Mineral assessment of open range livestock production on The Warm Springs Indian Reservation

Graduation date: 2010The Warm Springs Reservation is located in central Oregon. Livestock production\ud consists of beef (commercial with an Angus, Horned Hereford base) and roping\ud (Corriente and Longhorn) cattle and horses that forage most of the year on the open\ud range within reservation boundaries. Forage consists of annual and perennial grasses\ud and shrubs, with winter feed supplementation on some cattle operations. Calving\ud season tends to be year round, with the concentration of managed calving during the\ud early spring. Calf crops vary from 40% to 95%. Conversations with tribal producers\ud indicate a past history of retained placentas and reproductive issues, indicating that\ud mineral deficiencies may be present. Previous blood samples on horses and cattle\ud have documented low levels of selenium. An analysis of blood serum mineral levels\ud in breeding cows was conducted, along with the oral history from two tribal producers,\ud in order to assess mineral differences and potential calf crop differences in cattle.\ud Three herds of ten breeding cows each were tested in the fall of 2007. The tested\ud herds were: I) crossbred Angus with mineral supplementation (AxS), II) crossbred\ud Angus without mineral supplementation (AxU), and III), and crossbred Longhorn\ud without mineral supplementation (LxU). Plant samples were also collected in\ud October 2008 and May 2009 to determine mineral content of forages within the study\ud site area. Results demonstrated that there was a significant difference in serum\ud selenium content between AxS and AxU, and a difference in calf crops. There was no\ud significant difference in serum selenium content of AxU and LxU, although there was\ud a difference in calf crops. Plant mineral levels varied by species and season, but were\ud consistently inadequate in sodium, zinc, selenium, fall phosphorus, and iodine. A\ud blood analysis of range cattle, followed with the appropriate mineral supplement can\ud address local deficiencies and potentially contribute to overall health and productivity\ud of range livestock at Warm Springs