A total of 17 356 test-day milk yield (TDMY) records from 642 first lactations of Alpine goats were used to model variations in lactation curve using random regression models (RRM). Orthogonal Legendre polynomials and B-splines were evaluated in order to obtain adequate and parsimonious models for the estimation of genetic parameters. The analysis were performed using a single-trait RRM, including the additive genetic, permanent environmental and residual effects. We estimated the mean trend of milk yield, and the additive genetic and permanent environmental covariance functions through random regression using different orders of Orthogonal Legendre polynomial (three to six) and B-spline functions (linear, quadratic and cubic, with three to six knots). This study further evaluated different number of classes of residual variances. The covariance components and the genetic parameters were estimated using the Restricted Maximum Likelihood method. Heritability estimates presented similar trends for both functions. RRMs with a higher number of parameters better described the genetic variation of TDMY throughout the lactation. The most suitable RRM for genetic evaluation of TDMY of Alpine goats is a quadratic B-spline function with six knots, for the mean trend, curves of additive genetic and permanent environmental effects and five classes of residual variance.

RESUMO -Foram utilizados 10.238 registros semanais de produção de leite no dia do controle leiteiro provenientes de 388 primeiras lactações de cabras da raça Saanen visando comparar diferentes modelos de regressão aleatória (MRA).Primeiramente, foram comparados cinco modelos, cujos termos exponenciais da função de Wilmink assumiram os seguintes valores -0,0350; -0,0500; -0,0565; -0,0680 e -0,1000 (W0350, W0500, W0565, W0680 e W1000, respectivamente), Palavras-chave: função de Wilmink, leite, modelagem, produção de leite no dia do controle, variância residual Random regression models in the milk yield evaluation in Saanen goatsABSTRACT -It was used 10,238 weekly test day records from 388 first lactations of Saanen goats with the objective of comparing random regression models (RRM). Firstly, it was compared five models, whose exponential terms of Wilmink function assumed the following values: -0.0350; -0.0500; -0.0565; -0.0680 and -0.1000 (W0350, W0500, W0565, W0680 and W1000, respectively) by considering homogeneity of residual variance over the lactation period. The value -0.0500 was kept in the model W0500 whereas models W0350, W0565, W0680 and W1000 used values -0.0350; -0.0565; -0.0680 and -0.1000, respectively, replacing the value -0.0500, proposed by the original model used in dairy cattle. After choosing the best model according to ln L, homogeneity and heterogeneity for residual variance: homogeneity, two classes, three classes, four classes, five classes and six classes along the lactation were evaluated by using AIC, BIC and ln L criteria. According to criterion used, W0350 presents the best fit among the evaluated models. With regard to residual variance, the use of six classes over lactation is indicated by AIC, BIC, ln L and likelihood ratio test. Heritability estimates over lactation, for the best model, ranges from 0.07 (2 nd lactation week) to 0.25 (20 th lactation week).

The aim of this study was to evaluate different non-linear regression models to describe the growth curve of male and female meat quail. The study involved 30,410 records of body weight originally measured weekly from the 1st to the 42nd day of life of meat quail participating in the Breeding Program of the Federal University of Vales do Jequitinhonha e Mucuri. Body weight was separated into the male and female classes and subjected to the non-linear Brody, Gompertz, Logistic, MMF (Morgan-Mercer-Flodin), Richards, and van Bertalanffy models. The models were evaluated with respect to the adjustment of predicted growth curves in relation to observed values. No convergence was obtained with the Brody model. The other models yielded good AI (asymptotic index) values, and the MMF model was the most suitable to predict the weight of males, with an AI of 33.59, whereas the Gompertz model, with an AI of 36.100, was the most suitable to predict the weight of females. Therefore, in the present study, the Gompertz and MMF models best fitted the data for males and females, with an R2aj greater than 0.92. Results point to the use of both methods to describe the growth of these animals, irrespective of sex.

ResumoObjetivou-se avaliar o desempenho produtivo e nutricional de bezerras lactentes recebendo mistura mineral ou suplementos múltiplos e a produção de leite, o consumo e a digestibilidade do pasto consumido por vacas de corte, em pastagens de Uruchloa decumbens. Utilizaram-se 48 bezerras de corte, lactentes, com idade média de 5 meses e peso médio inicial de 125,4 + 1,34 kg, e suas respectivas mães com peso inicial médio de 435,2 + 10,3 kg. O delineamento experimental foi o inteiramente casualizado. Os suplementos continham aproximadamente 25% de proteína bruta (PB) e substituição progressiva do farelo de soja (FS) pelo farelo de algodão 38% (FA) aos níveis de 0; 33; 67 e 100% para os tratamentos FA 0 , FA 33 , FA 67 e FA 100 , respectivamente. Adicionou-se ureia aos suplementos visando ajustar o teor proteico dos suplementos. Os animais do tratamento controle (MM) receberam exclusivamente mistura mineral ad libitum; nos demais tratamentos os suplementos múltiplos foram fornecidos na quantidade de 0,5 kg/animal/dia. O ganho médio diário (g) foi 687,8; 733,2; 820,0; 760,6 e 764,5, respectivamente, para os tratamentos MM, FA 0 , FA 33 , FA 67 e FA 100. As bezerras suplementadas apresentaram maior ganho em peso. Não se verificou efeito dos níveis de FA nos suplementos múltiplos (P>0,10) sobre o ganho médio diário. Os consumos em kg/dia de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), carboidratos não fibrosos (CNF), MS digerida e nutrientes digestíveis totais foram superiores (P<0,10) em animais suplementados com suplementos múltiplos em relação aos animais suplementados apenas com mistura mineral. Entre os níveis de substituição do FS por FA observou-se efeito linear decrescente com o aumento do nível de FA sobre o consumo de MS digerida e fibra em detergente neutro digerida. Os coeficientes de digestibilidade aparente total da MS, MO, PB e CNF foram superiores (P<0,10) em animais suplementados. Entre os níveis de substituição do FS pelo FA observou-se efeito linear decrescente sobre a digestibilidade da fibra em detergente neutro. A suplementação das bezerras não influenciou o desempenho das vacas, a produção de leite e o consumo

RESUMO Objetivou-se no presente trabalho determinar herdabilidades de características de desempenho produtivo e reprodutivo de diferentes grupos genéticos de matrizes de codornas de corte, estimando os parâmetros genéticos por nascimento, 7, 14, 21, 28, 35, 42, 77, 112 birth, 7, 14, 21, 28, 35, 42, 77, 112