Effect of persistency on milk yield under organised farm management condition

The evaluation of 255 Tharparkar cows having 887 records spread over a peri od of 15 years and 9 parities were done for production and reproduction tra its by using least-squares analysis. The overall mean of persistency was 0. 71 +/- 0.006. Season of calving and period x season interaction were signif icant (P<0.01) on persistency whereas, the effect of parity was non signifi cant. The effect of peak yield (as co-variable) was significant on persiste ncy and that of calving interval as nonsignificant on this trait. The pheno typic correlations of persistency with mi Ik yield and lactation length wer e positive and significant while they were negative and significant with pe ak yield, wet average and total digestible nutrients intake.