Türk Tarım ve Doğa Bilimleri Dergisi

Yazarlar: Kemal YAZGAN, Jale METIN KIYICI

Konular:-

Anahtar Kelimeler:Random regression model,Functional milk traits,Genetic parameter

Özet: The objective of this study was to estimate heritabilities and to investigate the genetic relationship between some functional milk traits such as milk yield (MY), dry matter (DM), fat (F) and milking duration (MD) on Brown Swiss dairy cattle breeding in Turkey with random regression model using heterogeneous residual error variance interval. Variance components were estimated with 4 multiple-trait (4 traits at a time) random regression model via restricted maximum likelihood (REML) with AI-REML algorithm. Data were obtained from an experimental farm and comprised 636 test day (TD) records for each trait. Average heritability for MY, DM, F and MD were 0.29, 0.10, 0.16 and 0.05, respectively. The largest genetic correlation interval were found between F and MD and ranged from -0.34 to 0.72 throughout lactation. The shape of genetic correlation curve of DM-MD was similar to F-MD and genetic correlation between DM-MD ranged from -0.24 to 0.61. Genetic correlations of other traits changed from 0.08 to 0.65 for MY-DM, -0.16 to 0.28 for MY-MD and 0.04 to 0.59 for MY-F throughout lactation. Results from this study implied that increasing fat percentage in milk and other milk components may have led to decrease the flow of milk and consequently, affected the milking duration.

---