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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Genotype by Region Interaction on Milk Production Traits of Holstein Crossbred Dairy Cows in Thailand) ผู้เขียน: Mohammed Endris,  ดร.ศรเทพ ธัมวาสร, ศาสตราจารย์ , ดร.พรรณวดี โสพรรณรัตน์, รองศาสตราจารย์ , ดร.สมเกียรติ ประสานพานิช, รองศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractThis study was designed to examine the existence of a genotype ? region interaction on milk production traits in Holstein crossbred dairy cows in Thailand. The data set for this study was provided by Department of Livestock Development of Thailand. The data were divided into five regions (Central, East, North, Northeast and West). The factors having genotype ? region interaction on milk production traits were region, year-season of calving, breed group and breed group ? region interaction. The investigated traits were actual total milk yield (ATMY), 305 d milk yield (MY305) and adjusted 305 d milk yield (AJ305), respectively. The breed group of cow had a significant (P < 0.05) effect on MY305 and a highly significant (P < 0.01) effect on ATMY and AJ305 while the effect of year-season of calving and region had very highly significant (P < 0.001) effects for all the studied traits. Breed group ? region had a highly significant interaction (P < 0.01) for the milk production traits. The estimated heritability for the milk production traits ranged between 0.17 to 0.24 for the Central region and 0.29 to 0.57 for the Eastern region. It was suggested that the performance of breed group of cows from different regions should differ significantly or there was a genotype ? region interaction in this particular study. |
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หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Genotype by Environment Interaction Effect on Lactation Pattern and Milk Production Traits in an Ethiopian Dairy Cattle Population) ผู้เขียน:Gebregziabher Gebreyohannes, ดร.ศกร คุณวุฒิฤทธิรณ, รองศาสตราจารย์ , Mauricio Aguirre Elzo, ดร.ธนาทิพย์ สุวรรณโสภี, รองศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractThe genotype by environment interaction (GEI) was evaluated for lactation milk yield (LY), initial milk yield (IY), peak milk yield (PY) and average milk yield per day (YD) in an Ethiopian multibreed dairy cattle population. Analyses used 4,488 lactation milk records from 1,320 cows collected at the Bako and Holetta research centers from 1979 to 2010. Breeds were Horro, Boran, Friesian crossbreds, Jersey crossbreds and Simmental crossbreds. The GEI for each trait was evaluated using estimates of cow breed group by environment (Bako and Holetta) interactions (univariate fixed models) and Spearman’s rank correlations between sire-predicted values for the same trait measured in both environments (bivariate mixed models). Friesian crossbreds had higher (P < 0.0001) least squares mean (LSM) values for LY, IY, PY and YD than Simmental and Jersey crossbreds at Holetta, whereas Friesian and Simmental crossbreds had higher (P < 0.0001) LSM values for LY, PY and YD than Jersey crossbreds at Bako. Correlations between sire rankings at Bako and Holetta were 0.86 for LY and IY and 0.87 for YD indicating that substantial re-ranking occurred across locations. Thus, multiple-trait models with phenotypic information from Bako and Holetta would be needed to accurately select the most appropriate sires for each location. |
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. |
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