Epidemiological intelligence for grazing management in strategic control of parasitic gastroenteritis in small ruminants in India – A review

Because of the environmental and consumer concerns arising out of exponential growth in human population the world over, a term Sustainable Development has become an integral international concept, which is defined as one which meets the needs of the present without compromising the ability of future generations to meet their own needs. Ruminant animals appear sustainable as they do not compete with man for food, play a crucial role in the conversion of low quality plant material and crop residues to high quality human food as well as return valuable plant nutrients to the soil. Parasite control in ruminant livestock is a first-order input in any sustainable animal production system. As sustainable development is a compromise between reducing environmental degradation and positive economic growth, sustainable parasite control should aim towards less intensive, lower input, lesser risk of parasite induced losses with greater opportunities for integration of all available control resources. The compound scenario of rising anthelmintic resistance, food and environmental security and apathy of the pharmaceutical industry to go for the invention of new anthelmintic compounds has triggered the need for optimising the use of available anthelmintics with integration of all other alternative means for sustainable worm control. The “Sustainable Control of Parasitic Gastroenteritis in Ruminants” is thus encompasses a multidisciplinary approach involving integration of chemotherapy, grazing management, biological control, worm vaccines, genetic resistance of hosts, mathematical model based decision support and other strategies, if any. There is no single requirement more crucial to the rational and sustainable control of helminth parasites in grazing animals than a comprehensive knowledge of the epidemiology of the parasite as it interacts with the host in a specific climatic, management and production environment. In its absence, anthelmintic treatment is either given suppressively which provokes resistance or therapeutically which risks clinical disease and production losses. Sustainable parasite-control programmes require knowledge of seasonal larval availability, origin of larvae contributing to any peaks and climatic requirements for worm egg hatching, larval development and survival. Control measures based on this knowledge include strategic anthelmintic treatments and various forms of grazing management. While these measures can reduce the frequency of anthelmintic treatment required, their effect on selection for drench resistance is more problematical, unless they can be combined with other forms of control to reduce our current dependence on anthelmintics. The present article deals with sustainable nematode parasite control in small ruminants in India through grazing management using epidemiological intelligence.