Endemic conditions affect productivity but relatively little information have been published in relation to effects of endemic conditions on-farm and at the abattoir. In order for producers to identify issues in their sheep and make informed decisions on management producers need feedback from abattoirs on what conditions are found in submitted stock and what the effect of the conditions are, both on farm and at abattoir. This study looked at seven conditions that were deemed important by the South Australian sheep industry based on effects seen through the production chain or due to being commonly identified at post mortem inspection at abattoir.
Small lungworm infections of sheep are often detected at post-mortem examinations and at abattoirs but thought unimportant because they cause few obvious clinical signs. However, heavy lungworm infections may cause production loss, either directly or by worsening other respiratory diseases, such as pneumonia. Thus suggesting that treatment or prevention may be warranted if prevalence is high. It is thought that anthelmintics have some effect, but largely strategies for the treatment and prevention of small lungworms have not been described in the Australian context. Two species of small lungworm occur in sheep in Australia, Muellerius capillaris and Protostongylus rufescens, which require a mollusc intermediate host to complete their lifecycle. This paper presents the effect of pasture molluscicide treatment on the prevalence and severity of small lungworm infections, and the productivity of lambs grazing improved pastures in southeast South Australia. The findings of the snail population, the lucerne pasture availability, small lungworm infection levels within lambs, and lamb growth rates will be presented.
The Faecal Egg Count Reduction Test (FECRT) has been the mainstay for diagnosing anthelmintic resistance (efficacy lower than 95%) in the past 40 years and recent refinements have made it cheaper and more convenient. The World Association for the Advancement of Veterinary Parasitology has re-defined the test to allow before and after testing (instead of an untreated control group) and ’90 eggs observed’ in the control count the new standard. Using more sensitive methods such as Mini-FLOTAC or FECPAKG2, or even repeated counts using a McMaster worm egg chamber, the starting worm count can confidently be lowered to 1-200 epg, as long as sufficient numbers of sheep are included in the test.
The efficacy of all single active products against Haemonchus and Teladorsagia is low enough to warrant always recommending using active ingredients in combination. This can be achieved by concurrent administration or by using formulated combination products, but not by mixing products unless specifically allowed on the label. Long-acting single-active treatments such as moxidectin injectable need to be ‘primed’ with an effective drench.
Trichostrongylus continues to show susceptibility to the macrocyclic lactones, but BZs and levamisole have low efficacy. Nematodirus spp. eggs have shown up in groups of sheep treated with BZs , an indication of emerging resistance to this active ingredient.