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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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Garmo, Randi T.; Martin, A.D.; Thuen, E.; Havrevoll, Ø.; Steinshamn, H.; Prestløkken, E.; Randby, Å.; Eknæs, M.; Waldmann, A.; Reksen, O.. |
Progesterone profiles in Norwegian Red cows were categorized, and associations between the occurrence of irregularities in the profiles and the commencement of luteal activity were investigated. The cows were managed in 3 feeding trials from 1994 to 2001 and from 2005 to 2008 at the Norwegian University of Life Sciences. The cows were followed from calving, and the milk samples collected represented 502 lactations from 302 cows. Milk samples for progesterone analysis were taken 3 times weekly from 1994 throughout 1998 and from 2005 to 2008 and 2 times weekly from 1999 to 2001. Commencement of luteal activity was defined as the first day of 2 consecutive measurements of progesterone concentration ≥3 ng/mL not earlier than 10 d after calving. Delayed... |
Tipo: Journal paper |
Palavras-chave: Dairy cattle; Production systems; Animal husbandry; Breeding and genetics. |
Ano: 2009 |
URL: http://orgprints.org/16851/1/Garmo_etal_2009_prog_profiles_NRF.pdf |
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