Endocrine diseases of Ungulates

In order to survive, animals must constantly adapt to changes in the environment and it is the endocrine system that works to bring about these adaptations. In general, the endocrine system brings about longer-term adaptations by sending out chemical messengers called hormones into the intracellular fluid or the bloodstream. The endocrine system is very influential and relates to most, if not all the other principle systems of the body. It is accountable for the production of hormones as well as the regulation and monitoring of them as well. These hormones function as chemical messengers throughout the body. Through disparate mechanisms, they are able to generate specific responses in target cells or organs.

The hormones secreted by the endocrine system come from a variable range of different places. Amidst those culpable for hormone production are the glands as well as a few organs as well. The primary glands associated mostly with hormone production are the adrenal, pituitary, thyroid, parathyroid and the thymus. The organs, which also perform a substantial role are the kidneys, pancreas, gonads, heart and alternative parts of the digestive tract. The hormones which are regarded of greatest importance for maintenance of the body in ungulates and averting disease are;

• Growth hormone GH

• Luteinizing hormone LH

• Follicle stimulating hormone FSH

• Thyroid stimulating hormone TSH

• Adrenocorticotrophic hormone ACTH

• Anti-diuretic hormone ADH

• Adrenaline

• Noradrenaline

• Aldosterone

• Cortisol

• Insulin

• Glucagon

• Testosterone

• Oestrogen

It is these hormones in which enable the endocrine system in ungulates to promote growth, development, reproduction and behaviour among other traits too. Any deviation away from the regulatory level of these hormones listed above in ungulates will result in specific hormonal diseases to the animal in question. Hypothyroidism is an endocrine disease associated with the thyroid gland. The thyroid gland is located on the ventral side of the trachea on both sides just caudal to the larynx and vary in appearance amongst ungulates. In the horse and cow it consists of two lobes, which are connected by an isthmus. In the horse, each lobe appears more oval in shape in comparison to the cow which takes up a rectangular appearance. In the pig, the thyroid gland is an unpaired compact organ with a granular like presence. The main two hormones relating to the thyroid gland are thyroxine (T4) and triiodothyronine (T3). They are produced by follicular cells before being released into the bloodstream. Hypothyroidism is also referred to as ‘goitre’ and a deficiency in these hormones will result in this endocrine disease, causing the overall well-being of the animal to deteriorate, such examples being, their decreased metabolism of lipids, carbohydrates and proteins, their desire and willingness to exercise and their overall growth.