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| Almeida,Tatiana Prestes; Kern,Elisandra Lurdes; Daltro,Darlene dos Santos; Braccini Neto,José; McManus,Concepta; Thaler Neto,André; Cobuci,Jaime Araujo. |
| ABSTRACT This study aimed to estimate heritability, genetic, and residual correlations between reproductive traits such as age at first calving, calving interval, dry period, and first service period and linear type traits measured in Holstein cows born between the years 1990 and 2008 in Brazil. The (co)variance components were estimated by restricted maximum likelihood, using the MTDFREML software. The heritability for reproductive traits and linear-type traits ranged from 0.02 to 0.03 and from 0.07 to 0.40, respectively. Estimates of genetic correlations between reproductive and linear-type traits ranged from -0.23 (top line) to 0.28 (angularity) to age at first calving, from -0.54 (final score) to 0.34 (foot angle) to calving interval, from -0.23... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Age at first calving; Dairy cattle; Genetic parameters; Reproductive efficiency. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982017000200091 |
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| Silva,Mário Henrique Magalhães Araújo da; Malhado,Carlos Henrique Mendes; Kern,Elisandra Lurdes; Daltro,Darlene dos Santos; Cobuci,Jaime Araujo; Carneiro,Paulo Luiz Souza. |
| ABSTRACT The objective of this study was to evaluate inbreeding depression in Holstein cows in Brazil, considering their 305-day milk production (MP), age of first calving (AFC), and calving interval (CI). The effects of inbreeding depression on the traits were determined using four regression models (linear, quadratic, exponential, and Michaelis-Menten) about the errors generated by the animal model. The linear model was significant for CI, and the quadratic model was significant for CI and AFC. The Michaelis-Menten and exponential models were significant for MP, AFC, and CI. Inbreeding depression affected MP and CI. Cows with inbreeding coefficient of 15% produced approximately 260 kg less milk than non-inbred cows. A 1% increase in the inbreeding level... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Calving interval; Inbreeding coefficient; Linear models; Non-linear models. |
| Ano: 2019 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982019000100307 |
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