Development of a suitable model for ascertaining the growth and egg production in quails
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Date
1991
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Department of Agricultural Statistics, College of Horticulture, Vellanikkara
Abstract
An investigation was carried out into the growth and egg production aspect of Japanese quails at the Kerala Agricultural University Poultry Farm, Mannuthy on 1st February, 1989 with the following objectives. 1. to find a suitable relationship between age and body weight. 2. to investigate the" trend of egg production in quails through suitable mathematical models. ,3. to study the impact of climate parameters (temperature, ; , humidity) on egg production in quails. The birds were reared under uniform feed formula and ^identical management practices (recommended by Kerala Agricul tural University Package of Practices). The investigation mainly depended on' data consisting of weekly body weights of -ii^-dividual birds, daily egg production of birds (beginning from age at sexual maturity) and daily climatological para meters (temperature and humidity) from beginning till the end of experiment of 30th September, 1989. Mathematical models such as linear, quadratic, exponential, .Von-Bertalanffy, modified exponential, logistic and Gompertz were fitted for the purpose using body weights of ) individual birds as well as average body weights over twelve weeks and the fitted models were compared using coefficient of 2 determination (r ) and standard error of estimate(s). Mathematical models such as linear, exponentialf parabolic exponential, inverse polynomial. Gamma function. Gamma-type functic^n, quadratic function, quadratic function in logari'thmic scale, quadratic-cum-log, emperical and linear hyperbolic functions were fitted for the development of suitable models for ascertaining egg production using total weekly, fortnightly egg production, hen housed and hen day egg production and fitted models were compared using Furnival index, r^ and s. Multiple linear regression equation was fitted using average weekly egg production per bird as dependent variable and weekly temperature and humidity as explanatory variable to study the impact of climatological parameters on egg production in quails. The investigation has the following, salient features. (i) The hatching weight of Japanese quails were 7.1369 g. (ii) The females weighed more than the males during the entire period of experiment and the body weights have shown an increasing trend. At the end of 12th week the average body weights of males and females were 157.6552 g and 179.2500 g respectively. (iii) Rao's method justified that initial body weights • had no significant effect on growth rate. • (iv) Gompertz curve = a exp [-b exp(-kt)'] was most , suitable for , ascertaining growth in quails on individual basis as well as on the basis of • average body weights over twelve weeks. (v) Average age at sexual maturity (females) was found to be approximately 10 weeks and on an average the eggs weighed 12.20 g. (vi) Quadratic function in logarithmic scale ; = a f b(logJ^) + c(log^)^ was most suitable , for ascertaining egg production in quails (weekly, , fortnightly, hen housed and hen day production • basis). (vii) Climatic parameters had significant impact on egg production in quails.
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Citation
TH-633