Maternal nutrient intake during early- and mid-gestation can alter fetal growth and development with long-term consequences on the postnatal productivity and health of offspring. The aim of this study was to investigate the effects of maternal nutrition level during mid-gestation on postnatal growth rate, carcass composition, muscle fibre characteristics and meat quality in lambs. Ewes were fed from Days 30 to 80 of gestation as follows: 100% (control group, C), 50% (undernutrition, UN) or 175% (overnutrition, ON) of their daily requirement. During the rest of the gestation, the ewes in all groups were fed 100% of their daily requirements. Birth and weaning (at Day 90) weights of lambs born to ewes in nutritional groups were similar, but slaughter weights (at Day 150) and daily weight gain during finishing period of lambs born to the UN group were lower (P < 0.05). Similarly, a decrease in weights of semitendinosus (ST), semimembranosus and gastrocnemius muscles was observed in the lambs born to the UN group (P < 0.05). Lambs born to the ON group had a higher (P < 0.05) concentration of DNA in longissimus dorsi (LD) and ST muscles than UN groups, but they had a lower (P < 0.05) total protein and other proteins concentrations in LD and ST muscles than those to C and UN groups. Protein to DNA ratio in LD and ST muscles of lambs born to ON group were lower than those to C and UN groups (P < 0.05). However, lambs born to the ON group had a higher number of Type IIA and IIB muscle fibres in ST muscles but not in LD muscles than those in the C and UN groups (P < 0.05). Additionally an increase in the number of fibres/mm2 muscle area in lambs born to the ON group was observed in LD and ST muscles (P < 0.05). There were no significant differences between treatment groups in terms of meat quality parameters studied. This study confirms that maternal nutrition level during mid-gestation alters the postnatal growth and muscle fibre development of lambs.

The aim of this study was to determine growth performance, carcass and meat quality of Karayaka female lambs born in different seasons. Winter born (breeding season; n=15) and autumn born (out of the breeding season; n=15) singleton female lambs were used in the study. Birth and slaughter weights of lambs in both groups were similar, but the weaning weight of the autumn born lambs was higher (P<0.05). The autumn born lambs had lower carcass yield, lung, spleen and gastrocnemious muscle weights (P<0.05), but higher liver, kidney, empty reticulo-rumen, empty small intestine, internal fat, suprarenal fat weights and a higher fat thickness over the longissimus dorsi muscle (P<0.05). Additionally, the winter born lambs had higher cooking loss, drip loss and shear force values (P<0.05), but lower dry matter and intramuscular fat (P<0.05) in longissimus dorsi and semitendinosus muscles. There were significant differences between both groups in terms of meat colour characteristics (P<0.05) except b* values for longissimus dorsi at 1 h and for semitendinosus at 24 h. The results suggest that Karayaka female lambs born in winter and autumn seasons have different meat quality parameters and growth patterns at pre-and post-weaning.