02317naa a2200277 a 450000100080000000500110000800800410001910000220006024501140008226000090019652014480020565300130165365300270166665300280169365300260172170000180174770000260176570000220179170000230181370000220183670000220185870000250188070000220190570000280192777300840195521353142021-10-14       2021    bl uuuu     u00u1 u    #d1 aCAVALCANTE, D. H.  aCovariance functions under B-spline polynomials to model Polled Nellore cattle growth.h[electronic resource]  c2021  aB-spline functions have been used in random regression models (RRM) to model animal weight from birth to adulthood because they are less vulnerable to common difficulties of other methods. However, its application to model growth traits of Polled Nellore cattle has been little studied. Therefore, this study aimed to evaluate polynomial functions of different orders and segment numbers to model effects associated with the Polled Nellore cattle growth curve. For this purpose, we used 15,148 weight records of 3,115 animals aged between 1 and 660 days and reared in northern Brazil and born between 1995 and 2010. Random effects were modeled using B-spline polynomials. As random effects, we considered the direct and maternal genetic additives, as well as direct and maternal permanent environments. As fixed effects were included contemporary group, cow age at calving (linear and quadratic) and fourth order Legendre polynomials to represent average growth curve. The residue was modeled by considering seven age classes. The bestfitted model was the one that considered cubic B-spline functions with four knots for direct additive genetic effects and three knots for maternal genetic, animal permanent environment, and maternal permanent environment effects (C6555). Therefore, covariance functions under B-spline polynomials are efficient and can be used to model the growth curve of Polled Nellore cattle from birth to 660 days of age.  aLegendre  aParâmetros Genéticos  aPolinômios segmentados  aRegressão aleatória1 aLUZ, C. S. M.1 aOLIVEIRA, M. R. A. de1 aFONSECA, W. J. L.1 aEVANGELISTA, A. F.1 aMARTINS FILHO, R.1 aMALHADO, C. H. M.1 aAZEVEDO, D. M. M. R.1 aSANTOS, K. R. dos1 aSOUSA JÚNIOR, S, C, de  tSemina: Ciências Agrária, Londrinagv. 42, n. 6, supl. 2, p. 3977-3990, 2021.