Good animal health management contributes to improved biosecurity that benefits the wider community. Animal Health investment also responds to the community’s high and increasing expectations of the red meat industry regarding the way livestock are treated.
The main opportunities to further increase animal health and welfare in Australian livestock relate to the management, reduction and treatment of endemic and exotic diseases, pests (parasites and invasive species), maintaining vigilant biosecurity practices to safeguard the future of the industry and pain management to mitigate the impact of husbandry procedures.
Chemicals used for Parasite Control in Ruminants
Macrocyclic Lactones (ML's)
ML's or "Mectin's" (ivermectin,abamectin,moxidectin,doramectin) are broad spectrum compunds that control a wide range of endo & ectoparasites including roundworms, mites, ticks & flies. They are not active on fluke's or tapeworms. The compounds interrupt nerve signals so that the parasites become paralysed.
The benzimidazoles (albendazole,oxfendazole & fenbendazole) are commonly known as "white drenches". They are active against a wide range of roundworms and can eliminate tapeworm segments (without killing the head), but have no activity against ectoparasites. Some are active on flukes. Parasites die from disruption to their cells nutrition, division & development.
This range is known as "clear drenches". Levamisole is active against a range of roundworms, but does not do a good job of penetrating the gut wall of infected animals to kill the larvae. It has no activity against flukes, tapeworms or ectoparasites. Parasites become paralysed as the compound generates continuous muscle contractions.
This has excellent activity against tapeworms (including the head), but controls nothing else. It produces paralysis of the worms by interfering with muscle activity.
Is active against blood feeding helminth's (barbers pole worm, liver fluke), but little else. It interferes with the energy metabolism of the parasite.
Is a narrow spectrum compound that kills only liver fluke. It kills the fluke by interfering with the enzymes required for energy production.
Rotation of Chemicals
The slow rotation of chemicals (every 1-2 years) is a strategy employed to minimise the onset of chemical resistance in parasites. There is generally some level of cross-resistance between members of a chemical class, so for the rotation strategy to work, it ie essential that the rotation includes compounds from different chemical classes rather than different members of the same class.