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| Garmo, Randi T.; Ropstad, E.; Havrevoll, Ø.; Thuen, E.; Steinshamn, H.; Waldmann, W.; Reksen, O.. |
| Relationships among commencement of luteal activity (C-LA), milk yield, and energy balance (EB) were investigated in 3 selection lines of Norwegian Red cows at the Norwegian University of Life Sciences from 1994 through 2001. The cows were selected for low genetic merit for milk yield (LMP), high genetic merit for milk yield (HMP), and a combination of high indices for milk yield and fertility (HI). Breeding values for fertility were based on 56-d nonreturn rate. The material included 268 lactations from 147 cows. Milk samples for progesterone analysis were drawn 3 times weekly from 1994 through 1998, and 2 times weekly from 1999 to 2001. Commencement of luteal activity was defined as the first 2 consecutive measurements of progesterone concentration >3... |
| Tipo: Journal paper |
Palavras-chave: Dairy cattle; Animal husbandry; Breeding and genetics; Feeding and growth. |
| Ano: 2009 |
URL: http://orgprints.org/16852/1/Garmo_etal_Commencement_of_luteal_activity_%2D_dairy_cow_selection_lines.pdf |
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