1. Reproductive Hormones Copyright 2010. PEER.tamu.edu

2.  A hormone is a chemical released into the blood and transported to affect cells in other parts of the body.  Hormones regulate many things in the body, such as:  Growth and development.  Male and female sexual development.  How the body uses energy.  Levels of salts and sugars in the blood.  The amount (volume) of fluid in the body. Charolais Cattle

3.  Certain hormones play key roles in reproduction.  They cause different sexual characteristics in males and females and control fertility or the ability to have offspring.  There are several reproductive hormones but the two major ones are Estrogen and Testosterone.

4.  Puberty is the process of physical changes by which a animal’s body becomes an adult body capable of reproduction.  Puberty is initiated by hormone signals from the brain via the pituitary gland to the ovaries of the females and testes of the males. In response, these organs produce a variety of hormones that stimulate the growth, function, or transformation of brain, bones, muscle, skin, mammary glands, and reproductive organs. A mature wild stallion and a young male colt

5. Boer Goat Quarter HorseDuroc Pig

6.  Estrogens are hormones found in females and in low levels in males.  These hormones control different stages of the reproductive cycle in females.  In females, estrogens control the development of secondary sex characteristics.  In males and females estrogen promotes normal bone development.  In females, estrogen is produced by the ovaries. A Jersey cow showing definite female secondary sex characteristics including udder (mammary glands), light muscling in neck and hindquarters, and smaller and more delicate head and jowls.

8.  Testosterone, like estrogen, is also a steroid hormone. It is found in males and in smaller amounts in females.  Testosterone in males is produced by the testicles. A Grand Champion Romney ram

9.  In males, testosterone controls the development of male reproductive organs and secondary sex characteristics such as increased muscle mass.  Testosterone is important in bone mass development as well as the prevention of osteoporosis  Testosterone is also responsible for the libido or sex drive of the male. Welsh Cob

10. Compare and contrast the characteristics of these male animals to the females you observed earlier.