The effects of windrow composting on the viability of Parascaris equorum eggs.

This scientific research examines how the process of windrow composting can affect the viability of eggs of the parasitic worm Parascaris equorum, typically found in young horses. The study found that windrow composting effectively rendered the P. equorum eggs non-viable, making it a potentially useful method for controlling the spread of this parasite on horse farms.

Research Methods and Design

• The study was conducted on a working horse farm in Kentucky.
• Three grams of feces, each containing about 2216 P. equorum eggs, were sealed in filter bag sentinel chambers for the experiment.
• These sentinel chambers were exposed to three different treatments: continuous or intermittent exposure to the interior of the windrow compost heap, while control samples were stored at 4°C.
• These methods allowed researchers to evaluate the effectiveness of windrow composting on the viability of P. equorum eggs under different conditions.

Experiment Process and Results

• At the beginning of the experiment, the filter-bag sentinel chambers were placed at the center of 10 locations within the compost windrow.
• In subsequent days, any chambers in the ‘constant exposure’ treatment were returned to the compost windrow’s interior, while those in the ‘intermittent exposure’ treatment alternated between being on top of, or inside, the compost windrow.
• Samples were taken from each chamber at regular intervals over an 18-day period and incubated at room temperature for 21 days for further analysis.
• The eggs were retrieved from the chambers using a method called double centrifugation flotation and examined under a microscope. The viability of eggs was assessed by whether or not they had developed to the larval stage (embryonation).
• The findings indicated that by day 8, none of the P. equorum eggs in the ‘constant exposure’ treatment were viable, while for the ‘intermittent exposure’ treatment, eggs became non-viable by day 6.
• In contrast, the control samples maintained a viability rate above 79% throughout the examination period.
• The study used a mixed linear model with repeated measures to assess the influences of the day of the experiment and the compost treatment on egg viability.

Conclusion and Implication of the Findings

• The research demonstrated a significant reduction in the viability of P. equorum eggs when exposed to constant or intermittent composting treatment.
• The authors conclude that windrow composting could serve as an effective means of controlling the spread of P. equorum in horse farms, thereby protecting young horses from the severe pathological impacts of the parasite.
• However, it is important to note that these results are based on the specific conditions of this single horse farm. More research may be required to determine how universal these results could be in varying conditions across different horse farms.