Bluetongue “bloutong” - Treatment and prevention tiips

·         Bluetongue is  an acute, insect-borne viral disease of sheep caused by an orbivirus,  transmitted by Culicoides midges, otherwise known as “muggies”. There are 24 known serotypes of blue tongue virus, of which 21 occur in South Africa. Cattle, goats and wild ruminants are also susceptible but clinical blue tongue is seldom seen in these species. 

·         This is a seasonal disease normally occurring  from mid-Summer until the frost in autumn. 

·         Sheep infected with the bluetongue virus develop a very high temperature and a severe inflammation of the band above the hoof.

·         In addition, affected sheep may have severe ulcer-lesions, and may refuse to walk because the feet are very painful.

·         An early clinical sign is excessive salivation, which occurs 3 to 4 days after the onset of the disease.

·         Although the disease is not usually fatal in adult sheep, they may die from secondary infections like pneumonia.

·         Lambs are severely affected by the disease and heavy losses can occur.

 Treatment

The animal's mouth and tongue are usually so sore that it cannot eat, and its hoofs are too painful for it to go and seek food. The first line of treatment is therefore to enclose the sheep in a small camp where shade, green feed and water are close at hand. They must be handled as little as possible. Antipyretics and analgesics (for example, aspirin) may be administered.

·         Since the insect breeds in the mud along the edges of slow moving streams and dams, efforts should be made to eliminate these as breeding sites.

·         Ideally flocks should be bedded on high ground.

·         The flock should be inoculated approximately 9 weeks before the start of the breeding season. 

·         Note that pregnant ewes should never be inoculated especially within the first 60 days of gestation.

·         This could result in the abortion or malformation of the lambs..

·         Animals should therefore be inoculated with the three vaccines A, B and C at three-week intervals. 

·         Antibiotics can only prevent secondary infections and are used to salvage affected sheep.

·         Maternal antibodies will protect lambs against the virus for the first three months of life and they should not be inoculated at this time.

·         They should however be vaccinated after the three months have passed.

·         If one vaccinates the lambs of vaccinated ewes before 3 months, maternal immunity may interfere with the response of the young sheep to the vaccine.

Prevention The inoculant can be administered as soon as the ewes have dropped their lambs. Lambs receive passive immunity through the colostrum of their dams and should preferably not be inoculated against bluetongue before the age of six months. Rams should receive the last inoculant two months before the mating season. Otherwise they must be inoculated after this period. Ewes should receive the last inoculant no later than three weeks before the mating season. Pregnant ewes should not be vaccinated. Should there be an outbreak of bluetongue without the sheep having been inoculated; ewes that have been in lamb for at least three months can be inoculated with reasonable safety.

Rift Valley Fever (RVF)

RVF is a mosquito-borne zoonotic viral disease affecting many animals, especially domestic livestock, and humans. It is most common in eastern and southern Africa. Sheep, in particular exotic, introduced breeds, are most susceptible.

It can cause fever, haemorrhage and abortion in pregnant animals. More than 90% of infected lambs die; mortality of adult sheep is as low as 10%. Humans can contract RVF from mosquitoes and possibly other bloodsucking insects.

RVF epidemics have a serious impact on the economy due to death of livestock, infection of humans and bans on livestock trade from RVF-infected areas.

Rift Valley Fever  - symptoms and prevention

Is an infectious zoonotic disease affecting sheep, goats, and cattle.

Rift Valley Fever (infectious enzootic hepatitis) and humans are susceptible to the  disease.

Rift valley disease is a viral disease of sub-Saharan Africa. The virus attacks the liver and causes symptoms ranging from fevers and listlessness to hemorrhage and abortion rates approaching 100% in pregnant sheep. It is transmitted by mosquitos. RVF is a notifiable disease and it is thus important for farmers to inform the State Vet and Animal Health Technician when they suspect the disease.

Vaccination of animals against RVF has been used to prevent disease in endemic areas and to control epizootics. Rift Valley fever is more deadly than West Nile virus. Animals should be moving away from standing water and moved to higher altitude areas. Caution must be exercised when handling infected tissues by wearing gloves, masks, goggles and by using viricidal disinfectant. The incubation period is 1 – 3 days.

Symptoms in animals:

Abortions, mortalities in young animals, jaundice, lagging behind, weakness and exhaustion, bloody diarrhea, bleeding from the nose and fever.

Symptoms in humans:

Influenza-like symptoms – headaches, muscle pain, joint pain, abdominal pain and nausea.

Prevention

Vaccinate sheep older than 6 months. Inactivated vaccine can be used in pregnant ewes. Animals must be given a booster within 3-4 weeks after initial vaccinations and then must be done annually.

Movement restrictions are recommended. No movement without notifying the Provincial State Vet.The disease is caused by the Rift Valley Fever (RVF) virus, a member of the genus Phlebovirus in the family Bunyaviridae and the disease is transmitted by mosquitoes.Limited to Africa in earlier years, it causes the enormous waste of livestock, especially in wet conditions

For decades Rift Valley fever has caused the illness and death of large numbers of livestock in Kenya and in much of sub-Saharan Africa. Increasing evidence linking the disease to human deaths as well has led epidemiologists to include Rift Valley fever on the list of emerging viruses (including HIV and Ebola) that infect thousands of people each year.

Clinical Signs

In young lambs the incubation period varies from 20 to 72 hours. Some lambs die suddenly without showing signs of this disease. Usually, however, affected lambs develop fever, refuse food, physically weaken, recline and die after a course of 24 hours. Mortality often reaches 95%.

In adult sheep the most common clinical finding is abortion. Most affected sheep show fever of 41 to 42 °C, abortion and vomiting. During fever, severe leukopenia, especially of neutrophils, forms.                

Controlling RVF in animals

•           Outbreaks of RVF in animals can be prevented by a sustained programme of animal vaccination. Both modified live attenuated virus and inactivated virus vaccines have been developed for veterinary use. Only one dose of the live vaccine is required to provide long-term immunity but the vaccine that is currently in use may result in spontaneous abortion if given to pregnant animals. The inactivated virus vaccine does not have this side effect, but multiple doses are required in order to provide protection which may prove problematic in endemic areas.

•           Animal immunization must be implemented prior to an outbreak if an epizootic is to be prevented. Once an outbreak has occurred animal vaccination should NOT be implemented because there is a high risk of intensifying the outbreak. During mass animal vaccination campaigns, animal health workers may, inadvertently, transmit the virus through the use of multi-dose vials and the re-use of needles and syringes. If some of the animals in the herd are already infected and viraemic (although not yet displaying obvious signs of illness), the virus will be transmitted among the herd, and the outbreak will be amplified.

•           Restricting or banning the movement of livestock may be effective in slowing the expansion of the virus from infected to uninfected areas.

•           As outbreaks of RVF in animals precede human cases, the establishment of an active animal health surveillance system to detect new cases is essential in providing early warning for veterinary and human public health authorities.

RVF FORESCASTING AND CLIMATIC MODELS

Forecasting can predict climatic conditions that are frequently associated with an increased risk of outbreaks, and may improve disease control. In Africa, Saudi Arabia and Yemen RVF outbreaks are closely associated with periods of above-average rainfall. The response of vegetation to increased levels of rainfall can be easily measured and monitored by Remote Sensing Satellite Imagery. In addition RVF outbreaks in East Africa are closely associated with the heavy rainfall that occurs during the warm phase of the El Niño/Southern Oscillation (ENSO) phenomenon.

Age determination - cattle, sheep and goats

Sheep age 

You will not be able to determine the exact age of the animal from is teeth – there will be a few months either way. It is important not to confuse temporary teeth in a year old animal, which has not yet started teething, with an adult sheep that is 4 years of age (“full mouth”).  The more mature characteristics of the face will be helpful.

 Ageing is done according to the following formula for sheep (and goats):-

                        15 months (1 year)            ± 3 months                        =          2 TOOTH (2 permanent teeth)

24 months (2 years)           ± 3 months                        =          4 TOOTH

33 months (3 years)           ± 3 months                        =          6 TOOTH

42 months (4 years)           ± 3 months                        =          8 TOOTH (Full-mouth)(Volbek)

Gummer (Slytbek) (6-8 years)                                    =          Old, stumpy teeth (or very long teeth, if little wear   takes place)

Cattle age 

Correct way to check sheep and goats
The lifting of lips to expose the teeth should take place in such a way as to prevent unnecessary stress to the animal.  Use index and middle finger or thumb preferably.

South African Wool Market Strengthens

Port Elizabeth – The wool market was dearer at this week’s sale and the Cape Wools Merino indicator gained 2,1% to close at R113,45/kg (clean). This is 1,6% up compared to the opening sale of this season and 8,3% up compared to the corresponding sale of the previous season. On the Australian market, the indicator decreased by 3,1%. The Cape Wools All-Wool Indicator gained 1,7%.

Wool auctions resumed after the Easter recess and wool traders commented that the reduced wool supply would benefit growers offering better type wools. According to local traders the increase was supported by the weaker Rand and the continued firm demand from China for good quality long, well-grown Merino wool.

The Rand on the day traded 2,5% weaker at R12,08 against the US dollar, compared with last week’s average rate, and strengthened 1,6% against the Euro at R12,82. The offering comprised of 11 949 bales, of which 99% was sold. Major traders were G Modiano SA (3 887), Standard Wool SA (2 887), Lempriere SA (2 513) and Stucken & Co (1 088).

The weekly price monitor sample, limited to AWEX type MF5, 70-80mm, VM<=2% wool only,,75/kg, 18,5 microns strengthened by 2,2% to R121,91/kg, 19 microns gained 2,6% to close at R117,64/kg, 19,5 microns rose with 2,4% to close at R114,50/kg, 20 microns gained 2,7% to close at R113,21/kg, 20,5 microns increased with 2,3% to close at R112,02/kg, 21 microns gained 2,6% to close at R/kg, 21,5 microns were unchanged on R107,64/kg and 22 microns rose with 0,6% to close at R107,64/kg.

experienced an average price movement as follows: 18 microns were up by 3,9% to close at R125

The next sale is scheduled for 22 April where approximately 5 400 bales will be on offer.

Keep your clip clean

Wool can and should be marketed as a natural, environmentally-friendly quality fiber. Anything that undermines this image can lead to consumer resistance and have a negative effect on the marketability and price of wool.

Contamination of wool by foreign objects – like black hair, bale twine, wire, bolts, cigarette butts, matches, dog hair, pieces of cloth – pose a serious threat to the long-term sustainability and profitability of wooled sheep farming.

Contamination of wool can result in big claims against buyers or processors, and damages the reputation of the clip.

Hard objects in a bale can damage core sampling and wool processing machines, while deviating fibers (black hair, Kemp) can spoil meters of fabric as these only show up at the final stage of processing.

In addition, increasing worldwide antipathy towards any form of pollution, and stricter regulations, particularly by the European Union, about environmental pollution, are putting pressure on the wool industry to eliminate chemical contaminants and ensure that pesticide-free wool products reach the market.

The main sources of contamination are:

·           Foreign objects originating in the shearing shed, e.g. fertilizer bags, baling twine, pieces of metal, clothing, cigarette butts, etc.

·                     Wool packs containing loose material, usually fibers.

·                     Sheep branding inks and certain wound dressing containing discoloring compounds.

·                     Colored fiber resulting from crossbreeding or non-woolled sheep breeds running with Merino sheep.

·                     Residues from pesticides used for the treatment of external parasites on sheep

What producers should do to prevent contamination

 

In the shearing shed:

It is vitally important for all producers to maintain good management principles in the shearing shed to avoid contamination prior to classing and packing. No matter how well-classed the clip, if it is contaminated with baling twine or other foreign objects, the buyer will penalize it.

·                     Clean the shed thoroughly before shearing commences and store away any tools, bolts and other metal objects.

·                     In order to minimize possible contamination with animal hair, feathers, baling twine, etc., ensure that the holding pens are clean.

·                     Educate shearing team and workers about the dangers of contamination.

·                     Provide a rubbish bin with a lid for cigarette buts and other rubbish.

·                     Ensure that proper supervision is exercised during shearing.

·                     No dogs or other animals should be allowed in the shed.

·                     Use a rubber rake rather than an ordinary broom with hair in the shearing shed.

·                     Never use jute bags in the shearing shed, be it for wiping feet or sharpening the shears on.  Rather use carton, paper or a piece of sheepskin.

·                     Never use baling twine in the shearing shed, even for hanging tools or other gadgets against the wall.

·                     Make sure that shearers don’t use twine for their shears.

·                     Shearers should preferably not be allowed to sleep in the shearing shed.

·                     Always shear purebred woolled sheep first.

During shearing and classing: 

·                     Wool stained with branding ink, tar, urine, dung, blood, paints or discolored by fungi or chemicals must be removed before shearing, packed separately and marked as “Brands”

·                     Remove all bloodstained wool during the shearing process.

·                     Request the shearers to remove pieces of skin cut off during shearing. Skin pieces quickly become dry and hard and can damage carding machines.

·                     Topknots and cheek wool can contain hairy fibers and must, therefore, be packed with the lox, irrespective of how long and attractive they look.

·                     Colored fibers are often found around the horns and should not be packed with bellies or pieces to prevent contamination. 

Timetable - Cultivated pastures (South Africa)

Sheep on Lucerne - Skape op Lusern

Rooster - Aangeplante Weiding

Die koeie vreet mengsel van groen lusern, groen hawer/ryegrass, mieliemeel, sojaoliekoek, katoensaad en minerale. 57% kragvoer teenoor 43% ruvoer op DM basis bereken. - Gerdie Landman - Mooimelk Koeihotel, Kookhuis, Oos-Kaap.