George Rodrigo Beltrão da Cruz

Estimativas de parâmetros de curvas de lactação de bovinos

EnglishThe objective of this research was to identify the mathematical function that best fits the lactation curve of Guzera and Sindi cattle. 840 lactations records (467-Guzera, 373-Sindi) were used from animals raised at Carnauba ranch, in the town of Taperoa, Paraiba. Milk production control were taken every in 35 days, between years 1987 and 2004. Lactation records used contained a minimum of five and a maximum of ten controls. Six mathematical functions were fitted to the mean curve and individual lactations: polynomial inverse (PI), hyperbolic lineal (LH), gamma incomplete (GI), quadratic logarithmic (QL), lineal (L) and quadratic (Q) functions were fitted using an iteration process. Criteria used to verify fitting quality were: determination coefficient (Ra2), percent of deviation between the total observed estimated productions, and percent of typical curves. Residual distribution graph were used only to evaluate fitting of mean curve. Ra2 for mean curve fitting were always larger than 0.93. Good fits were also obtained (Ra2>0.80), in 61.4% and 66.7% of the lactations fitted by PI and GI functions, respectively, for Guzera cattle. For Sindi cattle, these values were 57.2% and 50.0%. PI and GI, respectively, were closest to the production oscillations throughout lactation, even though estimated deviations between total productions were observed and estimated that were similar to the other functions. All studied functions fitted well means curve data. For individual lactations, however, PI and GI give better estimates of total milk yields. portuguesO objetivo deste trabalho foi comparar algumas funcoes matematicas citadas na literatura, identificar a que melhor descreve a producao de leite e estimar alguns componentes da curva de lactacao de vacas Guzera e Sindi criadas na regiao semi-arida do estado da Paraiba. Foram utilizadas 840 lactacoes (467-Guzera; 373-Sindi) de animais pertencentes a Fazenda Carnauba, municipio de Taperoa, Paraiba. O controle leiteiro foi feito em intervalos de 35 dias, no periodo de 1987 a 2004. As lactacoes utilizadas continham no minimo cinco e no maximo doze controles. O ajuste foi feito para a curva media e para lactacoes individuais, utilizando-se seis funcoes matematicas. A funcao polinomial inversa (PI), linear hiperbolica (LHE), gama incompleta (GI), quadratica logaritmica (QL), linear (L) e quadratica (Q) foram ajustadas usando-se processos iterativos por meio de regressao nao-linear. Os criterios utilizados para verificar a qualidade do ajuste para cada funcao foram: coeficiente de determinacao ajustado (Ra2), percentagem de desvios entre as producoes totais observadas e estimadas e percentagem de curvas tipicas. Os graficos de distribuicao de residuos foram utilizados apenas para avaliar o ajuste para a curva media. Para a curva media, os valores de Ra2 foram superiores a 0,93 para todas as funcoes. Bons ajustes baseados nos Ra2>0,80 foram obtidos, respectivamente, para 61,4% e 66,7% das lactacoes ajustadas pelas funcoes PI e GI para vacas Guzera. Para vacas Sindi, esses valores foram de 57,2% e 55,0%, indicando boa qualidade no ajuste. As funcoes PI e GI acompanharam mais de perto as oscilacoes da producao ao longo da lactacao. Para curva media, todas as funcoes poderiam ser utilizadas, pois os desvios foram muito proximos. Para as lactacoes individuais, melhores estimativas dos componentes da curva de lactacao poderiam ser obtidos pelas funcoes PI e GI.

Use of mathematical models in the study of bodily growth in GIFT strain Nile tilapia

Objetivou-se com o presente estudo avaliar a acuracia de cinco modelos matematicos (Gompertz, Logistico, Linear Hiperbolico, Quadratico e Quadratico Logaritmico) para descrever a curva de crescimento de tilapia nilotica Oreochromis niloticus da linhagem GIFT e, realizar a caracterizacao da trajetoria do crescimento das partes corporais. Para tal, 1.000 alevinos com peso inicial de 2,4 g foram estocados em 20 tanques de alvenaria de 2 m3 numa densidade de 25 peixes m-3, por um periodo de 180 dias. Os animais foram alimentados diariamente, utilizando niveis de proteina e numero de refeicoes diarias de acordo com cada fase. Quinzenalmente, foram amostrados aleatoriamente 20 peixes, submetidos a um jejum de 48 h e abatidos por choque termico, para determinacao dos pesos do peixe inteiro, peles sem escamas, files sem pele, coracao, figado, brânquias e trato gastrointestinal. Os modelos Gompertz e Logistico foram os que mais se adequaram ao ajuste da curva de crescimento do peso vivo, do file e da pele, todavia, o Logistico subestimou os pesos assintoticos. Desta forma, sugere-se o Gompertz para descrever a curva de crescimento de tilapia nilotica da linhagem GIFT. De acordo com os parâmetros estimados pelo modelo Gompertz, a tilapia nilotica atinge a idade de maximo crescimento do file e pele antes da idade do peso vivo. Dentre os orgaos estudados, o crescimento do trato gastrointestinal e brânquias e mais precoce do que o do coracao e figado.

Substituição parcial do milho por sorgo granífero na alimentação de suínos nas fases de creche, crescimento e terminação

The study evaluated the effect of partial substitution of corn by sorghum in diet of castrated pigs and the effects on performance, carcass traits and economic feasibility. It were used 27 crossbred barrows from commercial line with 19.66 ± 2,92kg of initial live weight, divided in three groups with increasing rates of sorghum - 0%, 25% and 50% - replacing corn, distributed in a completely randomized design. The trial evaluated: daily weight gain, daily feed intake and feed:gain ratio, backfat thickness and blood biochemical parameters - urea, total proteins, creatinine, glucose, triglycerides and cholesterol. For carcass traits it was evaluated: hot and cold carcass weight, hot and cold carcass yield, pH and temperature in hot and cold carcasses and industrial weight cuts. For economy feasibility was calculated the cost of feed consumed, cost of pig kg, average cost index and economy efficiency rate. It was used regression analysis to evaluate the productive variables. No effects were found for performance data and carcass traits. For the biochemical variables, the effects were linear for urea and total protein, with animals in control group (0% of sorghum) showing higher rates. The bioeconomical performance showed that 50% sorghum had the lowest cost and the highest rate of economic efficiency. Thus, it was concluded that substitution of corn by sorghum at levels up to 50% of the diet represents an alternative to sustainability of regional swine production.

Calculation of the costs and evaluation of incomes in different systems of production of goat milk in Cariris Paraibanos

The study aimed at calculating milk production cost and evaluating the income in goat milk farm activity by production systems. The production systems are located in the sub region of Cariris Paraibanos and they were defined by criteria of technical and economical efficiency, with grouping method by multivariate data analysis and formation of five groups. The method used for production cost was the operational cost, and the criterion adopted for the conversion of the milk activity cost for the cost of the milk was the participation of the milk income in the gross income of the activity. The criteria adopted for analysis of income were gross margin and net margin. In the count of goat milk production cost the values were R

Substituição parcial do milho por sorgo granífero na alimentação de matrizes suínas primíparas durante a lactação

0.67/L R

Substituição parcial do milho por sorgo granífero na alimentação de matrizes suínas primíparas nos períodos de puberdade e gestação

0.73/L, R

Physicochemical and sensory characteristics of yoghurts made from goat and cow milk

0.80/L, R

Curva de crescimento de caprinos mestiços no estado da Paraíba

0.88/L and R

Avaliação genética de bovinos Guzerá utilizando-se a produção de leite e de gordura no dia do controle

1.21/L for the production systems 1, 2, 3, 4 and 5. Systems of production 1 and 2 with high technology and net margin of R

Efeito das condições de manejo nas características sensoriais de banana (Musa spp.) cv. Pacovan

9,147.30 and R