İNGİLTERE'DEKİ SİYAH-ALACA SIĞIRLARIN DÖL VERİMİ ÖZELLİKLERİ ÜZERİNDE ARAŞTIRMALAR

OZET Bu calisma, sigir yetistiriciligi bakimindan gelismis bir ulke olan Ingiltere'deki rastgele secilmis bes ayri ozel isletmede yetistirilen Siyah-Alaca sigirlarin bazi dol verimi ozelliklerinin belirlenmesi ve bu verimler uzerinde bazi cevre faktorlerinin etkilerinin incelenmesi amaciyla yapilmistir. Arastirmanin materyalini 1993-2003 yillari arasinda yetistirilen Siyah-Alaca sigirlardan elde edilen verim degerleri olusturmustur. Arastirmada, dol verimi ozellikleri icin 720, buzagilama araligi ve acik periyod icin 1847 verim degeri incelenmistir. Siyah-Alaca sigirlarin oransal dol verimi ozellikleri arasindaki farkliliklarin istatistik analizlerinde t-testi, diger verimler icin Duncan-testi, duzeltilmis ortalama degerlerin etki paylari icin contrast-testi kullanilmistir. Calismada gebelik, kisirlik, normal dogum, abort, olu ve ikiz dogum oranlari sirasiyla %97.08, %2.92, %95.56, %0.97, %0.56 ve %0.56 duzeylerinde bulunmustur. Sigirlarin ilk buzagilama yasi 26.20 ay, dogumdan sonraki ilk tohumlama araligi 77.35 gun, bir gebelik icin yapilan tohumlama sayisi 1.64, iki dogum arasindaki buzagilama araligi 389.00 gun ve acik periyod 112.07 gun duzeylerinde belirlenmistir. Arastirmada, verimler uzerinde etkili cevre faktorleri olarak, ciftlikler, gebelik sirasi, yil ve mevsimlerin etkileri incelenmistir. Oransal dol verimi ozelliklerinden gebelik, kisirlik, normal, olu ve ikiz dogumlar ve abort uzerinde ciftlik faktoru istatistik bakimindan onemli (P 0.05) bulunmustur, ilk buzagilama yasi ve dogumdan sonraki ilk tohumlama araligi icin tum faktorlerin P 0.05), buzagilama araligi ve acik periyot icin yil ve mevsimin onemli (P 0.05) oldugu belirlenmistir. Bu arastirmada elde edilen sonuclar, isletmelerin sigir yetistiriciligi icin gerekli optimum kosullari saglayarak yuksek duzeyde verim elde ettiklerini gostermektedir. Hayvanlara uygulanan management ve kullanilan daha yuksek verimli damizlik materyal yillar arasinda daha yuksek verime ulasilmasini saglamistir. Anahtar Kelimeler: Sigir, Siyah-Alaca, dolverimi ozellikleri, Ingiltere. ABSTRACT STUDIES ON REPRODUCTIVE TRAITS OF HOLSTEIN-FRIESIAN CATTLE IN ENGLAND This study was conducted to investigate the reproductive traits of Holstein-Friesian cattle in five randomly chosen private farms in England which have a developed cattle management policy. Also the effects of the individual farm environments on the above traits have been observed. The material of the study was the yield records of the Holstein-Friesian cattle between the years 1993-2003. During the study 720 records were examined for reproductive traits, 1847 records were investigated for the calving interval and open periods. For the statistical analysis of the rational reproductive traits the t-test have been employed Duncan-test was used for other yields and contrast-test for corrected mean values of Effect ratios. The pregnancy, barren, normal birth, abort, still-birth and twin rates were respectively 97.08%, 2.92%, 95.56%, 0.97%, 0.56% and 0.56%. The first calving age of the cows was 26.20 months, the calving to first service interval was 77.35 days, number of inseminations for a pregnancy was 1.64, the calving interval was 389.00 days and open period was 112.07 days. Effects of environmental factors such as the individual farm environments, parity, year and season on the yields were examined in the study. Rational reproductive traits such as pregnancy, barren, normal birth, twin or still births and abort rates were observed to be affected by the individual farm environments significantly (P 0.05). All the factors were significantly effective on the first calving age (P 0.05). The effect of year and season on the calving interval and the open period was significantly important (P 0.05). The results of this study have shown that the cattle breeding farms can obtain high level yields by providing optimal conditions to the animals. Management conditions and high quality breeders have enabled the farms to reach higher yields every passing year. Keywords: Cattle, Holstein-Friesian, reproductive traits, England.