Abstract

SUAREZ, V.H et al. Epidemiología de los nematodes gastrointestinales en caprinos lecheros en los valles templados del NOA, Argentina. RIA. Rev. investig. agropecu. [online]. 2013, vol.39, n.2, pp.191-197. ISSN 1669-2314.

Forty onedairy goats were studied during milking from 4-Oct-2010 until 26-May-2011, to evaluate the epidemiology and the effect of gastrointestinal nematodes (GIN) on naturally infested goat milked on artificially irrigated systems on Lerma Valley (Salta). Two groups of goats were monitored: PJ (n=17) kidding in June and PS (n=24) kidding in September. Only goats with high egg counts (>3000) or GIN infection signs were salvage treated. Milk yield was evaluated during april-2010 on two groups of 14 milked goats each one. One group was treated with moxidectin (MXD: 200 mcg/kg) and the other untreated. Test-day milk yield of individual goat was recorded before and 10 days after treatment. Faecal nematode egg counts (FEC), cultures for larval differentiation and Baermann technique were done monthly. In addition for evaluate pasture larvae availability, successive groups of worm free tracer kids were grazed with goats and then slaughtered for worm counts. Other death goats of the farm that were necropsied for worm counts. Least squares means analysis of vari􀀐 ance was conducted with a mixed model. At the start goat FEC of PJ were significantly (P<0,04) lower than those of PS until early summer. Then FEC of both groups equally and gradually decrease until late summer, when showed a significant (P<0,05) increase towards autumn. From faecal cultures Haemonchus (73,5%) predominates during spring and Haemonchus (55,5%) and Trichostrongylus (40,5%) towards autumn; always Teladorsagia (< 7%) was present with low percentages. Larvae availability on pastures recovered from tracer kids were significantly (P<0,002) higher from late December to April (rain period: RP) than from May to early December (dry period: DP). During the rain RP, 96,1% of the worms was recovered, whereas from the DP 3,9% was recuperated and the annual prevalence of Haemonchus and Trichostrongylus was respectively of 31% and 63%. Treated goats with moxidectin (200 mcg/kg, SC) showed a significant (P<0,02) increase of 15% on milk yield; moxidectin had an efficacy of 82,8%. Preliminary conclusions showed that Haemonchus contortus and Trichostrongylus colubriformis were the most pathogen nematodes for goats in the temperate valleys of the Northwest of Argentina; the risk period goes from early summer to middle autumn and artificially irrigation brings favourable conditions for nematode survival during the dry period.

Keywords : Dairy goat; Gastrointestinal nematodes; Epidemiology; Northwest of Argentina.

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