The Use of Rotational Grazing And Two Herbal Treatments To Control Parasitism In Sheep And Goats

RESEARCH & EDUCTION

By Ann Wells, DVM

Introduction

“ ... good management and animal selection can provide much of the needed control against internal parasites for all livestock, including cattle. However, we also know we need effective alternative treatments during times such as mild, wet summers or when livestock are unavoidably stressed.”

Internal parasites are, notably, the biggest disease problem of sheep and goats. Warm, humid climates in the South allow internal parasites to thrive, causing disease for most months of the year. Anthelmintics used to kill these internal parasites are losing their effectiveness due to resistance of the parasite to the chemical compound. For sheep and goat producers to be profitable, these two problems must be solved. It is imperative that we design new management systems that include efficacious alternative therapies and practices. Organic and conventional management programs face the same problems.

While internal parasites are not as much of an overall problem for cattle, management of calves must include some parasite control. Alternative therapies are needed for conditions that overwhelm the grazing and management system.

This project grew out of three previous years’ work at the Heifer Ranch in central Arkansas, utilizing rotational grazing and animal selection techniques to reduce the level of parasitism and the need for chemical dewormers. The Ranch is interested in certifying the livestock as organic yet is concerned that parasites can’t be controlled without the use prohibited chemical dewormers. The Ranch also has internal parasites with multiple chemical resistance which has increased the urgency for different control strategies and therapies. A small trial was first carried out using a commercial dried herbal product on 16 goats, but it failed. A garlic juice product was then found to work sufficiently but was not evaluated in a controlled setting needed to clearly assess its efficacy.

Objective

The objective of this season-long study was to examine two grazing strategies and three deworming treatments for the control of gastrointestinal nematodes in sheep and goats.

Materials and methods

Location: Heifer Ranch, Perryville, AR:

61 Katahdin ewes lambed in March 2007
96 lambs grazed with dams on rotationally managed cool season forages (vetch, chicory, clovers) then warm season grasses, clover, and broad leaf forbs. One group of ewes with 28 lambs grazed chicory for 7 of 28 days monthly
Lambs weaned at 120 d of age
Treatments: Lambs were randomly assigned to groups treated with copper oxide wire particles (COWP), Garlic Barrier, or ground papaya seeds; one group was grazed on the chicory pasture
Lambs dewormed if FAMACHA score >3

Location: Cooperator farm in Marianna, AR

29 meat goat does and their kids rotationally grazed on 35 acres of cool season forages, warm season forages and crop aftermath, rotating weekly.
Buck kids weaned and removed but doe kids remained with does.
One enterprise within a larger vegetable gardening enterprise
Treatments: Randomly assigned goats dewormed with either papaya seeds or Ivermectin if
FAMACHA score > 3

Location: Cooperator farm in Wagoner, OK

50 ewes and lambs on 10 acres of pastureland reclaimed from neglected and brushy overgrowth.
Rotation occurred every 5 days at start of project, reduced to daily in middle of project.
Treatments: Randomly assigned sheep dewormed with Garlic Barrier or Ivermectin
Sheep dewormed when FAMACHA score was > 3 at start of project, reduced to FAMACHA score ≥ 3 in middle of project.

Fecal egg counts (FEC) and FAMACHA scores were recorded every two weeks with FEC additionally recorded 7 days post treatment. Animals were visually evaluated daily.

FAMACHA scores determine only the level of Haemonchus contortus infestation and thus only useful in small ruminant operations.

Results

Heifer Ranch

3 dewormed with COWP with a 0 – 70% reduction in FEC
3 dewormed with garlic with a 48 – 95% reduction in FEC
3 dewormed with papaya with a 0 – 100% reduction in FEC
18% of lambs required deworming but there were no post treatment samples collected 7 days later, so that data is not included in the results above.
No effect of rotational grazing management on FEC or FAMACHA score
11 deaths: 5 related to parasites, 6 went missing, although the presumption is that parasites had a role in their disappearance.
6.3% of those grazed on chicory died, while 11.9% of those in the control grazing system died.
2 of the 3 lambs treated with Garlic Barrier and 2 of the 3 lambs treated with COWP died while only one of the papaya seed group died.

Cooperator farm in Marianna, AR

Only two goats had a FAMACHA higher than 3 and only one of those was treated; from the papaya seed group with its FAMACHA score reduced after treatment

Cooperator farm in Wagoner, OK

19 sheep died, with 16 of them dying before July 15.
11 of 19 sheep were given Garlic Barrier, 8 were given chemical dewormers. Over the course of the summer, the chemical dewormer was changed three times, due to resistance of the parasites.
Excessively high rainfall occurred from May till July 15th.

A sire effect was seen at Heifer Ranch and the cooperator
farm in OK.

Discussion

This project gave us some useful results and insights. The goal is to have resilient animals who do not require treatment for internal parasites. There were too few sheep treated at Heifer Ranch to adequately determine efficacy of any of the alternative treatments, including the chicory grazing treatment. This can be seen as a success, even though more information is still needed to determine consistency in efficacy. We continue to see that management is the foundation for successful prevention of parasites in livestock. This was especially seen at the cooperator farm in Marianna, AR, where the low stocking rate and rotational system kept parasitism to a minimum.

The OK farm experienced above average rainfall, which greatly increased the number of parasites. We also discovered that these sheep had internal parasites with multiple chemical dewormer resistance.

Garlic Barrier, which has shown efficacy in previous drought years was not as effective in this high rainfall year. With higher than average rainfall in OK and at Heifer Ranch, FAMACHA testing had to be done bi-weekly to identify animals at an early stage of clinical parasitism.

We are more assured that good management and animal selection can provide much of the needed control against internal parasites for all livestock, including cattle. However, we also know we need effective alternative treatments during times such as mild, wet summers or when livestock are unavoidably stressed. Pasture plantings appear to have good promise or possibly products that can be harvested from those pasture plantings.

Future studies

This project will be repeated in 2008 at Heifer Ranch and at two Oklahoma farms, including the one that participated last year. Chicory will be grazed for a longer period of time. The papaya seed treatment will use an increased dose. Garlic will be used as a tonic but not as a dewormer. u

Dr. Ann Wells has more than 20 years experience in livestock production, including producing and selling natural lamb and now grass finished beef. Involved in organic livestock production on her own farm and working with other organic producers for 15 years, Dr. Wells has her own business, Springpond Holistic Animal Health, in Prairie Grove, AR. developing and educating on sustainable animal wellness plans for producers and educators.

Dr. Wells has been working with Heifer International for the last three years, researching parasite management strategies to reduce the need for anthelmintics. She also works with Heifer projects in the U.S. to improve their livestock production by focusing on animal well-being. Her philosophy is to focus on the health of the animal through controlled grazing management and stress reduction techniques and strategies.

Contact Ann by email: annw@pgtc.com