Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2009
Sammendrag
Geiter har en utpreget sosial motivasjon og setter pris på stabilitet i sitt sosiale miljø. Plasskrav, fortildeling og gruppestørrelse er viktige faktorer som alle påvirker aggresjonsnivået og harmonien i en flokk, og som derfor også kan påvirke produksjonen på lang sikt.
Sammendrag
Presentasjon av resultater fra to års forsøk i prosjektet "Organic protein feed and edible oil from oilseed crops". Resultater fra nitrogen- og svovelgjødsling til høstoljevekstene høstrybs og -raps diskuteres. Resultater fra forsøk med nitrogengjødsling til vårrybs og dodre blir også presentert sammen med enkelte kvalitetsanalyser. De foreløpige resultatene viser at dodren kan være en interessant vekst. Den kan virke mer nøysom enn vårrybs, og det ser ikke ut til at den har de samme utfordringene med skadedyr som vårrybs. Når det gjelder vårrybs ser det foreløpig ut til at en kan oppnå et akseptabelt avlingsnivå ved bruk av husdyrgjødsel.
Forfattere
Randi Therese Garmo Adam Dunstan Martin Adam Dunstan Martin Erling Thuen Øystein Havrevoll Håvard Steinshamn Egil Prestløkken Åshild T. Randby Åshild T. Randby Margrete Eknæs Andres Waldmann Olav ReksenSammendrag
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 ovulation type I was defined as consistently low progesterone concentration, <3 ng/mL for >= 50 d postpartum. Delayed ovulation type II was defined as prolonged interluteal interval with milk progesterone measurements <3 ng/mL for >= 12 d between 2 luteal phases. Persistent corpus luteum (PCL) type I was defined as delayed luteolysis with milk progesterone >= 3 ng/mL for >= 19 d during the first estrous cycle postpartum. Persistent corpus luteum type II was defined as delayed luteolysis with milk progesterone >= 3 ng/mL for >= 19 d during subsequent estrous cycles before first artificial insemination. Delayed ovulation type I was present in 14.7%, delayed ovulation type II in 2.8%, PCL type I in 6.7%, and PCL type II in 3.3% of the profiles. Commencement of luteal activity was related to milk yield, parity, PCL type I, and the summated occurrence of PCL type I and II. The least squares means for the interval to commencement of luteal activity were 24.2 d when PCL type I and II were present and 29.5 d when PCL type I and II were absent. The likelihood of pregnancy to first service was not affected in cows with a history of PCL when artificial insemination was carried out at progesterone concentrations <3 ng/mL (i.e., during estrus); however, cows that had experienced PCL were more likely to be inseminated during a luteal phase. The occurrence of delayed ovulation and PCL in Norwegian Red cows was less than that reported in most other dairy populations.
Forfattere
Randi Therese Garmo Erik Ropstad Øystein Havrevoll Erling Thuen Håvard Steinshamn Andres Waldmann Olav ReksenSammendrag
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 ng/mL not earlier than 10 d after calving. Selection line was significantly related to C-LA, so that the least squares mean days from calving to C-LA were 22.5, 30.4, and 27.2 d for LMP, HMP, and HI cows, respectively. The HMP cows produced more milk than the LMP cows. The average milk yield in the sixth week of lactation was 24.0, 27.1, and 25.3 kg for LMP, HMP, and HI cows, respectively. The interval to C-LA decreased for the HMP and HI cows after phenotypic adjustment for EB in the model. Least squares means for the interval to C-LA were 23.2, 29.7, and 25.6 d for the LMP, HMP, and HI cows, respectively, in a model that included parity, selection lines, and EB as covariates. Cumulated EB during the first 4 wk of lactation, which itself differed between selection lines, did not fully account for differences in interval to C-LA between selection lines. Thus, the results of the present investigation indicate that selection for milk yield negatively affects C-LA over and above the effects caused by concurrent changes in EB. The increase in days to C-LA caused by selection for high yields can be reduced if selection for milk yield is combined with fertility in the breeding program.
Forfattere
Håvard SteinshamnSammendrag
The review confirms that feeding legume silage leads to higher DMI and milk production than grass. White clover is superior to red clover and red clover to lucerne in milk yield relative to intake. Milk fat content is lower on red clover than on grass diets and red clover yield milk with lower protein content than white clover and lucerne. Red clover yields milk with higher proportion of the fatty acids C18:2n-5 and C18:3n-3 than grass and higher content of equol than grass and white clover.
Forfattere
Steffen Adler Annette Veberg Dahl Håvard Steinshamn Anne Holter Vae Erling Thuen Torstein H. Garmo Søren Krogh-JensenSammendrag
A continuous grazing experiment with three measurement periods, 3 weeks each, was conducted with 16 Norwegian Red dairy cows in mid lactation to compare milk quality when grazing red clover-grass (R) or botanical diverse pasture (D). The cows were offered either R or D from the start of grazing season in mid May until beginning of September 2008. Milk yield was measured and milk samples were collected in the last week in each period (end of June, beginning of August and end of August). Pasture type had no effect on milk yield and milk content of fat or protein. Cows grazing R had higher proportion of the fatty acids C18:0 (22.41 vs. 9.96, P<0.05) and C18:1t11 (0.58 vs. 0.44 g/100g FAME, P<0.05) and lower proportion of C16:0 (27.83 vs. 30.92, P<0.05) in their milk fat than the cows grazing D. The milk content of ?-tocopherol was higher in milk from R than D (3.01 vs. 2.64 µg/ml, P<0.05). The oxidative stability of the milk lipids were only minor affected by pasture type.
Forfattere
Steffen Adler Annette Veberg Dahl Håvard Steinshamn Anne Holter Vae Erling Thuen Torstein H. Garmo Søren Krogh-JensenSammendrag
Et kontinuerlig beiteforsøk med 3 perioder à 3 uker ble gjennomført med 16 NRF-kyr i midtlaktasjonen. Målsetningen var å sammenligne melkequalitet når kyrne beitet rødkløvergras (RB) eller botanisk allsidig beite (AB). beitetype hadde ingen effekt på ytelse, melkas fettinnhold eller proteininnhold. Kyr som beitet RB hadde en høyere andel av fettsyrene C18:0 (22.41 vs. 9.96, P<0.05) og C18:1t11 (0.58 vs. 0.44 g/100g FAME, P<0.05) og lavere andel C16:0 (27.83 vs. 30.92, P<0.05) i melkefettet sammenlignet med kyr som beitet AB. Innholdet av alfatokoferol var høyere i melk fra RB enn AB (3.01 vs. 2.64 µg/ml, P<0.05). Den oksidative stabiliteten av melkas lipider ble bare i mindre grad påvirket av beitetype.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Håvard SteinshamnSammendrag
Dei totale fôrkostnadane utgjer om lag 80% og grovfôrkostnadane 60% av dei variable kostnadane i sjølvrekrutterande storkjøttproduksjonen (Nortura). Det kan derfor være mye å hente økonomisk dersom det er mulig å betre effektiviteten i fôrutnyttinga.