Nutritional Challenges of Lactating Dairy Cattle in a Tropical Climate

Abstract

Nutrition is frequently cited as the primary challenge for milk production in the tropics. The quality of tropical forages is typically low and forage production is uneven distributed throughout the year due to rainfall patterns. The higher  ber and lignin concentrations common to tropical result in lower than desired supplies of nutrient and energy limiting milk production and decreasing reproduction ef ciency. To compensate, concentrates are frequently fed to improve nutrient balance. However, concentrate availability is limited in some areas and most concentrates are expensive compared with forage may limit or prevent their use by smaller producers. Utilization of improved grass varieties with lower lignin and  ber concentrations and higher digestibility would improve nutrient intake and supply which would support improved milk production. Legumes adapted to the tropics for grazing or as harvested forage often stimulate higher intake providing additional metabolizable energy and protein in support of higher milk production. Forage quality issues are compounded by heat stress which alters nutrient intake and metabolism of the dairy cow further limiting milk production and reproductive ef ciency. Physical modi cation of the environment is an effective means of reducing the heat load of the cow. Providing supplemental forage to the animals under shade can improve intake and yield of milk and components. As the genetic potential for milk production increases, dry matter intake increases producing additional metabolic heat. Adjusting the composition of diets fed to compensate for decreased intake is necessary to maintain ruminal function and nutrient balance to support milk production and reproduction. Producer adoption of improved practices to address these challenges is also in uenced by factors unrelated to actual nutrition such as cash  ow, labor availability and facility or equipment requirements and must be considered when promoting new technologies for speci c regions.