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FAMACHA© vs PRODUCTION : What Is The Score? FAMACHA© vs PRODUCTION : What Is The Score? Department of Veterinary Tropical Diseases University of Pretoria,

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Presentation on theme: "FAMACHA© vs PRODUCTION : What Is The Score? FAMACHA© vs PRODUCTION : What Is The Score? Department of Veterinary Tropical Diseases University of Pretoria,"— Presentation transcript:

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2 FAMACHA© vs PRODUCTION : What Is The Score? FAMACHA© vs PRODUCTION : What Is The Score? Department of Veterinary Tropical Diseases University of Pretoria, South Africa Department of Veterinary Tropical Diseases University of Pretoria, South Africa J.A. van Wyk

3 Can farmer live with Targeted Selective Treatment ?

4 WILL THERE BE PRODUCTION LOSSES, & IF SO, ARE THEY RECONCILABLE WITH PROFITABLE FARMING ENTERPRISE ?

5 YES losses to be expected (Van Wyk & Bath 2002) For Targeted Selective Treatment FAMACHA © Body Condition Scoring Dag Score, or whatever… BUT Degree of challenge pivotal; and Total effect on production to determine outcome

6 HOWEVER, many factors can play a role Such as : Worm species Age, class, breed of host Susceptibility of worm population Level of worm challenge Level Of FAMACHA © application

7 Level of FAMACHA © application Frequency of examination of herd (the more frequent, the safer) Proportion of animals examined FAMACHA © categories treated Fixed In relation to worm challenge

8 Level of FAMACHA © application : Ours relatively “harsh” Mostly fixed FAMACHA © category (not adjusted according to mounting anaemia) Often too infrequent Ignored faecal egg counts Thus animals seriously challenged

9 Production trials 1. Farm 1 Trial 1: Replacement rams + wether tracers Trial 2: Replacement ewes 2. Farm 2 Trial 3: Replacement ewes However, various problems with trial design

10 Problems with trial design (MONEY, MONEY, MONEY) Nutrition more important than worms No two pastures identical (esp. if large), e.g. Nutrition (type and stance of herbage) Worm infection Host grazing habits Host susceptibility Slope Therefore several replicates essential Almost always small Therefore few animals per paddock Need many paddocks

11 SOUTH AFRICA : 15 % of land arable (only 15 % of which good arable) Natural pasture very variable (grass, small bushes, shrubs, trees) Acute funding problem “Fortunately” some farmers desperate due to drug resistance

12 TRIAL DESIGN “Side-stepped” problems (partially) –Single, quite large flock (> 150) –Common pasture for different trial treatment groups

13 Disadvantages of design Treatments affect one another “Excessive” contamination on one hand “Depletion” of L3 on the other Only suppressive vs selective treatment feasible (no “conventional” treatment groups, due to contamination by other groups)

14 Production trials 1. Farm 1 Trial 1: Replacement rams + wether tracers Trial 2: Replacement ewes 2. Farm 2 Trial 3: Replacement ewes

15 Farm 1 (Experiment 1 & 2) Pasture –Mostly natural grassland + little improved (kikuyu) –Generally reasonably flat –Rotational grazing (± too short for much worm control) –All flocks on farm share same pastures in rotation Sheep –Stud Merino –±1500 on farm –30 inches rain p/a (summer, ± well distributed) Worm species –H. contortus predom. (+ Trich.& Ost. problems autumn) –Fasciola hepatica a problem periodically Drug resistance (± relief from artificial dilution)

16 Experiment 1 - Highest individual faecal egg counts of the FAMACHA©-treated sheep DATE Sheep (n) in high egg count ranges TOTAL > > Dec 12 Jan 23 Jan 29 Jan 19 Feb TOTAL

17 DATEMEAN WORM EGG COUNT PER GROUP GROUP DOSING PARTICULARS * FAMACHASUPPRESSIVEGROUPINTER- VAL (d) 07 Nov 17 Nov 27 Nov 8 Dec 18 Dec 12 Jan 29 Jan 19 Feb 12 Mar 22 Mar 3 Apr 23 Apr 14 May 4 Jun 27 Jun Both (7 Nov) - Suppr (30 Nov) - Suppr (18 Dec) Suppr (8 Jan) Suppr (19 Jan)** Suppr (19 Feb) Both (8 Mar) - Both (9 Apr) - Both (4 Jun) - n/a Exp. 1: Mean faecal worm egg counts per group of sheep, plus dates on which all groups were drenched * Shifted to the closest date on which egg counts were done ** Only half of the suppressive group treated

18 Farm 1 (Experiment 1) NOTE: Experiment was “stopped” at the peak of the worm season, by drenching all the animals in both groups when worm challenge was excessively severe

19 Experiment 1 - Body mass

20 Experiment 1 - Highest individual faecal egg counts of the FAMACHA©-treated sheep DATE Sheep (n) in high egg count ranges TOTAL > > Dec 12 Jan 23 Jan 29 Jan 19 Feb TOTAL

21 Experiment 1 : Body Condition Score

22 Exp. 1 FAMACHA© score

23 DATEMEAN F.E.C. PER GROUP FAMACHA © SUPPRESSIVE 07 Nov 17 Nov 27 Nov 8 Dec 18 Dec 12 Jan 29 Jan 19 Feb 12 Mar 22 Mar 3 Apr 23 Apr 14 May 4 Jun 27 Jun Exp. 1: Mean FECs per trial group

24 Production trials 1. Farm 1 Trial 1: Replacement rams + wether tracers Trial 2: Replacement ewes 2. Farm 2 Trial 3: Replacement ewes

25 Farm 1 (Experiment 1 & 2) pasture –Mostly natural grassland + little improved (kikuyu) –Generally reasonably flat –Rotational grazing (± too short for worm control) Sheep –Stud Merino only –±1500 on farm –30 inches rain p/a (summer, ± well distributed) Worm species –H. contortus predom. (+ Trich.& Ost. problems autumn) Drug resistance (± relief from artificial dilution)

26 Worm egg countSheep n% > < Exp. 2: FECs - “FAMACHA©-treated sheep

27 DATE MEAN FAECAL EGG COUNTS FAMACHA©SUPPRESSIVE 11 Nov 7 Jan 17 Jan 3 Febr 8 Febr 9 Apr 25 Apr Exp. 2: Mean FECs

28 Farm 1 (Experiment 2) NOTE: Experiment was “stopped” at the peak of the worm season, by drenching all the animals in both groups when worm challenge was excessively severe

29 Exp. 2 - Mean FAMACHA© score

30 Exp. 2 - Mean live mass

31 Remember : SUPPRESSIVE versus SELECTIVE treatment

32 Exp. 2 - Mean Body Condition Score

33 Comment: Why did FAMACHA © “flock” & “monitor” groups differ so after all had been treated, while design was similar for both groups (only anaemic sheep drenched beforehand)

34 Production trials 1. Farm 1 Trial 1: Replacement rams + wether tracers Trial 2: Replacement ewes 2. Farm 2 Trial 3: Replacement ewes

35 Farm 2 (Experiment 3) pasture –Only natural grassland –Generally reasonably flat –Rotational grazing (± too short for much effect on worm) –All flocks on farm share same pastures in rotation Sheep –Commercial Merino only –±1200 on farm –20 inches rain p/a (summer, more erratic than farm 1) Worm species –H. contortus practically only roundworm –Fasciola hepatica a problem periodically No appreciable drug resistance

36 DATEMEAN FAECAL EGG COUNTS FAMACHA © SUPPRESSIVE 10 Jan 27 Febr 10 Apr 15 May Exp. 3: Mean faecal egg counts of “FAMACHA©” & “SUPPRESSIVE” groups (n = 48/group)

37 EGGS/ g FAECES SHEEP ( n ) > Maximu m fec (10 Jan): epg Exp. 3: Largest individual faecal egg counts (Jan. & Feb.) – Eggs per gram of faeces

38 Farm 2 (Experiment 3) NOTE: Experiment not “stopped” at the peak of the worm season, by drenching all the animals in both groups at the peak of the worm challenge

39 Exp. 3 - Mean live mass

40 Comment: Note initial difference between trial groups after randomisation by farmer as the sheep passed through the race

41 Exp. 3 - Mean Body Condition Score

42 Exp. 3 - Mean FAMACHA© score

43 But the trials are flawed! But the trials are flawed! So what!

44 Criticism of trials “Farmer” trials (e.g. timing, randomisation) [but: carefully done (e.g. BLUP Farm 1) Suppressively-treated sheep remove L3 & challenged L3 [but: pastures used optimally & shared other flocks] Not possible to test conventional control systems

45 TREAT-AND-MOVE TO SAFE PASTURE RR – 0,01% SR/RS – 10% SS – 90% PASTURE 1 PASTURE 2 * RR – 100% * Frequency of the allele R on pasture 2 is 100% No refugia

46 MOVE-AND-TREAT ON NEW PASTURE RR – 0,01% SR/RS – 10% SS – 90% PASTURE 1 PASTURE 2 * Frequency of allele R on pasture 2 is 0,01% * RR – 0,01% SR/RS – 10% SS – 90% REFUGIA (Molento, Van Wyk & Coles, 2004) (Molento, Van Wyk & Coles, 2004)

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