Decreasing small ruminant exposure to parasites by reducing slug and snail populations through a sheep/duck grazing system

Decreasing small ruminant exposure to parasites by reducing slug and snail populations through a sheep/duck grazing system

Summary

This project aims to explore the potential benefits of multi-species grazing of sheep with ducks in order to address the parasite Parelaphostrongylus tenuis (P. tenuis, a.k.a brain worm/deer worm). This parasite is transmitted to sheep through deer and then slugs/snails before affecting sheep. Infection often leads to paralysis and death of the affected sheep. In the past, we’ve demonstrated that ducks can reduce slug populations that are a pest to shiitake mushroom production (Project FNE12-745)

Our goals for the project are to:

Objective 1: Determine if grazing 50 ducks reduces gastropod populations in paddocks ~12,000 square feet

Objective 2: Reduce brain worm parasite risk to grazing ruminants, thereby reducing the need for Ivomec, dexamethasone, and Safeguard

Objective 3: Determine ideal timing of leader-follower rotation that results in low gastropod population, minimal duck poop presence on pasture, and diverse and abundant forage

Due to the historic D3 drought in our region this season, we opted to delay the start of monitoring slug populations to the 2017 and 2018 seasons. Our past experience meant we knew the work would produce less than valuable results, because slug populations are virtually non-existent during dry times. Additionally, the drought conditions meant that pasture did not grow after the sheep’s first rotation in May. We spent 2016 reorganizing our grazing system to accommodate drought and make use of hedgerows, which will help tremendously as we set out to collect data over the next two seasons.

Objectives/Performance Targets

Our main accomplishment relative to the grant in 2016 was establishing a more robust grazing system, including the implementation of a grazing map and chart, where we numbered paddocks and documented our pattern of movement. Because the timing of the sheep rotation relative to the duck rotation is so critical to a successful study, we found it beneficial to get this aspect of management underway this season, without also trying to collect data. We also have a more uniform paddock system that will facilitate more accurate results in 2017 & 2018.

Much of the work and research laid out in the grant is still to be done. We will push this to the 2017 and 2018 seasons, where we will actually trial the rotations and monitor for slug populations. Delaying this because of the drought will likely provide more meaningful results from the study as a whole.

Accomplishments/Milestones

We did lose one sheep to the P. Tenuis parasite in 2016, a previous infection from 2015 that was not treatable. No new sheep were infected, possibly because of the extreme drought and thus poor parasite conditions.

The original project leader Elizabeth has brought in co-owner and husband Steve Gabriel to share the lead will be responsible for all aspects of implementing, monitoring, and reporting for the project.

Collaborators: