Change of feeding during conversion: Implications for animal health S6
Sundrum, Albert1; Weller, Richard2; Aston, Keith2; Riesen, Guido3; Andersson, Robby3, Köpke, Ulrich1
1) Institute of Organic Agriculture, Faculty of Agriculture, D-53115 Bonn, Germany 2) Institute of Grassland and Environmental Research, Aberystwyth, Dyfed, SY23 4LL, Wales 3) Institute of Animal Hygiene, Faculty of Agriculture, D-53115 Bonn, Germany
|Conversion from conventional to organic
agriculture is accompanied by changes in the feeding regime of dairy cows, involving among
other changes to a restriction in the amount of concentrate and to an enhancement in the
portion of legumes in the diet. As a result, energy and crude protein supply can deviate
widely from the requirements of the animal. Investigations were carried out during the
winter and summer season to assess the effect of unbalanced diets on animal health.
Biochemical and immunological blood parameters were used as indicators.In the first
experiment (winter period) 40 cows were divided into two groups fed both a clover/grass
silage-based diet, supplemented with 3 kg DM rolled faba beans from the 2nd to the 6th
week after parturition. The control group was given concentrate additionally consisting of
2.0 kg barley, 0.9 kg soya beans and 0.2 sugar beet pulp. Blood samples were drawn in the
2nd, 4th and 6th week after parturition. Results showed that the different diets had no
significant effect on the milk yield. Neither the concentration of urea, aspartate
aminotransferase, cholesterol, protein and immunoglobulin G in the plasma nor the number
of leucocytes and the bactericidal activity in the whole blood were influenced by the diet
within the experimental phase. In the second experiment (spring period) the effect of
changing from indoor to outdoor conditions and changing from grass-based to
clover-enriched swards was assessed in relation to animal health parameters in a herd of
42 cows. While the concentration of urea, aspartate aminotransferase, glucose,
cholesterol, total protein and immunoglobulin G in the plasma remained unchanged,
bactericidal activity in the whole blood clearly increased when cows were put to pasture.
In the following phase the herd was divided into two groups and put on either
clover-enriched or grass-based swards. Cows on the clover-enriched sward showed
significantly higher urea levels in the plasma compared to cows on a grass-based sward
whereas other biochemical parameters were not influenced. It could be concluded that a
reduced amount of concentrate in early lactation as well as a high clover portion in the
sward can be compensated for by dairy cows without showing signs of health disorders.
Acknowledgement The authors wish to thank the Commission of the European Union for financial support.