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ARS Home » Southeast Area » Booneville, Arkansas » Dale Bumpers Small Farms Research Center » Research » Publications at this Location » Publication #354548

Research Project: Sustainable Small Farm and Organic Production Systems for Livestock and Agroforestry

Location: Dale Bumpers Small Farms Research Center

Title: Examining relationships between production and gastrointestinal nematode (GIN) measures in organic and conventionally reared Katahdin lambs

item Burke, Joan
item PICKETT, AUTUMN - Southern Arkansas University
item HOWELL, BERLIN - University Of Arkansas
item Wood, Erin
item ACHARYA, MOHAN - University Of Arkansas
item MILLER, JAMES - Louisiana State University

Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 12/15/2017
Publication Date: 2/4/2018
Citation: Burke, J.M., Pickett, A., Howell, B., Wood, E.L., Acharya, M., Miller, J.E. 2018. Examining relationships between production and gastrointestinal nematode (GIN) measures in organic and conventionally reared Katahdin lambs. Journal of Animal Science. 96 (E-Suppl. 1), 71-72.

Interpretive Summary:

Technical Abstract: Katahdin sheep numbers are growing in the Southeastern US. It is a breed committed to the sheep industry’s goal of eradicating Scrapie by selecting for sheep with RR or QR at codon 171. Gastrointestinal nematodes remain a threat to the health and well-being of sheep due to widespread anthelmintic resistance and lack of effective dewormers. The objective was to examine effect of BW and body condition score (BCS), and scrapie genotype on GIN infection in organic (ORG) and conventionally (CON) raised Katahdin lambs. Between 2014 and 2017, certified ORG (n = 100) and CON (n = 541) lambs born in fall (Oct-Dec) and winter (Feb-Mar) were raised on grass pastures and supplemented with a grain product as needed or when forage quality was limiting. Lambs were weaned at ~ 90 d of age and BW and BCS determined at ~ 60, 90, 120, 150, and 180 d of age. On d 90, 120, and 150, fecal and blood samples were collected to determine fecal egg counts (FEC) and blood packed cell volume (PCV), respectively, and a FAMACHA score assigned. Scrapie genotype was determined on all registered lambs, but not all commercial. There were 33 QQ, 212 QR, and 147 RR genotypes. Data were analyzed using SAS to examine correlations among variables, regression, and repeated measures using Proc mixed; FEC were log transformed. FEC were initially lower in ORG lambs, but higher by 150 d (management x day, P < 0.001), but PCV was higher (P < 0.001) and FAMACHA lower (P < 0.001) in ORG than CON lambs. The QQ genotype was associated with higher PCV than QR or RR (P = 0.01), but did not influence BW, BCS, or FEC. There was a negative relationship between BCS and FEC (P < 0.001), and a positive relationship between BCS and PCV (P < 0.001). In addition, higher BW and BCS were associated with improved GIN measures on date of measurement and subsequent dates (P < 0.001). Higher PCV and lower FAMACHA scores were associated with similar trends at subsequent samplings (P < 0.001), but not for FEC. Good nutrition leading to higher BW and BCS was associated with greater resilience to GIN post-weaning. While the industry strives to eliminate QQ genotypes, these data suggest possible resilience to GIN associated with QQ.