DairyNZ

 
   DairyNZ
   

DairyNZ
   

DairyNZ is the centre of on-farm dairy research and development in New Zealand.
   

 DairyNZ includes teams of researchers with skills relevant to the Centre in dairy farm systems management, dairy cow feeding and growth, milk production performance, environmental science, on-farm practice change and technology uptake.

http://www.dairynz.co.nz
  
   

DairyNZ




 

  • Dairy committed to lowering environmental impact

    Commenting on today’s OECD Environmental Performance Review announcement, DairyNZ’s chief executive Dr Tim Mackle says the dairy sector is committed to lowering its environmental impact, while protecting the valuable contribution dairying makes to the economy.

    “Dairy farming is a major driver in the New Zealand economy improving everyone’s lifestyle in this country. This is both directly and indirectly, and in rural and urban communities,” he says.

    Read more

  • Feeding diets with fodder beet decreased methane emissions from dry and lactating dairy cows in grazing systems

    Jonker Arjan, Scobie David, Dynes Robyn, Edwards Grant, De Klein Cecile, Hague Helen, McAuliffe Russel, Taylor Anna, Knight Trevor, Waghorn Garry (2017) Feeding diets with fodder beet decreased methane emissions from dry and lactating dairy cows in grazing systems. Animal Production Science 57, 1445-1450.

    Abstract
    Fodder beet (Beta vulgaris L.) has a very high readily fermentable carbohydrate concentration, which could affect rumen fermentation and reduce enteric methane (CH4) emissions. The objective of the current study was to estimate CH4 emissions from dry dairy cows grazing either fodder beet supplemented with perennial ryegrass (Lolium perenne L.)-dominated pasture silage (6 kg DM/cow/day; FB+Sil) or forage kale (Brassica oleracea L.) supplemented with barley (Hordeum vulgareL.) straw (3 kg DM/cow/day; kale+Str; dry cows, Experiment 1), and from dairy cows in early lactation grazing perennial ryegrass-dominated pasture alone (pasture) or supplemented with fodder beet bulbs (3 kg DM/cow/day; past+FB; lactating cows; Experiment 2). Methane measurements were performed using GreenFeed units (C-Lock Inc., Rapid City, SD, USA) for 40 days in August–September 2015 (Experiment 1) and for 22 days in November–December 2015 (Experiment 2), from 45 and 31 Holstein–Friesian × Jersey dairy cows in Experiments 1 and 2, respectively. Dry cows grazing FB+Sil in Experiment 1 produced 18% less CH4 (g/day) and had 28% lower CH4 yield (g/kg DM intake; P < 0.001) than did cows grazing kale+Str. Lactating cows grazing past+FB in Experiment 2 produced 18% less CH4 and had 16% lower CH4 intensity (g/kg fat and protein-corrected milk production; P < 0.01) than did cows grazing pasture alone, while milk production and composition were similar for the two groups. In conclusion, feeding fodder beet at ~50% and 20% of the diet of dry and lactating dairy cows in pastoral systems can mitigate CH4 emissions.

    Read more (external link)

  • How can I estimate my on farm GHG emissions?

    In New Zealand, In New Zealand, farmers can get a farm-level estimate of their greenhouse gas emissions (methane and nitrous oxide, and in some cases also energy use) using commercially available calculators, such as OVERSEER.

    These calculators tend to rely on the use of default emissions from specified activities and only take into account a limited number of the factors that influence greenhouse gas emissions in practice. They are, however, useful for assessing how emissions change over time in response to management decisions such as fertiliser use and changes in animal numbers.

    What is OVERSEER?

     

  • Development of an improved representation of rumen digesta outflow in a mechanistic and dynamic model of a dairy cow, Molly

    Pablo Gregorini, Pierre Beukes, Garry Waghorn, David Pacheco, Mark Hanigan, Development of an improved representation of rumen digesta outflow in a mechanistic and dynamic model of a dairy cow, Molly, Ecological Modelling, Volume 313, 2015, Pages 293-306, ISSN 0304-3800, http://dx.doi.org/10.1016/j.ecolmodel.2015.06.042.

    Abstract

    Accurate predictions of outflow of digesta from the rumen are critical for improving modeling of feed intake, rumen function and fermentation patterns of ruminants. The main objective of this work was to develop an improved representation of rumen digesta outflow in the Molly model. The work is primarily an integration of existing knowledge of rumen digestion responsible for variations in digesta outflows in ruminants, and describes the structure and function of the new development, assessing the new model in terms of ruminal outflow and fermentation in response to different feeding scenarios. The present development includes three changes to the model: (1) a medium-size particle pool was added to the rumen which was assumed to ferment and pass from the rumen; (2) particulate passage was made a function of particle size, particle concentrations in the rumen, and liquid passage rate; and (3) fermentation rate was made a function of particle surface area in the medium and small particle pools. Although prediction accuracy of digestive functions was not substantially improved by the change in model structure, the model now reproduces observed patterns of variation in rumen function as affected by the food intake and dietary particle size compared with those reported in the literature, which was not previously the case. It also reproduces more realistic trends in rumen fermentation patterns, digestion and methane yields. The concepts embedded in the new development capture underlying biological mechanisms driving the variation in digesta outflows from the rumen that were not captured before.

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  • 1115 Rick Pridmore, Strategy and Investment Leader for Sustainability (DairyNZ)

    Rick provided the conference delegates with an overview of the New Zealand investment landscape for reducing agricultural greenhouse gases.

    He highlighted that New Zealand is putting in a great deal of effort into reducing agricultural greenhouse gas emissions and conducting top class science, which in many areas is nearing proof of concept.

    Rick also emphasised that there are a significant number of funders in this area covering government, industry, the universities and CRIs.

    At the research end, the plans and investment are fairly coordinated, mainly due to the actions of the NZAGRC and PGgRc, however at the applied end there is room for improvement. This is primarily due to the fact that there are many issues to be considered on-farm and greenhouse gas emissions are just one of the factors in the mix.

    New Zealand farm greenhouse gas emissions intensity has been decreasing at approximately 1% per year due to increased efficiency and the goal is to keep this rate going into the future, but on top of that, reduce emissions intensity by a further 1.5% per year by additional technological options. This 1.5% may be achieved by step changes between 2020 and 2050, rather than a gradual decline.

    Rick outlined the four key research aims of the NZAGRC-PGgRc methane programme:

    • Animal Selection
    • Low greenhouse gas Feeds
    • Vaccine
    • Inhibitors

    Breaking News: In the last four months, five lead inhibitor compounds have been shown to reduce methane emissions from animals by 30-90%, which is very exciting. Once proof of concept has been firmly established, commercial partners will be sought to take prototype vaccines and inhibitors through into the hands of the farming community. See more about this 

    Rick concluded by pointing out that 10 years ago, the task of reducing agriculture’s greenhouse gas emissions seemed enormous, and that we should all be proud that we are nearly there.

    Download presentation 

  • Carbon balance of an intensively grazed temperate dairy pasture over four years

    S. Rutledge, P.L. Mudge, D.I. Campbell, S.L. Woodward, J.P. Goodrich, A.M. Wall, M.U.F. Kirschbaum, L.A. Schipper, Carbon balance of an intensively grazed temperate dairy pasture over four years, Agriculture, Ecosystems & Environment, Volume 206, 1 August 2015, Pages 10-20, ISSN 0167-8809, https://doi.org/10.1016/j.agee.2015.03.011.

    Abstract
    We estimated the net ecosystem carbon (C) balance (NECB) of a temperate pasture in the North Island of New Zealand for four years (2008–2011). The pasture was intensively managed with addition of fertiliser and year-round rotational grazing by dairy cows. Climatic conditions and management practices had a large impact on CO2 exchange, with a severe drought in one year and cultivation in another both causing large short-term (∼3 months) net losses of CO2–C (100–200 g C m−2). However, CO2 was regained later in both of these years so that on annual timescales, the site was a CO2 sink or CO2 neutral. Management practices such as effluent application and harvesting silage also influenced non-CO2–C fluxes, and had a large impact on annual NECB. Despite these major environmental or management perturbations, both NEP and NECB were relatively constant on annual timescales. It is likely that this apparent resilience of the CO2 and C balance to perturbations was at least partly attributable to the relatively warm temperatures, also in winter, providing good growing conditions year-round (in the absence of major perturbations such as moisture stress). In several instances, the farmer’s decisions aimed at maintaining a constant milk yield between years also appeared to contribute to a relatively stable C balance.

    Averaged over the full four-year study period, the site was a net sink for both CO2 (NEP = 165 ± 51 g C m−2 y−1), and total C (NECB = 61 ± 53 g C m−2 y−1) after non-CO2–C fluxes were accounted for. Annual NEP and NECB values were similar to results collated from other managed temperate grasslands on mineral soils globally, for which average NEP and NECB were 188 ± 44 g C m−2 y−1 and 44 ± 33 g C m−2 y−1, respectively. In the global dataset, we noted a general trend for increased C sequestration with increasing NEP, suggesting that it may be possible to meet the dual goal of increased pasture production (thus milk, meat and fiber production) and increasing soil C storage in managed temperate grasslands. Identification of management practices that increase C storage while maintaining or enhancing pasture production requires more standardised reporting between NECB studies, and experiments involving side-by-side comparison of treatment and control plots.

    Read more (external website)

  • Decreasing methane emissions by feeding grazing ruminants: a fit with productive and financial realities?

    Pacheco, D., G. Waghorn, et al. (2014). "Decreasing methane emissions from ruminants grazing forages: a fit with productive and financial realities?" Animal Production Science 54(9): 1141-1154.

    Ruminants contribute to human food supply and also anthropogenic greenhouse gas (GHG) emissions. An understanding of production systems and information on animal populations has enabled global inventories of ruminant GHG emissions (methane and nitrous oxide), and dietary strategies are being developed to reduce GHG emissions from ruminants. Mitigation strategies need to consider the management/feeding systems used to ensure that these strategies will be readily accepted and adopted by farmers. Housed systems allow diets to be formulated in ways that may reduce GHG production, but the challenge is much greater for systems where animals graze outdoors for long periods. A methane mitigation option in the form of fresh forage would be desirable in livestock production systems with high reliance on grazing. A brief summary of New Zealand research, carried out on fresh grasses, legumes, herbs and crops, suggest that we have an incomplete understanding of the feed characteristics that define a ‘high’ or a ‘low’ methane feed. The variation in methane emissions measured between feeds, individual animals and experiment is large, even in controlled conditions, and the dynamic nature of sward-animal interactions will only exacerbate this variation, creating challenges beyond the identification of mitigants. Furthermore, implementation of knowledge gained from controlled studies requires validation under grazing systems to identify any trade-offs between methane reduction and animal productivity or emission of other pollutants. Therefore, investment and research should be targeted at mitigation options that can and will be adopted on-farm, and the characteristics of temperate grasslands farming suggest that these options may differ from those for intensive (high input/output) or extensive (low input/output) systems.

    https://doi.org/10.1071/AN14437

  • The effects of fresh forages and feed intake level on digesta kinetics and enteric methane emissions from sheep

    K.J. Hammond, D. Pacheco, J.L. Burke, J.P. Koolaard, S. Muetzel, G.C. Waghorn, The effects of fresh forages and feed intake level on digesta kinetics and enteric methane emissions from sheep, Animal Feed Science and Technology, Volume 193, 2014, Pages 32-43, ISSN 0377-8401, http://dx.doi.org/10.1016/j.anifeedsci.2014.04.005.

    Abstract

    Published data have shown that in ruminants, methane (CH4) yields (g/kg dry matter [DM] intake) decline as feed intakes increase and, although the reduction has been attributed to a shorter digesta mean retention time (MRT), there are few supporting data. This study was undertaken to determine the association between digesta kinetics and CH4 emissions measured from sheep in respiration chambers fed either fresh white clover (Trifolium repens; WC) or fresh perennial ryegrass (Lolium perenne; RG) (Experiment 1), or RG at several feed intakes (Experiment 2). Measurements included CH4, whole tract apparent DM digestibility (DDM), total tract and rumen MRT (TMRT and RMRT, respectively) of solid and liquid fractions, as well as passage rates. In Experiment 1, eight sheep each with a rumen fistula were fed hourly either WC or RG forages, repeated over two periods (four sheep/diet/period) at about 1.6 times maintenance requirements for metabolisable energy (MEm; 1.12kg DM/d). Diet did not affect apparent DDM (726g/kg), CH4 yield (22.3g/kg DM intake), or TMRT of solid fractions (29.4h). However, TMRT for the liquid fraction was shorter (P=0.037) for sheep fed RG (17.4h) compared with WC (23.0h), and rumen digesta analyses suggested a larger rumen liquid pool size when RG was fed (6.05L) compared with WC (3.96L) (P=0.041). Experiment 2 involved 30 sheep offered fresh RG twice daily at about 0.8, 1.2, 1.6, 2.0 and 2.5×MEm. The DDM did not differ greatly across RG intakes (625–648g/kg) but, as RG intake increased (0.49–1.34kg DM/d), there were corresponding reductions (P<0.001) in CH4 yield (27.0–23.9g/kg DM intake), liquid TMRT (31.4–14.2h), solid TMRT (46.4–24.8h), liquid RMRT (18.4–7.5h), and solid RMRT (28.4–15.8h). When CH4 yield was plotted against rumen liquid and solid passage rates, the extent of the relationship was best explained (R2) when RG was fed at different intakes in Experiment 2 (0.71 and 0.66 for liquid and solids, respectively). The 2.7-fold increase in feed intake halved RMRT, but intakes affected passage of the rumen liquid fraction to a greater extent than solids. It can be concluded that reductions in CH4 yield from fresh forages fed to sheep are associated with shorter TMRT and RMRT. Understanding the effects of diet, digestion, feed intake, and feeding frequency on methanogenesis requires more knowledge about rumen digesta kinetics, especially relationships between outflow rates of solid and liquid fractions.

    Read more (external website)

  • Estimating nitrous oxide emissions from a diary farm using a mechanistic, whole farm model and segregated emission factors for New Zealand

    Vogeler, I., Beukes, P., Romera, A. & Cichota, R. (2012). Estimating nitrous oxide emissions from a diary farm using a mechanistic, whole farm model and segregated emission factors for New Zealand. Soil Research 50 (3) 188-194

    Abstract

    Nitrous oxide (N2O) emissions from agriculture are generally estimated using default IPCC emission factors (EFs) despite the large variation in measured EFs. We used a classification and regression tree (CART) analysis to segregate measured EFs from direct emissions from urine patches and fertiliser and effluent applications, based on temporal and site-specific factors. These segregated EFs were linked to simulations from the DairyNZ Whole Farm Model to obtain N2O emissions for a typical pasture-based dairy farm in New Zealand. The N2O emissions from urine patches, dung pads, and fertiliser and effluent application, as well as from indirect sources, were aggregated to obtain total N2O emissions for the farm-scale. The results, based on segregated EFs, were compared with those obtained using New Zealand-specific EFs. On-farm N2O emissions based on these segregated EFs were 5% lower than those based on New Zealand-specific EFs. Improved farm management by avoiding grazing, effluent, and N fertiliser application during periods of high risk for N2O emissions, or by the use of mitigation technologies such as nitrification inhibitors, could reduce annual farm scale N2O emissions.

    Read more (external website)

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