Endo-parasitic infection patterns in angora goats and merino sheep kept in a fibre animal farm in Central Italy

Sheep breeding and extensive cattle husbandry, once constituting an important zootechnical branch in Italy, now face extinction in many areas. The inconveniences connected to the breeder life style, such as the necessity to care for the animals 7 days a week and outside common working hours, are not rewarded with an acceptable income. Rendering sheep and goat breeding more profitable by switching to fibre-producing species may be a strategy to reverse this trend. Precious mixed fibres can be yielded by merino sheep, angora goats and alpacas reared together. However, health management requirements may differ according to the species. This study compares internal parasitoses in angora goats and merino sheep, reared together with alpacas on a farm (Maridiana, Umbertide) in Central Italy. During the study year 2003, the flock was composed of about 20 merino sheep and 60 angora goats. The animals were kept in mixed groups, separated by sex, at a density of 7.6 animals/ha. Pastures were used all year round and recovery of the animals in shelters was practiced at night and in adverse weather conditions. All goats and sheep were included in the longitudinal study and faecal samples from the rectum were taken each month. The identification and quantification of oocysts, eggs and larvae was performed according to the standard procedures of copromicroscopy. Totally 634 faecal samples were examined from angora goats and 200 samples from merino sheep. Antihelmintic (ivermectin, benzimidazole) and anti-coccidian (sulfadimetoxine-trimetoprime) treatments were administered to all animals twice and once a year, respectively. Pasture rotation and good sanitation in shelters was practiced to reduce the transmission of parasitic disease agents. Helminthic infections were very common in both merino sheep and angora goats. In 83.5% (CI95 78.3-88.7) and 96.6% (CI95 94.0-97.2) of the respective faecal samples, eggs or larvae were found. In merino sheep, the more frequently encountered helminths were gastro-intestinal strongyles (78.5%; CI95 72.8-84.2) such as Trichostrongylus axei, T. vitrinus, Oesophagostomum spp., Cooperia spp., Haemonchus spp. and Ostertagia spp. In particular, Nematodirus spp. eggs were found in 26.5% (CI95 20.3-32.7) and Trichuris spp. eggs in 22.5% (CI95 16.7-28.3) of the faecal samples. Angora goats were infected at similar rates by intestinal strongyles (83.4%; CI95 80.5-86.3; OR 1.3 p=0.111) whereas their Trichuris infection rate (84.2%; CI95 81.4-87.1) was about 4 times higher than that of merino sheep (OR 18.4; p<10-4). In addition, larvae from lungworms (Dictyocaulus filaria, Protostrongylidae) were found more frequently (20.7%; CI95 17.5-23.8; OR 7.2 p<10-4) in angora goats, whereas faecal samples positive for Nematodirus eggs were relatively rare (6.6%; CI95 4.7-8.6; OR 0.196 p<10-4). Coccidian infections were also observed more often in goats than in sheep: oocysts from Eimeria intricata and other Eimeria spp. were found in 77.8% (CI95 74.5-81.0) and 56.5% (CI95 49.6-63.4; OR 2.7 p<10-4) of the samples from the respective animal species. The analysis of monthly prevalences per parasite genus (group) did not reveal any relation to season in either merino sheep or angora goats. Goats not only were more frequently infected than sheep, but they also harboured higher parasite loads. The geometric mean egg or oocysts per gram, calculated on the positive faecal samples of angora goats, amounted to 562 (CI95 434-640) for Eimeria spp., to 348 (CI95 318-381) for Trichuris spp., and to 269 (CI95 236-306) for intestinal strongyles. The respective values in merino sheep were about 1/2 for Eimeria spp. (t=5.23; p<10-4), 1/3 for Trichuris spp. (t=7.40; p<10-4), and 1/2 for strongyles (t=4.45; p<10-4). Accordingly, pathologic manifestations, such as anaemia, diarrhoea and weight loss, were sporadically reported by the breeder in goats but not in sheep. As the two species shared the same environment and received the same alimentation and anti-parasitic treatments, the differences in parasite prevalence and density appeared to be related to a relatively lower natural resistance of angora goats. Thus, especially where animals are kept at a rather high density, care should be taken to lower their exposure to infective larvae/eggs by frequent pasture rotation. Parasite loads should be regularly monitored, to intervene promptly with treatment if necessary.