Table 3.

Potential and commercialised immune-related markers of GIN parasite resistance.

Trait	Description	Advantages	Disadvantages	Application
Serum antibodies	Phenotypic, enzyme-linked immunosorbent assay (ELISA).	Routine laboratory procedure	(i) Invasive sampling (ii) Off-farm (iii) Not sensitive to infection level (iv) Transient up regulation	Research
Salivary antibodies		(i) Relatively easy collection (ii) Routine laboratory procedure	(i) Off-farm (ii) Requires certain level of infection for detection	Commercialised http://www.kelso.co.nz/partners/  carla%c2%ae-saliva-test-measuring-  parasite-immunity-in-sheep/
Faecal antibodies		(i) Relatively easy collection (ii) Routine laboratory procedure	(i) Off-farm (ii) Involves faecal collection (iii) Low accuracy	Research
Blood eosinophilia	Phenotypic, morphological cell differentiation after staining.	Routine laboratory procedure	(i) Invasive sampling (ii) Off-farm (iii) Trained technician required to count eosinophils (iv) Transient up regulation	Research
Ghrelin levels in blood	Phenotypic, ELISA platform. Higher levels in susceptible sheep following infection.	Routine laboratory procedure	(i) Invasive collection (ii) Off-farm (iii) Transient up regulation (iv) Only tested in resistant and susceptible lines	Research
Cutaneous hypersensitivity reactions	Phenotypic, cutaneous injection of sensitised antigen to measure immune function.	(i) Tests responds to a range of diseases (ii) Noninvasive readouts (iii) Potential for on-farm development	(i) Involves injection of antigens into animals (ii) 2–24 hr time delay for readout	Research