After 18 months of research in to phytoestrogens and their impacts in sheep at the University of Western Australia's Institute of Agriculture, the results show that it was not just ewes being affected.
Lefroy Fellow Kelsey Pool, WA, found that after testing ram semen with very small amounts of phytoestrogens, which was tenfold lower of what was predicted to be able to reach the seminal plasma, there was a detrimental reduction in sperm function.
Dr Pool explained that phytoestrogens (plant-based compounds that mimic estrogen in the body) had been previously reported to be disrupting reproduction and having detrimental impacts.
Reported signs of exposure in the past were a disruption in ovulation, changes in uterine growth and function, morphological changes to the reproductive tract, more rapid puberty onset, crosses in placentas, and reduction in sperm function and production.
Some of the common signs from exposure to the phytoestrogens were disruption in ovulation, changes in uterine growth and function, morphological changes to the reproductive tract, more rapid puberty onset, crosses in placentas', and reduction in sperm function and production.
"Some of the first studies that phytoestrogens could impact reproduction were performed in Western Australia with ewes eating clover based pastures actually became infertile," Dr Pool said.
She said this was more commonly known as ovine clover disease, which led to abortion, still births, and uterine prolapses in ewes.
"While sub clovers are still in our production system, these events do not occur as often due to general improvements with agricultural production, we are breeding more strategically and have much better nutrition, and have moved forward in genetic gain."
"What has likely persisted is sub fertility, things like losses or reductions in lambing or joining rates that can't be explained with environmental factors or ewes that get less fertile with age."
"There are decades of research saying ovine clover disease was purely a ewe oriented issue, we have presented the first evidence that this disease also effects the ram," she said.
Dr Pool found that after testing ram semen with phytoestrogens in the lab, which was tenfold of what they would experience in a common environment, there was a detrimental impacts.
There was a loss in motility, the sperm increased in membrane fluidity at the wrong times of development, and there was a high generation of mitochondrial superoxide production (generated by electrons leaking from the electron transfer system).
After several hours, the sperms DNA integrity was lost and began to fragment.
"Theoretically, these cells, after exposure to minute amounts of the equol are less likely to be navigate the female tract, less likely to be able to fertilise the oocyte, and less likely to develop into a successful pregnancy, should they make it that far," Dr Pool said.
After conducting paddock tests exposing different groups of rams to the sub clovers, Dr Pool said there was no real difference in the sperm motility between the ram groups and the control rams after they were taken out of the paddock.
What was seen however was an increase in abnormal sperm and DNA fragmentation after five weeks of grazing the sub clover.
Looking further in to the long term effects, Dr Pool conducted research using fruit flies and after a simple breeding model, she said the dietary phytoestrogens decreased the reproductive capacity of the exposed individuals and their decedents across two generations.
"Both maternal and parental exposure causes a comparative reduction in seminal vesicle size in the subsequent F1 (child) generations, whilst effects are only seen in F2 (grandchild) progeny from an exposed F1 female," Dr Pool said.
"Are these pastures actually safe for rams? It depends. If they are not actively grazing the clovers close to or in joining, then you are likely ok, we have seen there aren't any long term effects on reproduction. If you are making out of season ram use, particularly for stud breeders or semen collection for cryopreservation, then I would certainly avoid these pastures," Dr Pool said.
The detailed results from this research were presented by Dr Pool during a Lefroy Fellow research seminar on May 11.
Dr Pool then presented how a neurohormone could change the physiology of twin lambs, and how the information could be used to improve lamb production.
She explained that twin-born lambs have a 30 per cent mortality rate in the first 72 hours of life and when compared to single born counterparts, they are more likely to experience hypoxia, traumatic or injurious births, lower birth weight and less brown fat around organs, mismothering, prone to dealth by exposure, potentially left with a life-long impairment of cognitive function.
One solution Dr Pool said had been "thrown around" was melatonin.
In sheep, melatonin is important for reproductive process, controls reproductive onset, is a potent antioxidant, promotes vascular growth, and is a neuroprotectant.
"The pro for sheep production is that melatonin is already readily available in the market, slow release melatonin tablets are already on the market and we started to see animals treated with the implants had better reproduction, higher pregnancy rates, could upregulate ram production," Dr Pool said.
"We decided to see if we could use these slow release implants to improve twin lamb production and welfare by treating the lambs before they were even born."
The research involved a large trial of two flocks of 150 ewes on different properties with ewes categorised four ways by the control, treated in early pregnancy, treated in late pregnancy, and then treated in both early and late pregnancy with the slow release melatonin capsules.
These groups of 150 ewes was of particular importance as it was the standard size for a flock of twin pregnancy ewes.
Dr Pool said she found that exposing the lambs to melatonin in late pregnancy increased the amount of brown fat and body weight while low doses increased vascular growth but too much reduced it.
"The main take away from the research was that melatonin was having a physiological response," she said.
Dr Pool said the late gestational exposure to melatonin increased lamb brain mass and hoping to see a correlation between the mass and cognitive function, the lambs were rested using a maze tests and novel object test.
"In my opinion, these are some of the most interesting results," Dr Pool said.
"All the melatonin exposed group performed better in the cognitive tests. Exposure to melatonin makes these animals more inquisitive and want to interact with objects," she said.
"Then we thought, could melatonin exposure alter lamb-dam communication?"
Dr Pool said the majority of the melatonin groups were more vocal than the control counterparts in both the maze and novel object.
Dr Pool said in summary the lambs exposed to melatonin in utero had increased weight and brown fat in the autopsied population, subtle increases in marking and weaning percentages, and weight gain, superior learning ability, increased vocalisation, and were more inquisitive or bolder.
"From both, the events that happen in utero or early life drive production outcomes and drive how they navigate life in to future years," Dr Pool said.
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