The use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of Iranian dairy cows
The objective of this study was to estimate lactation curve parameters with Dijkstra mechanistic model and to evaluate genetic and phenotypic relationships between the parameters and the average somatic cell count in primiparous cows. The finding indicated that heritability estimates for partial mil...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Editora da Universidade Estadual de Maringá (Eduem)
2020-06-01
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| Series: | Acta Scientiarum: Animal Sciences |
| Subjects: | |
| Online Access: | http://www.periodicos.uem.br/ojs/index.php/ActaSciAnimSci/article/view/50181 |
| _version_ | 1828787216175857664 |
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| author | Mahdi Elahi Torshizi Homayoun Farhangfar |
| author_facet | Mahdi Elahi Torshizi Homayoun Farhangfar |
| author_sort | Mahdi Elahi Torshizi |
| collection | DOAJ |
| description | The objective of this study was to estimate lactation curve parameters with Dijkstra mechanistic model and to evaluate genetic and phenotypic relationships between the parameters and the average somatic cell count in primiparous cows. The finding indicated that heritability estimates for partial milk yield (PMY1, PMY2 and PMY3), total 305-day milk yield (TMY305), decay parameter (λ2), age at first calving (AFC) and peak yield (PY) were moderate while the heritability of persistency (PS%), average somatic cell score (AVGSCS), time to peak yield (TP), initial milk production (λ0), specific rate of cell proliferation at parturition (λ1), and specific rate of cell death (λ3) were quite low. Genetic correlations between both AFC and PS% traits with average somatic cell scores was negative (-0.047 and -0.060) but low positive genetic correlation were between partial milk yields (PMY1 and PMY3) while negative genetic correlation (-0.06) was obtained between TMY305 and AVGSCS. Differences between TMY305 of cows with less than 100000 cells mL-1 and cows with >1,500,000 cells mL-1 was approximately 708 Kg and is equivalent to 8% loss of milk yield/cow during lactation period and also loss of persistency (11.1 %( was shown for the extreme classes of SCC in this study. |
| first_indexed | 2024-12-12T00:27:21Z |
| format | Article |
| id | doaj.art-69cadcb6c1714865b6553f8f1db9850c |
| institution | Directory Open Access Journal |
| issn | 1806-2636 1807-8672 |
| language | English |
| last_indexed | 2024-12-12T00:27:21Z |
| publishDate | 2020-06-01 |
| publisher | Editora da Universidade Estadual de Maringá (Eduem) |
| record_format | Article |
| series | Acta Scientiarum: Animal Sciences |
| spelling | doaj.art-69cadcb6c1714865b6553f8f1db9850c2022-12-22T00:44:35ZengEditora da Universidade Estadual de Maringá (Eduem)Acta Scientiarum: Animal Sciences1806-26361807-86722020-06-0142e50181e5018110.4025/actascianimsci.v42i1.5018150181The use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of Iranian dairy cowsMahdi Elahi Torshizi0Homayoun Farhangfar1Islamic Azad UniversityUniversity of BirjandThe objective of this study was to estimate lactation curve parameters with Dijkstra mechanistic model and to evaluate genetic and phenotypic relationships between the parameters and the average somatic cell count in primiparous cows. The finding indicated that heritability estimates for partial milk yield (PMY1, PMY2 and PMY3), total 305-day milk yield (TMY305), decay parameter (λ2), age at first calving (AFC) and peak yield (PY) were moderate while the heritability of persistency (PS%), average somatic cell score (AVGSCS), time to peak yield (TP), initial milk production (λ0), specific rate of cell proliferation at parturition (λ1), and specific rate of cell death (λ3) were quite low. Genetic correlations between both AFC and PS% traits with average somatic cell scores was negative (-0.047 and -0.060) but low positive genetic correlation were between partial milk yields (PMY1 and PMY3) while negative genetic correlation (-0.06) was obtained between TMY305 and AVGSCS. Differences between TMY305 of cows with less than 100000 cells mL-1 and cows with >1,500,000 cells mL-1 was approximately 708 Kg and is equivalent to 8% loss of milk yield/cow during lactation period and also loss of persistency (11.1 %( was shown for the extreme classes of SCC in this study.http://www.periodicos.uem.br/ojs/index.php/ActaSciAnimSci/article/view/50181genetic parameters; milk yield traits; persistency; somatic cell count. |
| spellingShingle | Mahdi Elahi Torshizi Homayoun Farhangfar The use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of Iranian dairy cows Acta Scientiarum: Animal Sciences genetic parameters; milk yield traits; persistency; somatic cell count. |
| title | The use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of Iranian dairy cows |
| title_full | The use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of Iranian dairy cows |
| title_fullStr | The use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of Iranian dairy cows |
| title_full_unstemmed | The use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of Iranian dairy cows |
| title_short | The use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of Iranian dairy cows |
| title_sort | use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of iranian dairy cows |
| topic | genetic parameters; milk yield traits; persistency; somatic cell count. |
| url | http://www.periodicos.uem.br/ojs/index.php/ActaSciAnimSci/article/view/50181 |
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