IMPROVING PARASITE RESISTANCE IN TEXEL SHEEP

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1015811
• Project Start Date: Apr 4, 2018
• Project End Date: Mar 31, 2023
• 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
Texel sheep are well known for their superior carcass traits, but only in the last decade have researchers discovered enhanced resistance to helminth parasitism. In previous studies at WVU, Dorset-Texel crossbred sheep had lower fecal egg counts than Suffolk sheep yet were more similar to known parasite-resistant St. Croix. The value in selecting or enhancing this trait in Texel sheep is to position the breed to become the premier terminal sire breed that has parasite-resistance. To be able to accomplish this task requires genetic evaluation tools that have not been previously utilized by Texel breeders in the US. In the past year performance data on the WVU Texel flock has been submitted to LambPlan™ to generate estimated breeding values (EBV) for a variety of traits including fecal egg count (FEC). Of the 60 Texel lambs entered into LambPlan™ in 2017 approximately 45% came from WVU. The goal of this project is to manage Texel sheep to generate FEC data and to provide superior breeding stock to producers in the US who aim to capitalize on superior carcass traits and parasite resistance found in Texel sheep. Genetic selection within the Texel breed to improve parasite resistance has the potential to make a long-lasting impact on sheep production in the eastern US.

Animal Health Component

90%

Research Effort Categories

Basic

10%

Applied

90%

Developmental

0%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
313	3610	1110	100%

Knowledge Area
313 - Internal Parasites in Animals;

Subject Of Investigation
3610 - Sheep, live animal;

Field Of Science
1110 - Parasitology;

Keywords

sheep production

parasite management

Goals / Objectives
Texel sheep are well known for their superior carcass traits, but only in the last decade have researchers discovered enhanced resistance to helminth parasitism. In previous studies at WVU, Dorset-Texel crossbred sheep had lower fecal egg counts than Suffolk sheep yet were more similar to known parasite-resistant St. Croix. The value in selecting or enhancing this trait in Texel sheep is to position the breed to become the premier terminal sire breed that has parasite-resistance. To be able to accomplish this task requires genetic evaluation tools that have not been previously utilized by Texel breeders in the US. In the past year performance data on the WVU Texel flock has been submitted to LambPlan™ to generate estimated breeding values (EBV) for a variety of traits including fecal egg count (FEC). Of the 60 Texel lambs entered into LambPlan™ in 2017 approximately 45% came from WVU. The goal of this project is to manage Texel sheep to generate FEC data and to provide superior breeding stock to producers in the US who aim to capitalize on superior carcass traits and parasite resistance found in Texel sheep. Genetic selection within the Texel breed to improve parasite resistance has the potential to make a long-lasting impact on sheep production in the eastern US.

Project Methods
Objective 1: Further develop WVU Texel flock as a research-driven leader in genetics for parasite resistanceIn 2012, we conducted an experiment using Texel crossbred sheep and found a remarkable amount of resistance to the parasite Haemonchus contortus. In the following year a project was planned in collaboration with Virginia Tech where Texel rams related to those that sired lambs in our 2012 project would be mated to Katahdin ewes. That project was to run for three years from 2014 to 2017 and data from that project have indicated that Texel crossbred lambs grow better on grass while maintaining an acceptable level of parasitism when compared to lambs sired by Suffolk rams. Different sires were used for each breeding, and results were variable. Since there was no metric to compare sires within breed for parasite resistance, we were limited to comparing pedigrees which was ultimately ineffective. Thus a critical need exists to develop a metric to identify superior Texel sires with parasite resistance. Currently, no Texel producers submit FEC data to NSIP, and in 2016 only one producer submitted typical production data to NSIP, thus it is critical that a flock be developed that is representative of the US flock and where data for typical traits and FEC are submitted to NSIP.Objective 1a: Increasing flock sizeIn 2016 a local Texel producer suddenly passed away and we were offered an opportunity to purchase his Texel flock and this became the base Texel flock which included 20 mature ewes, 16 lambs and 1 mature ram. After a request to the national Texel association, we received a donation of 6 ewes from various producers. At the national show and sale in 2016 we purchased the champion ram and 4 ewes adding to our flock size. With the new additions we have improved our linkage to other flocks in the US. This year we purchased 7 more ewe lambs and one mature ram. We have retained approximately 20 ewe lambs as replacements and animals for research. With new rules imposed by the WVU veterinary staff, where ewe lambs cannot be bred until 18 months of age, it will be critical to keep a large number of replacement ewe lambs to increase flock size while being able to sell high quality replacements.To accomplish research and extension needs we need to grow our mature ewe flock size to approximately 100 ewes. Over the next 5 years we will retain a large proportion of ewe lambs born and continue to purchase 5-10 ewe lambs or mature ewes. Selection of replacement ewe lambs will be based on estimated breeding values (EBV) generated by NSIP. Semi-annual data will be submitted to NSIP to permit selection of individuals. With a delay in breeding replacements culling rate within the ewe flock will remain low. To the left is a schematic outlining plans for growing the flock to 100 ewes.Objective 1b: Improving genetic composition of WVU Texel flockTexel sheep were first imported to the US in 1985. Since then the breed has been developed further by researchers at USDA-MARC and Dr. Charlie Wray of Minnesota. Dr. Wray is a private producer who has been importing Dutch and British semen for the past twenty years and is a national leader in promoting genetic evaluation of Texel sheep. Each year of the project new Texel rams will need to be sourced that come from flocks enrolled in NSIP and from producers submitting data to NSIP. In recent years we have purchased rams from Dr. Wray and will continue to in the future to improve connectivity with his flock. Currently only Dr. Wray and WVU are submitting data to NSIP. Lack of diversity in the US Texel flock prompts the need to import new genetics from overseas. For the past seven years there has been a moratorium on importation of semen from the UK. However, a successful importation of over 500 straws of Texel semen was accomplished in November 2017. A Texel breeder in Georgia (Patrea Pabst) organized the importation and made a selection of 4 rams to producers in the US. We purchased 10 straws of a ram called Cambwell Trademark. Cambwell Trademark was a triplet. He is now a 4 shear ram and has 350 offspring in the UK. His index is 450 and is in the top 1% of Texel sires. Semen has been sold to Sweden, Brazil and Belgium where he has made an impact. Offspring have been sold to Holland, Switzerland and Italy. His sire, Sportsmans Supreme, his mother is a massive full sister Cambwell Robroy and Cambwell Socrates and a half-sister to the outstanding breeder Cambwell Taurus. Over the next five years we aim to obtain additional semen from rams with low EBV for FEC. One ram that was not collected this year is Cambwell Untouchable. This ram is a trait leader for FEC and in the top 1% of Texel rams in the UK. While we only bred 5 ewes this year using AI. We plan to increase that number annually to expand our genetic diversity within our flock and make those genetics available to other producers in the US through sales that emphasize genetic merit.Objective 2: Collecting fecal egg count data to initiate FEC EBV for Texel sheepThere is only one breed of sheep in the US that consistently reports FEC data to NSIP and that is the Katahdin breed. Recently other breeds have begun to submit data and early EBV have been generated for Dorset, Suffolk and Polypay sheep. However, none of the breeds recently submitting data have any data that would indicate a substantive amount of resistance to helminth parasites. Alternatively, Texel sheep have been reported to have greater FEC reduction yet selection of superior individuals is limited due to lack of producer participation in NSIP and submission of data. Therefore, to generate a FEC EBV for Texel sheep FEC data will need to be collected from flocks that are genetically connected.To accomplish this objective, producers will need to collect feces from lambs at weaning and again between 90 and 120 days of age. Since there is limited genetic diversity in the US Texel flock, connectedness between flocks is relatively high thus, any data submitted to NSIP should result in FEC EBV within 3 years of data collection. However, the limiting factor in getting producers to submit data is not collecting fecal samples but rather getting fecal egg counts performed on those samples. We propose to use knowledge and facilities at WVU to provide Texel producers a site to have FEC done to submit data to NSIP.For WVU to process fecal samples for producers, those submitting samples will have to provide evidence that they are enrolled in NSIP and will submit data to NSIP. To accommodate those not enrolled we will provide assistance in enrolling their flocks into NSIP by creating a "how-to" video and email/phone assistance with data submission. Funds from this project will be used to process samples and to store and return data to producers. Producers submitting samples are responsible for paying for sample shipment. It will be made clear that these data are to be used for the purposes of genetic evaluation and are not a diagnosis of disease.A critical component to the completion of this objective is to collect fecal samples from our flock as well. Weaning and post-weaning fecal samples were collected from the WVU Texel flock in 2017 and submitted to NSIP for evaluation. As there were so few samples relative to the size of a breed, no data have been calculated yet. It is our expectation that by the end of this project we will have submitted and had enough submissions for others Texel producers that a reliable EBV can be calculated.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:During this period target aduiences reached includes stakeholders, producers, undergraduate students and scientists 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?Results were dissemniated though talks at the American Sheep Industry National Meeting as well as ASI podcasts What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? This year NSIP allowed calculation of weaning and post-weaning FEC breeding values for Texel sheep. As a component of this project we processed 500 fecal samples for producers across the country and those producers were able to submit data to NSIP

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Shepherd, E.A., S.P. Greiner, S.A. Bowdridge. 2020. Characterization of ovine monocyte activity when cultured with Haemonchus contortus larvae in vitro. Parasit. Immunol. doi.org/10.1111/pim.12773
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Crawford, C.D., D.J. Mata-Padrino, D.P. Belesky, S.A. Bowdridge. 2020. Effects of supplementation containing rumen by-pass protein on parasitism in grazing lambs. Sm. Rum. Res. Doi:10.1016/j.smallrumres.2020.106161
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Shepherd, E.A., S.P. Greiner, B.Russ, S.A. Bowdridge. 2020 Interleukin-13 induces paralysis of Haemonchus contortus larvae in vitro. Parasite Immunol. doi:10.1111/pim.12758
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Middleton, D.M., J.J. Garza, S.P. Greiner, S.A. Bowdridge. 2020. Neutrophils rapidly produce TH2 cytokines in response to larval but not adult helminth antigen. Parasit. Immunol. Doi:10.1111/pim.12679
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Mata-Padrino, D.J., E.M. Pena-Yewtukhiw, D.P. Belesky, W.B. Bryan, S.A. Bowdridge. 2020. Season-long, mixed stocking of a cool-temperate pasture. Grassland Sci. doi:10.111/grs.12281
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Jacobs, J.R., D. Middleton, S.P. Greiner, S.A. Bowdridge. 2020. RNA-sequencing of ovine PBMC after exposure to Haemonchus contortus antigen. Parasit. Immunol. doi: 10.1111/pim.12697

Progress 10/01/18 to 09/30/19

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 year we have we have been able to utilize semen from the UK and generate outbred progeny. Those ram lambs have been offered for sale at NSIP events and performance test sales in VA. We submitted data on 70 lambs this year, representing 50% of data submitted for Texel sheep in the US. To assist Texel breeders in the US submitting data to NSIP we have created a webpage with instructions on submitting data. Additionally we have offered to conduct fecal egg count analysis to Texel producers in the US. We have had 3 producers take advantage of that service and all have submitted theire FEC data to NSIP. After consultation with managers at NSIP, we expect that FEC EBV's will be available within the coming year.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Mata-Padrino, D.J., D.P Belesky, C.D. Crawford, B. Walsh, J.W. MacAdam, S.A. Bowdridge. 2019. Effects of grazing birdsfoot trefoil-enriched pasture on managing Haemonchus contortus infection in Suffolk crossbred lambs. J. Anim. Sci. 97: 172-183
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Middleton, D.M., J.J. Garza, S.P. Greiner, S.A. Bowdridge. 2019. Neutrophils rapidly produce TH2 cytokines in response to larval but not adult helminth antigen. Parasit. Immunol.

Progress 04/04/18 to 09/30/18

Outputs
Target Audience:Sheep producers, specifically Texel sheep breeders across the US. Outputs from this project have also targeted scientists in the field of immunology and parasitology. 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?Data have been reported to producers at regional producer workshops and 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? Three producers in the US submitted fecal samples for evaluation by WVU and data was returned to producers. We know that at least 1 producer submitted fecal egg count data, in addition to data submitted from the WVU Texel flock. This year we sold four rams at the two NSIP sales to porducers in IA, MN and OH.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Maierle, C.M. E.E. Felton, S.A. Bowdridge. 2018. Effect of terminal sire breed on feed efficiency in Katahdin crossbred feedlot-finished lambs. J. Anim. Sci. 96: Supp 1.
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Weaver, A.R., D.L. Wright, D.R Notter, A.M. Zajac, S.A. Bowdridge, S.P. Greiner. 2018. Evaluation of terminal sire breeds for hair sheep production systems on lamb birth, weaning and grazing performance: Year 3. J. Anim. Sci. 96: Supp 1.
• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Weaver, A., J.J. Garza, S.A. Bowdridge. 2018. Immune response to various life stages of Haemonchus contortus differentiates resistance among sheep breeds. 63rd Annual Meeting AAVP Denver, CO.