Welcome
Agriculture is an important business throughout the world. This webpage is here to help those get a head start in understanding the digestive systems, nutrient requirements, and reproduction for a few of the animals in agriculture. Animals included are beef cattle, dairy cattle, sheep and goats, and swine.
Introduction to the Digestive System
Agricultural animals' digestive systems work in a few different ways. Within this website two types of digestive systems will be discussed, ruminants and non-ruminants. Ruminants are those animals with a complex four compartment stomach, including cattle, sheep, and goats. The four compartments are called the rumen, reticulum, omasum, and abomasum. The process of digestion for ruminants will be discussed more in depth on the beef cattle page. Non-ruminants have a much simpler stomach, consisting of one compartment. Swine are a type of non-ruminant, which will be discussed in more detail on the swine page.
Introduction to Nutrients
![6 Basic Nutrients Picture](/uploads/5/6/7/3/56734417/8427120_orig.jpg)
There are six basic classes of nutrients, which include water, carbohydrates, fats, proteins, minerals, and vitamins (Figure 1).
- Water is the number one most important nutrient for all animals. Fresh, clean water should be available at all times.
- Energy provides the body with the ability to do work. Work includes digestion, lactation, reproduction, and movement. Fats and oils are another form of energy, but they make up a smaller portion of the diet.
- Fats increase energy density in the diet because of the high calories per unit of weight than carbohydrates and sugars.
- Protein is a main building block of the body and is measured as % Crude Protein (CP). It is an important component of muscle, the nervous system, and connective tissue. Composed of amino acids, proteins are essential for maintenance, growth, lactation, and reproduction.
- Minerals are required for a number of body functions including, growth, bone formation, and reproduction. Macro minerals are those minerals required in larger amounts including sodium, calcium, phosphorus, magnesium, and potassium. Those minerals required in smaller amounts are called micro or trace minerals and include iodine, copper, zinc, sulfur, and selenium. Poor growth is a common symptom seen with mineral deficiencies.
- Vitamins are biological compounds active in small amounts. Vitamins A, D and E are a few of the necessary vitamins needed in an animals life. These are normally found in fresh forages. Vitamin A is required for normal growth, reproduction, and maintenance. Vitamin D aids in proper development of bone. Vitamin E is important for development of muscle tissue.
Introduction to the Reproductive System
![Reproductive System Picture of Female Cow](/uploads/5/6/7/3/56734417/6635604.gif?309)
Reproduction is an important process in agriculture. If an animal is not producing good offspring, then profits from that animal will be low. Male and female reproductive anatomy is all roughly the same for each animal. Reproductive differences will be discussed for the beef cow and dairy cow, sheep and goats, and swine. First, let's discuss the anatomy of the female and male reproductive systems.
- Female reproduction starts with the ovaries. There are two ovaries which produce ova (eggs) as well as the female sex hormones estrogen and progesterone. Follicles are precursors to ova and develop in the ovary. Primary follicle turns into secondary follicle which in turn becomes the tertiary follicle. The tertiary follicle becomes the dominant follicle which finally matures into the Graafian follicle which ruptures to release the ova. The point of rupture leaves a scar called the "corpus luteum." The infundibulum directs the ova to the oviduct (fallopian tube). The fallopian tube is the site of fertilization. Cilia line the fallopian tube to help propel the ova toward the uterus. The uterus takes on a variety of shapes between species. At the posterior end of the uterus is the cervix, lined with mucosal cells which aid the sperm in moving into the uterus for fertilization. During gestation the mucous from the cervix hardens to form a non-penetrable seal between the uterus and vagina. The vagina has three functions: female organ of copulation at mating, birth canal during parturition, and serves as an exit passage for urine. The vulva is the end of the line and serves as the exit to the environment.
![Reproductive system picture of Bull](/uploads/5/6/7/3/56734417/4337704.jpg?250)
- Male reproduction starts with the testicles which are responsible for the production of sperm cells, and the hormone testoterone. Sperm cells are produced in the seminiferous tubules within the testicles. The sperm cells are then stored in the epididymis, where they mature. Over time sperm degenerate, but are absorbed by the body and replaced by younger sperm. The testicles are housed in a two lobed sack called the scrotum. The scrotum has the primary function of controlling temperature of the testicles. To do this, the muscle tunica dartose contracts or relaxes to move the testicles closer or farther from the body, respectively. The vas deferens deliver the sprem from the epididymis to the urethra. The urethra is responsible for final delivery of the semen (sperm plus other fluids) that extends from the bladder through the penis. .
- Parturition is the act of giving birth. It includes three stages: first stage starts parturition by softening and dilating the cervix and the start of uterine contractions. Stage two is the expulsion of the fetus. Stage three is the expulsion of the placenta. The length of each stage of parturition is different between species. Dystocia is prolonged and difficult birth and is seen occasionally in the agricultural field. Reasons for dystocia to occur can be from an over-sized fetus, small pelvic area, abnormal fetal presentation in the body, or a combination of all of these.
Created by: Michelle Connelly July 31, 2015.