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.
2019
Sammendrag
The objective of this paper was to examine how cutting frequency, silage fermentation patterns and clover performance in grass-clover swards influence the use of inputs and profitability in an organic dairy system. A linear programming model was developed to compare a three-cut and a two-cut system for a model farm in Central Norway, either with restricted or extensive silage fermentation at low or high red clover (Trifolium pratense L.) proportion in the sward, giving 8 different silage types in all. Input-output relations incorporated into the model were derived from a meta-analysis of organic grassland field trials in Norway as well as a silage fermentation experiment, and with feed intakes and milk yields from simulations with the ‘TINE Optifôr’ feed ration planner in the Norfor feed evaluation system. The model maximized total gross margin of farms with 260,000 l milk quota and housing capacity for 45 cows, with separate model versions for each of the 8 silage types. Farmland availability varied from 30 to 70 ha with 40 ha as the basis. Our results suggested that farmland availability and marginal return of a competing barley crop profoundly influenced the profitability of the different silage types. A high clover proportion increased dry matter (DM) yields and was far more important for profitability than the score on the other factors considered at restricted land availabilities. Profits with the three-cut systems were always greater than those with the two-cut systems, the former being associated with greater silage intakes and improved dairy cow performances but lower DM forage yields. Three-cut systems were further favoured as land availability increased and also by a lower marginal return of barley. Although use of an acidifying silage additive improved feed intakes and milk production per cow, the practice reduced total milk production and depressed profit compared to untreated, extensively fermented silage at restrictive land availabilities. With more land available, and in particular at a low marginal return of barley, use of a silage additive was profitable.
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With increasing intensification of the dairy sector in many countries and with the introduction of automatic milking, exercise paddocks combined with full indoor feeding, as an alternative to production pasture, are being used as a compromise between farm economics and cow welfare. This study examined whether there are production benefits for high-producing dairy cows in an alternative system that uses pasture at a level of approximately 50% of the total roughage intake in the diet. In an automatic milking system with 12-h night access to the outdoor environment, we compared milk production and behavior of cows in 2 systems: an exercise paddock combined with ad libitum grass silage indoor feeding and a production pasture combined with a restricted daytime grass silage ration. There were 20 cows in the former and 21 cows in the latter system, with the treatments running in parallel. The experiment started in late June with no complete darkness during the night, and lasted for 12 wk, with 5.6 h of darkness at the end. We therefore also explored the effect of night length on milk production and behavior parameters. All cows showed strong motivation for going outdoors and grazing when pasture access was given in early evening, but after a few hours both groups went to the barn and did not return to the pasture area during the remaining night. As the season progressed and nights became longer, cows on the exercise paddock treatment reduced time spent outdoors and grazing time, whereas they increased time spent resting outdoors. The group on exercise paddock had a greater milk yield (kg of milk) over the experimental period than the production pasture group. The latter group also showed a greater drop in milk yield over the duration of the trial. Thus, for cows milked in an automatic milking system and offered nighttime outdoor access, no milk production benefits were observed in offering production pasture with restricted indoor silage allowance instead of an exercise paddock with ad libitum silage. We therefore suggest that automatic milking farmers with similar production levels and automatic milking-management systems as in the present experiment, who wish to in-clude grazed grass as part of the dairy cow diet, should ensure that cows have pasture access in the afternoon and evening.
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Kuldetolerante grønnsaker er planter som har utviklet beskyttelse av vekstpunktet mot kulde og frost. Selv med noen frostnetter er, fortsetter disse plantene å vokse når temperatur og lys om dagen, tillater det. Det gir unike muligheter til å utvide grønnsakssesongen, og gi en «skuldersesong» fra sensommer til tidlig vinter. Egnede planter står ute på feltet gjennom vinteren, for å gi produksjon tidlig neste vår. Fordelene med produksjon av kuldetolerante grønnsaker, er innføring av en ny «skuldersesong», redusert næringstap fra jorda, lite utfordringer med skadedyr, gi et større mangfold innen nyhøstete vintergrønnsaker til forbruker, øke verdigrunnlaget for dyrkere og øke regionale muligheter for sysselsetting. Det er utført vekstforsøk på tre utvalgte steder i landet med ulike årsvariasjoner, med hensyn til daglengde og temperatur. Grønnsakssorter ble valgt ut etter evne til å tolerere kulde i tillegg til rask utviklingstid. Mange av disse grønnsakene har en stor utfordring med stokkrenning, men løsningen ble sen såing, fra slutten av juli til begynnelsen av august. Det blir tidligere lave temperaturer i Nord-Norge og og til dels på Østlandet, slik at den optimale vekstperioden er noe kortere enn på Sørlandet. Det ble testet om forkultivering inne av småplanter for utsetting på felt, kunne bidra til å gi større planter før høsting. I våre forsøk etablerte de direktesådde grønnsakene seg raskest og fikk størst avling. Grønnsakene fikk også en mildere og søtere smak om de ble høstet etter en liten kuldeperiode.