Abstract. The aim of the study was to evaluate the growth, body and ultrasonic
measurements and some carcass traits of purebred Ramlıç, Texel and
crossbred (87.5 % Ramlıç and 12.5 % Texel) lambs in a marker-assisted introgression (MAI) project. The effects of some environmental
factors such as genotype, sex, birth type, dam age, weaning age, and birth
weight on growth, ultrasound measurements, and carcass traits were
significant (P<0.05). There were no significant differences
between pure Ramlıç and its myostatin carrier (+/-) and non-carrier
(-/-) second backcrosses (BC2) for birth weight, daily live weight
gain, and weaning weight. The BC2 genotype (+/-) was statistically
caught up with pure Ramlıç for wither height, body length, and rump
width. Differences in the longissimus muscle depth indicated that the
BC2 (+/-) genotypes tended to be better for both pure Ramlıç
and Texel lambs. Texel lambs were superior to Ramlıç in the aspect of
some carcass characteristics such as leg length, cold right-half carcass
weight, foreleg weight in the left-half carcass, and muscle weight in the
left leg. BC2 (+/-) lambs were in the middle of both breeds
for the traits. BC2 lambs carrying myostatin did not vary from Ramlıç morphologically. The new type of Ramlıç was also closer to Texel
in the aspect of carcass characteristics. In this connection, improvement of
indigenous breeds could be achieved by MAI without changing the essential
characteristics. For the summary, please visit http://www.mustafatekerli.com (last access: 14 June 2022).