Rise In Faecal Egg Counts Research Articles

Peri-parturient rise in faecal strongyle egg counts of different genotypes of sheep in North Sumatra, Indonesia

Faecal strongyle egg counts were monitored in peri-parturient ewes and dry ewes grazing in a rubber plantation in North Sumatra, Indonesia. A significant rise in faecal egg counts was observed during the post-parturient period. Haemonchus contortus was the dominant species in the faecal cultures of the lactating ewes. The intensity of the peri-parturient rise was affected by the genotype of the sheep, which were the local Sumatra and its F1 crosses with St. Croix, Barbados Blackbelly and Java Fat-tail. The peri-parturient rise in egg counts was highest in Sumatra and lowest in the Barbados Blackbelly X Sumatra cross. A significant effect of litter size on the peri-parturient rise was also demonstrated. These findings are discussed in relation to the epidemiology and control of gastrointestinal nematodes in the humid tropics.

Strongyle infections in sheep and goats under the traditional husbandry system in peninsular Malaysia

Faecal egg counts were used to study patterns of trichostrongyle infections in sheep and goats according to season, age, pregnancy and lactation on traditional farms in west Malaysia. Haemonchus contortus and Trichostrongylus spp. were the most important strongyles in sheep and in goats, H. contortus, Trichostrongylus spp. and Oesophagostomum spp. were most prevalent. The faecal egg counts of sheep and goats were apparently not influenced by the small seasonal climatic variations. Strongyle infections were acquired at an earlier age in sheep than in goats. Mean faecal egg counts decreased from the age of 8 months onwards in sheep while in goats this occurred from 12–18 months onwards. A periparturient rise in strongyle egg counts was observed in both animal species. Haemonchus contortus was mainly responsible for this rise in faecal egg counts. The results are discussed with reference to control of gastrointestinal strongyle infections in sheep and goats.

Pathophysiology of the periparturient egg rise in sheep: a possible role for IgA

The relationship between anti-parasite IgA antibody levels in plasma and the periparturient egg rise in sheep was investigated. Ostertagia circumcincta larvae (5000 third stage larvae three times weekly) were administered to three groups of seven adult immune ewes from 12 weeks before until three weeks after lambing (group 1) or from six (group 2) or 14 (group 3) weeks before until three weeks before lambing. Seven additional ewes were not challenged (group 4 controls). Ewes in groups 1, 2 and 4 received anthelmintics 14 weeks before lambing. Challenge of the pregnant ewes with O circumcincta larvae resulted in substantial increases in faecal egg counts only during the periparturient period regardless of the larval dosing regimen. Furthermore, the periparturient rise in faecal egg counts was closely associated with a significant increase in anti-parasite IgA antibody levels in plasma. This rise in IgA antibody levels occurred at a time when IgA is transported from the gut to milk during early lactation. It is postulated that this may lead to a temporary reduction in abomasal antibody levels of ewes and hence permit the establishment of larvae and, or, the emergence and development of inhibited larvae and thereby lead to the periparturient rise in faecal egg count.

Effect of grazing management on minimising effects of parasitic nematodes on lamb production

An integrated management system involving cattle, ewes and lambs developed to minimise levels of parasitic nematode contamination of pasture was evaluated in a 2-year (1989-1991) study. Four experimental farmlets were managed as self-containcd units over a May-May year. Over the two years, stocking rate averaged 15 su/ha and cattle:sheep ratio 35:65. Three treatments (lambs regularly drenched, ewes drenched post-lambing/ lambs undrenchedand undrenchedewes andlambs) were similarly managed (set-stocked, lambing to weaning, 7-day shifts post-weaning, a 77-day interval between consecutive lamb grazings and a strict rotation of lambs followed by ewes with cattle midway between the ewe and subsequent lamb grazing). A fourth treatment differed in each year: in year 1, lambs were set stocked over summer and in year 2 cattle followed lambs, and ewes were positioned mid-way in the rotation between lambs and cattle, In both years, the management system developed to minimise nematode parasitism in lambs mamtained low levels of infective larvae on pasture (~80 L3 larvae/kg pasture), and a faecal egg count in lambs of less than 1500 epg; clinical parasitism was not observed. However, regular anthelmintic drenching of lambs significantly (P~0.01) increased liveweight gain of lambs from weaning in November to May by an average 35% over the 2 years. In year two, grazing ewes ahead of lambs significantly increased (PcO.01) pasture larvae levels and lamb faecal egg counts and decreased liveweight gain compared with grazing cattle ahead. Drenching ewes to minimise effects of the post-parturient rise in faecal egg count had no influence on nematode levels in lambs or on lamb performance. Keywords parasitic nematodes, grazing management, lamb growth

Pathophysiology of the periparturient egg rise in sheep: the role of prolactin

The involvement of prolactin in the periparturient rise in the faecal nematode egg count in sheep was investigated. Ostertagia circumcincta larvae (5000 third stage larvae three times weekly) were administered to adult immune ewes from three weeks before parturition to three weeks afterwards. Ten ewes were injected twice daily with 2-bromo-alpha-ergocryptine (bromocriptine), an antagonist of prolactin secretion, for two weeks starting two days after lambing while 10 ewes remained untreated. Bromocriptine treatment was initiated approximately two weeks pre partum in three other ewes. Plasma pepsinogen concentrations rose significantly by one week after the start of O circumcincta larval challenge in all the ewes but faecal egg counts remained negative until approximately one week post partum. Plasma prolactin concentration was reduced to a very low level in all bromocriptine treated ewes but this did not alter the dynamics of the periparturient rise in faecal egg counts. Neither cell-mediated nor humoral immunity of the ewes, as assessed by their sensitivity to BCG inoculation and by antibody titre raised against horse red blood cells, respectively, were impaired during the rise in faecal egg count, nor were these parameters altered by manipulation of plasma prolactin concentration. Lamb growth rate was not retarded by low plasma prolactin concentration in the bromocriptine treated ewes. These results are not consistent with the generally held hypothesis that elevated plasma prolactin concentration is directly associated with the periparturient rise.

Autumn-born lambs — Responses to use of anthelmintics and selenium

Abstract Extract Madam:—Out of season (autumn/winter) lambing is expanding in northern areas. These lambs need to grow at moderate rates through the late winter feed trough so they can fully utilise the spring flush to reach heavy weights before summer. Autumn-born lambs are likely to face high parasite roundworm challenge pre- and post-weaning. Strongyle faecal egg counts of autumn and spring-born lambs at weaning averaged 2000 and 400 eggs/g respectively (n=30) under an all-sheep, splitseason lambing policy near Kaikohe. (7) McSporran, K.D. and Andrewes, W.G.K. 1987. Field study of the post-parturient rise in faecal egg counts of lactating ewes. The effects of season, genotype of ewe and number of lambs born per ewe. Inter. J. Parasit., (pers. comm) [Google Scholar] Roundworm infestation can also reduce selenium concentration in the liver. (2) Andrews, E.D., Hogan, K.G. and Brunsdon, R.V. 1971. Some effects of anthelmintic dosing on the mineral status of hoggets. Proc. N.Z. Soc. Anim. Prod., 31: 65–65. [Google Scholar] Although Se level in pasture tends to be higher in autumn/winter than in spring/summer (l) Andrews, E.D., Grant, A.B. and Stephenson, B.J. 1964. Weight responses of sheep to cobalt and selenium in relation to vitamin B12 and selenium concentrations in liver and kidney. N.Z. J. agric. Res., 13: 17–27. [Taylor & Francis Online] , [Google Scholar] this could be offset by lower pasture availability. Better winter growth rates have been recorded in weaned calves from a combination anthelmintic/selenium drench than from either of these alone. (5) McLeod, C.C., Wolff, J.E. and Schwarz, G. 1975. Effect of anthelmintic and selenium drenching on liveweight gain in young beef cattle. N.Z. J. exp. Agric., 4: 219–225. [Google Scholar]

Haemonchus contortus and other trichostrongylid infections in parturient, lactating and dry ewes

From autumn (April) to spring (November), groups of pregnant and dry Merino ewes grazed pasture contaminated with infective larvae of Haemonchus contortus, Ostertagia circumcincta and Trichostrongylus colubriformis. A periparturient rise in faecal egg counts occured in the pregnant ewes, following the maturation in early spring of arrested fourth-stage larvae of H. contortus and failure of pregnant ewes to expel the resulting adult worms. Peak egg counts were seen in September, just before lambinf. In dry ewes, egg counts were slightly elevated at the time of the rise in the pregnant ewes, but fell to very low levels as adult worms developing from previously arrested larvae were expelled. Lactating ewes acquired greater burdens of O. circumcincta and T. colubriformis than did dry ewes, but were equally refractory to new infections with H. contortus. It is therefore suggested that the impairement of immunity to helminth infection seen in reproductive ewes may be more specific than was previously envisaged.

The periparturient rise in fecal egg counts in three strains of Florida native ewes and its value in predicting resistance of lambs to Haemonchus contortus

The periparturient rise in fecal egg counts in three strains of Florida Native ewes and its value in predicting resistance of lambs to Haemonchus contortus. International Journal for Parasitology 16: 185–189. Significant ( P < 0.05) differences in the magnitude of the periparturient rise in fecal egg counts (PPR) occurred in ewes of three strains of Florida Native sheep. Non-lambing ewes ( n = 12) and lactating University strain ewes ( n = 31), a strain selected over a 26-year period for parasite resistance by survival at pasture without anthelmintic treatment, had lower fecal egg counts than ewes of either Maxcy strain ( n= 17), a commercial strain treated regularly with anthelmintics, or Backlinie strain ( n = 16), a strain of Florida Native sheep that had some crossbreeding to Hampshire and Suffolk in their genotype and were regularly treated with anthelmintics. Whereas both Maxcy and Backlinie ewes showed a pronounced PPR, none occurred in non-lambing ewes ( n=12) and the slight rise in fecal egg counts observed in University ewes was not significantly different from that of the non-lambing ewes. Backlinie ewes having twin lambs ( n = 5) had a higher PPR than Backlinie ewes with single lambs ( n = 11) or Maxcy ewes with single lambs ( n = 15), but all three groups had higher PPRs than University ewes with single lambs ( n = 27). No differences occurred in fecal egg counts of non-lambing ewes regardless of strain. Six weeks after weaning fecal egg counts of all ewes were uniformly low regardless of strain or prior lactation status. Ram lambs born to these ewes showed no significant strain differences in Haemonchus contortus burdens after experimental infection, deworming with levamisole and reinfection, although University lambs ( n= 13) had lowest mean worm burdens at necropsy (2437) followed by Maxcy lambs ( n= 12, mean =3106) and Backlinie lambs ( n= 13, mean =3670). There was no significant correlation between worm burdens in these lambs and the magnitude of the PPR in their dams. Eight to 16 weeks after turn out to a common parasite-infested pasture ewe lambs ( n = 13) born to University ewes had lower fecal egg counts than similar ewe lambs ( n=8) born to Backlinie ewes. Prior to this time differences were not significant and egg counts were generally low. The magnitude of the PPR in their dams was not significantly correlated with fecal egg counts or PCVs of individual ewe lambs.

Resistance of nonlambing exotic and domestic ewes to naturally acquired gastrointestinal nematodes

No breed differences in Haemonchus contortus burdens were found when nonlacfating exotic (St. Croix and Barbados Blackbelly), domestic (Finn-Dorset × Rambouillet) and 1 2 exotic- 1 2 domestic ewes grazed fall pasture, but all ewes had significantly ( p < 0.05) lower worm burdens at necropsy than tracer lambs grazing the same pasture. Florida Native ewes grazing the same pasture showed significantly ( p < 0.05) less packed cell volume (PCV) decrease and significantly ( p < 0.05) lower fecal egg counts than the other ewe breeds but were not available for necropsy. Tracer lambs had a significantly ( p < 0.05) greater PCV decrease and significantly ( p < 0.05) higher fecal egg counts than ewes. The results of this study suggest that breed differences in the periparturient rise in fecal egg counts of exotic and domestic ewes observed in an earlier study may have been caused by breed differences in the periparturient relaxation of immunity rather than breed differences in the ability to acquire immunity to worms.

A comparison of the periparturient rise in fecal egg counts of exotic and domestic ewes

Ewes of three exotic breeds (Florida Native, Barbados Blackbelly and St. Croix) showed no periparturient rise in fecal egg counts (PPR) when housed from late fall through lambing and weaning. Domestic breed ewes (Rambouillet and Finn-Dorset × Rambouillet) showed a pronounced PPR 6–7 weeks post-lambing while St. Croix × domestic ewes showed an intermediate PPR under similar conditions. There was no PPR in non-lambing ewes. In a second experiment, breed differences in the PPR were not as pronounced when ewes were allowed to graze a contaminated pasture after lambing. Florida Native, St. Croix and 3 4 St. Croix × 1 4 domestic showed lower PPRs than the remaining breeds (Barbados Blackbelly, F 1 hybrids of exotic and domestic breeds and domestic ewes), but the magnitude of the PPR was generally small in all breeds. No relationship was observed between hemoglobin genotype and PPR in either experiment. It was concluded that a low or absent PPR is an important manifestation of breed resistance in exotic ewes and that this may be useful as a marker for breeding parasite-resistant sheep.

Effects of parasite control in the peri-parturient period on lamb birth weight and liveweight gain

The effect of pre- and post-lambing anthelmintic treatment of the ewe on subsequent lamb production was studied. Sixteen groups of 25 maiden Border Leicester x Merino ewes were given combinations of a pre- and post-lambing 'drench' with thiabendazole. All groups were pastured on separate paddocks giving four replicates of each treatment program. Lamb liveweight changes were recorded for 19 weeks. A pre-lambing drench was found to increase lamb birth weights, and this advantage persisted until the lambs were drafted for slaughter in the nineteenth week from the beginning of lambing. The advantage was greater for twin compared with single lambs. The post-lambing drench had no effect on liveweight gain up to week 13, but had a significant effect over the next six weeks. This result seemed to have been related to the lower parasite burdens being passed from the ewe to the lamb, as a result of the post-lambing drench. This drench controlled the rapid rise in faecal egg counts which was observed in the lambs of untreated ewes after the eleventh week. At the time of lambing, pasture contamination was probably lower than under many practical field situations and results of the same magnitude may not occur regularly. The implications, however, are greatest in flocks with a high twinning performance where early drafting of a high percentage of twin lambs is important for economic or pasture management considerations.

Haemonchus contortus infection in ewes: Blastogenic responses of peripheral blood leukocytes to third stage larval antigen

Ewes were infected weekly with infective third-stage Haemonchus contortus larvae until parturition (1–16 doses of infective larvae). Peripheral blood leukocytes from these ewes were tested for in vitro blastogenic responses to phytohemagglutinin, to a non-helminth antigen the purified protein derivative of tuberculin (PPD), and to third-stage larval H. contortus antigen during pregnancy, parturition and lactation. Fecal egg counts were determined on a weekly basis for all ewes. Parturient lactating ewes showed a peri-parturient rise in fecal egg counts while barren ewes or parturient, nonlactating ewes did not. Blastogenic responses of a majority of parturient lactating ewes indicated an inverse relationship to fecal egg counts. In contrast, blastogenic responses of barren or nonlactating ewes did not demonstrate this inverse relationship. It is suggestive that hormonal factors or other serum factors affect antigen-induced blastogenesis during parturition and lactation in the sheep.

The Acquisition of Trichostrongylid Infection by Grazing Lambs

Summary A grazing experiment was carried out during 1966–1968 in an attempt to identify the source of the larvae which initiate infection in grazing lambs. The post-parturient rise in faecal egg count was abolished in the ewes but was replaced by eggs of T. colubriformis passed by artificaily infected 5-month-old Dorset Horn lambs. The acquisition of infection in 2 years appeared to result principally from the larvae derived from the simulated post-parturient rise but in the third year residual pasture infection was important. Paddocks continuously grazed by lambs over a number of years became dangerously infected with Nematodirus spp.

Pre-mating anthelmintic treatment of ewes and its effect on lambing performance.

Abstract Extract The study of helminth infections of breeding ewes has been concentrated particularly on the post-parturient rise in faecal egg counts (Connan, 1968). New Zealand studies on this phenomenon including economic returns from anthelmintic treatment of ewes prior to lambing and after lambing have been conducted by Brunsdon (1964, 1966a, b, c, 1967, 1970), Lewis and Stauber (1969) and Leaning et al. (1970).

The Absence of the Post-Parturient Rise in Faecal Egg Count and its Effect on the Control of Gastrointestinal Nematodes in Lambs

The treatment of ewes with thiabendazole before tupping resulted in their faecal egg counts being low the following spring. The ewes were grazed on land upon which the residual herbage larval count was very light and their lambs reached fat lamb weight without the acquisition of a significant worm burden. Le traitement de brébis au thiabendazole avant la monte entraîna une baisse de la numération d’oeufs fécaux le printemps suivant. Les brébis furent mises au pâturage où la numération résiduelle d’oeufs était très faible; leurs agneaux atteignirent au complet engraissement sans acquérir une charge vermineuse significative. Verabreichung von Thiabendazol an die Muttertiere vor dem Koitus hatte im folgenden Frühling niedrige fakale Eizahlen zur Folge. Die Schafweide enthielt nur einen niedrigen Rückstand von Larven und die Lämmer mästeten ohne eine bedeutsame Wurminfestation zu erwerben. El tratamiento de las ovejas con el Thiabendazole antes de la monta resultó en una baja numeración de huevos fecales la primavera siguiente. Las ovejas se han hecho pastar sobre terreno con una numeración residual de larvas muy baja y los carneros han engordado satisfactoriamente sin adquirir una carga significativa de nematodas.