OAHN Small Ruminant Project: Sheep Flock Trace Mineral Surveillance (in progress)

Project Lead:Dr. Emma Borkowski

Collaborators: 

Project Proposal

Historically, copper toxicosis has been commonly reported in Ontario sheep flocks.  Sheep are less tolerant of excess copper in the diet than other livestock, which has contributed to caution among veterinarians, producers, and nutritionists regarding copper supplementation in a mineral program.

Field veterinarians participating in the OAHN Small Ruminant Network have reported increasing suspicion of copper deficiency in lambs. In recent years, changes in soil and forage mineral composition may have occurred, and management strategies intended to prevent copper toxicosis, such as the use of mineral supplements with high molybdenum and very low copper concentrations, may be inadvertently contributing to undiagnosed copper deficiency in Ontario sheep populations.

Sheep mineral status is influenced by multiple factors, including soil mineral concentrations, forage composition, climate and supplementation practices. These parameters vary geographical across Ontario, resulting in regional differences in mineral availability and status. Monitoring trace mineral status at the flock level is considered best management practice to support optimal animal health and productivity; however, this practice is not routinely implemented by many Ontario sheep producers and veterinarians, often due to expense.

Analysis of copper concentrations in sheep liver samples submitted to the Animal Health Lab between 2020-2025 provides additional context. Among sheep less that one year, 30% of samples had low hepatic copper concentrations, while 20% were elevated. In sheep older than one year, 13% of samples were classified as low and 13% as high. It is important to note that this data was derived from a biased population, typically animals that were clinically ill or under investigation for suspected trace mineral imbalances and therefore do not necessarily reflect the mineral status of the general, healthy breeding ewe population in Ontario.