Waikato Dairy Farms Research Articles

Impact of delivering ‘green’ dairy products on farm in New Zealand

There has been an increasing demand for livestock products with credence attributes (CAs), such as environmental sustainability and high animal welfare standards. Although most livestock product CAs are strongly related to farm-level production processes, rarely have studies explored the issue from an on-farm perspective. Therefore, this paper aims to explore whether consumers' willingness-to-pay (WTP) a price premium could incentivise dairy farmers to deliver products with CAs in New Zealand. We first employed a meta-regression analysis to estimate WTP for CAs of dairy products, and then incorporated the WTP estimates into farm system models to estimate the economic and environmental (nitrogen and GHG losses) impacts for the farms. Data for the meta-regression models were sourced from a literature survey yielding 32 studies estimating WTP for CAs of dairy products. The results showed that price premium ranged from 5.3% to 47.5% for environmentally-friendly dairy products. Farm system (FARMAX), farm environmental (OVERSEER) and life cycle assessment (LCA) models were used to model the farm system changes required to deliver ‘green’ dairy by using data for the average Waikato dairy farm. The results showed that the economic and environmental outcomes varied over the predicted range in WTP as well as for different farm system scenarios. Findings of the study could help inform NZ farmers as to how to adjust their farm systems in response to market signals and thereby potentially gain a price premium.

Preliminary investigation into the feasibility of combining satellite and GPS data to identify pasture growth and grazing

Regular estimation of pasture availability is a time-consuming on-farm task, but one that is vital for good grazing management. The ability to automate this task is, therefore, highly valuable. Combining satellite sensing of pasture mass with global positioning for herd location provides raw data that can potentially be used to automatically estimate pasture mass, pasture growth and pasture grazing events across a farm. The feasibility of automatically obtaining and processing this information was demonstrated on a Waikato dairy farm from 22 October 2018 to 21 February 2019 (123 days), with 13 global positioning collars recording the location of grazing mobs 16 times per hour on average, in a dairy herd of initially 380 animals. Satellite sensing of pasture cover over the same period was only possible on 16 days during this period, with November being particularly cloudy, resulting in fewer pasture cover estimates. A non-linear regression model was constructed with parameters representing initial pasture cover, average pasture growth rate through time, pasture growth differences between paddocks, pasture disappearance rate relative to the density of cow GPS samples, and an ungrazeable residual. A Bayesian approach was used to infer the model parameters from the satellite-measured pasture cover data. This allowed interpolation of pasture mass through the whole period with an RMSE of 225 kgDM/ha, as well as identifying growth rate differences between paddocks, which may provide a useful basis for improved pasture management. Rough estimates of cow average daily pasture disappearance were also made, which peaked at 20 kgDM/d in November, falling to 5 kgDM/d by February. This pilot study demonstrated the feasibility of combining satellite pasture cover data with herd location data from a small number of GPS collars to infer pasture growth rates in individual paddocks through time.

Variability in measurement of Pithomyces chartarum spore counts

AIMSTo examine the agreement between spore counts of Pithomyces chartarum measured in a single aliquot of wash water with counts from multiple aliquots from the same 60 g pasture sample, and between spore counts measured in an individual 60 g pasture sample with counts from three 60 g pasture samples selected from the same 200 g paddock sample.MATERIALS AND METHODSFour Waikato dairy farms were visited once weekly from early January to late May 2013. One paddock, with 40 sampling sites, was selected per farm. At each visit, ∼200 g of pasture was collected per site. Spore counting was undertaken using a standard method, except that three separate 60 g pasture samples per 200 g paddock sample was counted; and for each 60 g pasture sample, spores were counted in 10 aliquots of wash water. The relationship between the results of a single aliquot and 6–10 aliquots of wash water from the same 60 g grass sample were assessed by calculating 95% prediction intervals. Limits of agreement analysis was used to assess the agreement between counts from one, two or three aliquots per 60 g pasture sample compared with 10 aliquots, and between counts from one and three 60 g pasture samples from the same 200 g paddock sample.RESULTSComparing spore counts from individual aliquots with multiple aliquots resulted in large prediction intervals and 95% limits of agreement, which increased with increasing spore count. For an individual aliquot count of 2 spores, the 95% prediction interval for the count from 10 aliquots was 3–49 spores, and for an individual count of 10 spores the 95% prediction interval was 28–222 spores. Increasing the number of aliquots counted improved agreement. For a total count of 10 spores measured in 10 aliquots, the 95% limits of agreement, based on a single aliquot, were 2–50 spores, and for three aliquots were 5–20 spores. The agreement in spore counts measured in one compared with three 60 g pasture samples was moderate and also decreased with increasing spore count; the 95% limits of agreement were 4–14.5 for a mean spore count of 10.CONCLUSIONS AND CLINICAL RELEVANCEMeasuring the spore counts of three aliquots of wash water per 60 g grass sample improved repeatability, and should be used as the standard technique, particularly when determining whether to start or finish facial eczema control programmes.

Farm level survey of spore-forming bacteria on four dairy farms in the Waikato region of New Zealand.

The aim of our study was to determine the occurrence and diversity of economically important spore‐forming bacteria in New Zealand dairy farm systems. Farm dairy effluent (FDE) collected from Waikato dairy farms were tested for the presence of spore‐forming bacteria, using a new culture‐based methodology followed by genomic analysis. An enrichment step in which samples were inoculated in cooked meat glucose starch broth under anaerobic conditions, aided in the differential isolation of Bacillus and Clostridium species. Furthermore, the use of molecular methods such as ERIC genotyping, 16S rRNA gene sequence analysis identified different spore‐forming bacteria present in FDE. C. sporogenes signature PCR gave further information on the phylogenetic relationship of the different Clostridium spp. isolated in this study. In total 19 Bacillus spp., 5 Paenibacillus spp. and 17 Clostridium spp. were isolated from farm dairy effluent. Sequence types similar to economically important food spoilage bacteria viz: C. butyricum, C. sporogenes and members of the Paenibacillus Genus were isolated from all four farms, whereas, sequence types similar to potential toxigenic, B. cereus, C. perfringens, C. butyricum, and C. botulinum were found on at least three of the farms. Sampling of farm dairy effluent provides a good indicator of farm level prevalence of bacterial load as it is used to irrigate dairy pasture in New Zealand. This study highlights the presence of various spore‐forming bacteria in dairy waste water and indicates the implementation of good hygienic farm practices and dairy waste effluent management.

Pasture renewal on Bay of Plenty and Waikato dairy farms: impacts on pasture performance post-establishment

To determine the impact of pasture renewal on dairy pasture performance, a total of 24 renewed and unrenewed pastures were monitored in Bay of Plenty and Waikato for 5 years. Renewed pastures produced an additional 1.5, 1.8 and 1.9 t dry matter (DM) ha−1 in the first, second and third years of monitoring, respectively, compared with unrenewed pastures. There was a greater contribution of clover, sown grasses and unsown grasses and a smaller contribution of broadleaf weeds in renewed than unrenewed pastures in some years (% of total DM). The sown grass DM content (kg DM ha−1), perennial ryegrass tiller densities and endophyte infection frequencies were similar in renewed and unrenewed pastures. The abundance of invertebrate pests and total nematodes was lower in renewed than unrenewed pastures in some years. The greater clover content, fewer weeds and fewer insect pests, contributed to the greater herbage production of renewed pastures.

Multiple Criteria Decision Making Approach for Evaluating Management Options: A Case of New Zealand Dairy Farming

The continuous evolvement of dairy industry in countries like New Zealand, with increased dairy conversions and intensification, has resulted in remarkable economic development, though at the cost of environmental degradation. The increasing use of nitrogen fertilizers to sustain increasing number of cows has increased the risk of enhanced nitrate leaching and methane and nitrous oxide emissions. In this study, Compromise Programming (CP) and Weighted Goal Programming (WGP) have been applied to a Waikato dairy farm to reconcile economic goals with environmental and resources management goals. The models are based on Tier 2 methodology, developed specifically for New Zealand, for determining the energy requirements of cattle. The models are first applied with the current farm management practices to analyse the performance of the farm in meeting the two specific objectives of: (i) Attaining the production target of 1320kg MS ha -1 year -1 , Original Research Article Singh et al.; BJAST, 5(1): xxx-xxx, 2015; Article no.BJAST.2015.002 set by the farm management for maximizing profit and (ii) Keeping the nitrogen leaching limit to 26kg N ha -1 year -1 , as calculated by the agricultural management model OVERSEER nutrient budget. Model results show that with the existing management practices, it is not possible to meet the MS production and nitrogen leaching targets simultaneously. The production target of 1320kg MS ha -1 year -1 results in nitrogen leaching loss of 29kg N ha -1 year -1 whereas the nitrogen leaching target limits the production to 1195kg MS ha -1 year -1 . The results further shows that by keeping the number of cows calving in autumn within 150–200, and by putting an optimum area under the maize crop, it is possible to meet the twin objectives of minimizing the nitrogen leaching and maximizing the profit margins, though the production target has to be lowered significantly.

Value of chicory crops to pasture-based dairy farms in the Waikato region of New Zealand

SUMMARYChicory (Cichorium intybusL.) crops can increase milk production on New Zealand dairy farms through providing high-quality feed in late lactation. Non-linear optimization models of three Waikato dairy farms, differing in the degree to which imported supplement is used, were employed to evaluate chicory crops in this environment. At a baseline milk price of $NZ 7/kg milk solids, it was only profitable for chicory to be used on a farm where no imported supplement was fed. However, even then, only 0·04 of the farm area was planted and profit only increased by $NZ 30/ha (0·006 of baseline profit), relative to where it was not used. It was not optimal to plant any chicory on farms where imported feed was available, at the baseline milk price and cost of establishment considered here. This was evident because imported feed is more flexible than chicory for filling temporary feed gaps; also its use does not displace pasture production. Sensitivity analysis indicated that the unprofitability of chicory is robust to broad variation in calving date and the relative growth of chicory and pasture. Overall, results indicate that farmers are unlikely to receive adequate reward for the additional complexity arising from the utilization of chicory crops, especially when imported supplement provides more flexibility.

Improving the profitability of Waikato dairy farms: Insights from a whole-farm optimisation model

High milk volumes are encouraged in the New Zealand dairy industry to promote market access and utilise processing capacity. A detailed, nonlinear optimisation model of a pasture-based dairy farm in the Waikato region is used to: (1) assess the implications of maximising operating profit, (2) evaluate the cost of maintaining a focus on producing high milk volumes, and (3) characterise general management practices that maximise operating profit. Maximising milk volume within the simulated farm system reduces operating profit by 12%–23%, due to higher production costs. Nine principles for profitable management are developed, based on model output. These focus on the use of a medium to medium-high stocking rate (3–3.7 cows ha−1) to promote the growth, quality, utilisation, and intake of pasture. Imported concentrate is valuable to augment production in mid-lactation, but it is best to avoid feeding cows to potential given the high cost of supplement.

Economic feasibility of supplementary feeding on dairy farms in the Waikato region of New Zealand

Importation of supplement on New Zealand dairy farms allows relaxation of the constraints imposed on traditional grazing systems by seasonal pasture production and quality. The primary objective of this paper is to examine the relative profitability of Waikato dairy farms utilising different amounts of imported feed under price variation. An optimisation model of a Waikato dairy farm is used for this purpose. The case study indicates superior profitability associated with the use of a moderate level of imported supplement. A higher amount of imported feed allows lactation to be extended and promotes pasture utilisation through allowing the maintenance of higher stocking rates. However, these benefits decline past some optimal level of supplementation, beyond which pasture utilisation cannot be increased any further. Overall, this work highlights that although production can be increased by importing supplement, it is critical to consider the relative benefits and costs associated with the use of imported feed.

Pasture renewal on Bay of Plenty and Waikato dairy farms: impacts on pasture production and invertebrate populations post-establishment

The impact of renewal on pasture production was determined by monitoring renewed and unrenewed pastures on five farms in each of Bay of Plenty and Waikato for 3 years, excluding the year after sowing (establishment). Renewed pastures produced an additional 1.5 t dry matter (DM)/ha averaged over both regions in the second year after establishment and 1.9 t DM/ha in each of the third and fourth years. Renewed pastures also had greater clover DM content in spring and summer and lower broadleaf weed DM content in winter. Perennial ryegrass tiller densities were similar in renewed and unrenewed pastures in both regions. There were fewer white-fringed weevil, black beetle and total nematodes in renewed pastures on at least one of the sampling times. It was concluded that higher clover content, fewer weeds, and fewer insect pests contributed to greater DM production in renewed pastures. Keywords: Pasture renewal; dairy pastures; pasture persistence; DM production; regrassing

An assessment of the implications of timing and soil nitrogen dynamics during and after summer drought on Waikato Allophanic soils

Recommendations for farming when coming out of a drought are to apply fertiliser nitrogen (N), but when a drought breaks late in the season (i.e. mid to late autumn), the release of soil N has the potential to compound fertiliser N loads at a time when pasture N demand is low. Using the APSIM model, based on measurements made on a Waikato dairy farm and using data from the drought of 2007/8, an accumulation of 20 kg NO3-N/ha in the top 50 cm of soil post-drought was predicted, and therefore any fertiliser N applied during the drought would have added to the available N pool. Where a total of 70 kg N/ha fertiliser was applied during the drought, 35 kg NO3-N/ha was leached during the following winter. A glasshouse trial was subsequently run to observe N dynamics under controlled conditions. The pot trial confirmed that a substantial amount of available N was released (40-60 kg N/ha; 0-15 cm) upon rewetting after a "severe" drought, which may be sufficient to promote growth. The ability of pasture to grow and utilise soil/fertiliser N and the subsequent risk of N leaching will depend on how late in the season drought soils are returned to field capacity and when drainage commences. Keywords: pasture, nitrogen, nitrate leaching, nitrogen fertiliser, drought, ASPIM

The relationship between milk production and farm-gate nitrogen surplus for the Waikato region, New Zealand

As the scope and scale of New Zealand (NZ) dairy farming increases, farmers and the industry are being challenged by Government and the New Zealand public to address growing environmental concerns. Dairying has come under increasing scrutiny from local authorities tasked with sustainable resource management. Despite recent efforts of farmers and industry to improve resource use efficiency, there is increasing likelihood of further regulatory constraints on water use and nutrient management. This study uses available data on farm-gate nitrogen (N) surpluses and milk production from the Waikato, New Zealand's largest dairying region, together with a farm scale modeling exercise, to provide a perspective on the current situation compared to dairy farms in Europe. It also aims to provide relevant guidelines for N surpluses and efficiencies under NZ conditions. Waikato dairy farms compare favorably with farms in Europe in terms of N use efficiency expressed as L milk/kg farm-gate N surplus. Achievable and realistic good practice objectives for Waikato dairy farmers could be 15,000 L milk/ha (1200 kg milk fat plus protein/ha) with a farm-gate N surplus of 100 kg/ha giving an eco-efficiency (L milk/kg N surplus) of 150, and long-term average nitrate leaching losses of approximately 25-30 kg/ha/yr. This can be achieved by increasing the N conversion efficiency through lower replacement rates (16 versus 22%), lower stocked (< 3 cows/ha) high genetic merit cows (30 L milk/day at peak) milked for longer (277 versus 240 days), feeding effluent-irrigated, home-grown, low-protein supplements to cows on high-protein, grass-clover pastures to dilute N concentration in the diet, removing some of the urinary N from the paddocks during critical times by standing cows on a loafing pad for part of the day, and through lower N fertilizer rates (50-70 kg/ha/yr compared to the norm of 170-200 kg/ha/yr) and using a nitrification inhibitor and gibberellins to boost pasture growth and the former to reduce N leaching.

Escherichia coli and Campylobacter in two conventional Waikato dairy farm effluent ponds

Escherichia coli and Campylobacter were measured in the influent and effluent at two conventional dairy farm ponds (PS I and PS II) that discharged to surface water. Pond treatment reduced concentrations of both bacteria by about two orders of magnitude. From September to December both ponds discharged continuously at average rates of 0.235 L s−1from PS I and 0. 211 L s−1from PS I. Bacterial discharge, on a per cow per day basis, was 6.7×107 E. coli and 8.6×105 Campylobacter from PS I and 3.0×108 E. coli and 2.8×106 Campylobacter from PS II. Later in the season effluent discharge declined, fewer cows were milked but bacterial loads remained high at 1.2×107 E. coli and 1.7×104 Campylobacter cow−1 d−1. These findings demonstrate the unsatisfactory microbiological quality of pond effluent and that discharge to surface water is a poor option.

Predicting accurate paddock-average pasture cover in Waikato dairy farms using satellite images

Effective monitoring of pasture cover on a regular basis is essential if dairy farmers are to increase profitability by making better pasture management decisions. We present results of a two-year study on the use of satellite imagery to estimate pasture cover on dairy farms in the Waikato region. Data collection concentrated on the critical time for dairy farm pasture management between June and December. Two distinct relationships between the remotely-sensed normalised difference vegetation index (NDVI) and pasture cover were observed, with an inflexion point in the relationship at NDVI = 0.74. A two-part exponential model was fitted to the data, allowing the prediction error to be minimised both above and below the inflexion point. Model development showed that an algorithm based on NDVI and time-of-year accounted for approximately 80% of the variability in pasture cover measured within paddocks. The validation studies show that pasture cover was estimated with an error of prediction of approximately 10%, which equates to 260 kg DM/ha for a pasture cover range of 1500 to 3400 kg DM/ha. The accuracy demonstrated in this study has given the project's funders the confidence to explore a staged rollout of development, validation and commercial delivery, to make the technology available to all major dairy regions in New Zealand over the next five years. Keywords: Pasture cover, dairy, satellite imagery, rising plate meter, normalised difference vegetation index

Control of pollutants using stand-off pads containing different natural materials

Farmers are increasingly using management systems such as moving cows out of paddocks onto stand-off pads to protect wet soils from damage during winter. Studies were carried out to investigate nutrient and faecal bacterial retention or loss from stand-off pad materials. A preliminary laboratory study found that a range of natural materials, including crushed pine bark, wood chips, zeolite and soil can retain between 66% and 76% of applied cows' excreta nitrogen (N). Zeolite was found to be particularly good at reducing ammonia (NH3) volatilisation losses from the columns. A field-scale standoff pad study at a Waikato dairy farm, in the winter season of 2005, indicated that carbon (C)-rich materials including both bark and sawdust can be used as standoff pad materials with effective retention of N and faecal bacteria. Both bark and sawdust pads retained about 60% of deposited excreta N. Substantially more Escherichia coli were recovered in the drainage from the bark pad (total yield 3.1 x 1011 E. coli) than from the sawdust pad (total yield 7.5 x 109 E. coli) demonstrating that sawdust was more effective than bark in retaining these faecal bacteria. Keywords: stand-off pads, winter management, dairy, nitrogen, faecal bacteria, natural materials

Resource use efficiency and environmental emissions from an average Waikato dairy farm, and impacts of intensification using nitrogen fertiliser or maize silage

A life cycle assessment (LCA) approach was used to estimate whole-system (dairy farm + grazing and forage land) resource use and environmental emissions for an averag e Waikato dairy farm enterprise. Effects of increased production from 850 to 1020 kg milksolids/ha using more nitrogen (N) fertiliser (+200 kg N/ha/yr) or forage (+2 t DM/ha/yr maize and oats silage) were also assessed. Fertiliser N increased production and economic efficiency, but decreased environmental efficiency through a predicted increase in N leaching and greenhouse gas (GHG) emissions. In contrast, using forage increased the use of land but increased milksolids/ha and with no loss in environmental ef ficiency (per kg milksolids). A preliminary compar ison of the average Waikato farm system and an example Swedish dairy farm system showed small dif ferences in environmental efficiency (GHG or N leaching/m3 milk) but much higher (5-fold) energy efficiency on the Waikato farm. This is important to maintain, particularly as farms intensify, if "food-miles" (energy use in transpor ting produce to markets) become a component of our "ecolabel" for supplying produce to overseas markets. Keywords: dairy farm, ef ficiency, environment, intensification, maize, nitrogen, resource use

Experiences with evaluating two farming systems in a split herd comparison on a commercial Waikato dairy farm

An on-farm demonstration of the effects of a higher stocking rate (expressed as cows per hectare), supported by purchased maize silage, was conducted on a commercial Waikato dairy farm that was split into two farmlets. Milk from each farmlet was collected into separate vats. This paper reports on two seasons of comparison between: 1. A 57-ha farmlet with 185 Friesian cows stocked at 3.25 cows per ha, representing the farm's previous management (Control -LS) and; 2. A 51-ha farmlet with 185 Friesian cows stocked at 3.6 cows per ha, supported by the purchase of 430 kg DM per cow of maize silage (Treatment -HS) The comparison aimed to demonstrate that higher stocking rates, supported by purchased maize silage, would increase total pasture utilisation and increase profit per hectare. Milksolids production for the HS farmlet was 105 and 99 kg per ha higher than LS in years one and two with Economic Farm Surplus per ha increasing by $113-$375 per ha (depending on payout). The comparison highlighted the difficulty of determining stocking rate on a cows-per-ha basis for a farm with unknown pasture production. In effect, the comparison was between two herds stocked at a similar level relative to total feed supply, with both herds being limited by total feed supply. This study also demonstrated practical management issues involved for farmers who are adding purchased feed into their systems. Being a commercial dairy farm meant this split herd demonstration could not be subjected to strict scientific protocols, as the commercial objectives of the farmers had to be met. The limitations and advantages of this type of on-farm demonstration are discussed. Keywords: economic farm surplus, maize silage, milksolids production per ha, on-farm demonstration, split-herd comparison, stocking rate

Nutrient budgets - a key indicator of soil sustainability

Sustainable land management is now embedded in New Zealand law in the form of the Resource Management Act, 1991. Nutrient budgets and soil tests are seen as important tools for monitoring soil chemical sustainability. Nutrient budgets require that all inputs and outputs of nutrients from a farm are quantified. The aim is to ensure inputs and outputs are in balance thus producing a sustainable system. Recent experience suggests that using the study group (or Landcare group) approach is an effective way of introducing the nutrient budgeting approach to farmers. At the same time a computer software package ('Overseer') for assisting the calculations involved is being developed and tested. P nutrient budgets for two Waikato dairy farms suggest that surplus P is being produced. Such information provides a basis for future decisions on P fertiliser inputs to balance the P requirements for production against those for sustainable land management. Nutrient budgets can be aggregated to the regional and national level as required. By being able to calculate nutrient budgets in this way, New Zealand will be in a good position to _ demonstrate a commitment.to.nutrient.management~ thus ensuring continued and perhaps enhanced market access for our agricultural products. Keywords: dairying, nutrient budgets, study groups, sustainable land management

Beef production from the dairy herd

Abstract Calves born to Friesian dams and sired by Friesian (F × F), Hereford (H × F), Simmental (S × F), Angus (A × F), Limousin (L × F), South Devon (SD × F), Blonde d'Aquitaine (BA × F), Red Devon (RD × F), and Charolais (C × F) sires were born and reared on 21, 18, 16, and 19 Waikato dairy farms in the spring seasons of 1973–76 respectively. Weaned calves were transferred to grazing farms at approximately 4 months of age. The “environment” of the dairy farm was an important source of variation in growth rate from birth until transfer. Some of this variation was associated with method of rearing. Over all years live-weight gain from birth to 12 weeks of age was 18.7 kg greater on farms with suckled calves than on those farms using artificial rearing techniques. Compared with the F × F in each year, CxF, L × F, SD × F, S × F, and BA × F calves were heavier and A × F, RD × F, and H × F were lighter at transfer in the descending order given. These differences reflected birth weight to a greater extent than post-natal growth rates. Individual sires-withinbreeds significantly affected age-corrected transfer weight. Heritability estimates were generally higher for age-corrected live weights than for growth rates. Steer calves grew faster than heifers, but age of dam did not affect post-natal growth.