1. Genetic parameters involving subjective Famacha© scores and faecal worm egg counts on two farms in the Mediterranean region of South Africa S.W.P. Cloete, Z. Mpetile & K. Dzama Elsenburg and Stellenbosch University

2. Introduction
Drenches as the first line of defense of gastro-intestinal parasites has become unsustainable
Host resistance important component in almost all integrated pest management (IPM) programmes
Selection for low faecal worm egg counts (FWEC) benefited host resistance to gastro-intestinal helminths
Selection reduced the contamination of pastures by worm eggs
Resulted in less drenching and economic gains
FWEC routinely recorded in many formal evaluation schemes

3. Introduction
FWEC may not always reflect the parasite burden of animals
Infrastructure to conduct FWEC not always available or affordable:
Rural areas
Developing countries
Need alternative strategies
FAMACHA© system proposed as an alternative
Involves subjective scores of the conjunctivae of the eye of sheep with high burdens of haemotophageous nematodes
Allows sheep farmers to treat specific sheep, in contrast to treating all sheep present

4. FAMACHA© scoring system

5. Introduction
Principle not applicable when non-haemotophageous nematodes form the bulk of the gastro-intestinal parasite challenge
Eye scores supplemented with condition scores and dag scores
Scores were practical for commercial and resource-poor communal farmers in South Africa
Also applied elsewhere in the world
Not assessed under Mediterranean conditions, where species such as Teladorsagia, Trichostrongylus and Nematodirus predominate
FAMACHA© scores and FWEC thus assessed on two properties in the Mediterranean region of South Africa

6. Locations Elsenburg: North of Stellenbosch
Dryland lucerne and kikuyu pastures, oat fodder crops
Occasionally irrigated lucerne and kikuyu pastures
Rainfall 625 mm per annum mostly from April – September (78%)
Lambs born in March – April, tested in November
Tygerhoek:
Near Riviersonderend
Dryland lucerne pastures and oat fodder crops
Rainfall of 425 mm per annum mostly from April – September (62%)
Lambs born in March – April, tested in August of the next year

7. Material and Methods (Animals and records)
Data:
Elsenburg (1701 – 1815 Dormer and SA Mutton Merino lambs born from 2007 – 2014)
Tygerhoek (1531 – Merino hoggets born from 2006 – 2012)
Traits recorded and measured:
Subjective:
Nasal discharge (excluded, little variation)
Eye score
Body condition on two sites:
Midrib
Loin
Dags
Objective:
FWEC, counted at a sensitivity of 100 eggs/gram wet faeces
Skewed, transformed to natural logs + 100

8. Statistical Analysis
Data analysed with 5-trait threshold-normal animal models with animal as single random effect
Fixed effects:
Contemporary group (birth year x breed or selection line x sex)
Age of dam (2 – 6+ years)
Birth type (single or multiple)
Data were analysed by THRGIBB1SF90 software, Post Gibbs analysis with POSTGIBBSF90
Single chains of cycles were run
First cycles used as the burn-in period
Every 10th subsequent sample stored to derive posterior means, posterior standard deviations and 95% highest posterior density (HPD) confidence intervals

9. Results – Samples for dag score at Elsenburg

10. Posterior distributions for additive effects at Elsenburg

11. Descriptive statistics – Elsenburg
Trait
Number
Mean ± SD
Range
Eye score
1815
1.94 ± 0.89
1 – 4
Fat score rib
3.27 ± 0.73
1 – 5
Fat score rump
3.09 ± 0.73
Dag score
1813
2.08 ± 1.14
FWEC
1701
6.86 ± 1.24
4.6 – 10.4

12. Descriptive statistics – Tygerhoek
Trait
Number
Mean ± SD
Range
Eye score
2093
1.56 ± 0.59
1 – 4
Fat score rib
1531
3.07 ± 0.55
1 – 5
Fat score rump
1533
2.92 ± 0.67
Dag score
2207
2.17 ± 1.13
FWEC
2219
5.65 ± 1.09
4.6 – 10.4

13. Results – Genetic parameters at Elsenburg
Phenotypic variance (σ2p), heritability (h2), genetic correlations (rG) and phenotypic correlations (rP)
Trait
Eye score
Fat rib
Fat rump
Dag score
FWEC
²P
0.237
0.383
0.394
1.612
1.077
h2 (in bold on diagonal), rG (above diagonal) and rE (below diagonal)
0.13±0.05
-0.45±0.22
-0.71±0.27
0.06±0.22
0.66±0.27
-0.43±0.06
0.12±0.04
0.92±0.23
0.12±0.18
-0.19±0.21
-0.44±0.06
0.66±0.07
0.17±0.05
0.04±0.18
-0.25±0.22
0.16±0.07
-0.17±0.06
-0.18±0.06
0.31±0.07
-0.19±0.23
-0.03±0.06
-0.10±0.05
-0.09±0.05

14. Results – Genetic parameters at Tygerhoek
Phenotypic variance (σ2p), heritability (h2), genetic correlations (rG) and phenotypic correlations (rP)
Trait
Eye score
Fat rib
Fat rump
Dag score
FWEC
²P
0.294
0.463
0.325
1.670
1.040
h2 (in bold on diagonal), rG (above diagonal) and rE (below diagonal)
0.12±0.05
-0.82±0.23
-0.50±0.18
0.25±0.22
-0.29±0.21
-0.26±0.07
0.38±0.13
0.80±0.18
-0.14±0.27
0.01±0.22
-0.26±0.06
0.65±0.06
0.30±0.11
-0.15±0.22
0.23±0.23
0.06±0.06
-0.10±0.06
-0.07±0.07
0.31±0.08
0.27±0.26
0.02±0.05
-0.10±0.05
-0.15±0.06
-0.07±0.06
0.14±0.05

15. Conclusions
All traits were heritable and variable and should respond to directed selection
Genetic correlations suggested that:
Animals with higher eye scores were leaner
Fat score on the rib and rump are largely similar traits
Eye score at Elsenburg were favourably correlated to FWEC
Dag score, although highly heritable, were not associated with any other trait
Favourable genetic correlation between eye score and FWEC possibly associated with nematode species distribution
Haemonchus more prevalent
Dag score of significance in controlling breech blowfly strike
The results support further studies on the FAMACHA© system under low-input small stock operations

17. Schalk Cloete Directorate Animal Sciences: Elsenburg 021 8085230