* Rat study to see if glyphosate affects reproduction
* Italian scientist expects full results by June
* Weedkiller is centre of row over whether it causes cancer
* EU must decide this year whether to re-licence or ban it
By Kate Kelland, Health and Science Correspondent
LONDON, April 13 (Reuters) - Results of a new animal study into possible health risks of the weedkiller glyphosate will be published in time to inform a key EU re-licensing vote due by the end of 2017, according to the researcher leading the trial.
A row over possible effects of glyphosate - an ingredient in Monsanto's big-selling herbicide Roundup - has prompted investigations by congressional committees in the United States and forced a delay in Europe to a decision on whether it should be banned or re-licensed for sale.
Giving details and preliminary findings of the latest study to Reuters, Italian scientist Fiorella Belpoggi said experimental rats exposed to the herbicide at levels equivalent to those allowed in humans showed no initial adverse reaction.
"Exposed animals had no evident differences from non-exposed animals," Belpoggi, who is director of the Cesare Maltoni Cancer Research Centre at the Ramazzini Institute in Italy, said in a telephone interview.
"But this tells us very little at the moment, because the examinations of key parameters that could be affected by exposure are still being done (and) we are waiting for those results," Belpoggi added.
Those parameters include any genetic changes, as well as potential toxic effects on measures related to fertility, such as sperm, embryo development and offspring growth, she said.
Argument over glyphosate centres on whether it is carcinogenic. Scientists at the International Agency for Research on Cancer (IARC) say it probably does cause cancer, putting them at odds with scientists at the European Food Safety Authority, the U.S. Environmental Protection Agency and multiple other safety and regulatory agencies around the world, who say it likely doesn't.
Congressional committees in the United States have raised questions about the work and funding of IARC, which is based in Lyon, France, and the Ramazzini Institute, based in Bologna.
IARC and Ramazzini defend the independence of their work and say their research is conducted to the highest scientific standards.
A spokesman for Monsanto said: "There are nearly a thousand scientific studies from decades of research that are already available to every regulatory agency in the world, which have all concluded that glyphosate is safe to use."
According to data published by IARC, glyphosate was registered in more than 130 countries as of 2010 and is one of the most heavily used weedkillers in the world. Analysts have estimated Monsanto could lose out on up to $100 million of sales if glyphosate were banned in Europe.
Belpoggi said her team decided to conduct their trial to produce fresh, independent results in an effort to settle differences over glyphosate's health effect.
But she stressed that due to time constraints, the study is not able to analyse the weed killer's potential carcinogenicity, which would take several years to research properly, given the time any tumours might take to develop and grow.
"We are focused on reproductive and developmental issues, in other words, whether glyphosate ... affects the development of embryos, foetuses and pups," she said.
Chemicals that can affect hormones and reproduction are known as endocrine disruptors and, like carcinogens, are subject to strict regulations in the European Union.
This study involves scientists working at five laboratories, Belpoggi's and one other in Italy, and three outside the country. "This was to ensure we would have the best experts analyse each end point," Belpoggi said. The study is funded by the Ramazzini Institute, a research cooperative of around 28,000 members who are its co-owners and raise funds for its work.
Using laboratory rodents known as Sprague Dawley rats, the researchers exposed them to low levels of glyphosate and its formulation Roundup in their diet, equivalent to U.S. Acceptable Daily Intake (ADI) levels permitted in humans.
The U.S. ADI for glyphosate is 1.75 milligrams per kilogram of body weight per day while the European Union ADI for consumers is 0.5 milligrams per kilogram of body weight.
Full results should be available by June, Belpoggi said, and will be submitted in a paper for peer review and publication in a scientific journal. A draft copy of the results will be sent at the same time to the European Commission.
The Commission has said it expects to restart talks with EU member states by August on re-approving the use of glyphosate in herbicides. A decision is due before the end of 2017.
"We would like to have the results in time to help regulators have a good judgment about this chemical," Belpoggi said. "If it is negative (no effect), then I will be happy because I am also exposed. But if there is some damage, then we would like everyone to know."
Editing by David Holmes