Vol. 6, Issue 5, Part A (2021)

Author(s): Kefale Getahun, Zenebech Lemma and Nibo Benebru

Abstract: Data collected from Jersey herd in the central highland environment of Ethiopia was used to estimate genetic parameter and genetic trend analysis for reproductive/fertility traits. Totally, 11,933 Jersey reproductive records recorded during the last 30 years were used for analysis. Traits studied were NSC (number of service per conception), DO (days open), CI (calving interval), AFC (age at first calving) and AFS (age at first service). Genetic and phenotypic parameters (heritability, repeatability, genetic and phenotypic correlation and estimated breeding values of individual animal) were estimated by using WOMBAT software package, version (2020) fitting a multi trait animal model. Genetic and phenotypic trends were calculated by regression of average estimated breeding values/phenotypic values of each trait on birth years. The estimated heritability for NSC, DO, CI, AFC and AFS were 0.01, 0.08, 0.04, 0.09 and 0.08, respectively while the corresponding repeatability values were 0.01, 0.11 and 0.14, respectively without the estimated values of AFC and AFS. Genetic correlations were all positive and in the range from 0.11 between DO and AFC to 0.99 between DO and CI. Phenotypic correlations were also positive and ranges from 0.16 (AFS-CI) to 0.98 (AFC-AFS). Genetic trend analysis based on birth years for NSC, DO, CI, AFC and AFS were in the favorable direction and found to be -0.002, -0.82 day, -0.6 day, -0.002 month and -0.002 month, respectively whereas phenotypic trends were -0.05, 0.93 day, 0.81 day, 3.2 months and 2.4 months, respectively which are unfavorable direction and undesirable for most traits. As monitored in the present study, the reproductive/fertility performance of Jersey cows in the central highland of Ethiopia was somewhat based on genetic effects but larger undesirable environmental components for the total phenotypic value.

DOI: 10.22271/veterinary.2021.v6.i5a.374