The primary objective of the study was to determine the optimum length of service period that can maximize the production across the adjacent lactations and life time yield. Performance records of Karan Fries (KF) cow which were maintained at Livestock Research Centre (NDRI), with respect to service period spread over a period of 15 years (1998-2012) were collected for the study. Data of 681 KF cows were analysed by Least Square Technique to examine the effect of non-genetic factors on service period. Season of calving was classified into fourth seasons (i.e. winter, summer, rainy and autumn), period of birth into five periods (i.e. I-V) and parity into six (i.e. I-VI) respectively. For optimization of service period with regard to milk productivity, analysis was carried out by class interval method. Service period was classified into ninth (1-9) classes, ranging from Ë‚ 51 to >185 days. The overall least square mean of service period was 133.66 ± 3.89 days. Effect of period of birth and parity was significant (PË‚0.05) on service period, while season of calving was not significant on service period. The optimum level of service period was obtained at 52-70 days. From the study, it can be concluded that this service period length is suitable for maximising the production in the subsequent lactation.
Economic trait, Karan Fries, Non-genetic factors, Optimisation, Service Period