Extension & Research Project: Application of New Concepts for Control of Internal Parasites in Sheep and Goats

Sheep & goat farming are both economically and environmentally sustainable uses of the abundant forage resources in NY. By some estimates there are potentially millions of unused acres available for pasture and hay production. Complemented with the strongest regional market in the US (prices for market animals have been at record high levels for over two years), this indicates that there is a very high potential for expansion to supply the high number of consumers of sheep and goat products in NY with locally-grown product. Two major internal parasites of sheep and goats kept on pasture cause devastating losses in many flocks and herds. Haemonchus contortus (barber pole worm, stomach worm) is ubiquitous in sheep and goat herds. This organism consumes blood from the animal, causing anemia, and must be managed carefully to prevent it from developing resistance to the limited classes of anthelmintics (dewormers) that are available. Parelaphostrongylus tenuis (meningeal worm, deer worm, P. tenuis) has a life cycle involving white-tailed deer (which are unaffected) and snails or slugs. This organism can be ingested from snails or their tracks on forage consumed by sheep or goats. It then migrates to the spinal cord, causing inflammation and paralysis, particularly in young animals that have yet to develop immunity.

Extension objectives

  1. Better inform farmers and Extension Educators by writing paper and web-based bulletins on 1) practical methods for control of deer worm and barber pole worm in sheep and goats and 2) common misconceptions about deer worm lifecycles and transmission.
  2. Train farmers and extension educators in integrated parasite management by conducting workshops based upon 1) the FAMACHA system of controlling barber pole worm to minimize anthelmintic resistance in sheep and goats, and 2) recent research on the success of specific evasive grazing practices even in temperate climates to reduce frequency of anthelmintic use and prolong anthelmintic effectiveness.
  3. Update farmers, Extension Educators and veterinarians about ongoing research to control deer worm and barber pole worm.

Research objectives

  1. Document the incidence and age/season of infection of sheep with deer worm in the Cornell Teaching & Research Center flock.
  2. Field test protocols for treating goats and sheep showing symptoms of deer worm infection and track age/season of infection in participating herds/flocks.
  3. In preparation for vaccine development, demonstrate that sheep become resistant to deer worm by establishing infections followed by challenges to test for resistance using larvae and antigens available from Cornell’s colony of deer worm infected snails.
  4. Field test copper oxide wire particles to control barber pole worm on New York sheep and goat farms over a range of grazing management systems.
Leaders

  • Dr. Michael L. Thonney, Professor, Department of Animal Science, CALS, Cornell University
  • Dr. Judith A. Appleton, Professor, Baker Institute and CVM Administration, CVM, Cornell University
  • Dr. Dwight D. Bowman, Professor, Department of Microbiology & Immunology, CVM, Cornell University
  • Dr. Mary C. Smith, Professor, Department of Population Medicine & Diagnostic Sciences, CVM, Cornell University
  • Dr. tatiana Stanton, Extension Associate, Department of Animal Science, CALS, Cornell University
Summary
In this Cornell Cooperative Extension part of the project, the focus is on education and on-farm testing of three particular methods of internal parasite control. We have partnered with county extension educators, veterinarians, and other information extenders to hold seminars and workshops to reduce the reliance on anthelmintic deworming. This will help to prevent worm resistance and preserve these drugs for emergency use. During the past 3 years, we have conducted on-farm studies to test 1) the effectiveness of dosing sheep and goats with copper oxide wire particles (COWP) to control Haemonchus contortus, 2) whether establishing and grazing birdsfoot trefoil pastures has potential to control Haemonchus contortus and other round worms, and 3) testing whether ivermectin should be included in the arsenal of treatments of animals infected with deer-worm. Results of the COWP studies have been mixed. Dosing with COWP has been highly effective to control Haemonchus contortus on some farms and has had no significant effect on others. Further analyses of our 3 years of data and comparisons of worm populations, timing and extent of infection, breed and age of animals, and mineral/feed management among farms will help us determine what factors influence the effectiveness of COWP in different flocks. Some of the data analysis is reported in the Research progress section of this web site. The research on grazing birdsfoot trefoil to control round worms in sheep and goats is a multistate study. Cornell is responsible for the extension portion and 10 of 11 on-farm studies are being conducted in NY. Thus far, only one farm has had major problems with establishment (due to rotting of forage from extremely wet conditions during growth and weed competition). Very preliminary analysis of 5 grazing studies conducted in 2015 indicate that animals grazing BFT may be more resilient to Haemonchus contortus infection. The deer worm on-farm study terminated December 15, 2015 and some results are reported in the Research progress section of this web site. Analysis of the data so far indicates that inclusion of ivermectin in protocols did not significantly improve animal recovery at the completion of the 5-day treatment. We are still completing analysis to see if actual recovery one year after deer worm infection is affected by the treatment administered in this double-blind study. There has been significant farmer, extension educator, and veterinarian interest and participation in this project. We maintain wide communication about it and other needs of goat and sheep farmers through workshops, web sites, list servers and many direct email enquiries.
Impacts and outcomes
Interest in our study results and the critical topic of parasite control in small ruminants is very strong as evidenced by good attendance at our field days and workshops and invitations to speak at winter conferences. We are seeing several repeat participants at our outreach activities and these repeaters seem especially aware of limitations in BFT and COWP use and the importance of selective deworming and evasive grazing techniques. In total, 744 people have attended our integrated parasite management workshops, field days and FAMACHA certification programs describing COWP and other innovative parasite control methods with potential to help control worms. A total of 335 people have been certified in FAMACHA scoring and approximately 422 farmers have provided follow up contact info to track how their parasite management changes.
Project evaluation
Pre- and post-quizzes to measure changes in knowledge about integrated parasite management were completed by participants at five of our parasite workshops. Average before and after results for the percentage of questions answered correctly changed from 55.2% to 77.5%. Approximately 41%, 42%, 55%, 59% and 60% of the participants, respectively, plan to adopt parasite management practices as a result of attending the workshops including implementing or improving FAMACHA scoring, fecal egg counting, selective deworming and smart drug use, as well as several pasture management practices including improved rotation, lower animal density, mixed species grazing, and use of condensed tannin forages. A follow up survey to evaluate practices adopted or improved as well as economic and production impacts has been drafted by Extension staff and heavily edited. It will be administered during Winter 2016 to those program participants who have agreed to provide contact information (total to date ~ 422 participants – will be fewer once we edit for duplicates and members of the same farm), and who have had sufficient time to begin implementing new parasite control practices and/or documenting improvements as a result of their education. The survey will be administered online, or in hard copy format or by phone if preferred by the producer. An invitation to participate in this follow up questionnaire asking about parasite management changes farmers have implemented will go out to our 2013, 2014 and 2015 workshop participants in Feb/Mar 2016.
Publications

2013
40 articles were updated or added in the educational resource section of the Cornell Sheep and Goat Marketing Website http://www.sheepgoatmarketing.info/education.php. Some of these articles were reprinted in various publications during the year. For example:  Stanton, T.L. “Direct on-farm marketing of slaughter lambs and goats.” Premier 1 Goat Newsletter September 2013. Print and online.

2014
Stanton, tatiana L. “Using copper oxide wire particles to help control barber pole worms on Northeast sheep and goat farms.” Country Folks Magazine, Sheep & Goat Issue, 12 May, 2014. Print, online.

Stanton, tatiana L. and others: Resources for the collaborative project, Forage-based Parasite Control in the Northeast for Sheep & Goats, online

Burdett, Holly and tatiana L. Stanton. “Establishing Birdsfoot Trefoil for Pasture and Hay: A Guide for USDA OREI Project Demonstration Farms”, April 2014. 6 pages. Print, online Stanton, tatiana L. and Holly Burdett. “Case studies of 4 farms planting birdsfoot trefoil pastures.” Sept 2014. 46 Slides. Online  

2015
Stanton, tatiana L. “Dealing with Frostbite on Newborn Lambs and Kids.” Country Folks Magazine, Sheep & Goat Issue, 10 August 2015. Print, online 21 October 2015 at eXtension

Stanton, tatiana L. “Tis the Season for Deer Worm.” Country Folks Magazine, Sheep & Goat Issue, 09 November 2015. Print, online

Communications

2013

  • Cornell small ruminant marketing list server – SRMarketing-L; list server; tatiana Stanton, co-moderator; sheep and goat farmers, extension educators, and dealers/buyers; 387 subscribers
  • Cornell livestock processing issues list server – LivestockProcessing-L; list server; tatiana Stanton, co-moderator; livestock and poultry farmers and processors, extension educators and meat proc. inspection staff; 248 subscribers
  • Cornell Adult Goat Extension Website; http://www.ansci.cornell.edu/goats; tatiana Stanton, content provider; goat farmers and extension educators; 49 daily page views, 29 unique daily page views.
  • Cornell Youth Goat Extension Website; http://www.ansci.cornell.edu/4H/goats; tatiana Stanton, content provider; goat youth, 4-H leaders and extension educators; 33 daily page views, 19 unique daily page views.
  • Cornell Sheep Extension Website; http://www.sheep.cornell.edu/; Michael L. Thonney, webmaster & content provider; sheep farmers and extension educators; 246 daily page views, 117 daily visits, 84 unique visitors daily.
  • Sheep Goat Marketing Information; www.sheepgoatmarketing.info; Updated and expanded educational resource section. Student helper contacted all processors listed in Marketing Directory and her updates to entries will be added in January 2014; tatiana Stanton, content provider; sheep and goat farmers, buyers, processors and educators; 147 daily page views, 55 daily visits, 44 unique visitors daily.

2014

  • Cornell small ruminant marketing list server – SRMarketing-L; list server; tatiana Stanton, co-moderator; sheep and goat farmers, extension educators, and dealers/buyers; 444 subscribers.
  • Cornell livestock processing issues list server – LivestockProcessing-L; list server; tatiana Stanton, co-moderator; livestock and poultry farmers and processors, extension educators and meat proc. inspection staff; 214 subscribers.
  • Cornell Adult Goat Extension Website; http://www.ansci.cornell.edu/goats; tatiana Stanton, content provider; goat farmers and extension educators; 50 daily page views, 30 unique daily page views, 19 unique visitors daily.
  • Cornell Youth Goat Extension Website; http://www.ansci.cornell.edu/4H/goats;  tatiana Stanton, content provider; goat youth, 4-H leaders and extension educators; 37 daily page views, 17 unique daily page views, 7 unique visitors daily.
  • Cornell Sheep Extension Website; http://www.sheep.cornell.edu; Michael L. Thonney, webmaster & content provider; sheep farmers and extension educators; 188 daily page views, 87 daily visits, 64 unique visitors daily.
  • Sheep Goat Marketing Information; www.sheepgoatmarketing.info; tatiana Stanton, content provider; sheep and goat farmers, buyers, processors and educators; 199 daily page views, 102 daily visits, 87 unique visitors daily.

2015

  • Cornell small ruminant marketing list server – SRMarketing-L@cornell.edu; tatiana Stanton, co-moderator; sheep and goat farmers, extension educators, and dealers/buyers; 457 subscribers.
  • Cornell livestock processing issues list server – LivestockProcessing@cornell.edu; tatiana Stanton, co-moderator; livestock and poultry farmers and processors, extension educators and meat proc. inspection staff; 217 subscribers.
  • List serv for communication between farmers on our Birdsfoot trefoil establishment and grazing trials and researchers and extension personnel – BIRDSFOOTTREFOILFARMERSTUDT-L@cornell.edu; 19 subscribers.
  • Cornell Adult Goat Extension Website; http://www.ansci.cornell.edu/goats; tatiana Stanton, content provider; goat farmers and extension educators; 42 daily page views, 29 unique daily page views, 19 unique visitors daily.
  • Cornell Youth Goat Extension Website; http://www.ansci.cornell.edu/4H/goats; tatiana  Stanton, content provider; goat youth, 4-H leaders and extension educators; 19 daily page views, 16 unique daily page views, 15 unique visitors daily.
  • Cornell Sheep Extension Website; http://www.sheep.cornell.edu/;  Michael L. Thonney, webmaster & content provider; sheep farmers and extension educators; This website was modernized and restructured beginning in October 2015, after the reporting period for this report. 173 daily page views, 83 daily visits, 62 unique visitors daily.
  • A new website “Application of New Concepts for Control of Internal Parasites in Sheep and Goats” is in development as part of the newly modernized Cornell Sheep Extension Website – http://sheep.cornell.edu/2170-2/. (this site)
  • Sheep Goat Marketing Information; www.sheepgoatmarketing.info; tatiana Stanton, content provider; sheep and goat farmers, buyers, processors and educators; 259 daily page views, 187 daily visits, 144 unique visitors daily.
2. Field test protocols for treating goats and sheep showing symptoms of P. tenuis infection and track age/season of infection in participating herds/flocks.

The double-blind A or B coding for treatment with ivermectin or not has not been broken, pending further analysis. But some obvious conclusions can be made from the raw data with 20 goats and 18 sheep treated. All 11 goats given treatment A showed improvement after 5 days of treatment. Of 9 goats given treatment B, 7 improved, 1 was unchanged, and 1 was worse. Of the 10 sheep given treatment A, 5 improved, 4 were unchanged, and 1 was worse at follow-up after treatment. Of the 8 sheep given treatment B, 4 showed improvement, 2 were unchanged, and 2 were worse at follow-up after treatment. A chi-square analysis of these numbers showed that the differences between treatments were not significant. Pending further analysis of more quantitative data, it seems unlikely that treating with ivermectin in addition to fenbendazole and dexamethasone (or flunixin meglumine for late pregnant animals), will improve the outcome for goats or sheep with symptoms of P. tenuis.

3. In preparation for vaccine development, demonstrate that sheep become resistant to P. tenuis by establishing infections followed by challenges to test for resistance using larvae and antigens available from Cornell's colony of P. tenuis infected snails.
Ewe lambs born in the March 2013 lambing season, were kept in the barn for the entire 2-year experiment to keep them from being naturally exposed to P. tenuis. Snails infected with L1 P. tenuis in the Appleton lab 90 days previously were harvested to recover L3 P. tenuis. In October 2013, 12 ewe lambs were each orally dosed with 20 L3 (stage 3 larvae) of P. tenuis to induce immunity (Infected). Of the 12 ewes, 1 showed signs of P. tenuis infection in December 2013. A video of her symptoms is available on-line. She was treated and recovered. 12 Control cohorts of the treated ewes were orally given the suspension, while 7 ewes were kept as Sentinels. Blood samples were collected by jugular venipuncture every two weeks through March 2014 and processed to detect P. tenuis antigens. These results were equivocal, with higher levels for Infected ewes compared with Control ewes, but levels in the Sentinel ewes were almost as high as those in Infected ewes. There was a shortage of L3 to challenge all of the Control and Infected ewes in October 2014. Instead, 4 of 12 Control ewes and 5 of 12 Infected ewes were challenged orally with 100 L3; the unchallenged ewes were given the suspension media. Thus, in this Second year of the experiment the Control ewes not challenged with P. tenuis were similar to the sentinal ewes that were never treated. Blood was collected the day before challenge with L3 and at days 7, 21, 35, 49, 63, 77, 91, 105, 119, 133, and 146 post-challenge and an ELISA (enzyme-linked immunosorbent assay) was used to determine relative concentrations of IgG antibodies to P. tenuis as assessed by optical density (OD). The OD values were 0.51 for unchallenged Control and 0.51 for Sentinel groups (± 0.009). These were compared by analysis of variance that used a statistical model including Challenge, Ewe within Challenge as a random effect, Days (post challenge including day -1) and the Challenge by Days interaction. Only the effect of ewe was different (P <0.001) and we chose to exclude Sentinel ewes from further analysis. No ewes demonstrated symptoms of P. tenuis infection in the second year. The ELISA OD values for P. tenuis antibodies in serum of the experimental ewes (Unchallenged Control, Challenged Control, Unchallenged Infected, Challenged Infected) were compared by analysis of variance that used a statistical model including Initial infection, Challenge, Ewe within Initial infection and Challenge as a random effect, Days (post challenge including day -1) and the Initial x Challenge, Initial x Days, Challenge x Days, and Initial x Challenge by Days interactions.

Figure 1. Effect of days post challenge on serum antibody concentrations to P. tenuis in ewes initially in control or a group treated with 20 L3 at 7 months of age and then with about half of each group challenged or not challenged with 100 L3 at 19 months of age (P < 0.001 for the Initial x Challenge x Day interaction using a repeated measures model with ewe as a random effect).

Figure 1. Effect of days post challenge on serum antibody concentrations to P. tenuis in ewes initially in control or a group treated with 20 L3 at 7 months of age and then with about half of each group challenged or not challenged with 100 L3 at 19 months of age (P < 0.001 for the Initial x Challenge x Day interaction using a repeated measures model with ewe as a random effect).

The Initial x Challenge by Days interaction (P < 0.001) indicated that immune responses with increasing days post-challenge were different among the 4 Initial x Challenge groups (Figure 1). Mean OD values (± 0.051) for antibody levels for unchallenged Control ewes did not change much with days post-challenge, varying between 0.46 on day -1 to a high of 0.54 on day 91 and settling on 0.52 by day 146. Challenged Control ewes demonstrated the effect of initial exposure to P. tenuis, starting at 0.34 on day -1, increasing rapidly to 0.88 on day 21, then to a high of 0.99 on day 91 and only declining to 0.88 by day 146. Mean OD values for antibody levels for unchallenged Infected ewes didn’t change much. Demonstrating an immune response to infection a year earlier; they started high at 0.81 on day -1, increased to 0.95 on day 105 and leveled off to 0.90 by day 146. Challenged Infected ewes demonstrated immunological memory to infection a year earlier; they started high at 0.64 on day -1, and dramatically increased to 1.18 on day 7 reaching a high of 1.27 on day 21, then declining to 1.00 on day 91 and to 0.87 on day 133, then settling to 0.96 on day 146. There was not much difference among the Infected and Challenged groups in OD values from day 77 to through 146, with averages of 0.93, 0.91, and 0.97 for Challenged Control, Unchallenged Infected, and Challenged Infected, respectively. In contrast the average OD value for Unchallenged Control ewes from day 77 through day 146 was 0.52. These results show that sheep develop immunity to P. tenuis that could protect them from the paralysis associated with consumption of forage with high concentrations of L3. Although Challenged Control ewes unexpectedly did not exhibit symptoms of infection with P. tenuis, the antibody response to challenge was typical for first exposure. Because dendritic cells in the skin are highly effective at presenting antigens to the immune system, it is likely that a vaccine prepared with killed P. tenuis L3 would be effective. This would require, feces from infected white tail deer, infection of a snail colony, and recovery of L3 P. tenuis. Alternatively, recombinantly-produced surface proteins on P. tenuis L3 could be tested for antigenicity and might make effective vaccines.

4. Field test copper oxide wire particles to control barber pole worm on New York sheep and goat farms over a range of grazing management systems.

2013

Goat dairy study. The commercial goat dairy farmer was unwilling to include a negative control group because control animals would likely have to have been chemically dewormed during the study and their milk discarded. Instead, 15 does were each assigned to the following copper oxide wire particle (COWP) dosages: 1 g/22 lb live weight (about 6 g/head), 1 g/head and 2 g/head. Representative milk samples were obtained with milk meters immediately before receiving COWP (Day 0), and again 14 and 42 days later. Milk samples were analyzed for copper using inductively coupled plasma-atomic emission spectroscopy. All does were fecal sampled and FAMACHA scored on days 0, 14, 28, and 42. FAMACHA scoring is a field method of checking for anemia (the primary symptom of barber pole worm infection) in small ruminants by comparing the color on the inside membrane of the lower eyelid to a standardized score card. Bulk fecal samples were also collected and grown out to identify larvae populations. The farmer reported on pasture management every 14 days. Blood samples were collected from all does on Day 42 to determine AST enzyme concentration, an indicator of copper toxicity. Fecal egg counts were transformed to natural log values and analyzed by analysis of variance using a model that included level of COWP, doe within COWP as a random effect, date of sampling, and the COWP x Date interaction (which was not significant).

There was no long term effect of COWP dosage on H. contortus fecal egg counts; geometric means were 1310, 1005, and 1305 for 1 g/22 lb live weight, 2 g/head and 1 g/head, respectively. However 14 days after administering COWP, fecal worm egg counts were reduced by approximately 50% in goats receiving 1 g/22 lb live weight or 2 g/head and remained essentially the same in goats receiving 1 g/head. Because there was no control treatment, we were unable to estimate how much worm egg counts might have increased if animals had received no COWP.

No does were chemically dewormed during the study although FAMACHA scores remained high (score of 4) on several does. Protocol generally indicates deworming at a FAMACHA score of 4 but the farmer was resistant to this and observed animals closely every day. Pasture management was excellent. Goats were moved rapidly through pastures to prevent autoinfection and the pastures had not been grazed by goats since 2012. Instead they were harvested for hay or grazed by cattle. Throughout the study, no does scored a “5” indicating the need for immediate deworming. The high levels of barber pole worm infection observed at the beginning of the study were attributed to a “barnyard effect” from the forage filled barnyards the goats had access to prior to going out to pasture in mid-May. The goats were also exposed to these barnyards during the study but grazing was discouraged by keeping them mowed extremely short and providing hay in them at all times.

The cheese maker was asked to observe whether the time to set curd and/or the curd consistency appeared abnormal for the four types of cheeses made during the week following COWP administration. She observed no changes.

Copper levels in milk within each sampling day were not significantly different among COWP levels. Changes in copper concentration from Day O to Day 42 were not significant. However, in a paired t test copper concentrations increased significantly (P < 0.0016) from 0.105 ppm ± 0.019 to 0.171 ppm ± 0.019 from Day 0 to Day 14 for 1 g/22 lb live weight but not for 2 g/head (P < 0.06) or 1 g/head (P < 0.07). Notably, even the highest levels of milk copper were below maximum allowable levels. Plasma AST concentrations on Day 42 were 118 ppm ± 6.9, 121 ppm ± 7.2 and 113 ppm ± 7.2 for 1 g/22 lb live weight, 2 g/head and 1 g/head, respectively, and did not differ significantly among levels of COWP. Copper toxicity elicits AST enzyme activity values of > 300 ppm. Only two does had AST values greater than 200 (203 and 221 ppm respectively).

In this study, COWP dosages of 2 g/head caused reductions in fecal egg counts similar to dosages of 1 g/22 lb live weight in lactating dairy does but only used 25% (large does) to 50% (small does) as much COWP after accounting for the live weight of the does.

Lamb and kid grazing study. Weaned lambs were assigned randomly within each of three farms to Control, low COWP (LCOWP), or high COWP (HCOWP). Pooled fecal samples were taken from lambs and kids at weaning age prior to return to pasture to determine the distribution of worm species and extent of infection at weaning time. Based upon the extent of infection, animals in the Control group were given either no treatment or dewormed with a chemical anthelmintic known to be effective on each farm. Animals in the LCOWP group were given 0.5 g COWP. Animals in the HCOWP group were given 1 g COWP. Individual fecal samples and FAMACHA scores were obtained on days 0, 14, and 28 after administration of the COWP. Fecal egg counts specific for H. contortus were measured and the lambs were weighed on days 0 and 28. Fecal egg counts were transformed to natural log values to normalize them for analysis of variance with the effects of COWP, day of sampling, and the interaction in the statistical model. On one farm there was an interaction (P < 0.10) for fecal egg counts between level of COWP treatment and date of fecal sampling, indicating that the effect of COWP depended upon sampling day. Fecal egg counts in Control lambs (not given COWP) increased dramatically from 185 eggs/g on day 0 to 1920 eggs/g on day 28. Fecal egg counts from lambs given either 0.5 g COWP or 1 g COWP actually decreased from 67 eggs/g on day 0 to 14 eggs/g on day 14, with only a modest increase at day 28 to level of 488 eggs/g, much lower than would dictate deworming. But COWP had no effect on any response variables for the other two farms. Excellent rotational pasture management was practiced on one of these farms and resulted in low fecal egg counts that declined form 446 eggs/g on day 0 to 187 eggs/g on day 28. Although fecal egg counts increased from day 0 to day 28 on the other farm, there was no effect of COWP level.

2014

Studies focused on determining whether the timing of COWP administration in relationship to weaning was an important determinant of the effectiveness of COWP in recently weaned lambs. At two sheep farms using primarily Dorset genetics, COWP was given two weeks prior to weaning and two weeks post weaning to young stock within the same lamb crop at three dosage levels (0, 0.5 g, or 1 g) for barber pole worm control in the 6 weeks following weaning. The same levels of COWP dosing were also evaluated in self-weaning lambs and Boer goat kids at two farms. On one farm the self-weaning lambs were further divided and compared for Clun Forest versus Romney genetics. The effect of three levels of COWP dosing (0, 1 g, or 2 g) and of genetics (Clun Forest versus Romney) on worm infection was also compared on the lactating dams. Pasture management practices and mineral composition of pasture and supplementary feed that might influence the effectiveness of COWP treatment were also recorded. Data analyses indicated that COWP dosing was effective at reducing barber pole worm infections at one sheep farm both pre- and post-weaning but there was no effect on the other three farms.

2015

In 2014, COWP dosing to control barber pole worm did not appear very effective in flocks and herds where kids and lambs were “self-weaned” and supplemented with concentrates as compared to flocks where lambs received little concentrate and were dosed with COWP 2 weeks prior to weaning. The 2015 COWP studies focused on  the effect of COWP dosing 2 weeks pre-weaning on 1) Boer goat kids weaned at ~10 weeks of age and provided with some concentrate pre and post weaning, and 2) Dorset X lambs under three different nutritional regimens: conventional pastures (CP), birdsfoot trefoil pastures (BFT), or hay/grain (HG).

Kid studyEight kids each were assigned to the following treatments: Control (no COWP), 0.5 g/head COWP, 1.0 g/head COWP, and 1.5 g COWP/head.  Dosing with COWP occurred 2 weeks pre-weaning.  Fecal samples and FAMACHA scores were taken every 2 weeks from 2 weeks pre-weaning until 4 weeks post-weaning. Average increase in barber pole worm egg counts was highest for the Control treatment (+4262 epg), lowest for the 1.5 g COWP treatment (+2373) and intermediate for 0.5 g COWP (+3215 epg) and 1.0 g COWP (+3048 epg) over the 6-week study but must await further analyses to test if the differences were significant. Future studies in goat kids, but not lambs, may might include dosages of 2.0 g COWP per head to determine if this higher dosage results in further improvements in barber pole worm control.

Lamb study Eight lambs each were assigned to the following treatments: BFT + COWP, BFT alone, CP + COWP, CP alone, or HG + COWP. Fecal samples and FAMACHA scores were taken every two weeks from 2 weeks pre-weaning until 8 weeks post weaning.  Lambs were weighed 2 weeks pre-weaning, at weaning and 8 weeks post weaning. All lambs that received COWP 2 weeks pre-weaning appeared to have lower round worm egg counts and more desirable FAMACHA scores for eight weeks post weaning as compared to the group of lambs that were grazed on BFT alone and especially the group of lambs that were grazed on CP alone. These changes in roundworm egg counts resulted almost entirely from changes in the barber pole worm egg population. We were excited by a dip in worm egg counts for the two BFT groups at 6weeks post-weaning although it appears to have been temporary.  In addition, no lambs on the BFT pasture alone, the BFT + COWP or the CP + COWP treatments had to be dewormed over the 70-day experiment.  In contrast, 2 lambs required deworming on the HG + COWP treatment, and 4 of 8 lambs grazed on the CP alone had to be dewormed based on severe anemia and weakness. Daily weight gains over the 70 d study averaged 0.3 lb, 0.25 lb, 0.22 lb, 0.18 lb, and 0.16 lb for BFT + COWP, HG + COWP, BFT, CP + COWP and CP treatments, respectively. Further analyses of our COWP and BFT studies will 1) provide better clues as to why the efficacy of COWP varies among farms and 2) help determine whether the use of BFT pastures during post-weaning stress is justified despite difficulties in establishing heavy stands of BFT and its relatively slow regrowth compared to conventional clover/grass pastures.

Funding

This work was supported by a joint research and extension program funded by the Cornell University Agricultural Experiment Station (Hatch funds) and Cornell Cooperative Extension (Smith Lever funds) received from the National Institutes for Food and Agriculture (NIFA,) U.S. Department of Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture. In addition, we are grateful for funding from:

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Michael L. Thonney, Professor
Director, Cornell Sheep Program and Graduate Field of Animal Science
114 Morrison Hall
Cornell University
Ithaca, NY 14853-4801
mlt2@cornell.edu
607-592-2541

Dan L. Brown, Associate Professor
Nutritional Toxicologist
320 Morrison Hall
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607-255-4027
dlb20@cornell.edu

tatiana L. Stanton, Extension Associate
Goat Specialist
114 Morrison Hall
Cornell University
Ithaca, NY 14853-4801
tls7@cornell.edu 
607-254-6024

Niko Kochendoerfer, Graduate Assistant
110 Morrison Hall
Cornell University
Ithaca, NY 14853-4801
nk584@cornell.edu


Major revision: October 2015
Please contact Mike Thonney at mlt2@cornell.edu if you can't find something from the previous version.
Copyright © 2015 Michael L. Thonney

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