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The Maritime Bull Gazette
Bull Repro-Assessment
April 4th, 2015
Issue 1
Factsheet 2
Breeding Soundness Evaluation
The breeding soundness evaluation is used to evaluate the potential fertility of a bull
and is based on an examination that includes physical examination, scrotal
circumference and semen quality. The goal is to identify the bull’s breeding capacity in
an objective manner.
Physical Soundness: is important to ensure
breeding ability (mobility and mounting).
Physical Examination
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●
●
Body weight and body condition score (B);
Conformation and fitness of feet and legs (B);
Eyes (A) and general health.
B
A
Reproductive System: is important to understand the reasons of poor semen quality
● The scrotum, testes and epididymis are palpated and ultrasound scanned (D);
● The internal organs (i.e. seminal vesicles) are palpated and ultrasounded (E). Scrotal
Circumference: is positively associated with sperm count and semen quality
● Testes are held at the base of the scrotum and the larger diameter is measured (F).
C
D
E
F
Semen Evaluation
Sperm Motility: is an important indicator of the sperm capacity of reaching the egg.
●
●
Semen is examined under the microscope for assessment of motility patterns;
The percentage of immotile and motile sperms are assessed.
Semen Evaluation
Normal Sperm Morphology: is associated with maturity and improved fertility
● Dead sperm take up the stain and appear pink while live sperms stay white;
● Sperm morphology is classified as normal or abnormal which include: head defect,
midpiece defect, tail defect, loose head and proximal droplets, as illustrated below.
Normal
Head Defect
Mid-Piece
Defect
Tail
Defect
Loose
Head
Proximal
Droplet
Reproductive Classification and Interpretation
Table 1: Minimum Requirements for Classification as
a Satisfactory Potential Breeder and Examples
Decision
Scrotal
Circumference
Sperm
Motility
Normal
Sperm
Satisfactory
≥ 30 cm
≥ 30%
≥ 70%
Bull A
36.7 cm
90%
92%
Deferred
Signs of sexual immaturity or recoverable
injuries
Bull B
32.4 cm
70%
42%
Unsatisfactory
< 30 cm
< 30%
< 70%
Bull C
33.5 cm
10%
7%
Stéphanie Bourgon, Jasper Munro, Ellen Crane,
Yuri Montanholi - Dalhousie University (e-mail:
[email protected])
Bull A:
Met all minimum requirements
Bull B:
<70% normal sperm, most
abnormalities were proximal
droplets (sign of immaturity)
Bull C:
<30% motility and <70%
normal sperms with no sign of
immaturity