Bu araştırmada, Doğu Anadolu Tarımsal Araştırma Enstitüsü şartlarında yetiştirilen Esmer ve Siyah Alaca sığırların döl verim özellikleri incelenmiştir. Esmer ve Siyah Alacalarda, ortalama olarak sırasıyla damızlıkta kullanma yaşı 796.9±46.1 ve 664.3±34.2 gün, ilkine buzağılama yaşı 1083.4±44.8 ve 936.7±33.2 gün, servis periyodu 109.8±5.6 ve 119.9±6.6 gün, gebelik süresi 283.7±1.3 ve 279.3±1.5 gün, buzağılama aralığı 394.6±6.0 ve 402.4±7.1 gün olarak bulunmuştur. Irkın, damızlıkta kullanma yaşına etkisi önemli (P<0.05), servis periyodu ve buzağılama aralığına etkisi ise çok önemli (P<0.01) olduğu belirlenmiştir.

In this research, some reproductive performance traits of Brown Swiss and Holstein cattles reared in conditions of East Anatolia Research Institute were investigated. Terrestrial climate conditions prevail in where the study was conducted. The mean values in Brown Swiss and Holstein cattles were 796.9±46.1 and 664.3±34.2 days for first breeding age; 1083.4±44.8 and 936.7±33.2 days for first calving age; 109.8±5.6 and 119.9±6.6 days for service period; 283.7±1.3 and 279.3±1.5 days for gestation length; 394.6±6.0 and 402.4±7.1 days for calving interval, respectively. The effect of breed on first breeding age, first calving age and gestation length was found to be significant (P<0.05) and highly significant (P<0.01). The effect of years on service period, gestation length and calving interval were significant (P<0.05) and highly significant (P<0.01). The effect of season on gestation length was found significant (P<0.05). Service period and calving interval were affected by season (P<0.01)