title: Genetic analysis of reproductive performance of Frieswal cattle at Military Farm, Ambala.
abstract: OBJECTIVE
  This study was carried out to investigate the genetic analysis of reproductive performance of Frieswal cattle at Military Farm, Ambala.
  
  
  METHODS
  A total number of 3005 lactation records of 1147 Frieswal cows over a period of 15 years extending from 1993 to 2007 were used to study at Military Dairy Farm, Ambala. The study period was divided into 5 period of 3 years each. The average performances of reproduction traits, effect of genetic and non-genetic factors were analyzed, and estimation of genetic and phenotypic parameters of reproduction traits was undertaken.
  
  
  RESULTS
  The age at first calving (AFC) differed significantly across the periods of calving. The AFC was lowest during the third period (1999-2001) and longest in the first period (1993-95). The effect of season and period of calving, lactation order and regression of AFC on dry period, calving interval and service period was highly significant. The effect of sire was non-significant. The heritability estimates were low for almost all the traits under study. The service period had a high genetic correlation with dry period and calving interval. The dry period also found to have a low genetic correlation with calving interval in Frieswal cows. Service period had a high phenotypic correlation with dry period and very high with a calving interval. The phenotypic correlation between the dry period and calving interval was recognized high.
  
  
  CONCLUSIONS
  Low heritability estimate for the reproduction traits indicates that there is a very little additive genetic variance in these traits, and individual selection will not be helpful for improving them. Improvement may be brought through better feeding and management of cows by reducing the environmental variability.
authors.affiliation: Department of Animal Husbandry, College of Veterinary and Animal Sciences, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut, Uttar Pradesh, India.
authors.forename: Jagdeep
authors.initials: J
authors.lastname: Kumar
authors.affiliation: Department of Animal Husbandry, College of Veterinary and Animal Sciences, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut, Uttar Pradesh, India.
authors.forename: Y P
authors.initials: YP
authors.lastname: Singh
authors.affiliation: Dairy Cattle Breeding Division, Central Institute for Research on Cattle, Meerut, Uttar Pradesh, India.
authors.forename: Sushil
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Department of Animal Husbandry, College of Veterinary and Animal Sciences, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut, Uttar Pradesh, India.
authors.forename: Rajbir
authors.initials: R
authors.lastname: Singh
authors.affiliation: Dairy Cattle Breeding Division, Central Institute for Research on Cattle, Meerut, Uttar Pradesh, India.
authors.forename: Ravinder
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Department of Animal Husbandry, College of Veterinary and Animal Sciences, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut, Uttar Pradesh, India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
keywords: Frieswal cattle; age at first calving; non-genetics factors; service period