![]() ![]() Adult rabbits have an average life expectancy of two to five years. Once they reach adult weight their chances of survival are good. As kittens become older, their survival rate improves. Climatic factors, predators and diseases are the main causes of natural mortality. The mortality of kittens born late in the year may rise to nearly 100%, due mainly to lack of suitable feed. In many rabbit populations, the high reproductive rate can be offset by a 60-70% death rate amongst kittens up to a month old. Where favourable conditions for breeding persist, a single doe may produce up to 30 kittens in six or seven litters a year.įemale rabbits usually conceive their first litters shortly after the first autumn rain, thus ensuring the maximum numbers of litters are born while green feed is available. While breeding virtually ceases when pastures dry off, in the south-west, a small proportion of females can be pregnant in most months. Later, the pregnancy rate falls, as does the average litter size. The percentage of adult females that are pregnant rises steadily through the breeding season to nearly 100% in July and August. It is usually shorter in other areas of the State. The main breeding season of rabbits in the south-west extends from about May to November depending on availability of suitable green feed. Landholders are required to control rabbits on their properties. In WA, they are declared pests of agriculture in both their domestic and feral forms under the Biosecurity and Agriculture Management Act 2007. Rabbits have a well-documented history for causing severe environmental damage. Since the release of the Rabbit Haemorrhagic Disease Virus (RHDV) the estimate for agricultural production loss is approximately $206 million annually, with an additional $25 million spent annually on management and research costs. The accumulative benefit to Australia's pastoral industries of 60 years of myxoma and RHDV biocontrol is estimated at $70 billion. In 1996 rabbits were estimated to cost the nation at least $600 million annually in lost agricultural production. ![]() During this period they had a profound effect on Australia’s economy. ![]() Until the successful release of the myxoma virus, and the introduction of 1080 (sodium fluoroacetate) poisoning programs in the 1950s, rabbit numbers remained essentially unchecked. It was common practice for early mariners to leave live rabbits on small islands as a food supply in case of shipwreck or future visits. Rabbits were established on at least one island off the coast of Western Australia (WA) in 1827 and may have been present on other islands earlier than this. By the 1920s, rabbits had colonised most of the southern half of Australia and were present in extremely high numbers over most of that area. The majority of Australian rabbits are descended from 24 wild rabbits released near Geelong in 1859. European rabbits ( Oryctolagus cuniculus) originated in Spain but they are now found throughout most of the temperate regions of Europe, North Africa, Chile and Australasia. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |