Photoperiod: a topic to shed light on!

For photoperiodism we mean a set of reactions organisms exhibit when periods of light and darkness vary. This phenomenon has an enormous biological importance, because it influences the morphology, physiology, ethology and ecology of living beings.

The photoperiod is the duration at the exposure of light in 24 hours.

To understand how the photoperiod can influence the production of dairy cows, it is necessary to project their application in the right context.

At present the necessary work for the dairy farm management seems to require much more attention to the indispensable technological instruments for the activity: it is now known that the expert eye of the farmer is no longer sufficient to manage the farm .
The difference in an activity with a positive balance or a lot of wasted effort, derives from the correct interpretation of the information collected by the technology supporting the farming.
Interviewing the expert sector technicians and taking the above information into consideration, it seems that there is still space to improve the productivity of our own cows.
Besides genetics operating on the single productivity, it is necessary to intervene on the quality of the herd management in order to guarantee continuity in production.

From the elaboration of official data collected on the entire patrimony of Italian dairy cows, a recurring problem seems to emerge in the autumn months; especially October is characterized by a drastic drop in production estimated at 2.4 kg of less milk than in April by considering the same average lactation days and generally the same environmental temperatures.


Elaboration Ruminantia® on AIA studyng source


This decline has been called “Low Autumn Milk Production Syndrome”. Although the causes are of different nature and to be researched through a complex holistic approach, but three certainly relevant factors are relevant:


Elaboration Ruminantia®


The resolution of the problem, as already said, is not to be identified in one direction only, but with a real 360-degree approach; however, manipulating the photoperiod could be a way to mitigate its effects.

There is a proven correlation between the trend of annual milk production and the solar declination period, better known as the summer solstice and winter solstice, which respectively represent the longest and shortest day of the year.

This relationship is further confirmed by observing the data from farms located in the southern hemisphere, where the same trend in production is highlighted, but reversed, just like the seasons.


Elaboration Ruminantia® on data Dairyaustralia, Dcanz e Usda


Similarly, the predisposition to calving also seems to align with the period of the shorter days, showing a further link between exposure to light in 24 hours and the behavior of the cow.
It is scientifically proven that the light stimulus through the optic nerve reaches the hypothalamus influencing the “secretion” of GnRH, which in turn modulates the pituitary production of hormones, including melatonin. Melatonin in synthesis is the pituitary hormone responsible for the body’s circadian rhythm (24 hours); it is produced during the dark and serves for the “reorganization” of metabolism and hormones.


Elaboration Ruminantia®


Through the manipulation of the photoperiod, therefore the duration of exposure to light of lactating cows, it is reliable to obtain benefits on production, milk, fertility, growth, and efficiency of the immune system.

The management of the photoperiod is possible by installing an intelligent lighting system, able to guarantee a certain and constant light intensity for 16/18 hours a day, 365 days a year (defined as “long day”).

The use of the “long day” is functional for lactating cows and the results can be observed after 3/4 weeks of exposure, taking care to ensure at least 6 hours a day of low light to allow them to rest properly.

Otherwise, dry cows benefit from implementing the “short day” by limiting the hours of daylight to 8 hours per day, showing results during the subsequent lactation, but difficult to implement due to the impossibility of permanent confinement.

The result to be achieved is to increase lactation, for the greater possibility of the cattle to feed over time, but above all by obtaining a better management of fertility distributed over the whole year, thus avoiding the crowding of cows placed in dry conditions during stressful periods in summer, and the consequent loss of production in subsequent lactations.

In conclusion, the management of the photoperiod, is a tool which current technology can be be available to the farmer, and if properly used, it can improve the conditions of the farm and make the production more efficient.


To learn about photoperiod solutions proposed by Coolibrì read the post at the following link.


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