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.

SA Wool season finished on a high note

Port Elizabeth – The wool market maintained its recent gains and the Cape Wools Merino indicator gained a marginal 0,9% to close at R141,20/kg (clean). This is 26,5% higher compared to the opening sale of this season. In the Australian market, the indicator increased by 2,0%. The Cape Wools All-Wool Indicator gained 0,9%.

Local traders commented that on the day finer wool ended slightly dearer and coarser wool slightly easier, but all in all a wonderful close to a successful season. The Cape Wools Merino indicator is at an all-time high and expectations are that the market will maintain its positive momentum at current levels going into the new season.

The Rand on the day traded 0,7% weaker at R12,33 against the US dollar, compared with last week’s average rate, and weakened 2,0% against the Euro at R13,89. The offering comprised of 10 369 bales, of which 98% was sold. Major traders were Lempriere SA (4 004), Standard Wool SA (3 737) and G Modiano SA (1 716).

The weekly price monitor sample, limited to AWEX type MF5, 70-80mm, VM<=2% wool only, experienced an average price movement as follows: 18 microns were up by 1,7% to close at R152,38/kg, 18,5 microns were unchanged at R147,46/kg, 19 microns gained 3,2% to close at R146,90/kg, 19,5 microns rose with 1,8% to close at R145,07/kg, 20 microns lost 0,4% to close at R140,57/kg, 20,5 microns increased with 1,9% to close at R140,47/kg, 21 microns gained 2,1% to close at R139,32/kg, 21,5 microns strengthened by 1,9% to R137,27/kg and 22 microns rose with 0,5% to close at R135,76/kg.

The first sale of the new season is scheduled for 12 August.

Coefficient of Variation (CV)

A range of fiber diameters occurs within each wool sample.  A wool sample may therefore have a mean fiber diameter of 19 µ, yet the fibers within the sample may vary from 7 µ to 37 µ.

Two criteria are used to measure the distribution, namely CV and standard deviation (SD).  CV is a function of SD, as SD is used in the formula to calculate CV.

CV (%) = Standard deviation * 100

                     Mean fiber diameter

Strong demand drives SA Wool market to new Record High

Port Elizabeth – Strong demand and a persistently weak Rand drove wool prices to a record high and the Cape Wools Merino indicator gained 4,7% to close at R140,00/kg (clean). 

This is 25,4% higher compared to the opening sale of this season and up 27,9% compared to the corresponding sale of the previous season. In the Australian market, the indicator increased by 5,0%. The Cape Wools All-Wool Indicator gained 4,6%.

Buyers reported a strong demand for and a shortage of good quality Merino wool on the day and commented on the low levels of the stockholding further along the wool processing pipeline. Seasonal supply concerns also impacted by production showing little evidence of recovery. The weaker Rand played its part in driving market prices to these new record levels.

The Rand on the day traded 1,4% weaker at R12,24 against the US dollar, compared with last

week’s average rate, and weakened 3,7% against the Euro at R13,62. The offering comprised of 6 751 bales, of which 99% was sold. Major traders were Standard Wool SA (3 354), Lempriere SA (1 476) and G Modiano SA (1 466).

The weekly price monitor sample, limited to AWEX type MF5, 70-80mm, VM<=2% wool only, experienced an average price movement as follows: 18 microns were up by 5,4% to close at R149,82/kg, 18,5 microns strengthened by 4,6% to R147,45/kg, 19 microns gained 4,3% to close at R142,30/kg, 19,5 microns rose with 5,6% to close at R142,49/kg, 20 microns gained 7,0% to close at R141,11/kg, 20,5 microns increased with 4,8% to close at R137,91/kg, 21 microns gained 4,4% to close at R136,41/kg, 21,5 microns strengthened by 4,4% to R134,70/kg and 22 microns rose by 10,1% to close at R135,04/kg.

The last sale of the season is scheduled for 10 June where approximately 10 200 bales will be on offer.

Sterk vraag dryf SA Wolmark tot Rekordvlak

Port Elizabeth – Sterk aanvraag en ‘n swak geldeenheid dryf wolpryse tot nuwe rekord hoogtes en die Cape Wools Merino-aanwyser het met 4,7% gestyg en op R140,00/kg (skoon) gesluit. Dit is 25,4% hoër as op die openingsveiling en 27,9% hoër teenoor die ooreenstemmende verkope van die vorige seisoen. Op die Australiese mark het die aanwyser met 5,0% gestyg. Die Cape Wools Alle Wol aanwyser styg met 4,6%.

Kopers het genoem dat daar ‘n sterk vraag na en ‘n tekort aan goeie gehalte Merinowol op die dag was en het kommentaar gelewer oor die lae vlakke wolvoorraad verder af in die wol verwerkings pyplyn. Seisoenale produksievlakke het ook ‘n impak op pryse gehad met produksie wat min bewys van herstel toon. Die swakker Rand het ook sy rol gepeel om markpryse tot hierdie rekordvlakke te dryf.

Die Rand teen R12,24 was sowat 1,4% swakker teenoor die Amerikaanse dollar vergeleke met die vorige week se veiling en teen R13,62, sowat 3,7% swakker teenoor die Euro.

ʼn Verkoopspersentasie van 99% is bereik van die 6 751 bale wat op die veiling aangebied was. Die grootste kopers op die veiling was Standard Wool SA (3 354), Lempriere SA (1 476) en G Modiano SA (1 466).

Die weeklikse prysmandjie, beperk tot AWEX tipe MF5, 70-80mm, VM<=2% wol alleenlik, se gemiddelde prysbeweging was as volg: 18 mikron styg met 5,4% tot R149,82/kg, 18,5 mikron versterk met 4,6% tot R147,45/kg, 19 mikron versterk met 4,3% tot R142,30/kg, 19,5 mikron versterk met 5,6% tot R142,49/kg, 20 mikron styg met 7,0% en sluit op R141,11/kg, 20,5 mikron styg met 4,8% en sluit op R137,91/kg, 21 mikron versterk met 4,4% en sluit op R136,41/kg, 21,5 mikron versterk met 4,4% en sluit op R134,70/kg en 22 mikron styg met 10,1% tot R135,04/kg.

Die volgende veiling is geskeduleer vir 10 Junie wanneer sowat 10 200 bale aangebied sal word.

SA Wool prices at record high!

Port Elizabeth – Exceptional demand at the recent sale resulted in a new record high in wool prices and the Cape Wools Merino indicator gained 8,5% to close at R132,02/kg (clean). This is 18,3% higher compared to the opening sale of this season and 13,4% higher compared to the corresponding sale of the previous season. In the Australian market, the indicator increased by 7,6%. The Cape Wools All-Wool Indicator gained 10,2%.

Limited supply of long, good quality Merino wool and strong demand from the Chinese and Indian markets drove wool prices to the record high. Local traders noted that some clients

are resisting higher price levels.

The Rand on the day traded 0,8% weaker at R11,94 against the US dollar, compared with last week’s average rate, and weakened 3,3% against the Euro at R13,46. The offering comprised of 8 829 bales, of which 99% was sold. Major traders were Standard Wool SA (2 968), G Modiano SA (2 386) and Lempriere SA (2 270).

The weekly price monitor sample, limited to AWEX type MF5, 70-80mm, VM<=2% wool only, experienced an average price movement as follows: 18

microns were up by 7,5% to close at R140,66/kg, 18,5 microns strengthened by 6,2% to R138,96/kg, 19 microns gained 10,7% to close at R137,94/kg, 19,5 microns rose with 9,0% to close at R134,64/kg, 20 microns gained 8,0% to close at R132,46/kg, 20,5 microns increased with 9,2% to close at R130,37/kg, 21 microns gained 7,9% to close at R130,02/kg, 21,5 microns strengthened by 9,3% to R128,28/kg and 22 microns rose with 5,8% to close at R122,98/kg.

The next sale is scheduled for 27 May where approximately 8 000 bales will be on offer..

SA Wolpryse styg tot rekordvlak!

Port Elizabeth – ‘n Besondere sterk vraag na Merinowol het pryse tot ’n rekordvlak laat styg en die Cape Wools Merino-aanwyser het met 8,5% gestyg en op R132,02/kg (skoon) gesluit. Dit is 18,3% hoër as op die openingsveiling en 13,4% hoër teenoor die ooreenstemmende verkope van die vorige seisoen. Op die Australiese mark het die aanwyser met 7,6% gestyg. Die Cape Wools Alle Wol aanwyser styg met 10,2%.

‘n Beperkte voorraad lang goeie gehalte Merinowol en sterk vraag vanuit China sowel as Indië het wolpryse opwaarts gedryf. Plaaslike handelaars het opgemerk dat sommige kliënte weerstand bied teen die hoë prysvlakke.

Die Rand teen R11,94 was sowat 0,8% swakker teenoor die Amerikaanse dollar vergeleke met die vorige week se veiling en teen R13,46, sowat 3,3% swakker teenoor die Euro. ʼn Verkoopspersentasie van 99% is bereik van die 8 829 bale wat op die veiling aangebied was. Die grootste kopers op die veiling was Standard Wool SA (2 968), G Modiano SA (2 386) en Lempriere SA (2 270).

Die weeklikse prysmandjie, beperk tot AWEX tipe MF5, 70-80mm, VM<=2% wol alleenlik, se gemiddelde prysbeweging was as volg: 18 mikron styg met 7,5% tot R140,66/kg, 18,5 mikron versterk met 6,2% tot R138,96/kg, 19 mikron versterk met 10,7% tot R137,94/kg, 19,5 mikron versterk met 9,0% tot R134,64/kg, 20 mikron styg met 8,0% en sluit op R132,46/kg, 20,5 mikron styg met 9,2% en sluit op R130,37/kg, 21 mikron versterk met 7,9% en sluit op R130,02/kg, 21,5 mikron versterk met 9,3% en sluit op R128,28/kg en 22 mikron styg met 5,8% tot R122,98/kg.

Die volgende veiling is geskeduleer vir 27 Mei wanneer sowat 8 000 bale aangebied sal word.

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.