Impacts of Gas and Oil Production on Livestock
December 30, 2013
Are cattle living near oil and gas wells at risk? Raising livestock adjacent to oil and gas production facilities has become a way of life for ranchers in certain regions of Canada and the U.S. The animals are often exposed to emissions released into the air – such as sulfur dioxide, hydrogen sulfide and volatile organic compounds (including benzene and toluene). Some animals are exposed to liquid products such as crude oil, drilling mud, frac fluid, water with high salt content and a variety of other materials used in gas and oil production.
After concerns from the livestock industry were voiced during the 1980s and 1990s several symposiums and research studies looked at the possible toxicological affects on cattle from prolonged low-level exposure to these contaminants. Special attention was paid to any possible affects on reproduction and immunity. Several studies examined the effects of these emissions to determine whether animal health was affected, and whether there were effects on the respiratory, immunological and reproductive systems. Cheryl Waldner, DVM, PhD, Professor of Epidemiology, Large Animal Clinical Sciences, Western College of Veterinary Medicine (University of Saskatchewan) conducted an intensive on-farm study of herds in western Alberta for two years.
"There were many measures of herd performance that we looked at and didn't find differences in the herds that were more exposed, which is good news, but there were some points of concern and questions that did come out of that study. One of them was related to death loss in young calves. There were also some additional findings related to potential impacts on the immune system. The affects on the immune system were suggested by differences in counts of specific cell types when we looked at lung pathology or pneumonia in baby calves, and treatment rates in baby calves," says Waldner.
"The immune system findings were associated with exposure to volatile organic compounds such as benzene and toluene. You can't single out the individual compound that was most toxic because we were looking at mixtures, but we were measuring benzene and toluene as representative of the volatile mix that comes off some of these facilities," she explains.
"The increase in calf mortality was most strongly related to exposure to sulfur dioxide (SO2). This was probably the most substantial finding from the study, but the immune system findings showed a consistent pattern across cell types in the blood of different age groups." The calves that were more exposed had a higher occurrence of lung problems (that showed up in necropsy examinations) than those that were less exposed," she says.
"There were a few other puzzle pieces that showed a pattern related to the volatile organic compounds (VOC) that warranted some attention, for example a small change in time to pregnancy. But when we looked at abortions, stillbirths, pregnancy rate, there were no appreciable differences across the study. The exposure-associated differences were observed in the very young calves," explains Waldner.
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This study was designed to look at differences between herds raised in areas exposed to typical operating conditions in the oil/gas industry at that time and what would be seen with livestock that were not exposed to these conditions. "It wasn't designed specifically to look at accidental releases of gas, but rather the long-term affects of typical production. We addressed the question of whether there were differences between the ranches where cattle were closer and potentially more exposed to these emissions, compared to cattle that are farther away. We looked at what was happening with gas and oil production in 2001 and 2002," she says.
"I understand things have changed since that time, with some new processes and operational practices though some facilities appear to be very much like they were then. A lot of the environmental concern has shifted away from flaring – which was a big issue at that point in time – to issues like fracking.
"Flaring at oil and gas sites was a lot more common 10 to 20 years ago. Flaring is the burning of unwanted waste gas. If an oil well had some gas coming up with the oil and the gas was not economically feasible to process, they used to flare it. But now, at most sites, they've figured out alternate ways to manage the gas and don't have to flare on a regular basis," Waldner explains.
Fracking is now of more concern in environmental debates (due to potential water contamination) rather than air pollution, in many areas. Fracking involves putting water down the well to help bring up the oil. "This is where questions are focused right now, when you talk to people who live near these facilities. Some are worried about whether their water sources might be contaminated. There has been some research on this, but not very much, so there are still a lot of questions," she says.
She advises producers to consult with their herd health veterinarian if they suspect a problem; the veterinarian could help document the exposure and current health of the herd. Detailed records of herd management (historical and current production) can be useful, looking at a sufficient period before the cattle were exposed, along with any substantial changes in production, feed consumption, illness or treatments.
The health program must be evaluated in terms of adequate nutrition, parasite control, vaccination, breeding soundness of bulls, etc. to make sure there are no other causes for decreased performance. Other conditions such as diseases like BVD, nutritional deficiencies, etc. would have to be ruled out when looking at any drop in reproductive performance or overall herd health. "It may be difficult to determine conclusively whether oil and gas activity is responsible for a specific problem. It helps if the producer can demonstrate that herd management is not the primary factor responsible for observed changes," says Waldner.