In Drilling Down, we wrote about Elizabeth Chandler, a veterinarian in western Colorado. Dr. Chandler has been observing health changes in livestock, including goats, pigs and cattle, that are kept near natural gas production activities. She is particularly concerned about reproductive changes, including unexplained, dramatic increases in birth defects, stillbirths, and reduced fertility, where she has ruled out other potential medical causes through testing. One hog farmer estimates his losses at more than $50,000. We also wrote about Rick Roles, who observed reproductive changes in his horses and goats, and ranchers in New Mexico who have lost cattle that were exposed to oil and gas waste.
Other parts of the country are now reporting livestock impacts from oil and gas production. Oil and gas chemicals are suspected as the cause of the deaths last week of 16 cattle in Louisiana. A Pennsylvania farmer is concerned about the recent deaths of four cattle. A farmer in Arkansas told me about her concerns that natural gas production is the cause of death and other health effects in her cows. Almost 25% of her cattle died when kept in a pasture where three wells were drilled above the water source - a loss of over $35,000. She has also observed stillbirths, birth defects, and drastic reductions in milk production. Tests indicated lead, arsenic, barium and other heavy metals that are above safe levels in their soil and water. A goat farmer in Oklahoma who is located across the road from oil and gas activities told me that her goats stopped producing milk; she sold them all and her farm is now in foreclosure.
A 2000 study looked at possible associations between oil and gas operations and cattle reproduction and mortality, and found an increased risk of stillbirths linked to exposure to flaring of sour gas (gas with high levels of hydrogen sulfide). A 1991 study reviewed seven cases of suspected poisoning of livestock related to oil and gas materials in Oklahoma, cases described as routine in oil and gas producing areas of the state. We should be concerned about all of these reports; we need more science on this topic. Livestock incidents may be an indicator of contamination of air and water that can impact humans as well as animals. In addition, there may be risk to humans who eat or drink products from these animals.
 Waldner, C. L. et al., Associations between oil- and gas-well sites, processing facilities, flaring, and beef cattle reproduction and calf mortality in western Canada," Preventive Veterinary Medicine 50 (2001) 1-17.
 Edwards, W.C. and D.G. Gregory, "Livestock Poisoning from Oil Field Drilling Fluids, Muds and Additives," Veterinary and Human Toxicology 33 (5) October 1991, 502-504.