It may be just a small saliva sample on a cotton roll, but the CARLA test is offering a powerful tool for deer farmers in the parasite management space.
CARLA, which stands for carbohydrate larval antigen, is the first tool available to deer breeders which allows selection for favourable immune responses to gastrointestinal parasites and lungworm - two of the biggest disease challenges in yearling deer.
AgResearch Farm Systems Scientist Jamie Ward presented his final research findings on the test at the 2020 Deer Industry New Zealand Conference in June. He noted that the testing offered a way to do things differently in the parasite control space, all while incorporating animal welfare benefits and increased production gains for farmers.
He said the antigen is a positive trait with no downside and all upside. To have the science prove it and be confident was a good step for the industry.
A breeding value for the test has been made available so breeders or farmers can use the information to make selections or buying decisions. Ward hopes that over time, active animal selection for higher CARLA estimated breeding values (EBVs) will provide opportunity to reduce the reliance on drench, particularly when used in conjunction with other management practices for parasite control.
Shifting to herds of deer with higher genetic merit for the antigen will increase the resilience of deer farm systems by producing animals that are more resistant to parasite challenges.
A reduction in drench reliance could have positive flow-on effects into the marketplace, where consumers indicated a preference for ‘low chemical input’ products.
“It’s good to have this to demonstrate the industry is serious about addressing issues that could arise or already do arise in the marketplace.”
Ward said animals that are more genetically resistant to parasites helped offer some peace of mind if mistakes were made with parasite management on-farm.
“If someone forgets to drench for a week then you are not going to end up with a whole lot of weaners really sick with lungworm because someone made an error.”
CARLA has a heritability of 0.45, meaning that good genetic progress can be made if selected for. No adverse effects on other estimated breeding values (EBVs) were observed and testing costs $10 per animal.
Ward encourages breeders and farmers to consider including the test in their breeding objectives or breeding plans as it offers a way to genetically increase the parasite resistance of their animals.
He said it was not a silver bullet to stop drenching tomorrow, but farmers can positively change their herd to reduce drenching requirements over time.