Author/Authors :
SUHAIL, SYED MUHAMMAD NWFP Agricultural University - Faculty of Animal Husbandry Veterinary Sciences, Pakistan , AHMED, IJAZ NWFP Agricultural University - Faculty of Animal Husbandry Veterinary Sciences, Pakistan , HAFEEZ, ABDUL NWFP Agricultural University - Faculty of Animal Husbandry and Veterinary Sciences, Pakistan , AHMED, SOHAIL NWFP Agricultural University - Faculty of Animal Husbandry and Veterinary Sciences, Pakistan , JAN, DAWOOD NWFP Agricultural University - Faculty of Animal Husbandry Veterinary Sciences, Pakistan , KHAN, SARZAMIN NWFP Agricultural University - Department of Agricultural Economics, Pakistan , REHMAN, ALTAF-UR NWFP Agricultural University - Faculty of Animal Husbandry Veterinary Sciences, Pakistan
Abstract :
A part of the purebred Jersey cattle was shifted to Cattle Breeding and Dairy Farm Harichand in 1993, from an imported herd maintained at National Agricultural Center Islamabad during early eighties. The genetic analysis was carried out utilizing its records until 2003 in order to investigate the reproductive performance under subtropical environment. Age at first calving (AFC), calving interval (CI) and dry period (DP) were found to be 1010.73 ± 1.84, 487.31 ± 19.08 and 169.26 ± 16.45 days, respectively. The effect of year, sire and season of calving on various traits was also studied. Year had a significant (P 0.05) effect on AFC while sire and season of calving had not. The effect of sire, season and year of calving on CI and DP was non significant. Heritability estimates for AFC, CI and DP were found to be 0.4802 ± 0.3553; 0.1011 ± 0.1998; 0.1013 ± 0.2123, respectively. The findings suggested the lower limit of age at first calving of Jersey cows showed their better adaptation in the subtropical environment of NWFP. Distribution of cows regarding minimum range of the length of calving interval should be emphasized in selection programs as calving interval is the most crucial reproductive trait which could be minimized with careful detection of estrus and successful mating. More records on reproductive traits of half sibs should be included in the analysis in order to minimize standard errors associated with the parameters estimated.
