Older horses Part 5: Hormone management of the horse

Sex hormones in the horse 

A mare becomes stallion, or fertile. During the stallion phase, the hormone that dominates is estrogen. Not only estrogen plays a role in the fertility of mares, but several hormones play a role during the cycle. A mare becomes stallion approximately every three weeks. The fertility of mares is seasonal. As the days get longer, more Gonadotropic Releasing Hormone (GnRH) is released. GnRH then takes care of the production of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), with possible coverage, progesterone (pregnancy hormone) is still produced. When a mare is stored in a warm but especially light stable, it can also become stallion in the winter. With these different hormone peaks and troughs it is therefore not surprising that this can affect the state of mind of a mare. A stallion makes testosterone. Stallions that are neutered undergo a change in their hormone balance. Castration eliminates the testosterone production of the horse. Testosterone is responsible for the development of typical body characteristics / exterior of a stallion such as a large muscular neck and a more generous muscular body. Testosterone is also the cause of the typical stallion behavior such as dominance, biting, breeding behavior and being distracted in the presence of mares. After castration, the behavior of the horse, now a gelding, becomes more constant and calm. A gelding is not fertile and due to the reduced testosterone production it is more predisposed to obesity.

Hormones are responsible for many processes 

Thus, shedding also occurs under the influence of hormones, this hormone is made in the pituitary gland and also causes a horse to build up fat reserves for the winter. When a change in day length is registered in the brain, the process is initiated. The horse's thyroid gland produces various hormones that have functions in metabolism, blood pressure, heart rhythm and digestion. Blood sugar levels are also kept constant by hormones, namely insulin and glucagon, these hormones are made in the pancreas.

During a shock reaction and during stress, the hormones’ adrenaline, noradrenaline and cortisol are released into the body, these hormones are made in the adrenal glands. Adrenaline causes the heartbeat and breathing to accelerate, the pupils become larger and the blood supply is moved from the digestive system to muscles. So there are many organs that produce hormones and many processes that are under the influence of hormones.

Hormone management in older horses

Mares do not have, like people, a transition or menopause. They can become infertile due to old age, this can be caused by an outdated uterus or ovaries. Other horse diseases that are caused by a disruption in hormone balance are:

• PPID (Cushing)
• Insulin resistance (IR)
• Equine metabolic syndrome (EMS)

Supporting old horses with herbs in the event of a disturbed hormone balance 

To support the horse it is important to keep a horse at a healthy weight, both being underweight and overweight must be avoided. In addition, there are herbs that can support horses, such as with cushing. The Hartog 5 * Complete Care Senior contains a herbal blend specially tailored to the old horse. The composition of the herbal blend helps the horse to regulate hormone balance, among other things. Thanks to the added herbs, the Hartog 5 * Complete Care Senior is not only a complete feed in the field of fibers, vitamins and minerals, but also contains a supplement.

The next article ‘Part 6’ is about diseases due to changes in the hormone balance