Integration of complementary forage with native range for efficient beef production in the Sandhills of Nebraska

Abstract

A winter supplementation study was conducted during two consecutive winters in order to evaluate high quality hay produced in subirrigated meadows in the Sandhills of Nebraska. Ninety-six multiparous crossbred cows were used each year, 24 cows/treatment subdivided to graze in two different pastures. In both winters Control (C) cows lost body weight and body condition, while cows supplemented with either high quality meadow hay (H), soybean meal supplement (S), or H + S maintained or improved body weight and body condition (P $<$.05). Range intake and digestibility were not enhanced by protein supplementation, and pregnancy rate, calving date, and birth and weaning weight were not affected by supplementation either (P $>$.05). In a study using ruminally-fistulated steers conducted to evaluate the effects of supplementing native range hay (C) with either H or S on ruminal kinetics, particulate passage rate (kp, %/h) of Yb-labeled C was not affected by supplementation with either (P $>$.05). However, particulate kp of Er-labeled H or S was different, H had a lower kp and higher total tract retention time than S (P $<$.05). A metabolic study was conducted in order to evaluate native range hay (C) supplementation with four different levels (10 to 40% of DM intake) of H (C10, C20, C30, and C40). Five ruminally and duodenally-fistulated steers were used in a 5 x 5 Latin square, the steers were fed at 1.5% of BW (DM basis). Nitrogen intake and total tract N digestibility increased linearly with H additions (P $<$.05); total N flowing to the duodenum was improved by supplementation, as well as microbial N synthesis (P $<$.05). Microbial efficiency was maximized at 1.37 g of microbial N/100 g of total tract apparently digested organic matter. It was achieved at 13.4% level of H added and equals 7.2% dietary CP, therefore rumen degradable protein requirements were estimated to be 4.3% (organic matter basis). These results all indicate that high quality meadow hay produced in subirrigated meadows if sufficiently high in CP is a good alternative to protein supplement pregnant beef cows grazing winter range. However, attention to alternative more economic ways to use subirrigated meadows must be considered.