On northern latitude winter rangelands, the effects of low forage nutritive value on animal performance are usually mitigated by supplementing livestock, although the amount of supplement is often not adjusted for available forage quantity and nutritive value. The objective of this study was to assess the potential of live (fall, spring) and dead component of two cool-sea-son bunchgrasses to meet nutritional requirements of cattle from fall through spring on a foothills range site in southwestern Montana. Several nutritive characteristics of live and dead components of bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] A. Love) and Idaho fescue (Festuca idahoensis Elmer) were assessed during the winters of 1991–1992 and 1992–1993. In addition, rate and extent of dry matter disappearance, and extent of crude protein disappearance were determined in-situ using ruminally cannulated beef cows. Nutritive value of forage components of bluebunch wheatgrass and Idaho fescue were similar fall through spring. Fall growth was similar in CP and digestibility to April growth, and maintained these levels through winter. With normal forage intake rates on winter range, CP levels of standing dead material would not meet animal protein requirements fall through spring. When fall growth is not abundant, more protein supplement would be needed than when it is abundant. Matching animal requirements to forage availability and nutritive value, supplementing only when necessary and in appropriate amounts, could help reduce costs of winter feeding. Key words: Winter grazing, bluebunch wheatgrass, Idaho fescue, forage quality, cattle
Cubed Alfalfa Hay or Cottonseed Meal-Barley as Supplements for Beef Cows Grazing Fall-Winter Range
