Published online by Cambridge University Press: 27 March 2009
The improvement of milk production by the establishment of four specialized lines and subsequent within-line selection over a 7-year period under grazing conditions at Kraim station in mid-Syria is described. The specialized line showed a substantially higher total milk production amounting to a mean 25% superiority over the control line in 1979–81.
The heritability of total milk yield as estimated from paternal half sib analyses was 0·53 ± 0·169 for 2-year-old ewes and the genetic correlation of a single maximum daily yield record (+ 0·93) with total yield indicates the possibility of simplified selection procedures for this trait.
The effect of several other factors (for example, ewe age and season of lambing) on various aspects of lactation in Awassi ewes is reported.