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Aim:Gastrointestinal (GI) nematodes are considered as a major constraint for successful sheep production. Control of these parasites heavily relies on the use of chemical anthelmintics. Over the past decades, the development of anthelmintic resistance to various groups of anthelmintics and problem of drug residues in animal products has awakened interest in medicinal plants as an alternative source of anthelmintics. Hence, this study was undertaken to evaluate the anthelmintic efficacy of Indigofera tinctoria by scientifically validated in vitro and in vivo tests approved by the World Association for the Advancement of Veterinary Parasitology.Materials and Methods:In vitro assays such as egg hatch assay for ovicidal and larval migration inhibition and larval development assay for larvicidal properties were used to investigate in vitro effect of extracts on strongyle egg and larvae, respectively. Fecal egg count reduction test was conducted in vivo to evaluate the therapeutic efficacy of the extracts administered orally at dose rates of 125, 250, 500 mg/kg to sheep naturally infected with mixed GI nematodes.Results:Ethanolic extract of I. tinctoria demonstrated significant (p<0.01) inhibition on egg hatching at concentrations of 40 mg/ml and 80 mg/ml. In in vivo assay, the ethanolic extract of I. tinctoria reduced the fecal egg count ranging between 30.82% and 47.78% at various doses (125, 250 and 500 mg/kg). Although there was a slight variation, all the hematological parameters were within the normal range reported for sheep. Except for alanine transaminase, the overall mean of all the serum biochemical profile was within the normal range for sheep.Conclusion:Based on the results obtained by in vitro and in vivo assay, the ethanolic extract of I. tinctoria possesses anthelmintic activity and could replace the chemical anthelmintics used presently.

A study was undertaken to assess the virulence of Marek's disease virus (MDV) serotype 1 field isolates obtained from poultry flocks of southern part of India. Five representative MDV serotype 1 strains were isolated from eighty-six blood samples collected from fifteen farms. Three out of five isolates which were free from avian leukosis virus (ALV) and reticuloendotheliosis virus (REV) were adapted in chicken embryo fibroblast (CEF) culture and designated as Ind/TN/11/01, Ind/KA/12/02 and Ind/TN/12/03. Pathotyping assay was conducted in two trials. In the first trial, non-vaccinated chickens were challenged (trial I), while in second trial, two types of vaccinated chickens along with non-vaccinated controls were challenged (trial II). Birds inoculated with field isolate Ind/TN/12/03 had very low body (75.34±3.04 g 15 days post infection (dpi)) and bursa Fabricii weight (1.64±0.06 at 15 dpi) when compared to those inoculated with the other two isolates (Ind/TN/11/01 and Ind/KA/12/02) and uninoculated controls (body weight 111.33±1.30 g and bursa Fabricii weight 4.33±0.11 15 dpi). Incidence of early mortality syndrome (53%) and lymphoma (86%) induced by Ind/ TN/12/03 was comparable with very virulent strains published elsewhere. In protection test, the percentage of Marek's disease (MD) incidence induced by Ind/TN/12/03 was 57.5% and 25% in monovalent and bivalent vaccine inoculated birds respectively compared to uninoculated control (100%). Based on the above findings in pathotyping experimental trials with a supportive evidence of histopathological observations, isolate Ind/ TN/12/03 was considered as very virulent MDV and other two isolates were considered as virulent MDVs.

Poultry farms in and around Namakkal with a history of tapeworm infection were surveyed for the presence of beetles which could act as intermediate host for the tapeworms. Beetles collected from different poultry farms with suspected tapeworm infection were examined for the presence of metacestode stage of the parasite. A total of 1,880 beetles were collected from 12 poultry farms with suspected tapeworm infection to study the vector potentiality. Out of these, 205 beetles (10.9 %) from nine farms were found to harbour cysticercoids. The percentage of cysticercoid infection in beetles was 8.24, 10.34 and 16.66 % respectively in three different surveys. The beetles harbouring the cysticercoids were identified as Opatroides frater, which may be a natural intermediate host for Raillietina cesticillus. Infection free young chicks (4 weeks old) were experimentally infected with specific number of cysticercoids and prepatent period of tapeworms was found to be between 12 and 13 days. Gravid segments were expelled between 3 and 4 p.m. consistently. The results of this study would help to formulate suitable control measures against the above tapeworm infection.

Aim: A trial was conducted to assess the influence of parasitic load on the lambs reared under the intensive system, continuous grazing, and rotational grazing systems of management. Materials and Methods: A total of thirty numbers of the undetermined breed of ewe lambs around 4-5 months of age were randomly selected and allotted to three treatment groups: T1 (intensive system - control), T2 (rotational grazing), and T3 (continuous grazing). The T1 group lambs were raised under a stall-fed system of management, the T2 group lambs were grazed under rotational grazing strategy in four paddocks of plot-A, while the T3 group lambs were continuously grazed in plot-B. Results: At the end of the study, there was a highly significant difference (p=0.01) in the fortnightly strongyle egg count per gram (EPG) of feces among the lambs pertaining to the three treatment groups; the lambs in T3 had a higher strongyle EPG compared to T2 lambs. With regard to the overall reduction in EPG from the initial count, lambs under rotational grazing showed the maximum decrease of 54.52% compared to lambs under T3 (continuous grazing). There was a strong positive correlation noticed between the mean temperature of the day at each fortnight and the subsequent EPG at each fortnight with R2=0.87. There was a strong positive correlation noticed between mean FAMACHA® scores and the EPG with R2=0.84, R2=0.83, and R2=0.83 for T1, T2, and T3, respectively. Conclusion: The grazing management with pasture rotation should be considered as a viable option for sustainable parasitic control in case of grazing-dependent livestock husbandry in India.