चरने वाले पशुओं में आंतरिक परजीवी संक्रमण का प्रबंधन

India, a developing country is a land of villages and more than 60 % of the human population still depends upon agriculture and livestock sector for their livelihood. According to 20^th livestock census of India, the total Livestock population is 535.78 million with the total Bovine population is 302.79 million and most of the rural livestock population is still reared on grazing based system. As the grazing animals are always exposed to parasites in the open fields, the chances of reinfections are constant in livestock following chain reactions mode. The parasitic diseases directly cause severe economic losses on the livestock industry by affecting the health, weight gain, feed conversion efficiency, reproduction and also the treatment expenses of farm animals.

When grazing animals ingest larvae from pasture at the start of the season worm infestation begins. Calves are highly susceptible to worms making them the common culprit in taking a low-level presence of worms into a full-blown infestation. Infected calves cultivate huge larvae populations within their gut and then shed worm eggs onto the pasture for other animals to ingest. The lifecycle of a parasite from egg stage to egg-producing larvae stage is around five weeks.

To prevent a long-lasting load that would affect the production and health of the herd, it is important to be aware of the symptoms and indicators of worms in cattle.

SIGNS OF WORMS IN CATTLE

Observe an animal by looking for the visible symptoms of worms, which can include:

• Listless appearance and loss of appetite.
• Watery and profuse diarrhoea
• Sudden weight loss and emaciation
• Poor coat condition
• Pale mucous membranes
• Laboured, open mouth breathing
• Pot-belly appearance of abdomen in calves
• In case of heamoprotozoa, bi-phasic or tri-phasic pattern of fever, enlargement of Cutaneous lymph nodes, haemoglobinuria, etc

The most reliable way to check for parasite infection in cattle is with a fecal egg count test.

Even though the Anti-parasitic drugs are effective to minimize the internal parasites, it does not provide a long-term solution in grazing animals. Few anti-parasitic drugs like benzimidazole, levamisole and ivermectin have already developed resistance by the parasites. Hence, a combined approach is required for the control internal parasites to achieve the ideal productivity in grazing systems.

Animal sheds and Housing management

The animals having good living conditions resist or tolerate better against internal parasites as compared to animals kept under poor housing conditions.

• Animal sheds must be well ventilated and lighted to maintain required humidity and air circulation as high humidity and low light causes enhanced growth of parasites population.
• Always keep optimum number of animals in the shed as overstocking causes large population to have parasites at a time.
• The animal should not be fed on the ground. Use Feeders which cannot get contaminated with feces/dung.
• Water should be clean and free from faecal matter and watering areas should be well drained with gravel or even cemented floors. Animals must be prevented from the access to parasite infected water bodies.
• Proper drainage facilities in the shed reduce the chances of survival of the parasites.
• The newly introduced animals should be quarantined for 4–6 weeks and if required administer the anti-parasitic drugs.
• Always keep the manure by making heap so that eggs, larvae, cyst, or other stages of parasites are killed due to heat generated during composting.
• The bedding material should be allowed to decompose along with manure for better control of parasites as it acts as important source of various parasitic infection.
• Application of nitrogen fertilizers like urea (1:25) to the surface of manure also eliminate the parasites.

Nutritional management

• Types of diet and availability of vitamins, minerals and other nutrients are directly related with susceptibility of animal to the parasites.
• Vitamin A, D and B complexes are essential in developing the immunity against parasites. Minerals like zinc, iron, cobalt, sodium, potassium, phosphorus, etc. are very essential for proper functioning of immunological phenomenon going inside the animal’s body to develop functional immunity against the parasites.
• Animals on low protein diets are more susceptible to infection because they produce less immunoglobulin IgA. Hence, provide the balanced ration along with mineral mixture supplementation.

Grazing by age group:

As susceptibility of animals against parasites varies with age, it is reasonable to graze different age group animals in different fields.

Multispecies grazing:

There are numerous other benefits to multi-species grazing. Each species has different grazing behaviour that complements one another. For example, sheep prefer to eat weeds, short tender grasses and clover, while cattle prefer to eat taller grasses thus allowing the sun light to reach the ground to kill many parasites.

Zero grazing:

Zero grazing means keeping the animal in captivity to reduce the parasitic load. During confinement the animal should be fed off the ground in feeders and watering containers should be kept free from faecal matter.

Alternative forages:

The pasture plants containing condensed tannins have anthelmintic properties. Forage plant species containing high levels of condensed tannins include sericea lespedeza (warm season legume), birds foot trefoil (perennial legume) and chicory (leafy perennial). Tropical legumes contain more condensed tannins than temperate legumes. Normally trees and shrubs contain higher levels of tannins than pasture grasses.

Genetics of animals:

Genetics is probably the best long-term weapon against internal parasites in animals. Some animal breeds are more resistant and resilient to internal parasites. On the basis of faecal egg output a parasite resistant or susceptible breed can be identified. Following molecular test, the parasite resistant gene can be identified and by animal cloning or by selective breeding a parasite resistant breed of animal can be created.

Biological control:

The natural plough, ‘earthworm’ can ingest worm eggs and larvae during its normal feeding process thus destroying the egg in the gut or carrying them below the soil surface. Dung beetles ingest manure, thus killing eggs and larvae of various parasites. The fungus Duddingtonia flagrans is relatively easy to culture and can be released in the environment against the targeted parasites in a controlled fashion.

Anti-parasitic drugs management strategies:

 Anti-parasitic drugs are still an important part of parasite control in the grazing livestock. As per Indian climatic conditions the grazing animals must be dosed at least twice in year at the onset (May end) and offset of monsoon (September end). However, strategic use of anti-parasitic drugs is necessary to ensure effectiveness of treatment and to slow down the rate of drug resistance development.

• Incorporate worming regimes with seasonal changes to ensure treatment is hitting the larvae at the right stage.
• Larvae can often survive on pasture throughout the winter causing a problem for the following season’s grazing animals.
• Combine treatment with changes in location. Move animals out of pasture known to be infected with larvae. A move to clean pastures is the best way to ensure the cycle does not begin again.
• Rotate deworming agents to avoid the likelihood of parasites becoming immune to a particular product.
• The best strategy for maintaining herd health is to be able to quickly recognise the signs of worms in cattle and know when to start treatment.
• Use of alternative dewormers which are having anthelmintics properties and can be used as an alternative to chemical control of parasites. Such products include herbal dewormers, charcoal and diatomaceous earth. By taking experts advise, copper oxide particles, garlic, wormwood, wild ginger or snakeroot, goosefoot, conifers, mustard and castor oil, squash or pumpkin seeds; carrot and fennel seeds; pyrethrum etc. can also be successfully used to eliminate the internal parasites.

Authors:

Priyanka M. Kittur^1*, Apeksha Ukey¹, Anish Koul² and Yallappa M. Somagond³

¹Research Scholar, Animal Physiology Division, ICAR-National Dairy Research Institute, Karnal-132001

²V.Sc Scholar, Animal Physiology Division, ICAR-National Dairy Research Institute, Karnal-132001

³Scientist, Animal Physiology Division, ICAR-National Research Centre on Mithun, Medziphema, Nagaland- 797106

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