E. C. Pimenta Filho

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.

Aspectos ambientais e genéticos da prolificidade em caprinos utilizando modelos bayesianos de limiar e linear

Variance components and genetic parameters of the litter size trait, using Bayesian inference under linear and threshold animal model were estimated. The litter size of crossbred goats was studied with information regarding a period of eight consecutive years. Analyses were performed with 500,000 cycle chains. The burn-in of the 15,000 baseline values was considered and these were taken every 250 cycles to obtain a posteriori distribution with 1,940 effective samples. Statistical analyses showed that the effects of coverage month, delivery order and linear effect of weight on coverage were significant. The heritabilities were 0.03 and 0.18 for linear and threshold models respectively. The threshold model proved to be suitable, producing higher estimates regarding the estimated parameters.

Influence of the climatic environment and duration of labor on the mother-offspring interaction in Morada Nova sheep.

The objective of this study was to confirm the influences of stress from labor and climate on the formation of the mother-offspring bond in Morada Nova sheep in the first 2 h after delivery or at the moment of the first suckling of the newborn. The data were collected from 80 Morada Nova ewes (25 primiparous and 55 multiparous) and their lambs in 2 periods of the year. On the basis of the average length of parturition and the black globe temperature-humidity index (BGTHI) at the time of the birth, the ewes were grouped into 3 classes corresponding to the length of parturition, classified as short (less than 15 min), medium (between 15 and 30 min), or long (more than 30 min). Similarly, the BGTHI at the moment of birth was classified into 1 of 3 ranges: low (less than 65), intermediate (greater than 65 but less than 80), and high (greater than 80). For the characterization of mother-offspring behavior, evaluations were performed in the first 2 h after birth or until the moment of the first suckling of the newborn. Maternal factors such as maternal grooming, facilitating sucking, frequency of low-pitched bleats, and latency to groom were recorded. For the lamb, attempts to seek the udder, the frequency of low-pitched bleats, latency to first reaction, latency to stand, and latency to suckle were recorded. The lambs were slower (P < 0.05) to stand and suckle when they were born in conditions of a BGTHI below 65. The latencies to stand and suckle were greater (P < 0.05) in newborn lambs born during labor that took more than 30 min. For maternal behaviors, activities such as maternal grooming and the facilitation of suckling were greater (P < 0.05) during the time periods with higher bioclimatic index values. Moreover, the dams cleaned or licked (maternal grooming) the newborns for a lower percentage of time (P < 0.05) when the labor lasted longer than 30 min. From the present study, it can be concluded that newborn Morada Nova lambs are slower to stand and suckle when born under BGTHI conditions below 65. Furthermore, prolonged labor harms the mother-offspring bond, especially in terms of the dams ability to clean (maternal grooming) her lambs body and facilitate its first suckling.

Caracterización fenotípica de la Raza Caprina Azul en el Nordeste Brasileño

El presente trabajo tuvo como objetivo caracterizar fenotipicamente un rebano de cabras azules, pertenecientes a la granja Carnauba, municipio de Taperoa, Estado de Paraiba, Brasil, con el proposito de contribuir a la homologacion del patron racial en el Ministerio de Agricultura. Fueron evaluadas 62 hembras azules con edades a partir de dos anos y peso medio de 40,3 kg, tomandose las siguientes medidas morfometricas: longitud corporal (71,5±5,6 cm), altura a la cruz (59,0±4,3 cm), perimetro toracico (76,9±4,8 cm), longitud de las orejas (12,6 cm), formato de los cuernos (bien implantados, simetricos, dirigidos hacia arriba, hacia detras y hacia afuera, con pequenas curvaturas hacia el frente en las extremidades y color ceniza oscuro). Los animales presentaron tres patrones distintos de capa: ceniza claro, ceniza azulado y ceniza azulado muy oscuro. Este estudio contribuira al fortalecimiento de los trabajos de conservacion de esta raza, que se encuentra en estado critico debido a cruzamientos absorbentes e indiscriminados con otras razas exoticas.