Teladorsagia circumcinta specific antibody responses in two goat breeds with differing susceptibilities to gastro-intestinal nematode infection

Serum and faecal samples were taken monthly from 60 goats of two different dairy breeds (30 Alpine and 30 Nera di Verzasca) belonging to the same herd over a 9 month period from April to December 2010. Goats were milked twice daily and during the rest of the day were free to graze and browse in a large mountain area from 900 to 1550 m above sea level from March to November; they were in the fold during the winter months. Trichostrongyle faecal egg counts (FEC) were performed using FLOTAC double technique with NaCl solution. Teladorsagia circumcincta specific IgA and IgE levels within the serum were quantified by indirect ELISA. FEC values were significantly higher in the Alpine breed, and varied significantly among months, with a peak of emission in April for both breeds and a second peak in December only for Alpine goats, suggesting that the Alpine breed is more susceptible to trichostrongyle nematode infections. Both IgA and IgE levels varied significantly over time (P < 0.001), however, only IgA levels were significantly different between the two breeds (P = 0.013), with higher levels of IgA present in the Alpine breed. These results suggest that increased levels of T. circumcincta-specific IgA in the Alpine breed may be related to increased parasite burden, and that the increased resistance to trichostronglye nematode infection seen in the Nera di Verzasca breed does not appear to be related to levels of circulating T. circumcincta-specific IgA or IgE.