Learning Reproduction in Farm Animals

07-Oogenesis & Fertilization


Learning Objectives

Learning Objectives

Fate of follicles and oocytes.
Total # of follicles
At birth 100,000 
3 months  75,000
1½-3 year 21,000 
Aged cow  2,500
 
Follicles grow to tertiary characteristic and degenerate.

Maximum number of oocytes ovulated for a cow
17 cycles/year x 8 year = 136 oocytes ovulated/lifespan
 
 

Two types of ovulators:

  1. Induced - Rabbit, Cat and Camel

  2.  

     
     
     

    Intromission stimulates the surge of LH ovulation in rabbit is 10-13 hours after stimulation.
     
     

  3. Spontaneous - Farm animals and humans controlled by

  4.  events of estrus cycle and not affected by intromission.
     
     
Cystic Follicles - due to ovulation failure What Happens - hypothalamus pituitary and/or ovarian malfunction  Treatment of Repeat Breeders
 
 
 
 

Learning Objectives:

Prevention of Polyspermy and Polyploidy:

Coordination of events for fertilization to occur, i.e. Time of breeding relative to ovulation.

 
 
Ova

(hours)
Sperm

(hours)
Cattle 
20-24
30-48
Horse 
6-8
72-120
Sheep 
16-24
30-48
Swine 
8-10
24-72
 
 
Length of
Estrus
Timing of 
Ovulation 
Timing of
Insemination
Cattle
12-19 hours
10-11 hours (after
end of estrus)
7-18 hours (after 
onset of estrus)
Horse
2-11 days
1-2 days (before 
end of estrus)
2nd day of estrus
and every 2 days of 
rest of estrus.
Sheep 
24-36 hours 
24-36 hours (after 
onset of estrus)
12-18 hours (after 
onset of estrus)
Swine 
48-72 hours 
35-45 hours (after
onset of estrus)
16-24 hours (after onset of estrus)
2nd insemination 8-24 hours
after 1st insemination. 
 


Illustrated Notes

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