Zealand Agriculture Research Articles

Using weather data to predict the presence of Lucilia spp. on sheep farms in New Zealand

Flystrike remains an important animal health issue on New Zealand sheep farms. To date no useful predictive tool to assist farmers to develop control options has been available. The aim of this study was to use National Institute of Water and Atmospheric Research (NIWA) virtual climate station data in New Zealand to develop a weather-based model to accurately predict the presence of Lucilia spp. on sheep farms throughout New Zealand. Three LuciTrap® baited fly traps were positioned on each of eight sheep farms throughout New Zealand (5 in the North Island and 3 in the South Island). The traps were put out for both the 2018–2019 and 2019–2020 seasons. They were emptied each week and the flies morphologically identified; with the counts of Lucilia cuprina and L. sericata combined as Lucilia spp. The count data for Lucilia spp. for each week of trapping was transformed into a binary outcome and a generalised linear mixed effects models fitted to the data, with farm as a random effect. The dependent variable was Lucilia spp. flies caught, yes or no, and the independent variables were mean weekly climate variables from the nearest NIWA virtual climate station to that farm. The model was trained on the 2018–2019 catch data and tested on the 2019–2020 catch data. A cut point was identified which maximised the model's ability to correctly predict whether Lucilia spp. were present or not for the 2019–2020 catch data, and the sensitivity, specificity, accuracy, and area under the curve (AUC) of the model calculated. The final model included just 3 significant variables, mean weekly 10 cm soil temperature, mean weekly soil moisture index, and mean weekly wind speed at 10 m. Mean weekly 10 cm soil temperature accounted for 64.7% of the variance explained by the model, mean weekly soil moisture index 34.7% and mean weekly wind speed at 10 m only 0.6%. The results showed that the predictive model had a sensitivity of 0.93 (95% CI = 0.80–0.98) and a specificity of 0.75 (95% CI = 0.62–0.85), using a cut point for the probability of Lucilia spp. being present on farm = 0.383. This model provides New Zealand farmers with a tool which will allow them to know when Lucilia spp. flies will likely be present and thus more accurately plan their interventions to prevent flystrike.

Royce Elliott – From empiricism to science-based policy in New Zealand agriculture

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Identification of risk factors for ewe mortality during the pregnancy and lambing period in extensively managed flocks

BackgroundEwe mortality during pregnancy and lambing is an issue for sheep producers globally, resulting in reduced productivity and profitability, compromised ewe welfare, and poor consumer perception. Despite these negative consequences, there was little investigation into factors associated with ewe death during this time. Therefore, this study aimed to assess associations between ewe body condition score (BCS), weight, reproductive parameters, and risk of mortality during pregnancy and lambing.MethodsFour cohorts from three commercial New Zealand farms participated, with 13,142 ewe lambs enrolled and followed over time. Data were collected for five consecutive lambings. Visits aligned with key on-farm management times, specifically: prior to breeding, at pregnancy diagnosis (PD), prior to lambing (set-stocking), and, at weaning of their lambs. At each visit, ewes were weighed, BCS assessed and reproductive status was recorded when relevant (litter size at PD and lactation status after lambing). Ewes that died or were culled were recorded, and any ewes that were absent from consecutive visits were presumed dead. Logistic regressions were developed to assess the relationship between weight and BCS at each visit, PD result (single or multiple-bearing) and lactation status (wet or dry) in each year, and, risk of mortality during the pregnancy and lambing period in each year.ResultsIn the PD to weaning period, mortality incidence ranged from 6.3 to 6.9% for two-tooth (18-months-old at breeding) to mixed-age (54-months-old at breeding) ewes. For ewe lambs (7 to 8-months-old at breeding), mortality was 7.3% from set-stocking to weaning. Heavier ewe lambs at PD were less likely to die during lambing (OR: 0.978, p = 0.013), as were those with greater set-stocking BCS. In subsequent years, BCS was a predictor of ewe death, with odds of mortality greatest for ewes < BCS 2.5. Additionally, for poorer BCS ewes, increasing weight reduced risk of mortality, but there was no impact of increasing weight in greater BCS ewes.ConclusionsThis study identified risk factors associated with ewe mortality during the pregnancy and lambing period. Flock owners can use these to either cull at-risk ewes or proactively intervene to reduce likelihood of mortality, thereby improving flock productivity, profitability and welfare.

Complete genomes of Pasteurella multocida isolates from porcine, bovine, and cervine samples found in New Zealand farms.

Here, we present complete genome assemblies of Pasteurella multocida strains isolated from porcine, bovine, and cervine farms as part of bacteriology incursion investigations to identify pathogens that might present a sanitary risk to New Zealand.

Ewe culling in New Zealand: an interview study of 38 farmers

ABSTRACT Removal of ewes from a flock before the end of their productive life, sometimes described as ewe wastage, can potentially lead to reduced flock productivity. While the main reasons for culling ewes are largely known, their relative importance to New Zealand farmers and farmers’ rational behind their culling decisions are not. Therefore, this study involved semi-structured interviews with 38 sheep farmers from throughout New Zealand to explore their ewe culling decisions. Farmers consistently culled mixed-age and two-tooth ewes who failed to become pregnant or who had a vaginal prolapse. For other culling reasons, farmers’ use of them and their rationale for doing so was diverse and varied between farmers based on ewe age-group, severity, season, perceived economic consequences and farmers’ personal preference. This diversity indicates that there is scope for some farmers to carefully evaluate some of their culling decisions.

The impact of a forage plant breeder – the story of Herrick Sydney (Syd) Easton (1946 - 2023)

Herrick Sydney (Syd) Easton was a forage plant breeder for 46 years. He bred at least 11 forage cultivars, in ryegrass, tall fescue and lucerne that were successfully licensed and commercialised, and he was a key part of the team that developed the successful Epichloë fungal endophyte products ‘Endosafe’, AR1, AR37, and ‘MaxP’ (‘MaxQ’ in USA). Syd’s development of measurement techniques and documentation of genetic variation for potentially valuable novel traits has been detailed in 130 refereed and significant publications, and he was an inventor or co-inventor of 13 patents and/or Plant Variety Rights. Syd made an important contribution in the understanding of endophyte-ryegrass interactions. Through his innovation and leadership, he led the multi-disciplinary AgResearch endophyte research programme, coordinating and writing the first successful funding application that consolidated the team. Coming from a farming family Syd connected with farmers and understood the value of highly supportive farmers and agricultural professionals who were able to critique, understand the value of and use the technologies and knowledge delivered from the science research he was involved with. Like many others in the agricultural research profession, he gained immense satisfaction from seeing technologies resulting from his research being used on New Zealand farms.

Predicting facial eczema risks in a changing New Zealand climate

Facial eczema is a major concern for New Zealand farmers due to its economic impact and animal welfare implications. The disease occurs when animals ingest sporidesmin, a mycotoxin produced by spores of the fungus Pseudopithomyces chartarum. Spore production is related to weather conditions; thus the incidence and severity of facial eczema varies between years, with thedisease commonly occurring from late summer through autumn in the North Island. We developed a simple model to estimate climatic suitability for P. chartarum sporulation and ran it using climate data for 2008-2021 to compare its estimates with spore counts from the same years. Model climatic suitability estimates had significant linear correlations with an index of exposure to spores derived from spore counts at both national and local scales. Model results were also consistent with a documented outbreak of facial eczema. Using predicted future climate data from the Hadley Centre Global Environment Model version 2 and two emissionsscenarios, the model suggested climatic suitability for P. chartarum sporulation will increase with time in many New Zealand regions, particularly in the southern North Island and eastern parts of the South Island. However, it could remain relatively static in some other areas, thus the degree of change in climatic suitability for P. chartarum sporulation is predicted to vary between New Zealand regions.

Factors Influencing Pastoral Farmers' Land-use Change Decisions in Response to Environmental Regulations in the Selwyn District, Canterbury

In recent years, the pressure placed on New Zealand farmers to reduce their environmental impact and convert to more sustainable land-uses has significantly increased in response to public and political concerns. This has seen an increase in the amount and complexity of environmental regulations, particularly for farmers in the Selwyn District, Canterbury. Increasing environmental regulations has contributed to an unintended side effect of a declining relationship quality between farmers and regulatory authorities.&#x0D; This study provides a new way for regulatory authorities to understand which factors influence pastoral farmers’ land-use change decisions and how these factors interact in response to environmental regulations. A total of nine pastoral farmers operating in the Selwyn District were interviewed to obtain data on how they made land-use change decisions and the impact of environmental regulations on these. Specifically, the data involved the collection of Q-sort scores, centrality scores, and the creation of causal maps.&#x0D; This study found that financial factors were the most important to pastoral farmers when making land-use change decisions. However, these financial factors were strongly connected to farmers’ sense of certainty around policy and practice. Many farmers felt unsure about the impact of current and future policy and practice changes on their farms. Subsequently, they felt hesitant to make land-use change decisions without the confidence that it will remain a financially and strategically viable choice for the longer term.&#x0D; This study also found that farmers had high intrinsic values surrounding environmental stewardship. Contrarily, environmental regulations drive land-use change decisions in an extrinsic form to farmers. This difference is concerning because if farmers become too focused on only doing what is required to meet regulations, it risks taking away the common-sense approach farmers already have. Overall, without improvements in the communication between regulatory authorities and farmers, the future may see increased focus by farmers on ticking boxes and less on strategically thinking about what is best for the environment.&#x0D; In summary, improved understanding by regulatory authorities and actions resulting from this will greatly contribute to positive environmental outcomes being reached in an efficient manner. To encourage sustainable land-use change, regulatory authorities need to give increased thought on how future regulations are created and implemented long-term. Farmers will feel more confident to transition to more sustainable land-uses with increased certainty around policy and practice and regulations that are introduced to them in a way that better understands their role as environmental stewards.

A framework for applying interceptive mitigations for diffuse agricultural pollution

ABSTRACT Interceptive mitigation options implemented at the edge of agricultural fields and along run-off and drainage flow-paths can complement preventive in-field management actions to reduce diffuse contaminant losses to surface waters. However, it is often unclear to users which interceptive mitigation option is appropriate for their situation, where it should be located, what contaminant reductions and other benefits can be achieved, and what it would cost to implement, maintain, and operate these practices. We outline a framework for selecting and applying eight interceptive diffuse pollution mitigation practices potentially applicable on New Zealand farms: riparian grass filter, planted and multifunction buffers; constructed wetlands; woodchip bioreactors; filamentous algal nutrient scrubbers; sediment traps; and detainment bunds. The framework provides users with a semi-quantitative evaluation of the relative benefits and costs of the best suited mitigations across a range of farmed landscapes. It highlights where each mitigation has its niche in terms of the landscape fit, flow-path(s) intercepted, contaminant(s) targeted, efficacy, associated co-benefits, relative cost, operation and maintenance requirements, longevity, and consenting requirements. Testing and refinement of this framework is encouraged, using data from field-scale implementation, to better quantify efficacy in practice, and inform empirical models and decision making across farm and catchment scales.

Heat Stress in French Bean and Garden Pea : A Review

This review paper addresses the effect of high temperature on pea and similar legumes. The areas covered are field pea and its production, temperature stress effects on New Zealand agriculture, seed vigour which discusses hollow heart and conductivity, high temperature stress on seed germination, threshold temperature, high temperature effects on vegetative growth and reproductive development. This is followed by adaptation mechanisms for high temperature stress, and breeding strategies which cover conventional plant breeding. The quality traits refer to protein, sugars, and the effects of high temperature on the grain composition and quality. Because of various factors related to global climate change, ambient temperatures are expected to rise in the future. Heat stress, which is a serious danger to crop output in most nations, can emerge from these temperature rises. Legumes are well-known for their nutritional and health benefits, as well as their impact on agricultural sustainability. Heat stress is a problem for legume crops because it affects the morphology, physiology, and reproductive growth of the plants. As grain legume agriculture grows to warmer areas and temperature fluctuation increases owing to climate change, high-temperature stress during the reproductive stage is becoming a serious constraint for output. The reproductive stage is critical in the life cycle of all plants, and it is vulnerable to high-temperature stress because many metabolic processes are harmed at this time, resulting in lower crop yields. Flower abortion, pollen and ovule sterility, decreased fertilization, and reduced seed filling are all observed in food legumes exposed to high-temperature stress during reproduction, resulting in smaller seeds and poorer yields. Heat tolerance in major legumes can be improved through several breeding approaches to improve field performance. Understanding the processes of molecular responses to high-temperature stress necessitates the use of omics methods to uncover the pathways behind thermo-tolerance.

Biocontrol of St John’s wort (Hypericum perforatum) provides huge ongoing benefits to New Zealand agriculture

ABSTRACT An ex-post economic evaluation of biocontrol of St John’s wort (SJW), Hypericum perforatum, in New Zealand (NZ), used ecological niche modelling, GIS-mapped land-use vulnerabilities and a logistic equation to predict that SJW could have infested 660,000 ha of low-value hill-country pasture. To calculate productivity losses, we assumed serious infestations of SJW caused 30% decreases in farm income per hectare. Investment in SJW biocontrol totalled NZ$0.28 million (2022 rates) associated with the 1943–1992 releases of the chrysomelid beetles, Chrysolina hyperici and C. quadrigemina, and the cecidomyiid gall midge, Zeuxodiplosis giardi. Biocontrol effectiveness increased linearly in our model from 1943 (when initial local defoliation occurred) to reach 99% control nationwide by 1993 (when SJW was no longer considered a significant agricultural weed). We estimate that SJW biocontrol in NZ provided a national benefit of NZ$15.5 million in 2022, with a historical benefit–cost ratio of 6254:1. Both figures remained large in sensitivity testing. Uncertainties remain concerning whether biocontrol caused all reductions in SJW, or whether SJW infestations were partially replaced by other weeds. Despite such caveats, benefits of SJW biocontrol to NZ appear huge and sustainable.

Molecular characterisation of the Australian and New Zealand livestock Chlamydia pecorum strains confirms novel but clonal ST23 in association with ovine foetal loss

Chlamydia pecorum is a veterinary pathogen associated with abortions and perinatal mortality in sheep. Recent studies investigating foetal and perinatal lamb mortality in sheep from Australia and New Zealand identified C. pecorum clonal sequence type (ST)23 strains in aborted and stillborn lambs. Presently, there is limited genotypic information on C. pecorum strains associated with reproductive disease, although whole genome sequencing (WGS) of one abortigenic ST23 C. pecorum strain identified unique features, including a deletion in the CDS1 locus of the chlamydial plasmid. We applied WGS on two ST23 strains detected in aborted and stillborn lambs from Australia and used phylogenetic and comparative analyses to compare these to the other available C. pecorum genomes. To re-evaluate the genetic diversity of contemporary strains, we applied C. pecorum genotyping, and chlamydial plasmid sequencing to a range of C. pecorum positive samples and isolates from ewes, aborted foetuses and stillborn lambs, cattle and a goat from diverse geographical regions across Australia and New Zealand.The two new C. pecorum genomes are nearly identical to the genome of the Australian abortigenic strain including the unique deletion in the chlamydial plasmid. Genotyping revealed that these novel C. pecorum ST23 strains are widespread and associated with sheep abortions on Australian and New Zealand farms. In addition, a goat C. pecorum strain (denoted ST 304) from New Zealand was also characterised. This study expands the C. pecorum genome catalogue and describes a comprehensive molecular characterisation of the novel livestock ST23 strains associated with foetal and lamb mortality.

The psychosocial impact of Mycoplasma bovis on southern New Zealand farmers: The human cost of managing an exotic animal disease incursion

Following the 2017 Mycoplasma bovis outbreak the New Zealand government decided to eliminate the disease from the national herd, something never attempted elsewhere. The present qualitative study aimed to explore the psychosocial impact on New Zealand farmers of the incursion and its management following this decision. Eighteen farmers and farming couples in southern New Zealand were interviewed about their challenging and sometimes harrowing experiences, including the lockdown of farms and subsequent loss of autonomy, stock culls, protracted cleaning of properties and negotiation for compensation. Farmers described their separation from typical farming practices as they transitioned into an incursion management process overseen by an ill-prepared government agency. Untimely and poor communication; lack of clarity about animal testing regimes; indecision regarding stock management; authoritarian and at times brutal decision-making concerning herd culls; and the ignoring of practical solutions to on-farm problems left farmers bewildered, angry and traumatised. Farmers spoke of their frustration at losing control of their properties and businesses, elements central to their identity. In emerging from the incursion, having replaced culled stock and resumed business, participants reflected on their changed farming practices, including greater attentiveness to biosecurity issues. They also reflected that relationships within rural communities, and between farmers generally and the state had transformed. Similar disease incursion experiences have been reported elsewhere and M. bovis is unlikely to be the last such event New Zealand experiences. Therefore, we conclude that paying close attention to the lessons learned from this event, including those related to process, communication, and valuing of famer knowledge and experience, will provide benefits to the sector generally, avoid injuriously impacting farmer wellness, and improve acceptance of future management strategies.

Characterization of glyphosate and AMPA concentrations in the urine of Australian and New Zealand populations

Glyphosate is the most used herbicide globally, but our understanding of human exposure and how different uses affect exposure is not well understood. The aim of this study was to obtain the first data on glyphosate and its primary degradation product aminomethylphosphonic acid (AMPA) concentrations in pooled and individual urine from the Australia and New Zealand region using a sensitive direct injection method and compare results with studies from elsewhere. Pooled urine samples from the Australian general population (n = 125 pools representing >1875 individuals) and individual urine samples (n = 27) from occupationally exposed New Zealand farmers were analysed by LC-MS/MS. Glyphosate was detected above the LOD (0.20–1.25 μg/L) in 8 % of the Australian population pooled urine samples with most detections in the 45–60 years age group. Furthermore, glyphosate (0.85 to 153 μg/L) and AMPA (0.50 to 3.35 μg/L) were detected in 96 % and 33 % of farmers, respectively. The maximum glyphosate urine concentration was 1.7 times above the recommended acceptable daily intake (ADI), when assuming a urinary excretion rate of 1 %. The pooled sampling and analysis approach proved effective for rapid large-scale screening of populations and could be used to determine where targeted and more specific individual sampling may be required.

Review and update of a Nutrient Transfer model used for estimating nitrous oxide emissions from complex grazed landscapes, and implications for nationwide accounting.

In New Zealand, nitrous oxide emissions from grazed hill pastures are estimated using different emission factors for urine and dung deposited on different slope classes. Allocation of urine and dung to each slope class needs to consider the distribution of slope classes within a landscape and animal behavior. The Nutrient Transfer (NT) model has recently been incorporated into the New Zealand Agricultural GHG Inventory Model to account for the allocation of excretal nitrogen (N) to each slope class. In this study, the predictive ability of the transfer function within the NT model was explored using urine deposition datasets collected with urine sensor and GPS tracker technology. Data were collected from three paddocks that had areas in low (<12°), medium (12-24°), and high slopes (>24°). The NT model showed a good overall predictive ability for two of the three datasets. However, if the urine emission factors (% of urine N emitted as N2 O-N) were to be further disaggregated to assess emissions from all three slope classes or slope gradients, more precise data would be required to accurately represent the range of landscapes found on farms. We have identified the need for more geospatial data on urine deposition and animal location for farms that are topographically out of the range used to develop the model. These new datasets would provide livestock urine deposition on a more continuous basis across slopes (as opposed to broad ranges), a unique opportunity to improve the performance of the NT model.

The frequency of tail damage amongst cows from a sample of New Zealand dairy farms participating in an animal welfare programme

ABSTRACT Aim To explore factors associated with the frequency of tail damage in dairy cows on 29 New Zealand farms participating in an animal welfare monitoring programme. Materials and methods Herd-level tail score data were collected at the cow level and then summarised at the herd level as counts for each lactation over the period 1 June 2014 to 31 May 2018. A cow’s tail was considered damaged if there was evidence of any injury that deformed the anatomical structure involving either bone or soft tissue and could include loss of use. There were four categories for tail scoring. Fracture or dislocation of tail bones was considered as a deviation (score 1). When the tail had been docked above the top of the cow’s udder, this was considered as docked short tail (score 2). When there was evidence of soft tissue trauma (score 3) or bone damage but no fracture (score 4), this was recorded as damaged (other). Tails were scored for each whole dairy herd. Tail scoring was performed by trained veterinarians or veterinary technicians. The primary outcome variable was counts of deviated tails (DT). Other outcome variables were docked short, damaged (other), and total tail injuries (TTI) which was a summation of all tail injuries. The potential predictor variables were area, season, farm, region, replacement rate, and herd size. A mixed-effects negative binomial or Poisson regression was fitted to the count data. Results A total of 29 farms contributed data for tail scoring, with 54,831 cows individually scored. The unadjusted regional prevalence of TTI ranged from 3.5% (64/1,835) in Taranaki in 2014–2015 to 28.7% (1,434/4,988) in Southland/Otago in 2017–2018. The unadjusted regional herd prevalence of DT ranged from 2.1% (280/6,862) in Taranaki (2014–2015) to 13.2% (4,627/30,165) in Southland/South Otago (2017–2018). The incident rate ratio (IRR) of DT in 2015–2016 was 1.74 (95% CI = 1.20–2.53; p = 0.003) times the incident rate for the reference group (2014–2015). The IRR for TTI in 2015–2016 was 1.70 (95% CI = 1.60–1.81; p = 0.001) times the incident rate for the reference group (2014–2015). Conclusions and clinical relevance This is the first quantitative study of the frequency of tail damage within New Zealand dairy farms and whilst variable between regions, it indicates that the frequency is increasing. Opportunities exist to better understand the causes of tail injuries and to improve animal welfare.

Facilitating the wise use of experts and evidence to inform local environmental decisions

Abstract Using biodiversity management within New Zealand's agricultural landscape as a case study, we apply ‘boundary science’ approaches to overcome two persistent deficiencies in environmental decision‐making: ‘evidence disparity’, the discrepancy between evidence desired and evidence generated, and ‘evidence complacency’, where evidence is not sought or used, or is out of date, incomplete or biased. Specifically, we assess how recent innovations in gathering, evaluating and communicating of evidence syntheses can: give local stakeholders from a diversity of roles and interests a voice in setting biodiversity priorities, systematically tailor global evidence to meet local needs and make wise use of local biodiversity specialists to enhance the accuracy and reliability of their judgements. Initial case study material comprised comprehensive lists of 18 biodiversity outcome groups and 84 management actions of potential value to New Zealand farms. Of the 40 management actions that mattered most to stakeholders, 90% of actions required editing in preparation for the expert assessments. The final list of priorities encompassed 43 management actions and 11 biodiversity groups. New Zealand evidence gaps were detected for the two actions and 10 biodiversity groups assessed, with half of these gaps plugged using global studies. Six experts then systematically evaluated this evidence to tailor its interpretation to the local context, mitigating the risks of using different evidence subsets and evaluation criteria. The effectiveness of each action in delivering biodiversity benefits was also assessed by a panel of 10 experts using their specialist judgement to mitigate the risks of: (a) a skewed assessment derived from one or two experts; (b) overwhelming panellists with a long list of issues to debate; and (c) conflicts arising from misunderstandings about action outcomes. The stakeholder priorities delivered useful insights, which could be used to direct and facilitate inclusive policy investments beyond our project. Auditing local studies using existing evidence synopses is recommended to help improve local conservation evidence bases. Our study highlights the crucial role that a boundary‐spanning team can play in gathering, organising, summarising and integrating datasets to address evidence disparity and complacency issues affecting local biodiversity management decisions required by global policy. Read the free Plain Language Summary for this article on the Journal blog.

Simulating use of terminal sires in a self-replacing beef suckler herd with varying weaning rate, calf sale policies, and price premiums

New Zealand farmers can choose to breed a proportion of their beef cow breeding herd with terminal breed sires to produce heavier offspring to sell for higher per head prices. However, the heavier weights of terminal offspring also increase their feed demand which may necessitate cow herd size reductions in a system with a fixed feed supply. This study used a bio-economic, system dynamics model to simulate cattle numbers, production, and beef enterprise cash operating surplus (COS) for a self-replacing beef suckler herd of Angus breed cows bred with only Angus sires to produce purebred offspring or a proportion of cows bred with European breed terminal sires (such as Charolais or Simmental). The herd was also modelled with varying calf weaning rates (84 or 90%), with offspring sales occurring either at weaning or at 27 months of age, and in a secondary analysis, with or without price premiums for sales of cattle of at least 75% Angus breed. Total annual beef feed demand was maintained at 40% of total farm feed supply (total farm area of 530 ha) in all scenarios, with the remainder consumed by the on-farm sheep flock. Beef enterprise COS was therefore divided by the beef herd proportion of farm area (212 ha) to derive a per ha COS value. Herd replacement rate was first modelled at 22% allowing for 43% of cows to be bred with terminal sires with a weaning rate of 84%. With a weaning rate of 90% the replacement rate was 18% allowing 60% of cows to be bred with terminal sires. The base scenario with a herd weaning rate of 84% using only Angus sires had a COS of NZD 255 /ha. Relative to the base scenario, use of terminal sires increased COS by the largest amount (COS = NZD 317 /ha), Angus premiums increased COS by a lower amount (COS = NZD 307 /ha), and the higher weaning rate of 90% increased COS by a slightly lesser amount (COS = NZD 302 /ha). Alternatively, these strategies could be implemented concurrently, which was predicted to have the highest COS at NZD 381/ha. These results can inform farmer decision making and farmers can consider the relative profitability potential and practicality of the explored strategies for their breeding herd.

Soil moisture and expectations regarding future climate: evidence from panel data

The literature on belief regarding climate is extensive, with results showing that both personal characteristics and personal experience with the effects of climate change strongly influence future expectations. The vast majority of studies rely on cross-sectional data, making it difficult to ascertain the durability of expectations regarding future climate or the effect of additional environmental cues on beliefs. A few panel studies of which we are aware exploit extreme weather events to find evidence of “confirmation bias”, in which additional environmental signalling reinforces existing beliefs. In contrast, we evaluate how normal fluctuations in soil moisture causally impact expectations of future drought using a panel of New Zealand farmers. We find that environmental cues such as soil moisture scarcely affect expectations of respondents who already expected future drought to increase but that soil moisture strongly influences respondents who did not. In particular, drier soils are associated with higher expectations of future drought among these former sceptics, whether they previously believed that future drought would decrease or simply would not change. Thus, as New Zealand moves toward IPCC forecasts of more frequent and more severe drought, farmers, foresters, and growers will increasingly agree with the scientific consensus, raising the likelihood of both farm-level and public action.

The development of Pallaton Raphanobrassica for New Zealand farming systems

‘Pallaton’) is an allotetraploid, produced from kale(Brassica oleracea L.) x radish (Raphanus raphanistrumsubsp. sativus L.). It is a multi-graze forage, selected forhigh cumulative yield, water efficiency and resistanceto clubroot (Plasmodiophora brassicae). This paperdescribes the breeding, agronomy and nutritive valueof ‘Pallaton’, which can be grazed in situ between42 and 70 days after sowing (DAS) with no specificcrop maturity requirement. Cumulative yield of threeconsecutive harvests, analysed by meta-analysisof eighteen trials from 2013 to 2019 on three sites,showed ‘Pallaton’ had a greater yield of 16,254 kg DM/ha than forage rape (B. napus spp. biennis, cv. ‘Titan’)and leafy turnip (B. rapa; syn. B. campestris cv. ‘PasjaII’) at 12,639 and 10,965 kg DM/ha, respectively. Afurther trial, comparing nutritive values, demonstrated‘Pallaton’ has a similar profile to ‘Titan’. ‘Pallaton’ maybe rotationally grazed for up to twelve months wheninitially grazed by livestock at 350 - 400 mm plantheight between 42 and 70 DAS. Livestock consuming‘Pallaton’ are susceptible to the same potential animalhealth concerns as other Brassica species, but representsa forage option for sheep, beef, deer and dairy farming,particularly those in challenging environments.