The Determination of Growth Curve Models in Malya Sheep from Weaning to Two Years of Age

Abstract

This research was carried out to determine the growth curve models for Malya ewes. Twenty sheep were fed ad-libitum with roughages from weaning to approximately 48 month of age. Each sheep was provided with 200 g concentrate feed (16% CP; 2500 kcal kg-1 metabolic energy) until the end of mating period and then 250 g from the end of mating period to the middle of gestation period. Towards the last month of pregnancy, the daily amount of concentrate feed was gradually increased to 500 g. Twenty sheep were weighed at 28 days intervals in 45 different control periods between weaning age through 2 years of age. The growth curve parameters, coefficients of determination (R2), mean square predicted errors (MSPE) and correlations between live weights and residuals (RESC) were determined for Linear, Quadratic, Cubic, Gompertz and Logistic models by using live weight data of Malya sheep. The highest R2 values, the lowest MSPE and RESC values, similarity between actual and estimated live weight values were used to evaluate the fitness of the growth curve models. R2 values of Linear, Quadratic, Cubic, Gompertz and Logistic model were determined as 83.13%, 91.04%, 92.04%, 91.55% and 91.22%, respectively, while MSPE values were 65.900, 34.657, 30.894, 32.956 and 34.101, respectively. Also, RESC values were found as 0.469, 0.287, 0.279, 0.299 and 0.333, respectively. These findings revealed that the best fit to the growth curves of Malya ewes was acquired with Cubic Model. However, all models can be accepted satisfactory to determine the growth in this period except for linear model. These results can be useful for farmers in defining proper breeding and feeding strategies.

Keywords

• büyüme eğrisi
• vücut ağırlığı
• malya koyunu
• matematik model
• doğrusal model
• doğrusal olmayan model
• malya sheep
• body weight
• growth curve