Symposium on Pasture Methods for Maximum Production in Beef Cattle: Protein and Energy Requirements for Female Beef Cattle

In early studies the nutritive requirements of beef cows was determined in the dry lot by group feeding different rations during the winter and allowing the experimental animals to graze together on pasture during the summer, using weight changes of cows and weaning weights of calves as the main measures. Several reports of experiments of this type are available where various feeds were compared for wintering cows (Arnett, Baker and Vinke, 1926; Arnett and McChord, 1927; Vinke, 1927; Vinke and Dickson, 1933; Hubbert and Sawyer, 1951). These trials were based on utilizing local feeds, such as silages, corn fodder and hay. No attention was given to protein and energy as such. These workers were concerned with developing economical rations for their areas. The same procedures as above have been used to conduct experiments comparing supplements on winter range (Lantow, 1930; Black, Quesenberry and Baker, 1938; Stanley, 1938; Foster, Biswell and Hostetler, 1945; Hargrove, 1947; Johnson, Moxon and Smith, 1952; Nelson et al., 1954a; James, 1957; Zimmerman et al., 1957; Duvall and Hansard, 1967). Under range conditions, forage intake has not been measured accurately.