Phenotypic and genetic parameters of growth traits in Rahmani and Romanov sheep and crossbreds

A. Khattab1, Sunday Peters2,*, Adeyemi Adenaike3, Abdel Aziz Sallam4, Mahasan Atya1, Heba Ahmed4
Author Information & Copyright
1Department of Animal Production, Faculty of Agriculture, Tanta University, Central Delta 37512, Egypt.
2Department of Animal Science, Berry College, Georgia 30149, United States.
3Department of Animal Breeding and Genetics, Federal University of Agriculture,, Abeokuta 2234, Nigeria.
4Animal production Research Institute, Ministry of Agriculture, Dokki, Cairo 12126, Egypt.
*Corresponding Author: Sunday O. Peters, Department of Animal Science, Berry College, Georgia 30149, United States. E-mail:

© Copyright 2021 Korean Society of Animal Science and Technology. This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Received: May 24, 2021; Revised: Jul 21, 2021; Accepted: Oct 19, 2021

Published Online: Oct 25, 2021


Data of  651 lambs (68 Romanov, 49 Rahmani, 151 (♀1/2 Rahmani X ♂1/2 Romanov) and 383 (♀3/4 Rahmani and 1/4♂ Romanov)) were collected from Mehalet Mousa Farm, belonging to Animal Production Research Institute from the period of 2009 to 2016 to estimate phenotypic and genetic parameters. The traits studied were birth weight (BW), body weight at four week (BW4), body weight at eight weeks (BW8) and body weight at twelve weeks (BW12) or weaning weight. Least squares analysis of variance shows significance of the effects of breed groups, gender of lambs, birth type; month of birth and year of birth on all traits studied.  Rahmani lambs had heavier BW, BW4, BW8 and BW12 while Romanov lambs had the lowest ones. The first generation (♀1/2 Rhamani X ♂1/2 Romanov) had heavier body weights than Romanov and the second generation (♀3/4 Rahmani X ♂1/4 Roamnov). Gender of lambs had highly significant effect on body weights. Males were significantly (P<0.01) heavier than females for all traits studied. Least square means of BW, BW4, BW8 and BW12 for single lambs were 2.69, 10.43, 13.53 and 16.10kg, respectively. Least square means of BW, BW4, BW8 and BW12 for twin lambs were 2.50, 9.37, 12.5 and 15.16kg, respectively, while least square means of  BW, BW4, BW8 and BW12  for triple lambs were 2.09, 7.86, 10.83 and 13.67kg, respectively. Estimates of direct heritability measured by single trait animal model were 0.14, 0.23, 0.25 and 0.26 for BW, BW4, BW8 and BW12, respectively, and the corresponding measured by multi trait animal model were 0.17, 0.24, 0.32 and 0.36 for the same traits, respectively. All genetic and phenotypic correlations among different traits studied are positive and significant.

Keywords: Phenotypic; genetic; Rahmani; Romanov; Breed