Sheep Diseases

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The Dorper are not susceptible to fly strike and fleece rot. They have a high degree of disease resistance, and the red Maasai sheep have a high tolerance/resistance to intestinal worms. Other than that several diseases in Kenya/East Africa affect sheep. To prevent the worst ones, please consult below vaccination chart and your local veterinarian. The local veterinary officers will know which diseases you should vaccinate for in your particular area.  Some of the most common disease and pest challenges are as follows:

  • Orf 
  • Bluetongue 
  • PPR (pest of small ruminants) came to Kenya in 2006 and is related to rinderpest and very deadly
  • Sheep and Goat pox
  • Enterotoxemia 
  • Tetanus 
  • Brucellosis 
  • Worms 
  • Ticks and mites – transmit diseases and weaken the animals, so should be kept below critical levels of infestation at all times

Sheep Vaccinations

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It is recommended that ewes be vaccinated during late pregnancy for the colostridial diseases that most commonly affect sheep and lambs: clostridium perfringins type C & D (overeating disease) and tetanus. Clostridial diseases are caused by gram positive bacteria that are commonly present in the environment.By vaccinating the pregnant ewe, the lambs will acquire passive immunity when they drink the colostrum, the first milk produced by the ewe after lambing. In fact, a pre-lambing vaccination is the only way to protect lambs against type C and provide protection for early docking and castration, though anti-toxins can be administered to provide immediate, short-term immunity.

AgeVaccinate againstApplicationRemarks
2 weeks and above PPR (Peste des Petits Ruminants) Goat plagueS/C Properly done once in a lifetime will do.
Newborns should be vaccinated as a routine
Came to Kenya in 2006 – related to rinderpest.
If no vaccination the disease can kill all your goats and sheep.
2 weeks and aboveSheep and Goat pox S/C Annual vaccinationsIf no vaccination this disease may kill lambs and kids. In serious cases mortality may be high. 
2 weeks and above Enterotoxemia + tetanusS/C Every 6-8 months. Disease is common with lush pasturesPregnant animals should be vaccinated at least a month before giving birth.
Vaccination for tetanus should always follow tail docking
1 month and above Orf Scarification method.
If there is a risk of outbreak or
In endemic areas routine vaccination is recommended
Orf may be more common in goats due to their feeding habits as browsers of thorny bushes. Mortality of young can be high.
Repeat vaccination should be done 2-3 months after the initial one. 
The vaccine is live and can affect people, so HANDLE WITH CARE.
 Brucellosis Vaccine not available in East Africa in 2010.
1 month and aboveBlue tongueYearly vaccination of sheep with a live attenuated vaccine containing six strains of Bluetongue virus.available from KEVEVAPI, Nairobi 

Sheep Gestation

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A ewe is pregnant for 142 to 152 days, approximately five months or slighter shorter. Since ewes gestate for only five months, it is possible for them to lamb more often than once per year. While annual lambing is most common, lambing intervals of 8 months are realistic, especially in the tropics and with breeds that are less seasonal in their breeding habits.

Ewes: First-time moms

Though it depends upon breed, nutrition, and management, ewes can become mothers by the time they reach their first year. This is okay if the ewe lamb has achieved approximately two-thirds of her mature size (weight) before being bred. Thus, for some producers, it is commonplace to breed well-grown ewe lambs when they are 7 to 9 months of age. Other producers wait until their ewes are 18 months old before breeding them to lamb as 2 year olds. Different breeds of sheep reach puberty (sexually maturity) at different ages. 

Extra food

During her last month of pregnancy, a ewe needs extra nutrition because her lambs are growing rapidly inside of her and her mammary (udder) tissue is developing. Approximately 70 percent of fetal growth occurs during the last month of pregnancy. The growth of the fetuses also reduces the ewe’s rumen capacity.  Because of that in ewes ketosis could occur in the last part of pregnancy. A pregnant ewe requires a more-nutrient dense diet, especially if she is carrying multiple fetuses.

If a ewe doesn’t get enough feed during late pregnancy, she may get sick because her unborn lambs are taking most of her nutrients. Thin and fat ewes and ewes carrying multiple fetuses are most prone to pregnancy toxemia (ketosis). Thus, it is common to feed some grain or other energy-rich feed during late gestation. On the other hand, if a ewe is fed to rich diet during during larger part of the pregnancy, she may have trouble delivering her lambs because they may get too big to fit through her pelvic cavity. Fat ewes are also more prone to having problems at lambing time.

Green Gram Information Source Links

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  • AIC (2002). Field Crops Technical Handbook.
  • Adamu, R. S., Dike, M. C., Akpa, A. D. (2001). Insect fauna associated with green gram (Vigna radiata (L.) Wilc.) in the Northern Guinea Savanna of Nigeria. Journal of Sustainable Agriculture and the Environment, (Vol. 3) (No. 2) 331-336.
  • CAB International (2005). Crop Protection Compendium, 2005 edition. Wallingford, UK www.cabi.org
  • From ECHO’s seedbank. Green Gram or Mung Bean (Vigna radiata). By Bob Hargrave, ECHO Staff. www.echonet.org Available here: download
  • Insect Pest Management in Moong. Integrated Pest Management.
  • JNKVV, Madhya Pradesh, India: Diseases of green grams.
  • Kenya Agricultural Research Institute. KARI. Improved Green Gram Production. www.kalro.org
  • National Research Council. 2006. Lost Crops of Africa: Volume II: Vegetables. Washington, DC: The National Academies Press.  Available online: www.nap.edu
  • Nutrition Data www.nutritiondata.com.
  • Post harvest profile of green gram. Government of India, Ministry of Agriculture (Department of Agriculture and Cooperation) Directorate of Marketing and inspection. Branch Head Office. Nagpur – 440001. MRPC-76. www.agmarknet.nic.in
  • Publications and Fact Sheets on Mungbean. AVRDC Extension Materials. www.avrdc.org

Green Gram Mungbean Yellow Mosaic Virus

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Adults of Bemisia tabaci (Rhynchota: Aleyrodidae)
(c) Stephen Ausmus, 2008, USDA

MYMV causes serious loss in pulse crops such as beans, pigeonpea, mungbean and soybean. It is transmitted by whiteflies (Bemisia tabaci).

Symptoms: initially mild scattered yellow spots appear on young leaves. The spots gradually increase in size and ultimately some leaves turn completely yellow. Infected leaves also show necrotic symptoms. Diseased plants are stunted, mature late and produce very few flowers and pods. Pods of infected plants are reduced in size and turn yellow in colour.

The virus is not seed transmitted in mungbean or soybean.

What to do:

  • Plant tolerant/resistant varieties where available
  • Plant early and weed properly.
  • Control the vector (whiteflies).

Green Gram Rust

(Uromyces phaseoli)

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Rust on lower leaf surface of French beans. Symptoms are similar on green grams.
(c) A. M. Varela, icipe

The disease appears as circular reddish brown pustules (blisters) which appear more commonly on the underside of the leaves, less abundant on pods and sparingly on stems. When leaves are severely infected, both the surfaces are fully covered by rust pustules. Shrivelling of pods is followed by defoliation resulting in yield losses. Long distance spread of rust is by wind. Plant to plant spread is by farm tools, and moving bodies within the crop.

What to do:

  • Plant resistant varieties, if available.
  • Avoid continuous cropping with legumes.
  • Practise crop rotation with non-legumes such as cereals.

Green Gram Storage Pests

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Bean bruchid (Acanthoscelides obtectus) on soybean. Adults are 3-4.5 mm long, grey-brown.
(c) Clemson University – USDA Cooperative Extension Slide Series, Bugwood.org

The pod weevil (Piezotrachelus varius or Apion varium). Its a common pest of cowpeas in West Africa. Generally 13-26% of the pods are damaged. Losses of seeds up to 92% have been reported in Nigeria. The shiny black weevils bore holes in fresh green cowpea pods and lay eggs into the pods. The grubs feed on the seeds and pupate within the pods.

What to do:

  • Ensure grains are dried to 12% moisture content prior to storage
  • Use improved storage structures

Cabbage/Kales Brassicas Information Source Links

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  • AVRDC Training Center: Cabbage www.avrdc.org
  • CAB International (2005). Crop Protection Compendium, 2005 edition. Wallingford, UK www.cabi.org
  • Dobson, H., Cooper, J., Manyangarirwa, W., Karuma, J., Chiimba, W. (2002). Integrated Vegetable Pest Management. Natural Resources Institute, University of Greenwich, UK. ISBN: 0-85954-536-9
  • East African Seed Co. Ltd. Africa’s Best Grower^s Guide www.easeed.com 
  • Nega, E., Ulrich, R. Werner, S. und Jahn, M. (2003). Hot water treatment of vegetable seed – an alternative seed treatment method to control seed borne pathogens in organic farming. Journal of Plant Diseases and Protection 110(3):. 220-234. www.orgprints.org
  • Nutrition Data www.nutritiondata.com. 
  • OISAT: Organisation for Non-Chemical Pest Management in the Tropics www.oisat.org 
  • Varela, A.M., Seif, A. A., Lohr, B. (2003). A Guide to IPM in Brassicas Production in Eastern and Southern Africa. ICIPE Science Press, Nairobi. ISBN: 92 9064 148 7.