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.

Wool clothes

Wool has all the right messages to appeal to discerning consumers. It is naturally sustainable, biode-gradable, resilient and improves indoor air quality through the absorption of harmful gases. Furthermore, it is non-allergenic, soft and natural, flame retardant, and offers an incredible range of colour and style opportunities.

Process for making wool clothes

Worsted yarn uses only the best fleece from the back of the sheep. It is the longest, strongest and richest in lanolin. The fibres are combed to lie flat and spun in "two ply’s" that when spun together creates a "3 diameter run" piece of yarn. It looks much neater and tighter on a spool than woollen yarn. Since worsted yarn’s fibres are fairly uniform in length there are no short pieces to fail or cause that scratchy feeling. It is considered a stronger fabric.

Woollen yarn on the other hand is spun from all the various lengths of wool fibres found on a sheep’s body, both long and short fibres from the sheep’s back, belly, bottom, legs etc. Since it is not combed to lie flat, woollen yarn has a fuzzy look because the shorter fibre ends stick out of the yarn imparting a dull appearance to the finished product. Clothes of woollen yarn will usually feel rougher or scratchier.

Types of wool yarns

Woollens: A general term describing various fabrics woven from woollen yarn. Woollen yarn is spun from the shorter wool fibres, which are not combed to lie flat as in worsted yarn. Soft surface textures and finishes are produced and the weave of individual yarns does not show as clearly as in worsted fabrics. Woollen fabrics include tweeds, fleeces and meltons.

Worsteds: A general term describing various fabrics woven from worsted yarns containing the longer fibres spun from combed wool. Only the prime, longer fleece is used to produce worsted fabrics. Worsted wool refers to tightly woven, smooth, clear finished goods in a variety of twill and other stronger weaves.

The wool for clothing is spun using the worsted process. It is spun into a single piece of yarn and then two pieces of yarn are twisted together making a 2 ply yarn strand. The 2 ply is then twisted together, making what is called 2/18 diameter yarn. Four pieces of yarn are then woven into the cloth.

Select for Desirable Wool Traits

How to Select for Desirable Wool Traits

•           Record grease fleece weight and staple length of each fleece at shearing.

•           If possible, obtain clean fleece weight.

•           Rank fleeces according to weight of fibre produced and staple length.

•           If possible, rank sheep within a given grade of wool, within a given age classification, and within a group in which the number of lambs raised is known.

For those times when feeling insignificant

Inspiration - Understanding our fears


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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.

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.

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..

Global Wool Week coming up!

The world is gearing up for another global wool week on 5th-12th October. The Prince of Wales’s Campaign for Wool will also introduce the first Canadian Wool Week from September 29 – October 5, in Toronto. (Find the Campaign for Wool link under Interesting Links.)

This campaign now includes representatives from the International Wool and Textile Organization, The British Wool Marketing Board, Australian Wool Innovation, the National Council of New Zealand Wool and runs in 12 countries including, France, Italy, Spain, Netherlands, Germany, Norway, Australia, China, Japan, Korea, the United States and now in Canada under the Prince’s Charities Canada.

Wool weeks are held in countries across the world during the autumn retail season. Featuring leading designers, retailers, celebrities - and lots of sheep - the Wool Weeks give hundreds of thousands of people the opportunity to get up close and personal with wool.

The Campaign for Wool has influenced a new demand for wool on an international scale, and its efforts have seen an outstanding threefold increase in the price farmers receive for their wool.

Open to the public from the 5th to 12th October, the Interiors Wool Collection offers free admission and all items displayed will be on sale at London's Southwark Cathedral during Wool Week.

The Scottish Shetland Wool Week takes place on 4-12 October.

UK 5 – 12th October

Germany 20th – 26th October

China 20th – 26th October

Belgium 21st – 31st October

Japan 27th Oct – 4th November

Netherlands 3rd – 9th November

Sadly no participating news from the South African wool industry at time of publishing.

Did Ewe Know? Sheep Breeds

Sheep Breeds

There are more breeds of sheep than breeds of any other livestock species. 

Worldwide, there are more than one thousand distinct sheep breeds. Sheep come in all different sizes, shapes, and colors. 

Breeds are usually classified according to their primary purpose (meat, milk, or wool), the type of fibers they grow (fine, medium, long or carpet wool; or hair), the color of their faces (black, white, red, or moddled), and/or by specific physical or production characteristics.

Did ewe know?

Sheep belong to the ruminant classification of animals. Ruminants are characterized by their "four" stomachs and "cud-chewing" behaviour. The cud is a food bolus that has been regurgitated. Sheep breeds There are more breeds of sheep than breeds of any other livestock species. Worldwide, there are more than one thousand distinct sheep breeds. Sheep come in all different sizes, shapes, and colours. Breeds are usually classified according to their primary purpose (meat, milk, or wool), the type of fibres they grow (fine, medium, long or carpet wool; or hair), the colour of their faces (black, white, red, or mottled), and/or by specific physical or production characteristics.

Sheep Improve plant biodiversity. Numerous studies have shown how sheep and goats, used under prescribed conditions, can help increase the plant biodiversity .When sheep are grazed in the same areas for several years, the level of perennial grasses within the plant community tends to increase which has been shown to increase water infiltration and decrease erosion. Sheep will graze for an average of seven hours per day, mostly in the hours around dawn and in the late afternoon, near sunset. When supplements are fed, it is best to feed them in the middle of the day so that normal grazing patterns are not disrupted.

Did ewe know sheep are intelligent? Sheep are above average in learning ability and have very strong herding instincts, making it hard to be separated from the flock Sheep have survived as a species when others have disappeared. The sheep has precisely the correct amount of intelligence it needs to allow it to function within the grazing/ruminating niche that it inhabits (Ruminants don't need to be Einstein). Therefore, when the question is examined as the amount of intelligence present relative to the amount needed, it would be unfair to characterize them as "dumb." The pejorative use of "dumb" or "stupid" as applied to sheep implies "dull," and sheep have too many interesting facets to their behaviour to deserve being labelled as dull. Sometimes the shepherd is tempted to call sheep stupid because the sheep do not react in the manner the shepherd thinks they should. However, sheep react in a very predictable manner, and the failure of the sheep to behave according to the shepherd's desires may, in fact, reflect the shepherd's lack of intelligence rather than the sheep's.

Eyes: Wide-angled Sight Did you ever look a sheep eye to eye? If you have you probably noticed a few things. For one thing, they have a very large pupil, and the sheep pupil is differently shaped than the human pupil. The sheep pupil is somewhat rectangular in shape. And the eyeball is placed more to the side of the head, which gives them a wider field of vision. Behavioural scientists believe that the placement and structure of the sheep's eyes are due to nature's designation of sheep as a prey species. Predator species, such as dogs and coyotes, have eyes placed toward the front of their head. This narrows their total field of vision but it increases their binocular visual field. This gives the predators better depth perception and a more concentrated field of vision.

Prey species, like sheep and cattle, have a much wider visual field. With only slight head movement, sheep can scan their entire surroundings.. They have wide-angled perception, allowing them to see behind them without turning their heads. If there is a threat, the sheep is likely to perceive it and the behavioural response is generally to flee. The shape of the pupil further enhances the ability of sheep to pick up movement. The rectangular shape provides a built-in wide angle lens effect which is further enhanced by the placement of the visual receptors in the retina. The total effect is enhanced peripheral vision. It is speculated that a certain amount of vertical vision is sacrificed, i.e., sheep may not be able to easily observe objects that are overhead, such as a predator in a tree.

Colour: What about colour vision? For many years it was believed that both cattle and sheep were colour blind, but apparently this is not true. Current evidence is that all common livestock have the cones necessary for colour vision. In addition, research with sheep trained to discriminate between colours has led investigators to conclude that sheep are not colour blind. It is, however, likely that sheep's colour acuity is not equal to other species, such as humans. They are above average in learning ability and have very strong herding instincts, making it hard to be separated from the flock. Their non-violent nature, however, does make them easy targets for predators ranging coyotes, bears, and mountain lions to eagles and neighbourhood dogs. In addition to fencing, many farmers protect their sheep with guard dogs, donkeys or llamas.

Ears: Hearing Did ewe know? Sheep become nervous and difficult to handle when stress hormones are elevated, so it may be useful to avoid loud or shrill noises when handling or moving sheep. The sheep can amplify and pinpoint sound with its ears. Sound arrives at each ear at slightly different times with a small difference in amplitude which the auditory system can process into a directional signal. This can be further refined by moving the ears, head or the entire body. This skill is probably almost as important as sight and smell for sheep.
#Sheep eyes, #Sheep ears #Sheep intelligent #Ruminants