Nutritional and energy value of corn silage on dairy farms in Eastern Croatia

The aim of this study was to determine the quality of corn silage as the dominant component in the diet of dairy cows in three counties of Eastern Croatia; Brod-Posavina, Osijek-Baranja, and Vukovar-Srijem. The practical part of the research included 25 dairy farms in each County in which corn silage was sampled and then analyzed. The monitored nutritional, fermentative, and physical indicators expressed as average values were satisfactory. Indicators of chemical composition: dry matter (DM) = 349 g/kg, crude protein = 71 g/kg DM, crude ash = 39 g/kg DM, crude fiber = 186 g/kg DM, acidic detergent fiber (ADF) = 212 g/kg DM, neutral detergent fiber (NDF) = 393 g/kg DM, acidic detergent lignin (ADL) = 17 g/kg DM, starch = 325 g kg DM, energy value expressed in net energy for lactation (NEL, MJ/kg DM) = 6.78, average digestibility of organic matter (dOM) = 75.8% and digestible neutral detergent fibers (dNDF)= 53.7%. Indicators of silage fermentation included the measurement of an average pH of 3.86, a concentration of lactic acid = 56.37 g/kg DM, and acetic acid of 20.68 g/kg DM. Physical indicator, determination of silage particle size distribution (three sieve system) recorded following values: sieve 1 = 7.1%; sieve 2 = 56.3%; sieve 3 = 24.8% and box at the bottom = 11.7%. Given the established statistical significance of the tested differences in average values for nine indicators of nutritional and energy value of corn silage between counties, it is possible to confirm that the quality of silage was better in Osijek-Baranja and Brod-Posavina counties than in Vukovar-Srijem County. Based on significant deviations in the minimum and maximum, and by determining a larger number of non-compliant samples in some indicators than the average values, it leads to the conclusion of uneven quality of silage in some producers.