www.tjprc.org editor@tjprc.org GENETIC EVALUATION OF CROSSBRED CATTLE FOR REPRODUCTION TRAITS SUNIL KUMAR, D. S. DALAL, B. L. PANDER, C. S. PATIL & RAKESH VERMA Department of Animal Genetics and Breeding, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar-, India ABSTRACT The data on 333 crossbred cows maintained in the Department of Animal Genetics and Breeding, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana over a period of 24 years from 1991 to 2014 were analyzed for studying the effect of genetic factor i.e. sire group and non genetic factors i.e. period of calving, season of calving and milk yield group and to estimate genetic and phenotypic parameters for reproduction traits. The traits studied were age at first calving (AFC), first service period (FSP), first calving interval (FCI), number of services per first conception (NS/FCON), waiting period (WP) and daughter pregnancy rate (DPR42, DPR63). The least squares mean for AFC, FSP, FCI, NS/FCON, WP, DPR42 and DPR63 were observed as 1242.75±16.46 days, 148.46±6.99 days, 429.08±7.08 days, 1.90±0.12, 100.85±4.20 days, 0.27±0.02 and 0.35±0.04, respectively. The period of calving had significant effect on AFC, while season of calving had significant effect on FSP and FCI. The milk yield group had significant effect on all traits. Heritability estimates of these traits were low to moderate. Genetic and phenotypic correlations among FSP, FCI, WP and NS/FCON were found to be moderate to high positive. DPR showed moderate and negative genetic correlation with FSP, FCI, WP and NS/FCON whereas; corresponding phenotypic correlations with these traits were significant negative. KEYWORDS: Correlation, Crossbred Cattle, Daughter Pregnancy Rate, Heritability & Reproduction Traits Received: Oct 13, 2017; Accepted: Nov 03, 2017; Published: Nov 15, 2017; Paper Id.: IJASRDEC201729 INTRODUCTION The economic worth of milch animals is primarily determined by their productive performances. Hence in selection process, generally more emphasis is given to production traits. In past decades successful selection on milk production traits in dairy cattle has led to decline in female fertility due to unfavorable, correlated selection response (Jorjani, 2006). Thus, incorporation of fertility in selection decisions seems desirable. Improvement of fertility in lactating animals has become the key objective for selection programs in recent years in most countries. Many countries have used Daughter Pregnancy Rate and Service period for genetic evaluation of their dairy animals. It is essential to have knowledge of genetic and non-genetic factors influencing the performance traits to obtain unbiased estimates of genetic parameters and for developing a suitable selection criterion. The accuracy of selection and genetic correlation between performance traits contribute much to the success of any breeding programme. Therefore, the present investigation was carried out to estimate genetic and phenotypic parameters of different first lactation reproduction traits and to study the effect of genetic and non-genetic factors on these traits. Original Article International Journal of Agricultural Science and Research (IJASR) ISSN (P): 2250-0057; ISSN (E): 2321-0087 Vol. 7, Issue 6, Dec 2017, 217-224 © TJPRC Pvt. Ltd