Sheep and Goat Mortality Surveillance Project 2015 to 2018
The Sheep and Goat Mortality Surveillance Project finished after three years on 30 June 2018.
It has provided a useful sample of sheep and goat diseases in Victorian flocks and herds that showed the annual cycle of disease events as they change in line with the management calendar, along with the differences between good (2016) and poor (2017 to 2018) seasons.
When the results are viewed in conjunction with its predecessor project (the Lamb and Kid Mortality Surveillance Project 2009 to 2015) and parallel Sentinel Flock Project (2009 to 2012) the three have given a valuable description of the diseases that occur frequently and sometimes occasionally in Victorian sheep flocks and goat herds.
As such, they allow monitoring of disease trends to look for the unusual or unexpected and underpin the ‘proof-of-freedom’ from Emergency Animal Disease claims that Victoria and Australia make. All three projects were co-sponsored by the Sheep and Goat Compensation Fund.
No matter the time of year, or the seasonal conditions, worms (internal parasites) are the major disease recorded (see Figure 4). Worm control on Victorian sheep and goat farms remains problematic, through the poor adoption of control programs and the increasing occurrence of drench resistance.
No matter the time of year, or the seasonal conditions — worms (intestinal parasites) are the major disease recorded.
Worms have been seen as the major production limiting disease of sheep and goats — producers should implement ‘best-practice’ control programs. For more advice, discuss a program with your private veterinarian, or farm consultant, or visit paraboss.
Another constant is the occurrence of plant poisonings, particularly seen in weaner sheep in summer and autumn. Grazing heliotrope causes damage that doesn’t show up until later in life, and the effects of phalaris toxicity are either seen immediately sheep are introduced to green plants in the autumn (such as in autumn 2017), or later in the year when the chronic brain changes manifest themselves as staggery sheep.
There were a spate of cases of chronic copper toxicity cases, often associated with the feeding of pellets designed for cattle to sheep. Sheep can only tolerate a much lower level of copper in their diet than is needed by cattle — they can do so for several weeks, but not for months on end.
Copper toxicity in sheep is more common in Victoria than copper deficiency due to overzealous use of copper supplements. Always check that your feed supplier is incorporating copper at the correct (lower) level if feeding pellets to sheep.
Feeding concentrates (such as grains or pellets) in arrangements such as stock containment areas over summer and autumn is good practice but is not without its issues.
Acidosis is the most common disease seen and occurs when sheep are fed too much too soon, before their rumen has a chance to adapt to the high level of carbohydrate present in concentrate feeds. Slowly does it is always the mantra, and when changing diets or components.
These high carbohydrate diets also make for perfect conditions for pulpy kidney and can reduce the production of vitamin B1 in the rumen sufficiently to induce polioencephalomalacia. Always vaccinate sheep against pulpy kidney at least twice before introduction to grain feeding and give a booster on introduction.
Acidosis is the most common disease seen and occurs when sheep are fed too much too soon.
The metabolic diseases of hypocalcaemia and pregnancy toxaemia continue to be reported. The latter occurs around lambing time when ewes are (commonly) underfed, as in ‘twin-lamb’ disease.
Producers are becoming better at supplying appropriate levels of nutrition to ewes and does; for more information visit lifetime wool or enrol in a lifetime ewe management course near you.
Although lambing time is the commonest time to see hypocalcaemia, it does occur in all classes of sheep whenever they are stressed, particularly coming off lush green feed. Thus, we see cases in transported sheep, and in instances where sheep are yarded and held for, say, shearing.
Cereal grains are low in calcium, so it is imperative that limestone is included in rations whenever grain feeding to reduce the incidence of hypocalcaemia in the future.
Now that these free surveillance programs have wound up, producers with unusual or unexplained disease events in their flock can still access subsidised investigations through their private veterinarian, under the Significant Disease Program (which is also sponsored by the Sheep and Goat Compensation Fund).
For more information, contact your private veterinarian or local Agriculture Victoria animal health staff..
If you suspect an Emergency Animal Disease (EAD), you must report it.