Temperate Pasture Research Articles

Current situation and future prospects for beef production in Europe - A review.

The European Union (EU) is the world’s third largest producer of beef. This contributes to the economy, rural development, social life, culture and gastronomy of Europe. The diversity of breeds, animal types (cows, bulls, steers, heifers) and farming systems (intensive, extensive on permanent or temporary pastures, mixed, breeders, feeders, etc) is a strength, and a weakness as the industry is often fragmented and poorly connected. There are also societal concerns regarding animal welfare and environmental issues, despite some positive environmental impacts of farming systems. The EU is amongst the most efficient for beef production as demonstrated by a relative low production of greenhouse gases. Due to regional differences in terms of climate, pasture availability, livestock practices and farms characteristics, productivity and incomes of beef producers vary widely across regions, being among the lowest of the agricultural systems. The beef industry is facing unprecedented challenges related to animal welfare, environmental impact, origin, authenticity, nutritional benefits and eating quality of beef. These may affect the whole industry, especially its farmers. It is therefore essential to bring the beef industry together to spread best practice and better exploit research to maintain and develop an economically viable and sustainable beef industry. Meeting consumers’ expectations may be achieved by a better prediction of beef palatability using a modelling approach, such as in Australia. There is a need for accurate information and dissemination on the benefits and issues of beef for human health and for environmental impact. A better objective description of goods and services derived from livestock farming is also required. Putting into practice “agroecology” and organic farming principles are other potential avenues for the future. Different future scenarios can be written depending on the major driving forces, notably meat consumption, climate change, environmental policies and future organization of the supply chain.

The effect of temperate or tropical pasture grazing state and grain-based concentrate allocation on dairy cattle production and behavior

Grain-based concentrate (GBC) supplement is of high cost to dairy farmers as a feed source as opposed to grazed pasture. Milk production response to GBC is affected by the composition and nutritive value of the remainder of the diet, animal factors, and interactions between forage type and level of GBC. In grazing systems, dairy cattle encounter contrasting pasture states, primarily because the social structure of the herd affects the timing of when each animal accesses a paddock after milking as a result of a relatively consistent cow milking order. However, the effect of feed management, namely pasture state and GBC allocation, on dairy cattle production and behavior is unknown. We examined the effect of varying GBC allocation for dairy cattle grazing differing states of kikuyu grass (Pennisetum clandestinum, a tropical pasture species; experiment 1) and annual ryegrass (Lolium multiflorum L., a temperate pasture species; experiment 2) on dry matter intake, milk production and composition, and grazing behavior. For each experiment, 90 lactating dairy cattle were randomly allocated to 2 consistent (fresh-fresh and depleted-depleted) and 2 inconsistent (fresh-depleted and depleted-fresh pasture state treatments (defined as sequences of pasture state allocation for the morning and afternoon grazing events) and 3 GBC treatments [2.7, 5.4, and 8.1 kg of dry matter (DM)/cow per day], giving 12 treatment combinations for each experiment. The duration of each experiment was 14 d, with the first 7 d used as adaptation to treatment. In each experiment, 3 cattle were selected from each of the 12 pasture type × GBC treatment groups within the experimental herd to determine herbage intake and total DM digestibility using the n-alkanes method (n = 36). There was no interaction between kikuyu grass or ryegrass pasture state and GBC level for intake, digestibility, or milk yield or components. Dairy cattle offered fresh-fresh and depleted-fresh ryegrass produced 9% more milk yield, in line with greater pasture intakes, compared with fresh-depleted and depleted-depleted pasture states. Dairy cattle offered fresh-fresh kikuyu grass had 8% more milk yield and 14% more milk protein yield than other pastures states, but there was no effect of pasture state on milk composition. Milk yield increased with GBC level for both pasture species (∼0.7-0.8 kg of milk/kg of DM GBC) as GBC level increased from 2.5 to 5.4 kg of DM/cow per day. There was a poor response (0.3 kg of milk/kg of DM GBC), and no response, when GBC levels increased from 5.4 to 8.1 kg of DM/cow per day for kikuyu grass and ryegrass, respectively, in line with pasture DMD. Time spent grazing, lying, and ruminating were not associated with kikuyu grass pasture state, GBC, or their interaction. Despite this, there was a linear increase in grazing time in the afternoon coinciding with a linear decrease in lying and rumination time for both kikuyu grass and ryegrass pasture. Together these findings reveal the effect of pasture state and GBC allocation on dairy cattle production and behavior. Tailoring GBC allocation to the state of pasture accessed by cattle appears unwarranted, but there is an opportunity to alter the timing of pasture access to increase herd-level milk production efficiency.

Milk production and grazing behaviour responses of Alpine dairy goats to daily access time to pasture or to daily pasture allowance on temperate pastures in spring

In a context of price volatility and low feed self-sufficiency of goat farms in Western Europe, grazing may play an important role. Knowledge about the impact of grazing management – particularly daily access time to pasture or pasture allowance – on dairy goats’ performance is scarce. Two 3-week trials were carried out in spring with 36 Alpine goats in mid-lactation. In Trial 1, 3 access times to pasture during daytime (AT: 4, 6 or 8 h/day, from 08:00 to 12:00, from 10:00 to 16:00 and from 08:00 to 16:00, respectively) were compared. In each treatment, goats individually received 370 g DM of dehydrated forage (lucerne and maize) after the evening milking, 278 g DM of concentrate twice daily, at each milking, and a daily pasture allowance of 2.0 kg DM/goat, measured at 4 cm above ground level. In Trial 2, 3 daily pasture allowances (PA: 1.6, 2.3 or 3.0 kg DM/goat, measured at 4 cm above ground level) were compared. Goats individually received 278 g DM of concentrate twice daily, at each milking, and access time to pasture was of 13 h/d (from 07:30 to 16:00 and from 17:00 to 21:30). Milk production was similar between medium and high levels of AT or PA, and was lower for the lowest level of AT or PA (−300 g/d at the lowest AT and −500 g/d at the lowest PA). Milk fat and protein concentrations only slightly varied between the different levels of AT or PA. In both trials, goats maintained an intense grazing activity. Grazing time (from 240 to 540 min/d) and proportion of time spent grazing (from 66 to 99%) were mainly affected by AT, and only marginally by PA.

Recovery from short-term complete submergence in temperate pasture grasses

The ability to recover from the impact of short-term submergence was assessed on four widely used grasses in pastures: Dactylis glomerata L., Bromus catharticus Vahl., Schedonorus arundinaceus Schreb. (syn. Festuca arundinacea) and Phalaris aquatica L. Six-week-old plants were subjected to a 5-day complete submergence in clear water, followed by a 15-day recovery period. Dry mass after submergence, shoot and root growth, number of tillers per plant, leaf stomatal conductance and leaf greenness during recovery were assessed. Dactylis glomerata and B. catharticus were sensitive to submergence, showing very low relative growth rate (RGR) of shoots and roots during recovery (37–67% lower than controls) along with early leaf senescence and persistent partial stomatal closure. Schedonorus arundinaceus exhibited an intermediate tolerance, sustaining high RGR of shoots (similar to controls) and fully adjusting its leaf functionality during recovery despite being affected during submergence (40% decrease in dry mass and 37% in tiller number). Phalaris aquatica performed outstandingly, with dry mass unaffected by submergence, and unaltered stomatal conductance, leaf greenness, tillering and shoot growth during recovery. Therefore, in areas where flooding can often cause plant submergence, P. aquatica is recommended whereas the other species are not, because they may be outcompeted by flood-tolerant species.

Intrinsic capacity for nutrient foraging predicts critical external phosphorus requirement of 12 pasture legumes

The mainstream pasture legume species such as Trifolium subterraneum, T. repens and annual Medicago spp. used in the temperate pasture systems of southern Australia have high critical external requirements for phosphorus (P) (i.e. P required to achieve 90% of maximum yield). This work aimed to identify alternative pasture legume species that could be used in systems with lower P input. Shoot and root biomass of 12 species of pasture legume was measured in response to seven rates of P applied to the top 48 mm of soil in a pot experiment. Most species had maximum yields similar to T. subterraneum, but some required only one-third of the applied P to achieve this. The critical external P requirement of the species, ranked from lowest to highest, was as follows: Ornithopus compressus = O. sativus < Biserrula pelecinus < T. michelianum = T. vesiculosum = T. glanduliferum < T. hirtum = Medicago truncatula = T. purpureum = T. incarnatum < T. spumosum = T. subterraneum. An ability to maximise soil exploration through a combination of high root-length density, high specific root length and long root hairs (i.e. a large specific root-hair-cylinder volume) was associated with a low critical external P requirement. The results indicate that Ornithopus spp. could be used to achieve productive, low P-input pasture systems.

Forage Options for Dairy Farms with Reduced Water Availability in the Southern Murray Darling Basin of Australia

The dairy industry in the southern Murray Darling Basin region of Australia is a major consumer of irrigation water because rainfall is low relative to evapotranspiration and the industrys relies heavily on irrigated temperate pastures and fodder crops. Water reforms, and potential climate change scenarios for this region suggest that there will be an overall decline in rainfall and water available for irrigation in the future. For the irrigated dairy industry to remain economically viable, there is a need for dairy farmers to improve the water productivity (WP) of their forage systems and to be able to respond to year-to-year, and within year, variation in water availability. Researchers and dairy farmers are evaluating strategies to increase WP. These include: (i) selecting better-adapted species for current and predicted climatic conditions; (ii) using species that can survive and still be productive under reduced irrigation and then recover when full irrigation is restored; (iii) modifying irrigation strategies to reduce water use whilst maintaining WP; and (iv) grazing management strategies that facilitate the survival during, and recovery after, periods of moisture stress. This review will examine these strategies and discusses their potential to optimise forage production from irrigation water inputs so that the dairy industry in the southern Murray Darling Basin remains viable in the future.

Linking management practices with range health in northern temperate pastures

Little information exists on the management and range health (RH) of northern temperate pastures, where health is defined as the ability to sustain ecosystem function. We surveyed 102 pastures for RH and their associated managers during 2012–2013 across central Alberta, Canada. Pastures were generally diverse mixes of introduced grasses and contained few legumes, despite most (55%) being seeded to legumes. The majority of pastures were healthy (mean RH score = 78.8% ± 1.3%), with 2.9% having scores <50%. Criteria reducing scores were noxious weeds, bare soil, and evidence of erosion. Most pastures had a reported history of cultivation (75.5%), with those previously cultivated and seeded to introduced forage having greater stocking rates [6.18 ± 0.91 animal-unit-months (AUM) ha−1] compared with those lacking cultivation (2.14 ± 2.91 AUM ha−1). Farms with horses or mixed livestock tended to practice year-round continuous grazing and supplemental hay feeding. Stocking rates on continuous and rotationally grazed pastures were similar regardless of grazing season, with the highest stocking on pastures used year-round (19.54 ± 2.03 AUM ha−1) or throughout the dormant season (20.29 ± 3.10 AUM ha−1). Use of management inputs was variable, with manuring and harrowing common and fertilizing, over-seeding, and aerating infrequent. Herbicide use was reported on 15.7% of pastures, despite 83.3% containing noxious weeds. Use of prescribed fire was rare, although 36.3% of pastures had evidence of fire. Industrial disturbances were reported on 48.3% of pastures. Overall, these results indicate that these pastures experience complex management and the limited decline in RH is due to high stocking under year-long grazing.

Rotational and continuous grazing does not affect the total net ecosystem exchange of a pasture grazed by cattle but modifies CO2 exchange dynamics

Grassland carbon budgets are known to be greatly dependent on management. In particular, grazing is known to directly affect CO2 exchange through consumption by plants, cattle respiration, natural fertilisation through excreta, and soil compaction. This study investigates the impact of two grazing methods on the net ecosystem exchange (NEE) dynamics and carbon balance, by measuring CO2 fluxes using eddy covariance in two adjacent pastures located in southern Belgium during a complete grazing season. Rotational (RG) grazing consists of an alternation of rest periods and short high stock density grazing periods. Continuous grazing (CG) consists of uninterrupted grazing with variable stocking rates. To our knowledge, this is the first study to assess the impact of these grazing methods on total net ecosystem exchange and CO2 exchange dynamics using eddy covariance. The results showed that NEE dynamics were greatly impacted by the grazing method. Following grazing events on the RG parcel, net CO2 uptake on the RG parcel was reduced compared to the CG parcel. During the following rest periods, this phenomenon progressively shifted towards a higher assimilation for the RG treatment. This behaviour was attributed to sharp biomass changes in the RG treatment and therefore sharp changes in plant photosynthetic capacity. We found that differences in gross primary productivity at high radiation were strongly correlated to differences in standing biomass. In terms of carbon budgets, no significant difference was observed between the two treatments, neither in cumulative NEE, or in terms of estimated biomass production. The results of our study suggest that we should not expect major benefits in terms of CO2 uptake from rotational grazing management when compared to continuous grazing management in intensively managed temperate pastures.

Performance and methane emissions by beef heifer grazing in temperate pastures and in integrated crop-livestock systems: The effect of shade and nitrogen fertilization

Methane (CH4) emissions from enteric fermentation by cattle are the main source of greenhouse gases in livestock systems, but scarce information is available on the effect of production scenarios on CH4 emissions. The objective of this study was to assess animal performance and CH4 emissions by beef heifers grazing in a mixed Lolium multiflorum×Avena strigosa pasture in two different types of integrated systems, crop-livestock only (CL) or crop-livestock-tree (CLT), and with two nitrogen (N) supply levels (90 and 180kgNha−1, N90 and N180, respectively). The study was performed during the winter season (i.e., stocking season) over three years (2012–2014). Pasture shading by 6- to 8-year-old trees in the CLT system led to a reduction in the total annual herbage accumulation of approximately 2.6Mg dry matterha−1 (−51%) and a reduction in winter carrying capacity of 0.5 stock units ha−1 in comparison to the CL system. Average daily gain (ADG) was reduced by 32% in CLT compared to CL. Average CH4 emissions were 163±9.12g CH4 day−1 in heifers with an initial average live weight (LW) of approximately 250kg. Emissions of CH4 per kg of LW did not differ between treatments (P>0.05) with a mean of 0.58±0.030gkg−1. However, there were significant differences between treatments and among years when CH4 was expressed in gkgADG−1 and kg ha−1day−1. Per unit area, CH4 production ranged between 0.51±0.05 (CLT N180) and 0.86±0.12kgha−1day−1 (CL N180). Possible strategies to reduce losses in animal production in the CLT systems are discussed, as well as the potential of C sequestration by woody biomass of eucalyptus trees to mitigate CH4 emissions.

Biochar carbon dynamics in physically separated fractions and microbial use efficiency in contrasting soils under temperate pastures

There is overwhelming evidence for the long-term persistence of biochar in soil. However, the partitioning of biochar into light and heavy carbon (C) fractions and microbial biomass C (MBC), and the dynamics of C use efficiency (CUEE: net incorporation of biochar into MBC per unit of biochar-C consumed, including microbial death and recycling of biochar-derived microbial metabolites) in planted soil systems are poorly understood. A 13C-labelled wood biochar (δ13C: −36.7‰) was incorporated into topsoil (0–10 cm) in an Arenosol, Cambisol and Ferralsol under C3 dominated temperate pastures (δ13C: −25 to −27‰). The partitioning of biochar-C into the various soil C pools and CUEE were measured at 4, 8 and 12 months. The results showed that 8.6–28.2% of the biochar-C in the top soils was distributed to the heavy fraction (HF) within 4 months, which increased to 11.0–33.3% at 8 and 12 months. Biochar-C recovery in the HF was the highest in the Ferralsol (cf. Arenosol and Cambisol), possibly due to greater interaction of biochar and biochar-derived microbial metabolites with soil minerals. Biochar significantly increased MBC across the three soils. Biochar-derived MBC ranged from 22 to 93 mg C kg−1 soil over time (Arenosol < Cambisol < Ferralsol), representing 11–20% of the total MBC pool. Biochar CUEE was 0.20–0.27 at 4 months, which decreased over time, possibly due to lowering of biochar-C availability to microbes. Further, although biochar-derived MBC was higher, biochar CUEE was lower in the Ferralsol (cf. Arenosol and Cambisol), likely supported by higher microbial respiration and turnover, and lower recycling of microbial metabolites via greater organo-mineral interaction. Here, the study advanced our understanding of key C cycling processes, such as CUEE and the temporal fate of biochar-derived C in an organo-mineral fraction with relevance for biochar sequestration in contrasting soils under planted field conditions.

Reference transcriptome assembly and annotation for perennial ryegrass.

RNA-Seq methodology has been used to generate a comprehensive transcriptome sequence resource for perennial ryegrass, an important temperate pasture grass species. A total of 931 547 255 reads were obtained from libraries corresponding to 19 distinct tissue samples, including both vegetative and reproductive stages of development. Assembly of data generated a final filtered reference set of 48 713 contigs and scaffolds. The transcriptome resource will support whole genome sequence assembly, comparative genomics, implementation of genotyping-by-sequencing (GBS) methods based on transcript sampling, and identification of candidate genes for multiple biological functions.

608 Replacing corn grain by crude glycerol in diets of grazing dairy cows: Feed intake, pasture degradability, and milk production

Eighteen Holstein cows (6 ruminally cannulated) were used in the first 60 days of lactation to evaluate the effect of the replacement of corn grain (CG) by crude glycerol (CGly) on organic matter intake (OMI), pasture degradability and milk yield (MY). Cows were blocked [by parity (3.17±1.42), body condition score (3.0±0.3), expected caving date], and assigned randomly to two treatments (T). T1= partially mixed diet (PMR) containing sorghum silage (SS) plus concentrate (CG, wheat grain, soybean expeller, minerals and vitamins) and T2= PMR containing SS plus concentrate where CGly -76.5% glycerol, ALUR Uruguay- replacing the CG. Both groups received PMR in individual feeders and grazed during afternoon in a temperate pasture with herbage allowance-above the ground level- 60 kg DM.cow-1.day-1. Chemical composition of PMR (OM, CP, NDF, and EE in g/kgDM) respectively was for T1 [934, 117, 317, and 5] and [927, 106, 297 and 46] for T2. OMI and the ruminal degradation kinetics of DM of pasture were measured in situ in two periods. PMR intake (OMI-PMR) was measured individually as the difference between the amounts offered and refused. OMI-forage was determined with chromium oxide (Cr2O3) and indigestible acid detergent fiber as external and internal marker respectively. In situ data was fitted to nonlinear model D(t)=a+b(1-e-ct), where D= disappearance of DM , (a) soluble fraction, (b) degradable fraction, and (c) degradation rate. MY was Individual measured daily. Intake, degradability parameters, and MY were analyzed with a mixed model whit repeated measures. The model included fixed effects: T, period/week, interaction T*period and cow as a random effect. The statistical analyzes were performed with SAS (2010), data are expressed as lsmeans (s.e) and were considered to differ when P < 0.05. Treatment or interaction did not affect Total organic matter intake, OMI-PMR or OMI-f and was [23.6(1.4), 12.7(0.5) and 10.9 (1.0)] kgOM.d-1 for T1 and [20.8(1.3), 10.9(0.5) and 9.8 (0.9)] kg OM.d-1 for T2 respectively. The parameters “a”, “b” “c” of pasture were not affected by T, period or interactions and averaged 20(3.1) g/kgDM 602 (3.6) g/kgDM, 0.04(0.007) h-1. Milk yields was not affected by treatment (30.6(1.0) kg.día-1) or interaction T*week of lactation (WOL) but as expected it was affected for WOL. The absence of negative effects related to the use of CGly in substitution of CG in these conditions allows its use up to 10% DMI for dairy cows without altering the efficiency of the milk production process.

Effects of plowing on vertical distribution of radioactive Cs and soil physicochemical properties in temperate pastures

AbstractThis study investigated the effects of plowing on the vertical migration of radioactive Cs, air dose rate, and soil physicochemical properties in temperate pastures after radioactive pollution from the 2011 Fukushima Daiichi Nuclear Power Plant accident. The study area consisted of three plowed pastures (decontamination treatment) and one non‐plowed pasture at the Kawatabi Field Science Center of Tohoku University, 150 km north of the nuclear power plant. Air dose rate was measured at the top, middle, and bottom of the slope of each pasture. A profile pit (1 m × 3 m) was excavated at each location. Plants, litter and soil samples (from 0 cm to the parent material layer) were collected from all locations during the summer of 2014 to determine the radioactive Cs concentration. Particle size distribution and bulk density of the soil samples were also measured. Air dose rate was higher on the non‐plowed (0.090–0.097 μSv h−1) than that on the plowed (0.047–0.073 μSv h−1) pastures. Radioactive Cs concentration was high in the litter layer (207–475 Bq kg−1 dry matter [DM]) and the topsoil (0–2.5 cm depth; 412–1139 Bq kg−1 DM) in the non‐plowed pasture. In the plowed pastures, these variables did not differ within the 0–40 cm layer. In the non‐plowed pasture, there were high sand (37.0%) and low silt (61.4%) proportions at 10–20 cm and the topsoil had a high bulk density. In the plowed pastures, these variables were similar within the 0–20 cm layer. The bulk density (P &lt; 0.001) and organic matter content (P &lt; 0.05) had significant relationships with the concentration of radioactive Cs. These results indicate that plowing reduced air dose rate.

Changes in the short‐term intake rate of herbage by heifers grazing annual grasses throughout the growing season

AbstractAnnual temperate grasses go through abrupt changes in morphological composition during the growing season, which can affect ingestive behavior of grazing cattle. However, few studies have examined the effects of gradual structural changes in annual temperate pastures on the herbage intake rate during the growing season. We hypothesized that lenient grazing (removal of 40% of the initial pre‐grazing height) maintains short‐term intake rate (STIR) of grazing cattle over the entire growing season, even with decreased leaf/stem ratios. The studied pastures contained Avena strigosa, Lolium multiflorum and a mixture of the two species. Short‐term intake rate was measured using the double weighing technique, evaluating both bite rate and bite mass. The percentage of stem + pseudostem and leaf lamina lengths in the herbage mass were measured. Relationships between sward structure and animal ingestive behavior were also examined. As the pasture growing season progressed, the STIR of heifers grazing annual temperate grass swards was affected more by the time required to take a bite than by bite mass. Moreover, the sward structure also changed after each grazing cycle, reducing the pre‐grazing leaf/stem ratio. However, reductions in the pre‐grazing leaf lamina mass (up to 37% of the sward herbage mass) and/or in the leaf lamina length (up to 52% of the extended tiller height) did not affect the STIR of grazing heifers, since the animals maintained their bite mass and time per bite. In summary, with a grazing down target of 40% of the pre‐grazing height, reductions in STIR of heifers grazing annual temperate grasses occurred when the pre‐grazing leaf lamina percentage was &lt;37% of the sward herbage mass and/or &lt;52% of the extended tiller height. These results suggested that to avoid STIR reductions during the last grazing cycles, managements to stimulate tillering and delay stem + pseudostem elongation are necessary and should be investigated.

Plectosphaerella cucumerina as a bioherbicide for Cirsium arvense: proof of concept

Plectosphaerella cucumerina (Lindf.) W. Gams was evaluated as a bioherbicide for Cirsium arvense L. (Scop.) using a Canadian and a New Zealand isolate. Both isolates defoliated C. arvense when applied at 1013 conidia ha−1 in water volumes ranging from 250 to 6400 l ha−1 with a rapid decline in effect with declining conidial dose. Repeat application and the addition of the adjuvant Pulse® penetrant to the conidial suspension increased the disease severity in C. arvense. Maximum disease occurred at 20 °C with a 48 h post-application dew period. The experiments demonstrate that P. cucumerina can defoliate C. arvense under the environmental conditions of temperate pastures where the weed is problematic. The results also show that modifications to formulation and strategic application may reduce the 48 h dew period requirement and risk to non-target species respectively, supporting the conclusion that the fungus has potential as a bioherbicide for C. arvense.

Survival and development of chicken ascarid eggs in temperate pastures.

Eggs of chicken ascarids (Ascaridia galli and Heterakis spp.) are believed to be hardy and survive for long periods. However, this has not been evaluated quantitatively and our study therefore aimed to determine development and recovery of chicken ascarid eggs after burying in pasture soil. Unembryonated eggs were mixed with soil, placed in sealed nylon bags and buried at 7 cm depth in pasture plots April (spring, n = 72) and December 2014 (winter, n = 72). Eight randomly selected bags per season were used to estimate pre-burial egg recovery [0 week post-burial (wpb)]. Eight random bags were removed at 5, 12, 23, 38, 52, 71 wpb per season and additionally at 104 wpb for spring burial. The content of each bag was analysed for numbers and development stages of eggs. Eggs buried in spring were fully embryonated within 12 wpb. In contrast, eggs buried in winter were developing between 23 and 38 wpb, so that all viable eggs seemed to be fully developed by 38 wpb. About 90% eggs disappeared within 23 wpb (spring) and 38 wpb (winter). Small proportions (2-3%) of seemingly viable and infective eggs were still recovered up to 2 years after deposition. In conclusion, most eggs buried in temperate pasture soil seem to experience a heavy mortality within a few months after the deposition, especially during warm periods. However, a small proportion of eggs may survive and remain infective for at least 2 years.

Evaluating the economics of concentrate feeding decisions in grazing dairy cows

Purchased concentrates are a significant variable cost of a dairy business. Farm economic theory states that feeding supplements will enable a dairy farmer to improve profit as long as the marginal revenue received from the milk produced exceeds the marginal cost of the supplement. To do this, the quantities of milk, milk protein and milk fat produced from a unit of concentrate added to the diet are needed. Recent research has compiled results from short-term concentrate feeding experiments conducted in Victoria over a 30-year period. Using these data, relationships for the response of milk production to cereal grain supplements in dairy cows grazing temperate pastures have been developed and shown to be a better predictor than previous relationships. These response functions were used in the present study to investigate the economics of tactical (short-term; weekly, monthly or seasonally) and strategic (medium- to longer-term) supplementary feeding decisions in a pasture-based system, including, specifically, how much concentrate should be fed in a particular farm situation, given a certain feed cost and milk price. In the present paper, the relevant production economics method is explained and applied to determine the amount of supplement to feed that will maximise the margin of total extra milk income minus the total cost of supplement, thereby adding the most to farm profit. Currently, when dairy farmers make decisions about how much more supplement to feed their herd, they are making implicit judgements about the extra milk, and other potential benefits, that they expect to result as well as what the milk will be worth. More finely tuned decisions about feeding supplements based on comparing marginal cost and marginal revenue would add more to farm profit than decisions based on other common criteria, such as feeding supplement for maximum milk production. While some farmers may already be feeding supplements close to the point where marginal cost equals marginal revenue, the formal method of marginal analysis reported here makes explicit what is done implicitly at present and tests farmers’ intuitive decision-making. More detailed information about the responses to supplements and the costs and benefits of feeding supplements under particular circumstances at different times through the lactation has the potential to enable better, more profitable decisions to be made about feeding cows and managing the whole farm.

Temporal Segregation between Dung-Inhabiting Beetle and Fly Species.

The coexistence of ecologically similar species (i.e. species utilizing the same resource) is a major topic in ecology. Communities are assembled either through the biotic interactions of ecologically similar species, e.g. competition, or by the abiotic separation of species along gradients of environmental conditions. Here, we investigated the temporal segregation, succession and seasonality of dung-inhabiting Coleoptera and Diptera that utilize an identical resource in exactly the same way. The data were collected from two temperate pastures, one in the United Kingdom and the second in the Czech Republic. There was no evident temporal separation between ecologically similar coleopterous or dipterous taxa during succession. In contrast, these two orders were almost perfectly separated seasonally in both combined and site-specific datasets. Flies were most abundant in the summer, and beetles were more abundant in the spring and autumn. Ecologically similar beetles and flies also displayed seasonal separation in both combined and site-specific data. Analyses within site-specific data sets revealed such a separation at both the order and species level. Season is therefore the main temporal axis separating ecologically similar species of dung-inhabiting insects in temperate habitats, while succession aggregates species that may have similar environmental tolerances (to e.g. dung moisture). This separation between ecologically similar taxa of beetles and flies may be attributable to either competition-based niche separation or to temperature tolerance-based habitat filtering, since flies have peak activity in warmer months while beetles have peak activity in cooler months.

A Review of Perennial Ryegrass Endophytes and Their Potential Use in the Management of African Black Beetle in Perennial Grazing Systems in Australia.

The major insect pest of Australian cool temperate pastures is the root-feeding insect Heteronychus arator (African black beetle, ABB). Significant pasture damage can occur even at low ABB densities (11 individuals per square meter), and often re-sowing of the whole paddock is required. Mitigation of the effects of pasture pests, and in particular subterranean species such as the larval form of ABB, can be challenging. Early detection is limited by the ability to visualize above-ground symptoms, and chemical control of insects in soil is often ineffective. This review takes a look at the historical events that molded the pastoral landscape in Australia. The importation route, changes in land management and pasture composition by European settlers may have aided the establishment of ABB in Australia. Perennial ryegrass Lolium perenne is discussed as it is one of the most important perennial agricultural grasses and is widely-sown in moderate-to-high-rainfall temperate zones of the world. Endophytic fungi from the genus Epichloë form symbiotic relationships with cool season grasses such as Lolium perenne (perennial ryegrass). They have been studied extensively and are well documented for enhancing persistence in pasture via a suite of bioactive secondary metabolites produced by the fungal symbionts. Several well-characterized secondary metabolites are discussed. Some can have negative effects on cattle (e.g., ergovaline and lolitrems) while others have been shown to benefit the host plant through deterrence of insect pests from feeding and by insecticidal activity (e.g., peramine, lolines, ergopeptines). Various control methods for ABB are also discussed, with a focus on the potential role of asexual Epichloë endophytes.

Synthesis of system outcomes for a grazing-management experiment in temperate native pastures

Increasing the intensity of grazing management from continuous grazing or set-stocking to intensive rotational grazing has been proposed as a way of improving the profitability and environmental outcomes for native pasture-based grazing systems in the high-rainfall zone (HRZ) of southern Australia. The present paper synthesised the results and outcomes of eight papers covering different aspects of a grazing-system study investigating the intensity of grazing management at Panuara (33°27ʹS, 148°56ʹE), 25 km south-west of Orange, New South Wales. The systems analysis covered soils and soil water, pastures, animal production, profitability and business risk by using a combination of field experiments and biophysical modelling. The experimental approach, engagement with stakeholders and the potential impact of the research outcomes are discussed; as are the future directions for grazing system research. Increasing the intensity of grazing management from a 1- to a 20-paddock system resulted in a 21% higher pasture growth, 22% higher stocking rate and 20% higher lamb production per hectare. However, modelling demonstrated that seasonal variability had a greater impact on profitability than did the management system, and whole-farm profitability of the 20-paddock system was lower than that of the 1- and 4-paddock systems due to higher infrastructure costs. Pasture stability was associated with a high perennial grass content (&gt;70%), and a stocking rate of 4.2 ewes/ha for continuous grazing or 5.3 ewes/ha for intensive rotational grazing limited the potential for degradation events. Advantages were identified in fencing and managing production zones, with different production potential within a farm, to improve utilisation across the landscape and efficiency of fertiliser use. The farming-system approach successfully integrated field research with pre- and post-experimental modelling, and with strategic input from an advisory group containing farmers, researchers and advisors, to develop a full understanding of the impact, at a system level, of increasing the intensity of grazing management in the HRZ.