1751-0147-42-31 1751-0147 Original article <p>Plants as De-Worming Agents of Livestock in the Nordic Countries: Historical Perspective, Popular Beliefs and Prospects for the Future</p> Waller PJ Bernes G Thamsborg SM Sukura A Richter SH Ingebrigtsen K Höglund J

Dept. Parasitology (SWEPAR), National Veterinary Institute, Uppsala, Sweden

Dept. Agric. Research Nth. Sweden, SLU, Umeå, Sweden

Dept. Anim. Science and Animal Health, The Royal Veterinary and Agricultural University, Frederiksberg, Denmark

Dept. Basic Vet. Science, Univ. Helsinki, Finland

Inst. Exp. Pathology, Univ. Iceland, Keldur, Reykjavik, Iceland

Dept. Pharmacology, Microbiology and Food Hygiene, Norwegian School Vet. Medicine, Oslo, Norway

SWEPAR, Swedish University of Agricultural Sciences, Uppsala, Sweden

 Acta Veterinaria Scandinavica 1751-0147 2001 42 1 31 44 http://www.actavetscand.com/content/42/1/31 11455900 10.1186/1751-0147-42-31 05 6 2000 08 9 2000 31 3 2001 plant anthelmintics herbal remedies helminth parasites livestock man

Preparations derived from plants were the original therapeutic interventions used by man to control diseases (including parasites), both within humans and livestock. Development of herbal products depended upon local botanical flora with the result that different remedies tended to develop in different parts of the world. Nevertheless, in some instances, the same or related plants were used over wide geographic regions, which also was the result of communication and/or the importation of plant material of high repute. Thus, the Nordic countries have an ancient, rich and diverse history of plant derived anthelmintic medications for human and animal use. Although some of the more commonly used herbal de-wormers were derived from imported plants, or their products, many are from endemic plants or those that thrive in the Scandinavian environment. With the advent of the modern chemotherapeutic era, and the discovery, development and marketing of a seemingly unlimited variety of highly efficacious, safe synthetic chemicals with very wide spectra of activities, herbal remedies virtually disappeared from the consciousness – at least in the Western world. This attitude is now rapidly changing. There is a widespread resurgence in natural product medication, driven by major threats posed by multi-resistant pest, or disease, organisms and the diminishing public perceptions that synthetic chemicals are the panacea to health and disease control. This review attempts to provide a comprehensive account of the depth of historical Nordic information available on herbal de-wormers, with emphasis on livestock and to provide some insights on potentially rewarding areas of "re-discovery" and scientific evaluation in this field.

Introduction

The use of plants, or their extracts, for treatment of gastro-intestinal parasites in humans and livestock is steeped in antiquity. It was Claudius Galënus (AD 130–200), a Greek physician of Pergamon, who received notoriety for applying medicines prepared from vegetable substances by infusion, or decoction. These became known generically as "galenical" drugs, or preparations, and established the foundation for modern veterinary pharmacology. It is with some interest to note that the approach taken by Galënus was in contrast to the Hippocrates/Paracelsus school of thinking which espoused treating "like with like" (similia similibus curantur), that later formed the basis for Hahneman's concepts of homeopathy 68.

In medieval times, plants with reputed anthelmintic properties were often mixed with mineral salts (arsenic, copper etc.), or more esoteric materials (blood, faeces, fluids from reptiles, wild animals etc.) to form quite bizarre and often hazardous concoctions – for both parasites and hosts alike. With time, trial and error, such preparations were refined in an attempt to at least moderate the undesirable consequences to the host, but with the advent of safer and more effective synthetic anthelmintic compounds, they rapidly disappeared from the veterinary anthelmintic market 26. Nevertheless, it is of interest to note that the World Health Organisation has recently estimated that 80% of the population of developing countries rely on traditional medicine, mostly plant drugs, for their primary health care needs (12). Also in a global context, modern pharmacopoeia still contain in the order of 25% drugs derived from plants and many others which are synthetic analogues built on prototype compounds isolated from plants.

However, there has been a resurgence of interest in traditional health practices throughout the world. In veterinary medicine, this interest encompasses ethnobotany and the use of herbal remedies. Workshops, forums and conferences are occurring with increasing regularity, which is obviously being driven by a concomitant increasing level of research acitvity. The forces responsible for this momentum are manifold. These include the perception that "natural is nice", concerns of synthetic drug residues in the environment and the food chain, and particularly the spectre of rapid emergence of multiple resistant pest organisms through misuse and overuse of these modern drugs.

Within the Nordic countries, the same holds true. This region of the world is at the vanguard of the organic farming movement, with major emphasis on livestock production. Many progressive and educated farmers who have chosen to farm livestock organically are well aware of the importance of nematode parasites affecting the productivity of their animals and adopt grazing strategies aimed at evading, or mitigating the effects of parasites in their animals 62. However, others show less awareness and management of grazing livestock is largely determined by herbage supply and not by parasitological considerations 69. One specific strategy is to graze livestock on plants with purported anthelmintic properties. For example, a survey of Danish organic dairy farmers with 255 respondents, revealed the use of herbs in the leys on 26% of the farms. Of these, caraway (Carum carvi) [56%], parsley (Petroselinum crispum) [20%], chicory (Cichorium intybis) [10%], chervil (Anthriscus cerefolium) and dill (Anethum graveolens) [14%], used singly or in combination, were the most commonly used plants 58. For the purposes of deworming, the feeding of wormwood (Artemisia absinthium), mugwort (A. vulgaris), chicory (Cichorium intybis) and common tansy (Tanacetum vulgare) were expected by farmers to have anthelmintic properties 58.

In addition, there has been a major commitment to the development of sustainable disease control systems, which by definition means the integration of a range of non – chemical methods with the minimal use of drugs, to insure continued effectiveness for the foreseeable future. Control of internal parasites of livestock by these means has been a major focus of research activities in the Nordic countries for several years 65.

Research in the Nordic countries on anthelmintic properties, or protective effects, of local plants against helminth parasites of livestock is very recent and limited at this stage to studies on tanniferous forages 396. However, many of the earliest written reports of anthelmintic properties of plants originate from this region of the world (eg., the writings of Henrik Harpestræng in the early 13th century). The purpose of this review is to provide a historical perspective and to present our view of the potential and possibilities for the use of plants that are endemic, or thrive in the Nordic environment, as de-worming agents. Due to the relatively wide variation in climate, soil, altitude etc. within this limited area, the total number of plant species is quite large.

Also, a brief consideration is made of the recent developments in the use of specialized crops, the so-called "nutraceuticals", which are bioactive crops that are either grazed, or fed after preservation, with the main purpose of preventing or curing disease. The ultimate objective would be to use these plants as additional means for the further development and refinement of sustainable parasite control systems of livestock.

Plants and parasites

There is an inextricable association between plants and parasites of livestock. Pastures provide the link between the free-living and the parasitic phases of helminth parasites for all grazing animals. At different stages of growth, pasture species may facilitate or impede the survival of free-living populations, the establishment of parasite burdens and lessen or intensify the effects of parasitism on the host. Competent management of pastures is needed for the twin goals of efficient conversion of herbage to animal products and effective control of gastrointestinal parasites.

Indirect effects of plants on parasites

It is reasonable to assume that the height, density and form of plant growth could affect the micro-environment of the free-living stages of parasites and thus play a role in transmission of infection. Because of the necessity of moisture films for movement of nematode larvae from faecal deposits to herbage, it might be expected that pastures consisting largely of erect, tall growing species would provide less protection from desiccation, and from removal by heavy rain, than those consisting primarily of prostrate species. Indeed, a factor considered to mitigate the high rates of contamination following increased stocking rates is the decreased availability of herbage, which provide conditions less favourable for the development and survival of the free-living stages of nematode parasites 64. Although there has been a number of such ecological studies, little has been done in the Nordic countries and this aspect is outside the scope of this review. However, it is important to recognise these indirect effects of herbage when any grazing studies are conducted on plants with purported anthelmintic properties. It must be established that observed effects are directly plant related and not due to effects on development and survival of the free living stages of parasites, or the provision of an enhanced level of nutrition which helps the animal to rapidly mount an immune response against incoming or resident parasite infections.

Direct effects of plants on parasites

This relates specifically to anthelmintic properties of plants. Although there is a large and diverse range of herbal de-wormers that are used throughout the world, particularly in the Asian and African countries, generally there is a lack of scientific validation of the purported anthelmintic effects of these products. Evidence to date is almost entirely anecdotal. This also applies to the reports of de-worming properties of herbal preparations that have either Nordic origins, or a long history of use in this region (for some historical background, see 27). These can be broadly classified into the following classes (see Table 1):

<p>Table 1</p>

Plants said to have been used against internal parasites in the Nordic countries; their scientific names and names in English and in the Nordic languages.

Plant family

Scientific name

English

Swedish

Norweigan

Danish

Finnish

Icelandic

Host

Target

Part used

Reference

Lichens

Cetraria islandica

Iceland moss

islandslav

islandslav

lav *

jäkälä

fjallagrös *

M

H

W

8, 9, 33, 36,

37, 41

Ferns

Dennstaedtiaceae

Pteridium aquilinum

bracken fern

örnbräken *

einstape *

ørnebregne *

sananjalka *

arnarburkni

M

H,C

R

9, 21, 35, 45

Dryopteridaceae

Dryopteris carthusiana

toothed wood fern

skogsbräken

broddtelg

Smalbladet mangeløv

metsäalvejuuri *

31

D. expansa

spring wood fern

nordbräken

sauetelg

Finbladet mangeløv

isoalvejuuri *

flekkaburkni

31

D. filix-mas

male fern

träjon *

ormetelg *

Almindelig mangeløv *

kivikkoalvejuuri *

stóri burkni *

M,A,S,H

H,N,C,T

R

4, 5, 8, 9, 10, 30, 31, 33, 35, 44, 45, 53, 54, 70

Polypodiaceae

Polypodium vulgare

polypody

stensöta *

sisselrot

engelsød

kallioimarre *

köldugras

M

H,C

R

45, 49

Coniferous trees

Pinaceae

Picea abies

spruce

gran

gran *

rødgran

kuusi *

rau∂greni

M,A

H

J

29, 55

Pinus sylvestris

pine

tall *

furu

skovfyr

mänty *

skógarfura

M

C

H,P,T

45, 49

Cupressaceae

Juniperus communis

juniper

en *

einer *

enebær *

kataja *

einir *

M,A,C,H

H,N,C

B,R,P

9, 14, 25, 34, 44, 45, 53

J. sabina

savin

sävenbom

sevenbom *

rohtokataja

sabínueinir

C,H,P

W

9

Trees, shrubs

Salicaceae

Populus tremula

aspen

asp

osp *

bævreasp

haapa *

ösp

M,H

H,N,C

L,P

34, 45

Salix spp

willow

sälg

vier

pil *

paju *

vi∂ir *

M,S,H

H,C,T

L,P

9, 33, 45

Myricaceae

Myrica gale

sweet gale

pors

pors *

porse *

suomyrtti

mja∂arlyng

M,H

H

W,L,F

9, 35

Betulaceae

Alnus glutinosa

alder

al

or

el *

tervaleppä

rau∂elri

S

T

H

9

Betula pendula

silver birch

vårtbjörk

hengebjørk

vorte-birk

rauduskoivu *

M

C

L,J,P

45

B. pubescens

downy birch

glasbjörk

bjørk

dun-birk *

hieskoivu *

birki *

M,S

H,C

L,J,P,C

9, 33, 37, 45, 50

Corylaceae

Corylus avellana

hazel bush

hassel

hassel

hassel *

pähkinäpensas

heslivi∂ur

H

L

9

Grossulariaceae

Ribes nigrum

blackcurrant

svarta vinbär

solbær

solbær

musta viinimarja *

sólberjarunni

M

C

B

45

R. rubrum

redcurrant

röda vinbär

hagerips

ribs *

punainen viinimarja

rifs

M

9

Rosaceae

Prunus padus

bird cherry

hägg

hegg

hæg

tuomi *

heggur

M

C

B,P

45

Pyrus communis

pear

päron

pære

pære *

päärynä

perutré

S

N

O

9

Sorbus aucuparia

rowan

rönn

rogn

røn

pihlaja *

reynir

M

C

P

45

Buxaceae

Buxus sempervirens

boxwood

buxbom

buksbom

buksbom *

puksipu

fagurlim

H

L

9

Rhamnaceae

Frangula alnus

buckthorn

brakved

trollhegg

tørst

paatsama *

porstatré

M

C

P

45, 53

Thymelaeaceae

Daphne mezereum

mezeron

tibast

tysbast *

pebertræ

näsiä *

töfratré

M

H,C

B,P

34, 35, 45, 55

Oleaceae

Fraxinus excelsior

ash tree

ask *

ask

ask

saarni *

askur

M

H,C

L,P

45, 49

Caprifoliaceae

Sambucus nigra

black elder

fläder

svarthyll

hyld *

selja *

svartyllir

M,S

C,T

B

9, 45

Herbaceous plants

Cannabaceae

Humulus lupulus

common hops

humle *

humle

humle *

humala *

humall

M,S

H,C,T

W,R,C

9, 45, 49

Urticaceae

Urtica dioica

stinging nettle

brännässla *

stornesle

stor nælde *

nokkonen

stórnetla

M,S

H,T

W,S

9, 23, 44, 49

U. urens

small nettle

etternässla

smånesle *

liden nælde

rautanokkonen

brenninetla *

M

H

W,S

41, 55

Polygonaceae

Rumex acetosa

green sorrel

ängssyra

engsyre

rødknæ *

suolaheinä *

túnsúra

M,P

H,C

L,F,R

9, 45

Chenopodiaceae

Chenopodium ambrosioides

goosefoot

citronmålla

melde

gåsefod

savikka *

31

C. bonus-henricus

good king Henry

lungrot *

stolt henrik

stolthenriks-gåsefod

hyvänheikinsavikka

hinriksnjóli

M

H,C

W

49

C. rubrum

red goosefoot

rödmålla *

rødmelde

rød gåsefod

punasavikka

M

H

W

49

Portulacaceae

Portulaca oleacea

Common purslane

portlak *

portulakk

portulak

vihannesportulakka

portúlakka

M

H

W

44

Caryophyllaceae

Agrostemma githago

corncockle

klätt

klinte

klinte *

aurankukka

akurstjarna

M

9

Ranunculaceae

Hepatica nobilis

hepatica

blåsippa

blåveis

anemone *

sinivuokko

blá-anemóna

M

9

Fumariaceae

Corydalis intermedia

corydalis

smånunneört *

lerkespore

lærkespore

hentokiurunkannus*

M

H,C

R

45, 49

Fumaria officinalis

Common fumitory

jordrök *

jordrøyk

læge-jordrøg

peltoemäkki

reykjurt

M

C

W

20

Brassicaceae

Armoracia rusticana

horseradish

pepparrot

pepperrot

peberrod *

piparjuuri

piparrót *

H

H

R

9, 41

Brassica spp

cabbage

kål *

kål

kål *

kaali, nauris *

kál

M

H, C

S, R

9, 44, 45

Cardamine hirsuta

hairy bitter-cress

ängsbräsma

rosettkarse

roset springklap

mäkilitukka

lambaklukka *

H

L

8, 36, 37

C. pratensis polemonioides

cuckooflower

polarbräsma

polarkarse

polarkarse

pohjanlitukka

hrafnaklukka *

M

H

L

33, 41

Descurainia sophia

flixweed

stillfrö *

hundesennep

finbladet vejsennep

liitutilli *

þefjurt

M

H,N,C

S

22, 45, 49

Lepidium sativum

garden cress

kryddkrasse *

matkarse

karse *

vihanneskrassi

karsi

M,S

H,T

W,S

9, 44

Raphanus sativus niger

garden radish

rättika *

reddik

ræddike *

retikka

radísa

C,H

H

R

9, 44

Sisymbrium officinale

hedge mustard

vägsenap

vegsennep

vejsennep *

rohtopernaruoho

götudesurt

M

9

Crassulaceae

Rhodiola rosea

roseroot

rosenrot

rosenrot *

rosenrod

ruusujuuri

burnirót

C

H

R

55

Sempervivum tectorum

house leek

taklök *

takløk

husløg *

mehitähti

húslaukur

M

C

W

9, 44

Rosaceae

Agrimonia eupatoria

agrimony

småborre *

åkermåne

agermåne *

maarianverijuuri

M

H

W

9, 44, 49

Fragaria vesca

Wood strawberry

smultron

markjordbær

skov jordbær *

mansikka *

villijar∂arber

M

C

B

9, 45

Potentilla anserina

silverweed

gåsört *

gåsemure

gåse-potentil

ketohanhikki

tágamura

M

H

W

44

P. erecta

tormentil

blodrot *

tepperot

tormentil *

rätvänä

bló∂mura

M,S

H,T

W,R

9, 44

Rubus chamaemorus

cloudberry

hjortron

molte

multebær

lakka *

múltuber

M

C

B

45

R. idaeus

red raspberry

hallon

bringebær

hindbær *

vadelma *

hindber

M

C

B

9, 45

Sanguisorba officinalis

great burnet

blodtopp *

blodtopp

læge kvæsurt

punaluppio

bló∂kollur

H

H

R

30

Fabaceae

Vicia sativa

common vetch

fodervicker

fôrvikke

vikke *

vikkeri

fó∂urflækja

H

W

9

Rutaceae

Ruta graveolens

common rue

vinruta

vinrute

rude *

ruutakasvi

rú∂ujurt

M

9

Clusiaceae

Hypericum perforatum

Perforate St.John's-wort

Äkta johannesört *

prikkperikum

Prikbladet perikon *

mäkikuisma

jónsmessurunni

M

H

F,H

9, 49, 51

H. maculatum

Imperforate St.John's-wort

Fyrkantig johannesört

firkant-perikum

kantet perikon

särmäkuisma *

flekkjagullrunni

M

C

45

Violaceae

Viola odarata

sweet violet

luktviol

marsfiol

marts-viol *

tuoksuorvokki

ilmfjóla

M

9

Cucurbitaceae

Cucumis sativus

cucumber

gurka

agurk

agurk

kurkku *

agúrka

M

C

S

45

Cucurbita pepo

pumpkin

Pumpa

gresskar

mandel-græskar *

kurpitsa *

grasker

M

N,C

S

9, 45

Apiaceae

Anethum graveolens

dill

dill

dill

dild *

tilli

dill

C

9

Angelica archangelica

angelica

kvanne

kvann

kvan

väinönputki

hvönn *

M,H

H

S,R

8, 32, 33, 36, 37, 41

Anthriscus cerefolium

chervil

dansk körvel *

hagekjørvel

kørvel *

maustekirveli

gar∂akerfill

M

H

W

9, 44

Apium graveolens

celeriac

selleri

hageselleri

selleri *

selleri

bla∂selja

M

9

Carum carvi

caraway

kummin

karve *

kommen *

kumina *

kúmen

M

H,C

W,S

9, 34, 45

Coriandrum sativum

coriander

koriander

koriander

koriander *

korianteri

kóriandra

M

9

Daucus carota

carrot

morot *

gulerot *

gulerod *

porkkana *

gulrót

M,P

H,C

R

9, 35, 44, 45, 49, 55

Foeniculum vulgare

fennel

fänkål

fennikel

fennikel *

fenkoli

fennikka

S

T

9

Levisticum officinale

lovage

libbsticka *

løpstikke

løvstikke *

liperi

tröllatrygg∂

M

H

S

9, 44

Petroselinum crispum

parsley

persilja

persille

persille

persilja *

steinselja

C

P

29

Ericaceae

Calluna vulgaris

heather

ljung *

røsslyng

lyng *

kanerva

beitilyng

S

T

9, 49

Vaccinium myrtillus

blueberry

blåbär

blåbær

blåbær

mustikka *

a∂albláberja-lyng

M

C

B

45

V. oxycoccos

cranberry

tranbär

tranebær

tranebær

karpalo *

M

C

B

45

V. uligunosum

bog bilberry

odon

blokkebær

mosebølle

juolukka *

bláberjalyng

M

C

B

45

V. vitis-idaea

lingonberry

lingon

tyttebær

tyttebær

puolukka *

rau∂berjalyng

M

C

B

45

Gentianaceae

Centaurium littorale

Seaside centaury

kustarun

tusengylden

tusingylden*

isorantasappi

köldublóm

H

9

Gentianella campestris

field gentian

fältgentiana

bakkesøte

Bredbægret ensian

ketokatkero

maríuvöndur *

H

H

R

8, 32, 33, 36, 37

Menyanthaceae

Menyanthes trifoliata

marsh trefoil

vattenklöver *

bukkeblad *

bukkeblad *

raate *

horbla∂ka *

M,S,H,P

H,C,T

W,L,R

4, 8, 9, 32, 33, 36, 37, 41, 45, 52, 55

Verbenaceae

Verbena officinalis

vervain

läkeverbena *

jernurt

jernurt

tarhaverbana

járnurt

M

H

W,F

44

Lamiaceae

Glechoma hederacea

ground-ivy

jordreva

krossknapp

korsknap *

maahumala

krosshnappur

H

W

9

Hyssopus officinalis

hyssop

isop *

isop

isop *

iisoppi

isópur

M

H,N

W

9, 44

Leonurus cardiaca

motherwort

hjärtstilla

løvehale

Almindelig hjertespand*

nukula

M

9

Melissa officinalis

lemon balm

citronmeliss

sitronmelisse

hjertensfryd*

sitruunamelissa

hjartafró

C

9

Mentha crispa

mint

krusmynta *

kattemynte

mynte *

minttu

M

N

W

9, 44

Nepeta cataria

catnip

kattmynta *

lækjekatte-mynte

katteurt *

aitokissanminttu

kattarmynta

M

H

W

9, 44

Origanum vulgare

wild majoram

kungsmynta

bergmynte

Almindelig merian *

mäkimeirami

kjarrmynta

M

9

Salvia spp

sage

salvia

salvie

salvie *

salvia

salvía

S

T

W

9

Thymus serpyllum

wild thyme

backtimjan *

kryptimian

Smalbladet timian

kangasajuruoho

bló∂berg

M

H

W

38

T. vulgaris

garden thyme

trädgårds-timjan *

kryddertimian

havetimian

timjami *

gar∂abló∂berg

M

H,C

W

38, 45

Solanaceae

Hyoscyomus niger

henbane

bolmört

bulmeurt

bulmeurt *

hullukaali

skollarót

H

S

9

Nicotiana rustica

small tobacco

tobak

tobakk

tobak *

tupakka

bónda-tóbaksjurt

S

T

R

9

Solanum dulcamara

Woody nightshade

besksöta

slyngsøtvier

Bittersød natskygge *

punakoiso

eiturflækja

M

9

S. nigrum

Black nightshade

nattskatta

svart søtvier

Sort natskygge *

mustakoiso

húmjurt

H

L,B

9

S. tuberosum

potato

potatis

potet

kartoffel

peruna *

kartafla

M

C

R

45

Scrophulariaceae

Rhinanthus spp

yellow rattle

skallra

kall

skjaller *

laukku

lokasjó∂ur

M

9

Veronica anagallis-aquatica

blue water speedwell

vattenveronika

vassveronika

Lancetbladet ærenpris

konnantädyke

laugadepla *

M

H

W

8, 36, 37

V. chamaedrys

Germander speedwell

teveronika *

tveskjegg-veronica

Tveskægget ærenpris

nurmitädyke

völudepla

M

H

W

44

Planataginaceae

Plantago lanceolata

English plantain

svartkämpar

smalkjempe *

lancet-vejbred

heinäratamo

selgresi *

M

H

L,R

8, 33, 35, 36, 41

P. major

great plantain

groblad

groblad *

vejbred *

piharatamo

græ∂isúra *

M

H

W,L,R

9, 35, 37, 41, 55

P. maritima

sea plantain

gulkämpar

strandkjempe

strand-vejbred

meriratamo

kattartunga *

M

H

L,R

8, 36

Valerianaceae

Valeriana officinalis

valerian

vänderot *

lege-vendelrot

lægebaldrian*

rohtovirmajuuri

gar∂abrú∂a

M,H

H

W,R

4, 9, 44, 49

Asteraceae

Achillea millefolium

yarrow

rölleka *

ryllik *

røllike *

siankärsämö

vallhumall

M

H

W,L,F

9, 34, 35, 38

Artemisia abrothanum

southernwood

åbrodd *

abrodd

ambra

aaprottimaruna

M

N

W

44

A. absinthium

wormwood

malört *

ekte malurt *

malurt *

mali *

M,C,S,H

H,C

W,L,S

5, 9, 25, 34, 44, 45, 49, 53, 55, 58

A. vulgaris

mugwort

gråbo *

burot

gråbynke *

pujo

M

H

W

9, 38, 49, 58

Cnicus benedictus

blessed thistle

kardbenedikt *

kardobenedikt*

korbendikt *

karvasohdake

M

H

W,L

9, 35, 44, 55

Helianthus annus

sunflower

solros

solsikke

solsikke

auringonkukka *

sólfifill

M

C

S

45

Inula helenium

elecampane

ålandsrot

alantrot *

lægealant *

isohirvenjuuri

hálsurt

M

H

R

9, 55

Matricaria maritima

sea mayweed

kustbaldersbrå

strand-balderbrå

kamille *

merisaunio

baldursbrá *

M

H

L,F

8, 9, 33, 36, 37, 41

Senecio vulgaris

Common groundsel

korsört *

åkersvineblom

Almindelig brandbæger*

peltovillakko *

krossfífill

M,C

C

L

9, 22, 45

Silybum marianum

milk thistle

mariatistel

mariatistel

marietidsel *

maarianohdake *

maríupistill

H

S

9, 53

Tanacetum balsamita

alecost

balsamblad

balsam *

okseøje

palsamipäivän-kakkara

M

H

W

35

T. parthenium

feverfew

mattram *

matrem

matrem

reunuspäivinkakkara

M

H

S

44

T. vulgare

common tansy

renfana *

reinfann *

rejnfan *

pietaryrtti *

regnfang

M,A,S,H

H,N,C,T

W,L,F,S

1, 4, 9, 10, 19, 30, 34, 35, 44, 45, 49, 53, 55, 58, 70

Liliaceae

Allium cepa

onion

rödlök *

rødløk *

rödløg *

punasipuli

rau∂laukur

M

H

W

9, 35, 44, 55

A. porrum

leek

purjolök

purreløk *

purløg

purjo

bla∂laukur

M

H

W

34

A. sativum

garlic

vitlök *

hvitløk *

hvidløg *

valkosipuli *

hvítlaukur

M,A

W,N,C

W

4, 9, 35, 44, 45, 55, 70

A. ursinum

ramson

ramslök

ramsløk *

rams-løg

karhunlaukka

bjarnarlaukur

M

H

W

34

Asparagus officinalis

asparagus

sparris

asparges

asparges *

ruokaparsa

M

9

Iris pseudocorus

iris

svärdslilja *

sverdlilje

gul sværdlilje*

keltakurjenmiekka

gula sver∂lilja

C,P

H

R

9, 30

Araceae

Acorus calamus

sweetflag

kalmus

kalmusrot

kalmus

kalmojuuri *

kalmusrót

M

C

R

45

Grasses

Poaceae

Elytrigia repens

couch grass

kvickrot *

kveke

Almindelig kvikgræs *

juolavehnä

húsapuntur

M

H

W,R

9, 18

Hordeum vulgare

barley

korn

bygg

byg *

ohra

bygg

M

9

Secale cereale

rye

råg

rug

rug *

ruis

rúgur

M

9

Host (if specified): M = human, A = animal, C = cattle, S = sheep, H = horse, P = pig.

Target (if specified): H = helminths, N = nematodes, C = cestodes, T = trematodes, P = protozoa.

Part used (if specified): W = whole plant, L = leaves, F = flowers, S = seeds, B = berries, H = shoots or buds, R = root or tuber, J = sap, P = phloem or bark, O = wood, C = charcoal or ashes, T = tar.

* Indicates that the plant is mentioned in literature from that Nordic country.

Note: Plants included in this table are based on generally historical reports. This does not imply endorsement by the authors in either their effectiveness against parasites, or safety for human and/or animal use.

Lichens and Ferns

One of the plants most commonly mentioned in the Nordic literature is male fern (Dryopteris filix-mas), a common fern that is widespread throughout the Northern hemisphere. Extracts from powdered rhizomes were first used by the Greeks (circa 350–250 BC) to treat tapeworm infections. This product (oil of aspidium) became an established product in many Pharmacopoeia of the Western World and was sold until the end of the 1940s. A number of active compounds have been isolated from this product, but it appears that the anthelmintic constituent is filicic acid.

Trees and Shrubs

Reports are few on the extensive use of trees and shrubs specifically to feed to livestock as treatment against parasites. However, products of willow (Salix spp). have been widely used as analgesics or antipyretics in humans, probably attributable to the content of salicin and derivatives. Salix spp. also has a reputation as an anthelmintic for humans and livestock. Horses fed leaves are not supposed to get worms and a decoction of the bark is efficacious against flukes (trematode parasites) and diarrhoea in sheep 9.

Herbaceous Plants

There is a great variety of these plant types that has been used as de-worming preparations. Whilst most of those mentioned in Table 1 thrive in the Nordic environment, many originated from other countries. Possibly one of the most widespread and commonly used herbal anthelmintic is oil of chenopodium, derived from Chenopodium ambroisoides, popularly known as American worm-seed, or goosefoot. Archeological and ethnological studies suggest that this material has been used for many centuries. It is of passing interest that in the early eighteenth century, Peter Kalm (1715–1779), a Swedish botanist and traveller, reported that it was used by both the indigenous inhabitants and European settlers in the American colonies for the treatment of Ascaris infections. Plants were taken to Europe, cultivated widely, and were soon in common usage. The active principle, ascaridol, a volatile terpene, was isolated and eventually synthesized. However, in the Nordic countries, Chen-opodium is not one of the most commonly mentioned plant families.

Some of the plants mentioned are now commonly used as spices eg. caraway (Carum carvi), thyme (Thymus spp) and mint (Mentha spp). These have been found in Russian studies to have effect against Trichostrongylus larvae in vitro and also in sheep 2415.

Members of the family Asteraceae have also a prominent position in the herbal de-worming literature. The Romans used dried, unexpanded flower heads obtained from several species of the genus Artemisia in the first century, for the treatment of Ascaris, Enterobius and tapeworm infections. The name given for this herbal preparation was semen-contra vermes (semen against worms), apparently because of its superficial resemblance to semen. It became an important member of the European pharmacopoeia until the early 20th century. The active principle was found to be the sesquiterpene lactone, santonin. More recent pharmacological studies have demonstrated the pharmacological basis of this chemical. Low concentrations of santonin are reported to have a selective toxic action on the ganglion located in the nerve ring of Ascaris spp. 60. Against other nematodes, such as Oxyuris spp and the cestodes, santonin is not effective 61. Pharmacological studies investigating the specific effects of santonin-containing herbal preparations are not known. This is probably because santonin had been isolated and used as a vermifuge as early as 1830. Due to its narrow therapeutic window (safety index) and toxicity, the crude drug santonin is no longer used 566613.

Another member of the Asteraceae family, more widely used in the Nordic countries, is common tansy (Tanacetum vulgare). The active component is claimed to be thujon. In vitro studies have shown an effect of this plant on Trichostrongylus and Ostertagia circumcincta spp. 2415. Vegetables, such as carrot (Daucus carota), brassicas (Brassica spp), the onion group (Allium spp.), as well as all kinds of berries have had widespread use against parasites in the Nordic as well as most other countries. Seeds of pumpkin and cucumber (Cucurbitaceae) have been used in tropical America for centuries as a treatment of tapeworm infections. From there the popularity of this remedy spread to Europe. The active component, cucurbitine, was identified as an amino acid (3-amino 3 carboxy pyrorolidin). Leaves from another tropical plant, tobacco (Nicotiana rustica), have enjoyed universal popularity and latterly notoriety for use in smoking. However, infusions of this plant, or synthetic analogues (e.g. nicotine sulphate) were commonly used as anti-nematode preparations in ruminant livestock up until the advent of the modern broad spectrum anthelmintics in the mid 1950s. Both these plants have also been grown and used as anthelmintics in the Nordic countries.

Pasture plants

The possible use of specialised crops to control nematode infections in grazing ruminants has attracted considerable research interest in recent years. Bioactive plants or forages with secondary metabolites, particularly legumes with a high content of pro-anthocyanidins (condensed tannins) e.g. sulla (Hedysarum coronarium) or lotus major (Lotus pedunculatus) have been reported to reduce worm burdens in grazing lambs by up to 50% 47. An in vivo anthelmintic effect has also been observed using quebracho, a condensed tannins extract, as a single high dose against sheep nematodes 3 and the capacity of purified condensed tannins from Danish legumes to kill nematode larvae in vitro has been demonstrated 39. However, in several field studies it has been difficult to relate anti-parasitic effects to the actual amounts of condensed tannins (e.g. 46). A complicating factor is that condensed tannins are a poorly defined group of compounds (basically polymers capable of covalently binding protein) making standardised determinations in plant material difficult.

It has been postulated that the beneficial effects of tanniferous plants against internal parasites could be due to one, or a combination, of the following factors:

• Tanniferous plants increase the supply and absorption of digestible protein by animals. This is achieved by tannins forming non-biodegradable complexes with protein in the rumen, which dissociate at low pH in the abomasum to release more protein for metabolism in the small intestine of ruminants – in other words, "natures protected protein." This indirectly improves host resistance and resilience to nematode parasite infections.

• Tannins have a direct anthelmintic effect on resident worm populations in animals.

• Tannins and/or metabolites in dung have a direct effect on the viability of the free-living stages (development of eggs to infective larval stages).

Although there is some evidence to support each of these above claims (for review, see 40), we believe that the data are by no means clear-cut 6.

Limitations with using plants as natural anthelmintics

It is not a simple matter of just growing these plants and expecting them to be used in a natural parasite control system. In a longer perspective, many issues need to be considered. These include, whether the chosen plants are amenable to cultivation and if so by what means (pure stands or as mixed leys), ease of harvesting seeds and thus their commercial availability, and means of use or administration (grazing, or individual stable feeding – short, or long term). In addition, factors such as palatability, stability, biodegradability of active compounds in preserved products, whether these are to be used curatively, or preventively, need to be considered. Finally, dosage may be difficult to control and the possibility of toxic side effects in animals needs to be considered.

Some of the potential candidate plants cannot withstand trampling by livestock, are poor competitors with other pasture species in mixed grazing swards (e.g. Lotus spp., 7), or they are preferentially sought out by grazing animals and thus easily succumb to even light grazing pressure (e.g. H. coronarium, 47).

Plants which have a high content of known direct-acting parasiticides (e.g. santonin in worm-seed) may be effective for short-term "curative" use eg. a short grazing interval on a "deworming" paddock before a pasture change. In other cases, plants may have to constitute a substantial proportion of the feed and may therefore be used in a preventive fashion mixed with grass and clover in larger grazing areas, or in pure stands for rotational grazing.

A word of warning – plant toxicity

The whole animal kingdom is dependent on the use of plant material. Plants have probably covered much of our planet throughout the history of multicellular life. This implies that herbivores have been too few in number to consume all the food available 28, and probably more importantly, that some plants have evolved defence mechanisms against being eaten by herbivorous animals 43. One of their defence principles is the production of chemical compounds, which may be harmful or distasteful to potential herbivores. The fact that certain plants could have adverse effects on man and livestock has been known since ancient times. Likewise, it has been recognised that some plants could be of benefit in disease conditions. These two aspects of the plant kingdom, the beneficial and the harmful properties of plants, strongly related to dosage, are described in the early medical literature of classical Greece and Rome (Hippocrates, Theophrastus, Dioscorides).

Modern scientific literature on plant effects on livestock deals mainly with adverse effects, and less attention has been paid to the curative potential of plant material. The complex nature of this discipline is reflected in the difficulties in classification of poisonous plants. Attempts to classify them according to the chemical nature of their active constituents are met with the obstacles that these may be either a single substance or a number of substances with wide differences in chemical properties. Accordingly, a chemical classification will lead to considerable overlapping with some plants featuring in several chemical groups. Albeit these difficulties, the majority of recent textbooks group the poisonous plants according to their known toxic constituents 11. These include a vast range of compounds that may be classified as alkaloids, glycosides, nitrates, oxalates, photodynamic substances, thiaminases, local irritants and phytooestrogens. The most reputed plants in the Nordic flora with reported responsibility for livestock poisoning include wolf's-bane (Aconitum lycoctonum) (alkaloids), cowbane (Cicuta virosa) (alkaloids), groundsel (Senecio spp.) (alkaloids), yew (Taxus baccata) (alkaloids), brassicas (Brassica spp.) (S-methyl cystein sulphoxide, pro-goitrin, nitrates, amongst others), foxglove (Digitalis purpurea) (digitalis-glycosides), bog asphodel (Narthecium ossifragum) (saponin-glycosides), sorrel (Rumex spp.) (oxalates), St. John's-wort (Hypericum spp.) (photodynamic substances), bracken (Pteridium aquilinum) (thiaminases, alkaloids), horsetail (Equisetum spp.) (thiaminases) and Ranunculus spp. (local irritants) 634248596771722571617. Several of these plants appear in Table 1 and thus are examples of both beneficial (according to popular belief!) and harmful properties of plants. One should be aware that there is some structural overlap between these simple chemical groups and that other classifications are possible. Furthermore, it must be borne in mind that little is known of the toxic constituents of many plants and that the poisonous properties of a plant may be due to more than one substance.

It is also important to understand that natural, often genetically determined, variations exist between different populations of some plant species, which may affect their toxic potential. An example of this is birdsfoot trefoil (Lotus corniculatus), in relation to cyanogenic glycosides. In different populations (cultivars), these substances may be absent, or the enzymes that break them down to release hydrocyanic acid may be absent, or both of them may be present. Consequently, if one of these constituents is lacking, the plant is harmless, and only when both are present the plant is poisonous. This knowledge is essential to make a rational selection of non-toxic cultivars of L. corniculatus as an important constituent for pasture leys.

Like any 'new' area of treatment against target pest organisms, the use of plant materials to control internal parasites should be tempered with common sense and based on scientific validation of a useful measure of efficacy, which at the same time is host benign.

Conclusion

This review provides ample evidence that a considerable amount of information relating to the use of plant material as de-worming preparations for man and his livestock in the Nordic countries, is available. However, almost all of these reports are historical and/or anecdotal. Evidence for effectiveness of plant de-worming preparations has been rarely obtained and little has been made available in scientific publications. With respect to increasing interest in the therapeutic use of natural products, we believe that it is important that a systematic evaluation is made of the botanical resources of the Nordic countries in relation to the purported de-worming properties of those plants that are endemic, or thrive, in this region of the world.

 Ahonen U Fytoterapian käsikirja (Manual for Phytotherapy) Gummerus kirjapaino Oy, Saarijärvi 1997 <p>Förgiftningspanoramat hos djur ((Poisoning panorama in animals)</p> Andersson G Hedhammar Å Holmgren A Persson H Tjälve H Förgiftningar hos djur. (Poisoning in animals). Svensk Veterinärtidning 1989 41 Supplement 19 5 37 <p>Evidence for direct anthelmintic effect of condensed tannins</p> Athanasiadou S Kyriazakis I Coop RL Jackson F WAAVP Conf Copenhagen 1999 f5.04 <p>Vallört och vitlök (Comfrey and garlic)</p> Bergmark M Prisma, Stockholm 1967 <p>Lust och lidande (Lust and suffering)</p> Bergmark M Natur & Kultur, Stockholm 1968 <p>The effect of birdsfoot trefoil (<it>Lotus corniculatus</it>) and white clover (<it>Trifolium repens</it>) in mixed pasture swards on incoming and established worm infections in young lambs</p> Bernes G Waller PJ Christensson D Acta Vet Scand 2000 41 351 361 11234969 <p>Birdsfoot trefoil</p> Beuselinck PR Grant WF Forages, An Introduction to Grassland Agriculture Iowa State University Press, Ames, Iowa, USA Barnes RF, Miller DA, Nelson CJ 5 1995 1 237 248 <p>Um íslenskar drykkurtir, söfnun þeirra, geymslu, nytsemi, verkanir og tilrei∂slu (About Icelandic plants used in drinks, their collection, storage, usefulness, effects and preparation)</p> Bjarnason A Prentsmi∂ja Nor∂ur- og Austuramtsins hjá H. Helgasyni 1860 <p>Folk og Flora – Dansk etnobotanik, vol. 1–4 (People and flora – Danish ethnobotany, vol. 1–4)</p> Brøndegaard VJ Rosenkilde og Bagger 1980 <p>Suomen myrkylliset ja lääke-kasvit, niiden vaikuttavat aineet, vaikutukset elimistöön, lääkkeinä käyttö sekä rohdoksis keräily ja viljely (Toxic and medicinal plants in Finland Effective ingredients, function and use in medicine. Cultivation and collection)</p> Cantell S Saarnio V Karisto Oy, Hämeenlinna 1936 <p>Poisonous plants and fungi in Britain</p> Cooper MR Johnson AW The Stationary Office, London 2 1998 <p>Usage of herbal medicine against helminths in livestock. An old tradition gets its renaissance</p> Danøe R Bøgh HB World Animal Review 1999 93 60 67 <p>Adverse Effects of Herbal Drugs</p> De Smet PAGM (Ed) Springer-Verlag, Berlin Heidelberg New York 1997 3 <p>Um sau∂féna∂ (About sheep)</p> Einarsson G Prentsmi∂ja Ísafoldar, Reykjavík 1879 <p>Effect of certain pasture plants on gastrointestinal nematodes of sheep</p> Eminov RS Sov Agric Sci 1982 1 72 74 <p>Nephrotoxicity of Narthecium ossifragum in cattle in Norway</p> Flåøyen A Binde M Bratberg B Djønne B Fjølstad M Grønstøl H Hassan H Mantle PG Landsverk T Schönheit J Tønnessen MH Vet Rec 1995 137 259 263 7502463 <p>Photosensitization disorders</p> Flåøyen A Frøslie A Handbook of plant and fungal toxicants CRC Press, Boca Raton D'Mello JPF 1997 191 204 <p>Nyttiga ogräs, del 2 (Useful weeds, part 2)</p> Fogelfors H Lantmannen 1984 3 19 <p>Nyttiga ogräs, del 7 (Useful weeds, part 7)</p> Fogelfors H Lantmannen 1984 8 51 <p>Nyttiga ogräs, del 10 (Useful weeds, part 10)</p> Fogelfors H Lantmannen 1984 11 31 <p>Nyttiga ogräs, del 16 (Useful weeds, part 16)</p> Fogelfors H Lantmannen 1984 18 38 <p>Nyttiga ogräs, del 17 (Useful weeds, part 17)</p> Fogelfors H Lantmannen 1984 21 44 <p>Nyttiga ogräs, del 22 (Useful weeds, part 22)</p> Fogelfors H Lantmannen 1985 3 52 <p>Action of medicinal plants on gastrointestinal nematodes of sheep</p> Gadzhiev YG Eminov RS Byulleten Vsesoyuznogo Instituta Gelmintologii im. K.I. Skryabina 1986 44 12 16 <p>Eläinden Tauti-kirja, kolmas ylöspano (Disease of Animals)</p> Ganander C J. D. Frendell ja poika, Helsinki & Turku 3 1829 <p>Factors influencing the application of anthelmintics in practice</p> Gibson TE Vet Parasitol 1980 6 241 245 10.1016/0304-4017(80)90045-X <p>The discovery and development of anthelmintics</p> Grove DI A History of Human Helminthology C.A.B. International, Oxford Grove DI 1990 75 101 <p>Community structure, population control, and competition</p> Hairston NG Smith FE Slobodkin LB American Naturalist 1960 94 421 425 10.1086/282146 <p>Kansanomainen lääkintätietous (Medicine in Folklore)</p> Hako M Suomalaisen Kirjallisuuden Seuran Toimituksia, KJ Gummerus OY, Jyväskylä 2 1982 229 4 <p>Välsignade växter (Blessed plants)</p> Hewe N Stockholm 1939 <p>Luonnonlääkkeet (Natural Medicine). Helsingin yliopisto oppimateriaaleja 27</p> Hiltunen R Holm Y Painotalo Miktor, Helsinki 1994 <p>Lækninga-Bók um þá helztu kvilla á kvikféna∂i, samantekin fyrir Islendinga og løgu∂eptir þørfum þeirra, af Jóni Hjaltalín, Studios. Chirurg. et Medic. (Medical book about the main ailments of livestock, compiled for the Icelanders and adapted to their needs, by Jóni Hjaltalín, Studios. Chirurg. et Medic.)</p> Hjaltalín J Kaupmannahöfn 1837 <p>Íslensk grasafræ∂i (Icelandic botany)</p> Hjaltalín J Oddur J Gefin út a∂ tilhlutun Hins íslenska bókmenntafélags, Kaupmannahöfn 1830 <p>Planter og tradisjon (Plants and tradition)</p> Høeg OA Universitetsforlaget, Oslo-Bergen-Tromsø 1976 <p>Våre medisinske planter (Our medical plants)</p> Høeg OA Forlaget Det Beste 1984 <p>Íslenskar lækninga- og drykkjarjurtir (Icelandic medical plants and plants used as drinks). 13</p> Jónsson BL Rit Náttúrulækningafélags Íslands, Reykjavík 1977 <p>Lítil ritgjör∂ um nytsemi nokkurra íslenskra jurta eptir ymsa höfunda (A booklet about the usefulness of some Icelandic plants by various authors)</p> Jónsson J Einar þór∂arson, Reykjavík 1880 <p>Junebys medicinalväxter (Juneby's medical plants)</p> Juneby HB Reformförlaget, Malmö 1984 <p>Anthelmintic effects of proanthocyanidins and related polyphenolics</p> Kahiya CJ Mukaratirwa S Thamsborg SM Ndlovo LR Proc WAAVP Conf Copenhagen 1999 g 6.86 <p>Tannins with anthelmintic properties. International Workshop on Tannins in Livestock and Human Nutrition</p> Kahn LP Diaz-Hernandez A Waite Campus, University of Adelaide. ACIAR Proceedings No 92 1999 130 139 <p>Rit Björns Halldórssonar í Sau∂lauksdal (The writings of Björn Halldórsson of Sau∂lauksdalur)</p> Kristjánsson G Sigfússon B (Ed) Búna∂arfélag Íslands, Reykjavík 1983 <p>Bog asphodel (Narthecium ossifragum) as a cause of photosensitation in lambs in Norway</p> Laksesvala B Dishington IW Vet Rec 1983 112 375 378 6857980 <p>Community structure, population control, and competition: A critique</p> Murdoch WW American Naturalist 1966 100 219 226 10.1086/282415 <p>En myckit nyttigh örta-book (A very useful book of herbs). 1642</p> Månsson A Rediviva, Stockholm 1987 <p>Vaivasta taudiksi. Lapamatoon liittyvä kansanparannus erityisesti pohjois-karjalaisen aineiston valossa (Dissertation: From Illness to Disease. Ethnomedicine associated with broad tapeworm with particular reference to material from Northern Karelia, Finland). Suomalaisen Kirjallisuuden Seuran Toimituksia 666</p> Naakka-Korhonen M Kirjakas/Kirjapaino Raamattutalo, Pieksämäki 1997 <p>Establishment and fecundity of <it>Ostertagia circumcincta </it>and <it>Trichostrongylus colubriformis </it>in lambs fed lotus (<it>Lotus pedunculatus</it>) or perennial ryegrass (<it>Lolium perenne</it>)</p> Niezen JH Waghorn GC Charleston WAG Vet Parasitol 1998 78 13 21 10.1016/S0304-4017(98)00121-6 9703616 <p>Growth and gastrointestinal nematode parasitism in lambs grazing either lucerne (<it>Medicago sativa</it>) or sulla (<it>Hedysarum coronarium</it>) which contains condensed tannins</p> Niezen JH Waghorn TS Charleston WAG Waghorn GC J Agric Sci Camb 1995 125 281 289 <p>Planteforgiftninger hos drøvtyggere i Rogaland. Et tilbakeblikk. Giftige planter og planteforgiftninger hos dyr i Rogaland (Plant poisoning in ruminants in Rogaland. A retrospect. In: Poisonous plants and plant poisoning in animals in Rogaland)</p> Nærland G Rogaland Veterinærforenings seminar på Utstein Kloster 1984 6 9 <p>Linnés hälsoörter (The medical plants of Linné)</p> Ohlmarks Å Sjöstrands förlag, Stockholm 1985 <p>Fer∂abók Eggerts Ólafssonar og Bjarna Pálssonar. Um fer∂ir þeirra á Íslandi árin 1752–1757. I og II bindi (The travel book of Eggert Ólafsson and Bjarni Pálsson. About their travels in Iceland in 1752–1757. Vol. I and II)</p> Ólafsson E Bókaút-gáfan Örn og Örlygur h.f., Reykjavík 1981 <p>Johannesört (St John's wort)</p> Pettersson B Tunón H Svanberg I Fauna och Flora 1998 93 202 206 <p>Jóns Péturssonar Handlæknis Nor∂lendinga frá 1775 til 1801 Lækninga-Bók fyrir almúga (The medical book of Jón Pétursson for the public). Yfirlesin, aukin og endurbætt af Landphysikus Jóni borsteinssynii og Handlækni Sveini Pálssyni</p> Pétursson J Útgefin af þorsteinii Jónssyni Stud. Theol., Kaupmannahöfn 1834 <p>Luonnon lääkekasvit (Medicinal Herbs in Nature)</p> Piippo S Helsingin yliopiston kasvitieteen monisteita 144. Helsinki 1996 <p>Mihin kasvimme kelpaavat, ruokaa, ryytiä ja rohtoa luonnosta (The use of our plants: Food, Drugs and Herbs from Nature)</p> Rautavaara T Werner Söderström OY, Porvoo-Helsinki-Juva 3 1976 <p>Våre folkemedisinske lægeurter (Our medical herbs)</p> Reichborn-Kjennerud I Centraltrykkeriet, Kristiania 1922 <p>Martindale The Extra Pharmacopoeia</p> Reynolds JEF Prasad AB (Eds) The Pharmaceutical Press, London 28 1982 <p>Forgiftningar hjå norske husdyr i 1990 (Poisoning in Norweigan domestic animals in 1990)</p> Sivertsen T Øvernes G Karlsen B Søli N Norsk Veterinærtidsskrift 1992 104 173 182 <p>Brugen af urter i græsmarken til husdyr (Use of herbs in pasture)</p> Smidt D KVL, M.Sc. Thesis 1997 <p>Aktuelle planteforgiftninger hos storfe og hest. Giftige planter og planteforgiftninger hos dyr i Rogaland (Plant poisoning in cattle and horses. In: Poisonous plants and plant poisoning in animals in Rogaland)</p> Solberg I Rogaland Veterinærforenings seminar på Utstein Kloster 1984 16 20 <p>A manual of Pharmacology and its Application to Therapeutics and Toxicology</p> Sollmann T W.B Saunders Company, Philadelphia 8 1957 <p>Lehrbuch der Pharmacognosie (Textbook of pharmacognosy)</p> Steinegger E Hänsel R Springer Verlag, Berlin 3 1972 <p>Parasite control methods in organic and conventional dairy herds in Sweden</p> Svensson C Hessle A Höglund J J Livestock Prod 2000 66 57 69 10.1016/S0301-6226(00)00155-X <p>Planteforgiftninger hos sau med særlig henblikk på norske forhold (Plant poisoning in sheep with focus on the situation in Norway)</p> Søli NE Norsk Veterinærtidsskrift 1981 93 87 91 <p>The influence of stocking rate on gastrointestinal nematode infections of sheep over a two-year grazing period</p> Thamsborg SM Jørgensen RJ Waller PJ Nansen P Vet Parasitol 1996 67 207 224 10.1016/S0304-4017(96)01045-X 9017869 <p>Integrated and biological control of parasites in organic and conventional production systems</p> Thamsborg SM Roepstorff A Larsen M Vet Parasitol 1999 84 169 186 10.1016/S0304-4017(99)00035-7 10456414 <p>Pharmacognosy</p> Tyler VE Brady LR Robbers JE Lea and Fabiger, Philadelphia 9 1988 <p>Alveld og andre sjukdommer med symptomer på fotosensibilitet hos sau. Giftige planter og planteforgiftninger hos dyr i Rogaland ("Alveld" (hepatogenous photosensitization) and other diseases with symptoms of photosensibility in sheep. Poisonous plants and plant poisoning in animals in Rogaland)</p> Ulvund MJ Rogaland Veterinærforenings seminar på Utstein Kloster 1984 23 29 <p>Veterinær homøopati: baggrund, principper og anvendelse med speciel fokus på økologiske malkekvægsbesætninger – et litteraturre-view (Veterinary homeopathy: background, principles and use, with special focus on organic dairy herds – a literature review)</p> Vaarst M Report from Danish Institute of Animal Science No. 731 1996 <p>Organic dairy farming and nematode parasitism. Infection patterns among replacement heifers in dairy herds not preventively treated with anthelmintics</p> Vaarst M Ploeger H Thamsborg SM Sørensen JT Livestock farming systems Wageningen Press. EAAP Publication Dent, McGregor, Sibbald 1996 79 85 90 <p>Husdjurens sjukdomar (Diseases of domestic animals)</p> Vennerholm J Dahlström H Stålfors H Albert Bonniers förlag, Stockholm 1920 <p>Aktuelle planteforgiftninger hos sau i Rogaland. In: Giftige planter og planteforgiftninger hos dyr i Rogaland (Plant poisoning in sheep in Rogaland. In: Poisonous plants and plant poisoning in animals in Rogaland)</p> Waldeland H Rogaland Veterinærforenings seminar på Utstein Kloster 1984 30 37 <p>Forgiftning med planter som gir hemolytisk anemi og/eller methemoglobinemi. In: Giftige planter og planteforgiftninger hos dyr i Rogaland (Poisoning with plants leading to haemolytical anaemia and/or methemoglobinaemi. In: Poisonous plants and plant poisoning in animals in Rogaland)</p> Øverås J Rogaland Veterinærforenings seminar på Utstein Kloster 1984 13 16