Constat light induce on long terme frequent escape effect due to circadian internal clock and this escape is directly linked to prolactine relesae or effect (receptivity) but some peripheral mechanisms could remain functionnal as here OT synthesis/release/receptivity that could be stimulated on long term by prolactin. It culd be nice to test milk ejection and OT release bay example. If interrested..do not hesitate to ask me for collaboration !
best regards and Bravo for your nice work.
Pierre-guy
Hi,
No, we have tried to evaluate milk ejection in dark and light during day and night time but had problems with OT sample stability (a freezer broke down) and did not get useful data. In the LED work we will start with testing effects of different wavelength spectras on primarily IGF-1, milk yield and activity (standing/lying).
Thanks for asking!
/Sigrid
There is a methodological challenge in all light studies with the duration of exposure to light before evaluating endocrine responses. Sampling during milking (for OT) requires catheterization and sedatives used for inserting it will probably change endocrinology. We have not found a robust way to do this (duration of light exposure + catheterization without changing responses). Any suggestions are most welcome!
Thanks for the papers and your answer. I worked hard in my young age to setup a protocol for catheter implantation for long term studies in alive and not restrained animals in livestock breeding conditions (ewes, goats and cows, zebu and even camels more recently!). It remain my work to study endocrne response at milking and you are right..it is difficult. I do not know the ethical constraint you have in your country but if you can fit actheter and let animals fitted on One or two weeks, you can sucess for sure (effectively fitting a catheter before measurent is NOT possible if you want to record physiological reaction) : you need to fit catheter (silicon one for human long term usage-I can give you all refe if needed) by using only small knob of anaesthetic cream in the jugular region punctionned. Do not inject with needel intradermally or use intradermal pressure injector for anaesthetic that could soften the vein and make the puncture more difficult and increase the risk of vein wall tearing by the trocard needle. After that, the catheter is rinsed, filled of heparinized solution, maintained and protected by a collar made of different kind of surgical strip of adhesive tapes to maintain the catheter free in the vein but protected against scratching and other animal action. The catheter extremity is equiped with a connector and plugged with a silicon plug. The last rinse of catheter is done via a siringue through the silicon plug to limit at the max the risk of air entry at the catheter extremity. With such a device, the blood have limited possiblity to enter and clot at the internal extremity. Then catheter need to be rinsed at least each two days and i prefered to work each day on the animal to accustom it to the manipulation of opening the bandage , opening the catheter, adding a prologation tube to the collector for verification of blood sampling easiness before a new rinse and final refilling with heparinized solution. The dely between catheter implantation and fist experimental collection of bloodis at least of 4 days (a week is better). With such a system and use of a prolongation catheter, it is possible to work in the back or on the side of animals without perturbation and stress during milking (I have recorded OT releases at milking during 5 months in dairy ewes without any modification of OT release !!)
I don't know how you would assay OT because there is only some lab able to assay OT for ruminants with a good efficiency (Bruckmaier in bern, uvnas moberg in sweden and mine in europe mainly) and kits on the market are totally incapable to assay OT in ruminant blood/serum! In each case, you have to know that blood have to be collected in chilled tubes protected against light and kept plugged in iced water until the end of kinetic of sampling (around 12 min) then immediately centrifugated in a refrigerated centrifigator (4°C max). Serum have to be sampled in other chilled tubes kept on ice without direct lighting by sun and then plugged and frozen immediatly à -20°C until extraction and assay. It is the good way for good sample..
If I can help, do not hesitate to ask me!
regards
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