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

The introduction of livestock into tropical and subtropical forest areas has displaced the original forest vegetation. Posterior surges of secondary vegetation have served as a source of alternative forage to cattle during scarcity periods. The objective of this study was to determine the botanical composition of cows' diet (BCD) and the productive performance of lactating Brown Swiss cows during the dry season. The BCD was determined through microhistological analysis of faecal samples of grazing cows. Grazing areas were sampled to determine morphological and botanical composition (BCP). Forages were sampled to determine their chemical composition. Cows' productive variables were recorded during March, April, and May of 2012. The BCP and BCD consisted of <i>Cynodon plectostachyus</i> and the woody species included <i>Vachellia farnesiana</i>, with smaller proportions of <i>Pithecellobium dulce</i>, <i>Guazuma ulmifolia</i>, and <i>Ficus</i> sp. These forages contributed 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 addressing nutritional requirements during periods of pasture scarcity. Understanding the botanical composition of the diet of grazing cows allows for the development of management strategies based on the efficient use of local resources.