Determination of growth functions of indigenous and crossbred goats in Laos

ObjectiveThe present study was aimed at estimating of growth curves of the indigenous goat(Lat)and the Fl crossbred(Bach Thao×Lat)goat in Laos.MethodTwo surveys were carried out during the period 2009-2010 to conect data on live weight (W)as a function of age of the goats.Data on live weight of goats were first subjected to analysis of variance (ANOVA)to determine the significance of effects of genotype,sex and age on live weight.Both linear and nonlinear(Gompertz)growth models were used for each type of goats.ResultAs initial analyses of variance of the data showed that genotype and sex had highly significant influences on live weight,subsets of data were then used for drawing growth curves separately for female and male goats of each genotype.It was shown that for goats under 1 year of age,determination coefficients(R2)of the two regression models were very high (>9%)and almost similar to each other.However,with data for longer periods of age,Gompertz growth models were better fitted(higher R2)than the linear models(lower R2).The developed Gompertz growth models showed the mature weights of the female and the male to be 23.93 and 29.93 kg for Lat goats,32.66 and 37.69 kg for the F1 crossbred goats,respectively.ConclusionIt is concluded that nonlinear Gompertz growth models are suitable to estimate live weight as a function of age for both the indigenous and the F1 crossbred goats in Laos.