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 which influence growth, development and metabolic activities in farm animals. These include
| HORMONE | SEX | SITE OF SECRETION | FUNCTIONS |
| Testosterone/ Androgen | Male | Testes | It stimulates the development of secondary sexual characters in male. It stimulates sperm production through spermatogenesis. |
| Oestrogen | Female | Ovary | It stimulates the development of secondary sexual characteristics in female animals
It promotes the production of ova or eggs through oogenesis. It stimulates mammary gland development |
| Progesterone | Female | Corpus luteum | It ensures uterus development and implantation of the fertilized ovum.
It inhibits oestrus i. e. prevents ovulation. It stimulates the development of mammary gland It ensures the continuance of pregnancy. |
| Oxytocin | Female | Pituitary | It aids the contraction of the uterine wall during parturition.
It promotes milk let-down after parturition. It aids sperm transportation in the vagina. |
| Relaxin | Female | Pituitary | It aids relaxation of pelvic ligaments during parturition. |
| Follicle stimulating hormone (FSH) | Female | Pituitary | It stimulates the growth of ovarian follicle.
|
| Luteinizing hormone | Female | Pituitary | It stimulates the secretion of oestrogen and progesterone.
It causes the rupture of the follicle and the release of the ova from the follicle. |
GENERAL EVALUATION
- List five animal hormones and function.
- What are the functions of the following in the processes of egg formation in poultry?
- Ovary
- Oviduct
- Magnum
- uterus
WEEKEND ASSIGNMENT
- Which of these is not a part of the male reproductive system A. uterus masculinusB. oviduct C. testes D. vas deferens
- The following except one are female reproductive hormones A.oestrogenB. progesterone C. testosterone D. oxytocin
- Fertilization in poultry birds takes place in the A. infundibulum B. isthmus C.magnumD. uterus
- The following except one are viviparous animals A. pig B. cattle C. turkey D. goat
- 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
- Draw and label the diagram of an egg.
- List five reproductive hormones, site of secretion and their functions.
See also
REPRODUCTION IN FARM ANIMALS
RESPIRATORY SYSTEM
ANATOMY AND PHYSIOLOGY OF FARM ANIMALS
FARM MECHANIZATION
FARM POWER