Modeling the growth pattern of in-season and off-season Ross 308 broiler breeder flocks

Abstract

Growing the Ross broiler parent according to the target growth curve ensures that males and females achieve optimum lifetime performance and well-being. Accurate control of growth will lead to uniformity and sexual maturity, which are of crucial importance for the production of hygienic, healthy, and fertile eggs of high quality. This study examined the growth of Ross 308 broiler breeder flocks from hatch to 35 wk of age to identify which growth model would describe the growth of these animals most accurately. Growth was measured and modeled using linear and nonlinear functions, and the experimental growth curves were compared with target curves from the Parent Stock Management Manual for Ross 308 (Aviagen). Broiler breeder flock R6 (in-season from February until October) and flock R7 (off-season from August until April) were kept in an environmentally controlled breeder house from hatch until 35 wk of age. Three nonlinear growth functions (logistic, Gompertz, and Richards) and 3 polynomial functions (linear, second-order, and third-order) were applied. Parameters of the models were estimated by the least squares procedure. The fit of growth curves to experimental data was assessed using R(2). A t-test was used to identify significant differences in the goodness of fit of the model to the different data sets (breeder manual, R6, and R7). The third-order polynomial gave the best fit to the Ross 308 parent broiler BW data, with R(2) ranging from 0.992 to 0.998. Among the nonlinear growth functions, the Richards model gave the best fit to the data, with R(2) ranging from 0.992 to 0.995. The advantage of second- and higher-order polynomial models is that they can be linearized and their parameters estimated by linear regression.

Growth characteristics of commercial broiler and native chickens as predicted by different growth functions

“…In agreement with this finding, the superiority of the Richards function, for its ability to function the growth curve of broiler chickens (male and female) and Ross 308 broiler parent flocks has been reported by other researchers (Darmani Kuhi et al, 2003;Tompić et al, 2011).…”

Adjustment of growth models in broiler chickens

“…Tompić et al (2011) obtained the best adjustments using the Richards and Gompertz growth models in broilers; Yang et al (2006) reported the von Bertalanffy model as the most accurate in Jinghai Yellow chicken; and Eleroğlu et al (2014) had concluded that the Logistic model the best fit in growth of slow performance chickens. However, despite the variety of existing growth models, one of the most recommended ones has been the Gompertz model in its traditional form (Freitas, 2005;Mazucheli et al, 2011;Drumond et al, 2013;Mohammed, 2015;Mota et al, 2015).…”

“…Richards (1) Gompertz, Logistic, and von Bertalanffy were adapted from Freitas (2005); while Richards was adapted from Tompić et al (2011). A, asymptotic final bodyweight; B, integration constant; K, maturity rate; M, (-1/n), i.e., the parameter that gives the curve its form; and, the residue in time t.…”

The growth of local white muscovy growth during starter and grower period

“…It is an important characteristic that describe the genetic potential of an individual. Growth can be defined as the development of body size per time unit or also called as growth rate (Tompić et al 2011). Based on the rate, the growth is divided into two phases: acceleration and retardation phases.…”