perennial ryegrass

Bijeenkomst: EGF2015
Auteur: Goliński P. and Golińska B.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
The objective of this work was to analyse the differentiation of selected cultivars within five pasture grass species with regard to leaf tensile strength (LTS). The investigations were carried out in 2011- 2012 on plant material obtained from two cultivar testing experiments, in which Dactylis glomerata (10 cultivars), Festuca arundinacea (10 cvs), Festuca pratensis (15 cvs), Lolium perenne (16 2× and 15 4× cvs) and Phleum pratense (10 cvs) were analysed. LTS was estimated on fully developed leaf blades using a prototype testing stand for measuring tensile strength of biological material, designed on the basis of a subassemblies of the Höttinger Baldwin Messtechnik (HBM) Company. The fresh matter and dry matter weight, width and specific leaf area of leaf blades were also determined. The LTS of investigated species ranged from 4.06 N (L. perenne 2×) to 12.46 N (D. glomerata). The differentiation of cultivars within species was also high and statistically significant. Performance of precise tensile strength measurements of leaf blades could be a helpful plant breeding tool for the development of improved pasture grass cultivars and selection of appropriate components in seed mixtures, particularly in high output dairy farming systems.

Bijeenkomst: EGF2015
Auteur: Garry B., Kennedy E., Baumont R., Boland T.M., Wright M.M., O’Donovan M. and Lewis E.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
Pre-grazing herbage mass (PGHM) affects grass quality and intake. Higher PGHM swards usually have lower dry matter intake (DMI) and in vitro dry matter digestibility (DMD) than lower PGHM swards, leading to reduced performance in lactating dairy cows. In vivo digestibility experiments involving cows are often laborious and expensive and, as a result, sheep are often used instead. The objective of this experiment was to compare the in vivo DMD of perennial ryegrass (Lolium perenne L.) at high and low PGHM in lactating dairy cows and wether sheep. A Latin-square design experiment was repeated twice (TS1 (April-May) and TS2 ( July-August)) using eight wether sheep and eight spring-calving lactating dairy cows to determine the in vivo DMD of two different PGHM swards (1,700 kg dry matter (DM) ha‑1 (low mass; LM) and 4,000 kg DM ha‑1 (high mass; HM)). There were no interactions between PGHM, animal species and TS. The in vivo DMD of perennial ryegrass reduced from LM to HM and from TS1 to TS2. There was a tendency for cows to have lower in vivo DMD of perennial ryegrass than sheep. The greater in vivo DMD of LM compared to HM may be due to the greater proportion of leaf and lower true stem proportion in LM. As there were no interaction effects on in vivo DMD, sheep DMD and cow DMD are similar to each other across all PGHM and all seasons.

Bijeenkomst: EGF2015
Auteur: McDonagh J., McEvoy M., Gilliland T.J. and O’Donovan M.
ISBN: 978-9090-289-61-8
Jaar van uitgifte: 2015
Producttype: Paper
Perennial ryegrass (Lolium perenne) is the most widely used ryegrass species for high-output pasture based dairy farms in Europe. Repeated selective breeding has enhanced dry matter (DM) productivity potential, elevated nutritive value and provided a large diversity of varieties adapted to variant growing conditions and farming practices. With renewed interest in white ryegrass-clover swards mixtures, there is a concern that sward interactions between perennial ryegrass varieties and white clover will have a significant effect on the dry matter yield performance of a recommended grass variety. The aim of this study was to establish if perennial ryegrass varieties re-rank in DM yield when sown with/without white clover at two nitrogen applications under intensive grazing. Eight perennial ryegrass varieties were sown with (+C) /without (-C) white clover. Swards received two levels of nitrogen 250 (HN) and 100 (LN) kg N ha‑1. Treatments were HN+C, HN-C, LN+C and LN-C. A significant nitrogen by clover interaction occurred because LN-C gave the lowest yield, but although high nitrogen increased both the with and without clover treatments, the highest yielding treatment was LN+C. Grass variety had a significant effect (P>0.001) on DM yield, but the ranking of the ryegrass varieties was unaffected by the imposed treatments and so represented a robust estimation of the relative DM production potential of each ryegrass variety. The inclusion of clover also did not affect the relative performance of the ryegrass varieties, indicating that any inter-species competitive interactions were not variety specific.