Effect of freezing on nutritional composition of forages

Abstract

The aim of this study was to evaluate the effect of freezing on nutritional composition of three forage species types: grasses, legumes and mixed perennial pastures. The study was carried out between November 2006 and January 2007 in the X Region of Los Lagos, Chile. Sixty six forage samples were collected from different farms within the region, and 33 of them were frozen at a temperature of -20 °C for a period of 15-17 days. Samples were analyzed for Dry Matter (DM), Crude Protein (CP), 
Metabolizable Energy (ME), Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), Soluble Protein (SP), Total Ashes (TA), in vitro digestibility (VD) and insoluble nitrogen in the NDF contents (NDIN). The effect of freezing was evaluated, blocking according to species with freezing time as a fixed factor. Treatments were statistically analyzed using complete randomized blocks and linear regressions between sets of fresh and frozen samples. The results showed that freezing affects the chemical composition of forages, particularly increasing the ADF and altering the NDIN given by a decrease in the crude protein concentration.