Epsilon Archive for Student Projects

Abstract

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.

Denna studie undersökte huruvida nötkreaturs betesval på naturliga betesmarker styrdes av vegetationens näringsinnehåll, eller av andra faktorer.
Studien genomfördes i tre olika hagar i Uppsalaområdet under juni, juli och augusti 2006. Hagarna karterades och uppdelades i olika områden beroende på vilken vegetationstyp (torrt, frisk-torrt, friskt, blött, skog, gammal f.d. åker, ny f.d. åker eller övrigt) som dominerade i området. Provytor lades ut i varje vegetationstyp för att förbereda provtagning under säsongen. Betesbeteendet undersöktes i en beteendestudie där djuren observerades tre dagar per månad under juni-augusti under fyra timmars bete (aktivt betande) per dag. Var femte minut gjordes noteringar av var i hagen djuren befann sig, samt vilken typ av vegetation de betade. Var femte minut togs också prover av den vegetation som djuren betade just då. Även vädret under observationsdagarna noterades.
Djuren valde i mer än hälften av fallen att beta på gammal eller ny f.d. åkermark. Betesaktiviteten på dessa ytor var mycket stor i jämförelse med hur stor andel av hagen som åkermarken utgjorde. Preferensen för f.d. åkermark berodde förmodligen på de höga näringsvärden som betet på denna vegetationstyp hade jämfört med betet på de andra vegetationstyperna: betet uppvisade hög smältbarhet (VOS), mineralinnehåll (aska) och råproteinvärden, samt låga fibervärden (NDF). Till viss del kan betesaktiviteten dock troligen även förklaras med att vatten och mineraler fanns tillgängliga på just f.d. åkermark i två av de tre hagarna.