Nutritive value of forage legumes used for grazing and silage

peer-reviewedLegume forages have an important position in ruminant production in Western Europe and with further development can play an even larger role. Red clover for silage and white clover in grazed swards lead to enhanced growth rate and milk yield in comparison with pure grasses. Much of the production benefit of these legumes relates to enhanced intake since digestibilities are not markedly different to grasses. The higher intake of legume silages reflects differences in the cell structure of legume plants which combined with high fermentation rates means that they break down into small particles in the rumen, and leave the rumen more rapidly than perennial ryegrass. Ease of ingestion leads to high rates of intake, which explains higher intakes for grazed legumes. A further benefit of legumes is the reduced rate of decline in digestibility with advancing maturity. Whilst legumes have limited effects on gross milk composition or carcass characteristics, there are marked increases in levels of beneficial n−3 PUFA. Legumes have often led to a reduction in methane production from the rumen and again, this relates to both physical and chemical differences between forage species. The high rates of release of soluble protein and of breakdown to small particles from clovers and lucerne is associated with susceptibility to bloat, which is a limitation to further exploitation in grazing systems. The high concentration of rapidly degraded protein in legumes also leads to inefficient utilisation of dietary N and increased urinary N output. Research with tanniniferous forages, such as birdsfoot trefoil and sulla, demonstrates the potential for future legumes with reduced environmental and health effects, though these particular forage legumes are not well adapted to temperate regions of Western Europe that are the focus of this review

Effect of Farm Grass Cover at Turnout on the Grazing Management of Spring Calving Dairy Cows

Early spring grazing is an objective for most Irish dairy farmers. If more grass is included in the diet of the cow in early lactation, the profitability of the farm system can be increased. Post turnout, dairy cow feeding management varies with the amount of farm grass cover (FC) available. Experiments on the consequences of different FC at turnout require large resources and all scenarios cannot be accounted for. Consequently, a decision support system, Pâtur’IN (Delaby et al., this volume), was used to describe the effects of various FC at turnout on grazing management in spring

Grass Growth Profiles in Brittany

For farmers, knowing the local grass growth profile and the possible variations between years is very helpful in managing grazing. Indeed, the comparison with herd needs and anticipated farm cover change allows decisions to be made that will maintain the cover at the desired level. This paper proposes a ten-days grass growth profile corresponding to Brittany’s different conditions of soil, climate and pasture management

Effect of Strategy of Forage Supplementation and of Turnout Date in a Medium Stocking Rate System on the Main Characteristics of Dairy Cows Grazing

Having a stocking rate of 2.9 cows per hectare of grassland (35 ares/cow) in Brittany offers many options for turnout date and forage supplementation strategies. For a farmer, knowing the consequences of the different options during the course of the grazing season makes grazing management decisions easier. As experiments on grazing management require considerable resources and are hardly generalisable, various spring scenarios have been tested using a dynamic decision support system, Pâtur’IN (Delaby et al., this volume)

An individual reproduction model sensitive to milk yield and body condition in Holstein dairy cows

To simulate the consequences of management in dairy herds, the use of individual-based herd models is very useful and has become common. Reproduction is a key driver of milk production and herd dynamics, whose influence has been magnified by the decrease in reproductive performance over the last decades. Moreover, feeding management influences milk yield (MY) and body reserves, which in turn influence reproductive performance. Therefore, our objective was to build an up-to-date animal reproduction model sensitive to both MY and body condition score (BCS). A dynamic and stochastic individual reproduction model was built mainly from data of a single recent long-term experiment. This model covers the whole reproductive process and is composed of a succession of discrete stochastic events, mainly calving, ovulations, conception and embryonic loss. Each reproductive step is sensitive to MY or BCS levels or changes. The model takes into account recent evolutions of reproductive performance, particularly concerning calving-to-first ovulation interval, cyclicity (normal cycle length, prevalence of prolonged luteal phase), oestrus expression and pregnancy (conception, early and late embryonic loss). A sensitivity analysis of the model to MY and BCS at calving was performed. The simulated performance was compared with observed data from the database used to build the model and from the bibliography to validate the model. Despite comprising a whole series of reproductive steps, the model made it possible to simulate realistic global reproduction outputs. It was able to well simulate the overall reproductive performance observed in farms in terms of both success rate (recalving rate) and reproduction delays (calving interval). This model has the purpose to be integrated in herd simulation models to usefully test the impact of management strategies on herd reproductive performance, and thus on calving patterns and culling rate

The Effects of a High Grass Input Feeding System Compared to High Concentrate Input Feeding System Offered to Spring Calving Dairy Cows in Early Lactation

Grazed grass is the cheapest feed available on Irish dairy farms. The inclusion of grass in the diet of the spring-calving dairy cow in early lactation is recommended. Previous studies focused on introducing grazed herbage into the cows diet in early spring in conjunction with grass silage and concentrate, and compared this to cows fed indoors. The objective of this study was to compare the milk production and feed budget of two contrasting early lactation feeding regimes. One regime was based on a high herbage inclusion with a low concentrate level (HG), while the other was based on a high concentrate inclusion with grass silage (HC)

The Effect of Early and Delayed Spring Grazing on the Milk Production, Grazing Management and Grass Intake of Dairy Cows

Earlier access to pasture can increase the overall proportion of grazed grass in the diet of the spring calving dairy cow. Further benefits can also be achieved from early turnout, including improved animal production, increased sward utilisation and enhanced sward quality (O’Donovan et al., 2004). The objective of this study was to compare the effect of initial spring grazing date and stocking rate on the performance of spring calving dairy cows