Caracterización del crecimiento de bovinos cebú en pruebas de comportamiento en pastoreo

Abstract

Artículo cientícorecibido: 03 de julio de 2016, aceptado: 10 de noviembre de 2016 RESUMEN. El objetivo fue caracterizar el crecimiento de bovinos Cebú en pruebas de comportamiento en pastoreo. Se utilizaron 15 990 datos de peso vivo, tomados entre 150 y 630 d de edad, de 3 198 machos con cinco pesadas cada uno: 1) peso al destete (PD), 2) peso inicio de prueba (PI), 3) primera pesada (P1), 4) segunda pesada (P2) y 5) peso nal de prueba (PF). Se contrastaron los modelos no lineales (MNL): Brody (BRO), Logístico (LOG), von Bertalany (BER) y Gompertz (GOM); en dos tipos de análisis (ANA1, ANA2) con NLMIXED de SAS. ANA1, con MNL mixtos (MNLM), al incluir el efecto aleatorio de un coeciente de regresión; y ANA2 con MNL, sin efectos aleatorios asociados a coecientes de regresión. La selección del modelo se realizó con los criterios error de predicción promedio; varianza del error de predicción; estadístico Durbin Watson; coeciente de determinación; criterio de información Akaike y criterio Bayesiano. Los pesos promedio (kg) ajustados al PD, PI, P1, P2 y PF fueron 175.9 ± 33.4, 182.5 ± 32.1, 225.8 ± 49.6, 266.8 ± 61.9 y 340.3 ± 68.1, respectivamente. Los análisis con MNLM (ANA1) presentaron mejores resultados, siendo el LOG el que presentó mejor ajuste, seguido de GOM, BER y BRO. Los resultados del ANA2 fueron sobre estimados y fuera de contexto para asociarse al crecimiento de bovinos; las curvas de crecimiento generadas con MNLM presentaron buena capacidad predictiva y estuvieron en función del proceso generador de los datos, que se reere al crecimiento del ganado Cebú.Palabras clave: modelos no lineales mixtos, ganadería tropical, curvas crecimiento, peso adulto, tasa crecimiento ABSTRACT. The objective was to characterize the growth of Cebu cattle in grazing performance tests. We used 15 990 live weight data, taken between 150 and 630 d of age, of 3 198 males with ve weights each: 1) weaning weight (WW), 2) initial test weight (IW), 3) rst weighing (W1), 4) second weighing (W2) and 5) nal test weight (FW). Nonlinear models (NLM) were compared: Brody (BRO), Logistic (LOG), von Bertalany (BER) and Gompertz (GOM). Two types of analyses (ANA1, ANA2) were carried out with the SAS NLMIXED procedure: ANA1 with mixed NLM (MNLM), by including the random eect of a regression coecient; and ANA2 with MNL, with no random eects associated with regression coecients. The model was selected using the criteria of mean prediction error; variance of the prediction error; Durbin Watson statistic; coecient of determination; Akaike information criterion and Bayesian criterion. The mean weights (kg) for WW, IW, W1, W2 and FW were 175.9 ± 33.4, 182.5 ± 32.1, 225.8 ± 49.6, 266.8 ± 61.9 and 340.3 ± 68.1, respectively. Analyses with MNLM (ANA1) presented better results, with LOG being the best t, followed by GOM, BER and BRO. The ANA2 results were overestimated and out of context to be associated

Effect of IGF-1 and LEP/ob SNPs on growth parameters of Blanco Orejinegro cattle

“…This model has been widely used to describe the growth curve in cattle, since it usually presents the best fits (Agudelo et al, 2008: Ramírez et al, 2009Rincón and Quintero, 2015), especially at ages after 6 months, since for first months of life it tends to underestimate the weight (Agudelo et al, 2008). However, for authors such as Dominguez-Viveros et al (2017) the model with the best performance for grazing zebu cattle was the logistic one.…”

“…; where: corresponds to the j-th weight of the i-th animal at time "t", β 0 : corresponds to the asymptotic weight when "t" tends to infinity and is commonly interpreted as the adult weight, β 1 : corresponds to a parameter of fit when Y ≠ 0 and when t ≠ 0, and indicates the proportion of asymptotic mature weight that is gained after birth, β 2 : corresponds to the maturity index represented as a percentage proportion of maximum growth with respect to the adult weight of the animal; t ij is the age in days at the j-th weighing of the i-th animal (Dominguez-Viveros et al, 2017). The fit of the models to the data was determined by the criteria of lowest sums of squares of the error (SQE), Akaike information criterion (AIC), Bayesian information criterion (BIC), and highest percentages of convergence (%C) and coefficient of determination (R 2 ).…”

Genetic-Quantitative Uni- and Bi-Trait Analysis for Growth Traits in the Colombian Creole Breed Blanco Orejinegro (BON)

“…cited by Dominguez Viveros et al, (2017), using the consecutive weights in the animal's life, and the BW as a starting point. Animals with at least four weighings and 800 days of age were employed.…”