Abstract: The correlation among the daily feed intake,daily weight gain and feed to gain ratio (F/G) of Duroc boars in different body weight ranges were analyzied to evaluate the effectiveness of using higher initial weights to determine the growth and F/G of Duroc boars,to analysis the correlation between F/G in different body weight stages and whole process F/G of Duroc boars,to establish the regression equation between F/G in different body weight stages and whole process F/G,and to increase the annual measurement quantity of the measuring station and improve its utilization rate.The data of daily gain,daily feed intake and F/G of 119 Duroc boars during 30-110 kg were measured by using 8 Osborn feed intake recording equipments.The correlation between F/G at different weight stages and F/G at whole stages was analyzed,and the regression equation was established with the F/G at the whole stages.The results showed that the daily feed intake,daily gain and F/G of Duroc boars were all increased during the period of 30-110 kg,and there was an inflection point at 90 kg during the growing period,and they were all decreased after that.There was a certain correlation between the F/G at different weight stages and the F/G at the whole stages,in which the determination coefficient of the regression equation Y=0.316+0.873X₁ (X₁ was F/G of 40-90 kg) was 0.76.The correction accuracy of regression equations was high,and the F/G of 30-110 kg could be predicted by measuring the F/G of 40-90 kg.Using this coefficient,the time of F/G measurement could be shorten,and it also provide reference for more accurate calculation of F/G,and at the same time effectively improved the utilization rate of the pig breeding station.

Key words: Duroc boars; feed to gain ratio (F/G); daily gain; daily intake