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Dealing with a threat
A KEY challenge for policymakers interested in poverty alleviation is the identification and promotion of broad-based income opportunities that may lead to well-being. Such possibilities are, unfortunately, limited.
The livestock sector appears to present an opportunity to enhance the livelihood of a good proportion of the world’s poor. According to a recent report quoted by a spokesperson for the World Health Organization, livestock ownership currently supports and sustains the livelihood of an estimated 675 million people in developing countries. These people fully or partially depend on livestock for income and subsistence.
Livestock can provide a steady stream of food and revenue, help raise farm productivity and are often the only livelihood option available to the landless as they allow the exploitation of common-property resources for private gain. In addition, at the smallholder level, livestock are often the only means of asset accumulation and risk diversification which can prevent a slide into poverty involving people residing in marginalized areas.
Recent statistics reveal that an estimated 70 per cent of the poor people are women for whom livestock represent one of the most important assets and sources of income. Livestock ownership also tends to increase consumption of animal products and to create employment opportunities. In spite of the trend towards increasing scales of production and vertical integration, the greater part of the foods, both plant and animal, consumed in developing countries like Pakistan is produced by semi-subsistent farmers.
Livestock production is the world’s largest utilizer of land, either directly through grazing or indirectly as the source of fodder and feed grains. Globally, livestock production currently accounts for some 40 per cent of the gross value of agricultural production. In Pakistan, it accounts for about one-third of agricultural production.
This share, however, is rising quickly following rapid increases in livestock production as a result of population growth, urbanization, changes in lifestyles and dietary habits and increasing disposable incomes. This is reflected in the fact that growth in the livestock sector has consistently exceeded that of the crop sector.
Pakistan’s economy has undergone considerable diversification over the years, yet the agricultural sector is still the largest and livestock represent an important sub-sector, which accounts for 49.1 per cent of agricultural value added and about 11.4 per cent of the GDP.
The importance of livestock in rural economy may be understood from the fact that 30 to 35 million people are engaged in livestock raising, having household holdings of 2 to 3 cattle/buffalo and 5 to 6 sheep/goat per family which help them derive 30 to 40 per cent of their income. The livestock include buffaloes, sheep, goats, camels, horses, asses and mules. Sheep and goats which are known as small ruminants have pertinent position in the livestock sector as their population has doubled in the last 15 years.
Sheep and goats are raised for profit as mutton, wool and/or dairy. Any reduction in these results in a loss to the producers and to the livestock economy.
The productive and reproductive potential of domesticated livestock is adversely affected by clinical and subclinical diseases. Among the various infectious diseases, parasitic diseases are economically significant as most of them are subclinical.
Parasites are organisms that derive nourishment and protection from other living organisms which are known as hosts. Helminths are one of the major types of parasites which infect domestic animals and also man.
Of various species of helminths, the members of class nematoda are important vis-a-vis animals. The nematodes residing in gastrointestinal tract (GIT) are of particular concern.
Although, there are a large number of species of nematode parasites which dwell in the GIT, but Haemonchus contortus, Ostertagia ostertagi and Trichostrongylus colubriformis are particularly notorious owing to impaired productivity of small ruminants. Thus, parasites negatively affect the economy of the livestock industry.
Gastrointestinal nematodes adversely affect the productivity of small ruminants. The adverse effects of nematodes include haematological and biochemical alterations, loss of appetite, loss of body weight, decrease in protein, impaired digestive efficiency which can lead to loss of meat (27 per cent) and wool (40 per cent), poor reproductive performance, retarded growth and even death among sheep/goat.
Economic losses due to low productivity worth Rs19.68 million in sheep and 11.74million in goats due to Haemonchus contortus alone have been estimated in Faisalabad. The affliction is caused by a blood-sucking nematode of the stomach.
Conventionally control of gastrointestinal nematodes in sheep relies heavily on anthelmintic (drugs against helminths) treatment of the flocks. The chemical control of nematodes has become increasingly difficult as a consequence of the appearance of nematode populations with resistance to commonly used anthelmintics.
Resistance is considered to have been established when previously effective drugs stop to kill exposed parasitic population at the therapeutically recommended dosages. The existence of anthelmintic resistance came to light in the mid-1950s as a result of the failure of phenothiazine to control haemonchosis in a flock of sheep kept at a research farm in Kentucky, US.
The development of resistance by nematodes to broad-spectrum anthelmintics is of particular concern. Currently, three different chemical groups — benzimidazole, levamisole and avermectin — are commonly used for deworming. A varying degree of resistance in nematode populations against these anthelmintics has been widely reported throughout the world. The development of AR, therefore, has resulted in lowered animal productivity due to heavy nematode burden.
Owing to the development of resistance, it has been commonly observed that despite repeated deworming of the animals with anthelmintics, animals keep passing a small number of helminth eggs or, after a short breather, again start passing eggs.
In such situations, the farmers or veterinarians remain relatively carefree, having a false sense of security.
If anthelmintic resistance is known to have developed, a professional would remain on the lookout for trouble. He or she would also think of alternate control strategies as described above. It was, therefore, imperative to study the development of anthelmintic resistance in nematode populations of sheep and goats in Pakistan. This could help in identifying the problem of deworming failures, loss of efficacy of some anthelmintics and selecting a dewormer of choice based on high efficacy.
Keeping in view the importance of anthelmintic resistance, the Higher Education Commission (HEC) recently funded a project in which the department of veterinary parasitology, University of Agriculture, Faisalabad, was told to screen out GIT nematode populations of sheep and goats, kept at farms in the Punjab and NWFP, for the presence of anthelmintic resistance. During the first year of the project, a group of parasitologists of the aforementioned department visited government livestock farms in the Punjab (Sarai Muhajar and Kallurkot in Bhakar District) besides private farms near Faisalabad.
The study encompassed two aspects. Firstly, the parasite control practices used by the private farmers and government livestock assistants were observed and secondly the prevalence of anthelmintic resistance was studied. The farmers were interviewed in detail, during visits to their farms and fields. The issues discussed included local treatment practices and their effectiveness against the problem. They were also asked about the use of modern anthelmintics like benzimidazole, levamisole and avermectin.
It was found that the farmers identified the drugs through their colours and that they had practically no knowledge about dosages and administration techniques. Some farmers were aware of the parasites and their symptoms but used things like Kamela, Ajwain, Tobacco and other herbs for the treatment of these parasites.
Under the project, a detailed history about worm control practices was collected from government livestock farm assistants, through a prescribed questionnaire, and this helped the researchers assess the underlying factors in the development of AR.
To determine the prevalence of anthelmintic resistance, faecal samples from different flocks (private and government) were collected and examined for the parasitic infection in the chemotherapy laboratory, University of Agriculture, Faisalabad. The collected samples were subjected to various analyses to determine the worm burden in sheep and goat.
The animals meeting the criteria for experiments were selected and given different anthelmintics. After a fortnight, faecal samples were collected and analysed for the prevalence of AR. It was observed that AR in sheep and goat nematodes had been developed against two groups of anthelmintics — benzimidazole and levamisole.
After the detailed exercise, it was concluded that private farmers had to face drug resistance due to underdosing, improper administration, adulteration and dilution of drugs. However, at the government-run livestock farms, resistance was due to the lavish use of the same type of drugs for a long period of time. Unavailability of worm-free pastures for grazing was also a major factor.
Based on the one-year study, it can be recommended that a broadbased public education and awareness programme should be launched which would deal with the importance of prevention and control of the parasitic diseases.
Under this initiative the farmers and government functionaries should be educated about the need to:
— Lessen the animals’ exposure to a particular group of anthelmintics;
— Ensure adequate rotation of dewormers;
— Apply correct doses of the medicine;
— Examine properly every animal before introducing it to the flock;
— Ensure adequate pasture management practices, and;
— Improve the nutrition of animals.
Apart from the above, regular monitoring of the development of resistance should be undertaken.
The writers teach at the department of veterinary parasitology, University of Agriculture, Faisalabad
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