Efeito da variação na composição do micélio sobre a predição de desempenho predita pelo nasem 2021 em bovinos leiteiros

Abstract

The use of the co-product mycelium in the diet of dairy cows is still limited due to the scarcity of consistent information on its chemical composition, as well as these factors can affect the prediction of performance of dairy cattle using nutritional models, such as NASEM (2021). In this sense, the objective was to evaluate the effect of the variation in the chemical composition of the mycelium on milk production estimated by the NASEM model (2021). The mycelium samples were collected in six different loads at the Dairy Cattle Sector (SEBOL) of the Glória Experimental Farm and the analyzes were carried out at the Bromatoloa and Animal Nutrition Laboratory (LABAN). In each load, ten subsamples were collected to form a composite sample, divided into three replications. The contents of dry matter (DM), mineral matter (MM), crude protein (CP), ether extract (EE); neutral detergent insoluble fiber (NDF) and acid detergent insoluble fiber (FDA). The milk production prediction model used was NASEM (Dairy 8, 2021). Three scenarios of mycelium use in confinement systems were used, with different levels of milk production (PL). Scenario 1 (PL 25 L and 11% mycelium inclusion); Scenario 2 (PL 25 L and 25% mycelium inclusion) and scenario 3 (PL 40 L and 7% mycelium inclusion). For data analysis, descriptive statistical tools were used, such as measures of central tendency (mean), dispersion (minimum and maximum values) and the coefficient of variation (CV). There was a high VC in the levels of PB, MM, EE, NDF, CNF among the loads and a low VC for DM. In addition, it was found that the highest level of mycelium inclusion (25%DM) caused a higher VC in the LP predicted by the metabolizable protein. It is concluded that mycelium has the potential to compose the diet of dairy cows, being a viable and interesting alternative to reduce feed costs. However, its use should be preceded by periodic bromatological analyses and careful formulation in the diets, since the variability of its nutritional composition can compromise the predictions of productive performance when used at higher levels of inclusion (25%) in dairy cows producing 25 liters. On the other hand, diets with lower levels of mycelium inclusion (11%) showed little variation in milk yield estimates based on both metabolizable protein and net energy, indicating greater nutritional stability and lower sensitivity to fluctuations in the chemical composition of the ingredient.