WILLIAM N. MNENE¹, JERRY W. STUTH² and ROBERT K. LYONS³

¹Kenya Agricultural Research Institute, National Range Research Center-Kiboko, Makindu, Kenya
²Department of Rangeland Ecology and Management, Texas A&M University, College Station, Texas
³Department of Rangeland Ecology and Management, Texas A&M Research and Extension Center, Uvalde, Texas

Abstract

Effects of season, available herbage, and bush level on dietary composition and preference, plus dietary crude protein, digestible organic matter, and forage intake were determined for cattle in a Commiphora savanna of south-central Kenya. Grass dominated the diet selected at all bush and herbage levels. However, browse levels in the diet increased when grass consumption declined, particularly at low herbage levels (< 500 kg/ha) and during the dry-wet transition period. Principal grasses in the diet included Chloris roxburghiana, Cymbopogon pospochilii and Digitaria macroblephara, while Hermania alhiensis was the dominant browse in diets.
Season strongly affected dietary crude protein (CP) and energy intakes but had little effect on in vitro digestible organic matter. Dry season CP intake was below maintenance levels due to low forage CP. However, low herbage levels during the dry season were associated with below maintenance energy intake and reduced forage digestibility, while normal herbage levels were associated with energy intakes above maintenance and higher forage digestibility. Although CP and energy concentrations were relatively high during the dry-wet transition period, CP and energy intakes were at or below maintenance, respectively, due to depressed forage intake. Apparently, green herbage scarcity and inefficient browse harvestability restricted intake during the dry-wet transition season.