Learning Reproduction in Farm Animals

13-Male Reproductive Capacity


Learning Objectives

 

Factors affecting physical ability to mate:

  1. Back and leg problems

  2.  
  3. Poor senses - vision, odor, etc.

  4.  
Total available sperm production: Quality of sperm produced:
 
Sperm viability i.e. % of sperm in ejaculate that are alive
  1. Sperm abnormalities
    1. Causes:
        Genetic
         
         Stress - Temperature, phychological
         
         
         
         
         
         
         
         
         
  2. Testis tone indicates sperm quality

  3.  
Breeding management of the male
       
      1. Factors affecting

      2.  
        • Age of male

        •  
        • Physical size

        •  
        • Size and pasture conditions

        •  
        • Male to female ratios

        •  
        • Nutrition

        •  
      3. Recommendations for breeding activities of male

      4.  
           
          ARTIFICIAL INSEMINATION 
          (Steady sperm production)
          Ejaculations/week 
          Pasture
          Stallion
          3-5
          Bull
          4-6 
          1/30-1/45
          Boar 
          2-3 
          ~ 1/10
          Ram 
          6-20's 
                     1/40-1/80
           
      5. Acquired fertility problems

      6.  
        • Testicular degeneration

        •  
            Aging, infection, nutrition (Vit. A)
             

            Thermal stress
             

        • Diseases

        •  
            Orchitis - Brucellosis, tuberculosis
             

            Epididymitis - Brucellosis, viral infection
             

            Seminal vesiculitis - Brucellosis
             

        • Formation of antibodies against sperm

        •  
           
           

Testing Bull Fertility


Serving capacity of bull is defined as:

 
 
 
 
 
 
 
 
 

Serving Capacity Test:
 

  1. Non-estrous heifers or cows are restrained in service crates in large yard. If 8 bulls used, 10 females would be restrained.

  2.  
  3. Bulls are sexually stimulated by allowing them to watch other bulls mounting females.

  4.  
  5. Bulls are then allowed with females for 40 minutes and number of services (not mounts) are counted.

  6.  

     
     
     

 
Serving Capacity of Bull  Conception Rate  Pregnancy Rate
0 - 2  21%  30%
3 - 6  60%  92%
7 - 11  73%  97%
 
Serving Capacity in 40 minutes  Mating potential
(Cows in 3 weeks)
3
40
4 - 5 
45
50 
8 
55 
60 
10 
65 
11 
70 
12 
75
 
Testicle size and mating load
To be successfully mated 
to X females 
A bull must have a minimum 
scrotal circumference of Y
 40        30 cm 
60 32
80 34
Blockey M.A. 1981 Applied Anim. Ethology 7:307

Illustrated Notes

Copyright © 2006. All rights reserved.