Dairy goat farming in Australia: current challenges and future developments

Transcription

1 Dairy goat farming in Australia: current challenges and future developments Pietro Celi (DVM, PhD) & Peter White (BVSc, PhD) Faculty of Veterinary Science, University of Sydney 1

2 Feral Goats 2

3 Meat Goats 3

4 Mohair Goats 4

5 Cashmere Goats 5

6 Dairy Goats 6

7 The Dairy Goat Society of Australia GoatSocietyAustralia 7

8 Dairy goat breeds in British Alpines 13% Australian Melaan 6% Australia Australian Brown 1% Saanens 29% Toggenburgs 16% Anglo Nubians 35%

9 The Dairy Goat Society of Australia Type of enterprise Commerical Producer 9% Retired 7% not answered 10% Hobby 48% Serious/Show 26% 9

10 The Dairy Goat Society of Australia Gender of DGSA members Age not answered 6% Under 18 5% % not answered 23% Male 16% Over 65 21% % Couple 19% Female 42% % 10

11 Goat Health Issues Timing, extent and causes of on-farm goat mortalities Internal parasites Caprine arthritis encephalitis (CAE) Salmonellosis Caseous lymphadenitis (CLA) Johne s disease The impact of these or other conditions has not been qualified or quantified 11

12 CAE in Australia and Asia 12

13 Caprine Arthritis Encephalitis lentivirus (retroviridae) Pathogenesis virus multiplies in monocytes and macrophages more prevalent in dairy goats 13

14 Caprine Arthritis Encephalitis Arthritis hardening of udder chronic interstitial pneumonia chronic weight loss in adults and progressive rear limb paresis Leukoencephalomyelitis in young (2-6 months) 14

15 Caprine Arthritis Encephalitis transmitted by infected colostrum/milk kids should be removed from infected dams immediately after birth and fed heat treated colostrum and pasteurized milk or colostrum/milk from negative does horizontal transmission also occurs no vaccine no treatment 15

16 Caprine Arthritis Encephalitis Test and removal Goats are tested every six months and those testing positive are removed A positive serologic result indicates a goat is infected for life and a potential continual source for transmission of the virus 16

17 Caprine Arthritis Encephalitis Diagnosis clinical and serologic evaluation detection of CAEV antibodies using agar gel immunodiffusion test AGID, ELISA, IFA test 17

18 Caprine Arthritis Encephalitis CAE bulk milk diagnostic test sample is easy to obtain the test is reasonably cheap routine indicator of subclinical infection epidemiological studies genetic background of CAE Early monitoring and intervention 18

19 Intestinal Parasites 19

20 Intestinal Parasites 20

21 Parasite Resistance Increased numbers of parasites resistant to current drugs Documented problem in small ruminants Growing problem in horses and cattle No new anthelminthics on the horizon Management practices are more important than ever to reduce parasite loads 21

22 How wide spread is this problem? 22

23 Haemonchus contortus 8/24/2012 From material 1st Asian on Dairy Goat 23

24 Why H. contortus has become resistant so easily? Extremely large genetic pool containing naturally occurring resistance genes Ability of worm to survive In host - hypobiosis Out of host - resilience to weather Very high fecundity (lots of eggs) Frequent use of anthelmintic treatment 24

25 Frequent use of anthelmintics Traditional wisdom says treat everything on the farm and treat often We now see that this approach was short sighted and has ended up leaving us with no effective treatments For the most part no new drugs are in the pipeline > $200 million to develop a new drug 25

26 Practices that should be avoided Frequent treatment with anthelmintics Treating and moving to a clean pasture Under dosing Treating when minimal infective larva present Treating entire herd 26

27 New goals in parasite management Minimize drug use Use drugs therapeutically instead of for prophylaxis This requires us to monitor the animals in some fashion to identify animals in need of treatment Develop a strong refugia of sensitive worms to bred with the resistant 27

28 Selective treatment Research indicates that 20-30% of the animals in a herd may shed greater then 80% of the eggs By identifying and treating these animals we can decrease shedding of a large portion of the eggs and prevent the development of severe disease 28

29 Identify animals to treat Generally use one of several methods Quantitative fecal egg counts (FEC) Fecal consistency or Body condition score Poor choice for Haemonchus Identification of anemic animals Only used if Haemonchus is the primary worm of interest 29

30 Anthelmintic Use Goats metabolize anthelmintics faster than other species Bioavailability is lower and/or shorter than with other hosts Goats require 1.5 to 2 X dose compared to sheep or cattle to achieve a therapeutic dose Haemonchus contortus resistance to all 3 classes of anthelmintics 30

31 FAMACHA Developed in South Africa in response to the emergence of severe anthelmintic resistance A system to assess Haemonchus contortis (barber pole worm) infection in sheep and goats and the need for deworming individual animals Named for its originator: Dr. Francois Faffa MAlan CHArt

32 Alternative Therapies for GIP Copper Oxide Wire Particles (COWP) Condensed Tannins Fungi? Nutrition Vaccines Genetic improvement Famacha 32

33 Parasite vaccines Parasite Research None currently on the market Difficult to develop because of complex anatomy of parasites Close to developing a vaccine for malaria 33

34 Future Research Continued development and evaluation of alternative (non-chemical) parasite control technologies Integrate selective treatment (FAMACHA) with novel control methods (COWP, CT forages) for on-farm testing Development of EFFICIENT goat production systems 34

35 Research in Australia 1. Investigate the efficacy of registered anthelmintics used in combination against resistant gastrointestinal nematodes in goats 2. Assessment of the physical elements influencing the efficacy of orally administered anthelmintics in goats 3. Establish dosages, withholding periods and export slaughter intervals for all parasiticides registered for use on goats 35

36 Efficacy or registered drugs Anecdotal evidence suggests that those chemicals registered for use on goats are of limited usefulness due to a high degree of worm resistance, particularly among barber s pole worm (haemonchus) and black scour worm (Trichostrongylus spp.); however, little is known about the efficacy of these registered chemicals when administered as a combination drench or which combinations are the most effective 36

37 Efficacy or registered drugs Project Objectives Trial the four (4) drugs registered for use in goats (benzimidazole (BZ), levamisole (LEV), macrocyclic lactones (ML) and morantel (Mor)), in isolation and in combination, to establish: 1. The efficacy of each drug when used in isolation according to label instructions 2. The efficacy of all possible drench combinations when used against drench resistant isolates of barber s pole worm (haemonchus) and black scour worm (Trichostrongylus spp.). 3. The most effective treatment regime in general terms to control barber s pole worm (haemonchus) and black scour worm (Trichostrongylus spp.). 37

38 Factors influencing the efficacy of orally administered anthelmintics Other factors possibly influencing the efficacy of drenches include: Anecdotal evidence that closure of the oesophageal groove in goats, depending on the position of the goats head, results in variable dosage. A lack of understanding of the effect of curfewing goats prior to drenching (i.e. drenching on a full/empty stomach). 38

39 Factors influencing the efficacy of orally administered anthelmintics Project Objectives Establish the influence of curfew on the efficacy of anthelmintics administered as an oral drench in goats. Establish the influence of head position on the efficacy of anthelmintics administered as an oral drench in goats. Test the hypothesis that: The efficacy of sheep oral drenches can be optimised when used on goats by drenching at a dose rate 1.5 times that recommended for sheep. 39

40 Establish dosages, WHPs and ESIs Project Objectives 1. Develop a list of all chemicals and products currently registered for use in treating goats to manage internal and external parasites. 2. Establish dosages, WHPs and ESIs for these chemicals that will promote efficacy and satisfy importing country residue limit requirements 40

41 Conclusions Need R&D&E in dairy goats Need cheap and effective tools to diagnose diseases Need innovative and efficient systems to improve dairy goat production and health 41

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43 Joint ISNH/ISRP International 2014 Harnessing the Ecology and Physiology of Herbivores Save the date 8-12 September 2014 To register your expression of interest click on: 43