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Autumn closing date (CD) in intensive pasture‐based systems influences spring herbage availability. Little is known about the impact of earlier closing of swards in autumn on sward structure. A two‐year experiment was undertaken to investigate the impact of five CD on herbage production, leaf extension rate (LER), leaf senescence rates (LSR), sward free leaf lamina (FLL) content and the production and survival of tillers over winter and into spring. The five CD ranges were October 1–15 (CD1), October 16–30 (CD2), October 31––November 14 (CD3), November 15–29 (CD4), November 30–December 14 (CD5) and sward measurements were made on four measurement dates (MD): December 11 (MD1), January 6 (MD2), January 27 (MD3) and prior to spring defoliation (MD4). Thirty perennial ryegrass tillers were measured until the first defoliation in spring (average 1 March). Herbage mass was greatest in early CD and tillers had greater LER and LSR (4.6 and 4.5 mm tiller−1 day−1 respectively) compared to swards with a later CD (3.2 and 2.3 mm tiller−1 day−1 respectively). Early CD had greater parent and daughter tiller mortality than later CD (parent tiller mortality 1.1 and 0.3 ± 0.19 tillers; daughter tiller mortality 1.1 and 0.3 ± 0.27 tillers respectively). Early CD also had greater LER and LSR in daughter tillers (2.6 and 1.5 mm tiller−1 day−1, respectively) compared to late (1.5 and 0.5 mm tiller−1 day−1, respectively). Earlier closing of sward increased herbage mass in spring, however, there were negative implications, such as increased LSR and tiller mortality. [ABSTRACT FROM AUTHOR]

The diet of dairy cows in Ireland traditionally changes abruptly from predominantly pasture silage before calving to grazed perennial ryegrass immediately after calving. This potentially leads to problems with adaptation of microbes in the rumen with consequences of reduced intake and ultimately lower milk production. This experiment aimed to determine if introducing first-lactation dairy cows to perennial ryegrass herbage in the final weeks of pregnancy, thus eliminating a major dietary change at calving, could improve the adaptation process, potentially increasing dry matter intake (DMI) and milk production in early lactation. Three weeks prior to their expected calving date, 14 spring calving dairy cows were assigned to one of two treatments (n = 7): pasture silage pre-partum and perennial ryegrass herbage post-partum, or perennial ryegrass herbage both pre- and post-partum. Treatment diets were fed for 11 (±7) d pre-partum and for 14 (±0) d post-partum. For both treatments, DMI increased post-partum, but there was no difference between treatments, pre- or post-partum (5.9 and 8.8 kg DM/cow per day, respectively). There were no differences in milk yield or composition between the treatments. Body condition score declined following parturition but there were no differences between treatments. Plasma non-esterified fatty acids, glucose and β-hydroxybutyrate were also unaffected by treatment but did indicate a state of negative energy balance in early lactation. The results of this experiment suggest that pre-partum adaptation to perennial ryegrass herbage would not benefit milk production in first-lactation dairy cows in early lactation in Irish dairy farms employing this system. [ABSTRACT FROM AUTHOR]

Perennial ryegrass ( Lolium perenne L.) is one of the most popular grass species in Europe. It is commonly used for establishing the lawns in urban areas, where the salt stress is one of the major environmental conditions limiting its growth. The basic aim of this study was the detailed in vivo analysis of the changes in photosynthetic efficiency, induced by salt stress, of two lawn varieties of Perennial ryegrass and to find out the variety of better properties to create lawn on the soils contaminated with salt. Two lawn varieties of L. perenne L. were used: Nira and Roadrunner. The salinization was applied 8 weeks after sowing by adding NaCl in water solution (0, 0.15, and 0.30 M). The measurements were carried out 8 times: 0, 24, 48, 96, 144, 192, 240 and 288 h after salinization. Our results revealed that the disturbance of PSII function could easily be estimated by measuring chlorophyll a fluorescence and analyzing that signal by JIP-test. Our work allowed to identify various limiting parameters of photosynthetic efficiency of perennial ryegrass lawn varieties grown under salt stress conditions. This knowledge can allow for selection of plants with a higher potential photosynthetic efficiency (vitality) during salt stress conditions, that can be used successfully neighboring roads, where salt is applied. [ABSTRACT FROM AUTHOR]

Abstract: The biorefining of grass offers an opportunity to integrate primary production agriculture with the extraction of fibre. The study was aimed at developing protocols for processing ryegrass to determine fibre content and to generate visible and near infrared reflectance (Vis–NIR) calibrations for estimating fibre fineness with the aid of a new reference airflow method. The method for determining fineness of processed fibres has been adapted from flax fibre protocols. A Vis–NIR calibration using partial least squares (PLS) regression method was employed to generate models with a calibration set consisting of 85 samples obtained from fresh and ensiled grasses. The PLS model was successfully validated with 21 independent samples with a prediction error of 1.26dtex. An optimised PLS model (r 2 =0.86) consisting of 106 samples has been developed. The quality assurance protocols could be used for assessing fibre content and quality of silage, hay and fresh grass. [Copyright &y& Elsevier]

• Relationships between sum of temperatures, phenology and forage quality were explored. • Spring dynamic of 6 grasses were studied on 3 sites (altitude gradient) and 2 years. • The altitude influences the development and the dynamic of the quality of grasses. • Sum of temperatures was related to the among-site variability of forage quality. • Grasses phenology was related with the within-site variability of forage quality. This work addresses the dynamic of phenological development on mean stage weight (MSW), chemical composition, (ash, nitrogen (N), neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents, and pepsin-cellulase dry matter digestibility (PCDMD) for cultivars of six perennial grass species (timothy, ryegrass, cocksfoot, sheep's fescue, red fescue and meadow foxtail), during their first growth cycle. The study was performed over two years along 3 sites distributed along an altitudinal gradient. The dynamics of MSW, N, NDF, ADF and PCDMD for the species differed according to the environment. For a given sum of temperatures, at Clermont-Ferrand (CL; 350 m), MSW was delayed (note of 2.37) compared with Saint-Genès-Champanelle (SG; 850 m; note of 2.97) and Laqueuille (LA; 1100 m; note of 3.02). Consequently, the NDF and ADF contents were lower and the PCDMD value was higher in the cultivars established at CL (575 g/kg dry matter (DM), 287 g/kg DM and 0.64 respectively) than in those at SG (653 g/kg DM, 349 g/kg DM and 0.51 respectively) and LA (653 g/kg DM, 343 g/kg DM and 0.52 respectively). In all sites, and for the two years, the PCDMD content of timothy (0.60), ryegrass (0.63) and cocksfoot (0.59) cultivars were higher than that of sheep's fescue (0.47), red fescue (0.53), and meadow foxtail (0.51). The only exception was identified for CL site in the first year of the study, when the dynamic of PCDMD was similar for all cultivars. Sum of temperatures and MSW were closely related to nutritive value of forage, but neither indicator fully described the nutritive value of perennial grasses. [ABSTRACT FROM AUTHOR]

• Estimating dry matter intake (DMI) is crucial in grazing research to the understanding of animal performance and efficiency. • The n-alkane technique can successfully be used to estimate DMI in small ruminants, specifically sheep. • Estimation of DMI using the n-alkane technique is most accurate when animals are grazing swards <1600 kg DM/ha. • High herbage mass (HM) PRG contains higher indigestible fibre in the form of NDF which reduces DMI and digestibility. • Time of year (season) significantly affects DMI and thus the ability to estimate DMI using the n-alkane technique. Optimising nutrition for animals requires accurate estimates of feed intake. In research studies determining feed intake in grazing animals can be problematic with many methods requiring individual housing. The n-alkane technique whereby long chain alkanes are used as internal markers for predicting dry matter intake (DMI), facilitates estimation of feed intake from animals while grazing. The aim of this study was to determine the suitability of the n-alkane technique for estimating grass DMI from sheep grazing perennial ryegrass at three different herbage masses and across three seasons. A total of 242 in vivo DMI measurements were obtained from 50 Texel wethers across spring, summer and autumn from 2012 to 2014 using the total collection method; whereby herbage offered and refused plus total faeces produced was measured for each animal daily. Animals were offered perennial ryegrass ad libitium which was harvested at three different pre-grazing herbage masses (HM; low (<1600 kg DM/ha), medium (1601−2999 kg DM/ha), and high (>3000 kg DM/ha), across three separate seasons (spring, summer and autumn). All animals were dosed once daily with a C 32 n-alkane bolus for 12 days with a subsample of faeces collected for the final six days of each measurement phase. Lin's concordance correlations were used to examine the relationship between each n-alkane pair when predicting DMI. The Lin's concordance correlation coefficients between n-alkane estimated DMI using the ratio of C 31 / C 32 and C 33 / C 32 and measured DMI were 0.46 and 0.59, respectively. The r-squared value between measured DMI and n-alkane estimated DMI was 0.76 using the n-alkane pair C 31 / C 32 and 0.79 for the n-alkane pair C 33 / C 32. Herbage mass affected DMI with animals offered the low HM treatment having higher intakes (P < 0.05). Offering animals low and medium HM provided a more accurate estimate of DMI using the n-alkane technique. Thus, this research provides evidence that the n-alkane technique can be used as a reliable predictor of perennial ryegrass intake in sheep, when offered HM less than 2999 kg DM/ha. [ABSTRACT FROM AUTHOR]

Establishment of seeded 'Zenith' zoysiagrass (Zoysia japonica Stead.) in an existing sward of perennial ryegrass (Lolium perenne L.) is difficult, and chemicals arising from perennial ryegrass leaf and root tissue may contribute to establishment failure. Experiments were done to evaluate zoysiagrass emergence and growth in soil amended with perennial ryegrass leaves or roots, or after irrigation with water in which perennial ryegrass leaves or roots had previously been soaked. Compared to unamended soil, soil amended with perennial ryegrass leaves at 12% and 23% by weight reduced zoysiagrass seedling number 20% and 260%, respectively; root area and mass were reduced 50% when amendments comprised 12% of soil weight. Similar reductions in zoysiagrass seedling emergence and growth were observed in a second soil amendment study, regardless of whether perennial ryegrass was treated with glyphosate or not. Soil mixed with perennial ryegrass leaves, but not roots, at 12% by weight had a high soil conductivity (5.1 dS⋅m-1), which could have contributed to reduced zoysiagrass emergence and growth. More than 50% fewer zoysiagrass seedlings emerged and root mass was up to 65% lower when irrigated with water in which perennial ryegrass leaves or roots at 5, 10, or 20 g⋅L-1 were previously soaked for 48 hours. Zoysiagrass leaf area, and root length and area, were also lower when irrigated with water previously containing perennial ryegrass roots. Perennial ryegrass leaves and roots have the capacity to inhibit emergence and growth of 'Zenith' zoysiagrass seedlings, which could negatively affect stand establishment. [ABSTRACT FROM AUTHOR]

The relative contribution of tillers present in April and those appearing in consecutive periods in spring was assessed for perennial ryegrass cultivars in the three maturity groups (early, intermediate- and late-heading). Each group was represented by two diploid and one tetraploid cultivar each in plots in their third (2000) and fourth (2001) harvest years in three replicated blocks receiving an average of 325 kg N ha−1 and cut seven (in 2001) or eight (in 2000) times annually.‘Main’ tillers and their daughters were marked with colour-coded PVC-covered wire loops in early April as were daughters which appeared in consecutive periods between harvests, the loop colour identifying the period of origin of the tiller. Tillers were harvested at cutting height (5 cm) before the plots were harvested and the herbage from tillers with the same colour code bulked per plot. Tillers were identified retrospectively as‘reproductive’ if they had been decapitated at the previous harvest. Dry-matter yield was higher in the early than late-heading cultivars in April and early May but this was reversed in harvests in late May and June. The early heading group had a lower lamina content than the late-heading group during reproduction growth, both due to the reproductive tillers (mainly those which overwintered) having a lower leaf content and to their being fewer and smaller vegetative tillers during the reproductive phase than for the late-heading group. Turnover of tillers was high in spring due to decapitation of reproductive tillers and rapid post-flowering tillering. This was particularly pronounced in the early heading group which also had slightly more tillers marked in April which were subsequently decapitated than in the other maturity groups, i.e. 0·56 compared with 0·44 for the late-maturing group. Mean ratios of rate of death: rate of tillering for 3 years (1999–2001) for the early and late-heading groups were 0·8 and 0·4, respectively, for April–May and 1·1 and 2·4, respectively, for June indicating the different patterns in tiller turnover for the two extreme maturity groups. Information on tiller origin and contribution to yield can be used to refine tiller-based grass growth models. [ABSTRACT FROM AUTHOR]

Perennial ryegrass is widely used for overseeding dormant bermudagrass on golf courses and sports fields in Southeastern United States to provide green color and improved playability. Late spring and summer persistence of perennial ryegrass may decrease the quality of the bermudagrass turf and reduce its winter hardiness. To help solve this problem, we developed a strategy to activate a pro-herbicide within the transgenic perennial ryegrass plants and to cause self elimination of the plants. An E. coli argE gene was introduced into perennial ryegrass by the biolistic method, which resulted in four independently transformed green plants. The mRNA of argE gene was detected in three of the plants by RT-PCR. Perennial ryegrass plants expressing the argE transgene were selectively controlled upon application of a pro-herbicide, N-acetyl- l-phosphinothricin (or N-acetyl-PPT), since the N-acetylornithinase encoded by argE gene is able to convert N-acetyl-PPT to the herbicide phosphinothricin (PPT). The non-transgenic bermudagrass plants were unaffected by the treatment. This approach provides a means to selectively remove a group of transgenic plants without affecting other plants growing with them. [ABSTRACT FROM AUTHOR]

Accumulating herbage mass to facilitate the extension of the grazing season in autumn is commonly practised. The objective of the current study was to investigate the effect of accumulating varying target herbage masses (THM) in autumn and imposing different defoliation dates (DD), on herbage mass, sward quality and water-soluble carbohydrates in autumn and the subsequent spring. A 4 × 3 factorial split plot design was assigned with four THM (Low ≈ 500 kg·DM·ha−1, Medium ≈ 1500 kg·DM·ha−1, High ≈ 2000 kg·DM·ha−1 and Very high ≈ 3000 kg·DM·ha−1) and three DD (DD1—15 October, DD2—7 November and DD3—21 November), across two years. Measurements were carried out at each DD and in spring. Differences in sward quality were found between each THM on different DD. Sward quality reduced from DD2 to DD3 in the high THM (−13 g·kg−1 DM CP, p < 0.001). The very high THM had the lowest sward quality from DD1 (206 g·kg−1 DM CP, p < 0.001 and 787 g·kg−1 DM DMD, p < 0.05). This study has identified the defoliation date of THM in autumn as key to improving autumn management strategies for increased utilisation and sward quality. [ABSTRACT FROM AUTHOR]

The number and spatial distribution of perennial ryegrass (Lolium perenne L.) genotypes in 4 pastures were estimated by sampling single tillers from points 5 cm apart on an 11 7times; 11 grid. Three electrophoretic loci were used initially to determine the genotype of each tiller. Three 10-year-old sown swards contained at least 36--43 different genotypes per 0·25 m2 quadrat (10% of the number sown) while a 40-year-old pasture contained only 5 genotypes per 0·25 m2 quadrat. The cut sward had a greater proportion of its area occupied by a few large genotypes than the swards grazed by sheep or cattle. The importance of age, management, and other factors influencing genotypic diversity in swards is discussed. [ABSTRACT FROM AUTHOR]