Do Farm Animals Get S.A.D.?

I have never seen literature concerning correlations between psychology and light exposure in animals.

Thus, in simple terms, there is a hormonal shift in animals due to light effects.

But there is a strong correlation between daylight and breeding. Daylight effects melatonin production in the pineal gland, which in turn controls estrus and breeding behavior through interaction with gonadotropin-releasing hormone production via the hypothalamus. This in turn acts on pituitary. Thus, in simple terms, there is a hormonal shift in animals due to light effects.

Some animals are short-day breeders and mate in the winter and others are long-day breeders that mate in the winter. Sheep are short-day and mating in the winter (given their gestation length of around five months) gives them lambs when the weather is fair. Horses have a gestation period of nearly a year, so breeding during fair weather gives them foals during fair weather.

So seasonal hormone shifts occur at different times of the year under different lighting conditions for different animals; melatonin can have different regulatory effects in different species. Light exposure is also important in the poultry and egg laying industry as light intensity and length can effect growth and reproductive performance. Light also has an impact in reproductive performance in sows.

I’m not sure we can call an animal sad.

I’m not sure we can call an animal sad, and I don’t know if there’s an aspect of depression, but we can say that light/daylight can affect hormonal balance in an animal.

Whether being in heat is experienced as a positive or negative for the animal is hard to say. Though they do seem to enjoy mating when in heat.

In short, I don’t know of seasonal affective disorder in animals and since they don’t speak to us, we can’t really talk “scientifically” about subjective feelings of happy or sad.

We can see behavioral differences, however. How the animal experiences such differences emotionally is not readily interpreted.

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