Modeling extended lactations of dairy cows
Nine mathematical models were compared for their ability to predict daily milk yields (n 294,986) in standard 305-d and extended lactations of dairy cows of Costa Rica. Lactations were classified by parity (first and later), lactation length (9 to 10, 11 to 12, 13 to 14, 15 to 16, and 16 to 17 mo)...
| Autores principales: | , , , |
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| Formato: | Journal Article |
| Lenguaje: | Inglés |
| Publicado: |
2000
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| Acceso en línea: | https://hdl.handle.net/10568/2185 |
| _version_ | 1855536461829373952 |
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| author | Vargas, B. Koops, W.J. Herrero, Mario Arendonk, Johan A.M. van |
| author_browse | Arendonk, Johan A.M. van Herrero, Mario Koops, W.J. Vargas, B. |
| author_facet | Vargas, B. Koops, W.J. Herrero, Mario Arendonk, Johan A.M. van |
| author_sort | Vargas, B. |
| collection | Repository of Agricultural Research Outputs (CGSpace) |
| description | Nine mathematical models were compared for their ability to predict daily milk yields (n 294,986) in standard 305-d and extended lactations of dairy cows of Costa Rica. Lactations were classified by parity (first and later), lactation length (9 to 10, 11 to 12, 13 to 14, 15 to 16, and 16 to 17 mo), and calving to conception interval (1 to 2, 3 to 4, 5 to 6, 7 to 8, and 9 to 10 mo). Of the nine models, the diphasic model and lactation persistency model resulted in the best goodness of fit as measured by adjusted coefficient of determination, residual standard deviation, and Durbin-Watson coefficient. All other models showed less accuracy and positively correlated residuals. In extended lactations, models were also fitted using only test-day records before 305 d, which resulted in a different ranking. The diphasic model showed the best prediction of milk yield in standard and extended lactations. We concluded that the diphasic model provided accurate estimates of milk yield for standard and extended lactations. Interpretation of parameters deserves further attention because of the large variation observed. As expected, the calving to conception interval was found to have a negative effect on milk yield for cows with a standard lactation length. In extended lactations, these negative effects of pregnancy on milk yield were not observed. |
| format | Journal Article |
| id | CGSpace2185 |
| institution | CGIAR Consortium |
| language | Inglés |
| publishDate | 2000 |
| publishDateRange | 2000 |
| publishDateSort | 2000 |
| record_format | dspace |
| spelling | CGSpace21852024-01-22T09:44:16Z Modeling extended lactations of dairy cows Vargas, B. Koops, W.J. Herrero, Mario Arendonk, Johan A.M. van Nine mathematical models were compared for their ability to predict daily milk yields (n 294,986) in standard 305-d and extended lactations of dairy cows of Costa Rica. Lactations were classified by parity (first and later), lactation length (9 to 10, 11 to 12, 13 to 14, 15 to 16, and 16 to 17 mo), and calving to conception interval (1 to 2, 3 to 4, 5 to 6, 7 to 8, and 9 to 10 mo). Of the nine models, the diphasic model and lactation persistency model resulted in the best goodness of fit as measured by adjusted coefficient of determination, residual standard deviation, and Durbin-Watson coefficient. All other models showed less accuracy and positively correlated residuals. In extended lactations, models were also fitted using only test-day records before 305 d, which resulted in a different ranking. The diphasic model showed the best prediction of milk yield in standard and extended lactations. We concluded that the diphasic model provided accurate estimates of milk yield for standard and extended lactations. Interpretation of parameters deserves further attention because of the large variation observed. As expected, the calving to conception interval was found to have a negative effect on milk yield for cows with a standard lactation length. In extended lactations, these negative effects of pregnancy on milk yield were not observed. 2000-12-10 2010-08-05T07:40:03Z 2010-08-05T07:40:03Z Journal Article https://hdl.handle.net/10568/2185 en Limited Access Vargas, B.; Koops, W.J.; Herrero, M.; Arendonk, J.A.M. Van. 2000. Modeling extended lactations of dairy cows. Journal of Dairy Science 83:1371-1380. |
| spellingShingle | Vargas, B. Koops, W.J. Herrero, Mario Arendonk, Johan A.M. van Modeling extended lactations of dairy cows |
| title | Modeling extended lactations of dairy cows |
| title_full | Modeling extended lactations of dairy cows |
| title_fullStr | Modeling extended lactations of dairy cows |
| title_full_unstemmed | Modeling extended lactations of dairy cows |
| title_short | Modeling extended lactations of dairy cows |
| title_sort | modeling extended lactations of dairy cows |
| url | https://hdl.handle.net/10568/2185 |
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