The impact of hormones on moulting

Birding is a relatively eco-friendly activity, but the newly proposed (animal transport) restrictions to prevent the spread of viruses threaten to throw a spanner in the works. With fairness, a practical solution could still be found to this.

The viruses have been living on this planet for 200 million years -i.e. much longer than us- and they don't just let themselves get pushed around...

So yes, the fancier has, in fact, the better profile for not pushing the habitat over much.

He enjoys being at home with his birds a lot. Besides performing well, he usually aspires to do much fewer material things that burden the environment. Still, instead, he relishes in amazement the magical capacities of his birds, which fills him with emotion.

For some time, I have been asked to explain the influence of hormones on the moult. On this exceptionally complex event, science is in unanimous agreement: namely, that they do not know the finer details. It is one of the most mysterious physiological phenomena that remains largely unexplained.The fact is that whoever handles it well as an aficionado can make a difference. 

Regarding moulting, we do not provide schemes here, which can be read in thousands of writings anyway, but instead, the links between this phenomenon with several variables.

Some theories say hypotheses, exist because none of them is entirely conclusive. Many faculties have researched the influence of glands and all the hormones they produce, including the pineal gland or hypothalamus, which weighs only a few milligrams and is an important player.

This gland functions like a light switch, primarily regulating the day and night (light and dark) rhythm, with a pronounced influence on moulting, which is related to body temperature.

For instance, body temperature appears higher in light than in darkness. Removing this hypothalamus increases the temperature in both light and dark. It also controls other glands that, in turn, produce their hormones with particular properties, such as the pituitary gland (prolactin) but mainly the thyroid gland (thyrotropic hormone, responsible, among other things, for the development of the follicles of the new feathers). Secretion is subject to seasonal variations as a function of moulting, and it has been observed that this coincides with the build-up of fat stores, which in turn affects the entire metabolism.

Fat is fuel for generating heat and energy when flying or feeding the young. A logical connection between moulting, egg laying and breeding is at play here. Indeed, we observe that moulting during the last days of breeding is inhibited by prolactin (a hormone secreted by the pituitary gland) responsible for crop milk production.

Logically, the system chooses the process that provides the energy needed when feeding the young that is in charge of keeping the body warm during the moult.

The adrenal gland also plays a role in moulting. It produces the cortisone hormone, whose blood levels rise during darkness. Long periods of light do not affect the blood levels of cortisone.

Medicating naturally delays moulting and can also push the pain threshold. Corticosteroids stimulate fat deposits.

Their use during exhibitions as a moulting inhibitor and condition promoter was once widespread, hence now strictly forbidden. All the glands mentioned above and hormones also interfere with the enormously complex immune system, which is scattered throughout the body and responsible for defending against harmful invaders.

We have Fabricius' purse, thymus gland, spleen, tonsils, the Harder gland, bone marrow etc., all of which can produce cells (granulocytes, lymphocytes, macrophages etc.). In the blood and egg yolk, particular proteins (immunoglobulins) also have a significant role in the immune system.

It is also known that stimulating this system (e.g. vaccination) can have a direct and not insignificant effect on moulting and performance.

The impact of short-term and long-term stress affects the functioning of the autonomic nervous system (parasympathetic), which provides action ( through adrenaline) and recovery (acetylcholine). The dual action of the parasympathetic is expressed in English as "fight or flight" on the one hand and "rest and digest" on the other. It concerns the primal instinct of all creatures to survive in the wilderness.

This brief review provides a limited summary of a hugely complex endocrine (glandular) mechanism.

For example, hormones during reproduction, during which the breeding period affects moulting.

In other words, there are many hormones at play, which, moreover, all work together and with each other like a symphony concerning moulting, fertility, disease defence, energy production, etc... in short, the entire conscious and unconscious behaviour of the bird.

As a scientist, you become impressed, humbled and above all, grateful for the privilege of studying the good functioning of this higher form of life and applying the knowledge gained directly through refining dietary supplements at the service of health, medicine in general and sports performance in particular...

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