Siyah Alaca Süt Verimine Ait Tekrarlama Derecesinin Farklı İstatistik Yöntemlerle Tahmini

Bu çalışmada, Ceylanpınar Tarım İşletmesi'nde yetiştirilen Siyah Alaca sürüsüne ait, iki buzağılama arasındaki süre, laktasyon süresi, laktasyon süt verimi, kuruda kalma süresi ve düzeltilmiş süt verimi (2x305 E.Ç.)'ne ilişkin verileri kullanarak, Kısıtlı En Çok Olabilirlik (KEÇO) yöntemiyle önemli verim özelliklerinin tekrarlama derecesini tahmin etmek ve KEÇO yöntemiyle, En Küçük Kuadratik Yansız Tahmin Edici (EKKYTE), Varyans Analizi (VA) ve En Çok Olabilirlik (EÇO) yöntemiyle bulunan tekrarlama derecelerini karşılaştırmak amaçlanmıştır. Çalışmada istatistik analizlerde süt verimi için ise 1457 kayıt kullanılmıştır. Siyah Alaca ineklerde önemli süt verim özelliklerine ait tekrarlama dereceleri 0,005 ile 0,244 arasında tahmin edilmiştir. Tekrarlama dereceleri düşük hesaplandığından, yapılacak ayıklamalarda iki veya daha fazla kayıtın ortalamasına göre seçim yapılması daha faydalı olabilir. Tekrarlama derecesinin tahmin edilmesinde, r>2Sr koşulunu sağlayan, iki buzağılama arasındaki süre, kuruda kalma süresi ve laktasyon süresinde EKKYTE yöntemi, laktasyon süt veriminde KEÇO ve EÇO yöntemi, düzeltilmiş süt verimi (2x305 E.Ç)'nde ise EKKYTE, VA, KEÇO ve EÇO yöntemleri güvenilir sonuçlar verebilir.

Estimation of the Repeatability of Holstein Milk Yields via Various Statistical Methods

This study aims at estimation the repeatability of vital yield characteristics through the RestrictedMaximum Likelihood (REML) method by the way of using data with regards to the calving intervals, lactationperiod, lactation milk yield, dry period and recovered milk yield (2x305 Max.) related to the Holstein herd raised inCeylanpınar Agriculture Enterprise and comparing the repeatability estimates determined with the help of theREML method, Minimum Quadratic Unbiased Estimation (MQUE), Variance Analysis (VA) and MaximumLikelihood (ML) method. The number of records used for milk yield in the statistical analysis is 1457. Therepeatability related to the milk yield characteristics was estimated to be between 0,005 and 0,244. Because of thefact that the repeatability was estimated to be low; it is believed that it might be useful to make the selection basedon the mean of two or more records. Estimating the repeatability; the Minimum Quadratic Unbiased Estimationmethod is most likely to give reliable results for the calving period, dry period and lactation period that meets ther>2Sr condition while REML and ML methods are most likely to give the most reliable results for lactation milkyield and MQUE, VA, REML and ML methods are most likely to give the best results for the adjusted milk yield(2x350 Max.).

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