Nutritive Value of Damp Rice Straw and its Feeding Effect on Aflatoxin Transmission into Cows Milk

Abstract

The experiment was carried out to determine the nutritive value of different level of fermented rice straw as well as to detect the level of mycotoxin contamination and its transmission into cow`s milk. Rice straw was collected from selected area based on degree of fermentation i.e. high fermented, low fermented and unfermented rice straw. Similarly, milk samples were collected from cows fed rice straw of the same area. Results showed that, DM, CF and NFE were significantly (P<0.05) lower in high fermented rice straw compared to low and unfermented straw. The in vitro digestibility of OM of high fermented rice straw were significantly (P<0.01) lower than unfermented straw (40.69 vs. 41.55%). However, ME content of rice straw was similar (P>0.05) irrespective of level of fermentation. The effective degradability of DM for high fermented straw was significantly (P<0.05) lower than unfermented straw (13.03 vs. 19.26%). However, the effective degradability of CP of high fermented straw was significantly (P<0.05) higher than unfermented straw (17.10 vs. 10.83%). Chemical analysis of fermented and unfermented rice straw did not show detectable level of aflatoxin. However, milk samples collected from some area showed certain level of aflatoxin M<sub>1</sub> (0.001 μg/kg to 0.006 μg/kg). These findings clearly show that, fermentation of rice straw due to dampness reduces its soluble nutrients, in vitro digestibility and degradation of DM in situ, however, increases the effective degradability of CP. Dampness also leads to the transmission of aflatoxin M<sub>1</sub> from fermented straw to cow`s milk in low level.