TIPS FOR INTEGRATED CONTROL & MANAGEMENT OF ECTOPARASITES OF LIVESTOCK
Dr.Ashutosh Mishra,TVO,Jahanabad
Introduction:
Livestock is an integral part of the agricultural production system in India, play an important role in national economy as well as in socio-economic development of rural households. The livestock and fishery sector accounts for 31.7% of agricultural GDP and about 5.21% of total GDP in 2019-2020. The share of livestock in the gross value of agricultural and allied output has reached 28.4 % in 2010-2011 (CSO, 2011).
Parasitic arthropods continue to be a major factor influencing human and animal health in many parts of the world including India. They can act directly on their animal hosts,
causing annoyance, irritation, phobia leads to reduced weight gain and milk production,
anaemia due to loss of blood, paralysis, behavioural modification, immune suppression and damage to hides (Rehbein et al., 2003). They can also act indirectly as vectors/intermediate
hosts of various viral, rickettsial, bacterial, protozoan and helminth parasitic diseases and the
site of their bite may provide a route for superinfection. The economic and social significance of these pests are great (Haufe & Weintraub. 1985; Yuill, 1991; Uilenberg, 1992). This is
particularly true when European breeds are introduced into tropical or subtropical areas with the aim of increasing meat and/or milk production (Uilenberg. 1982). The control of parasitic arthropods aims at increasing stock production and opening environments for more effective
human exploitation.
In order to limit the direct and indirect effects of arthropod parasite the reduction of the parasite’s population is necessary. For instance, to reduce the incidence of vector borne disease either vector borne pathogens should be controlled or vector itself. Moreover, controlling the vector is better than to controlling the pathogen transmitted by it because latter may be many or effective methods may not be available (Provost & Uilenberg. 1990). There are various methods available in practice or under laboratory development for controlling the parasitic arthropods menace of livestock like chemical pesticides, herbal formulations, vaccinations, genetically modified arthropods, mechanical destructions of parasite habitat, selection of resistant breeds and other biological methods.
Although, integrated pest management (IPM) programme was introduced in 1960, till date, chemical control methods are principal measure for controlling the parasitic arthropods.
The approach based on synthetic chemicals application suffers from drawbacks such as repeated applications, environmental pollution, chemical residues in livestock products and selection of resistant pests. However, the IPM can decrease frequency and intensity of genetic
selection by minimal reliance on chemical pesticides and integrating the other friendly methods of ectoparasites control.
The term integrated management of ectoparasites of livestocks implies a rational use of a combination of biological, biotechnological and chemical control measures with farming practices or breeding strategies in order to reduce the use of chemical control agents to an absolute minimum. A classical example of this approach is the combination of anti-tick vaccine and acaricides in order to control the tick manifestation (Rhipicephalus microplus) and finally tick borne disease in Australia, Latin American countries (de la Fuente et al., 2007). The various control methods for ectoparasites of livestock are discussed here which may be used alone or combination with the others.
- Chemical control methods
It will probably always be a component of IPM systems. The judicious use of pesticideswhether traditional classes of compounds (e.g. organophosphates, carbamates, formamidines and synthetic pyrethroids) or newer groups of compounds (e.g. insect growth regulators or avermectin-like products) – forms an integral part of almost every IPM system. The future molecules may be natural products and their synthetic analogues, as well as by synthetic neurohormone mimics, chemical repellents or attractants. Moreover, attention should also be paid to improved formulations and methods of application. - Modification of environments
The ectoparasites can be controlled by manipulating their breeding places such as pastures,
sheds and kennels. The pasture rotation is to remove stock for a period when parasites/their
stages experienced heavy mortality and develop a spelling schedule. The pasture can also be
managed to unsuitable by periodical ploughing, burning weeds and cultivating legume of
genus Stylosanthus which immobilizes and kills certain species of ticks. With homing instinct
of ticks in India the periodical spray of sheds by long acting hydrocarbons, removal of cracks
and crevices and even washing of sheds with water pressure can minimize the population of
ectoparasites. - Raising of resistant host
Different breed of cattle vary in their susceptibility to ectoparasitic infestation. In 1900,
Munro Hull, a dairy farmer noticed that certain animals are less affected by ectoparasites.
Later it was found that Bos indicus cattle are more resistant to many tick and fly borne
diseases, as well as to attack by ticks, than the B. taurus breeds. This resistance is related to
natural selection, since the B. indicus breeds have lived in the same area with the ticks for
aeons (Henrioud, 2011). Tick resistant breeds of cattle have now been developed in an effort
to find animals that are productive (particularly for milk) under tick challenge and in a
tropical environment. The development of these breed started with the parallel development
of cows with acceptable levels of milk production and bulls with high tick resistance and
from there excellent dairy breeds, such as the Australian Friesian Sahiwal, have been created.
Resistance for ticks is a heritable character and several workers have estimated the
heritability for resistance to Rhipicephalus (Boophilus) microplus (Machinnon et al. 1990).
Cattle have been selected for tick resistance and significant progress has been made with the
development of breeds of tick resistance and at the same time, show good productivity. It has
been shown that the heritability of tick resistance ranged between 40 and 50 %. - Genetic modification in pest
The prime example of genetic control is the sterile insect technique, perhaps the most
revolutionary advance in arthropod pest management of the twentieth century. This technique
is based on the mass production of an arthropod pest to be controlled or eradicated, the
inducement of sterility in adults through irradiation, and subsequent flooding of a target area
with sterile males. The idea of the release of sterile males of the same species into natural
populations was propounded by E. F. Knippling in late thirties. Later utilized with
commendable success by Lindquist et al. (1993) for the eradication of screw worm fly,
Callitroga hominivorax. The technique is likely to be effective in case where 1. Natural
population of target species is low, 2. Female mates only once in its life, 3. Easy to reare in
large numbers and 4. There is no migration of species outside in the area of operation. Hence,
detailed knowledge of ecology and population dynamics is imperative to decide the time and
place of release. The ectoparasites can be sterilized either by chemosterilants or genetic
manipulations employing chromosomal translocation, cytoplasmic incompatibility and hybridization. Other genetically-based control components for the future could include the introduction of deleterious genes, induced mutations or hybrid sterility.
- Biological Methods
Biological control is always an attractive option to include in IPM systems. In veterinary
entomology, the utility of this component is probably limited to manure- breeding flies.
Hymenopterous parasites have frequently been incorporated into IPM systems to control
house flies and stable flies, while predatory beetles and competitors (e.g. dung beetles) have
been utilized in the management of horn flies (Haematobia irritans). The parasites like
Hunterellus hookeri, Ixodiphagus spp and pathogens like Bacillus thurengiensis, B.
sphericus, fungi of genus Beaveria are known to kill certain species of ectoparasites.
Predators like birds (Oxpeaker) predates on ticks and the spider Phidippus rimator on soft
tick in North Callifornia. Demerits of these bio-agents like poor control of ectoparasites, the
problem of dispersion from the point of release, their multiplication hindrance of insecticidal
sprays and difficulty in monitoring their effect, restrict their wide use. In the future, with the
practices of genetic modification and manipulation coming into general use, genetically
engineered microorganisms may prove to be the strongest biocontrol component within some
IPM systems. - Mechanical control
Mechanical control can provide a simple and unique technique in ectoparasite control program. For example, effective manure management and disposal can reduce fly populations by as much as 50% in cattle feedlots. Similar results have also been reported from poultry egg-layer operations. Trapping also has a potential role in reducing fly populations in the vicinity of confined livestock and poultry. Trapping is also increasingly used with success in the control of tse-tse flies in Africa. This technology relies on dependable attractants, functional trap design, proper trap placement and regular servicing. In the case of integrated tick management systems, mechanical control components have included vegetation management as well as wildlife host management. - Immunological methods
Immunological control of ectoparasites of livestock and poultry has been an effective component of integrated control in the past and will, undoubtedly, assume an even greater role in the future (George, 1992). Fundamental information on the immunological responses of livestock and poultry to natural and synthetic antigens has provided hope for the development of vaccines. Vaccines for use in controlling ticks, biting flies and even internal livestock parasites are on the verge of commercialization.
In the early 1990s, vaccines inducing immunological protection on vertebrate hosts
against tick infestations were developed and commercialized. The commercial vaccines,
Gavac and TickGARD, contained the recombinant R. (B.) microplus Bm86 gut antigen.
These vaccines reduce the number of engorging female ticks, their weight, and reproductive
capacity (Willadsen et al., 1989; de la Fuente and Kocan 2003). Vaccine-controlled field
trials in combination with acaricide treatments demonstrated that an integrated approach
resulted in control of tick infestations while reducing the use of acaricides (de la Fuente et al.,
2007). In addition, these vaccines may also prevent or reduce transmission of pathogens by
reducing tick populations and/or affecting tick vector capacity (Rodriguez Valle et al., 2004;
de la Fuente et al., 2007). In India, homologue of Bm86, Haa86 has been cloned and
expressed in both prokaryotic and eukaryotic systems. The expressed protein has been
characterized and tested against both homologous (Hyalomma anatolicum) and heterologous
(Rhipicephalus microplus) challenge infestation (Azhahianambi et al., 2009; Kumar et al.,
2012a). The efficacy of rHaa86 was compared with rBm86 based vaccine in both
homologous and heterologous challenge infestation and the result shows that species-specific
vaccine having batter effect on tick control (Kumar et al., 2012b). Last but not the least, the
control of ectoparasites is fundamentally an economic problem and must be dealt on the basis
of cost-benefit ratio.
Conclusion
At present, the implementation of integrated control of ectoparasites of veterinary
importance is limited. However, serious drawbacks of chemical pesticides attracting towards
the adoption of integrated pest management program. Integrated pest control requires many
technologies for incorporation into specific pest management systems. Individual components
include new chemicals, formulations and delivery systems, biological control, mechanical
control, immunological control, genetic control, and regulatory control. Researcher should be
encourage to develop the cost-effective and environmentally-compatible IPM systems for
future progress.
Reference-On Request
