In sacco macromineral release from selected forages

Abstract

An in sacco technique was used to measure the release of Mg, Ca, Na, K from six forages &minus; lucerne hay from the 1^st and 2^nd cut (LH1 and LH2), orchard grass hybrid Rela (GR) and hybrid Niva (GN), grass silage (GS), red clover silage treated with Feedtech (CSFT) and/or with Kofasil (CSKO). The forages differed in the content of macrominerals (Ca 15.82&minus3.66 g/kg DM; Mg 3.68&minus;1.46 g/kg DM; Na 0.20&minus;3.02 g/kg DM; K 21.57&minus;34.79 g/kg DM), and large differences (<i>P</i> < 0.01) were also in the element release in the rumen between experimental forages. The lowest DM effective degradability was determined for grass forages (49.5%&minus;51.5%) and forages from legumes had higher degradability (62.9%&minus;67.1%). The extent of disappearance of macroelements was also higher from LH1, CSFT, CSKO than from G and GS. The release of individual elements in all incubation times is expressed very well by cubic polynomials. Maximum disappeared portions of individual minerals from forages are as follows: Ca 86.3% and Mg 93.2% from CSFT, Na 98.7% from GN and K > 98% from all feeds. Potassium solubility is rapid and is not affected by the incubation time.