Bu çalışma, Konya Hayvancılık Merkez Araştırma Enstitüsü şartlarındaki Esmer ırk sığırların dölverimi özellikleri üzerine mevsimin etkisini incelemek amacıyla yapılmıştır. Araştırmanın materyalini, 1976-1985 yılları arasındaki 10 yıllık dönemde Enstitüde bulunan 637 baş Esmer ırk sığırın dölverimi ile ilgili kayıtları oluşturmuştur.Buzağılama aralığına ait ortalama değerler kış mevsiminde 390.1 gün, ilkbahar mevsiminde 355.1 gün yaz mevsiminde 413.9 gün ve sonbahar mevsiminde 384.9gün bulunmuştur. Mevsimlere göre buzağılama aralığı ortalamaları arasındaki farklılık önemsizdir. Gebelik süresine ait ortalamalar, ilkbahar mevsiminde 288.6 gün,yaz mevsiminde 284.9 gün,sonbahar mevsiminde 287.1 gün ve kış mevsiminde 287.8 gün olarak bulunmuş olup, ortalamalar arası farklılık önemli olmuştur (P<0.05). Servis periyoduna ait genel ortalama değerleri ilkbahar mevsiminde 196.6 gün.yaz mevsiminde 145.8 gün, sonbahar mevsiminde 98.2 gün ve kış mevsiminde 135.6 gün tespit edilmiştir. Mevsimlere göre senis periyodu ortalamaları arasındaki farklılıklar önemli derecede yüksek (P<0.01) bulunmuştur.

This study was carried out to investigate the effects of seasons on fertility traits in Brown Swiss herd at Konya Livestock Research Center. The breeding records of 637 Brown Swiss cows in between 1976-1985 years were used as the investigation material.The total averages of calving intervals were 390.1 days in winter, 355.1 days in spring, 413.9 days in summer and 384.9 days in autumn.The differences of the averages of seasonal calving intervals were not significant.In general calculation, it was found that the averages of the gestation lengths were 288.6 days in spring, 284.9 days in summer, 287.1 days in autumn and 287.8 days in winter.The diferences of the averages were significant (P<0.05)The general averages of the service periods were 196.6, 145.8, 98.2 and 135.6 days in spring, summer, autumn and winter respectively. The differences of the averages were significant (P<0.01).In general calculation the averages of the intenvals from parturition to first inseminaıion were 74.8 days in winter and spring, 103.8 days in summer and 81.7 days in autumn. The differences of the averages were significant (P<0.01).In general calculation it was found that the averages of the intervals from first insemination to conception were the highest (922 days) in summer and the lowest (30.1 days) in autumn. They were 60.1 and 31.8 days in spring and winter,respectively. The differences of the averages were not significant and the F value was 1.557. In general averages, it was found that the highest values of gestation lengths and service periods were in spring and those of intervals from parturition to firts insemination, calving intervals and intervals from firts insemination to conception were in summer.