Performance Evaluation of First Lactation Reproductive Traits of Jersey Breed at Adea-Berga Dairy Research Farm

Performance evaluation for economically important first lactation reproductive traits is the bases for genetic evaluation, planning breeding programs, and selection for dairy cows. This study aimed to evaluate the performance of the first lactation reproductive traits of the Jersey breed at the Adea-Berga dairy research farm. The data collected from ۱۹۸۶ to ۲۰۲۰ from a herd maintained at Adea-Berga dairy research farm was used to evaluate performance for first lactation reproductive traits (age at first service (AFS), age at first calving (AFC), first calving interval (FCI), first days open (FDO), and first number of services per conception (FNSPC)). A general linear model procedure of the Statistical Analysis System (SAS, version ۹.۰) was used to analyse the first reproductive performance data. The result of the fixed-effect analysis revealed that the influence of year caused significant (p<۰.۰۰۰۱) variation in all first reproductive traits. The overall least squares mean (LSM±SE) for AFS, AFC, FCI, FDO, and FNSPC were ۲۳.۰۸±۰.۲۲ months, ۳۲.۷۰±۰.۱۹ months, ۴۶۶.۸۴±۱۵.۶۰ days, ۱۸۲.۲۵±۱۶.۳۴ days, and ۱.۶۷±۰.۱۲, respectively. In conclusion, the results of this paper suggest that the improvement of first lactation reproductive traits of the pure Jersey cattle population at Adea-Berga dairy research farm is possible through improving the level of feeding, breeding, and health management than through genetic selection.Keywords: first lactation, pure Jersey cows, reproductive traitsPerformance evaluation for economically important first lactation reproductive traits is the bases for genetic evaluation, planning breeding programs, and selection for dairy cows. This study aimed to evaluate the performance of the first lactation reproductive traits of the Jersey breed at the Adea-Berga dairy research farm. The data collected from ۱۹۸۶ to ۲۰۲۰ from a herd maintained at Adea-Berga dairy research farm was used to evaluate performance for first lactation reproductive traits (age at first service (AFS), age at first calving (AFC), first calving interval (FCI), first days open (FDO), and first number of services per conception (FNSPC)). A general linear model procedure of the Statistical Analysis System (SAS, version ۹.۰) was used to analyse the first reproductive performance data. The result of the fixed-effect analysis revealed that the influence of year caused significant (p<۰.۰۰۰۱) variation in all first reproductive traits. The overall least squares mean (LSM±SE) for AFS, AFC, FCI, FDO, and FNSPC were ۲۳.۰۸±۰.۲۲ months, ۳۲.۷۰±۰.۱۹ months, ۴۶۶.۸۴±۱۵.۶۰ days, ۱۸۲.۲۵±۱۶.۳۴ days, and ۱.۶۷±۰.۱۲, respectively. In conclusion, the results of this paper suggest that the improvement of first lactation reproductive traits of the pure Jersey cattle population at Adea-Berga dairy research farm is possible through improving the level of feeding, breeding, and health management than through genetic selection. Keywords: first lactation, pure Jersey cows, reproductive traits

Keywords:

First Lactation , Pure Jersey Cows , Reproductive Traits