Effects of previous grazing nutrition and management on feedlot performance of cattle

Management strategies designed to improve grazing animal performance can in fluence feedlot performance and carcass traits both positively and negative ly. In spite of the economic relevance of potential interactions between gr azing and finishing performance, controlled experiments evaluating integrat ed production systems are limited in number. Effects of grazing treatments can result from, or be overshadowed by, changes in gut fill, thus making it difficult to assign precise costs to different phases of production. Publi shed reports have considered the effects of stocking rate, duration of graz ing, forage characteristics, supplementation, and growth-promoting implants on subsequent finishing performance. Improvements in cattle performance at tributed to changes in stocking rate generally have been neutral to positiv e with respect to effects on finishing performance. Comparisons among forag es have led to the suggestion that forage species may contribute to differe nces in gastrointestinal fill of grazing cattle, thereby influencing gain a nd efficiency during the subsequent finishing phase. Creep-feeding suckling calves generally has increased preweaning performance but has had relative ly little influence on performance during the subsequent finishing phase. G rain supplementation of stocker cattle during the grazing period has improv ed grazing performance, but effects on subsequent feedlot performance have been inconsistent. Potential carryover effects from protein and mineral sup plementation also have been inconclusive. Lack of congruence among studies is puzzling but may be the consequence of highly varied production systems, differences in experimental procedures, and changes in gut fill or mass of internal organs. Based on the studies reviewed, the expression or absence of compensatory growth during the finishing phase appears to be related to the nutritional quality of forages utilized in the grazing period, with hig her quality forages tending to yield greater compensatory effects. The bulk of evidence with suckling cattle and stocker implants suggests that effect s on subsequent finishing performance are minimal. Attention is drawn to th e noticeable lack of research pertaining to integrated production systems. A more thorough understanding of the interactions among grazing nutrition a nd management, finishing performance, and carcass traits is needed to facil itate greater economic exploitation of these relationships.