104 Evaluation of Pre-Weaning and Grazing Performance of Terminal Sire Breeds for Hair Sheep Production Systems

Weaver, Andrew R; Wright, Donald L.; Notter, D. R.; Zajac, Anne M.; Bowdridge, Scott A; Greiner, Scott Patrick

doi:10.2527/ssasas2017.0104

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“…6 Evaluation of these breeds in U.S. hair sheep crosses observed improved muscling in the Texel with similar parasite resistance traits to the purebred hair lambs. 7 Good et al 8 reported reduced faecal egg count (FEC) in Texel compared to Suffolk sheep in the United Kingdom, where Teladorsagia circumcincta infections are more common in these temperate climates. Major histocompatibility complex II (MHCII) haplotypes, including the DRB1*1101 allele, have been associated with GIN resistance in Scottish Blackface, 9 Suffolk 10 and Texel sheep.…”

Section: Introductionmentioning

confidence: 99%

Immune mechanisms of Texel sheep to adult and egg stages of Haemonchus contortus

Weaver

Garza

Greiner

et al. 2021

Parasite Immunology

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Experimental Haemonchus contortus (Hc) infections revealed that Texel sheep have faecal egg counts (FEC) comparable to parasite-resistant St. Croix but adult worm burden comparable to parasite-susceptible Suffolk sheep. The aim of these studies was to further investigate the mechanism causing this disparity. Cellular and humoral immune responses to adult-and egg stage Hc were compared amongst St. Croix, Texel and Suffolk sheep. Adult worms and eggs were exposed to peripheral blood mononuclear cells (PBMC) and serum from the three breeds in vitro. There was a greater IgA binding to eggs when treated with St. Croix and Texel serum (p < .05), and these eggs exhibited a lower hatch rate (p < .05) when exposed to serum and PBMC. Adult worms exposed to St. Croix and Texel-derived PBMC, and serum had greater binding around the head and reproductive structures than worms exposed to Suffolk-derived cells and serum. Consequently, egg release tended to be affected by breed (p = .09). To further examine differences, Suffolk and Texel lambs (n = 5/breed) were infected with 10,000 Hc L3 for 30 days. Suffolk sheep had greater egg release per worm than Texel (3.8 vs. 2.1 eggs/worm). Taken together, these data would indicate one of the mechanisms in Texel's targeting adult-stage Hc reducing worm fecundity.

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