Effects of hybrid and maturity on performance and nutritive characteristics of forage maize at high latitudes, estimated using the gas production technique |
| |
Authors: | M Hetta Z MussadiqA-M Gustavsson C Swensson |
| |
Institution: | a Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden b Department of Rural Building and Animal Husbandry, Swedish University of Agricultural Sciences, SE-230 53 Alnarp, Sweden and Swedish Dairy Association, SE-223 70 Lund, Sweden |
| |
Abstract: | We evaluated effects of hybrid and advancing plant maturity on performance, chemical composition, and nutritional characteristics of whole plant forage maize as well as the relative contributions of its plant fractions at high latitudes. Three maize hybrids, Avenir (FAO 180), Isberi (FAO 190) and Burli (FAO 210), were grown in southern Sweden in a field experiment with a replicated complete randomized block design. Plants were harvested four times during maturation, and dry matter (DM) yield and DM as a proportion of fresh weight were recorded. Whole plants were separated into four morphological fractions representing stems, leaves, kernels and cobs and the contribution of each fraction to the DM of the whole plant was estimated. Plant material was subjected to chemical analysis followed by measurement of in vitro gas production (GP) in buffered rumen fluid and finally, by calculation of in vitro true digestibility of organic matter (OM) and neutral detergent fibre (aNDFom). The GP profiles were fitted to a first order kinetic model with a discrete lag. Parameters describing the GP profiles were used in a recently developed mechanistic two compartment rumen degradation model to estimate in vivo OM digestibility (OMD) and first order rate of degradation in the rumen. Hybrids were compared and effects of maturity were assessed by analysis of variance using DM concentration as covariate. There were differences (P<0.05) among the hybrids in DM yield and relative contributions of the plant fractions. Differences (P<0.05) in modelled in vivo digestibility of OM and rates of degradation also occurred among hybrids. Increased maturity caused a reduction in in vitro digestibility of aNDFom in all plant fractions (P<0.05), but increased the rate of rumen degradation of OM in the whole plant as evaluated from GP results. The DM yield had a quadratic relationship with increasing maturity, with maximum yield at a DM concentration of about 370 g/kg. In vitro GP can describe the nutritive characteristics of forage maize in relation to advancing maturity and increased maturity affected agronomic performance and plant composition as well as the nutritive characteristics of hybrids. |
| |
Keywords: | aNDFom neutral detergent fibre assayed with a heat stable amylase and expressed exclusive of residual ash CP crude protein DM dry matter EP escapable particles FAO food and agriculture organisation of United Nations GP gas production NEP non-escapable particles NDFD aNDFom digestibility OM organic matter OMD OM digestibility |
本文献已被 ScienceDirect 等数据库收录! |
|