Utilizing gene suppression technology and hay storage techniques to improve forage quality and animal performance

Abstract

Utilizing technologies such as genetic modification and forage management techniques are two ways to improve forage quality. The objective of the first study in this thesis was to determine the differences in forage quality between reduced-lignin and conventional alfalfa. To test these differences, twenty-four Crossbred Angus heifers were selected to participate in this study and their performance was evaluated based on changes in BW, ADG, DMI, and G:F. In situ digestibility was determined using four ruminally cannulated Hereford cows. Hay samples were collected and used to determine forage quality and leaf-to-stem ratio. There were no differences (P > or = 0.05) in forage quality between treatments, except for DM (P = 0.01). Means did not differ by treatment for percent leaf (P = 0.06) but did differ for leaf-to-stem ratio (P = 0.04). There were no treatment or treatment by day interactions (P > or = 0.05) for BW, ADG, DMI, or G:F. There were no treatment or treatment by time interactions (P > or = 0.05) for in situ digestibility. Overall, the results of this study suggested no difference in forage quality between reduced-lignin and conventional alfalfa. Additionally, animal performance did not differ for crossbred Angus heifers consuming reduced-lignin or conventional alfalfa. The objective of the second study in this thesis was to quantify DM and forage quality losses associated with three different methods of outdoor round bale hay storage at two different sites in Montana. Large round bales consisting of 100% grass hay wrapped in plastic net wrapping were placed into one of four storage systems at both the Bozeman Agricultural Research and Teaching farm (BART) and the Northern Agricultural Research Center (NARC). The four storage systems were: single-stack (SS), pyramid (PYR), mushroom (MSH), and inside stored bales (INSIDE). Results indicated that DM and forage quality losses differed based on geographic location in Montana. This study suggested that DM and forage quality losses differ by location and that bale placement, rather than hay storage formation, is more important for changes in DM and quality for bales stored in Montana over the winter months.