ANS 431: Poultry Reproduction

Female--Heterogametic Sex

I.	The Egg

	1.	Components
		A.	Ovum (Yolk)
		B.	Albumen (White)
		C.	Shell

	2.	Ovum (Yolk)
		A.	Vitelline membrane
		B.	Germinal Disc
			a.	Blastodisc (infertile)
			b.	Blastoderm (fertile)
		C.	White Yolk
		D.	Yellow Yolk		
			a.	Provides "building blocks" for embryogenesis
 	3.	Albumen (White)
		A.	7 layers
			a.	Formed by rotation of egg in oviduct
		B.	Prevents Desiccation
		C.	Contributes material to late embryo
		D.	Bactericidal

	4.	Shell
		A.	Membranes
			a.	Inner
			b.	Outer
			c.	Provide surface for mineralization
		B.	Mineralized Part
			a.	Calcium Carbonate
		C.	Cuticle
			a.	Reduces Water Loss
			b.	Reduce Bacterial Contamination

II.	Female Anatomy/Egg Formation

	1.	Ovary
		A.	Only left ovary and ductal system develop past 
			embryogenesis
			a.	MIF inhibits right side only
		B.	Follicle destined to ovulate forms every 25-27 hours
		C.	Ovulates 5-7 days later
		D.	Yolk is made
			a.	Proteins comes from liver
			b.	FSH control

	2.	Oviduct
		A.	Infundibulum
			a.	Site of fertilization
		B.	Magnum
			a.	Albumen secreting
			b.	Progesterone control
		C.	Isthmus
			a.	Forms Shell Membrane
	3.	Shell Gland (Uterus)
		A.	Plumping
			a.	Water added to white
		B.	Calcification
			a.	Estrogen Control
		C.	20 hours

	4.	Uterovaginal junction
		A.	Sperm Storage Tubules
		B.	Sperm Life
			a.	Chicken--32 days
			b.	Turkey--70 days

	5.	Vagina

	6.	Cloaca

III.	Male Anatomy	

	1.	Testis
		A.	Internal
			a.	Lies between Lung and Kidney

	2.	Ducts
		A.	Epididymal region
		B.	Vas Deferens

	3.	Phallus
		A.	Wart-like structure at cloaca

IV.	Egg Production

	1.	Sexual Maturity
		A.	Chickens--5-6 months
		B.	Turkeys--7-8 months

	2.	Oviposition--Laying
		A.	Shell gland contracts
		B.	Hormonal (and Neuronal) Control
			a.	Vasotocin
			b.	Prostaglandins
		C.	Occurs every 25-27 hours
		D.	Clutch
			a.	An egg a day before a skipped day
			b.	Decreases with age: 10-20 to 4-5 day
			c.	Directly related to time to ovulation
	3.	Ovulation
		A.	Caused by two LH peaks
			a.	Dusk
			b.	Preovulatory (early morning)
				--4-6 hours before ovulation

	4.	Molting
		A.	Loss of feathers and cessation of laying
		B.	Gradual insensitivity of hypothalamus 
			to positive feedback of Progesterone
		C.	Last 4-6 weeks--Once a year				


V.  Mating & Fertilization.		

	1.	No intromission

	2.	Erected Phalus makes contact with inverted vagina

	3.	Long sperm life in female tract (1 or 2 months)

	4.	Released Episodic

	5.	Polyspermy occurs but only one male pronucleus fuses
	6.	A.I.

		A.	Becoming very common in commercial operations
			a.	Nearly 100% of Turkeys
		B.	Semen Collection
			a.	Abdominal massage
			b.	"Milk" cloaca after erection
			c.	Ejaculate:  0.25 ml
					Chicken--5 billion sperm/ml
					Turkey--9 billion sperm/ml
		C.	Insemination
			a.	Breaking or venting
				--exteriorization of vaginal orfice
			b.	Straw insemination
				--Dosing gun

VI.	Fertility & Hatching

	1.	Incubation period
		A.	Chicken--21 days
		B.	Turkey--28 days
		C.	Duck--28 days
		D.	Goose--30-33 days

	2.	Candling
		A.	Intense light transmitted through egg
		B.	Look for vascularization of embryo
			--day 5-10
		C.	Determines Fertility

	3.	Mortality
		A.	1st 5 days
		B.	Last 3 days

	4.	Hatchability
		A.	Offspring hatched/fertile candled eggs




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~~~~~Revised 12/28/96~~~~~ TAW