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Abstract preview
EGF 2008
Does effect of selection history influence the cattle’s vegetation and plant
preferences?
Sæther N. 1, Sickel H. 2, Norderhaug A. 3, Sickel M. 4 and Vangen O. 5
1
Norwegian Genetic Resource Centre, N-1432 Ås, Norway
2
Norwegian Institute for Agricultural and Environmental Research, Løken, N-2940
Heggenes, Norway
3
Norwegian Institute for Agricultural and Environmental Research, Kvithamar, N-7500
Stjørdal, Norway
4
Norwegian Radiation Protection Authority, N-1332 Østerås, Norway
5
Norwegian University of Life Sciences, Department of Animal and Aquacultural Science, N1432 Ås, Norway
Corresponding author: [email protected]
Abstract
In this project plant and vegetation preferences of two Norwegian dairy cattle breeds with
different selection history were studied. The Norwegian dairy breed Blacksided Trønder and
Nordland Cattle (STN) has never been selected efficiently for higher milk production. The
other breed, however, the Norwegian Red (NR), has mainly been selected for this. Two herds
both consisting of STN and NR cows, were studied. To examine the animals’ plant
preferences, faeces samples were collected and analysed for plant fragments. Vegetation maps
were also used to find possible differences in grazing preferences. Breed differences with
regard to recorded plant fragments in the faeces samples were significant for Nardus stricta,
a species characteristic for nutrient poor but mostly species rich vegetation types in the
studied areas, vegetation types of high importance for the biodiversity especially in one of the
areas. STN had the highest share of Nardus stricta. Altogether the results of the study indicate
that a higher producing cattle breed might prefer to graze more nutrient rich vegetation areas
compared to a lower yielding cattle breed, when grazing less nutrient and base rich - but
species rich grasslands.
Keywords: semi-natural grasslands, grazing, cattle, breed differences, vegetation preferences
Introduction
The areas of species rich semi-natural grasslands have been considerably reduced during the
last 50 years in Norway. Maintenance of these valuable habitats depends on traditional use or
special management to prevent regrowth succession and loss of species (Norderhaug et al,
1999; Sickel et al, 2004). A survey conducted by Sæther & Vangen (2001) revealed that
farmers utilizing the low yielding Norwegian dairy breed STN expected this breed to utilize
extensive grasslands better than cows of the high yielding NR. Approximately 97 % of
Norwegian dairy cattle are NR, while 0.1 % belongs to the STN breed. Average yearly milk
yield for the two breeds are 6, 200 kg and 4, 000 kg, respectively. Several studies have shown
that breeds and/or lines selected for high production intensity generally show lower levels of
activity, for references see Sæther et al (2006). Furthermore, when given the choice between
hardly and easily accessible fodder, they tend to choose easily accessible fodder at a higher
rate than breeds and lines not selected for the same high production intensity. This study
therefore addresses the following question: Will genetic high yielding cows focus more on
nutrient rich plant species and vegetation types than genetic low yielding cows when grazing
extensive, species rich semi-natural grasslands?
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Abstract preview
EGF 2008
Materials and methods
Two dairy cattle herds, one farm in Skåbu and and one farm in Valdres, were studied. Both
farms have long, continuous summer farming traditions based on semi-natural grasslands in
the mountains. The herds had nine purebred cows each, five and six STN cows, and four and
three NR cows, respectively. The dominating bedrocks in Skåbu are base-rich bedrocks with a
high weathering capacity, giving rise to nutrient and base rich soils. In Valdres the bedrock
consists entirely of a less basic phyllite type, and the soils are poorer than in Skåbu. Today the
studied areas have a low grazing pressure. The nomenclature for plants follows Lid & Lid
(2005). On average the herds on each farm were observed 9 hours daily, with a span of 7-13
hours per day, during one week in July and one in August. In total, 49 faeces samples were
randomly collected across weeks, study sites and animals and prepared for microhistological
analyses, following the procedures of Garcia-Gonzalez (1986). Fragments from 28 plantspecies, -genera and -groups, were found in the faeces samples, however, only the 14 with
higher mean values than 2 % of total recorded fragments are included in the statistical
analyses. In the statistical analysis the possible effects of breed (STN & NR), farm (Skåbu &
Valdres) and month (July & August) are included as fixed effects together with the interaction
breed * farm. The effect of cow within breed is included as a random effect to adjust for
variation between individuals within breed.
Results and discussion
Both study sites had species rich grasslands. In total, 123 species were found. Of these, 51
species were only found in Skåbu and 20 species only in Valdres. The most common
grassland vegetation type in Valdres was characterised by many common and small-sized
grasses and herbs with low to medium demands of base rich soil. Nardus stricta and other
drought-resistant species often grew on the top of small elevations, while species indicating
better moisture conditions, e.g. certain Carex species, dominated on lower and more humid
parts of the grasslands. Vaccinium myrtillus was also often found here. Another grassland type
found in the Valdres area is dominated by Nardus stricta as a result of too heavy grazing for
many years. The vegetation in Skåbu was characterised by many base demanding species.
Forests, protecting small elevations and knolls against wind and drought, surrounded the
grasslands. Thus, moisture conditions and the distribution of plant species in the grasslands
were more uniform here.
The results from the microhistological analyses showed that the cows had most grass
fragments (76 %). In addition to a group of unidentified grass species, 13 grass species and
genera were recognised. Avenella flexuosa (25 %) and Deschampsiacespitosa (15 %)
dominated. Also several herbs and Carex spp. are valuable grazing plants. Together herbs and
Carex spp. constitute almost 16 % of the observed fragments. Only the dominating grazed
grass species, and the species or plant groups contributing significantly to the interpretation of
the results, are included in the statistical analysis presented below.
Table 1. Results from the statistical analyzes on the plant fragment residues observed in the
faeces samples. The figures are given as percentage of total fragments.
Plant species, genera or
group
Vaccinium myrtillus
Nardus stricta
Carex spp
Total grass
Deschampsia cespitosa
Avenella flexuosa
Farm
**
**
**
**
**
**
Breed
*
-
LSLSLSLSInteraction Average means means means means
STN
NR
Skåbu Valdres
Month Farm/breed value
*
2.0
1.8
2.1
2.8
1.3
3.8
5.1
3.8
1.7
7.2
8.4
8.4
9.5
4.4
13.5
**
76.1
77.7
75.8
74.0
79.4
25.5
27.0
25.1
19.3
32.9
**
15.1
15.0
14.9
19.8
10.2
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Abstract preview
EGF 2008
Table 1 shows that the effect of breed was only significant for Nardus stricta, a species
characteristic for nutrient poor but mostly species rich vegetation types in the studied
areas. The STN breed had a higher share of Nardus stricta fragments in the faeces samples
than the NR breed. The interaction between farm and breed was significant for Vaccinium
myrtillus and the plant group “total grass”. The effect of farm was significant for all tested
species and plant groups; however, within farm the results showed that when grazing in areas
with nutrient and base rich soil and species rich vegetation types, as in Skåbu, the two breeds
mostly graze the same vegetation and plant species. In Valdres, however, where the soil is
less fertile, and the plant species distribution less uniform than in Skåbu, the results indicate
that the NR cows graze more in patches where Carex spp. grow than the STN cows. STN also
graze more Carex spp. in Valdres than in Skåbu, but the increase is less than for NR. Both
breeds graze less Vaccinium myrtillus in Valdres, but NR decrease less than STN. In Valdres
Vaccinium myrtillus occur in the same vegetation type as some Carex spp. that are defined as
valuable grazing plants (Rekdal 2001). Studies by Garmo (1986) state that Carex spp have a
higher content of crude protein and less content of crude fibre than grass species during the
entire grazing season, indicating that Carex spp in general have a higher nutrient value than
grass. This may explain why NR cows seem to graze more in patches where Carex spp. grow
and Vaccinium myrtillus occur. Both breeds graze more Nardus stricta in Valdres than in
Skåbu, probably because this species is more common in Valdres. This grass species has low
digestibility and stiff, narrow leaves. It is therefore not seen as a valuable or preferred grazing
species. It may, however, be grazed to a certain extent when it occurs in vegetation types
preferred by the grazing cattle. STN has a higher increase in Nardus stricta than NR,
indicating that the STN cows graze more in nutrient poor but species rich areas where this
species is common in Valdres.
Conclusions
Results from this study indicates that a cattle breed selected for high milk yield might prefer
to graze more nutrient rich vegetation areas compared to a lower yielding cattle breed, when
grazing less nutrient and base rich but species rich grasslands. When managing semi-natural
grasslands, the effect of grazing therefore might be different when choosing a low instead of a
high yielding dairy cattle breed. This possible difference ought to be taken into consideration
when managing extensive grasslands as loss of biodiversity by re-growth of less nutrient rich
but species rich vegetation types seems to be smaller when using a lower yielding breed.
References
Garcia-Gonzales, R. 1984. L‘emploi des épidermis végétaux dans la detremination du regime alimentaire de
l’isard dans le Pyrénées occidentales. Documents d’Ecologie Pyrénéenne, 3-4:307-313.
Garmo, T. H. 1986. Chemical composition and in vitro digestibility of indigenous mountain pasture plants in
different plant groups (Preliminary report). Rangifer, 6 (1): 14-22.
Lid, J & Lid, D.T. 2005. The Norwegian Flora. Det Norske Samlaget 7 . edition by Reidar Elven (ed.).
Norderhaug, A., Austad, I., Hauge, L. & Kvamme, M. (ed). 1999. The book of management for cultural
landscapes in Norway.
Sickel, H., Ihse, M., Norderhaug, A. & Sickel, M. 2004. How to monitor semi-natural key habitats and grazing
preferences of cattle in mountain summer farming areas. An aerial photo and GPS method study. Landscape and
Urban Planning 67 (2004): 67-77.
Sæther, N. H. and Vangen, O. (2001) Motives for utilizing the Blacksided Trønder and Nordland: A native cattle
breed in Norway. Animal Genetic Resources Information 31, 15-26.
Sæther N.H., Sickel H., Norderhaug A., Sickel M. and Vangen O., (2006) Plant and vegetation preferences for a
high and a moderate yielding Norwegian dairy cattle breed grazing semi-natural mountain pastures. Anim.Res.
55, pp 367-387.
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