Botanical Composition of the Diet of Grazing Cows During the Dry Season in a Subtropical Region of Mexico

Introduction of livestock into tropical and subtropical forest areas has displaced the orig-inal forest vegetation. Posterior surge of secondary vegetation has served as a source of al-ternative forage to cattle during scarcity periods. The objective of the study was to determine the botanical composition of the diet (BCD) and the productive performance of lac-tating Brown Swiss cows during the dry season. The BCD was determined through microhistological analysis of fecal samples of grazing cows. Grazing areas were sampled to determine morphological and botanical composition (BCP). Forages were sampled to determine their chemical composition. Cow's productive variables were recorded during March, April, and May of 2012. The BCP and BCD consisted of Cynodon plectostachyus and the woody species were Vachellia farnesiana, with smaller proportions of Pithecellobium dulce, Guazuma ulmifolia, and Ficus sp. These forages contributed with 63, 48, and 47% of the dry matter, metabolizable energy, and metabolizable protein requirements of the cows. Therefore, it is concluded that alternative forages contributed significantly to the nutri-tional requirements during periods of pasture scarcity. Understanding the botanical composition of the diet of grazing cows allows for the development of management strat-egies based on the efficient use of local resources.