Source: WEST VIRGINIA UNIVERSITY submitted to NRP
SUSTAINABLE SMALL RUMINANT PRODUCTION IN THE SOUTHEASTERN U.S.
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0232535
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
SCC-81
Project Start Date
Nov 1, 2012
Project End Date
Sep 30, 2017
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
WEST VIRGINIA UNIVERSITY
886 CHESTNUT RIDGE RD RM 202
MORGANTOWN,WV 26505-2742
Performing Department
Animal & Veterinary Science
Non Technical Summary
In January 2012, there was a 2% decline in sheep and lambs and a 5% decline in all goat inventory in the U.S. (NASS, 2012). Even though total inventory decreased from 2011 to 2012, some southern states have experienced large increases in sheep and goat numbers. For example, Virginia experienced an increase of 10% in total breeding sheep and lamb inventory and a 12% increase in meat and other goat inventories during the same period (NASS, 2012). Increased sheep and goat numbers in some states reflects a growing demand by ethnic populations and niche markets. However, the U.S. is still importing more lamb and goat meat than it is producing for domestic consumption. There is also a growing market for organic meat products (Green and Kremen, 2003). Both conventional and organic lamb and goat production in the southeastern U.S. is challenged because of the prevalence of gastrointestinal nematodes (GIN), particularly the blood-sucking Haemonchus contortus which has developed resistance to available dewormers (Howell et al., 2008; Crook et al., 2010)). Research to find new methods of GIN management is necessary. Priority areas include improved genetics, novel products or feedstuffs that act as anthelmintics, continued integration of the FAMACHA system (Kaplan et al. 2004) and a selective deworming program, and alternative forage systems. An abundance of forages in the southeast allows for organic and forage-fed systems for small ruminants. But low forage quality of warm season species during summer months limits growth and productivity of livestock. Although these forages are hardy, they often cannot meet nutritional needs during growth and lactation phases. Goats prefer browse species which have been grazed out of many pastures or were not available if goats were added to existing sheep or cattle operations. Forage-based production systems require appropriately adapted small ruminant germplasm. Traditional, high producing breed types may not necessarily be the breed resources best suited for the environmental and management conditions in the southeastern U.S., but rather small-framed breed types, such as hair sheep and landrace goat breeds may be a better fit. Although these breed types have slower growth rates, their production efficiency may be higher, and their leaner and smaller carcasses are well accepted by most ethnic markets (Wildeus, 1997). Research is needed to evaluate the production potential of various breed types and crosses under forage-based production systems. These research priorities, parasite control, forage resource management, and identification of appropriate breed resources, require coordinated efforts of multiple research institutions, each contributing their specific expertise towards the design of integrated systems.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3133610109070%
3133610111010%
3133610104010%
3133610108010%
Knowledge Area
313 - Internal Parasites in Animals;

Subject Of Investigation
3610 - Sheep, live animal;

Field Of Science
1040 - Molecular biology; 1090 - Immunology; 1110 - Parasitology; 1080 - Genetics;
Goals / Objectives
Develop integrated GIN control methods that decrease reliance on chemical dewormers through the use of selective deworming (FAMACHA system), better forage management and grazing options, and breed or animal selection for nematode resistance or resilience. Develop a forage-based feeding system for year-round grazing that meets nutritional requirements by evaluating performance of forage (legumes, grass, and browse) varieties and/or forage systems and animal performance. Evaluate the production potential of pure- and crossbred sheep and goat germplasm under forage-based production systems in the southeastern US. Disseminate research results and information to producers through station field days, workshops, and websites.
Project Methods
Integrated control methods will include the strategic use of anthelmintics, FAMACHA, copper oxide wire particles (COWP), condensed tannin containing forages, complete balanced rations, nematode-trapping fungi, vaccines and resistant breeds. The importance of evaluating these methods in various combinations is to achieve adequate control with minimal use of anthelmintics. Studies involving condensed tannin containing forages including the legume sericea lespedeza etc. will be conducted at all participating agencies to evaluate potential both as a forage (grazing schemes and fed fresh) and as processed (hay, pellets, cubes, extracts, etc.) products. Trials at WVU will measure specific immune responses of St. Croix sheep during a primary and challenge infection with H. contortus to elucidate mechanisms of immunity generated by sheep resistant to H. contortus infection. Ultimately, the results of these trials will lead to an integrated strategy for controlling worms.Cool-season and warm-season annual and perennial forages will be established, evaluated and compared to determine forage availability and quality, stocking rate, and animal performance during different stages of production by North Carolina State University and Kentucky State University for goat production systems, and by the USDA-ARS Grazinglands Research Laboratory, Reno, OK, for sheep production systems. At North Carolina State University, other thrusts will be the integration of fodder trees into grazing systems for goats and evaluating the performance and impact of grazing goats on soil nutrient cycling in legume-grass pasture systems. Co-grazing of cattle and meat goats on reclaimed coal-mined land to control invasive species such as broadleaf weeds and brushy and woody vegetation will be evaluated by Virginia Tech, as an environmentally friendly alternative to herbicide application or mechanical cutting. Fort Valley State College will use goats and sheep in browse-type vegetation management experiments for the removal of unwanted species or for the management of browse areas as a feed resource. Kudzu will be one of the invasive species under evaluation. Low-input establishment of Sericea lespedeza as a summer grazing/hay crop for small ruminants will be evaluated by Fort Valley State University, whereas Langston University will compare the efficacy of grazing Sericea lespedeza and Kobe lespedeza to help control gastrointestinal tract nematodes in goats. Three varieties of Sericea Lespedeza will be established at Kentucky State University to evaluate grazing preference and animal performance with varied levels of condensed tannins.Producer workshops, which teach the use of FAMACHA, fecal egg counts, and other integrated parasite control strategies will be taught throughout the region. Parasite control will continue to be an important educational focus in the region. Efforts are strongly supported by the work in the other objectives.

Progress 11/01/12 to 09/30/17

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Over the past five years we have been able to further elucidate immunological mechanisms resulting in greater parasite expulsion in St. Croix hair sheep. The culmunation of immune events resulting is greater host protection can lead to discovery of potential methods to make economically-relevant breeds of sheep more resistant to parasite infection. Many economically-relevant breeds of sheep lack parasite resistance. However we have found that incorporation of Texel breeding can reduce parasitism in crossbred progeny. Through a partnership with Virginia Tech we have been comparing the effect of Texel and Suffolk breeding on Katahdin ewes in efforts to improve carcass merit and parasite resistance. Our data has demonstrated that while there is no advantage in growth, Texel-Katahdin crossbred lambs are superior in terms of parasite resistance. Grazing high tannin forages have been shown to reduce parasitism in grazing small ruminants. The most popular specie is sericea lespedeza yet in some environments due to soil conditions SL does not grow well. In those environments trefoils tend to grow better. After planting a stand of high tannin trefoil we discovered that high tannin forgaes can be used as both a preventative and therapeutic.

Publications


    Progress 10/01/15 to 09/30/16

    Outputs
    Target Audience:Target audience for this project are small ruminant producers in the southeastern US and fellow scientists working in the area parasite immunology Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This porject has provided training opportunities for an MS student (Denzel Middleton) and training opporutnities for 3 PhD students (Jesica Jacobs, Brynnan Russ and Elizabeth Shepherd). A postdoctoral fellow also received traing through this project (Dr. Javer Garza) How have the results been disseminated to communities of interest?Presented parasite control programs at WV extension winter dinner meetings, University of Delaware Seminar Series, Buckeye Shepherds Symposium, WV Cattlemen's College, NC Sheep and goat workshop and National Texel Sheep Breeder's meeting Across the different workshops I have participated over 500 producers have learned more about managing parasites in their flocks. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? St. croix sheep are generating a greater response to H. contortus cuticle antigen consistent with their early response and clearance of this parasite. Cuticle antigen maybe a useful target to develop better vaccines to manage H. contortus in susceptible breeds. Differences between STC-derived cell populations suggest a synergistic role of monocytes and lymphocytes, contributing to a greater reduction in larval morbidity when together in culture. No differences were observed between homologous SUF-derived cell populations and SUF-derived PBMC. These data suggest potential differences in monocyte activation states between breeds. Complement/antibody complexes inhibit larval motility through enhanced larval aggregation which may be critical in early larval clearance ofH. contortusin sheep. Larval expulsion via neutrophil extracellular trap formation may be important in the early immunological responses to H. contortus prior to L4 stage. The data suggests neutrophils as a vital innate immune cell to drive a proper Th2 response to Haemonchus contortus parasitic infection. Gain and carcass merit of TX-sired lambs is equivalent to SU-sired lambs, however there is a significant amount of sire variation which has the potential to impact performance of Katahdin crossbred lambs. These data indicate a need to further evaluate variation within the Texel breed to better identify superior rams. While trefoil does not prevent infection with H. contortus it limits the size of the infection and has similar effects as grazing SL on infected lambs.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Jacobs, J.R., K.N. Sommers, A.M. Zajac, D.R. Notter, S.A. Bowdridge. 2016. Early IL-4 gene expression in abomasum is a critical difference in resistance to H. contortus. Parasit. Immunol. 38:333-339.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Elkins, C., S.A. Bowdridge. 2016. Infection with H. contortus shifts genera diversity of fecal microbiome. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Garza, J., S.A. Bowdridge. 2016. Serum induces H. contortus larval aggregation via complementand antibody complexes that differ by larval stage. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Garza, J., S.A. Bowdridge. 2016. Haemonchus contortus induced neutrophil extracellular trap formation differs between resistant and susceptible breeds of sheep. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Garza, J., S.A. Bowdridge. 2016. Haemonchus contortus fourth stage larval excretory/secretory protein inhibits serum-mediated larval aggregation. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Jacobs, J., S.A. Bowdridge. 2016. Interleukin-4 and its downstream targets are rapidly upregulated in immune cells of St. Croix sheep exposed to H. contortus larval antigen in vitro. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Jacobs, J., J. Garza, S.A. Bowdridge. 2016. RNA-seq analysis of immune cells cultured with H. contortus larval antigen reveals differential gene expression in parasite resistant and susceptible sheep. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Middleton, D., J. Keenan, J. Garza, S.A. Bowdridge. 2016. RNA-seq reveals differential gene expression in abomasal lymph node during H. contortus infection. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Russ, B., J. Garza, S.A. Bowdridge. 2016. Isolation of third stage H. contortus cuticle and cuticle protein. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Shepherd, E.A., J. Garza, S.A. Bowdridge. 2016. Quantification of H. contortus larval death after culture with host immune cells by measuring larval ATP. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Weaver, A.R., D.L. Wright, M.A. McCann, A.M. Zajac, S.A. Bowdridge, S.P. Greiner. 2016.Evaluation of terminal sire breeds for hair sheep production systems on lamb birth, weaning, and grazing performance. ASAS Southern Section Meeting San Antonio TX.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Bowdridge, S.A., D. Mata-Padrino, D.P. Belesky. 2016. Effect of fish meal supplementation rate on parasitism and performance of grazing lambs. ASAS Southern Section Meeting. San Antonio, TX.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Bowdridge, S.A., C.S. Sotomaior, M.A. McCann, A.M. Zajac, S.P. Greiner. 2016. Effect of sire breed on gain, carcass characteristics and parasite resistance of Katahdin crossbred feedlot-finished lambs. ASAS Southern Section Meeting San Antonio, TX.


    Progress 10/01/14 to 09/30/15

    Outputs
    Target Audience:Target audience were small ruminant producers, scientists and parasitologists working with small ruminants Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Multiple graduate students (Jesica Jacobs, Denzel Middleton, Brynnan Russ and Elizabeth Shepherd) worked on projects under the program. Aditionally one postdoctoral research fellow (Dr. Javier Garza) assisted in the collection and analysis of data for these projects. Additionally this project helped train two undergraduate students in research techniques How have the results been disseminated to communities of interest?Presented parasite control programs at WV extension winter dinner meetings, University of Delaware Seminar Series, Buckeye Shepherds Symposium, WV Cattlemen's College, NC Sheep and goat workshop and National Texel Sheep Breeder's meeting Across the different workshops I have participated over 500 producers have learned more about managing parasites in their flocks. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? At time points 12 and 18 hours post infection using 5 µg/mL, proliferation was determined to be significantly higher in St. Croix PBMCs when compared to Suffolk PBMCs (P <0.001). From this data, experiments were performed at 6 hours, 12 hours and 18 hours using St. Croix and Suffolk PBMCs and 5 µg/mL cuticle antigen to each well; controls used in these experiments were: conA (5 µg/mL), LPS (10 µg/mL), CLA (10 µg/mL), and CWA (10 µg/mL). Cuticle antigen initiated a significantly greater amount of proliferation in St. Croix PBMCs than Suffolk PBMCs at 12 hours (P<0.05) but proliferation did not significantly differ from controls LPS or CLA. At 6 there was no significant different in proliferation between the different treatments. At 18 hours, there was a significantly higher amount of proliferation in the conA, LPS, CLA, and CWA when compared to cuticle antigen in both St. Croix and Suffolk breeds (P<0.05). STC-derived monocytes reduced larval ATP (0.10 µM ATP) to the same extent as PBMC (0.10 µM ATP), which was significantly lower than STC-derived lymphocytes alone (0.15 µM ATP) (P < 0.001). In a separate experiment, larval ATP was significantly reduced when co-cultured with STC-derived PBMC (0.06 µM ATP) or monocytes (0.9 µM ATP) compared to larvae exposed to STC-derived lymphocytes alone (0.11 µM ATP) (P < 0.001). ATP concentration of larvae exposed to SUF-derived PBMC, monocytes, or lymphocytes were not significantly different (0.09, 0.09, 0.10 µM ATP respectively). In both experiments, larval treatment groups exposed to cells were significantly reduced from untreated control larval ATP (0.26 µM ATP) (P < 0.001). No difference of breed or immune status were observed in serum-induced L3 aggregation (80%, P > 0.05), as such, when serum from primed Suffolk sheep was used, xL3 (62%) and L4 (40%) aggregation was significantly reduced compared to L3 (80%, P < 0.001). Removal of either complement or antibody effectively eliminated L3 aggregation compared to primed Suffolk serum (P < 0.001) and aggregation was restored by addition of purified antibody to antibody depleted serum. Use of fluorescence-labeled anti-sheep IgG antibody allowed documentation of IgG bound specifically to serum complexes within L3 masses and was present only in larvae incubated with normal serum and a combination of complement and antibody depleted serum. Larval binding was higher in primed and naïve St. Croix derived neutrophils (93% and 68%) compared to Suffolk (78% and 45%, P < 0.001). Binding of L3 by neutrophils was dependent on immune status in both breeds and was reduced when cells were incubated with xL3 and L4. There was a slight trend observed with PH groups having a higher amount of IL-4 secretion (P = 0.051) These data taken together indicate that St. croix sheep are generating a greater response to H. contortus cuticle antigen consistent with their early response and clearance of this parasite. Cuticle antigen maybe a useful target to develop better vaccines to manage H. contortus in susceptible breeds. Differences between STC-derived cell populations suggest a synergistic role of monocytes and lymphocytes, contributing to a greater reduction in larval morbidity when together in culture. No differences were observed between homologous SUF-derived cell populations and SUF-derived PBMC. These data suggest potential differences in monocyte activation states between breeds. These data indicate that complement/antibody complexes inhibit larval motility through enhanced larval aggregation which may be critical in early larval clearance ofH. contortusin sheep. These data suggest that larval expulsion via neutrophil extracellular trap formation may be important in the early immunological responses to H. contortus prior to L4 stage. The data suggests neutrophils as a vital innate immune cell to drive a proper Th2 response to Haemonchus contortus parasitic infection.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2016 Citation: Jacobs, J.R., K.N. Sommers, A.M. Zajac, D.R. Notter, S.A. Bowdridge. 2016. Early IL-4 gene expression in abomasum is a critical difference in resistance to H. contortus. Parasit. Immunol. 38:333-339.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Elkins, C., S.A. Bowdridge. 2016. Infection with H. contortus shifts genera diversity of fecal microbiome. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2016 Citation: Garza, J., S.A. Bowdridge. 2016. Serum induces H. contortus larval aggregation via complement and antibody complexes that differ by larval stage. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Garza, J., S.A. Bowdridge. 2016. Haemonchus contortus fourth stage larval excretory/secretory protein inhibits serum-mediated larval aggregation. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Jacobs, J., S.A. Bowdridge. 2016. Interleukin-4 and its downstream targets are rapidly upregulated in immune cells of St. Croix sheep exposed to H. contortus larval antigen in vitro. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Jacobs, J., J. Garza, S.A. Bowdridge. 2016. RNA-seq analysis of immune cells cultured with H. contortus larval antigen reveals differential gene expression in parasite resistant and susceptible sheep. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Middleton, D., J. Keenan, J. Garza, S.A. Bowdridge. 2016. RNA-seq reveals differential gene expression in abomasal lymph node during H. contortus infection. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Russ, B., J. Garza, S.A. Bowdridge. 2016. Isolation of third stage H. contortus cuticle and cuticle protein. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Shepherd, E.A., J. Garza, S.A. Bowdridge. 2016. Quantification of H. contortus larval death after culture with host immune cells by measuring larval ATP. 61st Annual Meeting AAVP San Antonio, TX
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Weaver, A.R., D.L. Wright, M.A. McCann, A.M. Zajac, S.A. Bowdridge, S.P. Greiner. 2016. Evaluation of terminal sire breeds for hair sheep production systems on lamb birth, weaning, and grazing performance. ASAS Southern Section Meeting San Antonio TX.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Bowdridge, S.A., D. Mata-Padrino, D.P. Belesky. 2016. Effect of fish meal supplementation rate on parasitism and performance of grazing lambs. ASAS Southern Section Meeting. San Antonio, TX.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Bowdridge, S.A., C.S. Sotomaior, M.A. McCann, A.M. Zajac, S.P. Greiner. 2016. Effect of sire breed on gain, carcass characteristics and parasite resistance of Katahdin crossbred feedlot-finished lambs. ASAS Southern Section Meeting San Antonio, TX.


    Progress 10/01/13 to 09/30/14

    Outputs
    Target Audience:Presented programs at WV extension winter dinner meetings, VA-NC producer workshop, National meeting of Katahdin sheep breeders, US animal health association.Across the different workshops I have participated over 500 producers have learned more about managing parasites in their flocks. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?In the past year work under this project has supported training of two MS students and one PhD Student. One undergraduate student has worked in area outlined by this project. Additionally a visiting scholar from Brasil worked on this project learning parasitological experiemtal techniques. How have the results been disseminated to communities of interest?Resutls from these projects have been disseminated to national, regional and localsheep producer groups, Results from these projects have been published in peer-reviewed journals and data presented at national scientific meetings. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? Our objectives were improve carcass merit while maintaining parasite resistance in Katahdin crossbred lambs and to determine effect of protein supplementation on parasitism of grazing lambs Results - obj 1: Analysis of parasitological data indicated no effect of sire during the primary infection; however, sire effects were observed during challenge infection as KT-sired lambs had greatest (P < 0.01) fecal egg count (757 eggs/g) vs SU (266 eggs/g) and TX (462 eggs/g). Upon slaughter, no differences in worm burden of sire groups were observed and no difference was found in growth data between sire groups; however, SU-sired lambs tended to have greater (P = 0.051) ADG vs. KT (0.40 vs. 0.32 kg/d, respectively) but no advantage (P > 0.05) compared to TX-sired lambs (0.35 kg/d). Analysis of REA using ultrasound and direct carcass measurements revealed no difference between SU- (17.2 cm2) or TX-sired lambs (19.6 cm2), however, both groups were different than Katahdin lambs (13.73cm2; P < 0.01). Leg score favored TX (12.8) and SU (12.0) lambs vs KU-sired lambs (11.0; P < 0.05). Gain and carcass merit of TX-sired lambs is equivalent to SU-sired lambs providing data to support use of alternative terminal sires in Katahdin crossbreeding programs without impacting parasite resistance of crossbred progeny Results obj 2: Lambs receiving SR at 2% of BW gained 9.38±0.73 kg whereas lambs receiving 1% SR gained 3.94±0.71 kg (P < 0.0001). Taken over 70d this equated to an ADG of 0.17±0.015 kg/d for lambs receiving 2% versus 0.06±0.015 kg/d of lambs receiving 1% SR. A similar effect was observed for FEC as no SR by GL interaction was observed yet a highly significant effect of SR was detected. Lambs receiving 1% SR had a higher log transformed FEC 2.44±0.05 eggs/g than 2% SR 2.17±0.05 (P < 0.0001). These data demonstrate that lambs supplemented at a rate of 2% BW with a 19% CP ration had lower FEC and greater gain while grazing predominantly fescue pastures. These data provide additional means whereby producers can mitigate the effects of GIN parasitism on growth of grazing lambs.

    Publications

    • Type: Theses/Dissertations Status: Published Year Published: 2015 Citation: Crawford, C.D. 2015. Effects of protein supplementation on parasitism and growth of grazing lambs. MS Thesis West Virginia University.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Garza, J., S.A. Bowdridge. 2015. Texel crossbred lambs show increased resistance Haemonchus contortus. 60th Annual Meeting AAVP, Boston, MA.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Jacobs, J.R., S.A. Bowdridge. 2015. Peripheral immune cells of St. Croix sheep rapidly produce IL-4 in response to Haemonchus contortus antigen in vitro. 60th Annual Meeting AAVP, Boston, MA.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Shepherd, E., J. Garza, S.A. Bowdridge. 2015. Quantification of Haemonchus contortus larval death after culture with host immune cells by measuring larval ATP. 60th Annual Meeting AAVP, Boston, MA.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Crawford, C., D.J. Mata-Padrino, D.P. Belesky, E.E. Felton, S.A. Bowdridge. 2015. Effects of protein supplementation on parasitism in grazing lambs. ASAS Southern Section Meeting, Atlanta, GA
    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Holt, R.M., E.A. Shepherd, A.G. Ammer, S.A. Bowdridge. 2015. Effects of peripheral blood mononuclear cells on Haemonchus concortus larval motility in vitro. Parasit. Immunol. 37:553-556.
    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Jacobs, J.R., S.P. Greiner, S.A. Bowdridge. 2015. Serum interleukin-4 (IL-4) production is associated with lower fecal egg count in parasite-resistant sheep. Vet. Parasitol. 211:102-105
    • Type: Journal Articles Status: Published Year Published: 2015 Citation: Bowdridge, S.A., A.M. Zajac, D.R. Notter. 2015. St. Croix sheep produce a rapid and greater cellular immune response contributing to reduced establishment of Haemonchus contortus. Vet. Parasitol. 208:204-210.
    • Type: Journal Articles Status: Published Year Published: 2015 Citation: MacKinnon, K.M., S.A. Bowdridge, I. Kanevsky-Mullarky, A.M. Zajac, D.R. Notter. 2015. Gene expression profiles of hair and wool sheep reveal importance of IL-13 and other Th2 immune mechanisms for increased resistance to Haemonchus contortus. J. Anim. Sci. 93:2074-2082.


    Progress 11/01/12 to 09/30/13

    Outputs
    Target Audience: Target audiences reached duirng this part year are small ruminant producers that have attended workshops where I have presented information about controlling parasitism. This year I have trained 20 producers in the FAMACHA system. Across the different workshops I have conducted over 300 producers have learned more about managing parasites in their flocks. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? This project has provided training opportunities for 4 M.S. students in the area of parasite immunology, small ruminant production and small ruminant grazing management. Students have conducted research projects and presented data at two different scientific meetings. How have the results been disseminated to communities of interest? Presented programs at WV extension winter dinner meetings, WV spring shepherd's symposium, Davis-Michael 4-H day, WV/VA purebred sheep breeders meeting, WVU Organic Farm Field Day, WV Winter Shepherd's Symposium and FAMACHA training workshops. This year I have trained 20 producers in the FAMACHA system. Across the different workshops I have conducted over 300 producers have learned more about managing parasites in their flocks. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

    Impacts
    What was accomplished under these goals? Gene expression analysis of abomasal mucosa revealed IL-4 expression in challenged Suffolk crossbred lambs on day 10, yet no detection in St. Croix lambs. Lymph node weight was not different between breeds of challenged lambs as both groups averaged 4g, but were significantly different from naïve lambs. In comparison to previous studies, a 7 day delay in IL-4 expression and a 5 day delay in lymph node hypertrophy of parasite-susceptible sheep are associated with differences in worm burden. St. Croix lambs at day 10 had an average of 16 larvae in the abomasum compared to Suffolk crossbred lambs averaging 530 (P < 0.05). Reduction of IL-4 and lymph node weight in St. Croix sheep by day 10 indicates a resolution of infection while increases observed in Suffolk crossbred lambs indicate an initiation of immune response. Fecal egg counts of Texel crossbred lambs are not significantly different from St. Croix but are different from Suffolks lambs (939 vs 3836 eggs/g; P< 0.01) during a primary infection. A similar trend was also observed during a challenge infection, where Texel crossbred and St Croix lambs have lower FEC than Suffolk lambs, however, Texel crossbred lambs never reduce FEC to zero as is observed in St Croix lambs. Evaluating worm load in the abomasum, St Croix and Suffolk lambs were killed at 10d followed infection whereas Texel crossbred lambs were killed on day 49. However St. Croix generated the lowest worm burden at 16, where Suffolk and Texel were comparable. Analysis of hematological parameters of H. contortus infection indicated that group 3 (31.48 ± 0.35) had higher PCV than groups 1 (29.81 ± 0.35) and 2 (29.47 ± 0.35) (P < 0.001), although all were within normal range. Analysis of FEC resulted in a tendency for differences between groups (P = 0.11). Further pairwise comparisons indicated that FEC of group 2 (519 eggs/g ± 24) was lower than group 1 (684 eggs/g ± 24) (P < 0.05) and not different than group 3 (630 eggs/g ± 24) (P = 0.15). No differences in gain were observed

    Publications

    • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: K.N. Sommers, Jacobs, J. and S.A. Bowdridge. 2014. Delayed immune responses of parasite-susceptible sheep during Haemonchus contortusinfection are associated with greater larval burden. Proc. 59th Meeting Am. Assoc. Vet. Parasitol. Denver, CO.
    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Crawford, C.D., D. Mata-Padrino, D. Belesky and S.A. Bowdridge. Effects of protein supplementation on growth of parasitized organic lambs while grazing. 2014 ASAS Southern Section Meeting Dallas, TX
    • Type: Conference Papers and Presentations Status: Accepted Year Published: 2014 Citation: Houdijk, J., and S.A. Bowdridge. 2014. Can protein supplementation reduce reliance on anthelmintics in small ruminant production systems? 13th Intl Congress of Parasitology (ICOPA). Mexico City, MX