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| Trait | Description | Advantages | Disadvantages | Application |
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| Worm egg counts (WEC) | Phenotypic, WEC test where the amount of eggs in the faeces is an indicator of adult infection. Eggs counted by microscopy. | (i) Direct measure of infection
(ii) On-farm readout (after training) | (i) Labour intensive and involves collection of faeces from the rectum
(ii) High variability in counts (influenced by diet, age, degree of infection exposure, hypobiosis, and adult density) | Commercial;
http://www.wormboss.com.au/tests-tools/tests/worm-egg-counting.php |
| Genotypic, egg counts in faeces detected by DNA analysis. | (i) Direct measure of infection
(ii) Quicker than phenotypic WEC
(iii) Potentially cheaper as trained experts in worm egg counting are not required | (i) Qualitative only, can’t determine infection level and hence resistance status
(ii) Involves collection of faeces
(iii) Off-farm | Research |
| Phenotypic, lectin assay, use of antibodies to detect eggs in faeces. | (i) Direct measure of infection
(ii) Can distinguish between species by egg morphology | (i) Involves collection of faeces
(ii) Off-farm
(iii) Currently only specific only for H. contortus | Commercial:
http://archive.sheepcrc.org.au/management/worms-flies-lices/
rapid-laboratory-test-for-haemonchus-in-worm-egg-counts.php |
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| Blood loss | Phenotypic, packed cell volume (PCV); involves calculating the percentage of red blood cells from a blood sample. | (i) Direct measurement of infection
(ii) Earlier detection of infection compared to WEC | (i) Invasive
(ii) Not specific to H. contortus infection-other causes of blood loss
(iii) Off-farm | Research |
| Phenotypic, haemonchus dipstick; blood loss measured by amount detected in faeces. | (i) Quick
(ii) No need for highly trained laboratory technician
(iii) On-farm | Blood loss is nonspecific therefore recommended to be used in conjunction with WEC | Commercial:
http://archive.sheepcrc.org.au/management/
worms-flies-lices/haemonchus-dipstick-test.php |
| Phenotypic, FAMACHAⒸ; involves matching eye lid colour with coloured chart indicating level of anaemia. | (i) Noninvasive
(ii) Quick
(iii) No need for highly trained laboratory technician
(iv) On-farm | (i) Nonspecific (other disease induce anaemia)
(ii) Subjective measurement | Commercial:
http://www.acsrpc.org/Resources/famacha.html |
|
| Faecal odour | Phenotypic, infected and uninfected faeces have differential odours detectable by canines. | (i) Detects infection earlier than WEC
(ii) Potential for on-farm testing | Can odour be used to determine infection levels?
(i) Cost and time to train canines or development of artificial nose? | Research |
|
| Animal behaviour | Phenotypic, global positioning systems (GPS) to detect reduced movement found in resistant animals compared to susceptible. | (i) Potential for on-farm testing
(ii) Noninvasive | (i) Cost of technology
(ii) Indirect measure | Research |
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| Weight loss | Phenotypic, performance based marker which involves calculation of body weight gain based on food efficiency rates. | (i) Potential for on-farm testing
(ii) Non-invasive | (i) Cost of technology
(ii) Indirect measure | Research
HappyFactor |
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| Worm burden | Phenotypic, measuring the number of GIN parasites in the stomach at post mortem. | (i) Distinguish nematode species
(ii) Direct measurement of burden (includes exsheathed L3, L4 and adult GIN parasites) | (i) Measurement is terminal
(ii) Time consuming
(iii) Impractical | Research |
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| Worm weight | Phenotypic, weight of the total amount of GIN parasites collected at post mortem. | Direct measurement of burden (less intensive than counting worm numbers) | (i) Measurement is terminal
(ii) Time consuming
(iii) Impractical | Research |
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