PERMANENT TRANSMISSION OF ENDOPARASITES IN LARGE HERDS OF CATILE

Bej§ovec, J.: Permanent Transmission of Endoparasites in Large Herds of Cattle. Acta vet. Bmo,60, 1991: 205-212. Calving houses were found to be cohtaminated with endoparasites by the first crop of pregnant cows arriving in the new premises. No significant differences were found in the incidence of endoparasite species between new and old calving houses by' artalysis of variance. The proportions of dams excreting coccidial oocysts and gastroenteronematode eggs were 97.2 % and 38.1 %,respectively. The calves became. infected with small numbers of endoparasites. After transfer to large-capacity calf houses coccidia and· gastroenteronematodes were found in 57.8 % and 7.1 % of them, respectively. The .intensity. of their infection was, for the most part,. weak. After being changed to plant nutrition all calves became infected with coccidia and. the intensity of their infection underwent a large temporary increase; some animaIsshowed clinical coccidiosis. From large-capacity calf houses a wide spectrum.of coccidial and geohelminth species was transmitted to further animal categories· including grazing cattle. The most frequently. transmitted parasites are highly pathogenic coccidia Eimma bwis and E. zuernii. The intensity of infection was, for the most part, weak. Cattle, large herds, animal category, coccidia, helminths,. transfer Bovine parasites in large. herds of cattle in the Czechoslovak Federati¥e Reput;lie hav.e keD: considerably affected by veterinary measures and modern animal husbandry and animal hygiene practices conducted there for several years. Helminthoses are now present mainly in the su~ nical form (Hovorka and. Corbal984). In his study on gastroenteroheIiDinthoses Chraust (1967) pointed out that" ••• besides clinically diseased animals it is mainly thepresenceofasymptomatic conditions which can worsen and accelerate processes of another aetiology, impair the immunity to infectious diseases and exert serious adverse effects on general perfOrmance of the animals". According to Supperer (1973), a.o.,helminth larvae parasitizing in the alimentary tract of calves may activate, in the process of their migration, latent viraI and bacterial infections of the respiratory tract. In recent years the interest in helminthoses in our country· receded· and it has become necessary to pay more attention to coccidiosis. The danger of coccidiosis was pointed out by Zaji(!ek (1962) as early as the first l8rge-capacity calf houses in our C'ountry were being designed. Put into operation, these large-capacity calf houses gave rise to conditions favourable to coccidia which infect calves very soon after birth (Bejlovtc 1985, 1986). Pavlasek (1985) found coccidia in barns housing dams. Coccidia cause mortality among calves and decrease their body mass, on average, by 12: to 20 kg (Chroust 1966). Aecording to Papa<!ek and Pavlasek (1984) the body mass of coccidia-infected calves was decreased by 10 to 50 %. Bedrnfk et aI. (1980) drew attention to the role of coccidia in the pathogenesis of diarrhoeal diseases among calves. Chroust (1964) examining dead calves found bronchopneumonia as a complication of coccidiosis. According to MenUlt et al. (1984), &.0., the morbidity and mortality of calves kept under intensive husbandry conditions are generally,the result of synergic action of many. microorganisms.

Bovine parasites in large.herds of cattle in the Czechoslovak Federati¥e Reput;lie hav.e keD: considerably affected by veterinary measures and modern animal husbandry and animal hygiene practices conducted there for several years.Helminthoses are now present mainly in the su~ nical form (Hovorka and. Corbal984).In his study on gastroenteroheIiDinthoses Chraust (1967) pointed out that" ••• besides clinically diseased animals it is mainly thepresenceofasymptomatic conditions which can worsen and accelerate processes of another aetiology, impair the immunity to infectious diseases and exert serious adverse effects on general perfOrmance of the animals".According to Supperer (1973), a.o.,helminth larvae parasitizing in the alimentary tract of calves may activate, in the process of their migration, latent viraI and bacterial infections of the respiratory tract.In recent years the interest in helminthoses in our country• receded• and it has become necessary to pay more attention to coccidiosis.
The danger of coccidiosis was pointed out by Zaji (!ek (1962) as early as the first l8rge-capacity calf houses in our C'ountry were being designed.Put into operation, these large-capacity calf houses gave rise to conditions favourable to coccidia which infect calves very soon after birth (Bejlovtc 1985(Bejlovtc , 1986)).Pavlasek (1985) found coccidia in barns housing dams.Coccidia cause mortality among calves and decrease their body mass, on average, by 12: to 20 kg (Chroust 1966).Aecording to Papa<!ek and Pavlasek (1984) the body mass of coccidia-infected calves was decreased by 10 to 50 %.Bedrnfk et aI. (1980) drew attention to the role of coccidia in the pathogenesis of diarrhoeal diseases among calves.Chroust (1964) examining dead calves found bronchopneumonia as a complication of coccidiosis.According to MenUlt et al. (1984), &.0., the morbidity and mortality of calves kept under intensive husbandry conditions are generally,the result of synergic action of many.microorganisms.
• .On small farms calv~s are mostly grown in the herds where they were born.Under intensive husbandry conditions animals are often transferred from one place to another.Cerny and Bukvaj (1983), in their study on energy metabolism of such animals, have found that the adaptation of animals to new conditions and regrouping constitute a heavy load.Transfer of animals also increases the possibility of transmission of various pathogens.In the present study we tried to assess the penetration of coccidia and helminths into different categories of cattle.
• Some parasite species may be transmitted to large herds of cattle from free-living ruminants.In consequence of collectivization in our country the roe deer Capreolus capreolus L. spread to farm ands.The "field ecotype" Capreolus capreolus then developed by adaptation to new biocoenoses.Our study was therefore extended to cover roe deer living on farm lands.

Materials and Methods
Coprological examination for pneumohelminthswas carried out with Baermann's method and that for flukes with Breza's flotation-sedimentation method.The infection with gastroenteronematodes and coccidia was assessed qualitatively according to Breza (1957) and quantitatively according to Breza and Svarc (1968).The methods are described in detail in a manual entitled Veterinarni laboratorni vysetiovaci metody (1975).Considerable time was devoted to each examinstion so that even weak infections, which may pass unnoticed, under routine diagnostic practices, could be demonstrated.The determination of helminth species was also based on necropsy findings.• . . . .A total of 14 069 animals were examined in large herds of cattle in Central Bohemia.The numbers of animals examined in 8 differt;nt categories are given in Results under points (1) to (8).The same figures are.used in histograms to designate the bars illustrating the parasitization of the 8 animal c!ltegories, from c~v.es in calving houses to grazing cattle, with the respective coccidial and helminth species.Moreover, 650 roe deer feeding mainly on fodder plants in an agricultural area near Skvorec, ilbout 20 km to the east of Prague, were examined with ,the !lame, methods as described above ..
. '. From the afore-mentioned findings it can be seen that the• highest proportion of coccidia-infected animals was found among dams.New calving houses become contaminated by the first crop of pregnant cows.Evaluation of the data by ana:Iysi-1 2 3 4 5 6 7 8 of variance revealed no significant differences in the incidence of individual endoparasite species between old and new calving houses.A significant difference (P < 0.05 and P < 0.10) was found only in sporadically occurring Eimeria wyDmingensis which were not detected in new calving houses.
The dams excreted 10 species of coccidia and 12 genera of gastroenterohelminths (histogram bars above figures 6).The endoparasite species detected in the dams agreed with those found in their calves (histogram bars above figures 1, 2, 3).Calves become infected mosdy by licking various surfaces and by sucking milk from their dams or nursing cows.In some cases infection is caused by inadequate cleansing of the mouth upon post-parturient treatment and by insufficient treatment of the calves, particularly on Sundays and when animal attendants are changed and at night parturitions.Where cows in some calving houses without bedding are considerably dirty, the hygiene of calving is a problem and the environment is contaminated.The most frequently infected calves were those housed together 20 Oesophagostomum spp.with.thedams.Calves housed individually in cages or in stanchion pens were in-,fected sporadically.Calves arriving to large-capacity calf houses from extensive catchment-areas bring along a wide spectrum of endoparasite species.Thus the proportion of infected animals increases, while the intensity of infection remains weak.After the change from milk nutrition to plant nutrition the proportion of animals infected with coccidia increases to 100 %, the intensity of the infection shows a high temporary increase and clinical coccidiosis is often observed.From large-capacity calf houses endoparasites and particularly coccidia are transmitted, step by step, to all the remaining animal categories.
Coccidia were found to occur not only in barn environments but also in grazing cattle where they were detected in Our study conducted on cattle ranging from newborn calves to the oldest age categories provided evidence of the continuity of transmission of endoparasites and their permanent circulation in, cattle kept wider intensive husbandry conditions.
Comparison of the findings of co<rcidia and, helminths between the 8 categories was made by analysis of variance.Using Scheffe's method significant (p.< 0.01) differences were found only in the infection with helminths between animals housed in buildings and those on pasture.' .,Grazing cattle may also become Infected with some helminth parasites of free--living ruminants.Out of 650 roe deer (Capreolus capreolus L.) examined the following proportions of the animals were, infected with helminths that paratisize also in cattle: 46.8 % with Chabertia avina, 14.2 % with Trichuris avis, 6.8 % with Haemonchus contortus, 5.4 % with 1)ictyocaulus viviparus and 0.5 % with Moniezia b~nedeni.The intensity of their infection was generally weak.
In,large,herds of cattle kept under intensive husbandry conditions we have to take into account permanent transmission of endoparasites, particularly highly pathogenic Eimeria bavis and E. zuernii.They manifest themselves in animals weakened by various influences.After weaning, in particular, clinical coccidiosis can be expected .

Discussion
\ , Our ~aminations 'of cattle for <roccidia and geohelminths were carried out in large bovine herds.The only finding of a biohelminth dependent upon intermediate host (tapeworm Moniezia spp.) was made in one cow out of 14069 animals examined.Ftom our results it appears that barn environments favour the development of coccidia and geohelminths also in winter.The temperature at central--heating r~diators is favourable ,to the sporulation of coccidial oocysts and to the development of helmintlt •larvae~ The high stocking density in large herds is accentuated by the animals themselves.Calves penned in groups rest closely to one another (Kovalcik et al. 1977).Trichos~l'ongylus spp~ "The tendency of cows :to cluster on pasture was described by Stricklin(1983), !<;otv,asand Vrava:k (1984) a.o. V HiS andNavratil (1982) have reported that calves lick one, another from the first post-"natalday,:~cularlyifthey are penned together after birth.Diarrhoeic calves, in particular, lick various, surfaces most in-.tensely.From tOur observations it appears that animal behaviour plays a major , role in, the transmission of endoparasites ,tions (Bejsovec 1986) .
. .Under' intensive husbandry practices it is very difficult to remove coccidial oQCysts and.helminth, eggs ' .from barn surfaces and from animals which are often shifted from one place to another.Endogenous stages of endoparasites in the prepatent period cannot be detected by even very careful coprological examination.
It has, often been claimed that parasites are transmitted to cattle from game, particularly from roe deer.In our study the ~ung nematode Dictyocaulusvivipa-rUs was found in' 504 % of the roe deer examined but in no" inStance in cattle.

Fig. 6 .
Fig. 6.FOl" legend see 'Fig.1.' ) grazing cattle.The figures correspond to those of the 8 paragraphs at the beginning of Results where the numbers of animals examined and the proportions of those infected with coccidia and helminths are specified.