Effects of livestock breed and rearing experience on foraging behaviour of yearling beef cattle grazing unimproved grasslands

The relative importance of breed versus rearing experience on the grazing behaviour and diet selection of beef cattle when grazing unimproved grassland was examined over 4 years. Suckler‐reared calves of a traditional (T) breed (North Devon) or a commercial (C) breed (Simmental × Hereford Friesian) were cross‐fostered and then reared either extensively (E) on unimproved grassland or intensively (I) on agriculturally improved fertilized grassland. As yearlings, the four groups of calves (Traditional breed + Extensive rearing (TE); Traditional breed + Intensive rearing (TI); Commercial breed + Extensive rearing (CE) and Commercial breed + Intensive rearing (CI)) grazed unimproved grassland dominated by Molinia caerulea, for 2 months, and foraging behaviour was studied in a test phase. There was a breed effect on total (bites + chews; TJM) jaw movement rate (T, 78·2 vs. C, 76·5 min^?1; F prob. = 0·041) during grazing and on the proportion of bites taken from plant communities with sward height ≥6 cm (T, 0·83 vs. C, 0·76; F prob. = 0·018). Rearing experience affected TJM rate in the first year in July (E, 80·0 vs. I, 76·8 min^?1; F prob. = 0·015) and August (E, 78·5 vs. I, 75·5 min^?1; F prob. = 0·046). The intensively reared animals grew less well on average during the test phase than those that had previous experience of the unimproved grassland as calves with their mothers (E, 0·16 vs. I, 0·09 kg day^?1; F prob. = 0·033). Our findings indicate that the rearing experience of livestock appears to be as important as the breed when designing grazing managements for nature conservation areas.     

Effects of spreading species‐rich green hay on the botanical composition of an agriculturally improved hay meadow in northern England

The technique of enhancing species diversity by spreading species‐rich green hay following turf scarification was tested in a semi‐improved meadow site in Cumbria, UK. Botanical assessments were carried out in May 2008 (prior to treatment), May and October 2009, and May 2010. Both total species‐richness (number of species per m²) and the richness and aggregate cover of positive indicator species were enhanced by hay spreading, with an average of 21·8 species per m² compared with 17·0–18·7 species per m² for other treatments by May 2010. Significant increases in all three variables occurred by May 2009, with even greater increases between this assessment and May 2010. Hay spreading introduced seven new species, most of which subsequently increased over time, and enhanced the frequency of a further seven. All these species together accounted for only about 5% of vegetation cover in 2010, but the level of species‐richness achieved was equivalent to that of good quality semi‐improved grassland and also equivalent to that achieved in studies where the technique was developed. Results are discussed in detail in relation to the seeding phenology of species at the donor site, as are other factors affecting the technique's potential and possible means of enhancing it.     

A correction for the influence of changes in lamina weight per unit length in grasses on measurements of the weight of lamina removed by grazing

Changes in the weight per unit length along the first and second fully-expanded laminae of Lolium perenne, Agrostis stolonifera, Holcus lanatus and Poa trivialis were experienced in tillers harvested in April and June 1987 from a permanent pasture under contrasting nitrogen treatments. Schematic models representing the weight distribution along the laminae of the different species are presented. From these models, predictions of the weight of any given proportion of the lamina length have been calculated. The weight of segments of lamina have been estimated, using the appropriate lamina model for a species, and these estimates provided consistently greater precision than estimates of lamina weight when no correction for lamina shape was considered, the length of a segment of lamina simply being multiplied by the mean overall weight per unit length of the lamina.     

The impact of organic and inorganic fertilizers and lime on the species-richness and plant functional characteristics of hay meadow communities

Vegetation responses to fertilizers and lime applied in a seven-year study at paired unimproved and semi-improved mesotrophic hay meadows in Cumbria and Monmouthshire, UK, are described in terms of species-richness and several other plant community variables. Treatments were farmyard manure (FYM) applied at rates of between 6 and 24 tonne ha⁻¹ annually or every third year, inorganic fertilizers giving equivalent amounts of N, P and K, and lime applied either alone or with FYM applied annually or three-yearly. Annual FYM at 24 tonne ha⁻¹ reduced species-richness and the richness of positive indicator species at all sites and increased the proportional cover of nutrient-demanding species, whilst liming in conjunction with 12 tonne ha⁻¹ annual FYM application was equally detrimental at the unimproved site in Wales but not in Cumbria. Inorganic fertilizers were apparently no more detrimental to vegetation quality than equivalent FYM treatments, although medium-term nutrient supply from FYM may have been underestimated. Species-richness was maintained by FYM at ?12 tonne ha⁻¹ year⁻¹ in the semi-natural northern meadow, where such levels had been used in the past, but only by amounts equivalent to ?6 tonne ha⁻¹ year⁻¹ at the Welsh sites which had no recent history of fertilizer use. It is unclear to what extent such differences are attributable to innate differences in plant community type, rather than to site-specific differences in past management. The implications of our findings for defining sustainable fertilizer practices to maintain or enhance the nature conservation value of mesotrophic meadows are discussed.     

Spatial and structural uniformity of lowland agricultural grassland in England: a context for low biodiversity

The contention that agricultural grassland within the UK is spatially and structurally uniform across wide differences in livestock farming intensity is examined. Total nitrogen (N) input was used as a surrogate for management intensity. Farms with average annual N inputs of >200 kg ha^?1 were categorized as highly intensive, those with N inputs of 50–200 kg N ha^?1 as moderately intensive and those with inputs of <50 kg N ha^?1 were categorized as extensive. Four farms within each management category were selected in two discrete regions: one in south‐west England, typifying a landscape dominated by agricultural grassland, the other in south‐east England with a more mixed‐farming landscape. Specific N input and management data, and sward botanical composition and structure, were obtained on four fields per farm. The south‐west region had a higher proportion of farms with dairy cattle than in the south‐east England region. The average N input and stocking rates were higher within the intensive‐management category farms in south‐west England than in south‐east England. Old permanent grasslands contained variable amounts of sown species, such as Lolium perenne, and were dominated by a few (generally <5) non‐sown grass species. Grassland that received >75 kg N ha ^?1 year^?1 contained <7 plant species and <3 forb species m^?2. Grassland communities with >12 plant species and >5 forb species m^?2 were only found in study fields that received <50 kg N ha^?1 year^?1. Grasslands with >10 forb species m^?2 were found only in sites receiving <15 kg N ha^?1. Of importance at a landscape scale was ubiquity of species‐poor and similar grassland plant communities across the management intensity range within and between livestock farms. Grassland in the extensive management category was similar in structure in terms of sward height and/or sward density to more intensively managed grasslands. This study revealed, albeit in two lowland sample regions in the UK, the ubiquity of grass‐dominated, species‐poor and structurally uniform grasslands, irrespective of apparently broad differences in farming intensity. The consequences of this spatial uniformity on grassland biodiversity are likely to be profound.     

Minimizing environmental impacts of grassland weed management: can Cirsium arvense be controlled without herbicides?

Invasion by undesirable plants, such as Cirsium arvense, can constrain attempts to conserve and restore biodiversity in extensively managed temperate grasslands, but control with herbicides can cause environmental harm. We contrasted herbicides with more environmentally sustainable weed control strategies. Six‐year, large‐scale randomized block experiments were established to determine optimum combinations of grazing management and mechanical or herbicide treatments to control thistles within lowland and upland grazing systems. Factorial combinations of tight vs. lenient grazing in spring and autumn with additional treatments of winter grazing were compared. Thistle control methods were applied in sub‐treatments for the first 2 years: cutting twice yearly, herbicide wiping, and cutting followed by herbicide application. Thistle abundance decreased under lenient grazing in spring, autumn and winter at the lowland site, under lenient spring and winter grazing in the uplands and under cattle compared with sheep grazing. Herbicide wiping was the most effective control measure and cutting the least, but effects of all weed control sub‐treatments were lost rapidly, so lenient grazing was sufficient to give long‐term thistle control. Lenient grazing and herbicide wiping also caused small declines in non‐target forb diversity. Control of creeping thistle can therefore be achieved without herbicides because lenient grazing in spring and autumn can decrease thistle populations to sufficiently low levels. Severe infestations can be more rapidly controlled using herbicides, but are better avoided at botanically diverse sites. Ecologically‐based weed control strategies have great potential, but require well designed field experiments, which run for sufficiently long periods to allow community‐level impacts to develop.     

Hay production from lowland semi-natural grasslands: a review of implications for ruminant livestock systems

Data on total, seasonal and between-year variability in the productivity and nutritional quality of cut forages obtained from a range of lowland semi-natural grasslands are reviewed. Dry-matter production, as hay, from unfertilized species-rich semi-natural grasslands ranged from less than 20% to about 80% of the production that might be expected from agriculturally improved and intensively managed grasslands. Unfertilized species-rich grasslands had lower growth rates, reflecting low nutrient availability in spring and early summer. Low soil phosphorus availability appears to be a key factor allowing high species-richness to be maintained. The in vitro digestibilities of herbage cut for hay from semi-natural grasslands were 20%, or more, below values for conserved forages from intensively managed grassland. When losses incurred during the hay-making process were taken into account, then the nitrogen content of hays from many semi-natural grasslands appear to be sub-optimal for productive livestock. Metabolizable energy values of herbage cut for hay were 10–40% below values for intensively managed conserved grass. Phosphorus content of forages from most species-rich grasslands was either below the metabolic requirement of livestock or inadequate to sustain high individual animal performance. Potential problems associated with supplementation of the diet with phosphorus, and with high calcium-to-phosphorus ratios, are discussed. Although potassium content of most of the herbage cut for hay was adequate for productive ruminant livestock, exceptions arise with hay cut after July. The magnesium content of cut herbage from some semi-natural grasslands was below an adequate level for productive livestock. Most cut herbage appeared to contain adequate amounts of sodium. Inadequacy of the mineral content of hays from semi-natural grasslands for ruminant livestock will be exacerbated by nutrient losses incurred during the hay-making process and particularly so when hay- making is prolonged by wet weather. Few feeding studies using hays from semi-natural grasslands of high nature conservation interest have been conducted. Lack of such data makes it difficult to plan any integrated use of these hays in ruminant feed budgets for livestock systems.