Zealand Agriculture Research Articles

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.

Radium in New Zealand agricultural soils: Crop uptake and estimation of current and future ionising radiation dose

Crop uptake of 226Ra over a range of key New Zealand agricultural and horticultural growing areas was analysed to establish the dietary implications of an increase in soil 226Ra activity concentrations. Thirty crop samples, covering both feed and food commodities, were quantified for 226Ra activity concentrations, and concentration ratio (CRs) from the soil activity were calculated. The calculated CRs correlated with international default values for estimating crop uptake. Variation in CRs established that there was no increase in the crop activity concentration, relative to soil 226Ra from pasture foliage at a fertiliser impacted site, with a gradient of soil 226Ra activity concentrations. Based on the calculated CRs, the upper bound of the theoretical range of dietary exposures to 226Ra was 78.1 μSv/yr for teenage boys. Future forecasting of the increased dietary dose of 226Ra that might occur at the current soil loading rate, based on current fertiliser activity concentrations, confirmed that long-term loading of soil with 226Ra is unlikely to present a dietary risk. The forecast model calculated that the increase in dietary ionising radiation burden is unlikely to reach thresholds requiring regulatory intervention for two millennia.

Organising Committee Chair's address: Resilient pastures

High value animal products from New Zealand’s pasture-based livestock systems have consistently earned $25-$30B in export earnings per year for the country over the past 5 years (Ministry for Primary Industries 2021). Total earnings from dairy and meat of $30.5B in 2020 equate to 35% of New Zealand’s total goods and services export earnings of $86.4B. The importance of this revenue to the national economy has been shown in stark relief recently with the Covid-19 pandemic substantially reducing the earnings generated by other key export sectors such as tourism and international education. While our pasture-based livestock industries have ridden the coronavirus wave well compared with other sectors of the economy, they are facing change at a scale and pace not seen since the far-reaching reforms to the economic settings for agriculture introduced by the Lange Government in the early 1980s. Locally, the ramping-up of government environmental policies beginning c. 2011 has resulted in stringent regulations controlling the amounts of nitrogen (N), phosphorus (P) and sediment that can be discharged into freshwater from farm systems. The most recent iteration in this policy sequence includes new National Environmental Standards for Freshwater, and the new National Policy Statement for Freshwater Management (NPS-FW), which came into force in September 2020. These policies reverse the trends of the past two decades when agricultural productivity grew substantially in the virtual absence of regulation to control the environmental externalities of systems intensification. While the initial impacts on land use and farming practices have been localised (e.g., in the lake districts of Rotorua and Taupo), disruption to the farm systems that have emerged over the past two decades, especially intensive dairy systems, will be widespread in the future. For example, Doole et al. (2021) estimated that the new standards introduced in 2020 will require about 40% of New Zealand’s 11400 dairy farms to reduce nitrate leaching by an average of around 42% relative to requirements in previous iterations of the NPS-FW. The most significant global force driving change in New Zealand agriculture is climate change, via New Zealand’s commitment to the Paris Agreement to reduce carbon (C) emissions to net zero by 2050, C-neutral strategies being implemented by some of our largest customers (e.g., Nestle 2020), and the physical impacts of climate change on conditions for plant growth (e.g., Keller et al. 2021). Of direct and significant relevance to the livestock industries are the methane emission reduction targets proposed by government, of between 27% and 47% below 2017 levels by 2050. Meanwhile our international competitors have been steadily closing the gap in costs of production with New Zealand, and now have other fields on which to out-compete us (e.g., in C footprint) unless we can keep pace.

Behavioural insights for improved uptake of agricultural sustainability assessment tools

Abstract Changing human behaviour to enhance agricultural sustainability outcomes is an ongoing challenge that urgently needs addressing. It requires identifying the mechanisms for the successful uptake and application of tools and behavioural interventions to mitigate the detrimental impacts of farm activities on the environment. We combined a participatory action research and mixed‐methods approach (via online surveys, workshops, seminars, meetings and emails) to work with diverse stakeholders to understand their perspectives on the following: (a) sharing farm biodiversity data; (b) behavioural factors likely to influence farmer uptake and use of a farm‐level sustainability assessment tool developed for New Zealand farms; and (c) how to improve the tool. Respondents (n = 133) to an online survey were most willing to share data to gain advice on improving farm practices, but least willing when farmers were paid for the data, or companies used it to market products to farmers. Respondents were most comfortable with sharing data when an independent board decided the data‐use policies, or the contributor could change their sharing preferences and data were anonymised. Feedback on the tool prototypes was elicited via 27 events and more than 133 individual interactions. Of the 529 alignments between 255 discussion points and 14 behavioural factors, almost half were centred on the material context (e.g. infrastructures, technologies, time and schedules) but were often coupled with individual and social factors. Overall, a strong desire for a tool that empowers individual farmers to enhance their farm's biodiversity outcomes emerged, although, during the initial prototype tests, the tool's strengths were rarely acknowledged and concerns about weaknesses were more common. Ten strategies were identified for enhancing the tool. These aligned closely with three human‐thinking principles: four strategies focused on thinking automatically, three on thinking socially and seven on thinking using mental models. The system transformations required to implement such an integrated package of interventions to change behaviour at scale include a collective approach to developing a stronger evidence base for conservation actions, and behavioural interventions to enhance social and environmental capital in production landscapes. Read the free Plain Language Summary for this article on the Journal blog.

Ontology-Based Semantic Search Framework for Disparate Datasets

The public sector provides open data to create new opportunities, stimulate innovation, and implement new solutions that benefit academia and society. However, open data is usually available in large quantities and often lacks quality, accuracy, and completeness. It may be difficult to find the right data to analyze a target. There are many rich open data repositories, but they are difficult to understand and use because these data can only be used with a complex set of keyword search options, and even then, irrelevant or insufficient data may eventually be retrieved. To alleviate this situation, ontology-based semantic search has been proven to be an effective way to improve the quality of related content queries in such repositories. In this paper, we propose a new method of semantic linking and storing open government datasets of New Zealand's agriculture, land and rainfall sectors based on the use of ontology. The generated ontology can construct integrated data, in which a unified query can be applied to extract richer and more useful information. To validate our model, we showed how to link ontology manually and automatically. Manual linking requires domain experts, and automatic linking reduces the overhead of relying on domain experts to manually link concepts. The results of this method are promising in terms of improving data quality and search efficiency. In future, the proposed model can be integrated with other domain ontologies.

Pathways towards evidence-based decision-making for improving New Zealand farm sustainability

More incorporation of scientific evidence, and better prioritisation of interventions, might improve the performance of agri-environmental schemes. Data simulations using a biodiversity tool for New Zealand farms highlight the penalties of failing to prioritise farm interventions and refine industry-wide biodiversity management targets in relation to socially licensing farming, encouraging investment and participation by all stakeholders, and securing sustainable food and fibre production. Evidence informing these simulations included: 43 actions and 11 biodiversity groups systematically prioritised by stakeholders; biodiversity weights independently assigned to each action via a structured evaluation by 10 biodiversity experts; and the baseline distribution of biodiversity refuges on farms, reflecting their observed incidence in New Zealand's production landscape. Prioritisation across the demonstration industry halved the number of actions that would be required to deliver a 3-fold biodiversity gain. The greatest gains were made in the first 2 years when implementing all possible actions over 10 years. If every farm across the demonstration industry prioritised and implemented a quarter or more of possible actions, all would meet a biodiversity performance target of 10% improvement within 7 years. Adding biodiversity refuges is needed for 30% improvement in biodiversity for all farms within 10 years. The modelling encourages and informs investments by building confidence in the longer-term value of continuous farming improvements. The simulations give users confidence they are choosing the best options for their own circumstances, thus providing positive mental models for overcoming evidence complacency and incentivising behaviour changes crucial for delivering desired biodiversity outcomes. Evaluating other sustainability benefits and estimating costs of each biodiversity intervention are the logical next steps to encourage uptake and to fine-tune and optimise strategies for industry-wide biodiversity care and multifunctional agricultural using the simulation tools reported here.

Less is more? Ultra-low carbohydrate diet and working dogs' performance.

New Zealand farm working dogs are supreme athletes that are crucial to agriculture in the region. The effects that low or high dietary carbohydrate (CHO) content might have on their interstitial glucose (IG) and activity during work are unknown. The goals of the study were to determine if the concentration of IG and delta-g (a measurement of activity) will be lower in dogs fed an ultra-low CHO high fat diet in comparison to dogs fed a high CHO low fat diet, and to determine if low concentrations of IG are followed by reduced physical activity. We hypothesized that feeding working farm dogs an ultra-low CHO diet would reduce their IG concentrations which in turn would reduce physical activity during work. We prospectively recruited 22 farm dogs from four farms. At each farm, dogs were randomized to one of two diets and had a month of dietary acclimation to their allocated diet. The macronutrient proportions as a percentage of metabolizable energy (%ME) for the high CHO low fat diet (Diet 1) were 23% protein, 25% fat, and 52% CHO, and for the ultra-low CHO high fat diet (Diet 2) 37% protein, 63% fat, and 1% CHO. Following the acclimation period, we continuously monitored IG concentrations with flash glucose monitoring devices, and delta-g using triaxial accelerometers for 96 h. Dogs fed Diet 2 had a lower area under the curve (±SE) for IG (AUC Diet 2 = 497 ± 4 mmol/L/96h, AUC Diet 1 = 590 ± 3 mmol/L/96h; P = 0.002) but a higher area under the curve (±SE) for delta-g (AUC Diet 2 = 104,122 ± 6,045 delta-g/96h, AUC Diet 1 = 80,904 ± 4,950 delta-g/96h; P< 0.001). Interstitial glucose concentrations increased as the activity level increased (P < 0.001) and were lower for Diet 2 within each activity level (P < 0.001). The overall incidence of low IG readings (< 3.5 mmol/L) was 119/3810 (3.12%), of which 110 (92.4%) readings occurred in the Diet 2 group (P = 0.001). In the Diet 2 group, 99/110 (90%) of the low IG events occurred during the resting period (19:00-06:00). We conclude that feeding Diet 2 (ultra-low CHO high fat diet) to working farm dogs was associated with increased delta-g despite decreased IG concentrations. Interstitial glucose concentrations were positively associated with dogs' activity levels independent of diet. Lastly, events of low IG occurred at a low incidence and were predominantly seen between 19:00-06:00 in dogs fed the ultra-low CHO high fat diet.

Giving stakeholders a voice in governance: Biodiversity priorities for New Zealand's agriculture

Abstract Mainstreaming biodiversity across government and society is recognised by international policy as critical to achieving positive conservation outcomes. With ‘participatory governance’ increasingly being applied to achieve collective action in conservation, there are growing calls to critically review such processes to capture their complexity and manage for emergent outcomes. This paper critically reviews a case study, aiming to give a broad range of stakeholders a voice in setting biodiversity priorities for New Zealand's agricultural landscape, in relation to four principles for knowledge co‐production in sustainability: context‐based, pluralistic, goal‐orientated and interactive. Aiming to facilitate an inclusive but rapid participation process, while not overburdening those willing to participate, three pathways for engagement were offered. Stakeholder participants were recruited from public, private and civic sectors involved in managing New Zealand's farmland biodiversity. An initial scoping exercise helped elevate biodiversity groups and management actions distinct to New Zealand's social and environmental context. Online surveys then gave stakeholders, from a diverse range of roles and sectors, a nationwide voice to express their own biodiversity interests and needs; these were reviewed by an advisor panel to reach consensus on final priorities that reflected the biodiversity outcomes that matter most to stakeholders involved in managing New Zealand's agricultural landscape and the management practices they considered most relevant to achieving those outcomes. This knowledge co‐production process delivered multiple gains that would not have been achieved had a more traditional science‐based process been applied, such as wide stakeholder engagement, identification of a tangible starting point, mitigation of bias or conflict risks, enhanced researcher and practitioner capabilities and a shared understanding of the opportunities and challenges for future development. Institutes addressing conservation challenges within local contexts need to: be ‘boundary‐spanning’ to manage cross‐scale influences and enable desired conservation behaviours; plan explicitly for the substantial effort required to overcome existing power hierarchies and facilitate transparent and structured decision processes that deliver social justice; better capture the relational values of nature to more successfully leverage peoples’ connection to nature in conservation policies and practices; and incorporate wider environmental (e.g. biosecurity), social, economic and political considerations. A free Plain Language Summary can be found within the Supporting Information of this article.

Factors Associated with Ewe Death and Casting in an Extensively Farmed Sheep Flock in New Zealand

Ewe deaths affect the productivity and profitability in sheep farming systems and have potential animal welfare and market perception implications. Internationally, there is scant data on the timing and causes of ewe deaths in extensive grazing systems. There is no published literature on the incidence and risk factors associated with casting (ewe in late gestation accidentally immobilised, often in dorsal recumbency). This study, undertaken using a cohort of 1789 ewes on a New Zealand farm, reports on the timing and risk factors associated with production parameters for ewe deaths through an almost two-year period, along with causes of death during both peripartum periods. Ewe deaths occurred throughout both years but were most frequent during the peripartum (pre-lambing to mid-lactation) period. Casting was the most commonly identified cause of death in both years, responsible for approximately a quarter to a third of potential annual mortality. Few risk factors for death or casting were identified. In conclusion, the peripartum period is a high-risk time period for ewe deaths (and, by extension, will also contribute to lamb perinatal mortality). In extensively grazed flocks where casting events occur, it is recommended that all ewes are monitored daily during the peripartum period.

Estimated Breeding Values of Beef Sires Can Predict Performance of Beef-Cross-Dairy Progeny.

On average, half of the animal’s estimated breeding value (EBV) is passed on to their progeny. However, it is not known how the performance of beef-cross-dairy cattle relates to the EBV of their beef sire. Such information is required to determine the genetic potential of beef sires selected based on existing EBV to be used on dairy cows in New Zealand. This study evaluated the relationship between the EBV of 30 Angus and 34 Hereford sires and the performance of their progeny for birth, growth, and carcass traits, via progeny testing of 975 beef-cross-dairy offspring born to dairy cows and grown on hill country pasture. Overall, BREEDPLAN EBV did predict progeny performance of the beef-cross-dairy cattle from this study. Gestation length and birthweight increased with increasing sire EBV (mean 0.37–0.62days and 0.52–0.64kg, respectively, p<0.05). Age at weaning decreased with increasing sire EBV for liveweight at 200days (0.17–0.21days per extra kilo of sire EBV, p<0.05) but sire EBV for liveweight at 200days had no effect on the liveweight of the progeny at 200days for either breed (p>0.05). Liveweight increased with sire EBV for liveweight at 400, 600, and 800days, by a similar amount for both breeds (between 0.23 and 0.42kg increase in progeny liveweight per extra kilo of sire EBV, p<0.05). The relationships were more inconsistent for carcass traits. For Hereford, carcass weight and eye muscle area increased with increasing sire EBV (0.27kg and 0.70cm2, respectively, p<0.05). For Angus, marble score increased by 0.10 with 1% extra in sire EBV for intramuscular fat (p<0.05). Rib fat depth tended to increase with sire EBV for both breeds (p<0.1). EBV derived from beef-breed data work in dairy-beef systems but maybe slightly less than the expected 0.5units of performance per unit of EBV. New Zealand farmers should consider BREEDPLAN EBV when selecting sires to mate dairy cows or when buying beef-cross-dairy calves for beef production, to ensure the resulting calves are born safely and on time and then grow well to produce carcasses of suitable meat and fat composition.

A Field Evaluation of the LuciTrap and the Western Australian Trap with Three Different Baits Types for Monitoring Lucilia cuprina and Lucilia sericata in New Zealand

Simple SummaryIn New Zealand, flystrike is caused by two Dipteran species, Lucilia cuprina and Lucilia sericata. This study contrasts four flytrap treatments, the LuciTrap with its combination of three chemical lures (Lucilures) and the Western Australian Trap with three different bait types (LuciLure, Sheep liver with 30% sodium sulphide and squid) during mid-summer. The aim of the study is to assess the most effective trap and bait combination that New Zealand farmers may use on their farms to monitor L. cuprina and L. sericata. This study found that either the LuciTrap or the Western Australian Trap with sheep liver and 30% sodium sulphide were the most effective traps to catch L. cuprina and L. sericata.Flytraps can be used on farms to monitor the populations of primary strike flies (Lucilia cuprina and Lucilia sericata) and, hence, offer a view regarding the incidence of flystrike on sheep. This study aimed to contrast the specificity and effectiveness of the LuciTrap with its combination of three chemical lures (Lucilures) and the Western Australian Trap with three bait types (LuciLure, Sheep liver with 30% sodium sulphide and squid). A mean model and rate model were fitted to the data. The mean model showed no difference (p > 0.05) in the mean weekly catch for L. cuprina between the Western Australian Trap with LuciLures and the Western Australian Trap baited with sheep liver with 30% sodium sulphide (p < 0.05). Whereas, for L. sericata, no difference (p > 0.05) was found between the Western Australian Trap with LuciLures, the Western Australian Trap baited with sheep liver with 30% sodium sulphide and the LuciTrap. The rate model illustrated that the Western Australian Trap with sheep liver with 30% sodium sulphide and LuciTrap did not differ (p > 0.05) for L. cuprina and L. sericata. Combined, these results indicate that New Zealand farmers can use either the LuciTrap or the Western Australian Trap with sheep liver with 30% sodium sulphide to monitor these target species.

Genetic Parameters for Maternal Performance Traits in Commercially Farmed New Zealand Beef Cattle.

Simple SummaryEnhancing maternal performance in a beef cattle enterprise can increase overall profitability. Knowledge of the degree of genetic variation in relevant traits is required to inform breeding decisions in commercial environments. The objective of this research was to examine the inheritance of maternal performance traits and to evaluate the trait complementarity among reproduction, live weight, hip height, body condition score and maternal weaning weight in 15-month-old heifers, 2-year-old cows and mature cows using data collected on commercial New Zealand hill country farms. Results from this study indicate that almost no genetic variation exists for pregnancy outcomes in 15-month-old heifers and mature cows under New Zealand farming conditions but there is potential to improve reproductive performance in 2-year-old cows through genetic selection. Cows with greater genetic potential for rebreeding performance after their first calving season were more likely to have greater live weight, hip height and body condition score as heifers but were unlikely to become larger cows at maturity. Cows with genetics for greater maternal weaning weight were more likely to carry lower body condition and those animals tended to show greater reproductive performance.Maternal performance is a major driver of profitability in cow-calf beef cattle enterprises. The aim of this research was to evaluate the inheritance of maternal performance traits and examine the intercorrelation among reproduction, live weight, hip height, body condition and maternal contribution to calf weaning weight in 15-month-old heifers, 2-year-old cows and mature cows in New Zealand beef herds. Data were collected on a total of 14,241 cows and their progeny on five commercial New Zealand hill country farms. Heritabilities were low for reproductive traits in heifers and mature cows (0–0.06) but were greater in 2-year-old cows (0.12–0.21). Body condition scores were lowly (0.15–0.26) and live weights (0.42–0.48) and hip heights (0.47–0.65) highly heritable in heifers, 2-year-old cows and mature cows. Results indicate that 2-year-old cows with higher genetic potential for rebreeding ability may have greater genetic merit for live weight, hip height and body condition as heifers (rg = 0.19–0.54) but are unlikely to be larger cows at maturity (rg = −0.27–−0.10). The maternal genetic effect on weaning weight had a heritability of 0.20 and was negatively genetically correlated with body condition score in lactating cows (rg = −0.55–−0.40) but positively genetically correlated with rebreeding performance (rg = 0.48).

Simplified methods for on-farm prediction of yield potential of grazed lucerne crops in New Zealand

ABSTRACT Analyses of New Zealand farm systems require estimates of herbage yield and quality. These are available for perennial ryegrass and white clover pastures but not for other common pasture species. We used five lucerne datasets to derive functional relationships between growth rate and temperature. This required three functions to account for partitioning in lucerne between spring and autumn and differences between seedling and regrowth crops. The maximum mean daily growth rate of 206 ± 5.95 kg DM/ha/d occurred with full canopy cover at mean air temperatures between 15°C and 22°C. This represents the upper end of the temperature range available. The relationship was summarised into a matrix that could be incorporated into existing forage forecasters for farm system analyses. Alternatively, a simplified model assessed growth rate in relation to thermal time. This showed after 140°Cd accumulated from 1 July, lucerne initiated spring growth at 11.9 kg DM/ha/°Cd until mid-January and then decreased to 6.7 kg DM/ha/°Cd from mid-January to 30 June for fully irrigated crops. An exponential heightchron relationship was also calculated to estimate crop height based on the thermal time required per mm as photoperiod changed. This relationship allows lucerne quality to be predicted from the leaf:stem ratio.

Live weight and body condition score of mixed-aged beef breeding cows on commercial hill country farms in New Zealand

ABSTRACT Extensive farming systems require beef cows to cope with varying environmental conditions while repeatedly producing calves. Cows use body energy reserves as a buffer in times of feed shortage and replenish reserves under a feed surplus. The aims of the research were to (1) quantify live weight (LW) and body condition score (BCS) fluctuations among farms, years and over the production cycle (mating, weaning and calving) and to (2) quantify the relationship between LW and BCS at mating, weaning and calving, for cows of different hip heights. A total of 7,649 individual cow records from nine commercial New Zealand farms with information on LW and BCS (1–10 scale, 1 = emaciated and 10 = obese) were analysed. Analyses revealed significant (P < 0.001) within-year variation in mean LW (32.4–77.2 kg) and BCS (0.4–1.8 scores) profiles among farms, but profiles were not consistent from year to year. There was a quadratic relationship (P < 0.001) between LW and BCS, such that one unit change in BCS corresponded to 15.1 kg LW increase at BCS 4–5 compared to 41.1 kg LW increase at BCS 8–9 at mating. This relationship was similar, irrespective of hip height.

Ewe Wastage in New Zealand Commercial Flocks: Extent, Timing, Association with Hogget Reproductive Outcomes and BCS.

Simple SummaryEwe wastage is the combination of on-farm mortality and premature culling. Increased wastage results in a reduction in flock productivity and profitability, yet internationally, there is limited research on actual wastage incidence and causes in commercial flocks. This study reports both lifetime wastage and detailed annual wastage for 13,142 ewes from four cohorts on three commercial New Zealand farms. This study also describes the relationship between ewe pre-mating body condition score and wastage. Of the 13,142 enrolled ewes, 50.4% and 40.0% exited their respective flocks due to premature culling and on-farm dead/missing, respectively. Annual mortality incidence ranged from 3.5 to 40.2%. Wastage as a hogget was identified as an area in which improvements can be made to reduce overall wastage. Pre-mating body condition score was a predictor of wastage, with ewes with greater pre-mating body condition score having lower odds of wastage due to both premature culling and mortality. Therefore, farmers should focus on improving the body condition score of their ewes prior to breeding.Ewe wastage is the combination of on-farm mortality and premature culling. Internationally, there is limited research on actual wastage incidence and causes in commercial sheep flocks. To the authors’ knowledge, this is the first study that reports both lifetime wastage and detailed annual wastage in a sample of commercial New Zealand flocks. This study utilized data collected from 13,142 ewes from four cohorts on three commercial New Zealand farms (Farm A 2010-born, Farm A 2011-born, Farm B, Farm C), during the period 2011–2017, as they aged from replacement hoggets to 6-year-old ewes (Farm A and Farm B) or 3-year-old ewes (Farm C). Data collection visits occurred at three or four key management times each year, namely pre-mating, pregnancy diagnosis, pre-lambing and weaning. At each visit, body condition score (BCS) was assessed and any ewes that were culled or had died on farm were recorded. As this was a lifetime study, each ewe was assigned an outcome and corresponding ‘exit age’. By the end of the study, all ewes that had exited their respective flocks, were classified as either prematurely culled, or dead/missing, or if still in the flock, as censored, and either the exact date or interval in which they exited the flock was recorded. Semi-parametric competing risk (premature culling vs. dead/missing), interval-censored survival models were developed to: 1. describe the association between hogget reproductive outcomes and risk of subsequent wastage, and 2. assess pre-mating BCS as a predictor of wastage in that production year. Of the 13,142 enrolled ewes, 50.4% exited their respective flocks due to premature culling and 40.0% due to on-farm dead/missing, giving a total of 90.4% that exited due to wastage. Annual mortality incidence ranged from 3.5 to 40.2%. As a hogget, wastage incidence ranged from 7.6 to 45.4%. Pregnancy or rearing a lamb as a hogget did not increase risk of subsequent wastage. In all years, pre-mating BCS was a predictor of ewe wastage, with odds of wastage lower with increasing BCS. Therefore, farmers should focus on improving pre-mating BCS to 3.5/5.0 by assessing ewe BCS at weaning, allowing poorer-BCS ewes to be managed to gain BCS before re-breeding.

New-generative agriculture – based on science, informed by research and honed by New Zealand farmers

Highlights&#x0D; &#x0D; Regenerative agriculture is being promoted as a way to produce food sustainably while building soil carbon under high residual rotational grazing and minimising environmental impact.&#x0D; Research indicates that the environmental impact of conventional agricultural systems is generally lower than for alternative systems per unit of food production and sometimes per hectare. Soil carbon is higher under well-managed intensive grazing than under extensively managed systems. Adopting non-optimal grazing management decreases pasture quality and increases GHG and N losses.&#x0D; New Zealand has developed optimal rotational grazing and has soils with high organic-matter contents. Rather than adopting a concept developed overseas which has a fluid definition, New Zealand could promote New-generative agriculture… encapsulating what is already being done.&#x0D;

A Review and Update of the Nutrient Transfer Model Used for Estimating Hill Country Nitrous Oxide Emissions in the New Zealand Agricultural Greenhouse Gas Inventory Model

A Review and Update of the Nutrient Transfer Model Used for Estimating Hill Country Nitrous Oxide Emissions in the New Zealand Agricultural Greenhouse Gas Inventory Model

Serological study of Leptospira interrogans serovar Copenhageni and L. borgpetersenii serovars Tarassovi and Ballum in beef cattle, sheep and deer in New Zealand

ABSTRACT Aims To estimate animal-level seroprevalence of Leptospira interrogans serovar Copenhageni and L. borgpetersenii serovars Ballum and Tarassovi, in beef cattle, sheep and deer on New Zealand farms, and herd/flock-level seroprevalence of any serovar when existing same-sera data for serovars Hardjobovis and Pomona were included, and to determine associations between risk factors and animal-level seroprevalence. Methods Banked sera from sheep (n = 82), beef (n = 54) and deer (n = 62) herds/flocks (n = 3,878 animals) from seven regions were analysed using the microscopic agglutination test. Titres of ≥48 were designated positive. Herds/flocks were considered positive if either ≥1, ≥2 or ≥3 animals were positive. Existing same-sera data for serovars Hardjobovis and Pomona were included to establish farm-level any-serovar seropositivity. Factors associated with serological status were analysed using generalised estimating equations. Results Animal-level seroprevalence for serovars Ballum, Copenhageni, and Tarassovi, respectively, was 13.7 (95% CI = 11.7–16.0)%, 12.6 (95% CI = 10.6–14.7)% and 18.0 (95% CI = 15.7–20.5)% for beef cattle, 10.5 (95% CI = 9.0–12.1)%, 16.7 (95% CI = 14.9–18.6)% and 14.0 (95% CI = 12.4–15.8)% for sheep and 6.6 (95% CI = 5.3–8.2)%, 15.5 (95% CI = 13.5–17.7)% and 3.6 (95% CI = 2.7–4.8)% for deer, respectively. Herd/flock-level seroprevalence for Ballum was 86.6, 52.4 and 39.0% for sheep, 85.2, 52.7 and 33.3% for beef cattle and 50.8, 27.9 and 21.3% for deer at definitions ≥1, ≥2 and ≥3 seropositive animals per species, respectively. For Copenhageni, corresponding data were 95.1, 73.2 and 56.1% for sheep, 68.5, 48.2 and 29.6% for beef cattle and 73.8, 57.4 and 41.0% for deer, and for Tarassovi, 80.5, 59.7 and 45.1% for sheep, 83.3, 68.5 and 61.1% for beef cattle, and 42.6, 16.4 and 4.9% for deer. Seropositivity to all serovars was observed from all regions, with some differences in seroprevalence observed between species and regions, but not between islands. Combining with Hardjobovis and Pomona data, herd/flock-level seropositivity for all animal species and all five Leptospira serovars was 100% at definition ≥1 animal positive, and 97.5 and 96.3% for sheep flocks, 87.8 and 97.8% for beef cattle herds, and 89.3 and 75% for deer herds at ≥2 and ≥3 animals positive, respectively. Conclusions Seropositivity to serovars Ballum, Copenhageni and Tarassovi is common in sheep, beef cattle and deer New Zealand and most, or all farms have ≥1 livestock species seropositive to ≥1 serovar. Clinical relevance Serovars Ballum, Tarassovi and Copenhageni should be considered when clinical or subclinical signs of leptospirosis are observed in sheep, beef cattle or deer. Livestock sector workers are potentially at risk of exposure.