Estabilidade aeróbica de silagens de alfafa elaboradas em dois estádios fenológicos

Abstract

Alfalfa is one of the most important forages due to its productivity, protein quality, palatability and digestibility, being a great roughage for dairy cattle. However, the supply to animals in the form of grazing is subject to variations in alfalfa quality and quantity due to plant developmental stages and also climatic variations that may cause shortage of forage supply. Thus, it is important to preserve the forage to maintain its high nutritional levels. Silage is an important option for bulky conservation. Given this, this research aims to evaluate the nutritional changes of alfalfa silage elaborated in two phenological stages E1 and E2 in order to find the balance between nutritional quality and aerobic stability after desilting. The alfalfa silage was implanted in an area in the city of Salvador das Missões - RS. After opening the silos, the temperature inside the silo, the pH, the bromatological composition were evaluated: Dry Matter (MS), Mineral Matter (MM), Total Digestible Nutrients (NDT), Neutral Detergent Fiber (NDF), Acid Detergent Fiber (FDA) and Crude Protein (CP) and nutrient losses occurring after periods of aerobic exposure. Evaluations were performed at the time of silo opening, considered hour 0 and after 24, 48, 72 and 96 hours of aerobic exposure. The results showed that even after the rapid disruption of aerobic stability, around 24 hours, this did not affect the nutritional quality of alfalfa silage in both elaboration stages. Achieving high levels of PB and NDT. There were low levels of NDF and ADF. Losses totaled 4.32% DM, 1.22% CP and 3.09% TDN in the silage elaborated in stage 2, after 96 hours of aerobic exposure, with statistical difference in this stage regarding the aerobic exposure period.