Is gastrointestinal strongyle faecal egg count influenced by hour of sample collection and worm burden in goats?

Gastrointestinal (GI) strongyle infections remain one of the main constraints to goat production worldwide. Although several indicators of GI strongyle infections have been proposed, faecal egg count (FEC) techniques are the most common approaches for the estimation of prevalence and intensity of these parasites. However, FEC may be subjected to a within-individual variation due to factors such as weather, season, random day-to-day variation and phase of the parasitic infection. A longitudinal study of GI strongyle FEC was conducted on 63 dairy goats to evaluate the effects of hour of sample collection on FEC and the relationship between FEC and worm burden. The goats were naturally infected with Teladorsagia circumcincta, Haemonchus contortus, Trichostrongylus colubriformis and Oesophagostomum venulosum. Every 3 weeks for 14 months faeces were collected every 2 h for 24 h from three individually caged goats. The faeces were those passed by the goats during the 2 h preceding each collection. For each goat a sample from this material was analyzed using the Flotac double technique. To explore relationships between FECs and adult parasite counts, on the day following sampling, the three goats were euthanized and the nematodes present in the abomasa and intestines were recovered, identified and counted. The results of the general linear model did not show any significant effect of the hour of faecal sample collection on GI strongyle FEC, whereas a significant effect of the month of faecal sample collection was found. The results of the Pearson correlation showed a significant (P=0.000) positive relationship between FEC and worm burden (r=0.6), in particular regarding H. contortus (r=0.9). In conclusion, the present study showed that the hour of sample collection does not influence the GI strongyle FEC and that there is a good relationship between FEC and total GI strongyle worm burden in goats.

Economic efficacy of anthelmintic treatments in dairy sheep naturally infected by gastrointestinal strongyles.

The aim of the present paper was to assess benefit of strategic anthelmintic treatments on milk production in six commercial dairy sheep farms, located in southern Italy, whose animals were naturally infected with gastrointestinal strongyles. On each farm, two similar groups were formed, one untreated control group and one treated group. In all the treated groups, the strategic anthelmintic schemes were based on: (i) only one treatment with moxidectin in the periparturient period (February, Farm No. 6), or; (ii) two treatments, i.e. the first with moxidectin performed in the periparturient period (February, Farms Nos. 1, 2, 3 and 4) or in the postparturient period (April, Farm No. 5), and the second with netobimin at the mid/end of lactation (June, Farms Nos. 1, 2, 3, 4 and 5). Faecal egg count reduction (FECR) tests were performed on each farm in order to asses the anthelmintic efficacy of the drugs used. In addition, milk yield measurements for each animal fortnightly in each farm for the lactation period were performed. In terms of FECR, both moxidectin and netobimin were effective in all the 6 studied farms. Regarding milk production, overall in the 6 study farms the mean daily milk productions of the treated groups were higher than those of the control group. However, there were important differences between the 6 farms, i.e. the increase of milk production in the treated groups versus the control groups was as follows: +18.9% (Farm 1), +30.4% (Farm 2), +4.0% (Farm 3), +37.0% (Farm 4), +5.5% (Farm 5) and +40.8% (Farm 6). The results of the study showed that the economic efficacy of an anthelmintic treatment is not a cause-effect issue, but is a multifactorial issue which depends upon the quali-quantitative parasitological status of the animals, the pathogenesis of the species of parasites, the virulence of the strains of parasites, the local epidemiology, the timing of treatment, the breed of animal in terms of genetics and production types, nutrient supply.