Nötkreaturens val av betesvegetation på naturliga betesmarker
This study concerns the type of vegetation selected by cattle grazing on semi-natural pastures, and whether the selection depends on the nutrient content of the vegetation or on other factors.
The study was carried out in three different semi-natural pastures in the Uppsala area during June, July and August in 2006. The three pastures were first surveyed, mapped out and divided into sub-areas with regard to the type of dominating vegetation. The vegetation types identified were: wet, mesic, dry, wooded, pasture with signs of former cultivation (arable). Within each vegetation type three 1x1 m sampling plots were laid out.
The grazing behaviour of the cows was recorded in a behaviour study. In each pasture area behaviour observations were performed during three days each month (June-August). The animals were followed during four hours of grazing activity every observation day and notes were made every five minutes as to where in the meadow the animals grazed and what type of vegetation they chose. Samples of the vegetation grazed were taken every five minutes for analysis.
The animals chose to graze on sub-areas with arable pasture in more than 50% of the observation occasions. The amount of observations made on arable pasture sub-areas was very large compared to their proportion of the entire pasture area. This preference for arable pasture was probably caused by the higher nutritive content of the herbage on these pasture areas, compared with the nutritive content of the herbage from areas dominated by other vegetation types. The contents of energy, organic substance and crude protein in the herbage from these sub-areas were the highest, and the fibre content was lowest. However, to some extent the observations of high grazing activity on arable pasture land could also be explained by the fact that in two of the pastures, minerals and water troughs were placed on a sub-area with arable pasture.