Managing parasite burdens

Intestinal roundworms in grazing livestock production is a major concern in UK farming systems. Anthelmintic resistance is prevalent on many farms with some flocks now subjected to drench failure in three of the five chemical families available. However, parasite burdens can be effectively managed using good management strategies such as faecal egg counts (FEC) and Carbohydrate Larva Antigen (CARLA) Saliva Tests. Spring Rise offers a FEC service using the McMasters technique, developing technology such as the FECPAKG2 system and CARLA Saliva Test, all of which are convenient sources for testing internal parasitic burdens.

What is a Faecal Egg Count and IgA Saliva Testing?

FEC counts the number of worm eggs in faeces and is used to monitor the worm burden in sheep, goats, cattle and horses. The number of eggs present is an indication of the number of adult worms in the gut and results are presented as ‘eggs per gram’ (epg) of faeces. In addition to FEC, measuring the levels of mucosal IgA (an antibody specific to particular roundworm species) is an accurate indicator of resistance - sheep only. Spring Rise analyses FECs using the FECPAKG2 computerised system which provides FEC results quickly via email, thus enabling drenching decisions to be made in the field. Spring Rise also uses the McMasters Technique, a system whereby worm eggs are manually counted using a microscope, using specific calculations and decisions can also be made in the field. Another technique used by Spring Rise is known as CARLA Saliva Test which is a method of testing for parasite specific antibody levels in saliva as an indicator of worm resistance in sheep. Research indicates that measuring the levels of IgA (an antibody specific to particular roundworm species) in saliva provides an accurate indicator of resistance. For example, if an animal is producing higher levels of IgA it is likely to be shedding less worm eggs and is more resistant.

What are the Benefits of FECs and IgA Saliva Testing?

FECs and IgA Saliva results should not be used as ‘stand alone’ diagnostic tools and advice given from the veterinary surgeon should always be followed. This combined with observation and parasite management techniques provide valuable information for the control of parasites in the herd or flock. Spring Rise highlights three points that FECs help determine:

1 Monitoring the efficacy of your anthelmintics – resistance detection. Wormer resistance may be minimised by knowing the wormers that work on your farm and by monitoring their ongoing performance. Only treat animals that need it. The responsible use of wormers will assist in delaying the development of wormer resistance.

2 FECs provide information for monitoring pasture contamination – map your farm. Using FEC testing, the data can be matched with a map of the farm and determine were the high worm burdens exist. Once identified, worm burdens can be reduced using management methods such as resting the field and avoid grazing vulnerable stock.

3 IgA saliva tests can be used to genetically select animals to increase the animal’s resistance and resilience to worm challenges.

Take Home Message

Research shows that using diagnostic technologies, FEC, IgA Saliva Testing - breeding for worm resilient and resistant animals can reduce the use of anthelmintics by half and can be of financial benefit to the livestock enterprise.