Barkly beef
Northern Territory. Department of Primary Industry and Fisheries
Barkly Beef; E-Journals; PublicationNT; Barkly Beef
2014-12-01
Made available via the Publications (Legal Deposit) Act 2004 (NT).; This publication contains many links to external sites. These external sites may no longer be active.
English
Agriculture; Tennant Creek Region; Periodicals
Northern Territory Government
Tennant Creek
Barkly Beef
Newsletter, Decenber 2014
application/pdf
1325-9539
Attribution International 4.0 (CC BY 4.0)
Northern Territory Government
https://creativecommons.org/licenses/by/4.0
https://hdl.handle.net/10070/253924
https://hdl.handle.net/10070/534650
DEPARTMENT OF PRIMARY INDUSTRY AND FISHERIES BARKLY BEEF | page 7 www.dpif.nt.gov.au on thirteen properties in the NT, it was found that 63% of animals had been infected with BVD by the time they were 3 years old. In some areas, around Alice Springs and the Stuart Plateau, it was found that 90%+ of the heifers had been infected with the virus before they were 2 years of age and thus vaccination against BVDV would be unnecessary in these mobs.(Schatz, Melville and Davis 2008) In herds with high numbers of non-immune animals, the introduction of Bovine Pestivirus can result in massive losses through abortion storms, where a high proportion of breeding cows will abort their pregnancies Abortions will flow on to cause increased out-of-season calves as the cows become pregnant later than normal. In herds with high levels of persistent infection, it is estimated that annual losses of up to 7% of calves can occur What can you do about Bovine Pestivirus? 1. Do nothing and accept current losses or the risk of abortion storms 2. Vaccinate all heifers prior to joining (immunity lasts 12 months): o This protects the heifers during their first pregnancy, during which time they should be exposed to the virus and develop their own natural immunity which is lifelong o This should be sufficient for properties with high levels of infection o A course of two vaccinations 4 weeks to 6 months apart is required o Immunity does not develop until after the second dose is administered o The second dose must occur 4 weeks prior to joining begins o The current cost of vaccination is approximately $5 per dose and can be purchased over the counter. 3. Vaccinate heifers as above and continue to administer annual vaccination to entire breeding herd: o May be necessary for properties with low levels of underlying infection where heifers may not be exposed to the virus naturally and develop their own immunity during their first pregnancy o Provides ongoing insurance against an abortion storm 4. Autovaccination program using PI animals: o Identify PI animals through blood or ear notch testing o Lock heifers with PI animals at a rate of 3-4% in close contact for 24-48 hours hours Note;- Once any control protocol is commenced it must not suddenly be terminated as this would leave the entire herd in a naive state and open for an abortion storm. Bovine Ephemeral Fever (3 Day Sickness):- Bovine Ephemeral Fever is another important viral disease affecting productivity in Northern Australia. It is an endemic disease affecting cattle across Darwin and the Katherine regions as well as the Barkly Tableland. Biting midges (Culicoides spp.) and some species of mosquitoes transmit it. These insects are most active in summer and autumn months and are much more prevalent when there has been an extensive wet. This generally determines the prevalence of the disease. The disease conditions show up as a fever and lameness lasting for about 3 days (3-day sickness), however recovery even after lengthy periods of up to three weeks recumbency has been recorded. Death is from exposure and dehydration. When the affected animal becomes recumbent in extreme environmental conditions it is essential to provide water, food and shade.