FACTORS AFFECTING ON AGE AT FIRST CALVING IN CROSSBRED CATTLE MAINTAINED AT LES QADIRABAD DISTRICT SAHIWAL

The data on age at first calving for 539 records of crossbred cows of differentfilial/genetic groups were considered for the present investigation. These crossbreds belonged to eightfilial/genetic groups (F1, F2, F3, F4, F5, F6, F7 and F8) maintained at Livestock Experiment StationQadirabad District Sahiwal from 1991 to 2014 (24 years). The duration of 24 year was divided into 6periods (P1, P2, P3, P4, P5 and P6) of four years each. Each year was further divided into threeseasons as winter (November-February), summer (March- June) and spring (July-October) on the basisof geo-climatic conditions prevailing in the region. The overall population mean of age at first calvingwas determined 1261.88±9.934 days. The analysis of variance revealed significant effect of period ofcalving on age at first calving. The finding of this study shows that age at first calving was subjected tonon-genetic factor. Effect of season of calving on age at first calving was non- significant whichindicate breed characteristic to adaptation with environment. Meanwhile effect of filial/genetic groupwas significant on age at first calving. Therefore, from the result of this investigation it can bedetermined that improving the feeding, health and other husbandry practices are essential to enhancethe performance trait of this herd.