Parasite tolerance very close
Geraldine deer farmer Chris Orange thinks he will take a punt on incomplete research into natural deer resistance to internal parasites.
The past chairman of the New Zealand Deer Farmers Association (NZDFA) is willing to try parasite resilient sires in his deer herd next year, although he will be monitoring the progeny closely.
‘‘If the research is sound, being able to breed for resilience in the herd will be a breakthrough for the deer industry, ‘‘ he said.
‘‘We won’t have to rely on drenching, which is costly and often comes with a 90-day standdown period before the animals can be sent to market.’’
Research by AgResearch to find out whether - or how- resistance is linked to growth rate and parasite levels in deer won’t be completed until late next year.
Resistance levels are scored using a saliva test that measures the antibodies triggered when animals ingest internal parasites.
Dubbed CARLA, short for carbohydrate larval antigens, the test was developed by AgResearch scientists for the sheep industry where CARLA breeding values (BV’s) are now a routine part of genetic selection.
AgResearch senior scientist Geoff Asher says there is considerable commercial pressure to come up with a practical solution to the growing resistance of internal parasites to the drenches used in deer.
‘‘When farmers are using the recommended deer drenching programme there is a 90 day withholding period between the last drench and slaughter.
‘‘That is a long time without a drench when you are chasing premium spring venison prices.
‘‘Some breeders want to get in on the ground floor and breed deer that need less drenching in their first year.
‘‘The ideal would be an animal that only needed drenching at weaning and perhaps once or twice more, before natural resistance to parasites kicks in.
‘‘As I say that’s the idea but we can’t promise that at least not yet. And the last thing we want to do is over-promise and under-deliver.’’
Research to date shows that CARLA responses in deer are heritable and that CARLA levels may be a useful predictor of resistance to internal parasites.
This resistance varies both within and across breeds with wapiti-crossbred (terminal) and red (maternal) progeny having similar responses.
Manager of Deer Select Sharon McIntyre said CARLA BV’s will eventually be provided within Deer Select. Deer Select is the New Zealand’s national deer recording database.
It stores pedigree and performance records, then uses this data to provide estimated breeding values and economic indices.
The research now underway into the linkage between CARLA scores and deer growth rates is part of a two-year project dubbed Tomorrows Deer.
‘‘We are looking at the health and performance response to an artificial Johnes’ Disease challenge in deer from both high and low CARLA bloodlines and those that come from Johnes resistant and susceptible bloodlines, ‘‘ McIntyre said
Orange said that even though deer are similar to sheep and cattle, deer are more difficult to test for parasites.
‘‘With sheep and cattle, you can do a faecal egg count. With deer, it is a test of the saliva.
‘‘It’s taken seven to 10 years for the research on CARLA to get to this stage where this can be tested.
‘‘It’s up to the breeders as to whether they want to take a punt on the research or not and try parasite resistant sires.’’