Nurmikasvien koostumus, pepsiini-HCI-liukoisuus ja in vitro-sulavuus eri kasvuasteilla

Authors

• Maija-Liisa Salo Yliopiston kotieläintieteen laitos, Helsinki
• Anneli Nykänen Yliopiston kotieläintieteen laitos, Helsinki
• Riitta Sormunen Yliopiston kotieläintieteen laitos, Helsinki

DOI: https://doi.org/10.23986/afsci.71859

Abstract

The composition of meadow fescue and timothy was determined weekly during the first crop growth in two years and that of triploid red clover and couch grass in one year. The purpose was primarily to study at what growth stage these forages should be harvested for green meal, suitable to pigs and poultry. The recommended stage for harvesting is when the crop is 25—35 cm high (2-3 leaf stage) or 1 1/2—2 weeks before ear emergence. At this stage the crude protein content of grasses was, in the favourable spring, 24—28 %, and in the unfavourable spring, 16—21 % of dry matter. The pepsin solubility of protein was 80—85 % and the crude fibre content was below 20 %. Pepsin-HCI soluble organic matter was 50—53 % and in vitro soluble organic matter 80—82 % of dry matter. The quality of timothy deteriorated fastest and that of couch-grass slowest. The quality of red clover deteriorated much slower than that of the grasses; even three weeks after the meadow fescue was harvested the clover was still comparable to this in quality. In the unfavourable spring, the crude protein content of leaf stage grasses was 68 %-units lower, that of water soluble carbohydrates was as much higher, and the ash content about 2 %-units lower than in the favourable spring. During the most intensive growth the K-, Fe-, Mn- and Zn-contents of forages decreased sharply, and the P- and Ca-contents decreased slightly. The Mg-, Na- and Cu-contents were fairly constant during the whole growth period.