Coccidiose hos kvæg: En oversigt over coccidiearter, patogenese, epidemiologi og forebyggelse specielt i økologiske besætninger

Coccidiose hos kalve forårsages af arter af de encellede parasitter, Eimeria, der findes vidt udbredt i alle verdensdele, og som giver anledning til diarré og utrivelighed hos især unge og modtagelige dyr. Hos kvæg findes 12 forskellige Eimeria arter, der adskiller sig fra hinanden med hensyn til morfologi, livscyklus og patogenitet. Infektion med Eimeria kan diagnosticeres ved forskellige la-boratoriemetoder, hvorved bl.a. antallet og arten af coccidier forsøges fastslået. Således skabes grundlag for bestemmelse af hvilke forebyggende tiltag, der eventuelt bør iværksættes. Ved under-søgelse af 258 kalve fra 25 danske økologiske malkekvægsbesætninger fandt vi Eimeria-arter i alle (100%) besætninger og i 88% af kalvene. De fleste kalve udskilte meget lavgradige mængder af coccidier i gødningen, medens nogle havde særdeles høje coccidieudskillelser. Coccidiose er en multifaktoriel sygdom, og sværhedsgraderne af sygdommen varierer derfor fra subkliniske tilfælde til nogle med løs, pastøs fæces af en enkelt dags varighed eller profus diarré med dysenteri, tenesmus og evt. mors. De kliniske symptomer tillægges traditionelt tilstedeværelsen af coccidiearterne Eimeria zuernii og E. bovis. Kalvens modtagelighed for coccidiose afhænger bl.a. af råmælksforsyning og immunitet, ernæringsstatus, stress, og evt. forekomst af andre sygdomme (f.eks. samtidige helminth- eller virusinfektioner). Endelig har også miljøet betydning for udvikling af coccidiose, herunder opstaldningstæthed, klima og hygiejne. Total udryddelse af coccidier er ikke muligt pga. parasittens ubikvitære forekomst og resistens i miljøet, men kalven kan styrkes ved sikring af tilstrækkelige råmælksmængder og ved opretholdelse af høj hygiejne i kælvningsboksen, samt efterfølgende opstaldningsforhold. Aktiv immunisering (vaccination) har endnu ikke vist sig effektiv i større målestok. Der foreligger ikke yderligere retningslinier for forebyggelse i perspektiv af de økologiske regler. Kalve, der har klinisk coccidiose, bør isoleres fra de øvrige kalve og gives væsketerapi for at opretholde væskebalancen. Den bedste behandling er imidlertid forebyggelse - med fokus på belægningsgrad og høj hygiejne inklusive rigeligt med tør strøelse

Sundhed og velfærd i kalveholdet

Gennem de seneste år har vi arbejdet med en forståelse af dyrevelfærd i økologiske besætninger, hvor begrebet “naturlighed” har fået stor betydning. I en malkekvægbesætning er det ikke muligt at tilbyde køerne 100% naturlige forhold, men man kan tilstræbe at dyrene får mulighed for at udføre deres naturlige adfærd, har en stor grad af valgfrihed, har frisk luft, dagslys og adgang til udearealer. Det stiller imidlertid større krav til de mennesker, som arbejder med dyrene, bl.a. i forhold til øget opsyn samt til bedre at kunne vurdere, hvordan dyrene har det. I projektet er der bl.a. blevet udviklet en model til vurdering af velfærd hos kalve. Den første version er blevet implementeret i rådgivning af økologiske besætninger. Den forventes endvidere afprøvet i Norge, Storbritannien og Holland

A late requirement for Wnt and FGF signaling during activin-induced formation of foregut endoderm from mouse embryonic stem cells

AbstractHere we examine how BMP, Wnt, and FGF signaling modulate activin-induced mesendodermal differentiation of mouse ES cells grown under defined conditions in adherent monoculture. We monitor ES cells containing reporter genes for markers of primitive streak (PS) and its progeny and extend previous findings on the ability of increasing concentrations of activin to progressively induce more ES cell progeny to anterior PS and endodermal fates. We find that the number of Sox17- and Gsc-expressing cells increases with increasing activin concentration while the highest number of T-expressing cells is found at the lowest activin concentration. The expression of Gsc and other anterior markers induced by activin is prevented by treatment with BMP4, which induces T expression and subsequent mesodermal development. We show that canonical Wnt signaling is required only during late stages of activin-induced development of Sox17-expressing endodermal cells. Furthermore, Dkk1 treatment is less effective in reducing development of Sox17+ endodermal cells in adherent culture than in aggregate culture and appears to inhibit nodal-mediated induction of Sox17+ cells more effectively than activin-mediated induction. Notably, activin induction of Gsc-GFP+ cells appears refractory to inhibition of canonical Wnt signaling but shows a dependence on early as well as late FGF signaling. Additionally, we find a late dependence on FGF signaling during induction of Sox17+ cells by activin while BMP4-induced T expression requires FGF signaling in adherent but not aggregate culture. Lastly, we demonstrate that activin-induced definitive endoderm derived from mouse ES cells can incorporate into the developing foregut endoderm in vivo and adopt a mostly anterior foregut character after further culture in vitro

Ultrastructure of Sheep Primordial Follicles Cultured in the Presence of Indol Acetic Acid, EGF, and FSH

The aim of this study was to investigate the ultrastructural characteristics of primordial follicles after culturing of sheep ovarian cortical slices in the presence of indol acetic acid (IAA), Epidermal Growth Factor (EGF), and FSH. To evaluate ultrastructure of primordial follicles cultured in MEM (control) or in MEM containing IAA, EGF, and FSH, fragments of cultured tissue were processes for transmission electron microscopy. Except in the control, primordial follicles cultured in supplemented media for 6 d were ultrastructurally normal. They had oocyte with intact nucleus and the cytoplasm contained heterogeneous-sized lipid droplets and numerous round or elongated mitochondria with intact parallel cristae were observed. Rough endoplasmic reticulum (RER) was rarely found. The granulosa cells cytoplasm contained a great number of mitochondria and abundant RER. In conclusion, the presence of IAA, EGF, and FSH helped to maintain ultrastructural integrity of sheep primordial follicles cultured in vitro

genetic structuring and differentiation of echinococcus multilocularis in slovakia assessed by sequencing and isoenzyme studies

AbstractNucleotide sequencing of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene and isoenzyme analysis were used to survey the genetic variability in Echinococcus multilocularis populations from Slovakia. A sample of 12 isolates acquired from 10 different districts from red foxes exhibited identical sequences. Compared with the previously described E. multilocularis variants, one base substitution was consistently observed relative to the M1 variant (detected in China, Alaska, North America, Japan) and three base substitutions were recorded relative to the M2 variant (detected in Germany) in the CO1 fragment. These data, along with the recently gathered data from French isolates, are indicative of a genetically unique population occurring in Central and Western Europe. Electrophoretic examination of enzymes produced by 14 gene loci revealed intraspecific polymorphism only with the glucose-phosphate isomerase (two distinct patterns) and the mannosephosphate isomerase (four genotypes composed of three alleles) enzyme systems. To allow a fast species differentiation of E. multilocularis and E. granulosus (specifically, the G7 genotype occurring in Slovakia), discriminative electrophoretic characters between the species were obtained by isoenzyme analysis. Fixed genetic differences between the species were detected in the glucose-phosphate isomerase, esterase and aldolase systems, and partial differences were detected in four additional systems

Advances in prevention and therapy of neonatal dairy calf diarrhoea : a systematical review with emphasis on colostrum management and fluid therapy

Neonatal calf diarrhoea remains the most common cause of morbidity and mortality in preweaned dairy calves worldwide. This complex disease can be triggered by both infectious and non-infectious causes. The four most important enteropathogens leading to neonatal dairy calf diarrhoea are Escherichia coli, rota-and coronavirus, and Cryptosporidium parvum. Besides treating diarrhoeic neonatal dairy calves, the veterinarian is the most obvious person to advise the dairy farmer on prevention and treatment of this disease. This review deals with prevention and treatment of neonatal dairy calf diarrhoea focusing on the importance of a good colostrum management and a correct fluid therapy