1. Facilitating Market Access Category

1.1 FMA 120

Programme Title:

Revision of the genus Rhizoglyphus in New Zealand and Australia

Programme Leader:

Zhi-Qiang Zhang

Institution:

Landcare Research CRI

Summary

To provide a revised taxonomy of Rhizoglyphus species in New Zealand and Australia and to prepare user-friendly identification keys to species. The keys will be based on the morphological characters of the adults (both males and females).

Background

A key is required that allows identification of Rhizoglyphus mites in New Zealand to facilitate requests for rapid quarantine decisions from trading partners.

Approach & Outcomes

Existing slide-mounted specimens in NZAC, MAF NPPRL in Lincoln and Lynfield, and other available material, were collated, assessed and examined by light microscopy, and diagnostic features discriminating genera and species were identified and illustrated by line drawings. All species were fully described with illustrations. Distributional data and host plants were listed based on published records but mostly from data accompanying the specimens.

More than 1840 Rhizoglyphus mite specimens of different stages mounted in over 600 slides mainly from Australasia and Oceania were examined. A revision was completed not only for Australia and New Zealand, but also for other countries in the Oceania. A total of 210 figure plates were prepared and 14,550 morphological data were taken. Eleven species known from Australasia and Oceania were described: R. caladii Manson (New Guinea, India / Nepal, Taiwan), R. columbianus Oudemans (Australia, Columbia, Tahiti Island), R. echinopus (Fumouze & Robin) (Worldwide), R. howensis Manson (Australia), R. minutus Manson (Fiji, New Zealand, Niue Island, Samoa, Tonga), R. sp. O nov. (New Zealand), R. ranunculi Manson (New Zealand), R. robini Claparède (Worldwide), R. setosus Manson (Australia, Cook Island, Cuba, Fiji, Hong Kong, Japan, New Guinea, Pacific Islands, Samoa, Singapore, Taiwan, Thailand, Tonga, U.S.A), R. singularis Manson (Fiji, India, Indonesia, Taiwan) and R. sp. T nov. (Tokelau Island). Lists of hosts are also provided. Rhizoglyphus longispinosus Ho & Chen, 2001 is considered as a junior synonymy of R. caladii Manson, 1972; R. tacitri Manson, 1972 a junior synonymy of R. columbianus Oudemans, 1924; and R. tsutienensis Ho & Chen, 2000 a junior synonym of R. singularis Manson, 1972.

1.2 FMA 121

Programme Title:

Effect of level of shepherding on ewe and lamb death rate between scanning and weaning.

Programme Leader:

Greg Lambert

Institution:

AgResearch CRI

Summary

To investigate the relationship between shepherding practice and ewe and lamb welfare and survival on New Zealand sheep farms.

Background

New Zealand depends strongly on continued access to overseas markets (UK and Europe) for lamb products, and as such is subject to the whims of consumers. With New Zealand's relatively `hands-off' approach to lambing compared to those market countries, New Zealand's lambing practices could be misconstrued as poor animal welfare and be used to restrict market entry.

Objective information on shepherding practices on New Zealand farms is needed to allay any negative connotations the `easy-care' label may convey, in order to maintain access to overseas markets.

Approach & Outcomes

A survey of a cross-section of over 400 New Zealand sheep farms was undertaken to quantify shepherding practice broadly and determine the extent to which this may influence ewe and lamb mortality.

Ewe scanning data were used to calculate the % potential lambing and combined with tailing data to produce % potential lamb loss, which were then analysed against frequency of shepherding and other factors using linear regression and covariance analysis.

Outcomes:

Elements of the 'easy-care' lambing flocks developed for hill country conditions are now used by 80% of New Zealand sheep farmers and have encouraged a move towards lambing systems with reduced intervention. Shepherding once a day is the most prevalent system, but ranges from no intervention (chiefly extensive hill and high country) to more than twice a day (intensive lowland).

Statistical analysis showed that ewe and lamb losses were not affected by frequency of shepherding, but were more related to litter size and physiographic factors such as altitude, topography and flock size, which are largely outside the control of the farmer.

The success of this study depended on good data from those farmers scanning their ewes. Of the 434 farms surveyed, 58% scanned their ewes, but unfortunately only 107 (25%) could provide scanning results, a minimal dataset for the loss analysis and a disappointing outcome. A larger targeted dataset is desirable to elucidate these relationships more fully.

1.3 FMA 122

Programme Title:

Dairy Calf Welfare

Programme Leader:

David Mellor

Institution:

Massey University

Summary

Dairy calves are removed from their mother during the first day of life and then reared artificially using a variety of calf feeders and management systems. In New Zealand calves are usually picked-up in the late morning or early afternoon and then placed in a rearing shed. They may be fed in the hours after pick-up or not until the next morning. Initially calves are fed individually but they are usually moved onto a `calfeteria', a multiple calf feeder, within the first few days of life. On the calfeteria there will be some competition between calves and the faster feeders will ingest more milk than the slower feeders. This may be a problem with young calves that are learning to feed off an artificial teat or in older calves feeding on large calfeterias with many teats.

Background

This study investigated the sucking behaviour of calves during the first 4 days of life and looks at how this behaviour develops in individually fed calves. It also reports on the milk intake of calves 4 to 11 weeks of age when fed on either a gravity-fed calfeteria or one involving sucking milk up through a pipe.

The majority of newborn calves became efficient suckers from gravity fed individual bottles within 24 hours of pick-up and 95% drank the full 2 litres of colostrum offered on day 2. On day 4 virtually all (99%) drank the 2 litres offered. A small number of calves that had not ingested colostrum from their mothers and drank less than 500 mls of the 2 litres of colostrums offered after pick-up were especially at risk of not drinking 2 litres on the following days. In general calves that had not drunk colostrum from their mothers before pick-up were more likely to drink all 2 liters offered after pick-up but there was little difference between the calves on day 4. Calves that did not drink all 2 litres on day 1 were not disadvantaged in comparison to those that did so in that they were equally likely to be drinking 2 litres on day 4. However in this study all the calves were fed individually and this allowed those calves that are slow feeders to get all 2 litres. In fact some calves were found to suck 10% slower than others and if they were competing from a common calfeteria there could be ongoing and significant differences in intake and resultant growth rate and survival for the slow feeders.

The intake of milk by the older calves was similar on both feeder types and there were few consistently slow or fast drinkers. This suggests that there are unlikely to be many disadvantaged calves on either calfeteria type. It was obvious that calves on the pipe type calfeteria were more likely to remain for longer on the teat during the later weeks when they were being fed 5 litres at one feeding than calves on the gravity fed calfeteria. The number of calves on these calfeterias was low (<30) and it is likely that more obvious problems could develop on feeders of this type with 80 teats. It was theorised that the pipe feeder might have more of an effect than the gravity feeder but this was not shown by the data.

Approach & Outcomes

In conclusion:

  1. Newborn calves rapidly learn to drink from an artificial teat and bottle.
  2. By day 2 of life the majority of calves are drinking all 2 litres of milk but some are up to 10% slower at drinking than others. This might have an impact if they are fed from a communal feeder.

There is little difference in the milk intake of calves feeding on gravity or pipe fed calfeterias between 4 and 11 weeks of age.

1.4 FMA 123

Programme Title:

Shade for Sheep

Programme Leader:

Jim Webster / Jo Pollard

Institution:

AgResearch CRI

Summary

To define the behavioural and physiological needs of sheep for shade in hot, dry and hot, humid environments.

Background

Casual observations indicate that in many regions of New Zealand sheep have high requirements for shade as they seek it readily on sunny days during much of the year. However, quantitative studies of responses of sheep to shade have not been carried out in New Zealand. The requirement for shade is likely to be highest in hot, humid conditions where respiratory cooling is less effective, but they may also experience an excessive heat load in dry areas where levels of solar radiation are high. This project aims to define the needs of sheep for shade in these two contrasting environments by assessing its effects on behaviour and physiological indicators of heat stress.

Approach & Outcomes

Part A of the study was carried out in a hot, dry environment (at Poolburn, in Central Otago, in February 2003). Twenty-four Romney crossbred ewes, divided into two groups of 12, were observed on a commercial farm during 10 consecutive fine days. The groups were studied in adjacent paddocks, one with shade provided by willow trees and one with no shade, for five days, then the groups were swapped between shaded and non-shaded paddocks.

Records were made of activities during daylight hours, respiration rate in the early morning, early afternoon and during handling and intra-vaginal temperature and weather conditions every 10 minutes during the 10 days. Part B of the study will be carried out using identical methods in a hot, humid environment (Hamilton, in summer 2003/2004).

Outcomes: Unfavourable weather conditions during an attempt at completing Part B (at the hot, humid site, in February 2002) caused this second part of the data collection to be postponed.

In Part A, activities differed between shaded and non-shaded groups, with non-shaded sheep resting more during periods of high air temperature. Sheep provided with shade used it in 43% of observations overall and in 84% of observations in which the sheep were resting.

A diurnal cycle in intra-vaginal temperatures was observed, with minimum values in the early morning and maximum temperatures in the afternoon. Intra-vaginal temperatures were higher in the non-shaded sheep during the full 24 hour period (mean 39.21oC) compared to the shaded sheep (mean 39.11, SED 0.032oC, P<0.01), and during daylight hours (respective means 39.18 and 39.05, SED 0.030oC, P<0.001).

Respiration rates were 35-42 breaths per minute in the early morning and did not differ between shaded and non-shaded sheep. Respiration rates in the early afternoon were higher in the non-shaded sheep than the shaded sheep (121 compared to 93, SED 7.3 breaths/min, P<0.001). No effect of the shade treatment was seen on respiration rates during handling.

The substantial use of shade and reduction in intra-vaginal temperature and respiration rate in the sheep with shade indicated that it was of significant benefit to the sheep in the study. Results from Part A were discussed in the light of previous studies on responses of sheep to hot conditions and shade. The results and their implications for animal welfare will be considered and discussed further when Part B has been carried out.

Publications

Pollard, J.C., Hogan, N., 2003. Behavioural and physiological requirements of sheep for shade: Part A. Confidential report to MafPolicy. 22pp.

1.5 FMA 124

Programme Title:

Neonatal mortality in Wiltshire, Dorper and Damara sheep and their crosses with woolled breeds.

Programme Leader:

David Scobie

Institution:

AgResearch CRI

Summary

Gather data on neonatal mortality of hair sheep (Wiltshire, Dorper and Damara) and their crosses with woolled breeds, relative to woolled breeds throughout various regions in New Zealand.

Background

As the numbers of shedding and hair sheep increase in New Zealand, public awareness and concern about welfare issues will also increase. Uncertainty surrounds the ability of lambs from shedding and hair breeds to withstand wet cold conditions following their birth.

Approach & Outcomes

Thirty nine farmers, breeding pure and/or crossbred Dorper, Damara or Wiltshire lambs were approached regarding involvement with the project. The information requested for each breed type was the number of:

  • number of ewes lambed;
  • lambs born;
  • neonatal lamb deaths;
  • lambs tailed; and
  • lambs weaned.

Nineteen farmers, from 7 regions, were able to provide information within the timeframe of the project for lambs born during the 2002 lambing. Eleven of the 19 properties were able to provide information for two or three breed types (hair, wool, hair x wool) run on the same property. Eight properties were only able to provide information for hair or hair x wool lambs. Comparative information for wool breeds was obtained from neighbouring properties. Lamb mortality (%) was calculated as the proportion of lamb deaths between birth and weaning.

Outcomes:

The percent of lamb deaths between birth and weaning were similar between hair, wool or hair x wool lambs. The tendency towards lower lamb mortality in hair x wool lambs is probably an effect of heterosis.

Fibre type

no. lambs

% mortality

hair

893

16.3

wool

22,161

15.5

hair x wool

11,337

12.4

lsd 0.05

  

10.2

The similarity in lamb mortality between breed types precluded closer examination of differences in mortality rates within the hair (Dorper versus Wiltshire) or hair x wool (hair x long wool versus hair x short wool) breed types. Similarly, cause of death, type of fleece cover and quantity of fleece cover at birth do not warrant further investigation.

The proportion of lamb deaths throughout the regions studied ranged from 5.5% in Hawkes Bay/Wairarapa to 19.1% in North Otago. It is important to note that the mortality figures for breed types and regions align with the long-running national average of 18%, and fall within the normal range of 5 - 25% (Meyer and Clarke, 1978).

Summary:

Data on mortality rates of lambs from hair and hair x wool breeds was collected to address uncertainty surrounding the ability of these lambs to withstand wet, cold conditions following their birth. Information provided by 19 farmers, from 7 regions throughout New Zealand, showed that lamb deaths between birth and weaning did not differ between hair, wool or hair x wool breeds.

Publications

No publications to date. A copy of the final report will be forwarded to all participants and will be available to members of the Sheep Breeders Association. A general media release is planned, following consultation with MAF. Results from this study may be incorporated in a larger study of the performance of hair breeds in New Zealand, and published in the proceedings of a science conference.

1.6 FMA 125

Programme Title:

Alleviation of dehorning distress in calves

Programme Leader:

Professor David Mellor

Institution:

Massey University

Summary

Current animal welfare guidelines suggest that lambs should be castrated at a young age in order to minimise the pain associated with this husbandry procedure. The aim of this study was to use the electroencephalogram (EEG) to ascertain whether the response of the cerebral cortex, to the noxious stimulus of castration, varied with age. Two groups of East Friesian lambs were selected according to age. The age of the younger group (n = 21) was 12 ± 2 (mean ± SD) days and the older group (n = 20) was 29 ± 1 days. Lambs were anaesthetised by inhalation of halothane in oxygen and instrumented to record the EEG and the electrocardiogram (ECG). Once a stable plane of anaesthesia had been achieved (FIhal = 1.5%), data collection commenced and the lambs were castrated 15 minutes later using rubber rings. Median (F50) and spectral edge (F95) frequencies and total power (ptot) were derived from the EEG data. Following castration there was an increase in F50 in the young lambs (P = 0.002) and an increase in ptot in the older lambs (P = 0.05). No other EEG variables demonstrated significant changes following castration. Both younger and older lambs exhibited a transient bradycardia (P = 0.001, P = 0.01, respectively). The increase in ptot in the older lambs suggests that anaesthesia was not as deep in these animals as in the younger group. Despite this, the animals in the younger group demonstrated an increase in F50 consistent with a cortical response to the noxious stimulus of castration. These data suggest that two-week-old lambs undergo a greater cortical response to noxious stimulation than do four-week-old lambs.

Background

Abstract

Current animal welfare guidelines suggest that lambs should be castrated at a young age in order to minimise the pain associated with this husbandry procedure. The aim of this study was to use the electroencephalogram (EEG) to ascertain whether the response of the cerebral cortex, to the noxious stimulus of castration, varied with age. Two groups of East Friesian lambs were selected according to age. The age of the younger group (n = 21) was 12 ± 2 (mean ± SD) days and the older group (n = 20) was 29 ± 1 days. Lambs were anaesthetised by inhalation of halothane in oxygen and instrumented to record the EEG and the electrocardiogram (ECG). Once a stable plane of anaesthesia had been achieved (FIhal = 1.5%), data collection commenced and the lambs were castrated 15 minutes later using rubber rings. Median (F50) and spectral edge (F95) frequencies and total power (ptot) were derived from the EEG data. Following castration there was an increase in F50 in the young lambs (P = 0.002) and an increase in ptot in the older lambs (P = 0.05). No other EEG variables demonstrated significant changes following castration. Both younger and older lambs exhibited a transient bradycardia (P = 0.001, P = 0.01, respectively). The increase in ptot in the older lambs suggests that anaesthesia was not as deep in these animals as in the younger group. Despite this, the animals in the younger group demonstrated an increase in F50 consistent with a cortical response to the noxious stimulus of castration. These data suggest that two-week-old lambs undergo a greater cortical response to noxious stimulation than do four-week-old lambs.

Key words: Electroencephalogram, nociception, pain, lambs, castration.

Discussion

Pain has been defined as an unpleasant sensory and emotional experience associated with actual or potential tissue damage (IASP 1994). The sensory processes by which pain is detected are termed nociception. Sentience and consciousness are requisite to the experience of pain. In the current study the cortical responses of lightly anaesthetized lambs to noxious stimuli were investigated. Anaesthetized animals were used to avoid contamination of the EEG arising from body movements, to avoid age constraints arising from the use of chronically implanted electrodes, and to avoid unnecessary suffering imposed by the experimental procedure. Whilst anaesthetized animals cannot experience pain per se they can have responses to noxious stimuli (Bonica, 1990) that correspond to pain in the conscious animal. Whilst these responses will be blunted by the anaesthetic (Bonica, 1990), the use of this model for the investigation of nociception has been validated (Murrell et al., 2003).

The EEG has been extensively used to monitor the depth of anaesthesia (Schwilden, 1989). hanges in the concentration of an inhaled agent result in predictable changes in the power spectrum of the EEG. Changes in end tidal halothane concentration were correlated with changes in F95 (Johnson et al., 1994, Johnson and Taylor 1998). In the current study, end tidal halothane concentration was not monitored, however, 45 minutes were allowed for steady state (FIhal = 1.5%) to be achieved, and there were no significant changes in the baseline of the F95 or ptot over the recording period. Thus it is not likely that alterations in anaesthesia produced the EEG changes. Furthermore, significant changes in the EEG variables occurred rapidly at the time of castration and so were not likely to be due to fluctuations in anaesthesia.

The EEG is an indicator of cerebral activity (Adrian and Matthews, 1934). Therefore, any extrinsic factors which affect cerebral blood flow, such as mean arterial blood pressure, arterial carbon dioxide pressure (PaCO2), arterial oxygen pressure (PaO2) and body temperature, can affect the EEG (Paulson and Sharbrough, 1974). In the current study, these were not monitored, however, there were no clinical signs of respiratory or cardiovascular perturbations. Furthermore, in a similar experimental protocol, the EEG appeared robust to changes in PaCO2, PaO2 and body temperature over a normal physiologic range (Murrell et al., 1998, 2003). In addition, the stability of the baseline heart rate data suggests that there were no progressive changes due to anaesthesia. Whilst it is possible that there were minor fluctuations in these variables they are unlikely to have influenced the EEG data.

Both ptot and F95 of the EEG respond to alterations in level of anaesthesia. Studies in man have demonstrated that ptot responds preferentially to changes in the adequacy of anaesthesia (Long et al., 1989; Drummond et al., 1989; Trast and Kalkman, 1995). Other studies, in the horse, have shown that F95 responds preferentially to changes in the dose of anaesthetic agent (Johnson and Taylor, 1998). Similarly, F95 has been shown to be a sensitive indicator of recovery from anaesthesia (Antognini et al., 2000). In the current study, the change in ptot in the older lambs after castration suggests that these animals were less adequately anaesthetized, that is, they were aroused by the procedure. It is well recognized that noxious stimulation arouses the central nervous system (Bonica, 1990). The absence of changes in F95 is consistent with previous work investigating the noxiousness of castration in horses utilising a similar model of minimal halothane anaesthesia (Murrell et al., 2003).

The increase in F50 following the noxious stimulus of castration in younger lambs (Fig 2; Table 1) is consistent with previous studies (Murrell et al., 2003; Jongman et al., 2000) and supports the proposal that F50 responds preferentially to noxious stimuli (Murrell et al., 2003). Whilst in older lambs the increase in F50 after castration was close to, but did not reach, statistical significance (P = 0.066), we consider that this response represents a trend towards significance and represents a real change of smaller magnitude than that in the younger lambs.

The increase in ptot in the older lambs demonstrates that these animals were more aroused by castration than younger lambs. Despite this, lambs in the younger group demonstrated a greater increase in F50 which is consistent with a cortical response to noxious stimulation (Murrell et al., 2003). Taken together, these data suggest that younger animals undergo a greater cortical response to noxious stimulation than do their older counterparts. It follows that in the field, younger lambs would experience more pain following castration than would older lambs.

Noxious stimuli elicit activity in the sympathetic nervous system (Bonica, 1990). In the current study, both younger and older lambs exhibited a small but significant bradycardia, which returned to pre-treatment values by about four minutes after castration. In contrast, castration and tailing in 9 week old conscious lambs elicited significant tachycardia and hypertension from 20 mins until after 4 hours (Peers et al., 2002). These apparently different cardiac responses to castration may be artifactual due to the different sampling timecourse in the two studies. Alternatively they may be due to differences in the responses of anaesthetized compared to conscious animals.

The timecourse of the cortisol and behaviour responses to rubber-ring castration are well established and return to pre-treatment levels by about three hours (e.g. Mellor and Stafford, 2000; Lester et al., 1996). The noxiousness of rubber-ring castration is largely due to initial stimulation of mechanoreceptors followed by ischaemic pain, arising from anoxia which eventually disables nociceptor activity (Cottrell and Molony, 1995). In anaesthetized lambs, this ischaemic-induced nociceptor activity continues for more than 90 minutes (Cottrell and Molony, 1995). Recently, the pain of castration has been assessed using other indices including catecholamines (Mellor et al., 2002), cardiovascular, metabolic and electrolyte changes (Peers et al., 2002) and spermatic nerve activity (Cottrell and Molony, 1995). The timecourses reported for these other indices lie outside the scope of this study. It is interesting to note that the time constant of the initial decay (90 s) in Spermatic nerve activity found by Cottrell and Molony (1995) is similar to the timecourse of the EEG response reported here.

It is not possible to determine, from these data, whether the different EEG responses to noxious stimulation with age were due to differences in the perception of pain per se, to differences in the degree of noxious input or to differences of processing in the peripheral and central nervous system. For example, differences in the degree of noxious input may arise from variation in the size and type of tissue involved, and differences in the processing of noxious stimulation may arise from maturational changes involving nervous tissue thresholds or connections. Other studies, which have correlated EEG changes with the subjective perception of pain (Chen et al. 1989), would suggest that the former is the case. It was surprising to find differences of such magnitude in lambs that were only two weeks apart in age. These data raise questions about the extent to which pain is perceived in very young animals.

From a husbandry perspective, the fact that younger animals may feel more pain is more important than the reason for this disparity in pain perception with age, castration being a routine husbandry practice. The recommendations to perform necessary husbandry tissue removals on younger animals were based on pragmatics, which included ease of handling, performance consequences and age-benefit constraints. These pragmatic matters have merit but should be balanced with welfare considerations especially in light of possible sensitive periods in neonatal life which may lay the foundation for future experiences and responses (Grunau, 2000).

In conclusion, the increase in ptot following castration in the older lambs suggests that these animals were more aroused than those in the younger group. Despite this, the lambs in the younger group demonstrated an increase in F50 consistent with a cortical response to the noxious stimulus of castration. These data demonstrate that two-week-old lambs undergo a greater cortical response to noxious stimulation than do four-week-old lambs and suggest that younger lambs experience more pain following castration than older lambs. This questions the validity of current welfare recommendations concerning the castration of lambs without provision of analgesia and has implications for all noxious husbandry procedures that are conducted on young animals. Age-related variation in the response to noxious stimulation needs further characterization in order to be able to make welfare recommendations based on experimental data.

1.7 FMA 126

Programme Title:

Welfare guidelines for low-chemical pastoral farming

Programme Leader:

Alex MacKay

Institution:

AgResearch CRI

Summary

Develop animal welfare criteria for determining the welfare of young stock in low-chemical pastoral sheep and beef farming systems, document the current approach (i.e. Decision rules) used in low-chemical farming systems for identifying and treating at-risk animals and develop a set of decision rules for inclusion in the on-farm animal management plan, in low-chemical production specifications (e.g. NZ Organic Standard). Decision rules will cover both the conversion period and following full certification, and be used in the relevant animal welfare codes.

Background

A recent review (Stafford and Mellor, 2002) found little data to either support or dispel the perception that low-chemical (natural/organic) pastoral sheep and beef farming systems compromise animal welfare. Interest in low-chemical farming systems is increasing. MAF, with its statutory responsibilities under the Animal Welfare Act 1999 (repeals the Animals Protection Act 1960), has questioned whether the existing codes of recommendations and minimum standards for the welfare of farmed animals (developed by the Animal Welfare Advisory Committee, AWAC) adequately address animal production systems where chemical controls are not used routinely to manage animal health and disease challenges.

Reference

K.J. Stafford and D.J. Mellor, 2002. Organic Livestock Farming and Animal Welfare Conference on Animal Welfare and Behaviour. From Science to Solution. N Hamilton 27-28th June 2002.

Approach & Outcomes

The project was tackled in a series of studies:

  • An assessment was made of the health and welfare of young stock (<1 year of age) in low-chemical pastoral sheep and beef farming systems.
  • To undertake this task, criteria were developed for assessing the welfare of young stock in low-chemical pastoral sheep and beef farming systems.
  • On each case farm, the effectiveness of the current approach (decision rules) used by the farmer to identify and treat at-risk animals to a range of disease challenges was documented.
  • The decision rules were compared with the concept developed to identify at-risk livestock in a conversion planning project and methods used to identify and manage at-risk stock in an experimental livestock production system.
  • A report was prepared with recommendations on possible changes to existing codes of recommendations and minimum standards for the welfare of farmed animals, to address animal production systems where chemical controls are not used routinely to manage animal health and disease challenges.

Outcomes

  • The project provides the first quantitative data on the welfare of animals on low-chemical properties in New Zealand. In the five domains of potential animal welfare compromise, namely nutrition, environment, health, behaviour and mental state, the two most likely to be affected by low-chemical farm management are those related to the treatment and prevention of disease and the supply of adequate food.
  • An animal welfare checklist was developed, as no suitable package was available for assessing animal welfare in a systematic and quantitative manner.
  • Existing codes of recommendations and minimum standards for the welfare of farmed animals were found to address animal production systems where chemical controls are not used routinely to manage animal health and disease challenges.
  • Inclusion of decision rules in low-chemical production specification would reduce the risk of a disease and welfare breakdown occurring in low-chemical systems, by introducing more systematic and objective components into the routine monitoring of at-risk livestock.

The final report recommends:

  • Discuss the findings of the study with the agencies holding and undertaking certification of low-chemical production systems and encourage each to consider including decision rules in their production specifications.
  • Investigate the benefits of a decision rule based approach to the wider pastoral industry.
  • Continue the development of a robust "on-farm animal welfare checklist" for assessing the welfare status of animals during conversion to a low-chemical system. The checklist may also be useful in assessing the effectiveness of on-farm assurance schemes, highlighting the gaps in current farm quality assurance schemes, and providing data on implications of changed animal management.

Summary

Interest in low-chemical systems is on the increase. This has raised questions on the adequacy of existing codes of recommendations and minimum standards for the welfare of farmed animals in these production systems, where chemical controls are not used routinely to manage animal health and disease challenges. This report summaries the findings of a series of studies, including an assessment of the health and welfare of young stock (<1 year of age) on four low-chemical pastoral sheep and beef farms was part of the study.

The report provides the first quantitative data on the welfare of animals on low-chemical properties in New Zealand. An animal welfare checklist was developed as part of the project, as no suitable package was available for assessing animal welfare in a systematic and quantitative manner.

Existing codes of recommendations and minimum standards for the welfare of farmed animals were found to address animal production systems where chemical controls are not used routinely to manage animal health and disease challenges. Inclusion of decision rules in low-chemical production specification would reduce the risk of a disease and welfare breakdown occurring in low-chemical systems, by introducing more systematic and objective components into the routine monitoring of at-risk livestock.

1.8 FMA 127

Programme Title:

Monitoring truck microclimates

Programme Leader:

Clive Marsh

Institution:

WRONZ (New Canesis Ltd)

Summary

A Stock Truck Climate Monitoring system has been specified, designed, built, commissioned on a truck, trialled on a truck for six months and demonstrated to industry and MAF representatives.

Background

The system senses temperature and humidity in a section of the trailer unit which previous research has shown to be the warmest. The information is transmitted from the remote trailer to a `base' computer as an email. Thus the base computer can be used to provide a permanent record of the climatic conditions.

Approach & Outcomes

The system computes the standard Temperature Humidity Index (THI) indicator of environment-induced heat stress and if this exceeds preset thresholds, warning and then alarm messages will be sent to both the driver's cellphone and to the base computer.

The system is totally stand-alone and has been designed to operate when the trailer is detached from the truck unit, the time of operation in this mode is only limited by battery life which is currently ~ 12 hours. The batteries are rechargeable and are recharged once the trailer and truck are reconnected.

The system has been designed to be ergonomic, robust and easy to retrofit. The success of the six month trial suggests that these goals have been met.

The trials and demonstration have proved that it is technically feasible to monitor the climate in stock trucks and provide real time information for decision making.

1.9 FMA 128

Programme Title:

Food Safety pathogens

Programme Leader:

TeckLok Wong

Institution:

ESR CRI

Background

This report is an output from the MAF Policy project FMA 128. The scope of the project was to carry out the qualitative and, if present, quantitative measurement of pathogens on fresh lettuces and apples, as identified by the risk ranking assessment in Objective 1. In this first objective, ESR presented a report on "Risks associated with bacterial pathogens in exported fruit and vegetables" (Hudson and Turner, 2002) in which the food/hazard combinations of Escherichia coli O157:H7 on lettuce and Salmonella on apple were recommended for sampling.

Export trade of lettuces is minimal, so it was necessary to sample the produce available in the local market to obtain a sufficient number of samples. Apples are exported in large volumes so sampling was carried out at export packhouses. The aim of the sampling plan was to obtain as many varieties of produce from as many growers as possible. The project recognised the need to sample as close to the point of packing as possible to avoid downstream recontamination problems.

Between the months of February and May 2003, 240 conventionally grown lettuce and 234 organically grown lettuce samples were tested for E. coli O157:H7; and between the months of March and May 2003, 239 samples of apples grown under the Integrated Fruit Production programme (IFP) and 230 organically grown apples were tested for Salmonella.

Conventional lettuces (48 lots of 5 samples) were obtained from 22 growers from around New Zealand. Seven varieties were included, with Iceberg being the variety most available in the market. All samples tested negative for pathogenic E. coli O157:H7 per 25 g of sample.

Organic lettuces were purchased from 9 growers from around New Zealand. Forty-six lots of 5 samples and one lot of 4 samples were purchased, representing 13 varieties with Iceberg, Fancy green, Green oak and Cos being the most popular. All samples were negative for E. coli O157:H7. However an atypical E. coli O157:H16 was isolated from one Fancy green lettuce with a count of 23 MPN per g. This isolate harboured the eaeA adhesin gene, one of four recognised in pathogenic E. coli O157:H7. The stx1, stx2 and hlyA genes were absent. Verocytotoxin was not produce by this isolate. It was concluded that this isolate was of dubious, and most probably, no public health significance. The fact that verocytotoxin was not produced made this isolate a curiosity of no concern.

239 IFP and 230 organic apples were sampled from export packhouses in both North and South Islands. Eight varieties of IFP apples and five varieties of organic apples were sampled. Braeburn, Royal Gala and Fuji apples were the most popular. No Salmonella was isolated from any IFP apple samples. However, one batch of 5 samples of organic Braeburn apples 91

on the same orchard tested positive for Salmonella Typhimurium DT12a. Due to the nature of the test procedure, where the 200 ml volume of rinse was divided into 35 ml and 165 ml portions, initial individual large portion testing was negative for Salmonella. It was only when these five smaller 35 ml portions from the batch were pooled and tested that Salmonella was isolated.

Approach & Outcomes

From the results, we do not know how many samples out of five were contaminated or if only one sample was contaminated whether only one apple out of three in the sample was contaminated. It was likely that the level of contamination was very low since the larger individual rinse portion tested negative and only the pooled test of five smaller 35 ml portions was positive. It may be possible to deduce from this that perhaps only one apple in the sample was likely to have been contaminated with only one or a few Salmonella cells to return a positive pooled test. If this was the case, then the prevalence would be as low as 0.4% positive out of 230 organic samples.

This study demonstrated the benefit of introduction and effective implementation of HACCP based food control programmes in the edible fruit and plant product industries. Vigilance over approved programmes needed to be reinforced, as these pathogens are present in New Zealand. Establishing critical control points or adopting control measures would minimise the potential of having hazardous pathogens in edible plant products.

1.10 FMA 129

Programme Title:

Salmonella in sheep meat (2)

Programme Leader:

Michael Baker

Institution:

ESR CRI

Summary

Consumer/health component of a quantitative risk assessment of Salmonella spp. in sheep meat produced in New Zealand.

Background

To quantify the incidence of human infection with all Salmonella spp. inclusively and S. Brandenburg specifically, to estimate the contribution of New Zealand sheep meat consumption to this incidence, and to provide comparative information to validate the MAF Quantitative Risk Assessment (QRA) model for the sheep meat supply chain in New Zealand.

Approach & Outcomes

Non-typhoidal salmonellosis has been increasing in New Zealand for several decades and reached its highest annual incidence of 2417 cases in 2001. A new strain of S. Brandenburg appeared in animals in 1996 and subsequently caused outbreaks of abortion in sheep in the southern half of the South Island. This organism began causing large numbers of human infections in 1998. The presence of S. Brandenburg infection in sheep raised concerns about the potential for this organism to become an important foodborne pathogen in sheep meat. Consequently, MAF initiated a QRA model to estimate human health risks due to Salmonella exposure as an end result of the sheep meat supply chain. This project aims to provide human health information to compare with, and validate, the QRA model.

Approach

This investigation had three components:

  • A detailed epidemiological description, using combined laboratory and notification data, of human salmonellosis in New Zealand for the period 1995-2002. Data on isolates referred to the enteric reference laboratory from animal health laboratories were also analysed.
  • The literature was reviewed to estimate the degree of under-ascertainment of the salmonella surveillance system.
  • A national case-control study was undertaken to estimate the contribution of food, water, environmental, animal and human exposures to the incidence of salmonellosis. This study included all S. Brandenburg infections from January 2002 to April 2003, and a one-in-nine sample of other salmonellosis cases occurring over that period. Controls were recruited by random digit dialling. A conditional logistic regression was performed on the matched data for both univariate and multivariate results.

Outcomes

There were 1810 laboratory confirmed notified cases of salmonellosis in New Zealand in 2002, a rate of 48.4 per 100 000. Incidence rates rose markedly during the 1995 to 2002 period. This disease is highly seasonal with peak incidence typically in late summer around March. Rates are highest in children under 5 years of age.

S. Brandenburg has historically been an uncommon cause of salmonellosis in New Zealand, accounting for 2-3% of cases from 1995 to 1997. Its incidence rose markedly in 1998, with this serotype causing 8-10% of cases over the 1998-2001 period. This incidence rate now appears to be declining. It caused 81 cases in 2002, 4.5% of total salmonellosis, giving a rate of 2.2 per 100 000.

S. Brandenburg infection in humans is intensely seasonal, with cases peaking in spring, particularly around September. Cases are also highly concentrated in the Southern half of the South Island, particularly in Southland, Otago, South Canterbury, and Canterbury health districts. Animal isolates of S. Brandenburg have shown a similar temporal and geographic pattern to human disease. There has been a marked increase in the referral of isolated from 1998 onwards. Most (80%) have been from ovine sources (sheep, lambs) and the majority has been from animal health laboratories in the Southern half of the South Island.

For S. Brandenburg infection, two exposures were associated with a significant increase in disease risk in the multivariate analysis. Occupational contact with live or dead sheep or lambs during the 3 days prior to illness, or interview (OR=9.97, 95%CI 1.62, 196.29); and having a household member who had occupational contact with sheep or lambs in the 3 days prior to illness or interview (OR=4.28, 95%CI 1.23, 21.31). Collectively these two exposures were able to explain a high proportion (88%) of the population attributable risk for this infection. There was no significant association between eating lamb, mutton or hogget in the 3 days before illness or interview and either the risk of salmonellosis or S. Brandenburg infection.

The literature review suggested that a reasonable correction factor for adjusting the rate of salmonellosis from notification data was 3.5. The estimated rate of S. Brandenburg infection in New Zealand in 2002 was therefore 7.7/100,000, or 284 cases. The contribution of sheep meat consumption to this total is estimated at 0.00 cases / 100 000 with an upper 95%CI of 3.0 cases / 100 000, or 111 cases

This study provides good evidence that S. Brandenburg has not become a food borne disease transmitted by sheep meat consumption. Instead, this pathogen is an important zoonotic disease that represents a risk for farmers and others who have direct occupational contact with infected sheep and family members who have indirect contact with the farming environment.

This study also provides, for the first time in New Zealand, some evidence regarding the sources of sporadic salmonellosis at a population level. It confirms the importance of zoonotic transmission (either from contact with bird faeces or from handling pet puppies); food handling practices and cross-contamination within the home; attendance at the same meal or gathering where others also got sick; and overseas travel.

Summary

This project aimed to quantify the incidence of human infection with all Salmonella spp. and S. Brandenburg specifically and to estimate the contribution of New Zealand sheep meat consumption to this incidence. This information will be used to validate the MAF Quantitative Risk Assessment (QRA) model for the sheep meat supply chain in New Zealand.

This investigation used a detailed epidemiological description of human salmonellosis in New Zealand for the period 1995-2002 and data on isolates referred to the enteric reference laboratory from human and animal sources. The literature was reviewed to estimate the degree of under-ascertainment of the salmonella surveillance system. And a national case-control study was undertaken to estimate the contribution of food, water, environmental, animal and human exposures to the incidence of salmonellosis.

The adjusted incidence of S. Brandenburg in 2002 was 7.7 per 100 000, or 284 cases. There was no significant association between eating lamb, mutton or hogget in the 3 days before illness or interview and either the risk of salmonellosis or S. Brandenburg infection. Instead, the risk of S. Brandenburg infection could be largely attributed to two exposures: occupational contact with live or dead sheep or lambs during the 3 days prior to illness or interview and having a household member who had occupational contact with sheep or lamb in the 3 days prior to illness or interview.

1.11 FMA 131

Programme Title:

Alternatives to Methyl Bromide as a Quarantine Treatment for Forestry Exports - Literature Review

Programme Leader:

Peter Dentener

Institution:

HortResearch CRI

Summary

Goal: To undertake a literature review of alternatives to methyl bromide as a fumigant for forestry exports.

Background

Methyl bromide (MeBr) is an ozone depleting substance widely used in New Zealand for treating quarantine pests. New Zealand has signed the Montreal Protocol that requests parties to monitor their own use of MeBr, identify opportunities for research into alternatives, and to encourage the use of alternatives and/or recovery where feasible. This project reviews the literature to identify alternatives to MeBr for quarantine and stored product use that could be used for disinfesting logs and forest produce.

Approach & Outcomes

Approach: Extensive searches on alternatives to MeBr fumigation were carried out using library and internet resources. Where possible, unpublished material was sourced and/or relevant researchers contacted directly.

This review summarises and discusses available options and provides recommendations, bearing in mind (a) New Zealand exports short rotation grown softwood logs, which have a very high moisture content; and (b) New Zealand's distance from markets which could be utilised by using environmentally less harmful longer duration treatments.

Outcomes: The report documents a range of alternatives, ranging from chemical fumigants and biocides to physical treatments and handling practices. Recommendations have been divided into those which can be implemented (almost) immediately (short term), and those which require further research and infrastructure development before commercialisation (medium to long term). The ultimate goal should be commercially viable and environmentally sound treatments, which have minimal impacts on human health and the environment while providing a high level of quarantine security.

We recommend that investigating the following short, medium and long term alternatives be a priority when considering a replacement for MeBr fumigation of timber products in New Zealand:

Short term options (1-3 years) - Fumigation with phosphine seems to be the best candidate, however sulphuryl fluoride should also be considered. Because of insect resistance to phosphine and sulphuryl fluoride's low efficacy against egg stages, these solutions should only be considered in the short term while research is carried out into long term solutions.

Medium term options (3-10 years) - Methyl iodide and carbonyl sulphide treatments are in the process of registration. However, more research will need to be undertaken on the use of these fumigants in wood. Heat treatment, particularly steam, is a highly attractive medium to long term option. While infrastructure requirements are likely to be high, the volume of research, and acceptance of heat as a treatment makes this option worth pursuing.

Long term options (10+ years) - Treatments worth pursuing in the long term include ozone fumigation (a GRAS compound), irradiation treatments and possibly microwave and radio-frequency treatments.

Summary: A literature review of alternatives to methyl bromide as a fumigant for forestry exports.

Methyl bromide is facing increasing restrictions on its use, and acceptable and effective alternatives are required to maintain exports of New Zealand wood products to overseas markets. An extensive literature review was carried out using library resources and the internet, and a range of alternatives identified.

Short term, fumigation with phosphine and sulphuryl fluoride should be considered as replacements for MeBr. However, due to insect resistance to phosphine and sulphuryl fluoride's low efficacy against egg stages, a longer term view needs to be taken. The following options may require further research and/or investment in infrastructure. Medium term, methyl iodide and carbonyl sulphide treatments have potential but more research will need to be undertaken on their use as wood fumigants. The volume of research, and acceptance of heat as a treatment makes this option worth pursuing. Long term options include ozone fumigation (a GRAS compound), and irradiation treatments.

Publications

L.E. Jamieson, A.E.A. Stephens, P.R. Dentener. 2003. Alternatives to Methyl Bromide as a Quarantine Treatment for Forestry Exports - Literature Review. Report to MAF Policy. HortResearch Client Report No. 9746. 84 pp.

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Farm Monitoring Programme Manager
Monitoring and Evaluation
MAF Policy
PO Box 2526
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NEW ZEALAND
Phone: +64 4 894 0623
Fax: +64 4 894 0741
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