SUBJECT: AGRICULTURAL SCIENCE
CLASS: SS1
DATE:
TERM: 3RD TERM
REFERENCES
WEEK SEVEN
REPRODUCTION IN FARM ANIMALS II
CONTENT
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.
EVALUATION
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
READING ASSIGNMENT
WEEKEND ASSIGNMENT
THEORY
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