Winter And Fall Lambing Performance Of Cross bred Ewes Of Finnsheep, Dorset, Rambouillet and White Face Western Breeding When Mated To Purebred Or Crossbred Rams

Reproductive performance of four, five and six-year old crossbred ewes representing six combinations ofFinnsheep (F), Dorset (D), Rambouillet (R), and White Face Western (WFW) breeding were evaluated when lambing in the winter (February-March, 1977) and in the fall (October-November, 1977). The six breed combinations represented were 3fsF, 5fsWFW; %F, 1f2D, %R; %F, %D, 1f2R; %F, %R; 1f2D, 1f2R; and %D, %R. Breeding effectiveness of purebred and crossbred rams of Hampshire and Suffolk breeding was also compared when mated to these ewes. Results of the winter lambing were more favorable than that of fall lambing with the entire flock averaging 1.8 lambs born per ewe exposed for winter and .53 lambs born per ewe exposed for the fall. Ewes of 3fsF, 5fsWFW breeding had a higher number (2.32) of lambs born per ewe exposed when lambing in the fall. They were followed by ewes of1f2D, 1f2R breeding (1.81), ewes of % Finnsheep breeding (1.74) and %D, %R breeding were lowest (1.56). When lambing in the fall ewes of 1f2D, IhR breeding had a higher number (.69) oflambs born per ewe exposed in face of a generally disappointing lamb crop. Ewes of %D, %R breeding followed with .56; ewes of 3fsF, 5fsWFW breeding had .46 and the average of the three % Finnsheep breeding groups was .46 also. Comparing September-October, 1976 and May-June, 1977 matings, reproductive performance of ewes when mated to either crossbred or purebred rams in September-October was virtually the same whether measured by percent ewes lambing, lambs born per ewe lambing or lambs born per ewe exposed. For May-June mating, at least 3 out of 4 crossbred yearling rams used outperformed purebreds in getting more ewes settled, in lambs born per ewe lambing, and in lambs born per ewe exposed.