Current and Recent Projects

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To Alma Baker trustee board
Report of NZMRM activities at Limestone Downs test exposure site.

Please refer to Appendix for background on why we are doing this research.

May 2018.


We recovered and tested the 1-year set of steel coupons by which assess the corrosivity of the site using ISO 9223 methodology. The outcome is that the site – over that whole year – rated at the bottom of category CX. This is the most severe corrosion category and means this site is the most corrosive (and so good for assessing products) of the seven sites we have had or looked at. A further set of coupons were installed as part of the ongoing site assessment.

Exposure racks

In this same month we erected a set of post and rail racks for general use for exposing test materials. This was not without difficulty and illustrates the remoteness and limited access of the site.

Flashing tests

Our first set of exposures here is a range of assemblies intended to assess the possible corrosive effects of various eaves flashing materials in contact with different roof cladding materials. We are seeing an increasing demand for use of eave flashings and it is important to understand the interactions of different materials in a corrosive environment (most of NZ!)
Some photos of this installation are attached.

December 2018

We intend to install a second set of posts for a second general purpose racking.

April 2019

We plan to install a set of racks containing roofing screws made using new coating technology onto special frames these posts and at the same time will replace the steel coupons placed in May 2018. We will also do the first-year inspection of the flashing racks installed in May 2018.


Stuart Hayman

For NZ Metal Roofing Manufacturers Inc

November 2018

I would like to commend the invaluable help, advice and assistance provided by Paul Mahony without whose help nothing would have happened.


Appendix – background to exposure testing

Manufacturers in both domestic and foreign markets supply products which are expected to perform for extended periods in a range of environments (from mild to very severe). To meet either regulations or customer demand, manufacturers do produce items of different qualities depending on the environment.

Products used externally are subject to both solar (heat and ultra violet light) and/or marine (corrosion) aggression. In NZ the Building Code has minimum (durability) periods for a range of building products (e.g. roof sheets, which can be relatively easily be replaced, must have a life of 15 years, irrespective of the environment). Structural components or materials which can’t be easily be replaced (or accessed) require a 50 year life.

Manufacturers, to meet the durability requirements of their products, undertake testing to ensure the product is fit for purpose. To speed up new product development manufacturers attempt to accelerate their product testing (using standardised procedures) to show their product will perform in their designated environment.

For corrosion, some testing is carried out in laboratories using cyclic corrosion equipment (with known salt concentrations, drying periods, and temperature) for periods which can exceed 12 months. However, the results do not always align with real world experience. It is for this reason that there is a requirement for external testing in very severe marine environments. Development of products which fail the external exposure are removed and alternatives developed, which will also have to undergo the external exposure testing. It is better fail on the testing rack than on a building 10 years later.

The NZMRM has been conducting series of tests since 2005, on both roofing metals (e.g. aluminium and coated steel) and fasteners. As we (and the manufacturers) have learned from each set of tests the products have improved – and the testing regimes have become tougher and better assessed.

To determine the suitability of a site for corrosion testing, the site must be categorised according to its corrosion level. There are six categories, C1 (Mild as in central Australia) to C5 (very severe marine) and the most corrosive CX. The other sites the MRM had established were in C3 to C5. The site at Limestone Downs after measuring the corrosion rates on the steel samples put out last year is a CX. This makes it our most suitable site to date for the improved products previous testing has encouraged development of.

Approved November 2017

Name Institution Project Approved
Dr Rene
Inst of Vet, Animal & Biomedical Sciences
Massey Uni
The impact of offering reticulated water on ewe productivity and behaviour. $14,090
Dr Rao
Inst of Vet, Animal & Biomedical Sciences
Massey Uni
Exploring genetic variation of skin thickness and its association with economically important traits in different sheep breeds. $19,500
Dr Nicola
Inst of Vet, Animal & Biomedical Sciences
Massey Uni
New Generation Beef: creating a new class of beef using surplus calves from the dairy industry. $36,150


Sheep & Beef Block

Postgraduate Scholarships Update:

The C. Alma Baker Trust (Limestone Downs) continues to support scholarships for students completing their postgraduate studies.

The following Research projects have been completed with some interesting results. Read on to find out what they are…

For the sheep industry three different projects were funded. They are:

1. Factors affecting the productive longevity of ewes

AL Ridler, RA Corner-Thomas, PR Kenyon and KJ Griffiths (PhD student) wanted to understand the types of factors that influenced how long ewes remain productive during their lifetime.
In order, to measure the factors of individual performance, length of productivity, weight loss and deaths in the ewes, the team individually tagged all hoggets born during the seasons of 2010 and 2011.

The study monitored 8,000 animals on several large farms including Limestone Downs and Castlepoint, by weight and body-condition score four times a year. This method captured the ewes performance at pre-mating, pregnancy scanning, pre-lambing and weaning. In addition, their pregnancy scanning details such as whether they were carrying a single, twin or triplet lambs and their ability to rear their progeny were also recorded.
Autopsies were undertaken on 82 dead study ewes in 2013 and 2014 to assist the team’s study analysis.

So far, with the data set now complete, the team have made an interim summary that if hoggets and ewes are to be successful mothers and rear their lambs they need to be in good body condition and it is important to reduce the number of small, slow-growing sheep with poor body condition. This identification of the at-risk sheep can be done prior to winter and then they can be feed preferentially to improve their productivity success.

The next steps for the study are to identify the relationship between production factors and the length of time the ewe remains in production.

2. Identifying the magnitude and causes of ewe hogget and their lamb deaths at Limestone Downs

Three members of the same team in the above study, AL Ridler, RA Corner-Thomas and PR Kenyon undertook to study the timing and reasons for any mortalities in ewe hoggets and their lambs and to monitor if there are any production effects through pre-lambing anti-parasitic (anthelmintic)capsule treatment.

The study was carried out at Limestone Downs from December 2014 to 30 June 2016 with 489 hoggets successfully mated in the first eight days and who were carrying a single lamb. The weight and condition body score of each animal was recorded at:

  • The time of mating;
  • Pregnancy scanning;
  • Prior to lambing;
  • Docking; and
  • Weaning

During lambing they were monitored twice daily to make sure the dams and their lambs were matched and the birthweight of the lamb could be recorded. Any deaths of the hoggets and/or their lambs were autopsied to identify the cause of death. At the time of docking and weaning the lambs were also weighed. Only half of the 489 hoggets received a pre-lambing anti-parasitic (“Bionic”) capsule.

For the lambs their survival had many variables such as genetics; weather at the time of birth; the individual mothering ability of the hogget; and their size at birth. The smaller and larger lambs being more at risk of not surviving. Interestingly, the study found no relationship between the survival of the lamb and the administration of an anti-parasitic capsule to their mother.

However, there was an increase in the weaning weight (average 1.3kg) of the lamb if their mother had received a capsule. Unfortunately, the value of that increase in live weight (at the time of the study) equalled the cost of the capsule. The hoggets who had received capsules had an average of 1.4kg increase in their weight at weaning but it is unknown if this translated into an increase in two-tooth mating weight. Follow up research wold be required to test this idea.

The results of the study showed the only significant association between hogget lambing success; hogget live weight; growth rates; and body condition score was that the heavier the hogget was at mating the more likely they were to rear a lamb successfully.

Other results from this study concluded that the main cause of death for the lambs and some of the hoggets was a difficult birth which could possibly be minimised through hogget mating weights being greater than 40kg, choice of the rams used and a lambing beat being undertaken on a daily basis to assist the hoggets in difficulty.

3. The effects of facial eczema on ewe hogget performance and beyond

Unfortunately, due to cold and wet weather conditions for the summer and autumn of 2016/2017 spore counts did not rise enough for this study by AL Ridler, RA Corner-Thomas and PR Kenyon to be undertaken so the research is to be held over until the summer and autumn of 2018 – 2019.

 In the dairy and beef sector three equally interesting studies were completed. They are:

1. Early-life infection of calves with Theileria in an endemic area

This study by R Hickson, L Fermin, L Coleman, K Gedye, K Lawrence and B Pomroy looked into when calves became infected by the tick-borne parasite (Theileria orientalis Ikeda) which can cause anaemia in cattle and what influence birth date and time spent in a calf shed may have on timing of infection in calves.
Limestone Downs provides an ideal environment, having both dairy and beef units, to undertake this study as there are reports that there is a difference to susceptibility of calves being infected between dairy and beef herds. The result of this difference is the greater loss of beef calves because of the disease.

Three groups of 50 calves were selected for the trial which represented calves being born either at the beginning, in the middle or late in the calving period on the farm.
All calves had 24 hours on their mothers before being transferred to the calf-rearing shed and generally were housed for up to six weeks, depending on shed capacity, before being moved outside onto pasture.

All the early and middle calf groups were blood tested for Theileria before leaving the calf shed. Only the middle and late groups were tested after four weeks (42-65 days old) and eight weeks (70-93 days old) outside on pasture.
The late group of calves born were blood tested at 17 days of age which was just over half the time they were in the shed. The blood test results were interesting.

After the first test on entry to the calf shed, but prior to going outside, no early or late born calves had Theileria but four out of the 50 in the middle group did contract Theileria.

In the second blood test, after four weeks on the pasture, calves were shown to have picked up Theileria but it depended on when they were tested. For example, those tested at the beginning of October (the middle group) had fewer positive tests than those tested at the beginning of November. This comes as no surprise given there is greater tick activity in November than October.

The final blood test after eight weeks on the pasture showed that the late group (84%) had the higher infection of Theileria than the middle or early group. For a farmer this would be significant and care may need to be taken with these animals regarding stress and access to plentiful feed.

The team concluded that there is no infection prior to entering the calf shed but as the tick population intensifies in November and December, calves outside are more prone to infection which can lead to calves dying unexpectedly. Therefore, it is important at this time to minimise any potential stress on the calves such as feed shortages to prevent unnecessary losses.


2. Investigating the cause of humeral fractures in New Zealand dairy heifers

In some dairy herds, a number of first-calving heifers are incurring humeral (from the shoulder to the elbow) fractures and have to be put down. This can incur a financial loss to the individual famer and the greater dairy industry. This is a relatively new phenomenon, with the first case being reported in 2008 in the Manawatu.

Therefore K.E Dittmer, J.F Weston, K Lawrence and C.W Rogers investigated the risk factors that may cause these fractures in dairy heifers and to make some treatment recommendations and management changes to prevent the development of the osteoporosis and the subsequent risk of fracture in what is a relatively new condition.

The method the team undertook for this study was to have data recorded from farms that experienced such fractures(case) and farms that did not(control). Unfortunately, despite a massive effort to get participation from vets and farmers only nine case farms and seven control farms completed the survey.
The information the team were looking for included:

  • How the calves were reared and fed;
  • Growth weights;
  • If there was any trace element supplementation;
  • Other supplements fed; and
  • Had there been any ‘dropped hock syndrome’.

Due to the small sample size no conclusions could be made which is a loss for the dairy industry. The only comments the team could make were that the farm practices on the case and control farms were similar and that further effort to get more surveys completed will be undertaken.

3.Right on the tip of their tongues

 Quite by accident an Angus breeder discovered a tongue colour test trend. Lucy Coleman, a Massey University PhD student took up the challenge to see if a new-born calf tongue could be a clue to identify its breed given the difficulty to separate an Angus-cross and Holstein-Friesian-Jersey calf when their coats a completely black.

Of course, each calf could be DNA tested but this is an expensive and time-consuming method and the tongue test has potential to be effective and efficient especially if it can be completed within the first four days after birth.

So, what is the trick to tell the difference.

According to Lucy “Holstein-Friesian cattle possess a gene which causes the white patches in the coat and a pink coloured tongue, whereas Angus and Jersey cattle lack this gene and have black tongues.

 476 Angus-cross-dairy and dairy calves were selected shortly after birth for the study.

The results of this study showed that by just selecting calves to rear for beef solely on having a black-coloured tongue, would accurately identify 73 per cent of Angus-cross calves and 90 per cent of dairy-breed calves.

 Of course, there was the issue of spotted tongues so the use of tongues is not infallible but still a valuable tool for farmers at a busy time of the year. To enhance the study a follow-up research programme undertook to record the presence of horn buds at birth plus tongue colour of 418 Angus-cross-dairy and dairy calves. The numbers again were positive, in that 95 per cent of the dairy calves identified with horn buds at birth were dairy.

On the other hand, no horn buds were found for the Angus-cross calves. Two very quick and useful tests for calf- rearers to use when purchasing stock.


4.New generation beef

 The New Generation Beef study by Nicola Shreurs, seeks to develop a new system of beef production which utilises surplus calves from the dairy industry by growing them for beef production with slaughter before one year-of-age.

A pilot study, funded by the C Alma Baker Trust, has been implemented to consider the carcass and meat characteristics of Kiwicross x Hereford steer at 8, 10 12 and 18 months of age.  

It is considered that New Generation Beef will have an impact by minimising the welfare concerns associated with transporting and slaughtering very young bobby calves and reducing environmental foot print due to animals being on farm for less than a year. It is also considered that there will be benefits for feed efficiency, feed budgeting and winter sensitive soils due to only feeding animals during their accelerating phase of growth, with animals processed for beef prior to the first winter, reducing the stock units over the winter period. Initial results show a carcass weight of 120kg at 8 months of age and 145kg at 10 months of age.  The meat from the 8 and 10 month cattle is red, lean and exceptionally tender, even without aging. The beef flavour is mild compared to older, pasture raised cattle.

The study is continuing.

 schreurs nicola 2017