Effects of levels of tallow on in situ degradability of soybean meal and tifton hay {Cynodon dactylon (L.) Pers.} in dry cows

Abstract

This experiment was carried out to evaluate the effects of tallow supplementation by means of in situ degradability. Three diets, control (without tallow supplementation), diet with 3% or diet with 6% of tallow on a dry matter basis, all with 60% of roughage. The experimental design was a Latin Square 3 x 3, using six rumen canulated heifers (480 kg body weight). The experiment had three periods of 28 days, being the first 21 for diet adaptation which was composed of Tifton hay (Cynodon dactylon) and a mixture of concentrate. In situ degradability assay was run from day 21° to the 28°. Incubation times were 6; 12; 24; 48; 72 and 96 hours for hay dry matter and neutral detergent fiber and 1,5; 3; 6; 12; 24 and 48 hours for soybean meal dry matter and crude protein. The time zero was used to evaluate the soluble fraction. As tallow in the diet increased, there was a decreased in the hay DM and NDF degradabilities and increase in the soybean meal DM and CP degradabilities.