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

Gastrointestinal tract size, total-tract digestibility, and rumen microflora in different dairy cow genotypes

peer-reviewedThe superior milk production efficiency of Jersey (JE) and Jersey × Holstein-Friesian (JE × HF) cows compared with Holstein-Friesian (HF) has been widely published. The biological differences among dairy cow genotypes, which could contribute to the milk production efficiency differences, have not been as widely studied however. A series of component studies were conducted using cows sourced from a longer-term genotype comparison study (JE, JE × HF, and HF). The objectives were to (1) determine if differences exist among genotypes regarding gastrointestinal tract (GIT) weight, (2) assess and quantify whether the genotypes tested differ in their ability to digest perennial ryegrass, and (3) examine the relative abundance of specific rumen microbial populations potentially relating to feed digestibility. Over 3 yr, the GIT weight was obtained from 33 HF, 35 JE, and 27 JE × HF nonlactating cows postslaughter. During the dry period the cows were offered a perennial ryegrass silage diet at maintenance level. The unadjusted GIT weight was heavier for the HF than for JE and JE × HF. When expressed as a proportion of body weight (BW), JE and JE × HF had a heavier GIT weight than HF. In vivo digestibility was evaluated on 16 each of JE, JE × HF, and HF lactating dairy cows. Cows were individually stalled, allowing for the total collection of feces and were offered freshly cut grass twice daily. During this time, daily milk yield, BW, and dry matter intake (DMI) were greater for HF and JE × HF than for JE; milk fat and protein concentration ranked oppositely. Daily milk solids yield did not differ among the 3 genotypes. Intake capacity, expressed as DMI per BW, tended to be different among treatments, with JE having the greatest DMI per BW, HF the lowest, and JE × HF being intermediate. Production efficiency, expressed as milk solids per DMI, was higher for JE than HF and JE × HF. Digestive efficiency, expressed as digestibility of dry matter, organic matter, N, neutral detergent fiber, and acid detergent fiber, was higher for JE than HF. In grazing cows (n = 15 per genotype) samples of rumen fluid, collected using a transesophageal sampling device, were analyzed to determine the relative abundance of rumen microbial populations of cellulolytic bacteria, protozoa, and fungi. These are critically important for fermentation of feed into short-chain fatty acids. A decrease was observed in the relative abundance of Ruminococcus flavefaciens in the JE rumen compared with HF and JE × HF. We can deduce from this study that the JE genotype has greater digestibility and a different rumen microbial population than HF. Jersey and JE × HF cows had a proportionally greater GIT weight than HF. These differences are likely to contribute to the production efficiency differences among genotypes previously reported

Comparing Drying Protocols for Perennial Ryegrass Samples in Preparation for Chemical Analysis

Diet formulation for animals requires accurate estimation of feed nutritive value. In order to determine the nutritive value of grass, the moisture in the samples must be removed, with minimum damage to cell structure, and then the dried samples milled, prior to chemical analysis. Generally samples are oven dried. The aim of this study was to verify if differing drying protocols gave diverging results when drying grass samples. The drying protocols investigated were 40°C for 48 hours, 60°C for 48 hours and 95°C for 15 hours in forced convection ovens. Four perennial ryegrass samples were cut to 4 cm from ground level on three occasions in 2012. On each occasion the four grass samples were mixed together thoroughly and divided into four replicates. Each replicate was divided into three sub-samples to give one 100 g-sample per drying treatment. At regular intervals the samples were removed from the oven and the weight recorded. The data were analysed using a mixed model repeated measures procedure in SAS. Time (hours) was used as the repeated measure. A separate dataset of 12 grass samples were dried using both the 40°C and 60°C protocols and then chemically analysed. This dataset was analysed using PROC GLM in SAS. Samples were assumed dry when there was no significant difference in weight between times. All drying protocols gave a similar final dry matter of approximately 156 g/kg. All drying protocols did dry the grass samples adequately as samples dried at 40°C and 60°C were not significantly lighter after 24 hours and samples dried at 95°C were not significantly lighter after 15 hours. There were no differences in ash or crude protein concentration of the samples dried using the 40°C and 60°C protocols. There were differences in the organic matter digestibility, neutral detergent fibre and acid detergent fibre concentrations between the grass samples dried using the different drying protocols

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

Do Different Breeds of Dairy Cow Differ in Their Ability to Digest Perennial Ryegrass?

Grazed grass is the cheapest feed source available for ruminant production systems in temperate climates (Finnernan et al. 2010) accounting for 70% and 90% of the diet of dairy cows in Ireland and New Zealand, respectively. Successful operation of grass-based dairy systems is based on achieving large intakes of high quality grass and efficiently converting it into high value milk solids (Prendiville et al. 2010). Prendiville et al. (2009) identified production efficiency differences between Holstein Friesian (HF) and Jersey (J) cows. They found that J had higher milk solids output per 100 kg bodyweight than HF. The aim of this study was to identify if HF, J and crossbred (J×HF) cows differ in their ability to digest perennial ryegrass

The Variation in Morphological Fractions of Perennial Ryegrass Cultivars throughout the Grazing Season and Subsequent Impacts on Organic Matter Digestibility

The grass plant is comprised of leaf blades, leaf sheath (pseudostem), true stem and dead material each differing in digestibility and their relative proportions can impact significantly on 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 fractions of four perennial ryegrass cultivars throughout a grazing season

Developing a sustainability science approach for water systems

We convened a workshop to enable scientists who study water systems from both social science and physical science perspectives to develop a shared language. This shared language is necessary to bridge a divide between these disciplines’ different conceptual frameworks. As a result of this workshop, we argue that we should view socio-hydrological systems as structurally co-constituted of social, engineered, and natural elements and study the “characteristic management challenges” that emerge from this structure and reoccur across time, space, and socioeconomic contexts. This approach is in contrast to theories that view these systems as separately conceptualized natural and social domains connected by bi-directional feedbacks, as is prevalent in much of the water systems research arising from the physical sciences. A focus on emergent characteristic management challenges encourages us to go beyond searching for evidence of feedbacks and instead ask questions such as: What types of innovations have successfully been used to address these challenges? What structural components of the system affect its resilience to hydrological events and through what mechanisms? Are there differences between successful and unsuccessful strategies to solve one of the characteristic management challenges? If so, how are these differences affected by institutional structure and ecological and economic contexts? To answer these questions, social processes must now take center stage in the study and practice of water management. We also argue that water systems are an important class of coupled systems with relevance for sustainability science because they are particularly amenable to the kinds of systematic comparisons that allow knowledge to accumulate. Indeed, the characteristic management challenges we identify are few in number and recur over most of human history and in most geographical locations. This recurrence should allow us to accumulate knowledge to answer the above questions by studying the long historical record of institutional innovations to manage water systems

Exploring adolescents’ perceptions of dairy farming careers in Ireland: views of students studying agricultural science in secondary school

peer-reviewedA global challenge for dairy farmers is the attraction and retention of people to careers in primary agriculture. This study aimed to explore the perceptions of Irish secondary-level students studying agricultural science towards careers in dairy farming. Quantitative data were collected via a national survey (n = 976) prior to collection of qualitative data via two focus groups. Descriptive statistics including frequencies, percentages and means were used to analyse the quantitative data. Data analysis of the survey results identified general themes, which contributed to a deductive assessment of the overarching hypothesis, supplemented by inductive reasoning based on the analysis of the data from the focus groups. From the survey, adolescents perceived dairy farming as a physically demanding job with a poor work–life balance without any extra financial reward compared to other careers. In the focus groups, participants expressed concerns about environmental sustainability and economic viability. They also identified the ageing farming population as making it a less attractive career for young people. The paper supports arguments for greater integration of actual labour market opportunities into the secondary school curriculum to raise aspirations for 21st century careers in dairy farming, among other careers. There is an opportunity within the agricultural science curriculum to encourage students to explore the wide spectrum of emerging careers in food systems including dairy farming through classroom discussion, ideally with a variety of role models employed in the agricultural sector

The impact of work organisation on the work life of people on pasture-based dairy farms

The seasonal workload combined with increased dairy herd sizes and a declining workforce have created social sustainability challenges for pasture-based dairy farms. Effective work organisation can build productive capacity that may have a positive impact on this scenario. Our objective was to develop a framework to characterise and examine the effect of work organisation on the working situations of the people involved in a sample of 55 pasture-based dairy farms in Ireland. We conceptualised that effective work organisation on a dairy farm could be considered as a system that is efficient from a labour input perspective, resulting in a profitable farming system with outcomes of good operator well-being, health and safety, and quality of life. A literature review established efficiency & productivity, flexibility and standardisation as our three characteristics of work organisation. Using data from an existing labour time-use study completed from the 1st February to 30th June 2019, we aimed to test the veracity of these work organisation characteristics in the Irish pasture-based dairy system. Two proxy indicators were selected to represent each of the three work organisation characteristics, and each of the 55 farms were categorised into quartiles based on their ranking for these six indicators (1 = most effective quartile to 4 = least effective quartile). The most and least effective quartiles of farms for work organisation showed similar levels of farm labour input and labour efficiency. Farmers in the most effective work organisation quartile were working 51.2 h/week from February to June compared with 70.0 h/week for farmers in the least effective quartile, which was attributed to later start times, earlier finish times, and more time at non-farm activity. Farms achieving effective work organisation had a labour-efficient system with relatively low farmer working hours. Extension of the work organisation concept to other farms could improve their labour situation and aid in alleviating some of the key quality of life challenges faced by dairy farmers

Developing ‘Smart’ Dairy Farming Responsive to Farmers and Consumer-Citizens: A Review

Innovation has resulted in more dairy products being produced with less inputs than ever before. It has also affected how animals are raised, the structure of the sector and the nature of products produced. Not all impacts have been positive. As disruptive technologies—such as precision farming and robotics—herald significant change, it is timely to reflect on the perspectives of different actors on innovations within the sector. Drawing on a review of academic literature, this paper considers farmers’ and consumer-citizens’ perspectives; as expected, their diverse knowledge, interests and values surface a range of perspectives. To provide focus to the study, it examines technologies across three stages of the dairy production cycle: breeding, feeding and milking. It finds that consumer-citizen and farmer perspectives have been examined by researchers in several countries, using a variety of methods, across a range of technologies. It finds both areas of agreement and tension within and between consumer-citizen and producer cohorts. While differences in knowledge account for some variation, differences in values are also significant. The extent to which efforts can and should be put into addressing differences is raised as a point for reflection