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United States Department of Agriculture

Agricultural Research Service

Research Project: A Systems Approach to Control Gastrointestinal Nematodes in Organic Small Ruminant Production: Identification of Resistant Animals

Location: Dale Bumpers Small Farms Research Center

Project Number: 6227-21310-009-98
Project Type: General Cooperative Agreement

Start Date: May 01, 2012
End Date: Apr 30, 2014

Objective:
The objective of this cooperative research project is to identify unique genetic markers related to internal parasitism of small ruminants and to examine the effects of conventional or forage finished lamb on parasite infection, weight gain and pasture quality, including soil quality, number of off-farm inputs (fertilizer and feed supplement), and carrying capacity.

Approach:
Blood, tissue, and fecal samples will be collected from select populations of small ruminants with known parasitism history and(or) expected progeny differences (EPD) for internal parasitism and growth traits. Genomic DNA will be purified from buffy coat or tissue samples and screened for single nucleotide polymorphisms in candidate genes. Genes will include cytochrome P450 3A family, and prolactin. In addition, plasma will be screened for unique microRNA populations. Identification of unique polymorphisms will be related to fecal egg counts (FEC), FEC EPDs, growth traits, and reproductive success using regression models and analysis of variance. Additionally, ewes/lambs will be randomly assigned to forage systems: 1) conventional, continuous grazing of grass pastures with grain based supplement during early lactation and at weaning; 2) organically managed, continuous grazing grass pastures (organic) with certified organic grain based supplement to ewes and lambs as in System 1; 3) rotationally grazed without supplementation; 4) rotationally grazed on certified organic pasture without supplementation. For rotational grazing, there will be 10 subplots within a rep, moving sheep every at least every 3 days, not to return for at least 28 days (in the case of a drought or low forage availability, additional plots will be used). Lambs should reach processing weight by fall or can continue into cool season grazing until winter (forage finished lambs may take longer and will continue until reaching a minimum of 55 kg). Sheep will be selectively dewormed and fecal egg counts and degree of anemia will be determined at the time of weighing.

Last Modified: 4/17/2014
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