Influence of Winter Nutrition on Beef Cow Reproduction

Intake and digestibility of low-quality native grass hay by beef cows supplemented with graded levels of soybean hulls2

“…Grass hay utilized in Oklahoma for beef cattle nutritional studies is composed largely of bluestem (little and big), with smaller amounts of switchgrass and indiangrass (Nelson et al, 1952;Pinney et al, 1972;Davis et al, 1977;Hughes et al, 1978a;Trautman, 1987;Gonzalez, 1987 andScott, 1988).…”

“…As the forage matures, nutrient content and digestibility diminish so that supplementation may be necessary to maintain efficient forage utilization and cow performance (Waller et al, 1972;Furr and Nelson, 1964;Davis et al, 1977). Oklahoma's native range during the winter usually dictates supplementation if optimum beef cow performance is desired (Nelson et al, 1952;Pinney et al, 1972;Trautman, 1987).…”

“…Davis et al (1977) The source of required energy should be an important consideration, particularly, during the first four or five calf crops. Merrill and Klopfenstein (1984) conducted two grazing studies (cattle on brome pasture or cornstalks) to study the effects of no supplement compared with feeding corn or soybean hulls.…”

“…Minimizing weight fluctuation year round should allow for more efficient rebreeding (Davis et al, 1977;Rakestraw et al, 1983). Cows that lost 20% of their full weight loss during the winter either required a longer time to return to estrus or more services for conception (Hughes et al, 1978b;Rakestraw et al, 1983).…”

“…While some weight and condition loss can be tolerated if initial body condition is adequate, the advantages of a 12-month calving interval provide incentives to stabilize cow weight changes during times of increased nutritional requirements (NRC, 1984;Lusby et al,1976a;Davis et al, 1977 Range cattle will consume an estimated 1 to 3% of body weight, depending on the nutrient content of the forage (Cordova et al 1978). Pacheco et al (1983) (Ellis, 1978;Van Soest, 1982).…”