Final report for LNE14-337
Project Information
This project provided several take-home messages that proved to be beneficial for effective management of Haemonchus contortus (HC) by sheep producers in the Northeast region. We validated several methods to reduce the exposure of sheep to infective larvae of HC during the grazing season; 1) delay turn-out of sheep onto Spring pastures until after vigorous grass growth starts in early June (we found, in a controlled study, that adult ewes placed on a static pasture (i.e., no rotational grazing) in central Maine in early June had significantly lower parasite egg counts, lower FAMACHA scores, and were dewormed fewer times than ewes placed on a similar pasture in mid-May. This positive effect also extended to lambs on these ewes, with lower egg counts, less anemia and faster growth rates in lambs within the group that delayed grazing until June). 2) Monitor fecal egg counts of grazing ewes in September, and treat the 50% of the flock containing the highest HC counts using an effective chemical anthelmintic. Treated sheep had virtually no "Spring Rise" during the following Spring lambing season, and fecal egg counts in this flock never increased to a level where any animals required deworming during the following grazing season. 3) Using producer survey data, we attempted to identify sheep management practices that were associated with low fecal egg counts of HC in grazing sheep on commercial farms (this survey differed from similar surveys that we could identify because we monitored both total strongyle egg counts and HC-specific fecal egg counts using a lectin-based fluorescent diagnostic technique). We found two factors that were associated with lower HC egg counts during the early, mid and late grazing season - implementing a rotational grazing strategy, and maintaining density of adult sheep on pasture at less than 4 animals per acre.
During the second and third years of the grant, we worked with 25 farms to intensively monitor fecal egg counts of HC during Spring Rise, as we found that the level of eggs deposited during this period was closely associated with morbidity / mortality due to HC anemia throughout the subsequent grazing season. When we found farms with high HC counts, we recommended that producers follow up with a chemical dewormer treatment. Following each deworming, we asked producers to submit a fecal sample taken at the time of treatment, and a second fecal sample from each dewormed animal at ten days post-treatment. We used these samples to calculate a Fecal Egg Count Reduction percentage for the chemical dewormer used on each farm. We found that virtually all of the farms (22/25) had significant parasite resistance to the dewormer used. This resulted in additional egg count reduction tests using an alternate dewormer recommended by Dr. Weber. We managed to identify an effective dewormer on all of these farms by mid-June of that year. Our intensive Spring egg count monitoring, plus the use of effective dewormers by these farmers, resulted in significantly lower parasite counts and lower use of dewormers throughout the 2016 grazing season on these farms when compared to the same farms during the 2015 grazing season.
Based on our combined results, we now recommend that producers concentrate their parasite monitoring in the Spring, and complete an annual Fecal Egg Count Reduction Test prior to turning out sheep on pasture. We also recommend that sheep not be placed on summer pastures until at least 4 inches of forage growth is present, generally in early June. We recommended an aggressive rotational grazing system with a density of adult sheep of less than 4 animal per acre of total pasture used in the system.
We completed a cold-tolerance study of HC in 2016, and we found that parasites originating from sheep living in a northern climate were more tolerant of cold conditions than parasites from sheep on farms in the Deep South (Louisiana). Maine-sourced L3 larvae survived nearly 10 degrees C colder conditions when cooled slowly and held at the temperature for 36 to 48 hours. These results are consistent with our hypothesis that H. contortus larvae are becoming increasingly competent to survive winter on pastures in northern climates, and indicate that we may need to adapt our winter management strategies in northern New England to accommodate increased overwintering of this parasite.
We presented basic parasitology information and data generated during this project at 21 producer events during the four years of the project. Overall, we reached >400 producers during presentations / Q & A sessions, and taught 110 producers to use microscopy to measure fecal egg counts in their sheep. We processed over 7000 manure samples (from 313 commercial farms in northern New England, and from samples taken from the University of Maine sheep flock during research studies). Dr. Weber personally consulted with 250 farmers who had questions related to formulating an effective management plan in response to egg count data that we sent to their farms. We feel that the activities of this grant greatly increased the competence of sheep producers in our region in parasite management
One hundred NNE sheep and goat producers adopt more effective parasite management strategies, including routine monitoring of Haemonchus levels in their sheep through FAMACHA and fecal egg counts (completed).
Sixty producers will adopt at least three of the following cold weather management techniques to reduce or eliminate the shedding of Haemonchus ova on winter and spring pastures: 1. Winter dewormer treatment; 2. Hasten Spring rise through earlier lambing or increased photoperiod; 3. graze weaned lambs separate from dams on 'clean' pastures; 4. Use appropriate pasture stocking rates and practice rotational grazing; 5. reduce egg shedding on early spring pastures through the use of a 'mud season' paddock.
These management changes will positively affect the productivity of 2000 sheep and goats on 1000 acres of pasture, resulting in additional profits of $200 per year in the northern New England region.
Haemonchiasis is one of the most economically important diseases of small ruminant farmers in the United States. In the southern U.S., Haemonchus contortus has become a limiting factor in the production of sheep and goats on pasture. Management of Haemonchus on Southern pastures is hindered by the certainty that animals will rapidly become reinfected after treatment, since the infective stage of Haemonchus persists on pastures from one grazing season to the next.
Historically, northern New England winters have been considered too cold for the survival of Haemonchus on pasture, so years-long infestations should be impossible, at least in theory. However, Haemonchus has adapted to northern climates by undergoing a winter hypobiosis, where larval stages hibernate within adults until conditions become suitable for re-infestation of pastures. Consequently, producers in northern New England are now experiencing long-term infestations of Haemonchus. A 2012 survey of 20 Maine sheep and goat farms diagnosed Haemonchus as the dominant parasite, found in fecal samples on over 90% of tested farms. Estimates of economic losses from Haemonchiasis are not available from northern New England, but an Australian study associated Haemonchus infections with 20% higher mortality, 39% lower weight gain, and 16% lower wool growth. When this production loss, conservatively estimated at 20%, is extrapolated to the 1800 northern New England farms and their 32000 sheep and 17000 goats with a total value of $15 million, (2010 NASS survey) parasitism-related losses in this region could exceed $2 million per year.
New England farmers have been very active in Cooperative Extension and Experiment Station initiatives related to sheep and goat diseases, and their input demonstrates their growing concern about the impact of internal parasitism. Data from a 2008 Integrated Pest Management Survey of Maine sheep and goat producers listed internal parasitism (30%) as the most important disease problem on their farms. In a 2012 UMaine survey, participants were asked to describe how parasitism affected their operation (representative answers follow): "HUGE! hardest part of organic management. Ewe replacement lambs have the worst time during first year." "Parasites do decrease growth rates which is challenging and causes worry for does who lose condition quickly up to weaning."
Clearly, our producers are experiencing a significant Haemonchus problem that is impacting their ability to raise sheep or goats profitably on pasture, and would benefit from effective, region-specific management strategies that reduce morbidity / mortality in their sheep and goats from HC during the grazing season.
Cooperators
Research
Winter treatment of small ruminants with effective anthelmintics or increased winter
photoperiod will eliminate 100% of arrested abomasal larvae before the start of the following grazing season.
Performance Target 1) Winter dewormer treatment; University of Maine Icelandic ewes (n=10 ewes per group) were either treated in mid-September of 2016 with an effective anthelmintic (levamisole; n=8 ewes), or were not treated, . All ewes were bred in November, and fecal egg counts and percentage Haemonchus ova were enumerated weekly throughout the winter and through Spring Rise. Ewes and their lambs were then allowed to graze from May through October of the following year, and weekly egg counts were continued through the grazing season.
Performance Target 2) Hasten Spring rise through earlier lambing or increased photoperiod; After encountering difficulties with maintaining a consistent artificially decreased photoperiod in our research flock, we decided instead to mimic the effect of reduced photoperiod by treating ewes during mid-summer with oral melatonin. Two groups of ten Icelandic ewes (one control and one treated) at the University of Maine farm were dosed with 2000 L3 larvae of Haemonchus contortus during early June 2017. Control ewes were maintained on pasture, and were given about 0.5 pounds per day of grain-based concentrate 0.25 pounds each at 8 AM and 5 PM. Treated ewes were also grazed and given grain, but the grain was supplemented with melatonin at the rate of 10 mg per day per ewe. Melatonin treatment was continued until mid-July of 2017. Parasite egg counts and FAMACHA scores were measured weekly on all ewes, and blood samples (taken at ten AM) were collected bi-weekly for measurement of serum melatonin.
Performance Target 3) Graze weaned lambs separate from dams on ‘clean’ pastures; This objective was not completed due to insufficient space available for separate rotational grazing of ewes and lambs on our research farm. Instead, we used our resources to address a parasite treatment failure issue that we had documented during our routine parasite load testing on our commercial farms (follows): Intensive Spring monitoring of HC egg counts and dewormer effectiveness: In 2017, we completed data collection for our on-farm comparisons of parasite loads and management efficacy during the grazing season, with over 220 ME, NH, and VT producers participating. We initiated a new, more intensive monitoring scheme for regional producers, with 25 farms participating in intensive, individual monitoring of post-lambing ewes to detect and treat animals with large post-parturient increases in Haemonchus contortus egg counts during early Spring. Following initial testing of individual ewes, producers were instructed to treat heavily parasitized animals with a chemical dewormer. We followed up this treatment with a second round of parasite diagnostics ten days after dewormer treatment to identify whether the dewormers were decreasing egg counts in the treated ewes. If the treatments were ineffective, Dr. Weber worked with individual farmers to choose alternative dewormers that were still effective.
Performance Target 4) Utilize appropriate pasture stocking rates and practice rotational grazing; We used a producer-based field trial to identify whether a relationship existed among stocking rate, presence / absence of a rotational grazing plan, and fecal egg counts through the grazing season. At the beginning of the 2015 and 2016 grazing seasons, producers completed a survey that provided us with data regarding 1) the number of ewes and lambs grazing on each farm, 2) the number of fenced acres of pasture used on the farm, and 3) the grazing management plan used on the farm (static grazing, rotational grazing of ewes with lambs, or rotational grazing of ewes separate from lambs). Animals were placed on pasture in mid- May, and pooled fecal egg counts were calculated in early June, Mid-July and late August. The relationship between stocking rate, presence / absence of a rotational grazing plan, and fecal egg counts was then measured using regression techniques.
Performance Target 5) Reduce egg shedding on early spring pastures through the use of a ‘mud season’ paddock: In Spring 2015, two groups of Icelandic ewes plus their newborn lambs were randomly allocated to two groups - One group where grazing started on May 15, and another group where grazing started one month later., and the ewes were maintained prior to grazing on bedded packs with no access to grazing. In the later group, ewes were fed free-choice grass hay and less than a pound of concentrate per day until turnout onto pasture. Fecal egg counts, percentage HC ova / total strongyles, and FAMACHA scores were taken at weekly intervals from April through the end of the grazing season (late October). Once placed on pasture, ewes and their lambs had access to a static (non-rotationally grazed) pasture, and were stocked at a rate of 5 ewes per acre. Grazing ewes also had continuous access to first-cut grass hay. Ewes and lambs were dewormed with an effective dewormer (oral levamisole) whenever their HC-specific Fecal Egg Count exceeded 2000 eggs per gram, or when their FAMACHA score > 3 for two consecutive weeks.
One aspect of this project was to identify the effectiveness of dewormers that were in use on the participating farms. Our experimental design was to complete individual fecal egg counts (with HC enumeration) on all adult ewes on each farm, and identify the 50% of ewes with the highest HC counts for deworming. A sample of manure was collected from each treated ewe at the time of deworming, and again at ten days following deworming, to determine whether the treatment reduced HC egg counts.
Other projects arising from the grant-related research: We completed a Haemonchus contortus cold-tolerance study in 2016. Third-stage larvae were suspended in various buffers and were exposed to controlled temperatures for variable amounts of time using a programmable embryo freezing machine. We found that these larvae were extremely tolerant to short-term (<12 hours) cold temperatures, and that no mortality occurred until cold exposures exceeded 36 hours, so subsequent studies exposed larvae to temperatures ranging from 0 degrees C to -25 degrees C for 36 hour periods. Viability of treated larvae was assessed by ensuring their movement through a 20 micron screen after being warmed back to room temperature. We found that parasites originating from sheep living in a northern climate were more tolerant of cold conditions than parasites from sheep on farms in the Deep South (Louisiana). These results are consistent with our hypothesis that H. contortus larvae are becoming increasingly competent to survive winter on pastures in northern climates, and indicate that we may need to adapt our winter management strategies in northern New England to accommodate increased overwintering of this parasite.
Performance Target 1) Winter dewormer treatment; Ewes that had been dewormer during the previous Fall had significantly lower fecal egg counts during the subsequent Spring Rise, with no animals requiring dewormer treatment prior to the start of grazing. Fall-dewormed ewes continued to show almost non-detectable parasite burdens during the entire grazing season when placed into a rotational grazing system with pasture changes at weekly intervals throughout the summer and fall. In contrast, ewes that ere not fall-dewormed all required deworming during Spring Rise and at least once during the grazing season due to fecal egg counts above our upper threshold of 2000 eggs per gram.
Performance Target 2) Hasten Spring rise through earlier lambing or increased photoperiod (changed to Effect of melatonin treatment on HC larval development): A method for ELISA determination of serum melatonin in sheep serum was validated in our lab, and the blood melatonin concentrations in our treated animals 4 to 5 hours post-treatment were at the high end of the normal range reported for melatonin in the literature, demonstrating that the supplemented melatonin had entered the bloodstream at physiological concentrations. We measured significantly higher melatonin levels in the melatonin-treated ewes than in the control ewes. However, the L3 dosing did not result in a change in the fecal egg count of Haemonchus contortus in either group of sheep, so we did not have a measurable population of HC larvae in our treated ewes, and hence could not make objective comparisons of the effect of melatonin on HC egg production. This result was unexpected, and may have been due to improper handling of the larvae during their culture period, since HC egg counts in the control (vehicle-only treatment) ewes did not rise significantly in the weeks following bolus administration of 2000 L3 HC larvae to each ewe. Conclusion: Melatonin concentrations in grazing ewes during mid-summer were manipulated in this study through oral dosing of melatonin within a small twice-daily feeding of a pelletized supplement, and treated ewes likely experienced blood melatonin concentrations similar to what is naturally found in the fall at latitudes in northern New England. However, we were unable to test our hypothesis that exposure of HC L3 larvae to winter concentrations of melatonin would stimulate an artificial hypobiosis where larvae would fail to mature in to egg-laying adults.
Performance Target 3) Intensive Spring monitoring of HC egg counts and dewormer effectiveness: In 2017, we completed data collection for our on-farm comparisons of parasite loads and management efficacy during the grazing season, with over 220 ME, NH, and VT producers participating. We initiated a new, more intensive monitoring scheme for regional producers, with 25 farms participating in intensive, individual monitoring of post-lambing ewes to detect and treat animals with large post-parturient increases in Haemonchus contortus egg counts during early Spring.
One aspect of this project was to identify the effectiveness of dewormers that were in use on the participating farms. We found that nearly all of the chemical dewormers used on these farms did not effectively reduce parasite loads, and recommended that producers switch to other, more effective drugs. The intensive spring monitoring, plus the use of effective dewormers by these farmers resulted in significantly lower parasite counts and lower use of dewormers throughout the subsequent grazing season on these farms when compared to the previous grazing season.
Performance Target 4) Utilize appropriate pasture stocking rates and practice rotational grazing; Based on data from over 150 sheep and goat farms, we found that peak total egg counts and Haemonchus contortus egg counts occurred during the month of July. We also identified that farms that practiced either rotational grazing or maintained a stocking density lower than 4 ewes per acre were associated with <50% reduction in parasites. Farms that used rotational grazing and maintained low stocking densities had the lowest parasite counts in the study, with fecal egg counts remaining below threshold levels for deworming throughout the grazing season on all of these farms.
Performance Target 5) Reduce egg shedding on early spring pastures through the use of a ‘mud season’ paddock: We found that adult ewes placed on a static pasture (i.e., no rotational grazing) in central Maine in early June had significantly lower parasite egg counts, lower FAMACHA scores, and were dewormed fewer times and later in the grazing season than ewes placed on a similar pasture in mid-May. This positive effect also extended to lambs on these ewes, with lower egg counts, less anemia and faster growth rates in lambs within the group that delayed grazing until June.
Intensive Spring monitoring of HC egg counts and dewormer effectiveness: In 2017, we completed data collection for our on-farm comparisons of parasite loads and management practices during the grazing season, with over 200 ME, NH, and VT producers participating. We initiated a new, more intensive monitoring scheme for regional producers, with 30 of these farms participating in intensive, individual monitoring of post-lambing ewes to detect and treat animals with large post-parturient increases in Haemonchus contortus egg counts during early Spring.
One aspect of this project was to identify the effectiveness of dewormers that were in use on the participating farms. We found that nearly all of the chemical dewormers used on these farms did not effectively reduce parasite loads, and recommended that producers switch to other, more effective drugs. The intensive spring monitoring, plus the use of effective dewormers by these farmers resulted in significantly lower parasite counts and lower use of dewormers throughout the subsequent grazing season on these farms when compared to the previous grazing season.
Other results from the project: Our Haemonchus contortus cold-tolerance study was completed in 2016, and we found that parasites originating from sheep living in a northern climate were more tolerant of cold conditions than parasites from sheep on farms in the Deep South (Louisiana). These results are consistent with our hypothesis that H. contortus larvae are becoming increasingly competent to survive winter on pastures in northern climates, and indicate that we may need to adapt our winter management strategies in northern New England to accommodate increased overwintering of this parasite.
This project provided several take-home messages that proved to be beneficial for effective management of Haemonchus contortus (HC) by sheep producers in the Northeast region. We validated several methods to reduce the exposure of sheep to infective larvae of HC during the grazing season; 1) delay turn-out of sheep onto Spring pastures until after vigorous grass growth starts in early June (we found, in a controlled study, that adult ewes placed on a static pasture (i.e., no rotational grazing) in central Maine in early June had significantly lower parasite egg counts, lower FAMACHA scores, and were dewormed fewer times than ewes placed on a similar pasture in mid-May. This positive effect also extended to lambs on these ewes, with lower egg counts, less anemia and faster growth rates in lambs within the group that delayed grazing until June). 2) Monitor fecal egg counts of grazing ewes in September, and treat the 50% of the flock containing the highest HC counts using an effective chemical anthelmintic (Fall-treated sheep had virtually no “Spring Rise” during the following Spring lambing season, and fecal egg counts in this flock never reached a level where any animals required deworming during the following grazing season). 3) Using producer survey data, we attempted to identify sheep management practices that were associated with low fecal egg counts of HC in grazing sheep on commercial farms (this survey differed from all other surveys of this type that we could identify because we monitored both total strongyle egg counts and HC-specific fecal egg counts). We found two factors that were associated with low HC egg counts during the early, mid and late grazing season – implementing a rotational grazing strategy, and maintaining density of adult sheep on pasture at less than 4 animals per acre.
Education
A major emphasis of this project was the education of producers to measure and effectively manage parasite populations on their own farms. We achieved this objective through several methods. First, we conducted multiple producer education seminars throughout Northern New England to teach the basic principles of parasite management. We also taught specific skills to producers, including the use of a microscope to identify and enumerate parasite species in manure samples from their farm, and the use of the FAMACHA technique to identify animals with anemia that might be caused by a Haemonchus contortus infestation.
In addition to the formal training coursework, we worked with over 250 producers to identify and solve parasite-related problems on their farms. We set up parasite diagnostics prior to each grazing season, where producers would send us individual manure samples from all adult animals on their farm, and we would identify potential health problems related to parasites found in the samples. Many of the parasite-related problems detected on these farms during the screenings were discussed with the producers on the phone or through email communications. For example, we found that the dewormers used by many of our producers were no longer effective in reducing their parasite populations due to the development of genetic resistance. Once these deficiencies were identified, we would recommend another class of dewormer and work with the producer to test its efficacy on their animals. As a result, most of the potential parasite-related health problems in these producer flocks were "solved" prior to the high risk period for Haemonchus (i.e, the mid-summer grazing season), and farmers enjoyed greater production due to our involvement..
Milestones
Producers learn how to measure the extent of parasitism in their individual sheep / goats through FAMACHA scoring or microscopic evaluation of fecal egg counts.
100
3
142
2
May 31, 2018
Completed
September 30, 2018
In late 2015 we completed monitoring of pooled fecal egg counts from pooled samples during three critical periods during the early-, mid-, and late-season grazing. Over 120 farms submitted data for an entire grazing season and also completed a survey of their farm metrics and management practices.
We provided hundreds of veterinary consults to producers based on farm-specific data. Many of these farms decreased their Haemonchus counts between the first and second year of monitoring. We changed our field study emphasis in 2016 to more intensive monitoring and treatment of a small subset of farms that were willing to collect individual manure samples from each of their animals at multiple times during early spring, a period that is critical for parasite success in northern New England.
Ten farms from Maine, New Hampshire and Vermont participated in this study. Our plan was to identify, at the time of spring lambing, ewes that had carried heavy burdens of Haemonchus larvae through the winter and were at risk of anemia as these larvae matured into feeding adults. Furthermore, we wanted to identify heavy shedders of Haemonchus ova during the spring, since these ova were likely to develop into infective larvae during early June and increase exposure of ewes and lambs to Haemonchus during the upcoming grazing season.Highly parasitized ewes were identified and communicated to producers, and then were treated with a chemical anthelmintic. Manure samples were again assayed for parasites at 10 to 14 days post-treatment to assess the efficacy of treatments.
We found that many of the participating farms, plus about ten farms that were evaluated for dewormer effectiveness using the Fecal Egg Count Reduction Test (FECRT), did not achieve effective reductions in parasite burdens after the initial anthelmintic treatment. For farms with anthelmintic failure, we reviewed their history of dewormer use and made recommendations on alternative chemical dewormers that might be more effective on their farms. We then followed up with an additional FECRT to ensure that animals were carrying low burdens of parasites, including Haemonchus contortus, onto fields at the beginning of the 2016 grazing season.
A preliminary comparison of fecal egg count data from 2015 (pre-intensive monitoring) to to 2016 (post-monitoring and consultation) showed decreased parasite counts in 2016. In 2016 we completed development work on a quantitative in vitro assay to measure the cold tolerance of the L3 stage of Haemonchus contortus that persists on pastures and infects grazing sheep. We then conducted testing of prolonged (3 to 6 days of exposure) of L3 larvae obtained from farms in Maine, Virginia, Arkansas and Louisiana. We found that the Maine-sourced L3's were tolerant of cold exposure down to at least 10 degrees C. Parasites from Arkansas and Virginia were not significantly different from the Maine L3's in cold tolerance, but the Louisiana-based L3's were killed by significantly warmer temperatures ranging between 20 and 25 degrees C. While these are preliminary results, they indicate that there may be an evolutionary adaptation of the infective L3 stage of Haemonchus to cold that would increase its overwinter survival on pastures in northern climates.
During the winter of 2015 / 2016, we performed a preliminary study, using our university flock, that compared the effectiveness of preventative anthelmintic treatment at different times during the non-grazing season. We found that fall deworming of adult ewes almost completely eliminated their subsequent spring rise. The fall 2015-treated animals were then placed on an aggressive rotational grazing system during 2016, and required no dewormer treatments. In contrast, all of the animals that did not receive a fall deworming experienced spring rise-associated parasitism and anemia that required one or more dewormer treatments, and that likely resulted in significant contamination of their paddocks / fields with Haemonchus ova during the spring of 2016. We are currently repeating this study using larger numbers of animals, and will continue to collect data through the grazing season of 2017.
During 2016, we presented basic parasitology information and data generated during the first years of this project to several producer groups in 2016. Overall, we reached >200 producers during four separate events. We also taught 40 producers to use microscopy to measure fecal egg counts in their sheep. All of these presentations and workshops occurred in northern New England.
Outcomes
Several potentially valuable outcomes have resulted from our 2016 work. First, we implemented a pre-grazing season monitoring and treatment strategy on ten northern New England farms that seemed to reduce Haemonchus contortus parasitism in sheep during the subsequent grazing season. We feel that an intensive period of parasite monitoring and targeted treatment during the immediate post-lambing period may be an effective tool for decreasing parasite burdens in sheep during the subsequent grazing season. Our detection of parasite resistance to ivermectin-type dewormers in multiple northern New England farms built on evidence from multiple published reports that Haemonchus contortus in U.S. sheep is becoming resistant to multiple chemical classes of dewormers. Preliminary results from 2015 / 2016 indicated that fall-based identification and treatment of a sub-population of ewes that are overwintering large burdens of Haemonchus larvae may result in reduced ewe anemia at the time of lambing, when ewes are already at high levels of nutritional stress. Reduction of egg-laying adults in the spring would also decrease spring contamination of pastures. Use of selective fall deworming, combined with delayed entry of sheep onto northern pastures until after "mud season" (2015 results) and effective rotational grazing, appear to reduce the impact of Haemonchus contortus on grazing sheep to levels that do not require interventional dewormer treatment of anemic animals during the relatively short grazing seasons in northern climates.
A cornerstone of effective parasite or pathogen management should be to reduce exposure of target animals to the infectious agent rather than treating them after they become ill. The U.S. sheep industry in northern tier states would certainly benefit from a reduction in the "salvage" treatment of heavily parasitized, anemic sheep and lambs that might result from implementation of our findings. Preliminary information from our in vitro cold tolerance study indicates that Haemonchus contortus may be evolving an increased tolerance of winter cold. if confirmed, this may translate into higher winter survival of infective larval stages on northern New England pastures. Higher overwinter survival on pasture may eventually reduce the effectiveness of winter treatments / management changes that target hypobiotic stages that overwinter in the sheep gut.
Principle Investigators meet to discuss implementation of grant components. A steering Committee is formed from leaders in the sheep and goat industries in northern New England, and holds its first annual meeting in fall 2014.
5
5
November 14, 2015
Completed
September 01, 2015
The authors of this grant proposal met during a series of phone and Skype meetings to formulate a plan for recruitment of producers and scheduling of training events. The research projects planned for this project were discussed and updated.
Producer seminars (basic parasitology 101) are held in ME, VT and NH. 60 to 70 producers attend each event. Materials form these seminars are recorded and made available on-line through podcasts and webinars.
60
400
1
August 28, 2018
Completed
June 13, 2018
Twenty-one producer training events were organized by regional extension professionals in Maine, New Hampshire and Vermont. Seminars covered basic parasitology, plus any new information that we had produced from the research activities of the grant. Farmers in 11 of these events worked with sheep and goat manure samples to enumerate parasite egg counts using standardized microscopic techniques. Farmers attending the earlier meetings were successfully recruited to participate in field studies during the later years of the grant.
Parasite species are identified on 100 farms throughout NNE. Producers receive farm-specific information, then are taught effective management techniques based on the parasite species present in their animals. These participants are recruited for further studies.
100
200
September 30, 2017
Completed
July 31, 2018
During separate studies in 2014 through 2017, >300 sheep and goat farms participated in on-farm research by submitting either pooled or individual fecal samples from their animals for egg count analysis at pre-determined times during the Spring and the grazing season. We used these samples, along with responses to survey questions about each farm's management practices, to identify practices and farm attributes that were effective in reducing parasite egg shedding during the grazing season. We also communicated with most of these farmers during the period after our parasite egg count data was sent to them. Most of these communications were related to developing an effective change in management strategy that would reduce HC infestations on their farms to below pathogenic levels. Many of the farms that participated in our earlier studies were recruited to participate in later studies that concentrated on the management of Spring Rise, and on the identification of effective chemical anthelmintics for their specific farm.
Annual seminar is held in ME, VT and NH. Topics include wet labs to train producers how to identify parasites through fecal egg counts and Haemonchus infestations through the FAMACHA technique.
50
156
1
September 30, 2017
Completed
May 31, 2018
A standardized one-day fecal egg count training course was developed, and was used to train producers during 11 wet-labs held in Maine and New Hampshire. Producers were shown how to extract parasite eggs from their own animals' fecal samples, and to identify and enumerate parasites by species using fecal egg floatation, McMaster's slides, and light microscopy. Producers successfully analyzed multiple samples during each wet lab. Each session was ended by a question and answer session that stressed effective management of parasites using the fecal egg count. We also conducted FAMCAHA training during four of these day-long events, and discussed the use of FAMACHA and egg counts in the management of HC.
Regional producers learn about the Haemonchus eradication and winter kill projects. Discussions are held with producers to determine identify the parasite management strategies currently in use on their farms. Parasite management strategies currently in use on these farms are identified, and indices related to farm productivity during the 2015 grazing season are recorded.
50
200
January 31, 2018
Completed
November 30, 2018
As described in earlier milestones, producers participated in a variety of didactic and hands-on training opportunities during the grant period, and producers were introduced to several effective parasite management strategies. Producers also participated in research that combined multiple samplings of fecal egg counts on their grazing animals with surveys designed to identify key management practices that reduced fecal egg counts in grazing sheep and goats.
On-farm and controlled research results are communicated to producers throughout northern New England and nationally through Web-based media such as Land Grant Cooperative Extension sites and EExtension.
500
October 31, 2017
In Progress
The results of this project are currently being prepared for several peer-reviewed publications that will be submitted in 2019. We are also working with University of Maine Cooperative Extension to develop a series of fact sheets about parasite management in climates with a severe winter. We expect these to be available on-line in late 2019.
Project data are presented at national and regional conferences. Self-learning modules on parasite control are formed. Parasite burdens are monitored on farms that attempted eradication. A final set of regional parasite management conferences are held to to receive producer feedback.
400
2
October 31, 2018
Completed
November 30, 2018
Research results from this project have been presented at the American Association of Small Ruminant Practitioners, and at State continuing education conferences for veterinarians. We also presented data on parasite management to the National Dairy Goat Association, and to multiple regional and State organizations that support producers of sheep and goats in New England. A summary of results was presented to the NCERA-214 multi-State working group to improve sheep productivity during their annual meeting in 2017.
Belfast-microscopy-lab-March-2017 Management Strategies to Control Haemonchus contortus in Sheep
NE-SARE-microscopy-workshop-on-line-manual Virtual Microscopy Workshop for Sheep and Goat Producers
(or, how to count parasites under the microscope!!!)
MSBA newsletter article, spring-2014 Know your enemy! Control Haemonchus contortus
by manipulating its winter ecology
Milestone Activities and Participation Summary
Educational activities:
Participation Summary:
Learning Outcomes
We identified several areas where producers demonstrated an increased proficiency in the management of parasites on their farms. Many of them learned to diagnose their own parasite infestations through the use of microscopy and parasite egg identification and enumeration, and through the identification of anemia individual animals through FAMACHA scoring. We found that many of our most committed producers were able to intervene and reduce parasite damage before experiencing death or production losses. Currently, we are relying on email communications to identify changes in producer knowledge. During the last year of the grant (2018), we plan to survey producers who participated in our diagnostic outreach projects to quantitate changes in knowledge and proficiency.
Performance Target Outcomes
Target #1
100
These farmers will use more non-chemical means to effectively control their Haemonchus infestations during the grazing season, including rotational grazing, Spring-time determination of the severity of spring rise Spring-time determination of their current dewormer's efficacy, and use of dewormers based on individual fecal egg counts.
One hundred farms x an average farm size in Northern New England of about 20 sheep or goats = 2000 adult ewes plus about 3000 lambs per year.
These changes will result in an increase in the number of lambs that survive to either market or reproductive age.
122
These farmers used non-chemical means to effectively control their Haemonchus infestations during the grazing season, including rotational grazing, Spring-time determination of the severity of spring rise Spring-time determination of their current dewormer's efficacy, and use of dewormers based on individual fecal egg counts.
We estimate that over 4000 lambs on farms in Maine, New Hampshire and Vermont had reduced exposure to Haemonchus contortus parasitism during their first grazing season. This reduced exposure resulted in lower rates of lamb death, and probably increased weight gain for lambs destined for the meat market.
It is reasonable to expect that our farmers experienced a 10% increase in average weight gain and a change in parasitism-related death loss from 20% to 10%,. Based on the values, the measurable benefit would have been an extra 336 lambs that did not die during their first year.