Ascarid eggs disappear faster from gravel and wood chips than from soil.

1. Ascarids (Ascaridia galli and Heterakis spp.) are highly prevalent in free-range laying hens. Ascarid eggs survive for long periods in soil, and one preventive measure is to add litter material to areas close to the henhouse. In this study, recovery rates of ascarid eggs from three common litter materials, namely pea gravel, beech (Fagus sylvatica) and spruce (Picea abies) wood chips were compared to recovery rates from soil. 2. Materials were mixed with faeces containing 1,408 ascarid eggs per g of faeces, placed in plastic fruit boxes and exposed to natural weather conditions in a randomised block design with six replicates per treatment. 3. Numbers of ascarid eggs were quantified at 28 time points over 3.5 years. Ascarid eggs were recovered for over three years from all materials and completely disappeared during the fourth winter of exposure. Time needed to get to a 50% reduction in ascarid eggs did not differ between litter materials and soil (242 to 269 days). A 99% reduction was reached significantly (P < 0.001) earlier in pea gravel (548 days) than in the three other materials, and earlier in the two wood chips (day 682 for beech, day 692 for spruce, P < 0.05) than in soil (1,277 days). 4. Accumulation of ascarid eggs in the area close to the henhouse can be reduced by any of the tested litter materials compared to bare soil. Adding litter to this area is highly recommended for free-range layer farmers in order to reduce numbers of infective ascarid eggs.

Integrated control of gastrointestinal nematodes in lambs using a bioactive feed × breed approach.

Forages rich in condensed tannins have repeatedly shown potential to reduce gastrointestinal nematode infection in sheep. Similarly, several breeds of sheep have shown a relative resistance to gastrointestinal nematodes (GIN). We hypothesised that additive or even synergic effects may arise from the combination of a relatively resistant breed and a diet rich in condensed tannins. In study I, 160 lambs of the native Red Engadine Sheep (RES) and 113 lambs of the Swiss White Alpine sheep (SWA) were artificially infected with GIN and subsequently grazed for 52 days. The lambs were then distributed to 2 groups for a 14-day experimental feeding period. One group received a diet with a proportion of 55% sainfoin and was compared to a control group on the basis of faecal egg counts (FEC). In study II, 25 RES and 27 SWA lambs grazed infectious pastures for 37 days and were subsequently fed for 13 consecutive days with approximately 100% sainfoin or control forage. In addition to the FEC determination at the start and the end of the experimental feeding, the 52 lambs in study II were slaughtered and necropsied to determine their worm burden. FEC at the end of the feeding period were significantly lower in sainfoin fed lambs compared to controls in study I (p<0.001) as well as in study II (p=0.012). Breed, animal age, live weight, sex and the interaction of breed and treatment did not affect FEC in either study. The main nematode genera found in the sacrificed lambs of study II were Haemonchus spp., Teladorsagia spp., Nematodirus spp. and Trichostrongylus spp. Overall, RES had a significantly lower Haemonchus spp. (p=0.035) and Trichostrongylus spp. (p=0.003) worm burden compared to SWA. Regardless of breed, sainfoin feeding significantly reduced Teladorsagia spp. (p=0.049) and Nematodirus spp. (p<0.001) worm burden. Although, we could not demonstrate additive or synergic effects when using an integrated breed × sainfoin approach, the finding that a proportion of only 55% sainfoin in the diet led to a lower FEC compared to controls is important with respect to the implementation on producing farms.

Poultry litter as a source of gastrointestinal helminth infections.

The aim of this study carried out in 6 commercial layer houses was to examine the effect of litter management on water content, helminth egg count and litter infectiousness with the intestinal nematodes Ascaridia galli, Heterakis gallinarum, and Capillaria spp. Three types of litter management were established in each layer house in parallel: in compartment A, litter was left undisturbed, in compartment B, wet litter was replaced and in compartment C, new litter material was added weekly. Dry matter (DM) contents of the litter and parasitological parameters (helminth egg concentration in litter samples, faecal egg counts (FECs) in the permanent layer flocks, helminth prevalence and burdens in two series of tracer animals) were determined every 4 weeks during the first 32 weeks of one laying period. DM contents of the litter varied in a broad range (48-95%); 8 weeks after onset of the study, there were significant differences between sites (P<0.001) but not between management regimes. A. galli/H. gallinarum eggs were isolated from 91% of the litter samples, whereas eggs of Capillaria spp. were only extracted from 13% of the samples. Egg concentrations in litter remained at a similar level during the observation period. Neither management regime reduced helminth egg concentrations in the litter compared to the unmanaged regime. Laying hens started excreting helminth eggs 8 weeks after introduction to the layer house. In treatment C (litter added) FECs were lower than in the unmanaged treatment A in weeks 8 (P<0.0001), 20, and 28 (both P<0.1). There was no correlation between the concentration of helminth eggs in the litter and the FECs of the layer flocks. The prevalence of A. galli in tracer animals was lower (<10%) than the prevalences of H. gallinarum (68-80%) and Capillaria spp. (30-58%). Prevalences and H. gallinarum burdens did not differ significantly between management regimes. Although high helminth egg concentrations were found in litter, the prevalence and worm burdens in tracer animals were low compared to a similar study with tracers kept in poultry runs. The reasons for this may be that poultry litter negatively affects viability and infectiousness of helminth eggs. However, underlying mechanisms need to be clarified.