B-spline polynomials models for analyzing growth patterns of Guzerat young bulls in field performance tests.

OBJECTIVE: The aim of this study was to identify suitable polynomial regression for modeling the average growth trajectory and to estimate the relative development of the rib eye area, scrotal circumference, and morphometric measurements of Guzerat young bulls. METHODS: A total of 45 recently weaned males, aged 325.8±28.0 days and weighing 219.9±38.05 kg, were evaluated. The animals were kept on Brachiaria brizantha pastures, received multiple supplementations, and were managed under uniform conditions for 294 days, with evaluations conducted every 56 days. The average growth trajectory was adjusted using ordinary polynomials, Legendre polynomials, and quadratic B-splines. The coefficient of determination, mean absolute deviation, mean square error, the value of the restricted likelihood function, Akaike information criteria, and consistent Akaike information criteria were applied to assess the quality of the fits. For the study of allometric growth, the power model was applied. RESULTS: Ordinary polynomial and Legendre polynomial models of the fifth order provided the best fits. B-splines yielded the best fits in comparing models with the same number of parameters. Based on the restricted likelihood function, Akaike's information criterion, and consistent Akaike's information criterion, the B-splines model with six intervals described the growth trajectory of evaluated animals more smoothly and consistently. In the study of allometric growth, the evaluated traits exhibited negative heterogeneity (b<1) relative to the animals' weight (p<0.01), indicating the precocity of Guzerat cattle for weight gain on pasture. CONCLUSION: Complementary studies of growth trajectory and allometry can help identify when an animal's weight changes and thus assist in decision-making regarding management practices, nutritional requirements, and genetic selection strategies to optimize growth and animal performance.

Aspectos epidemiológicos e distribuição da cisticercose bovina: uma revisão / Epidemiological aspects and distribution of bovine cysticercosis: a review

A cisticercose é uma parasitose cosmopolita relevante para a saúde pública, animal e economia. Neste estudo objetivou-se analisar dados epidemiológicos da ocorrência da cisticercose bovina em diferentes continentes. Promoveu-se revisão bibliográfica em artigos científicos, dissertações e teses sobre aspectos epidemiológicos e distribuição espacial da cisticercose bovina. Observa-se que a ocorrência dessa parasitose relaciona-se com diversos fatores de natureza socioeconômica, cultural e práticas de manejo empregues em distintos sistemas de produção animal. Baseada principalmente em dados de inspeção de carnes, a ocorrência dessa parasitose tende a ser subestimada, entretanto, muitos dos casos reportados da parasitose apontam ocorrência de forma endêmica em algumas regiões da África e América Latina. A heterogeneidade na distribuição espacial da parasitose, associada a variações de fontes de infecção dos animais, justifica a necessidade de implantação de práticas de vigilância sanitária e informações adicionais referentes às práticas de criação dos animais aos frigoríficos, possibilitando identificar riscos espidemiologicos e desenvolver medidas alternativas de controle do complexo teníase cisticercose.(AU)