Growth curves of chickens with different type of performance

Abstract

Summary A comparative analysis of chicken growth curves (n = 328) of White Cornish, Orpington, New Hampshire breeds and two lines of White Leghorn was based on the Richards function parameters. The accuracy of curve fit was expressed by percentage deviations of the observed and estimated weights in individual points of the curve and for a standardized period of 24 weeks. The greatest deviations were observed at the beginning of the growth period. The breeds differed distinctly in the parameters of the growth curve concerning live weights and the rate of gains, i. e. in the asymptotic final weight (A), the weight at inflection point (y*) and average and maximal rate of growth (v and v*). Significant differences were recorded also in the length of the autoacceleration phase of growth (t*). The shape of average breed growth curves approximated at most the Gompertz type of growth (n → 0, y*/A ≐ 0.368), but high individual variability was established (− 0.4 ≤ n ≤ 1.0, 0.279 ≤ y*/A ≤ 0.500) within the investigated set of individuals. In the present study relationships among individual parameters of the Richards function are considered. High intragroup phenotypic correlations among the shape parameter n and the k parameter characterizing the rate of maturing (rp = 0.89 up to 0.97), n and A(rp = −0.26 up to −0.82), and k and A (rp = −0.44 up to −0.87) are the expression of functional relations among the parameters. Résumé Les courbes de croissance des poussins de différent types de rendement L'analyse comparative des courbes de croissance des poussins (n = 328) des races White Cornish, Orpington, New Hampshire et de deux lignées White Leghorn a été effectuée sur la base des paramètres de la fonction de Richards. La précision de la «curve fit» a été déterminée à l'aide des déviations de pour cent du poids réel et évalué dans les différents points de la courbes et pour une période standarde de 24 semaines. Les déviations les plus grandes ont été enregistrées au début de la période de croissance. Les races différaient réciproquement sur les paramètres de la fonction de croissance concernant le poids vif ainsi que la vitesse de l'obtention des gains de poids, c'est à dire dans le poids final asymptotique (A), sur le poids au moment de l'obtention du point d'inflexion (y*) et sur la vitesse moyenne et maximale de croissance (v et v*). Les différences significatives ont pu être trouvées dans la durée de la phase de croissance d'autoaccélération (t*). La forme des courbes de croissance ressemblait le plus au type de croissance de Gompertz (n → 0, y*/A ≐ 0.368), mais dans le cadre du groupe contrôlé d'individus a pu être trouvée une haute variabilité individuelle (−0.4 ≤ n ≤ 1.0, 0.279 ≤ y*/A ≤ 0.500). Le présent travail traite des dépendances réciproques entre les paramètres de la fonction de Richards. Les hautes corrélations phénotypiques au sein des groupes entre la paramètre de forme n et celui k qui caractérise la vitesse de croissance (rp = 0.89–0.97), n et A (rp = −0.26‐−0.82) et k et A (rp = −0.44‐−0.87) expriment la rel...

Modelling Growth Curves in a Nondescript Italian Chicken Breed: an Opportunity to Improve Genetic and Feeding Strategies

“…The range of t i values estimated in the present investigation varies from 12.046 to 13.414 weeks of age being similar to as reported by Eleroğlu et al (2014), by Osei-Amponsah et al (2014) in Ghanaian local chickens and by Rizzi et al (2013) in Italian local chicken populations and Yang et al (2006) in Jinghai yellow chickens. However, most of the available literature reports a very low age at inflection point, irrespective of the growth model fitted due to the fast growing pattern frequently observed in chickens (Knížetová et al, 1985;Goliomytis et al, 2003;Santos et al, 2005;Sakomura et al, 2011). Male chickens showed higher values than females in terms of W i and this result was found to be in agreement with findings reported by other authors (Santos et al, 2005;Rizzi et al, 2013;Eleroğlu et al, 2014).…”

The use of performance test parameters for selection of gilts before their placement into breeding

“…25 kg) until they reached the average live weight of 127 kg. The growth curves, described by Richards (1959), were simulated according to Nýdl and Tichý (1989) whereas their parameters and characteristics were interpreted in accordance with Knížetová et al (1985).…”

“…Growth analyses were reviewed by Robison (1976). Fitzhugh (1976) and Kníže and Hyánek (1981) examined the growth of farm animals by means of growth curves. Knížetová (1994) studied relationships between the shape of growth curve, feed conversion and carcass quality.…”

“…25 kg) until they reached the average live weight of 127 kg. The growth curves, described by Richards (1959), were simulated according to Nýdl and Tichý (1989) whereas their parameters and characteristics were interpreted in accordance with Knížetová et al (1985).A day before slaughter the gilts were measured with ultrasonic instruments SM-100 and PI-105 according to the methodology for determination of PT parameters. A modification of the given methodology was that for the purposes of carcass analysis of the cold right side of pork the parameters of backfat thickness (bt 1 in mm), backfat thickness and depth of MllT (bt 2 and MllT in mm) were measured at a distance of 70 mm to the right laterally from the central line.…”

Desempenho, crescimento, qualidade do ovo, composição corporal e características reprodutivas e ósseas de poedeiras submetidas a diferentes programas nutricionais

“…O crescimento da ave pode ser discutido, de forma simples, como uma função do peso corporal relacionado à idade expressa pela função: W = f(t), onde W = peso e t = tempo. Entretanto, Knízetová et al, (1991) Knízetová et al (1983Knízetová et al ( , 1985Knízetová et al ( , 1991.…”