Page 98 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

Epidemiology of Animal Poisonings in Asia Chapter | 4 65

VetBooks.ir because of the ubiquitous presence of dioxins in the envi- impact of garbage on man and environment is talked
about quite often, but it’s far more lethal brunt on ani-
ronment, the threat of dioxin contamination posed by feed
ingredients may originate from many different sources.
mals almost always misses the headlines. A cow eats a
Mycotoxins can concentrate in dried distillers’ grains with plastic bag from the River Ganges in India; hundreds of
solubles (DDGS) during the processing of grains for etha- cows die annually from choking on plastic bags contain-
nol production. They also concentrate in cereal bran. ing vegetable waste. For those living on the coasts, a
Cadmium is a ubiquitous contaminant that is present in mere walk on the beach can give anyone insight into
many feed and feed ingredients, in particular minerals and how staggering our addiction to plastic has become as
forages grown near smelting and mining areas. As and Hg bottles, cans, bags, lids and straws (just to name a few)
are heavy metals that are widespread in the environment are ever-present. For other areas that insight is more
and can be found in many feeds, in particular in feeds of poignant, as the remains of animal carcasses can
marine origin. Pb is also a ubiquitous contaminant frequently be observed; the plastic debris that many of
(Swarup et al., 2005). Veterinary drug residues may be them ingested or became entangled in still visible long
found in food products as a result of the carryover of vet- after their death. Sadly, an overwhelming amount of
erinary drugs in feed during feed production. The contin- plastic pollution isn’t even visible to the human eye,
ued presence of organochlorine pesticides in the with much of the pollution occurring out at sea or on a
environment, as well as their ongoing use in some coun- microscopic level (Gregory, 2008).
tries, can cause exposure through food as a result of accu- Several countries of Asia have an open garbage
mulation in the fat tissues of animals that have been fed system, which means open garbage bins on the roads
on contaminated feed (Gupta, 1986). Contaminated feed overflowing with stinking waste. Dogs, monkeys, pigs,
containing salmonella has a direct impact on transmission rats and cows eat whatever they can find to survive. The
to humans via food of animal origin. Some endoparasites numbers of stray dogs, rats, and monkeys are equal
of animals, such as Echinococcus, Toxoplasma gondii, to the amount of garbage on which they feed and multi-
Cysticercus, and Trichinella, present a risk to human ply. In cities and towns, large numbers of cows on
health, and ingestive stages can contaminate animal feeds. the roads eat from garbage bins, foraging for fruit,
There are many toxic plants found in grasslands around vegetable leftovers, anything edible and anything
Asia. Their toxic effects, and the potential presence smelling like food. Since plastic bags have invaded our
of some toxic compounds in milk and meat, are well lives, almost all garbage and food waste is disposed in
documented. However, there is a lack of information plastic bags. These bags spill out either on the road or
about metabolic rates, residues, maximum residue limits from municipality dustbins. Since the plastic bags are
(MRL), and average daily intakes (ADI) for these differ- knotted at the mouth, cows, unable to undo the knot, eat
ent toxicants (NRC, 2005). One report from Bangladesh food leftovers including the plastic. Slowly, over time,
indicates that the pleuromutilin antibiotic tiamulin is they build up a huge amount of plastic inside their sto-
known to produce a negative interaction in broilers when machs. It gets entangled with different materials and it
administered in combination with several ionophore antic- becomes hard like cement inside their rumens, which is
occidials, such as salinomycin (Islam et al., 2008). This the first belly of the cow apart from the plastic
risk pathway of feed associate contaminants can be con- completely choking the digestive system of the cow and
trolled by following Good Agricultural Practices (OIE, causingexcruciatingpainto the animal. Consequently,
2007; FAO/WHO, 2007). plastic residues enter the human food chain through
dairy and animal products.
Animals, especially cattle, ingest the plastic and
PLASTIC BAGS
develop complications, which finally result in their death.
The presence of plastic bags in the Bay of Biscay (in Usually there are no reports except if cattle deaths have
western Europe) over 120 miles from shore in waters over medico-legal implications to settle compensation claims.
4000 m in depth have been observed. A whale dies in an Otherwise, there are no figures of the number of animals
urban harbor and, on being autopsied, reveals a stomach dying from plastic and toxic waste. A lot of cases go
full of plastics. Whale species in particular are highly sus- unreported. The rumen is one of the four compartments of
ceptible to swallowing plastic bags, as they are believed the cattle’s digestive system. The feed enters from the
to strongly resemble their target prey, squid. Other species reticulum to the rumen, omasum and finally the aboma-
of large whales, which take large mouthfuls of water dur- sum (true stomach). But when the plastic in the reticulum
ing feeding, also take in plastic bags by accident and blocks the feed from entering the rumen, suffocation
hence are also at risk (Anon, 2014). In developing coun- occurs and the animal dies (Anon, 2013b). Rumenotomy,
tries such as Pakistan, Nepal, India and several other the surgical removal of plastic up to 70 kg from the cow,
countries in Asia and other countries of the world, severe has been reported (Anon, 2014).