This article written by Dr. Reynold Bergen, BCRC Science Director, originally appeared in the September 2017 issue of Canadian Cattlemen magazine and is reprinted on the BCRC Blog with permission of the publisher.

Weed seeds and invasive species may be present even in well-managed pastures and rangelands, but it is hard for them to germinate, establish and spread in healthy, competitive forage stands. Stresses like severe drought, overgrazing, heavy traffic or excavation can weaken forage stands and create opportunities for unwanted plants to take root.

Researchers are now studying whether similar principles may apply to animal health and disease processes. For example, calves that were perfectly healthy on the farm can face a serious risk of bovine respiratory disease (BRD) in the feedlot after experiencing the stresses of weaning, commingling, transportation and ration changes. Dr. Trevor Alexander of Agriculture and Agri-Food Canada’s Lethbridge Research Station and collaborators from the University of Calgary are studying bacterial populations (the microbiota) in the respiratory tract of feedlot cattle. They published the results of a small study supported by the Beef Research Cluster earlier this year (The nasopharyngeal microbiota of beef cattle before and after transport to a feedlot; BMC Microbiology 17:70).

What they did: Little is known about what the “normal” respiratory microbiota looks like in cattle, let alone how it changes in response to any given stress. Because exposing calves to multiple stresses at the same time may have produced large, complex, difficult to interpret changes in the microbiota, this team focused on the effects of simply moving cattle from the home farm into the feedlot. They used 14 Angus x Hereford heifer calves (640 lbs) from Continue reading →