The reproductive system of farm animals

Reproduction is the biological process that gives rise to new organisms (offspring) from their parent. This includes all the organs and tissues concerned with reproduction in the animal. Reproduction is the ability of animals to give birth to young ones. The purpose of reproduction is to ensure continuity of life. Farm animals reproduce sexually and mostly viviparous (given birth to the life form of their young).

Poultry birds and fishes are oviparous (they both lay eggs and poultry brood over theirs while fishes do not). Fertilization in most farm animals is internal but external in fishes and hormones play an important role in the processes of reproduction as well as in the development of sex-inhibited characters.

Male reproductive system:

The male reproductive system includes the testes, which produce the spermatozoa and sex hormone called testosterone, which aid the development of male secondary sexual characters. The spermatozoa are produced in the testes or testicles by a process called Spermatogenesis. The testes may be suspended (as in cattle, sheep and goat) and are protected by scrotal sac (scrotum) outside the abdominal cavity to enable the sperm cells to be produced at the desired temperature.

The epididymis ensures the storage maturation of sperm cells in the testes, i.e. store sperms until they are matured. The testes are connected to the uterus masculinus by vas deferens which transports sperms from testes to the uterus masculinus where mature spermatozoa are stored until they are released during mating.

Attached to the side of the urethra are accessory glands i.e. Cowper’s gland also called a bulbourethral gland, seminal vesicles and prostate gland which produces slimy alkaline fluid which aids the movement of spermatozoa. The fluid together with spermatozoa results in the formation of semen, the urethra is a urogenital organ which helps to inject sperms into the vaginal as well as the removal of urine. The urethra ends externally in the penis.

The male reproductive system of farm animals

Female reproductive system:

The female reproductive system consists of a pair of ovaries that produce egg cells or ova and fallopian tubes where fertilization occurs and which transport the fertilized ovum to the uterus. The uterus is the place in the female reproductive system where the growth of foetus takes place. The cervix separates the uterus from the vagina or birth canal. The entire system ends with the vulva (labia majora and minora) to the external.

The vagina is a fibromuscular tube of 7.5 to 10cm in length, situated anterior to the rectum and anal canal and posterior to the bladder and urethra. It is the organ of copulation, deposition of semen, and exit from the uterus during parturition. The accessory organ of the female reproductive system includes an outermost portion of the vagina (vestibule). The Cowper’s glands also called Bartholin’s gland is 1.5 to 2.0cm in length located above the perineal gland. It secretes mucus to provide vaginal lubrication.

Theory

1. Describe digestion in a named polygastric animal.
2. Differentiate between monogastric and polygastric animals.
3. What are sphincters? 

REPRODUCTION IN FARM ANIMALS II

CONTENT

• Processes of egg formation in poultry
• Male and female reproductive hormones

PROCESSES OF EGG FORMATION IN POULTRY

The egg in poultry is partly formed in the ovary and in the oviduct. At ovulation the ovum carrying the yolk is released by the ovary into the oviduct through the funnel called infundibulum. Fertilization takes place in the infundibulum where the egg spends 15 minutes and moves into the magnum. In the magnum, part of the egg white (albumen) and the chalaza are secreted round the yolk. The egg stays for 3 hours in the magnum and moves into the isthmus where the two shell membranes are formed. The egg stays for 1 hour 15 minutes in the isthmus and moves into the uterus where it remains for 18 – 21 hours and the egg shell is formed from calcium carbonate. Mineral solutions are also added to the egg before it moves into the vagina whereit remains for 1 – 15 minutes before it is laid through the cloaca. A complete formation of eggs takes almost 26 hours.

REPRODUCTIVE SYSTEM OF POULTRY BIRDS

EVALUATION

• Describe the processes of egg formation in poultry.

• Describe the reproductive system of poultry birds.

MALE AND FEMALE REPRODUCTIVE HORMONES

Hormones are organic chemical substances produced by endocrine (ductless) glands that influence growth, development, and metabolic activities in farm animals. These include:

GENERAL EVALUATION 

• List five animal hormones and their functions.

1. What are the functions of the following in the processes of egg formation in poultry?

• Ovary
• Oviduct
• Magnum
• uterus

WEEKEND ASSIGNMENT

1. Which of these is not a part of the male reproductive system A. uterus masculinus B. oviduct C. testes D. vas deferens
2. The following except one are female reproductive hormones A.oestrogen B. progesterone C. testosterone D. oxytocin
3. Fertilization in poultry birds takes place in the A. infundibulum B. isthmus C.magnum D. uterus
4. The following except one are viviparous animals A. pig B. cattle C. turkey D. goat
5. The hormone responsible for the contraction of the uterine wall during parturition is known as A. oxytocin B. progesterone C. luteinizing hormone, D.relaxin

THEORY

1. Draw and label the diagram of an egg.
2. List five reproductive hormones, site of secretion and their functions.