No loss of production due to larval challenge in sheep given continuous anthelmintic treatment via a controlled release capsule

Scientometric Analysis of Gastrointestinal Parasites Prevalence in Sheep and Goats of India

PURPOSE

In the present study, gastrointestinal parasites (GIP) prevalence in sheep and goats from India was estimated by scientometrics.

METHODS

The GIP prevalence studies (86) reported during 1998-2021 was obtained from online databases, and offline literatures, meta-analysis was undertaken by using "meta" package in R-Software.

RESULTS

The pooled GIP prevalence in India was 65% (95% level CI 56-74%, PI 12-96%) in sheep, 74% (95% level CI 66-80%, PI 14-98%) in goats and 68% (95% level CI 62-73%, PI 15-96%) in sheep and goats. Period-wise analysis revealed a higher GIP prevalence during 1998-2010 than the recent periods. Among the zones, GIP prevalence was higher in the Central zone (79%) in sheep, North zone (82%) in goats, and Central zone (78%) in sheep and goats. Based on the state-wise analysis, a higher GIP prevalence was observed in Haryana for sheep, Himachal Pradesh for goats, and Uttarakhand for sheep and goats. In India, a higher prevalence was reported by nematodes than other parasite classes. Based on climatic regions, a higher GIP prevalence was observed in semi-arid Steppe type region (84%).

CONCLUSION

The high prevalence zones, states, species, sample types, parasite classes, parasite species and climate regions of GIP will be useful in decision-making and resource use efficiency by policymakers and stake holders. There is an urgent need to prevent the occurrence of GIP infections in sheep and goats by adopting scientific management practices, effective therapeutic measures, and hygienic practices on farms to augment the economic benefits to sheep and goat farmers in India.

Integrated parasite management improves control of gastrointestinal nematodes in lamb production systems in a high summer-rainfall region, on the Northern Tablelands, New South Wales

This experiment tested the hypothesis that integrated parasite management (IPM) programs would reduce the effects of gastrointestinal nematodes (GIN) in meat-breed lamb production systems on the Northern Tablelands of New South Wales. The experiment was a longitudinal experiment using twin-bearing Border Leicester × Merino ewes on farms managed in accordance to either regional WormBoss IPM programs (n = 3 farms) or typical (TYP) regional GIN control (n = 2 farms). Ewes on each farm were either GIN-suppressed (SUP; n = 120 ewes) or not (NSUP; n = 120 ewes) and were managed in two groups (n = 120/group) balanced for GIN control. Ewes lambed in September and at lamb marking, 120 lambs (Dorset sires) from each ewe GIN control group were enrolled in the experiment to investigate the effect of ewe GIN control on lamb performance up to weaning. Overall mean worm egg count (WEC) of ewes (P = 0.004) was lower with IPM (IPM 766 vs TYP 931 epg) and was achieved with fewer drenches (IPM 4.5 vs TYP 5.5/year). Despite lower WEC, GIN infection reduced liveweight (IPM –2.1 kg vs TYP –1.1 kg, P = 0.0006) and clean fleece weight (IPM –0.11 kg vs TYP –0.01 kg, P = 0.03) of ewes to a greater extent on IPM farms. The annual rate of apparent ewe mortality was 6.5% and this was unaffected by GIN infection. WEC of lambs at weaning was lower on IPM farms (IPM 159 epg vs TYP 322, P < 0.0001) but the difference in weaning weights of lambs reared by NSUP and SUP ewes was greater on IPM farms (IPM –1.1 kg vs TYP 0.2 kg, P < 0.0001). Overall, the production loss due to GIN infection in these sheep-meat production systems, on the Northern Tablelands of New South Wales, was small and treatment frequency can be reduced by IPM programs.

Effect of gastro-intestinal nematode infection on sheep performance: a systematic review and meta-analysis

Background

Gastrointestinal nematode (GIN) infections are common in domestic sheep and impact directly and indirectly on the health of infected animals as well as on the associated economic production. In this study, we aim at summarizing the current knowledge on the influence of GIN infections on sheep production by conducting a systematic review. A subsequent meta-analysis of relevant studies was performed to provide an estimate of the effect of GIN infections on weight gain, wool production and milk yield.

Methods

A literature search was performed on the CAB, Pubmed and Web of Science database for the period 1960–2012. Inclusion criteria were: 1) Measurement of at least one production parameter. 2) Comparison between groups of sheep with different nematode burdens. 3) Same conditions regarding all aspects except parasite burden between groups. 4) Quantitative measurements of one or more production traits.

Results

Altogether, 88 studies describing 218 trials were included in this review. The majority of studies (86 %) reported that GIN infections had a negative effect on production but this was reported to be statistically significant in only 43 % of the studies. Meta-analysis indicated that performances of sheep infected with nematodes was 85, 90 and 78 % of the performance in uninfected individuals for weight gain, wool production and milk yield respectively. Our results suggest a possible reporting bias or small study effect for the estimation of the impact of GIN infections on weight gain. Finally, a general linear model provided an estimate for the decrease in weight gain in relation to the increase in faecal egg count of nematodes.

Conclusion

This study underlines the importance of GIN infections for sheep production and highlights the need to improve parasite management in sheep, in particular in face of challenges such as anthelmintic resistance.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-1164-z) contains supplementary material, which is available to authorized users.

Voluntary intake of a medicated feed block by grazing sheep is increased by gastrointestinal nematode infection

The aim of this study was to determine the rate, variability and repeatability of intake by grazing sheep of a medicated feed block (MFB) containing fenbendazole and investigate if infection with gastrointestinal nematodes altered consumption patterns of the MFB in the same grazing mob. In Experiment 1, 30 Merino wethers were given access to an MFB for two separate 1-week periods, with blood sampling at Days 2, 4 and 6 of each period to determine MFB intake. In Experiment 2, the wethers were selected based on previous MFB intake and allocated to receive an oral dose of 10 000 Trichostrongylus colubriformis and 3000 Haemonchus contortus (anthelmintic susceptible) or a long acting anthelmintic. After 5 weeks, sheep were given access to an MFB (1.5 mg fenbendazole/g) and eight blood samples were taken over 2 weeks to determine intake. In Experiment 1, individual MFB intake in Week 1 and Week 2 was positively correlated (P = 0.002, R2 = 0.287). Mean individual MFB intake in Experiment 1 and Experiment 2 was positively correlated (P = 0.008, R2 = 0.047). In Experiment 2, more infected wethers (95%) consumed the MFB than did uninfected wethers (79%) (P < 0.001) and infected wethers ate significantly more MFB over the first 4 days (P = 0.041) of access. All infected sheep consumed sufficient MFB to receive a therapeutic dose and worm egg counts in infected sheep declined from 2165 epg to 120 epg in the first week of access to MFB. The decline in differences in MFB intake between infected and uninfected sheep corresponded to the decline in worm egg count, suggesting the existence of self-medication with parasitism accounting for intake differences.