PROCESSES OF EGG FORMATION IN POULTRY
The egg in poultry is partly formed in the ovary and the oviduct. At ovulation, the ovum carrying the yolk is released by the ovary into the oviduct through the funnel called the infundibulum.
Fertilisation 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 around 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 and 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
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.OestrogenFemaleOvaryIt stimulates the development of secondary sexual characteristics in female animals
- It promotes the production of ova or eggs through oogenesis.
- It stimulates mammary gland developmentProgesteroneFemaleCorpus luteumIt ensures uterus development and implantation of the fertilised ovum.
- It inhibits oestrus, i.e. prevents ovulation.
- It stimulates the development of the mammary gland
- It ensures the continuance of pregnancy.OxytocinFemalePituitaryIt aids the contraction of the uterine wall during parturition.
- It promotes milk let-down after parturition.
- It aids sperm transportation in the vagina.RelaxinFemalePituitaryIt aids relaxation of pelvic ligaments during parturition. Follicle-stimulating hormone (FSH)FemalePituitaryIt stimulates the growth of ovarian follicles.
- Luteinizing hormoneFemalePituitaryIt 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 their functions.
- 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 masculinus B. oviduct C. testes D. vas deferens
- The following except one is are female reproductive hormone, oestrogen. progesterone C. testosterone D. oxytocin
- Fertilisation in poultry birds takes place in the A. infundibulum, B. isthmus, C. magnum, D. uterus
- The following except one are viviparous animals: A. pi,g B. cattl,e C. turke,y 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, the site of secretion and their functions.
See also
Definition and Objectives of Export Promotion in Agriculture
Agricultural Insurance | Meaning, Importance, Types, Risks, Problems & Terminologies
Agricultural Marketing | Co-operative Societies, Producers, Middlemen, Wholesalers,