Fræðaþing landbúnaðarins - 04.02.2005, Blaðsíða 103

kg/d, and a complete diet. It was concluded in that study that one should not increase
concentrate allowance by more than 0.3 kg daily during early lactation as higher rates
may increase the risk of rumen acidosis without any production benefíts.
This preliminary report on some aspects of the metabolic study included in the project of
different feeding strategies in the dry period and early lactation carried out at Stóra Armót
in 2002 - 2004 supports the view that there is a large between cow variation which is
causing problems in evaluating different feeding strategies. The metabolic regulation in
the transition period is immensely complex and there are still a lot of holes in the
knowlegde of that mechanism. Recent research in hormonal action shows that not only
does the concentration of the hormones change but also the sensitivity and response of
the target organ.
The results tell us irrespective of treatment that the cows suffer tremendous metabolic
strain in the early lactation as shown by the very high levels of NEFA and BOHB and at
the same time low levels of glucose. This is very much in line with previous studies in
Iceland which have shown a similar picture (Grétar H Harðarson 1980, 1995). This also
confirms that the Icelandic cow has a high risk of production diseases which is in
accordance with the limited health records available. The incidence rate of clinical
ketosis is around 20%, more than 400% higher than in the neighbouring countries. This
is totally unacceptable and one of the main reasons for moving from component feeding
to total mixed ration feeding at Stóra Armót which has been shown to increase DMI by
up to 24% in early lactation (Ingvartsen et al., 2001).
Heimildir
Bergman, E.N. 1971. Hyperketonaemia-ketogenesis and ketone body metabolism. J.Dairy Sci. 54. 936-948.
Bauman, D.E., Currie, W.B., 1980. Partitioning of nutrients during pregnancy and lactation: a review of
mechanisms involving homeostasis and homeorhesis. J. Dairy Sci. 63, 1514-1529
Dann, H.M., Varga, G.A., Putnam, D.E., 1999. Improving energy supply to late gestation and early
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Grétar Hrafh Harðarson, 1980. An investigation into bovine ketosis in Iceland and its relationship to
feeding practices. MPhil thesis. University of Edinburgh.
Grétar Hrafh Harðarson, Þorsteinn Olafsson og Gunnar Rikharðsson, 1995. Mismunandi orkufóðrun
mjólkurkúa í byijun mjaltaskeiðs. Ahrif fóðrunar á blóðelhi. Ráðunautafundur 1995. 103-110.
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period. 2. Metabolic and hormonal responses. J. Dairy Sci. 86, 883-891.
Holtenius, P., 1994. The metabolic capacity, a factor of importance for thealth and production in dairy
cows. XVII Nordic Vet. Congress 26-29 july 1994, Reykjavik, Iceland. 185-189.
Ingvartsen, K.L., Aaes, O., Andersen, J.B., 2001. Effects ofpattem of concentrate allocation in the dry
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