Pattern of growth in domestic fowl

Abstract

Under uniform feed formula and identical management practices, 30 Australorp (ALP) males, 26 (ALP) females, 25 white Leghorn(WL) males and 31 (WL) females, were reared for 24 weeks in Kerala Agricultural University Poultry Farm, Mannuthy to study their growth patterns. The initial mean body weights of chicks were 35g. for ALPmales, 34.4615g. for ALP females, 33.04g for WL males, 32.0645g. for WL females. Throughout the experiment males in each genetic group had a higher mean weight than females. A plateau on the body weight was reached by the end of 23 weeks in almost all birds, indicating that 24 weeks completely covered the growth period. By the end of the experiment the mean body weight was 1858g for ALP males, 1488.4615g. for ALP females, 1556.8g. for WL males, 1306.1290g for WL females. Though there was no significant difference between the groups at the end of the fourth week, significant differences between pairs were observed after 16 weeks. Exponential (y =aebx), Gompertz (y = abcx) and Logestic (105/y = a + bcx) curves were found to be suitable for fitting body weights for 24 weeks. The first two gave extremely good fit. Modified exponential was good only for data of twelve weeks. When growth rates for twenty four weeks were compared on the basis of the fitted curves for all birds the conclusion arrived at was the same for exponential and Gompertz curves. The rates of growth for ALP males, WL males, ALP females WL females and were in the descending order of magnitude; they were significantly different. Same was the inference obtained when Rao’s method of comparing rates of growth was adopted. The result obtained for comparing the rates of growth by fitting Exponential and Modified exponential for the body weights of birds for 12 weeks were similar. Both the curves gave very satisfactory fit to the data. The coefficient of correlation between the observed and expected body weights was nearly unity in almost all cases.