Journal of Biological Sciences1727-30481812-5719Asian Network for Scientific Information10.3923/jbs.2007.1347.1353ChalhAbdellah Mohamed El Gazzah DjemaliMnaouer ChalbiNoureddine 8200778Growth data recorded on 10244 Noire de Thibar lambs born along five years and raised in ten flocks in North-Western region of Tunisia were used to carry out this study. The analysis of variance has shown that herd, sex-type of birth and herd by date of birth interaction had highly significant effects on the lamb growth. Males born single were heavier and grew faster than the other sex-type of birth categories. However, twin or multiple males were less heavy than females born single. Age of dam had a significant effect only from birth to seventy days. The birth date, as well as the interaction among herd and sex-type of birth affected significantly all studied traits except the average daily gain between 70 and 90 days. Multiplicative adjustment coefficients were computed for sex-type of birth and age of dam factors. Heritability of each growth trait was estimated by an adjusted regression dam-offspring method. Genetic and phenotypic correlations between the traits were also estimated. Such parameters should be essential information for developing genetic evaluation tools and/or elaborating genetic improvement programs, especially, if we consider that the present selection practice remains empirically based on a biased average daily gain between 10 and 30 days.]]>Abegaz, S., E. Negussie, G. Duguma and J.E.O. Rege,20021193545Al-Shorepy, S.A.,2001137365371Benyi, K., D. Norris, N. Karbo and K.A. Kgomo,200638547554Blackwell, R.L. and C.R. Henderson,195514831842Boujenane, I. and M. Kerfal,199050173178Boujenane, I. and A. Mharchi,1992121522Ch'ang, T.S. and A.L. Rea,197021115129Djemali, M., R. Aloulou and M. Ben-Sassi,1994124147Djemali, M. and G. Alhadrami,19971997pp: 171174El-Tawil, E.A., L.N. Hazel, G.M. Sidwell and C.E. Terrill,197031823827Falconer, D.S.,19812nd Edn.,Gbangboche, A.B., A.K.I. Youssao, M. Senon, M. Adamou-Ndiaye and A. Ahissou et al.,2006385564Gouhis, F.,19891989Hamada, M.K.O.,19761976Hassan, N. and S.M. Makuza,200518151157Inyangala, B.A.O., J.E.O. Rege and S. Itulya,19821982Katsaounis, N. and D. Zygoyarnis,1986162587592Khaldi, G., D. Boichard and L. Tchamitchian,198760518Mandal, A., K.P. Pant, D.K. Nandy, P.K. Rout and R. Roy,200335271284Martin, T.G., D.I. Sales, C. Smith and D. Nickolson,198030216269Mason, I.L.,19671967Mavrogenis, A.P., A. Louca and W.D. Robinson,198030271276Norgerg, E., P. Berg and J. Pedersen,200555123127Rochambeau, H.,1983335561SAS/STAT,19984th Edn., Vol. 1-2,Thakur, S.S. and B.C. Patnayak,1987Lasiurus sindicus) pastre.]]>57306309