Reporting on HT swedes


provided by Jodie Bruning:
September 14, National Radio – Swede death linked to leaf growths: Reports so far indicate that 200 to 300 dairy cows may have died after grazing on swedes, a common winter feed crop in the south, and that 30 to 50 farms may be affected – mainly in central and lowland Southland.
Vets say autopsies are showing signs of significant liver damage and in some cases kidney damage in the cows. PGG Wrightson supplies most of the swede seed and said there appears to be a connection with a higher level of leaf growth in swede crops due to the unusually mild winter in the region.
Scoop reported: Questions Raised Over Cow Deaths, 15 September 2014: MPI and EPA must explain how come they have allowed use of a novel mutagenic food crop that is able to resist intense spraying with herbicides? This crop has been developed using a highly controversial technique of mutagenesis with the chemical Ethylmethane Sulfonate (EMS). EMS is a systemic mutagen that causes irreversible health effects, deformities and cancers. In animal tests it has been shown to be fatal in small amounts.
The Lincoln team who developed the seeds for PGG Wrightsons involved Dr. Tony Connor who is a lead promoter for GMOs. “Is there a relationship between the seed saved from the failed GE brassica lines and the development of this new toxic HT line now being sold?” Press Release: GE Free NZ.
On the 29th of September 2014, Rob Tipa reported in Stuff that ‘Massey University veterinary pathologist Dr Mark Collett advised that swede crops have sporadically caused liver disease and photosensitivity in cows in Southland over the past 10 or 20 years….. Collett says there is no evidence in any scientific literature of glucosinolates or glucosinolate derivatives ever being toxic to the liver of ruminant animals.
However, he speculated that one derivative, known as nitriles, may have been responsible for liver damage he had previously observed in cows fed on turnips. In the 1960s and 1970s researchers showed in trials that rats developed liver and kidney damage from nitrile derivatives.
”This big outbreak in swedes in Southland is a wake-up call that something is damaging the liver,” he said. ”It could be the cows are eating too much swede in too short a time, transitioning is too quick or a particular variety of swede is too high in glucosinolates – or it could be something else, because there is no proof at this stage that glucosinolates are the cause of the problem.”
In September Richard Dunwell wrote to the Environment Southland, he advised: Chlorsulfuron is the active ingredient (75%) in Telar XP. The other 25% are “inert” ingredients. It will probably come as some surprise that China revoked the registration of chlorsulfuron products as of 31 December 2013 and they will be banned as of December 31, 2015 due to potential environmental and health risks and serious adverse events, despite their amending standards in 2005/2006. Chlorsulfuron is being banned due to its excessively long residual effect, the high level of skill required to apply it safely and its phytotoxicity to follow-up crops. I.e. it may kill them or reduce yield. Like all sulfonylurea herbicides It has the potential to leach to groundwater and reach surface water through runoff.
October 6 Rob Tipa in NZ Farmer Pregnant Cows in Swede Death Warning advised sales will carry a warning that in future ‘endorsement was likely to exclude pregnant dairy cows’ PGG Wrightson Seeds Manager David Green said.
October 22 Radio NZ reported: PGG Wrightson Seeds general manager David Green said it is far from certain that HT Swedes are the culprit ….. “We’ve adopted what we believe is a very prudent approach, which is to recommend that HT Swedes will not be fed to pregnant dairy cows.
“That’s where the vast majority of cases have been reported and I think the advice would be that they represent the most volatile stock class that is likely to be fed on brassicas.”
A press release from Dairy NZ in Rural News January 24, 2015 stated : ‘Blood and autopsy samples from cows that were sick or died after grazing swedes in Southland last winter have confirmed liver damage but the role, or not, of the HT strain of the crop in the epidemic is still unclear.
“While the study did not allow comparison between swede varieties, the findings indicate that cows experienced liver damage after grazing swede varieties other than the HT (herbicide tolerant) variety, regardless of whether there were visible signs of illness,” said Dairy NZ’s regional team leader Richard Kyte in a media statement released December 23.
Last week Kyte declined to reveal the data behind that statement for fear of wrong or invalid conclusions being drawn from what was “just one bit of data” in the ongoing investigation.
“These samples were from just 15 farms late in the piece and we have no further information on these farms at this point so this data really is in isolation,” he told Rural News.’
A letter to Rural News Group January 25 2015 by retired veterinary surgeon Frank Rowson insisted that more questions should be asked regarding the swede issue: ‘It is now four months since Rural News first reported on the deaths of Southland cows on swedes so I thought it would be a good time to determine that the investigation is on track and the correct questions are being asked.
Farmers should be asking that the following tests be done:
• trace element levels in soil, plants and animals;
• blood and urine tests for metabolites of chlorsulfuron and soil tests for chlorsulfuron;
• glyphosate levels in swedes and baleage fed with swedes, given it may have been sprayed before baling;
• comparison of gut biome in affected cows to healthy cows and levels of botulism toxins’
Dairy NZ reported in ‘Southland Swedes get Scientists Scrutinising’ February 11, 2015: ‘Because affected cows presented with symptoms suggesting liver damage, the blood testing looked at liver and kidney function.
The disease condition appears to be consistent with known forms of liver damage associated with cows grazing brassica forage crops, but with clinical signs that are more severe.’
On 6 May Radio NZ Benedict Collins reported: Test results have revealed that herbicide-tolerant swedes planted as stock feed have unnaturally high levels of toxins that cause liver damage in livestock. …
Documents obtained by Radio New Zealand show the Southland Swedes Working Group was told in October there was a problem with the herbicide-tolerant swedes.
It was told that the leaves of herbicide-tolerant swedes had levels of glucosinolates, which are toxic to cattle, up to 16 times higher than in a natural plant.
The herbicide-tolerant swede leaves had glucosinolate levels of up to 16 milligrams per kilo and the bulbs up to four milligrams. The working group was told those levels “certainly indicate problems” with the crop….
MPI believes mild weather in Southland last winter may have encouraged more leaf growth than usual.
It said the herbicide-tolerant swedes were created by chemical mutation, which it said was not considered to be genetic modification, and that the swedes were tolerant to the herbicide chlorsulfuron, which was recently banned in China.
Natural brassica varieties have glucosinolate levels of one milligram per kilo.
Swede advisory update #8 13 May 2015 – Dairy NZ: DairyNZ plans to release its full report on the study we have been conducting in June when our analysis of the farmer survey data is complete and the preliminary plant analysis has become available.
On May 29th 2015, Dairy NZ reported in ‘Swede survey results show multiple factors to manage’: DairyNZ carried out the survey between November 2014 and February 2015 to help understand the factors that caused some cows in Southland/South Otago to die or become ill. In total 134 affected and unaffected farmers and 34 graziers were interviewed as part of the survey.
DairyNZ’s Southland/South Otago regional leader Richard Kyte says the chemistry of glucosinolates for swedes and other brassicas is complex. It changes with swede variety, growing conditions and crop maturity. Further complexity is added when the glucosinolates are changed during eating and digestion.
“The results of our survey confirm that all varieties of swedes can present a risk to animals depending on how and when they are fed and used as part of the farming system. If farmers plant swedes, and many have this season, then they need to manage how and when they feed it to their cows.”
Richard says the next update for farmers will be when plant analysis results are available. “This update is expected to be available to farmers in late July and that will be an important piece in the puzzle. We can then focus on pulling together our final consolidated report on all the elements of the work we have done on the issue.”
DairyNZ has already set in train a number of steps for helping farmers this season.
“While we are continuing the plant analysis, unfortunately there are no quick tests for swede plants that will provide an early warning signal for farmers,” he says.
“However, DairyNZ is working with farmers this season to identify early signs of ill-health in animals by monitoring a small selection of cows. We are compiling blood samples from cows and want to record incidences of ill-effects throughout this season. This kind of work is the first step in assessing how we can develop a baseline system for detecting early signs of ill-health in cows. This work, along with our final report will help us know what’s important and useful to study going forward,” says Richard.
“The survey has thrown some light on a shift in farming management practices in Southland and South Otago in the last 10 years as a contributing factor.
On June 2 2015 Steffan Browning stated on National Radio: “More testing is needed to determine exactly what chemicals are in these plants and their safety or lack, thereof.
“We could be looking at what the connection is with the mutagenesis that the seeds were created from, the chemicals used in the farming process, and whether the natural toxins have been enhanced by any of those processes.”
David Green, general manager of PGG Wrightson Seeds, which sells the HT swede variety, said it did consider stopping sales, but decided instead to provide farmers with detailed precautionary advice about using the swedes.
“What we chose to do in particular in relation to the HT swedes was issue an endorsement to everybody who purchased those products, which clearly spelt out the issues that had occurred during the 2014 year and further, made a recommendation that those crops are not fed to pregnant dairy cows, bearing in mind that dairy cows are only one class of stock that are grazed on swedes.”
An extract from a June 7 letter Frank Rowson wrote to Kevin Ikin in response to the National Radio coverage: ‘The breadth of the investigation is far too narrow. It has come to light that the glucosinolate levels are 16 times higher in the GE swedes. Why? is this just one of the “unintended effects”, common to all GE crops that should have been investigated or is it due to the fact that increased levels of chlorsulfuron and other pesticides are used in the cropping system and I refer mainly to the use of glyphosate based herbicides (GBHs) both in land preparation and the drying off of pasture prior to baylage/silage/grazing.
My research over the last few years indicates that GBHs will produce many of the symptoms shown by the affected cows both directly and indirectly by the fact that they are:-
a. antibiotics
b. endocrine disruptors and will have long term effects on fertility
c. neurotoxic- cause nervous signs like recumbency
d. classified by WHO as probable cancer causes and
e. they destroy enzymes, mainly in the liver, that detoxify other toxins (zenotoxins) and produce bile salts, thus allowing in this case the buildup of chlorsulfuron and glucosinolates.
Thus it is essential that these aspects, and others I haven’t mentioned, be investigated by an independent panel, i.e. does not include agencies with conflict of interest- PGG Wrightson, Hort. Research, Federated Farmers. A definitive conclusion will not be reached otherwise.
It is also essential that pesticide levels are measured at independent laboratories with up-to-date methods, because recent experience has suggested a lack of expertise and methods in use in this country
Because recent experience has shown the reluctance of the media to cover the issues of GBHs and food safety and GE I would welcome the opportunity to enlarge on this very serious, wide-ranging issue. Regards, Frank Rowson, B.Vet.Med. retired veterinary surgeon

Brittany Pickett reported in Stuff – DairyNZ: use caution with HT swedes and fodder beet June 9 2015: ‘VetSouth Winton veterinarian and director Mark Bryan said the issues with HT swedes and fodder beet were separate but both related to transition periods.
The veterinary practice had been notified of two issues with fodder beet in the past two weeks, while they had three or four farmers with dying cattle after transitioning to HT swedes, he said.
Three or four days after the farmers had begun to transition their cows onto the HT swedes a number of them had become sick, he said. “We haven’t had any reports of disease with any other swedes.”
For those with cattle dying or becoming ill, vets were telling farmers to stop using the HT swedes as feed. “We’ve advised them off the swedes and to find some other feed,” Bryan said.
He urged farmers to get in contact with their vets to report deaths or sickness.’
On June 10 Evan Harding reported in Stuff ‘HT swedes should be pulled off market: Green MP’: ‘Green Party MP Steffan Browning has called for HT swedes to be pulled off the market in the wake of more dairy cows dying after eating the crop.
However, PGG Wrightson Seeds, the company which sells HT [herbicide tolerant] swedes, said it had no thoughts of taking the product off the market at this stage. ….
Investigations were launched following the stock deaths and illnesses last year. And the Ministry of Primary Industries revealed in March that an initial assessment found the cause to be high concentrations of glucosinolates, a toxin which naturally occurs in brassicas and is toxic to cattle.
A ministry spokesman said the industry led investigation was ongoing.’
Toxic swede test results not definitive – MPI: Radio National reported on 15 May 2015: The Ministry for Primary Industries says test results showing high toxin levels in herbicide tolerant swedes weren’t definitive enough to warrant restricting the sale of the crop to farmers this season.

References and information:

[1] US EPA NOAEL: Alvarez, L. 1991a. Teratogenicity Study of DPX–W4189 (Chlorsulfuron) in Rabbits. E.I. du Pont de Nemours & Company, HaskellLaboratory for Toxicology and Industrial Medicine, Newark, DE, Laboratory Project ID:306–390, August 12, 1991. Unpublished
[2] Details of toxicity studies (only provided by the chemical company, in this case DuPont) appear most clearly in the US EPA Federal Register.
[3] EU study – unclear as no reference provided – possibly:
Wood, C.K., Wollenberg, E.J., Turner, D.T., et al. 1981a. Long-Term Feeding Study with 2-chloro-N-6(4-methoxy-6-methyl-1,3,5- triazin-2- yl)aminocarbonylbenzenesulfonamide (INW– 4189) in Rats. E.I. du Pont de Nemours & Company, Haskell Laboratory Report No. 557–81, November 13, 1981. MRID 0086003. Unpublished. (interstitial cell tumors present)
NOTE: The Wood study was repeated and replaced by the following study (with no tumors):
Mylchreest, E. (2005b) Chlorsulfuron (DPX-W4189) Technical: Multigeneration Reproduction Study in Rats. Laboratory Project ID: DuPont-13475. E.I. du Pont de Nemours and Company, Wilmington, Delaware 19898, U. S. A.
[4] Dupont Telar Herbicide Safety Data Sheet refers to 3 animal studies:
Schneider, P.W., Jr., Smith, L.W., Barnes, J.R., et al. 1980. Six-Month Feeding Study in Dogs with 2-Chloro-N-o(4-methoxy-6-methy-1,3,5-triazin–2yl)amino carbonyl benzenesulfonamide (INW–4189): Report No. 108–80. Final rept. (Unpublished study including pathology report no. 53–79, received Jun 16, 1980 under 352–EX–105; submitted by E.I. du Pont de Nemours & Co., Wilmington, DE; CDL:099461–A). (4 female 4 male dogs were studied)
Wood, C.K., Wollenberg, E.J., Turner,D.T., et al. 1981a. Long-Term Feeding Study with 2-chloro-N-6(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonylbenzenesulfonamide (INW–4189) in Rats. E.I. du Pont de Nemours &Company, Haskell Laboratory Report No.557–81, November 13, 1981. MRID 0086003. Unpublished. (80 rats were studied)
Wood, C.K., Wollenberg, E.J., Turner, D.T., et al. 1981b. Long-Term Feeding Study with INW–4189 in Mice. E.I. du Pont de Nemours & Company, Haskell Laboratory Report No. 836–81, December 28, 1981. MRID 0090030. Unpublished.
LD50: Content only available in Russian. Not possible to verify. Rakitsky, V.N. and Beloyedova, N.S. 2009. Toxicity and Hazardousness of Sulfonylurea Herbicides. Toxicology Herald.
[5] The NZ application was for Agronica Chlorsulfuron Herbicide, a water dispersible granule containing 750 g/kg chlorsulfuron. ‘The substance will be used for the control of broadleaf weeds in wheat, barley and oats’. To be diluted before application to a concentration of 20 g in a minimum of 60 litres of water per hectare with a non-ionic surfactant. The application rate was set at 15 g ai /ha in cereals, once per season.
[6] a. Glyphosate suppresses the antagonistic effect of Enterococcus spp. on Clostridium botulinum. Krüger M1, Shehata AA, Schrödl W, Rodloff A. Anaerobe. 2013 Apr;20:74-8. doi: 10.1016/j.anaerobe.2013.01.005. Epub 2013 Feb 6.
b. Krüger M, et al. (2013) Field Investigations of Glyphosate in Urine of Danish Dairy Cows. J Environ Anal Toxicol 3: 186.
[7] Cleancrop™ Brassica System: The development of herbicide resistant brassica crops for New Zealand farming systems A. DUMBLETON1 , S. GOWERS2 , A. CONNER3 , M. CHRISTIE4 , P. KENNY1 , H. MULCOCK1 , and B. CHARTERIS1 1 PGG Wrightson Seeds Limited, PO Box 175, Lincoln 2 The New Zealand Institute for Plant and Food Research Limited, Private Bag 4704, Christchurch 3 AgResearch Ltd, Grasslands Research Centre, Private Bag 11008, Palmerston North
[8] WHO classification: Genetically modified organisms (GMOs) can be defined as organisms (i.e. plants, animals or microorganisms) in which the genetic material (DNA) has been altered in a way that does not occur naturally by mating and/or natural recombination. The technology is often called “modern biotechnology” or “gene technology”, sometimes also “recombinant DNA technology” or “genetic engineering”.

European Commission: In recent times, it has become possible to modify the genetic make-up of living cells and organisms using techniques of modern biotechnology called gene technology. The genetic material is modified artificially to give it a new property (e.g. a plant’s resistance to a disease, insect or drought, a plant’s tolerance to a herbicide, improving a food’s quality or nutritional value, increased yield).

Such organisms are called “genetically modified organisms” (GMOs). Food and feed which contain or consist of such GMOs, or are produced from GMOs, are called “genetically modified (GM) food or feed”.

[9] A long-term toxicology study on pigs fed a mixed GM diet. Adverse effects of GM crops found. By Dr. Judy Carman 11 June 2013

Leave a Reply