STUDY ON GROSS TESTICULAR DISORDERS OF BULLS SLAUGHTERED AT ADDIS ABABA

ABATTOIRS ENTERPRISE

1Migbaru K., 2Sisay. G. and 3Kasa T.1, 2College of veterinary medicine, Haramaya University, Dire Dawa,

Ethiopia.3Aklilu Lema institute of Pathobiology, Faculty of veterinary medicine,

Addis Ababa university, Debire Zeit, Ethiopia.

ABSTRACT

A cross-sectional study using systematic random sampling was conducted

on antemortem and postmortem examination of 384 intact bulls slaughtered

at Addis Ababa Abattoirs Enterprise (AAAE) from November, 2009 up to

April, 2010 to identify different types of testicular disorders of the

bull presented to the abattoir and to determine the rate of occurrence

of each disorder and also to assess the associated risk factors. Out of

384 intact bulls examined 337 were local, 29 cross and 18 exotic breeds

brought from different market areas in the country, of which 117 (30.4%)

have scrotal and testicular disorders. During study time various

testisticular defects such as scrotal torsion, scrotal wound, orchitis,

epididymitis, testicular hematoma, testicular degeneration, testicular

hypoplasia and cryptorchidism with the prevalence of 1%, 4.7%, 4.4%,

3.4%, 2.1%, 8.1%, 3.6% and 2.6% respectively were identified. Only

testicular degeneration has significant association with age (χ2 = 8.9,

P < 0.05).

Key words: Addis Ababa Abattoirs Enterprise, Intact bull, Infertility, Testicular disorder.

INTRODUCTION

Agriculture (mainly crop and livestock production) is the mainstay of

the sub-Saharan countries and for 85% of Ethiopian population. Livestock

production accounts for approximately 30%of the total agricultural gross

domestic production and 16% of national foreign currency earnings

(Lobago, 2007). The population of cattle in the country is estimated at

41.5 million comprising 99.4% indigenous (zebu), 0.5% cross and 0.1%

exotic breeds which are mainly kept under smallholder subsistence

farming (EASE, 2003), from this 43.12 million cattle population are for

the rural sedentary areas of, of which 55.41% are females and 44.59 are

males (CSA, 2006).

In Ethiopia the productivity like meat, milk, cheese, butter, export

commodities (live animals, hide, skin) and draught power (EASE, 2003) of

livestock does not commensurate with the large size due to various

reasons such as occurrence of diseases, poor management systems,

inadequate nutrition and animal health services, selection and

improvement for productivity (Lobago, 2007).

Reproductive performance is one of the major determinants of cattle

productivity in any production systems. The contribution of the bull

either through the natural mating or artefitial insemination (AI) is the

determinant factor, because each bull represents half of the genetic

composition of its progeny and many cows can be inseminated with the

semen of a single bull (Faulkner and Pineda, 1980).

Failure of many bulls to breed consistently and efficiently has been

reported to be associated with the production of poor quality semen due

to the pathology of testes and accessory glands. Gross testicular

pathology is classified as congenital causes like hypoplasia and

criptorchidism and acquired causes like testicular degeneration,

orchitis, calcification, testicular hematoma and epididymis. All of the

abnormalities have a negative effect on productivity and fertility of

the bull (Hafez, 1993).

Pathologic condition of testes, epididymis, and seminal vesicle have

been recognized to interfere with fertility by disturbing

spermatogenesis or sperm maturation, leading to abnormal semen

characteristics or preventing the passage of spermatozoa from testes to

urethra (Van Camp, 1997). Some of such disease conditions include:

testicular degeneration, orchitis, hematoma and epididymitis (Hafez,

1993). The possible causes of these acquired testicular abnormalities

are infectious agents, nutrition, managemental factors, thermal

influence, and age (Rao and Bane, 1985).

Infertility is a global problem, but the highest prevalence is within

low resource countries, particularly in sub-Saharan Africa where

infection related tubal damage is the commonest case. Acute or chronic,

localized or systemic infectious diseases are common causes of bull

infertility and testicular degeneration in Ethiopia due to wide spread

presence (Mamo, 1988).

Bulls which are older than seven years have 0.3 to 0.5% reductions in

fertility due to lower sperm production owing to higher incidence of

lesions such as testicular fibrosis and tubular calcification that

develops testicular degeneration (Sullivan, 1978).

Testicular disorders of bull has a great economic effect due to

reduction in fertility rate of cows in Ethiopia because most of the

people are dependent on pastoral and agro pastoral practices and this

practice is mostly extensive farming system (CSA, 2006). The farmers

didn’t use artificial insemination rather they use their bulls for

natural mating without selecting healthy, good sexual desire or good

fertilization capacity bulls (Coulter and Foote, 1979). The objectives

of this study were: (1) to identify the different types of gross

testicular disorders of the bull presented to AAAE, (2) to determine the

rate of occurrence of the observed disorders and (3) to examine the

associated risk factors.

MATERIALS AND METHODS

Study Area

The study was conducted in Addis Ababa, the capital city of Federal

Republic of Ethiopia, at Addis Ababa Abattoirs Enterprise. Addis

Ababa is located at an elevation of 2020-2500 meters above sea

level.

Study animals and sampling strategy

A cross-sectional study design was employed to identify major

testisticular disorders and possible risk factors on intact bulls.

The study was conducted on intact bulls slaughtered at Addis Ababa

Abattoirs Enterprise from November, 2009 to April, 2010. The study

animals comprise of male indigenous, exotic and cross breeds of

cattle which brought from different areas of the country like

Harare, Jima, Nazreth, Wolayta and others. Age of the animal was

estimated by dentition (de-lahunta and Habel, 1986).

To determine gross testicular disorders of bulls, antemortem and

postmortem examination were employed. During examination attention

was given to the scrotum and testes of intact bulls to identify

scrotal defects and gross testicular disorders by careful

visualization and palpation followed by postmortem examination by

making lateral dissection to visualize the cut surface whether it

bulges out or not according to Hafez (1993). Accordingly; 384 intact

bulls were selected and examined using systematic random sampling

technique according to Thrusfield (2005) with 95% confidence

interval; at 5% desired absolute precision and 50% expected

prevalence to give maximum sample size.

Data Management and Analysis

Data generated from antemortem and postmortem inspection was

recorded in the Microsoft excel 2007 program. The data was analyzed

by using SPSS version 17. Point prevalence of defects was calculated

as percentage by dividing the frequency of each defect to the total

number of bulls examined in the abattoir and the proportion of each

disorder was calculated by dividing the frequency of each case to

the total number of cases. The significance of association among the

risk factors and the case was determined by Chi-square test at p ≤

0.05.

RESULTS

Prevalence and proportion of Antemortem and Postmortem Examination

Disorders

The possible defects of the scrotum on antemortem examination were

scrotal torsion and scrotal wound with the prevalence of 1% and 4.7%;

and 3.4% and 15.4 % case proportion respectively. Among the lesions on

postmortem examination testicular degeneration, orchitis, testicular

hypoplasia, epididymitis, cryptorchidism and testicular hematoma were

identified with 8.1%, 4.4%, 3.6%, 3.4%, 2.6% and 2.1% prevalence and

26.5%, 14.4%, 12%, 11%, 10.3% and 6.8% case proportion respectively

(Table.1).

Table 1: prevalence and case proportion of

antemortem and postmortem examination

disorders.Antemortem Post mortem

ST SW Tot Orc Ep TH THyp TD Cryp tota

lFrequency 4 18 22 17 13 8 14 31 12 95

Prevalence 1 4.7 5.7 4.4 3.4 2.

1

3.6 8.1 3.1 24.7

Case

proportion

3.

4

15.4 18.

8

14.4 11 6.

8

12 26.5 10.3 81.2

SW= Scrotal Wound, ST= Scrotal Torsion, TH= Testicular Hematoma, TD=

Testicular Degeneration, Orc= Orchitis, THyp= Testicular Hypoplasia,

Cryp= Cryptorchidism Ep= Epididimitis Tot=total

Antemortem Examination Disorders

During antemortem examination, 5.5 % of examined bulls have scrotal

defects like 1 % scrotal torsion and 4.7 % scrotal wound. These defects

were observed 6.2 % on local, 3.4 % on cross and no observed defects on

exotic breeds. Based on age 3.7 %, 5.8 % and 6.1 % were observed on

below four years, between four and six and above six years age

respectively. Origin wise 2 %, 6.6%, 6.1% and 4.3 % were from Harar,

Jimma, Nazreth and wolayta respectively but the remaining 8.4% were from

unknowen sources (Table 2).

Table 2: Summary of antemortem examination defects based on breed, age

and origin of bulls slaughtered in AAAE.

variables Total

examined

Scrotal Torsion

(%)

Scrotal Wound (%) Total (%)

Breed

Local 337 4 (1.1) 17 (5) 21 (6.2)Cross 29 0 (0) 1 (3.4) 1 (3.40Exotic 18 0 (0) 0 (0) 0 (0)Total 384 4 (1) 18 (4.7) 22 (5.7)

χ2 = 0.56, P =

0.75

χ2 = 1.09, P =

0.582

Age<4 54 (14.1) 1 (1.9) 1 (1.9) 2 (3.7)4-6 104

(27.1)

1 (0.96) 5 (4.8) 6 (5.8)

>6 226

(58.9)

2 (0.88) 12 (5.3) 14 (6.1)

Total 384 (100) 4 (1) 18 (4.7) 22 (5.7)χ2 = 0.4, P =

0.82

χ2 = 1.2, P = 0.56

OriginHarar 97 (25.3) 0 (0) 2 (2) 2 (2)Jima 76 (19.8) 0 (0) 5 (6.6) 5 (6.6)Nazreth 33 (8.6) 1 (3) 1 (3) 2 (6.1)Unknown 131

(34.1)

2 (1.5) 9 (6.8) 11 (8.4)

Wolayta 47 (12.2) 1 (2.1) 1 (2.1) 2 (4.3)Total 384 (100) 4 (1)

χ2 = 3.94, P =

0.42

18 (4.7)

χ2 =4.39, P = 0.355

22 (5.7)

Post Mortem Examination Disorders

Among the postmortem examination disorders, age has significant

association with testicular degeneration (χ2 = 8.9 and P = 0.012) (Table

3).

Table 3: Summary of postmortem examination gross testicular disorders

based on breed, age and origin of bulls slaughtered in AAAE.

variabl

es

Total No (%) Hypoplas

ia (%)

Cryptorchi

dism (%)

Orchitis

(%)

Epididymit

is (%)

Hemato

ma (%)

Degenera

tion (%)Breed

Local 337(87.8) 13

(3.8)

11 (3.3) 16

(4.75)

12

(3.6)

7 (2) 28 (8.3)

Cross 29 (7.6) 1 (3.4) 1 (3.4) 0 (0) 1 (3.4) 1

(3.4)

2 (6.8)

Exotic 18 (4.7) 0 (0) 0 (0) 1 (5.6) 0 (0) 0 (0) 1 (5.5)Total 384 (100) 14

(3.6)

12 (3.1) 17

(4.4)

13

(3.4)

8

(2.1)

31 (8.1)

χ2

p-

value

0.73

0.69

1.87

0.76

1.47

0.477

0.663

0.718

0.648

0.723

1.12

0.57

Age<4 54 (14.1) 2 (3.7) 2 (3.7) 1 (1.9) 1 (1.9) 0 (0) 1 (1.9)4-6 104 (27.1) 4 (4) 3 (2.9) 5 (4.8) 4 (3.8) 3

(2.9)

4 (3.4)

>6 226 (58.9) 8 (3.5) 7 (3.1) 11

(4.9)

8 (3.5) 5

(2.2)

26

(11.5)Total 384 (100) 14

(3.6)

12 (3.1) 17

(4.4)

13

(3.4)

8

(2.1)

31 (8.1)

χ2

p-

value

0.02

0.99

7.4

0.115

0.99

0.61

0.47

0.79

1.5

0.47

8.9

0.012

Origin Harar 97 (25.3) 3 (3) 3 (3) 3 (3) 2 (2) 1 (1) 3 (3)Jima 76 (19.8) 2 (2.6) 2 (2.6) 3 (3.9) 3 (3.9) 1

(1.3)

6 (4.9)

Nazreth 33 (8.6) 2 (6) 1 (3) 2 (6) 1 (3) 1 (3) 3 (9)Unknown 131 (34.1) 6 (4.5) 4 (3) 8 (6.1) 6 (4.6) 4 (3) 16

(12.2)Wolayta 47 (12.2) 1 (3) 2 (4.2) 1 (2.1) 1 (2.1) 1

(2.1)

3 (6.4)

Total 384 (100) 14

(3.6)

12 (3.1) 17

(4.4)

13

(3.4)

8

(2.1)

31 (8.1)

χ2

p-

value

1.49

0.83

2.2

0.97

2.1

0.71

1.4

0.82

1.5

0.88

6.5

0.17

Figure 1: Testicular calcification Figure 2:

Scrotal torsion

Figure 3: Testicular hematoma figure 4: Unilateral

testicular degeneration

Figure 5: Testicular abscess Figure 6: unilateral

hypoplasia of testes

DISCUSION

The prevalence of gross testicular disorders from antemortem and

postmortem examination during the study period was 30.4% (117 cases from

384 intact bulls examined). This result is not far below with the report

of 41% by Joe et al., (2001) in UK. Out of this 18.8% (22 out of 117 cases)

were scrotal defects found during antemortem examination which is not

far below from 28%, the report of Jubb and Kennedy, (1970) in Israel.

This variation might be due to the exclusion of penile disorders in this

study. These scrotal defects were scrotal torsion (1%) and scrotal

wounds (4.7%) are similar with 1.03% and 4.3% respectively (Kastelic et

al., 2001) in Canada. None of the scrotal defects have significant

association (p > 0.05) with the risk factors.

The presences of these scrotal defects have a negative effect on

fertilization capacity of breeding bulls. For instance scrotal torsion

or wound results circulatory interference and infarction of the testes

which can be produced by manually or naturally occurring scrotal

torsions or contusions mostly in animals with vigorous exercise and the

testes would be swollen, congested and leads to degeneration and also

interferes free movement of the scrotum up and down, that prevents

counter current mechanism of thermoregulation (Hafez, 1993).

During postmortem examination of 384 intact bulls 95 bulls have gross

testicular disorders that are 24.7% from the total (384) and 81.2% of

the total cases (117) of both antemortem and postmortem defects. This

result was not far above that of 72% reported by Jubb and Kennedy,

(1970) in Israel. In this study testicular degeneration was the most

frequently encountered (8.1%) among the gross testicular disorders which

are comparable with the report of 7.6 ± 1.9% in Belgian Blue bulls and

10 ± 4% in Holstein Frisian bulls in Belgium by Hofka et al., (2009).

Testicular degeneration is the leading because most adverse conditions

like high ambient temperature or pyrexia from disease stress due to

excessive physical work and also produced by other gross lesions like

orchitis, epididymitis. Orchitis and epididymitis were the second and

third prevalent defects with 4.4% and 3.4% prevalence respectively

(Trojian et al., 2009). The rest were testicular hypoplasia 3.6% which has

a negative effect on semen quality and volume (Barth and Oko, 1989) and

Cryptorchidism with the frequency of 3.1% which affects spermatogenesis

by inhibiting testicular thermoregulation (Marcus et al., 1997) and also

testicular hematoma with 2.1% prevalence. Testicular degeneration and

testicular hypoplasia are difficult to differentiate during antemortem

examination but during postmortem examination testicular degeneration is

firm on palpation and does not budged out while dissection (figure 4)

but testicular hypoplasia has flaccid consistency and bulged out while

dissection (figure 6) (Van Camp, 1997).

In this study only testicular degeneration had significant association

(χ2 = 8.9, p < 0.05) with the age but not to the other risk factors. The

absence of significant association between the antemortem and postmortem

examination defects with the risk factors except testicular degeneration

might be due to different possible reasons, considered as limitations of

this study. Depending on age that might be due to low number of young

bulls came to the abattoir that makes the data sensitive with the

presence of very small number of cases. On species wise even if exotics

and cross breeds were managed with intensive and semi intensive farming

system they have low resistance to the adverse environmental conditions

than local zebus (MOA, 1996). Also some intensive farm owners might cull

bulls with reproductive disorders that increase the occurrence in the

abattoir. On the other hand extensive farm owners might use the bulls

for natural mating with the problem that reduces the case during the

study. In case of origin there was no great variation of the occurrence

that might be due to most of the bulls have collected in different

environmental conditions even if they recorded as the same origin.

Therefore, to know the effect of these risk factors on reproductive

organ disorders of intact bulls needs farther research by taking

proportional samples from each type of management system, age group,

breed and also environmental conditions (Leke et al., 1993).

CONCLUSION AND RECOMMENDATIONS

The result of this study indicates that high number of intact bulls have

gross testicular disorders which can affect the fertilization capability

of breeding bulls. From this study antemortem disorders are due to poor

management like scrotal trauma by noxious agents and kick wounds and

also ectoparasite infestation around the scrotum that causes scrotal

dysfunction. Postmortem disorders may be due to localized/ systemic

diseases and congenital defects like cryptorchidism and testicular

hypoplasia. Also the study indicates that high rate of gross testicular

disorders were on aged intact bulls (≥6 years). Even if there are many

reproductive organ disorders that have impact on the reproductive

performance of bulls and cows researchers have given attention only for

cows.

Based on the above conclusion the following recommendations are

forwarded:

Bull selected for breeding should be free from gross testicular

lesions, small or unequal sized and incomplete descended testes

and scrotal problems.

Selected breeding bulls must be kept in good management system and

should not be aged.

Research must be done routinely on the problem regard to the

reproductive performance of bulls.

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