Pesticides & NZ Herd Fertility. Is it worth asking a few questions?

There appears to be a reluctance somewhat in the mainstream agricultural press ( a few smaller independents may differ) to investigate the potential health outcomes of pesticides and chemicals on stockfeed.

A few years ago an empties rate of 10% would have been shocking – a profound blow. However now state that the average empties rate in New Zealand is now 13%.  And if looking at the top performers, the top 25% of farmers, they achieve an empties rate of 10% based on 2011 figures. 6 Weeks put forward an industry target of 6%.

These figures are New Zealand based, but there is fertility decline internationally. list eight key management areas that affect herd reproductive performance:

1. Calving pattern;  2. Heifer management; 3. Body condition and nutrition; 4. Heat detection; 5. Dealing with non-cyclers;  6. Genetics and artificial breeding practices;  7. Bull management;  8. Cow health.

Kiwi farmers are just as smart as they have always been.  And it's commonly known that if you breed for performance, fertility often suffers - what's known as negative genetic correlations between milk production and reproduction. That is a big one, and it's very difficult to tinker with nature and keep all the 'best bits in'. 

However farmers don’t necessarily have control over quality of inputs – feed quality.

I believe that government authorities and farmer representative organisations haven’t even started to take into account the quality of feed our dairy cows and bulls are exposed to – in particular feed with higher loading of pesticides. Anecdotal reports indicate fertility may be higher for cows raised organically. While that may not be an option, keeping feed as chemical free as possible may be worth consideration. 

NZ doesn’t have maximum residue levels for pesticides on feed, not does it test and monitor our stockfeed.

For over 15 years meat producers have understood that chemical topping can boost stock growth rates and increase clover dominance.  Beef and Lamb have noted: as long as farmers understand some of the limitations such as fertility, pasture composition and effects of the season.’ 

Scientists and researchers have been aware of glyphosate's negative effect on semen quality since 1995.    [1]  [2] [3]

What is not commonly understood are the effects of cumulative chemical exposure on livestock.

Routes of exposure:

1.       Cleancrop HT™ brassica cultivars (leafy turnip, rape, bulb turnip, swede) that are bred to be tolerant to the sulfonyl urea herbicide, DuPont® Telar, active chemical Chlorsulfuron. (China revoked the registration of chlorsulfuron products as of 31 December 2013 and they will be banned as of December 31, 2015. 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.)

2.       Baleage & silage that has had glyphosate based herbicides (GBH) applied to it.

3.       Pasture spray topped with (for example) GBH or gramoxone (paraquat).

4.       Cereals converted to forage that have been desiccated with Reglone (diquat) or GBH.

5.       Imported GE/GMO feed – most protein meal imported from the USA or South America will be genetically engineered. Over 80% of GE product has a herbicide tolerant trait and will hold higher residues of GBH's. (So therefore French protein meal, for example with less GMO production may be a better bet).

I don’t know if farmers are aware, but vets expect infertility when stock are fed for example, a supplementary diet of HT swedes and herbicide topped baleage.  

Desiccation and spray topping with chemicals is a significant dietary change that has not been properly explored. Scientific literature is now demonstrating that negative effects occur at much lower levels of exposure than previously thought. None of the studies held with any of the big assessment agencies, including NZ EPA consider the effect of the stronger full formulations, commonly applied on feed.

Here are some links that can explain it better than me:

A Danish study recently concluded:

A. Glyphosate can affect the microbial populations (microbiota) in the animal gut with secondary effects on animal production and health

B. Glyphosate can affect animal mineral status with secondary effects on animal production and health

We need farmers to be privy to this discussion. Something mainstream papers in NZ are avoiding. The HT swedes story in Southland is evidence of media shutting up and farmers not hearing the full story.

We need an open discussion within academia. We don’t need discussion to be stifled because corporations don’t want us to engage because their turnover might be impacted.

Feed input quality can only be a part of the story of declining fertility - but it is important to consider it and put money towards research (without financial connections to the corporations that sell the stuff). It’s about productivity. It’s about money. It's about the mix to maximise production and fertility.

As farmers don’t have time to search for information – here are some sites and papers that may be useful.

1. Dr Krüger:

a) Presentation: Collateral damages of the herbicide glyphosate in dairy cows, current possibilities to neutralize this contamination. Monika Krüger (Prof. em.) & Awad Shehata Institute of Bacteriology and Mycology of Veterinary Faculty, University of Leipzig. [4]

b) Glyphosate Increases Birth Defects in Piglets  [5]

d) The Cattle Site – News Further Investigation Needed on the Effect of Glyphosate on Livestock Health.

2. Ib Peterson, a Danish pig farmer, was an early farmer to speak up about stock response to GM animal feed. (Over 80% of GM feed has higher residues of glyphosate based herbicides.)

The Ecologist. Deformities, sickness & livestock deaths: the real cost of glyphosate & GM animal feed? Andrew Wasley. November 2013.

3. Interviews at the China conference on GMOs 2014.

Ib Peterson.    Interview 1.     Interview 2. 

Art Dunham, veterinarian on GMOs and harm to animals 

Howard Vlieger, Farmer and Soil Specialist  

3. Evidence of GMO harm in pig study

4. Other

Healthy Gut Flora: Key to health. Article on how glyphosate can affect ruminant health.

Dr Don Huber : GMO crop pathogen and infertility.

Original letter – Dr Don Huber to the head of the US Dept. Agriculture.

Review by researchers at the University of Adelaide, Flinders University and the Institute of Health and Environmental Research: Not enough evidence that GM crops are safe to eat.

Stuff NZ. No quick answers to stock death mystery

10 Reasons we don’t need GM foods. by Claire Robinson, MPhil, Michael Antoniou, PhD, and John Fagan, PhD

Syngenta Charged for Covering up Livestock Deaths from GM Corn. Sustainable Pulse.

German Poultry Industry Giant Returns to GMO-Free Production



[1] ISIS report. Glyphosate/Roundup & Human Male Infertility

[2]  An acute exposure to glyphosate-based herbicide alters aromatase levels in testis and sperm nuclear quality.  Estelle Cassault-Meyer, Steeve Gress, Gilles-Éric Séralini, Isabelle Galeraud-Denis.  Environmental Toxicology and Pharmacology
Volume 38, Issue 1, July 2014, pp. 131–140

[3] The skinny on Roundup sex and sperm - the studies not held with the US EPA, NZ EPA, WHO and EU.

[4]  Visceral botulism at dairy farms in Schleswig Holstein, Germany - Prevalence of Clostridium botulinum in feces of cows, in animal feeds, in feces of the farmers, and in house dust.  Monika Krüger, Anke Große-Herrenthey, Wieland Schrödl, Achim Gerlach, Arne Rodlof. Anaerobe. 2012 Apr;18(2):221-3. doi: 10.1016/j.anaerobe.2011.12.013. Epub 2011 Dec 21. 

Krüger M, Shehata AA, Schrödl W, Rodloff A. 2013. Glyphosate suppresses the antagonistic effect of Enterococcus spp. on Clostridium botulinum. Anaerobe. 20:74-8. doi: 10.1016/j.anaerobe.2013.01.005. Epub 2013 Feb 6.

Krüger M, Schrödl W, Neuhaus J, Shehata AA (2013) Field Investigations of Glyphosate in Urine of Danish Dairy Cows. J Environ Anal Toxicol 3: 186. doi:10.4172/2161-0525.1000186

[5] Krüger M, Schrödl W, Pedersen Ib, Shehata AA (2014) Detection of glyphosate in malformed piglets. J Environ Anal Toxicol 4: 230. doi:10.4172/2161-0525.1000230


Zdziarski IM, Edwards JW, Carman JA, Haynes JI.  GM crops and the digestive tract: A critical review, Environment International (2014), http://dx.doi/10.1016/j.envint.2014.08.018

Dr Santadino: Glyphosate Destroys Earthworm Eisenia fetida Populations