 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Trend Analysis on Milk production Traits in the Dairy Farming Promotion Organization of Thailand) ผู้เขียน: Sanao Katkasame,  ดร.ศรเทพ ธัมวาสร, ศาสตราจารย์ , นายบัณฑิต ธานินทร์ธราธาร, อาจารย์ , Somkiert Pasanpanich สื่อสิ่งพิมพ์:pdf AbstractA total of 976 first lactation records from Dairy Farming Promotion Organization of Thailand during the years 1972 to 1991 were used to evaluate phenotypic trend and genetic trend on sire contributions. All records were analyzed to obtain the solutions from solving the fixed and mixed model equations. Year of sire birth was considered to provide genetic grouping based on sire contributions. By regressing year of calf solutions on time, estimates of phenotypic changes were obtained. Genetic trend based on sire contribution were obtained by regressing year of sire birth solution on time. The phenotypic trends per year on milk yield, milk fat and fat percentage were found to be 35.98 kg, 1.2589 kg and -0.0104%, respectively. Genetic trend based on sire contribution for three traits were 45.05 kg, 0.448 kg and -0.0544% per year, respectively. |