained in each model were compared by using 95% probability confidence interval. Wilmink (1987) model showed a better adjustment for cows of the first lactation numbers, whereas the Wood (1967) model showed a better adjustment for cows of the third or greater lactations numbers for the low milk production groups. Wood model showed a better adjustment for all the lactation numbers for the medium milk production group. Dijkstra (1997) model showed a better adjustment for all lactation numbers for the high milk production group. Despite of being more recent, the model by Pollott (2000), mechanist based and with a higher number of parameters, showed a good convergence for the used data.

Evaluation of a dynamic simulation model for milk production systems

Objetivou-se desenvolver e avaliar um modelo dinâmico de simulacao com componentes estocasticos para avaliacao de sistemas de producao de leite. O modelo de simulacao foi desenvolvido utilizando-se os programas STELLA 9.0, ZooCalc 1.0 e planilhas eletronicas. A estrutura fisica do rebanho foi dividida em 15 modulos interligados, que representam categorias ou subdivisoes de categorias. Para simulacao do peso corporal dos animals em crescimento e em lactacao, assim como da producao e composicao do leite, foram utilizados modelos matematicos obtidos na literatura e, para calculo de exigencias nutricionais e balanceamento das dietas dos animals, planilhas eletronicas. Apos a reducao do custo, cada racao foi avaliada pelo programa ZooCalc 1.0. Para avaliar se o modelo de simulacao estaria funcionando de forma coerente com o esperado, foram obtidas as respostas medias de alguns indicadores de tamanho, de indicadores zootecnicos e economicos e a variacao da area utilizada para producao de milho para silagem, do intervalo de partos e da idade a primeira inseminacao. Para avaliar a capacidade do modelo em gerar valores simulados que se aproximem da realidade, foi medido o grau de associacao linear entre os valores gerados pelo modelo e observados em situacao pratica. As analises de sensibilidade comprovaram que os valores produzidos pelo modelo de simulacao se comportam de acordo com o esperado, em resposta as variacoes da area utilizada para producao de milho para silagem, do intervalo de partos e da idade a primeira inseminacao. Existe correlacao entre os valores gerados pelo modelo de simulacao e os observados na pratica, e o grau de associacao linear pode ser considerado elevado.

Genomic prediction for additive and dominance effects of censored traits in pigs

Age at the time of slaughter is a commonly used trait in animal breeding programs. Since studying this trait involves incomplete observations (censoring), analysis can be performed using survival models or modified linear models, for example, by sampling censored data from truncated normal distributions. For genomic selection, the greatest genetic gains can be achieved by including non-additive genetic effects like dominance. Thus, censored traits with effects on both survival models have not yet been studied under a genomic selection approach. We aimed to predict genomic values using the Cox model with dominance effects and compare these results with the linear model with and without censoring. Linear models were fitted via the maximum likelihood method. For censored data, sampling through the truncated normal distribution was used, and the model was called the truncated normal linear via Gibbs sampling (TNL). We used an F2 pig population; the response variable was time (days) from birth to slaughter. Data were previously adjusted for fixed effects of sex and contemporary group. The model predictive ability was calculated based on correlation of predicted genomic values with adjusted phenotypic values. The results showed that both with and without censoring, there was high agreement between Cox and linear models in selection of individuals and markers. Despite including the dominance effect, there was no increase in predictive ability. This study showed, for the first time, the possibility of performing genomic prediction of traits with censored records while using the Cox survival model with additive and dominance effects.