title: Genetic trend for growth and wool performance in a closed flock of Bharat Merino sheep at sub temperate region of Kodai hills, Tamil Nadu.
abstract: OBJECTIVE
  The study was conducted at Southern Regional Research Center, ICAR-Central Sheep and Wool Research Institute (CSWRI), Mannavanur, Kodaikanal, Tamil Nadu to estimate genetic trends for birth weight (BWT), weaning weight (3WT), 6 months weight (6WT), and greasy fleece weight (GFY) in a Bharat Merino (BM) flock, where selection was practiced for 6WT and GFY.
  
  
  METHODS
  The data for this study represents a total of 1652 BM lambs; progeny of 144 sires spread over 15 years starting from 2000 to 2014, obtained from the BM flock of ICAR-SRRC (CSWRI), Mannavanur, Kodaikanal, Tamil Nadu, India. The genetic trends were calculated by regression of average predicted breeding values using software WOMBAT for the traits BWT, 3WT, 6WT and GFY versus the animal's birth year.
  
  
  RESULTS
  The least square means were 3.28±0.02 kg, 19.08±0.23 kg, 25.00±0.35 kg and 2.13±0.07 kg for BWT, 3WT, 6WT and GFY, respectively. Genetic trends were positive and highly significant (p<0.01) for BWT, while the values for 3WT, 6WT and GFY though positive, were not significant. The estimates of genetic trends in BWT, 3WT, 6WT and GFY were 5 g, 0.8 g, 7 g and 0.3 g/year gain and the fit of the regression shows 55%, 22%, 42% and 12% coefficient of determination with the regressed value, respectively. In this study, estimated mean predicted breeding value (kg) in BWT and 3WT, 6WT and GFY were 0.067, 0.008, 0.036 and -0.003, respectively.
  
  
  CONCLUSIONS
  Estimates of genetic trends indicated that there was a positive genetic improvement in all studied traits and selection would be effective for the improvement of body weight traits and GFY of BM sheep.
authors.affiliation: Southern Regional Research Centre, ICAR-Central Sheep and Wool Research Institute, Mannavanur, Kodaikanal, Tamil Nadu, India.
authors.forename: P K
authors.initials: PK
authors.lastname: Mallick
authors.affiliation: Southern Regional Research Centre, ICAR-Central Sheep and Wool Research Institute, Mannavanur, Kodaikanal, Tamil Nadu, India.
authors.forename: S M K
authors.initials: SM
authors.lastname: Thirumaran
authors.affiliation: Southern Regional Research Centre, ICAR-Central Sheep and Wool Research Institute, Mannavanur, Kodaikanal, Tamil Nadu, India.
authors.forename: R
authors.initials: R
authors.lastname: Pourouchottamane
authors.affiliation: Southern Regional Research Centre, ICAR-Central Sheep and Wool Research Institute, Mannavanur, Kodaikanal, Tamil Nadu, India.
authors.forename: S
authors.initials: S
authors.lastname: Rajapandi
authors.affiliation: Post Graduate Research Institute in Animal Sciences, Kattupakkam, Kancheepuram, Tamil Nadu, India.
authors.forename: R
authors.initials: R
authors.lastname: Venkataramanan
authors.affiliation: Southern Regional Research Centre, ICAR-Central Sheep and Wool Research Institute, Mannavanur, Kodaikanal, Tamil Nadu, India.
authors.forename: G
authors.initials: G
authors.lastname: Nagarajan
authors.affiliation: Southern Regional Research Centre, ICAR-Central Sheep and Wool Research Institute, Mannavanur, Kodaikanal, Tamil Nadu, India.
authors.forename: G
authors.initials: G
authors.lastname: Murali
authors.affiliation: Southern Regional Research Centre, ICAR-Central Sheep and Wool Research Institute, Mannavanur, Kodaikanal, Tamil Nadu, India.
authors.forename: A S
authors.initials: AS
authors.lastname: Rajendiran
keywords: Bharat Merino sheep; breeding value; genetic trend; regression