Fig. 1
Schematic illustration of experimental design and Ostertagia life cycle. (a) Experimental design showing a timeline for tissue collection which correspond to late L3 to early L4 (3–5 dpi), mid to late L4 (7–9 to 10 dpi) and adult stages (21 dpi). A total of 24 Holstein steers were used in the experiment. Control animals (n = 6) were uninfected and received phosphate-buffered saline (PBS) only. Infected animals (n = 18) received oral infection by O. ostertagi stage 3 larvae on day 0 and were euthanized on Day 3, 5, 7, 9, 10, or 21 post-infection. During necropsy, abomasal fundic and pyloric mucosa were collected, snap-frozen in liquid nitrogen and stored at −80C untiled used. Frozen tissues were pulverized and stored at −80 °C until processed for total RNA isolation. (b) Ostertagia ostertagi life cycle. O. ostertagi has a direct life cycle which consists of free-living and parasitic stages. During the parasitic phase, animals are infected during grazing by ingesting infective L3 on the pastures. Following infection, the L3 quickly reach abomasum and burrow into the gastric glands where they develop into L4 and young adults. The adult worms enter into the abomasal lumen where they mate and produce eggs. Free-living stage starts when nematode eggs are released onto the pasture in feces. The eggs then hatch to L1 and molt into L2 and infective L3 on pasture. Next cycle begins when grazing animals ingest the infective L3.
