IMPACT OF HIGH FORAGE GROWING SYSTEMS ON FINISHING PERFORMANCE AND COMPENSATORY GROWTH (BEEF CATTLE, RUMINANT, LAMB, SHEEP)

Effects of high forage growing systems on subsequent finishing performance and compensatory growth by cattle and lambs were investigated. In experiment one, heifers wintered on cornstalks or wintered on cornstalks and summered on grass gained faster and more efficiently than heifers finished soon after weaning. Heifers wintered on cornstalks and summered on grass gained faster, consumed more feed and were more efficient than cattle finished immediately after wintering on cornstalks. Heifers responded to higher protein by gaining faster and more efficiently when fed corn diets throughout the finishing phase, but not when corn silage diets were fed before the corn diets. The longer the growing period, the greater was carcass weight at a common fat (12th rib) endpoint. Increased intake accompanied compensatory gain and was affected more by animal age and(or) pre-finishing nutrition than by animal weight.;Lambs were used in a third experiment to determine effects of growth rate on body composition and the subsequent changes in body composition during compensatory growth. Increasing growth rate resulted in fatter lambs with less protein at an equal empty body weight. As lambs grew slower the compensatory response was greater for rate of gain and feed efficiency during the finishing period. Compensatory growth occurred in two stages (1) increased rate of protein deposition followed by (2) increased rate of fat deposition. These differences were reflected in whole body composition.;In experiment two, summer rate of gain decreased as winter growth rate increased (r = -.61); but, no interactions between winter growth rate and summer grazing existed for finishing performance. Cattle from high forage systems, compared to cattle from the high grain system, consumed more feed and exhibited compensatory growth during the finishing period. Compensatory gain was greater if cattle were finished immediately after wintering and not allowed to graze summer grass before finishing. Increasing length of the growing period resulted in heavier carcass weights at a common fat (12th rib) endpoint.