In vitro ruminal dry matter disappearance of selected waste papers

In vitro dry matter disappearances were determined for 11 paper sources and three complete rations containing 0, 10, and 20% newsprint. Inoculum was from an alfalfa hay-fed steer. Alfalfa hay, brome hay, and Solka Floc were reference substrates. Brown wrapping paper and brown cardboard had the highest dry matter disappearances of 90.8 and 77.8%; whereas four glossy or slick magazine papers had significantly lower values of 46.1, 45.1, 41.3, and 41.0%. Newsprint with black ink, without ink, and with colored inks had dry matter disappearances of 33.2, 32.6, and 26.5%, which were significantly lower than those of the glossy magazine papers. Lowest dry matter disappearances of 24.0 and 20.1% were from two magazine papers. The complete rations had 77.9, 80.1, and 81.8% dry matter disappearances for the 0, 10 and 20% paper rations. These data indicate substantial differences in digestibilities of various paper sources.