Using genetics to enhance farm resilience

A new season of ram sales is upon us which provides an opportunity to re-evaluate our breeding objectives. A huge amount of work has been done over the decades by ram breeders up and down the country to produce genetic lines with all manner of attributes, from fibre diameter and growth rate to disease resilience and parasite resistance.
Wednesday, 20 November 2019

A recent farmer survey showed that two of the top concerns farmers have regarding livestock health are drench resistant parasites and facial eczema. For both of these, genetics can play a part in a wider management plan to reduce their impact on farm.

Facial eczema is caused by a toxin released from the spores of a fungus found in pasture. The toxin is released in the rumen where it rapidly enters the bloodstream and causes damage to the liver. Sustained liver damage can lead to ill-thrift, poor reproductive performance, severe sensitivity to sunlight, and death. Some breeders have, through testing and selective breeding, produced rams with an increased tolerance to the fungal toxin. Introducing these genetics to your breeding flock can help safeguard future generations of sheep.

Drench resistance in parasites is a growing issue in NZ. A heavy reliance on drenches as opposed to other methods of managing parasites has led us to a situation where all three of the traditional drench families (levamisole, benzimidadoles, and macrocyclic lactones) are failing to some degree. Similar to other diseases sheep have degree of natural immunity to internal parasites, and selectively breeding for those with stronger immunity has allowed some breeders to develop flocks with significant resistance to internal parasites.

Biosecurity  keeping our livestock protected from disease  is critical for maintaining productivity and animal welfare. Breeding livestock that are inherently capable of withstanding disease challenge is a powerful tool for enhancing the resilience of our livestock farming systems.