Rate of Early Growth in Domestic Fowl

Brant, John

doi:10.3382/ps.0300343

Cited by 5 publications

(3 citation statements)

References 25 publications

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“…Brenner 1964) or exponential equations (e.g. Brant 1951) has the complementary disadvantage that the asymptotes of growth curves cannot be compared. The fitting of asymptotic equations to growth curves yields both kinds of information and has been applied to the growth of birds, for example by Taylor & Roberts (1961) and G. A.…”

Section: Intraspecific Variationmentioning

confidence: 99%

Patterns of Growth in Birds

Ricklefs

1968

Ibis

679

251

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Summary Parameters used to characterize the course of growth are described, and calculated growth parameters are presented for 105 species of birds of many taxonomic groups from a wide range of geographical localities. Growth parameters are found to exhibit as much as 20% variation within a species with respect to geographic locality and time of the nesting season. There is also considerable local variation, irrespective of season and locality, which is related to nutrition and perhaps to an inherited variability. The application of curve‐fitting as a method of analysing intraspecific variation is discussed briefly, and the importance of comparative growth studies is emphasized. Growth patterns are correlated with other parameters of the life‐history to evaluate the extent of diversity in the course of growth. Low rates of growth and prolonged growth periods occur primarily in species large for their families and in oceanic species. In most others, high rates of growth are maintained for longer periods of time. The shape of the growth curve is not related to the mode of development (i.e. whether precocial or altricial). Overall relative, or weight‐specific growth rates, as measured by the constants of fitted growth equations, are most highly correlated with the adult body size of the species, changing as the ‐0–278 power of adult body weight. Smaller variations in the rate of growth appear to be correlated with differences in nesting success; open‐nesting passerines grow faster than hole‐nesting species of a similar size. Growth rate is further correlated with brood size. Oceanic species with single egg clutches and tropical land‐birds with small clutches have low growth rates. The asymptote of the growth curve of the young (in relation to the adult weight) is related to the foraging behaviour of the adults. Aerial feeders generally have high asymptotes while those of ground feeding species are usually below adult weight. These differences are related to the need in the former for well‐developed flight at the time of fledging. The diversity of growth patterns is related to evolutionary trends which are the result of (1) selective forces acting at stages of the life‐history cycle other than development, (2) factors which affect the survival of offspring during the growth period, and (3) adjustments made to balance the energy budget of the family group. The last trend is discussed in detail in relation to the correlations found in the analysis. Two hypotheses are presented. Firstly, in species which cannot gather enough food to support even one young at a normal growth rate, the pace of development is reduced to decrease the energetic requirements of the young. Secondly, in species with small clutches, where adjustments to feeding capacities are not readily made by changing brood size, growth rate may be adjusted to accomplish this. The lack of critical energetic data to test these hypotheses is emphasized as a major deficiency in our understanding of the breeding biology of birds.

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Section: Intraspecific Variationmentioning

confidence: 99%

Patterns of Growth in Birds

Ricklefs

1968

Ibis

679

251

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“…The most extensively applied mathematical models, characterizing the whole course of growth including asymptotic final weight and inflection point parameters where the autoacceleration phase of growth passes into autoretardation phase, are monomolecular, logistic, Gompertz and Bertalanffy functions which are special cases of the generalized four‐parameter Richards function with variable inflection point position (R ichards 1959, E isen et al 1969, F itzhugh 1976, M c C arthy , B arker 1979 and others). Shorter growth periods can be expressed by simple functions, e. g. power (R oberts 1964, T anabe , S aeki 1964), exponential (B rody 1945, B rant 1951) or quadratic function (S usaki 1966). A critical analysis of various mathematical model applications to the growth of chickens was presented in the study of G rossman and B ohren (1982).…”

Section: Introductionmentioning

confidence: 99%

Growth curves of chickens with different type of performance

Knízetová

Hyánek

Hájková

et al. 1985

J Animal Breeding Genetics

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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...

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“…Goodman and Godfrey (195U) in a study of body weight of broilers, found that 11 percent of the variance in weight at 9 weeks of age was due to hatch effects. Brant (1951) reported that the differences in early growth between hatches were greater than the differences between the breeds and strains used.…”

Section: List 0? Tables (Continued)mentioning

confidence: 99%

Genetic and environmental effects on body measurements in broiler chickens

Merritt

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Rate of Early Growth in Domestic Fowl

Abstract: From a reasonably intensive review of the animal science literature, two general situations were noted. First, ample evidence suggests the more careful use of the term rate of growth, or growth rate(s); second, a new method is needed to analyze growth-in-time studies.

Cited by 5 publications

References 25 publications

Patterns of Growth in Birds

Patterns of Growth in Birds

Growth curves of chickens with different type of performance

Genetic and environmental effects on body measurements in broiler chickens

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