Genetic parameters of milk and lactation curve traits of dairy cattle from research farms in Thailand
Objective This study was aimed to estimate the genetic parameters, including genetic and phenotypic correlations, of milk yield, lactation curve traits and milk composition of Thai dairy cattle from three government research farms. Methods The data of 25,789 test-day milk yield and milk composition...
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| Format: | Article |
| Language: | English |
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Asian-Australasian Association of Animal Production Societies
2022-10-01
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| Series: | Animal Bioscience |
| Subjects: | |
| Online Access: | http://www.animbiosci.org/upload/pdf/ab-21-0559.pdf |
| _version_ | 1798032032507363328 |
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| author | Santi Pangmao Peter C. Thomson Mehar S. Khatkar |
| author_facet | Santi Pangmao Peter C. Thomson Mehar S. Khatkar |
| author_sort | Santi Pangmao |
| collection | DOAJ |
| description | Objective This study was aimed to estimate the genetic parameters, including genetic and phenotypic correlations, of milk yield, lactation curve traits and milk composition of Thai dairy cattle from three government research farms. Methods The data of 25,789 test-day milk yield and milk composition records of 1,468 cattle from lactation 1 to 3 of Holstein Friesian (HF) and crossbred HF dairy cattle calved between 1990 and 2015 from three government research farms in Thailand were analysed. 305-day milk yield was estimated by the Wood model and a test interval method. The Wood model was used for estimating cumulative 305-day milk yield, peak milk yield, days to peak milk yield and persistency. Genetic parameters were estimated using linear mixed models with herd, breed group, year and season of calving as fixed effects, and animals linked to a pedigree as random effects, together with a residual error. Univariate models were used to estimate variance components, heritability, estimated breeding values (EBVs) and repeatability of each trait, while pairwise bivariate models were used to estimate covariance components and correlations between traits in the same lactation and in the same trait across lactations. Results The heritability of 305-day milk yield, peak milk yield and protein percentage have moderate to high estimates ranging from 0.19 to 0.45 while days to peak milk yield, persistency and fat percentage have low heritability ranging from 0.08 to 0.14 in lactation 1 cows. Further, heritability of most traits considered was higher in lactation 1 compared with lactations 2 and 3. For cows in lactation 1, high genetic correlations were found between 305-day milk yield and peak milk yield (0.86±0.07) and days to peak milk yield and persistency (0.99±0.02) while estimates of genetic correlations between the remaining traits were imprecise due to the high standard errors. The genetic correlations within the traits across lactation were high. There was no consistent trend of EBVs for most traits in the first lactation over the study period. Conclusion Both the Wood model and test interval method can be used for milk yield estimates in these herds. However, the Wood model has advantages over the test interval method as it can be fitted using fewer test-day records and the estimated model parameters can be used to derive estimates of other lactation curve parameters. Milk yield, peak milk yield and protein percentage can be improved by a selection and mating program while days to peak milk yield, persistency and fat percentage can be improved by including into a selection index. |
| first_indexed | 2024-04-11T20:06:14Z |
| format | Article |
| id | doaj.art-c549fdf502244e089f0910ec014fb719 |
| institution | Directory Open Access Journal |
| issn | 2765-0189 2765-0235 |
| language | English |
| last_indexed | 2024-04-11T20:06:14Z |
| publishDate | 2022-10-01 |
| publisher | Asian-Australasian Association of Animal Production Societies |
| record_format | Article |
| series | Animal Bioscience |
| spelling | doaj.art-c549fdf502244e089f0910ec014fb7192022-12-22T04:05:18ZengAsian-Australasian Association of Animal Production SocietiesAnimal Bioscience2765-01892765-02352022-10-0135101499151110.5713/ab.21.055924886Genetic parameters of milk and lactation curve traits of dairy cattle from research farms in ThailandSanti Pangmao0Peter C. Thomson1Mehar S. Khatkar2 Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW 2570, Australia Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW 2570, Australia Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW 2570, AustraliaObjective This study was aimed to estimate the genetic parameters, including genetic and phenotypic correlations, of milk yield, lactation curve traits and milk composition of Thai dairy cattle from three government research farms. Methods The data of 25,789 test-day milk yield and milk composition records of 1,468 cattle from lactation 1 to 3 of Holstein Friesian (HF) and crossbred HF dairy cattle calved between 1990 and 2015 from three government research farms in Thailand were analysed. 305-day milk yield was estimated by the Wood model and a test interval method. The Wood model was used for estimating cumulative 305-day milk yield, peak milk yield, days to peak milk yield and persistency. Genetic parameters were estimated using linear mixed models with herd, breed group, year and season of calving as fixed effects, and animals linked to a pedigree as random effects, together with a residual error. Univariate models were used to estimate variance components, heritability, estimated breeding values (EBVs) and repeatability of each trait, while pairwise bivariate models were used to estimate covariance components and correlations between traits in the same lactation and in the same trait across lactations. Results The heritability of 305-day milk yield, peak milk yield and protein percentage have moderate to high estimates ranging from 0.19 to 0.45 while days to peak milk yield, persistency and fat percentage have low heritability ranging from 0.08 to 0.14 in lactation 1 cows. Further, heritability of most traits considered was higher in lactation 1 compared with lactations 2 and 3. For cows in lactation 1, high genetic correlations were found between 305-day milk yield and peak milk yield (0.86±0.07) and days to peak milk yield and persistency (0.99±0.02) while estimates of genetic correlations between the remaining traits were imprecise due to the high standard errors. The genetic correlations within the traits across lactation were high. There was no consistent trend of EBVs for most traits in the first lactation over the study period. Conclusion Both the Wood model and test interval method can be used for milk yield estimates in these herds. However, the Wood model has advantages over the test interval method as it can be fitted using fewer test-day records and the estimated model parameters can be used to derive estimates of other lactation curve parameters. Milk yield, peak milk yield and protein percentage can be improved by a selection and mating program while days to peak milk yield, persistency and fat percentage can be improved by including into a selection index.http://www.animbiosci.org/upload/pdf/ab-21-0559.pdfdairy cattlelactation curvewood model |
| spellingShingle | Santi Pangmao Peter C. Thomson Mehar S. Khatkar Genetic parameters of milk and lactation curve traits of dairy cattle from research farms in Thailand Animal Bioscience dairy cattle lactation curve wood model |
| title | Genetic parameters of milk and lactation curve traits of dairy cattle from research farms in Thailand |
| title_full | Genetic parameters of milk and lactation curve traits of dairy cattle from research farms in Thailand |
| title_fullStr | Genetic parameters of milk and lactation curve traits of dairy cattle from research farms in Thailand |
| title_full_unstemmed | Genetic parameters of milk and lactation curve traits of dairy cattle from research farms in Thailand |
| title_short | Genetic parameters of milk and lactation curve traits of dairy cattle from research farms in Thailand |
| title_sort | genetic parameters of milk and lactation curve traits of dairy cattle from research farms in thailand |
| topic | dairy cattle lactation curve wood model |
| url | http://www.animbiosci.org/upload/pdf/ab-21-0559.pdf |
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