The effects of autumn closing date on sward leaf area index and herbage mass during the winter period

Abstract

The provision of grass for early spring grazing in Ireland is critical for spring calving grass-based milk production systems. This experiment investigated the effect of a range of autumn closing dates (CD), on herbage mass (kg DM ha )1 ), leaf area index (LAI) and tiller density (m )2 ) during winter and early spring. Thirty-six grazing paddocks, closed from 23 September to 1 December 2007, were grouped to create five mean CD treatments -

The variation in morphology of perennial ryegrass cultivars throughout the grazing season and effects on organic matter digestibility

“…Senescent material accumulates over the winter period (Hennessy et al ., ; Ryan et al ., ). This resulted in an increase in dead proportion in mid‐February compared with mid‐October with the proportion of dead in mid‐February similar to that reported by Hennessy et al .…”

The effects of simulated summer‐to‐winter grazing management on herbage production in a grass–clover sward

“…Therefore, the date of final grazing in winter strongly influences the start of grazing in spring on a per‐paddock basis. Under these conditions, the first paddock grazed in February would have been last grazed in early‐to‐mid‐October (Hennessy and Kennedy, ; Ryan et al ., ). Furthermore, excessively wet soil conditions limit both first and final grazing dates on most Irish dairy farms (Creighton et al ., ).…”

“…Another important aspect of grazing management during autumn–winter is the final grazing (closing) date. This is the primary determinant of pre‐grazing herbage mass (HM) in early spring (Roche et al ., ; Hennessy et al ., ; Ryan et al ., ). However, carrying swards with high HM for long periods over winter has been found to increase shading of clover leaves and stolon growing points, which can result in lower sward clover contents in early spring (Laidlaw and Stewart, ; Laidlaw et al ., ).…”

Effect ofLolium perennesward density on productivity under simulated and actual cattle grazing

“…Dried samples were milled through a 1‐mm screen, with herbage dry‐matter digestibility and crude protein concentration determined using the near infrared reflectance spectroscopy method (Foss UK Ltd., Warrington, UK). Sward tiller number (population density) was assessed at the end of the grazing season by counting tiller numbers in three 10‐cm 2 turves taken from each plot as described by Ryan et al. (2010).…”