The effect of different levels of spring grass supply and stocking rate on the performance and intake of cows in early lactation

End of project reportGrazed herbage can supply nutrients to dairy cows at a lower cost than alternative feeds (Shalloo et al., 2004). Therefore, the objective of pasture-based systems must be to maximize the proportion of grazed grass in the diet of the dairy cow (Dillon et al., 2005). The extension of the grazing season into the early spring period can be facilitated by ceasing grazing of pastures earlier in autumn which allows grass to accumulate, thereby ensuring an adequate herbage supply in early spring when animal demand exceeds grass growth/supply (O’Donovan, 2000). Grazing pastures in early spring has previously been shown to increase herbage utilization and condition swards for subsequent grazing rotations (O’Donovan et al., 2004; Kennedy et al., 2006)

A Comparison between Simulated Grazing, 2-Cut and 3-Cut Silage Management on the Performance of \u3cem\u3eLolium perenne\u3c/em\u3e L.

Internationally, the majority of grass cultivar evaluation protocols test the performance of cultivars under cutting managements with little or no exposure to animal stresses such as treading and plant pulling. In addition, the majority of these protocols test cultivars under 2 or 3 cut silage systems. Gilliland and Mann (2000) reported a difference in cultivar ranking between years and also between management systems when a severe (simulated grazing to 3 cm height) or lax (6 cm height) defoliation was applied to perennial ryegrass (Lolium perenne L.) cultivars in plot trials. Internationally, many evaluation protocols use only one management system within the protocol, whereby defoliation height is constant. If the protocol applied is not similar to the grazing manage-ment imposed at farm level, then it is unclear if the protocol can identify the cultivars which are most suitable to a particular production system

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

peer-reviewedThe grass plant comprises leaf, pseudostem, true stem (including inflorescence) and dead material. These components differ in digestibility, and variations in their relative proportions can affect sward quality. The objective of this study was to determine the change in the proportion and organic matter digestibility (OMD) of leaf, pseudostem, true stem and dead components of four perennial ryegrass cultivars (two tetraploids: Astonenergy and Bealey and two diploids: Abermagic and Spelga) throughout a grazing season. The DM proportions and in vitro OMD of leaf, pseudostem, true stem and dead in all cultivars were determined during ten grazing rotations between May 2011 and March 2012. There was an interaction between rotation and cultivar for leaf, pseudostem, true stem and dead proportions. In May and June, Astonenergy had the highest leaf and lowest true stem proportion (P pseudostem > true stem > dead. Bealey had the highest combined leaf and pseudostem proportion 0·92, which explains why it had the highest OMD. In this study, the tetraploid cultivars had the highest leaf and pseudostem proportion and OMD. For accurate descriptions of a sward in grazing studies and to accurately determine sward morphological composition, pseudostem should be separated from true stem, particularly during the reproductive stage when true stem is present

Improving student learning through virtual means

Virtual Patients are used in medical education but research evidence to guide their use is still modest. This research was designed to test the hypothesis that the use of Virtual Patients does not significantly improve the development of clinical knowledge, professional identity and reflective skills in undergraduate medical students. The research questions addressed were: (i) Based on an evaluation of current undergraduate training, is there a need to supplement the traditional paediatric curriculum to ensure that all students receive equivalent educational experiences?: (ii) Are Virtual Patients an effective learning tool in undergraduate education? Following an evaluation of the current curriculum, an online Virtual Patient model, and an instrument for assessing it, were developed and assessed in 181 undergraduate medical students and 25 postgraduate trainees. A multi-level mixed method approach (logbook reviews, focus groups, questionnaires, MCQs, problem-based questions, professional dilemma cases and semi-structured observer ratings) was used to assess the impact on clinical knowledge, professional identity and reflective capacity. The current curriculum did not provide adequate exposure to essential infrequent cases in clinical practice and students were not receiving equivalent educational exposure. Virtual Patients provided an acceptable learning tool and the measure developed for evaluating their impact was practical, reliable and valid. Compared to the traditional curriculum alone, exposure to Virtual Patients significantly improved short-term learning and long-term knowledge retention. Providing students with written feedback during the module improved their learning about professional norms and their ability to apply such norms to clinical scenarios. A semi-structured, observer-rated instrument was shown to have acceptable psychometric properties as a measure of students’ responses to videos designed to evoke reflection. Female, postgraduate and academically higher performing students were significantly more likely to engage in deeper reflection. Guided reflection improved students’ ability to reflect, but may not encourage students who do not have a natural tendency to reflect, to engage in the process. In conclusion, Virtual Patients are acceptable learning tools for improving clinical learning while simultaneously promoting the development of professionalism and reflective abilities in undergraduate medical students

Cultivar Influences Milk Production of Grazing Dairy Cows

Perennial ryegrass is considered one of the most important forage grass species used in temperate ruminant animal production systems. Maximizing milk production from grazed grass is a major objective of pastoral-based dairy systems. While DM yield is an important trait, it fails to define the ultimate value of a grass cultivar, which is its potential to improve animal performance from a pasture sward (Reed 1994). The majority of cultivar evaluation trials are conducted under cutting, so therefore inferior cultivars from an animal production perspective may not be identified until commercialisation when animals graze a pasture sward. Reed (1978) reported that ryegrass pastures of similar digestibility can have different animal production responses depending on the season. Without exposure to animal production trials, practical differences between cultivars under field conditions may not be detected. The objective of the current study was to evaluate the effect of four perennial ryegrass cultivars with different sward characteristics on milk yield, milk composition and dry matter intake (DMI) of lactating dairy cows during the spring and mid-season period

Dry Matter Yield of Perennial Ryegrass Cultivars under Mechanical Cutting and Animal Grazing

Perennial ryegrass evaluation trials are essential to identifying and promoting the most productive cultivars for use at farm level to maximise sward productivity (Grogan and Gilliland 2011). Cultivar testing is predominantly conducted under simulated grazing trials to predict dry matter yield (DMY) performance under animal grazing. Previous studies have shown a high correlation in DMY between these two defoliation methods (Camlin and Stewart 1975; Creighton et al. 2010). In contrast, Binnie and Chestnutt (1991) demonstrated that swards grazed by animals had higher DMY performance than those exposed to simulated grazing managements. Animal pressures such as pulling, treading and nutrient return are not present in a simulated grazing management. The objective of this study was to determine if a relationship exists between the DMY of perennial ryegrass cultivars exposed to mechanical cutting compared to animal grazing