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Farming and Livestock

Special Report : The danger to humans of chemical and drug residues in livestock

8 November 2022
Reading time: 6 minutes

The use by livestock breeders of chemicals, as well as high doses of other drugs, can be extremely harmful for human consumption and could cause serious illness.

Some of the chemicals are fed to or injected into animals to stimulate growth and prevent disease and some are ingested accidentally.

Many scientists, as well as environmental and consumer groups, contend that residues of these chemicals accumulate in humans and can eventually cause serious illnesses.

This was one of the reasons a veterinary doctor in Maiduguri has called on the government to regulate the use of these drugs.

Ali Umar Gajibo, a veterinary doctor from the Borno State chapter of the National Veterinary Research Institute (NVRI), told RNI that veterinary drugs or chemicals were administered to animals for therapeutic, prophylactic and diagnostic purposes or to modify the animals’ physiological function or behaviour.

“They are used throughout the world and, unfortunately, more than half of all medicines are prescribed, dispensed or sold improperly. In fact, some livestock rearers often misuse the drugs on purpose so that they can make more profit when selling the animals. Many do not know the effects it can have on human health.”

Gajibo said the drugs had the potential to generate residues in the animal-derived products that could pose a health hazard to consumers.

He said the most likely cause of drug or chemical residues might be due to improper use of the drugs and the failure to keep the animal in the withdrawal period before sending it to be slaughtered.

“Normally, the residual amount ingested is in small amounts and not necessarily toxic. That is why we advise livestock breeders to use drugs or injections properly, based on prescription and medical tips from veterinary doctors.

“However,” he said, “the government needs to come up with strategic measures to address the  improper use of veterinary drugs and injections by local farmers or livestock breeders by establishing a functioning regulatory framework that will guide the use of any kind of veterinary medicines. It also needs to give more power to veterinary doctors, so that they are able to monitor and observe the condition and health of animals before they’re sent to be slaughtered. All veterinarians should be given this power, not only in public abattoirs but also on individuals’ farms.”

Bukar Mohammed, a livestock breeder told RNI that he had been rearing livestock, mostly cattle and sheep, for many years.

“We buy our livestock from neighbouring countries, such as Cameroon, Chad and the Niger Republic, among others. We also buy from places closer by, such as Monguno, Benisheikh and Gubio in Borno State. The animals we buy are mostly cheap because many of them are suffering from famine and malnutrition. We give such livestock proper treatment and nutrient feeds until they are healthy again. Once they fully grown we sell them in the market for a good profit.

“This is the normal practice of how we rear our livestock up until we sell them. We have been doing this for many years. But there are some breeders who often use veterinary drugs and chemicals to boost the growth of their animals within a short period of time and, by doing so, they make huge profits. Most of us believe this is inappropriate. That’s why I grow my livestock naturally without using such chemicals or drugs. I know the implications too many chemicals or drugs can have on human’s lives.”

Modu Kolo Alhaji Modu said he mostly bred cattle.

“We rear our livestock in two ways. First, during the rainy season, we will release all the animals into the forests for grazing daily from 8am to 5pm. This continues for at least two months until the rainy season ends. Second, after the rainy season, we keep the animals at home and provide them with all kinds of feeds that will help them grow faster.

“Sometimes we use veterinary drugs and chemicals on animals that are very hungry, so that they will start eating properly and also so that they look impressive and capture the minds of prospective buyers.

“The veterinary drugs are important because they help animals to grow faster and build up their bodies. Their coats are smooth and shiny and this pleases all prospective buyers. We make a lot of profit when sell such animals. That’s why we often use drugs on our livestock. Usually we do so once every two weeks,” Modu said.

The Department of Primary Industries and Regional Development in Western Australia, an area in the world that is well known for its high standard of breeding, said a residue was what remained of a chemical or heavy metal (for example, lead, arsenic, cadmium) inside an animal. All chemicals and heavy metals caused residues but the time taken for a residue to break down varied depending on the substance and the animal.

Residues might be harmful if they exceeded the maximum residue limit (MRL) for the chemical or heavy metal. The MRL was the maximum amount of residue allowed in a food to be safe for human consumption.

It said not all residues were harmful and products containing residues less than the MRL were considered safe for human consumption.

Harmful residues might occur when: a veterinary chemical label instruction or the veterinary directions were not followed; the withholding period (WHP) or export slaughter interval (ESI) of a veterinary chemical was not observed; livestock were exposed to plant chemicals used to control weeds or insects; unregistered chemicals were used on livestock – these chemicals did not have WHPs and were of an unknown residue risk; livestock accessed hazardous materials, such as lead batteries found in places like the farm dump, sheds, old yards, old house sites and painted materials; livestock grazed on land contaminated with persistent chemicals, such as organochlorines, for example old potato paddocks, stock feed treated with a pesticide was given to livestock, such as pickled grain.

The department said it was difficult to tell if an animal contained harmful residues because not all chemical or heavy metal residues caused signs of illness in animals.

It was important to note that the MRL established safe limits for humans, not animals. Exceeding the MRL would not necessarily affect the health or welfare of an animal, only the meat consumers.

SHETTIMA LAWAN MONGUNO

About the author

Elvis Mugisha