ACSRPC | Genetics

Genetic control of internal parasites

Selecting animals with the ability to resist and tolerate interal parasite infections is one of the best long-term strategy for managing internal parasite problems in small ruminants. Parasite resistance (usually quantified by fecal egg counts) is a moderately heritable trait and there is considerable within and between breed variability. Parasite resilience is less heritable, but is more easily estimated on the farm, using the FAMACHA© system and Five Point Check©. There are genetic correlations between fecal egg counts and FAMACHA© scores.

Articles

Blueprint for Selecting Parasite Resistant Sheep: A Shepherd's Perspective. Kathy Bielek, Misty Oaks Farm, Wooster, Ohio [Timely Topic, January 2014].
Breed type and resistance: building a parasite-resistant meat goat herd at North Carolina A&T State University. Niki Whitley and Sara Beth Routh, North Carolina A&T State University. [Timely Topic, May 2013].
Building internal parasite resistance in small ruminants: new ATTRA publication focuses on animal selection; Linda Coffey, National Center for Appropriate Technology/Sustainable Agriculture Information Network [Timely Topic, October 2012].
How can artificial insemination (AI) further parasite resistance in sheep? Joan Burke, Stephan Wildeus, Roxanne Newton, and Kathy Bielek [Timely Topic, February 2014].
How Does Selection for Parasite Resistance in Katahdin Sheep Affect Other Important Traits? Eastern Alliance for Production Katahdins [October 2022].
Impact of selection and breed on resistance. Ken Andries, Kentucky State University [Timely Topic, November 2017]
Resistance: it's a gene frequency thing; Will Getz, Fort Valley State University [Timely Topic, January 2013].
Selection for Parasite Resistance; Joan Burke, Dale Bumpers Small Farm Research Center, USDA-ARS, Booneville, Arkansas [Timely Topic, October 2017].
Stop Selecting Sissy Sheep (and Goats)! Dr. Gareth Bath, University of Pretoria, South Africa [Timely Topic, July 2016]
The value of using FEC EBVs. Joan Burke, USDA-ARS [Timely Topic, October 2022]

Conference proceedings

Genetics of Parasite Resistance in Small Ruminants; David Riley and Lauretta Ngere, Texas A&M University; 10th Anniversary Conference of the American Consortium for Small Ruminant Parasite Control, Fort Valley, Georgia [May 2013].
Practical Breeding for Sheep Resistance and Resilience to Haemonchus Contortus: Trial to Select Haemonchus Contortus Resistant Sheep Unders Summer Rainfall Field Conditions. W4: What Works With Worms Congress, Pretoria, South Africa [2015].

External links

Caprine haemonchosis: optimism of breeding for disease resistance in developing countries. Kush Shrivastava et al. Journal of Applied Animal Research. [March 2022].
The genetics of resistance to gastrointestinal parasites in Florida Native sheep. Zaira M. Estrada Reyes, Owen Rae, Carol Postley, and Raluca G. Mateescu. University of Florida Extension [January 2021]
Genetic markers for resistance to gastrointestinal parasites in sheep and goats from the southern region of the US. Zaira M. Estrada Reyes, Yoko Tsukahara, Arthur L. Goetsch, Terry A. Gipson, Tilahun Sahlu, Richard Puchala, and Raluca G. Mateescu. University of Florida Extension [February 2022].
Strategies for Genetic Improvement of Parasite Resistance in Sheep. David R. Notter, Virginia Tech.

Factsheets

Best Management Practices for Controlling Internal Parasites in Small Ruminants: Genetic Selection: Using Crossbreeding and Estimated Breeding Values. Scott Bowdridge and Andrew Weaver, West Virginia University [April 2024].
Best Management Practices for Controlling Internal Parasites in Small Ruminants: Genomic-enhanced EBVs. Mohan Acharya, Lincoln University of Missouri [February 2024].
On-farm selection for resistance to parasites. Jim Morgan, Round Mountain Consulting [Best Management Practices, January 2021] --En Español--
Simple genetic-selection strategies to manage the barber pole worm. Dave Scott. National Center for Appropriate Technology/The National Sustainable Agriculture Information Service (ATTRA) [June 2018].
Tools for managing internal parasites in small ruminants: animal selection; Linda Coffey; National Center for Appropriate Technology/The National Sustainable Agriculture Information Service (ATTRA) [May 2012].

Podcasts

Genetic Resistance to Parasites in Goats (with Andrew Weaver) - For the Love of Goats [May 2021]
Genetic selection for parasite resistance (with Scott Bowdridge). ASI Research Update. American Sheep Industry Association [June 2021].

Research

Are Dorper Crossbred Ewes As Tolerant to Intestinal Parasites As St. Croix Or Katahdin Ewes in the Southeastern United States?; J. Burke; Southern Section of the American Society of Animal Science [February 2002].
Are Dorper Crossbred Weaned Lambs As Tolerant to Intestinal Parasites As St. Croix Or Katahdin Lambs in the Southeastern United States?; J. Burke; Southern Section of the American Society of Animal Science [February 2002].
Effect of sire fecal egg count estimated breeding value on parasite resistance traits in Haemonchus contortus infected Katahdin lambs; A. Weaver, D. Wright, S. Greiner, and S. Bowdridge. Small Ruminant Research [June 2023].
Gastro-intestinal Parasite Infestation (GIP) and its associated effects on growth performance of bucks on a pasture-based test in Maryland (pages 24-29); K. Nadarajah, S. Schoenian and D.L. Kuhlers; Sheep & Goat Research Journal [July 2015].
Pasture-raised Katahdin and Katahdin crossbred lambs: growth and parasite resistance; N. Whitley, D. Jackson, D. Cazac, J. Miller, J. Burke, and R. Subburathinam; Southern Section of the American Society of Animal Science.
Relative resistance of Dorper crossbred ewes to gastrointestinal nematode infection compared with St. Croix and Katahdin ewes in the southeastern United States; J.M. Burke and J.E. Miller; Veterinary Parasitology [August 2002].
Resistance to Gastrointestinal Parasites in Dorper, Katahdin, and St. Croix Lambs in the Southeastern United States; J. Burke and J. Miller; Small Ruminant Research [August 2004].

Videos

Genetic selection for parasite resistance. Reid Reddin. Texas A&M AgriLife. [2019]
Selection for parasite resistance. Joan Burke. American Sheep Industry Association [2017]
Weeding out the wormy ones Part 1 | Part 2 | Part 3 - Northeastern Small Ruminant Parasite Control [2020]

Last updated 02.14.24. Links verified 11.02.23.