The effects of farm management practices on liver fluke prevalence and the current internal parasite control measures employed on Irish dairy farms

Fasciolosis caused by Fasciola hepatica is responsible for major production losses in cattle farms. The objectives of this study were to assess the effect of farm management practices on liver fluke prevalence on Irish dairy farms and to document the current control measures against parasitic diseases. In total, 369 dairy farms throughout Ireland were sampled from October to December 2013, each providing a single bulk tank milk (BTM) sample for liver fluke antibody-detection ELISA testing and completing a questionnaire on their farm management. The analysis of samples showed that cows on 78% (n = 288) of dairy farms had been exposed to liver fluke. There was a difference (P < 0.05) between farms where cows were positive or negative for liver fluke antibodies in (a) the total number of adult dairy cows in herds, (b) the number of adult dairy cows contributing to BTM samples, and (c) the size of the total area of grassland, with positive farms having larger numbers in each case. There was no difference (P > 0.05) between positive and negative farms in (a) the grazing of dry cows together with replacement cows, (b) whether or not grazed grassland was mowed for conservation, (c) the type of drinking water provision system, (d) spreading of cattle manure on grassland or (e) for grazing season length (GSL; mean = 262.5 days). Also, there were differences (P < 0.001) between drainage statuses for GSL with farms on good drainage having longer GSL than moderately drained farms. The GSL for dairy cows on farms with good drainage was 11 days longer than for those with moderate drainage (P < 0.001). The percentage of farmers that used an active ingredient during the non-lactating period against liver fluke, gastrointestinal nematodes, lungworm, and rumen fluke was 96%, 85%, 77% and 90%, respectively. Albendazole was the most frequently used active ingredient for treatment against gastrointestinal nematodes (57%), liver fluke (40%) and lungworm (47%), respectively. There was a difference (P < 0.05) in the use of triclabendazole and albendazole between positive and negative farms, with triclabendazole use being more common in positive farms. This study highlighted differences in dairy management practices between Irish farms with dairy herds exposed or not exposed to liver fluke and stressed the need of fine-scale mapping of the disease patterns even at farm level to increase the accuracy of risk models. Also, comprehensive advice and professional support services to farmers on appropriate farm management practices are very important for an effective anthelmintic control strategy.     

Interaction of Grazing Muzzle Use and Grass Species on Forage Intake of Horses

The impact of horse preference and grass morphology on grazing muzzle effectiveness has not been investigated. The objective of this study was to determine the effectiveness of grazing muzzle use at reducing forage intake when horses grazed grasses with different morphology and preferences. The study was conducted in 2012 and 2013. Four horses were grazed in 2012, and three horses were grazed in 2013. Four species of perennial cool-season grasses were grazed in 2012 including Kentucky bluegrass (Poa pratensis L.), meadow fescue (Schedonorus pratensis Huds.), perennial ryegrass (Lolium perenne L.), and reed canarygrass (Phalaris arundinacea L.). In 2013, only Kentucky bluegrass and reed canarygrass were grazed because of winter kill of other species. Horses were allowed to graze a small pasture seeded with an individual species for 4 hours each day in June and August of 2012 and August and September of 2013. Horses grazed the same grass species for two consecutive days, one day with a muzzle and one day without. Before and after each grazing, a strip was mechanically harvested to determine initial and residual herbage mass. The difference was used to estimate forage intake. The effectiveness of a grazing muzzle was not affected by forage species (P ≥ .05). Use of a grazing muzzle decreased the amount of forage consumed by an average of 30% compared with not using a grazing muzzle (P < .0001). Results will aid horse owners and professionals in estimating forage intake of muzzled horses on pasture.     

Dairy sheep production research at the University of Wisconsin-Madison,USA-a review

Commercial milking of sheep is a new agricultural industry in the United States starting approximately 30 yr ago. The industry is still small, but it is growing. The majority of the sheep milk is used in the production of specialty cheeses. The United States is the major importer of sheep milk cheeses with 50 to 60% of annual world exports coming to the United States during the past 20 yr. Therefore, there is considerable growth potential for the industry in the United States. The only dairy sheep research flock in North America is located at the Spooner Agricultural Research Station of the University of Wisconsin-Madison. The research program started in 1993 and has been multifaceted; dealing with several areas important to commercial dairy sheep farmers. The East Friesian and Lacaune dairy breeds were compared and introduced to the industry through the research program. Both dairy breeds produced significantly more milk than traditional meat-wool breeds found in the U.S., but the two breeds differed in their production traits. East Friesian-cross ewes produced more lambs and slightly more milk than Lacaune-cross ewes whereas Lacaune-cross ewes produced milk with a higher percentage of fat and protein than East Friesian-cross ewes. Lactation physiology studies have shown that ewes with active corpora lutea have increased milk yields, oxytocin release during milking is required to obtain normal fat percentages in the milk, large udder cisterns of dairy ewes can allow for increased milking intervals, and short daylengths during late pregnancy results in increased milk yield. In the nutrition area, legume-grass pastures and forages with a higher percentage of legume will result in increased milk production. Grazing ewes respond to additional supplementation with increased milk yield, but it is important to match the supplement to the quality of the grazing. Ewes on high quality legume-grass pastures that are high in rumen degradable protein respond with increased milk production to supplements high in energy and/or     

Barley–legumes rotations for semi-arid areas of Lebanon

In arid and semi-arid areas of West Asia and North Africa, including the northern Bekaa Valley of Lebanon, farmers have been increasingly practicing continuous barley cultivation. The objectives of the study were to (1) determine whether barley monoculture is unsustainable¹, (2) ascertain if barley and total dry matter yields can be increased and sustained by including a legume crop in the rotation, and (3) determine which barley–legume rotations are more productive. The trial was set up in a randomised complete block design with two replicates under rain-fed conditions in 1994–1995 at the Agricultural Research and Educational Center (33°56′ N, 36°5′ E, 995 m above sea level). Eight two-phase barley-based rotations were compared: barley in rotation with barley, lentil, common vetch, bitter vetch, common vetch for grazing, medics for grazing, common vetch for hay, and common vetch with barley for hay. Seed and straw were harvested from barley and legumes in the first four rotations. Relative to the trial mean, seed and straw yield under barley monoculture slumped in 1997–1998 and did not recover since then. Infestation of wild barley was a cause of this yield decline. Barley–legume rotations yielded 44–80% more barley grain and 27–53% more barley straw than the barley monoculture over the 6 years (1995–1996 to 2000–2001). Furthermore, in the legume phase, common and bitter vetch gave higher seed yield than barley monoculture. Thus, all barley–legume rotations, except barley–medics, yielded more total dry matter than barley monoculture on the basis of per rotation cycle. Among the barley–legume rotations, the barley-common vetch for seed rotation gave the highest and most stable dry matter yield. In conclusion, barley monoculture was unsustainable, but barley yields could be increased and sustained by including legumes in the rotation. Farmers in semi-arid areas of Lebanon should discontinue practicing barley monoculture and adopt a barley–legume, such as common vetch, rotation.     

Plant species richness and composition in managed grasslands: The relative importance of field management and environmental factors

Decline of grassland diversity throughout Europe within the last decades is threatening biological diversity and is a major conservation problem. There is an urgent need to determine the underlying factors that control vascular plant species richness and composition in managed grasslands. In this study, 117 grasslands were sampled using standardised methods. Explanatory variables were recorded for each grassland site, reflecting the local field management, site-specific environmental conditions and large-scale spatial trends. Using variation partitioning methods, we determined the pure and shared effects of these three sets of explanatory variables on the plant species richness and composition in grasslands. Most of the explained variation in plant species richness was related to the joint effect of local field management and environmental variables. However, the applied variation partitioning approach revealed that the pure effect of spatial variables contributed relatively little to explaining variation in both the plant species richness and species composition. The largest fractions of explained variation in plant species composition were accounted for by the pure effects of environmental and local field management variables. Moreover, the results revealed that the main mechanisms by which these sets of explanatory variables affect plant species vary according to the type of management regime under study. From our findings we could conclude that particularly a reduction of nitrogen fertilisation on meadows and grazing at a low stocking rate on pastures can help to conserve biodiversity.     

Do artificial waterholes influence the way herbivores use the landscape? Herbivore distribution patterns around rivers and artificial surface water sources in a large African savanna park

It has been argued that the wide-scale provision of artificial surface water in semi-arid savannas may result in homogenisation of foraging regimes, compromising biodiversity and ecosystem resilience. This is the first landscape-scale study investigating to what degree artificial waterholes and natural rivers influence the distribution of large herbivores, and hence foraging patterns, in the Kruger National Park, South Africa. This is explored by examining consistencies within and differences between distribution patterns of herbivore feeding groups on different geologies. Seven years of dry season aerial census data of thirteen large herbivores were analysed in a GIS. It was found that different herbivores exhibit different distribution patterns around rivers and waterholes. It was found that most grazer species were associated with artificial waterholes, whereas browsers and mixed feeders were indifferent to waterholes and were associated with the main rivers. This has important management implications for artificial water provision in the KNP and potentially for other semi-arid African savanna conservation areas. Man-made waterholes are therefore features in the landscape that can change the distribution of herbivores, even in a landscape where natural water is available, transforming patterns of landscape use. Furthermore, it was also found that the underlying geology interacts with water distribution in shaping herbivore distributions, with artificial waterholes and rivers acting as stronger nodes of herbivore activity on nutrient-rich basaltic soils than nutrient-poor granitic soils. The results from this paper may be useful for designing surface water policies and management plans for Kruger and other savanna reserves in Africa in order to maximise biodiversity conservation.     

Habitat use and conservation of bumblebees (Bombus spp.) under different grassland management regimes

Declines in the natural populations of several bumblebee species across Britain and Europe are an increasing cause for concern. In this study the habitat use of bumblebees was investigated on Salisbury Plain Training Area, the largest remaining area of unimproved chalk grassland in north-west Europe. Habitat characteristics influencing the overall abundance, species richness and foraging activity of bumblebees included the diversity and abundance of flowering plant species (particularly of favoured forage plants such as Trifolium pratense), vegetation structure and height. It is suggested that different Bombus species respond to these habitat characteristics depending on their specific foraging and nesting requirements, the case of Bombus humilis being especially relevant. The effects of several grassland management practices were considered in terms of their suitability for the conservation of bumblebee habitats. Cattle grazing was shown to be preferable to both sheep grazing and the absence of any management, although the timing and intensity of such grazing was important. Small-scale disturbances caused by vehicle activity were also of value in producing locally abundant forage resources in less intensively managed grasslands.     

Collembolan grazing affects the growth strategy of the cord-forming fungus Hypholoma fasciculare

Mycelia of cord-forming fungi show remarkable patterns of reallocation of biomass and nutrients indicating an important role of these, often extensive, organisms in the spatial translocation of energy and nutrients in forest soils. Despite the rich tradition of interaction studies between soil microarthropods and fungi, the spatial implications of these interactions, due to the potential growth responses of the fungi and to the translocation of energy and nutrients within the mycelial network, have been largely ignored. In this paper we analyse fungal growth responses in two-dimensional model systems composed of compressed soil, the cord-forming fungus Hypholoma fasciculare and three fungivorous Collembolan species. We hypothesised that (i) the highly co-ordinated nature of cord-forming fungi would lead to growth responses following collembolan grazing, and that, (ii) such changes are dependent on grazing intensity, and (iii) changes are dependent on the species grazing. Mycelial extent and hyphal cover decreased with increasing grazing density; at highest grazing density also the fractal dimension of the mycelial border decreased, indicating a less branched foraging front due to the regression of fine hyphae and the development of mycelial cords. Effects differed greatly between collembolan species although they exerted comparable grazing pressure (the smaller species were added in larger numbers according to their allometric size-metabolic rate relationships): while grazing by Folsomia candida resulted in less mycelial extension and hyphal cover, these variables were not affected when Proisotoma minuta and Hypogastrura cf. tullbergi grazed. The effects of a species mix suggested an additive effect of the component species. This shows that fungal mycelia may suffer from damage caused by few but large collembolans, affecting extension as well as coverage of the mycelium, but that fungi may compensate for the biomass loss caused by more but slightly smaller collembolans. In about 20% of the model systems H. fasciculare switched from a growth pattern with a broad contiguous foraging front and uniform growth in all directions to a pattern with fast growing sectors while other sectors stopped growth completely. The switch occurred in grazed systems exclusively; thus we interpret this observation as a fugitive response and as a strategy for quickly escaping from places where grazing pressure is experienced.     

Effects of grassland abandonment, restoration and management on butterflies and vascular plants

When semi-natural pastures are abandoned, specialized grassland species are lost as a consequence of succession. As a counter-measure, previously abandoned grasslands may be restored by clearing shrubs and trees and re-introducing grazing livestock. In order to examine the effects of this type of habitat restoration, we compared species richness of plants and of specialized plants thought to be dependent on continuous management and species richness and abundance of butterflies and red-listed butterflies in 12 sets of matched continuously managed, abandoned and restored grassland in southern Sweden. We found no differences in species richness or abundance between the three grassland types. There were, however, some negative effects of abandonment. The number of management-dependent plants decreased with increasing cover of trees and shrubs, and in restored sites species richness of all groups decreased with increasing cover of trees and shrubs before restoration. Also the present management significantly affected both butterflies and plants. Species richness of both groups increased with increasing vegetation height and differed between sites depending on the species of grazers, with negative effects of sheep compared to cattle or horses. Our study indicates that for grassland management to be efficient, the restoration actions should mainly be directed towards sites where the post-abandonment succession has not proceeded too far.