






























 
*Corresponding author: 
  Email: berhanumm2002@gmail.com, Phone  +251- 91 024 8878  
 
 

 

 

Study on clinically manifested reproductive health problems of dairy cows managed 
under intensive and semi-intensive production systems in Wondo Genet district, 

Southern Ethiopia 
Amene Fekadu1, Yifat Denbarga1,Tesfaye Belay2, Desie Sheferaw1, Fufa Abunna3, Kebede Amenu3, 

Rahmeto Abebe1, Mesele Abera1, Berhanu Mekibib1* 

1Hawassa University, Faculty of Veterinary Medicine, P.O.Box 05, Hawassa, Ethiopia 
2Hawassa University, College Forestry and Natural Resources, Wondo Genet, Ethiopia 
3Addis Ababa University, College of Veterinary Medicine, P.O.Box 34, Bishoftu, Ethiopia 

 
 

KEYWORDS:  

Dairy cows;  

Production constraint;  

Bovine brucellosis;  

Wondo Genet 
 

 

 

 

 

 

 

 

 

 

ABSTRACT 
Reproductive disorders in cows are crucial as reproduction and fertility are the two key 
pillars of dairy production profitability. The study was conducted to identify and estimate 
the prevalence of clinically manifested postpartum reproductive disorders, to identify the 
associated risk factors and to estimate the sero-prevalence of brucellosis in dairy cows 
kept under intensive and semi-intensive dairy farms in Wondo Genet district from 
November 2019 to September 2020. Out of the total 205 cows examined, 90 cows 
(43.90%) had at least one of the reproductive problems identified by either questionnaire 
interview or regular follow up of individual cows. Out of 146 cows retrospectively and 59 
cows prospectively assessed for the presence of any reproductive disorder, 62 (42.47%) 
and 28 (47.46%) cows had at least one reproductive disorders, respectively. Retained fetal 
membrane, abortion, uterine infections, anestrous and repeat breeding are the major 
reproductive disorders encountered followed by dystocia, milk fever and prolapses of the 
vagina and/or uterus. Among the considered host and management related risk factors, 
only presence of previous reproductive disorder had statistically significant association 
with the occurrence of reproductive disorder (p<0.05). This study also demonstrated that 
none of the serum samples collected from Wondo Genet and other towns (namely 
Hawassa, Wolaita Sodo and Arsi Negelle) and tested using Indirect Multi-species ELISA 
was positive for bovine brucellosis. Further studies, preferably laboratory based, should be 
conducted to identify the underlined causes of these problems in different parts of the 
country. Meanwhile, awareness should be created to farm owners/attendants to improve 
their farm management system. 

 

INTRODUCTION 

Dairying is one of the livestock productions 
practiced almost all over Ethiopia, involving a 
vast number of small, medium, or large-sized, 
subsistence or market-oriented farms (Abera, 

2016). The dairy sector is dominated by 
traditional smallholder farmers who account for 
about 85% of the population and are responsible 
for 98% of the milk production (MoARD, 
2007). Unfortunately, nearly 90% of the milk 
produced by the rural household is consumed 

Journal homepage : https://journals.hu.edu.et/hu-journals/index.php/eajbcs 
  Hawassa University

College of Natural & Computational Sciences

Year 2021

Volume xx No xx

14

East African Journal of Biophysical and Computational Sciences 

East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1, 14-26
  

Research article

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East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1 
 

 

within the producer households with the 
proportion marketed being not more than 10% 
(CSA, 2020)  

Owing to the rapidly increasing population size, 
low productivity of the local breeds (1.32 
liter/cow per day), a growing urbanization and 
the concomitant growing demand for dairy 
products, the country is already in a very high 
demand-supply variance (Seifu and Doluschitz, 
2014). To partly fill this gap, the country 
expends over 10 million USD annually for the 
import of dairy products from different 
countries (Tegegne et al., 2016). For a 
sustainable economic growth, however, both the 
public and private sectors are engaging in urban 
and peri-urban dairy development (Seifu and 
Doluschitz, 2014; Edao et al., 2018).  

Despite the progressive growth in the 
commercial (market oriented) dairy farming in 
urban and peri-urban settings, the dairy industry 
is still underutilized and challenged by several 
factors. In general the development of the dairy 
sector is hindered by poor management system, 
shortage of proper nutrition, absence of well-
developed market infrastructures and 
widespread infectious and parasitic diseases 
(MOA, 1998). Among health related issues, 
reproductive disorders in cows are crucial as 
reproduction and fertility are the two key pillars 
of dairy production profitability (LeBlanc, 
2008). These problems, caused by infectious 
and non-infectious causes, are responsible to 
reduce milk yield and subsequent reproductive 
performance of dairy cows (Rajala and Gröhn, 
1998; LeBlanc et al., 2002; LeBlanc, 2008) and 
ultimately cause premature and forced culling of 
high producing dairy cows (Esslemont and 
Peeler, 1993).  

Bovine brucellosis, a bacterial zoonotic disease, 
is one of the infectious diseases assumed to 
hamper productivity of cattle in the country 
(Ibrahim et al., 2010; Edao et al., 2018). The 
disease in cattle is characterized clinically by 
abortion at third trimester of first gestation, 
retained fetal membrane (RFM), metritis, 
orchitis and epididymitis (Radostits et al., 
2006). Bovine brucellosis has been reported 
from several parts of the country, particularly in 
cows kept in intensive and extensive 
management systems. However, recent reports 
particularly from central and southern Ethiopia 
are revealing a very low to zero prevalence 
(Alem and Solomon, 2002; Belihu, 2002; 
Asmare et al., 2013; Bashitu et al,.2015, Edao et 
al., 2018). 

Although several studies have been conducted 
on the prevalence of bovine brucellosis (Asmare 
et al., 2013; Edao et al., 2018; Ataro e al., 2019; 
Dinknesh et al., 2019) and/or on the major 
reproductive disorders (Lobago et al., 2006; 
Hunduma, 2013; Wujira and Nibret, 2016; 
Yohannes and Alemu, 2019), majority are 
limited in the central highland, dairy farms of 
research centres and major towns/cities of the 
country. However, there is still paucity of 
information in some parts of the country 
including Wondo Genet district. Moreover, the 
scope of reproductive health in the dairy 
industry still demands more intensive 
investigation for better formulation of 
prevention strategies. Therefore, the present 
study is intended to identify and estimate the 
prevalence of the major clinically manifested 
postpartum reproductive disorders, to identify 
the associated risk factors and to estimate the 
sero-prevalence of brucellosis in dairy cows 
kept under intensive and semi-intensive dairy 
farms in Wondo Genet district. 

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East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1 
 

 

MATERIALS AND METHODS 

Study area 

Study design 

Study design and sample size 

Both retrospective (questionnaire based) and 
prospective (follow-up and serological) studies 
were undertaken from November 2019 to 
September 2020 to estimate the prevalence of 
major reproductive problems in dairy cows. All 
female cattle with at least one calving history 
were purposively selected for the retrospective 
survey. For the prospective follow-up study, 
however, all pregnant cows and heifers (in their 
first pregnancy) which were at 4th or more 
months of gestation were selected and registered 
according to their ear tag numbers /given name 
for follow-up.  

Study population and Study animals 

16

The  study  was  conducted  in  Wondo  Genet 
district,  which  is  located  24km  North  East  of 
Hawassa, the capital city of Sidama Regional 
state and 265.km to South of Addis Ababa, the 
capital of the country, Ethiopia. The district 
is classified administratively into 13 rural and 2
 urban  villages.  It  has  temperature  and  altitude 
ranging  from  7  to  26 °C  and  1761  to  2695 m 
above  sea  level,  respectively.  The  average 
rainfall  is  1120 mm per annum and the main 
rainy  season  in  the  area  is  between  July  and 
early October (Bolka and Gebremedhin, 2019).
 In  the  area,  animal  husbandry  is  the  main 
subsistent  farming  where  cattle,  sheep,  goats 
and equines are the species of animals found 
(Jones  et  al.,  2011).  The town is  known for its 
high potential in dairy production in Southern 
Ethiopia  and  major  source  of  milk  and  other 
dairy products. 

The number of cattle required for serological 
survey was calculated based on the formula 
described by Thrusfield and Brown (2018), with 
5% absolute precision with 95% confidence 
level. Moreover, a prevalence (2.7%) 
reported by Ataro et al. (2019) from Hawassa 
was used as expected prevalence as there is no 
previous report from Wondo Genet and its 
surroundings. As a result, the sample size 
computed was 40 for the study area. However, 
the sample size was increased by 5 fold and 
hence a total of 200 cows were randomly 
selected and examined. Moreover, equal 
numbers of animals were also sampled from the 
different farms found in Hawassa, Arsi Negelle 
and Wolaita Sodo for serological survey. 

The study population constituted all the dairy 
cows found in Wondo Genet district. The 
majority of dairy producers included in this 
study  were  market  oriented  small  holder 
dairy farmers  with  average  herd  size  of  10 
cows.  Although majority of the farms are small 
scale,  there  are  also  few  governmental  and 
private owned  large  (commercial)  scale  dairy
 farms  with  heard  size  of  over  50.  Most  of 
these  farms rear  crossbred  dairy  cattle  under  
semi-intensive management  system. Hay and
concentrate (wheat  bran,  molasses  and  oil  
and  brewery  by- products)  were  the  common 
types of feed used in  almost all farms. Majority
 of  the  management  activities  including  heat  
detection  (detection  for the  major  oestrus  sign 
of  the  cows)  were  done by the owners  and 
attendants  of  the  farm.  Although  both  
Artificial  Insemination  (AI)  and  natural 
method of breeding system were practiced
 in  the  study  areas,  most  of  the  owners  prefer  
natural  mating  because  their  cows  repeat more 
than two times when inseminated by AI. 

https://www.ncbi.nlm.nih.gov/pubmed/?term=Bolka%20A%5BAuthor%5D&cauthor=true&cauthor_uid=31146689
https://www.ncbi.nlm.nih.gov/pubmed/?term=Gebremedhin%20S%5BAuthor%5D&cauthor=true&cauthor_uid=31146689


East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1 
 

 

In all the farms, there was no regular 
vaccination and deworming practices for the 
common infectious and parasitic diseases, 
respectively.  

Study Methodology 

This research employed both retrospective and 
prospective (i.e. follow-up) studies to generate 
relevant data to attain the aforementioned 
specific objectives. Moreover, serological 
survey was also conducted to estimate the 
prevalence of Bovine Brucellosis. 

Retrospective survey 

Retrospective data was collected from the cow 
level record books kept by the farms (if any) 
and by using pretested semi-structured 
questionnaire (administered in the form of 
interview). Before the commencement of the 
interview, of course to get full co-operation of 
the dairy owners and hence obtain reliable data 
about their animals, thorough explanation was 
made to the respondent on the objectives of the 
study before the start of the interview and record 
exploration. During the interview, the actual 
questions on questionnaire were systematically 
and chronologically presented in Amharic (the 
national language). Accordingly, herd level 
information (housing, feeding, source of feed, 
herd size) and cow level information (parity, 
breed, service used, source of the cow, number 
of service per conception, and history of any 
reproductive disorder on the previous calving) 
were collected and recorded. All the cow level 
information was registered by their ear tag 
number and/ or given name for ease of 
identification. Moreover, the data collectors 
tried to make personal judgment and validation 
on the information given pertaining the 

management and husbandry. To avoid 
ambiguity, the major reproductive problems 
(Namely abortion, dystocia, retained fetal 
membrane (RFM), uterine infection, anoestrous, 
repeat breeder, vaginal prolapse and uterine 
prolapsed) were clearly defined according to the 
literature and explained to respondents.  

Follow-up survey 

During postpartum period, cows were regularly 
examined for the presence of retained fetal 
membrane, any systemic signs, and abnormal 
vaginal discharge. During each visit, rectal 
temperature of cows with rough hair coat, 
depression and reduced appetite was measured 
by digital veterinary thermometers (Microlife 
VT1831; Measurement accuracy of ± 0.1°C). 
Each postpartum cow was visually inspected for 
the presence of any discharge on the vulva, 
perineum or tail. Moreover, after cleaning the 
vulva, a clean and sterile vaginal speculum was 
slowly inserted into the vagina of the cows and 
then the cervix and vagina were thoroughly 
inspected with illumination from a penlight. The 
type and nature of the vaginal discharge was 
differentiated from cows with normal delivery. 
The nature of discharge was classified as clear 
mucus, predominantly clear mucus with flecks 
of pus, mucopurulent (approximately 50% pus 
and 50% mucus), purulent (>50% pus) but not 
foul-smelling, or purulent or red-brown and foul 
smelling according to LeBlanc et al. (2002). 
Retained fetal membrane was defined as failure 
to pass the fetal membrane within 24 h 
postpartum (Kelton et al., 1998). Abortion was 
defined as the expulsion of a dead fetus of 
recognizable size at any stage of gestation 
(Robert, 1986; Ball and Peters, 2004). 
Anoestrus was defined as the failure of the cow 
to show clinical heat signs for 90 days or more 

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East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1 
 

 

after parturition (Arthur et al., 1992; Bekana et 
al., 1994). Moreover, cows or heifers that cycle 
normally and have on clinical abnormality but 
failed to conceive by three or more consecutive 
services were considered as repeat breeder 
(Robert, 1986; Bonneville-Hébert et al., 2011). 

Serological survey 

Blood and serum sample collection 

Approximately 10ml of blood samples were 
collected from the jugular vein of the randomly 
selected cows (800 in total) using plain 
vacationer tubes. Each tube was properly 
labelled with codes and allowed to clot over 
overnight at room temperature by placing 
inclined on a table. On the next morning, the 
sera were separated undisturbed, aliquated in to 
1.8 ml cryo vials, properly labelled, transported 
and stored at -20⁰C in FVM-HU lab. The sera 
were shipped with a cold chain to the National 
Animal Health Diagnostic and Investigation 
Centre NAHDIC), Sebeta, for a better and safe 
storage and serological tests. 

During sample collection, the town, farm name, 
herd size, Cow ID / name, parity, breed, history 
of previous abortion/reproductive disorder and 
current physiological state (viz lactating, dry, 
pregnant) were recorded for all sampled animals 
on a format prepared for the same.  

Serological examination  

In the lab, the sera were exposed for Brucellosis 
serological tests (ID Screen  Brucellosis 
Serum Indirect Multi-species ELISA) as per the 
kits’ instruction (ID.Vet Innovative Diagnostic, 
rue Louis Pasture- Grables, France). Briefly, 
before performing the test, the sera and all 

reagents taken out of the refrigerator and left at 
room temperature for half an hour and 
homogenized by inversion and flicking with 
finger. The serum and controls (positive and 
negative controls), at a dilution rate of 1/20 
were added to microwells coated with Brucella 
abortus LPS. The plates were incubated at 37°C 
in a humid incubator for 60 min and washed 3x 
with washing buffer. Then, 100 μL of the 
conjugate was added to each well and incubated 
again at 37°C and wet for 60 min. Again, 
washes were repeated, and 100 μL of TBM 
(substrate solution) were added, the wells were 
shaken, covered, and incubated at 18-26°C for 
15 min. Finally, the reaction was stopped by 
adding 100 μL of the “stop” solution to each 
well and the results were read using an 
automated ELISA reader with a wavelength of 
450 nm. The test were valid if the mean OD 
value of positive and ratio of positive to 
negative controls were calculated as ODPC > 
0.350 and ODPC/ODNC > 3, respectively. The 
result was interpreted by Sero-positivity 
percentage (S/P %) of ≥120% as positive and ≤ 
110% as negative. 

Data management and analysis 

18

The data obtained from questionnaire and 
follow-up surveys were carefully entered into 
farm and cow-level database Excel files. The 
data were coded and analyzed using Stata 14.2 
window version (StataCorp, College Station, 
TX  USA).  The  association  of  different 
risk-factors  such  as  breed,  management 
system, and methods of  breeding  with over 
all  prevalence  of  reproductive  problems 
were analysed by using χ2 (Chi- square) test 
and value of p<0.05 considered as significant. 



East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1 
 

 

RESULTS  

In general, out of the total 205 cows examined, 
90 cows (43.90%) were having at least one of 
the reproductive disorders identified by either 
questionnaire interview or regular follow up of 
individual cows. Out of 146 cows 
retrospectively and 59 cows prospectively 
assessed for the presence of any reproductive 
disorder, 62 (42.47%) and 28 (47.46%) cows 
had at least one reproductive disorders, 
respectively. Based on questionnaire surrey and 
longitudinal study (follow-up), Retained Fetal 
Membrane, Abortion, Uterine infection, 

Anestrus, Repeat breeding, Dystocia, 
Hypocalcemia, Uterine prolapsed and Vaginal 
prolapsed were the major reproductive problems 
in dairy cows of Wondo Genet district (Table 
1). On questionnaire survey, Retained Fetal 
Membrane and Abortion (12.33% each), 
anestrus (8.22%), and dystocia (4.79%) were the 
leading reproductive problems in dairy farms. 
Whereas, uterine infection (23.73%), Retained 
Fetal Membrane (18.64%), and repeat breeding 
(15.25%) were the leading problems 
encountered during the follow-up period (Table 
1).  

 

Table-1: Table 1: Major reproductive disorders of cows encountered in the study area 

Type of reproductive Disorder  Follow-up (n=59) Retrospective (n=146) Overall (n=205) 

No (%) affected No (%) affected No (%) affected 
Retained Fetal Membrane 11 (18.64) 18 (12.33) 29 (14.15) 
Dystocia 3 (5.08) 7 (4.79) 10 (4.88) 
Uterine infection 14 (23.73) 6 (4.11) 20 (9.76) 
Abortion 6 (10.17) 18 (12.33) 24 (11.71) 
Hypocalcaemia 3 (5.08) 4 (2.74) 7 (3.41) 
Anestrous 5 (8.47) 12 (8.22) 17 (8.29) 
Uterine prolapsed 2 (1.37) 1 (1.69) 3 (1.46) 
Repeat breeder 9 (15.25) 3 (2.05) 12 (5.85) 
Vaginal Prolapse 1 (1.69) 2 (1.37) 3 (1.46) 
Overall (at least one Reproductive Disorder) 28 (47.46) 62 (42.47) 90 (43.90) 

 

Although reproductive disorder is multi-
factorial in nature and influenced by several 
host and environment (management) related 
factors, only the most important and widely 
accepted factors are considered in this study. 
Among the considered host related risk factors, 
only the presence of previous reproductive 

disorder had statistically significant association 
with the occurrence of reproductive disorder 
(p<0.05) (Table 2).  

 

 

 

 

 

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East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1 
 

 

Table- 2. Host Factors associated with the occurrence of major reproductive problems 

Factors   No cows examined Cows affected, No (%) χ2 p value 
Body Condition Score Poor 6 5 (83.3) 3.455 0.175  

Medium 28 12 (42.86) 
  

 
Good 25 11 (44) 

  

Previous rep. performance Poor 21 15 (71.43) 7.514 0.006  
Good 38 13 (34.21) 

  

NSC One 33 15 (45.45) 0.12 0.73 
  ≥Two 26 13 (50) 

  

Parity First  6 3 (50) 2.752 0.432 
  Second 14 4 (28.57) 

  

  Third 14 8 (57.14) 
  

  ≥Fourth  25 13 (52) 
  

Breed/Blood level 50%HF* 21 10 (47.62) 0.850 0.654 
  75%HF 14 8 (57.14) 

  

  87.5%HF 24 10 (41.67) 
  

NSC=number of service per conception, HF=Holstein Friesian 
 

On the other hand, among the considered 

management related risk factors (vis-a-viz 

source of the animal, management type, service 

used, floor type, presence of calving pen and 

contact with dogs) none of them had statistically 

significant association with the occurrence of 

reproductive disorders (Table 3). 

  

 

Table -3. Management Factors associated with the occurrence of major reproductive problems 
Factors   No cows examined Cows affected, No (%) χ2 p value 
Source of the animal Raised in the farm 36 17 (47.2) 0.002 0.964 
  Purchased 23 11 (47.83) 

  

Management Semi- intensive 41 18 (43.9) 0.68 0.41 
  Intensive 18 10 (55.6) 

  

Contact with dogs Yes 38 17 (44.7) 0.317 0.573 
  No 21 11 (52.4) 

  

Floor type Soil 13 9 (69.2) 3.17 0.075 
  Concrete 46 19 (41.3) 

  

Graze Outside Yes 33 13 (39.4) 1.95 0.162 
  No 26  15 (57.7) 

  

Calving pen Yes 31 12 (38.7) 2.005 0.157 
  No 28 16 (57.1) 

  

Service Used Natural 40 9 (47.5) 0.0001 0.992  
AI 19 9 (47.37) 

  

 

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East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1 
 

 

Among the different reproductive disorders, 
abortion and retained fetal membrane showed 
statistically significant association (p<0.05) with 

uterine infection that was expressed either in the 
form of endometritis or metritis (Table 4).  

Table-4. Association of uterine infection with the other reproductive disorders of cows as a 
predisposing factor  
Predisposing 
factors 

Number of 
cows 

Cows with uterine 
infection 

Cows without uterine 
infection 

χ2 p-
value 

RFM 11 7(63.6%) 4(36.4%) 11.9 0.001 
Abortion  6 5(83.3%) 1(16.7%) 13.11 0.000 
Dystocia 3 1(33.3%) 2(66.7%) 0.16 0.688 
Hypocalcemia 3 1(33.3%) 2(66.7%) 0.16 0.688 
RFM=Retained Fetal Membrane 
 

The study further revealed that all the serum 
samples (800) collected from Wondo Genet, 

Hawassa, Wolaita Sodo and Arsi Negelle were 
negative for bovine brucellosis.  

 

DISCUSSION  

The prevalence of reproductive disorder 
recorded by the retrospective study (42.47%) is 
comparable with the studies of Dawit and 
Ahmed (2013) and Hadush et al (2013), who 
reported 40.3% and 44.3% from Kombolcha and 
central Ethiopia, respectively. Based on the 
existing published literatures, the prevalence of 
reproductive disorders in dairy cows, as 
reported by different researchers from different 
geographic locations in Ethiopia, range from 
8.99% to 67.8% (Shiferaw et al., 2005; 
Abreham et al., 2010; Molalegne and Shiv, 
2011; Ayele et al., 2013; Hunduma, 2013; 
Ambaw et al., 2017; Abunna et al., 2018; 
Abdeta and Hailu, 2020). However, the current 
report and of course most of the reports made 
earlier in the country, are quite higher than the 
reports made from abroad (Maruf et al., 2012; 
Elhassen et al., 2015; Khan et al., 2016). This 
variation in prevalence might be due to the 
difference in sample size, study methodology, 
farm management, environmental factors and 

breed of the animals kept in the different farms. 
However, variation in management system that 
is applied in different dairy farms including 
provision of veterinary service, proper feed and 
feeding, housing, hygiene, timely heat detection 
and insemination, implementation of farm 
biosecurity measures and record keeping. 

Among the observed reproductive disorders, 
retained fetal membrane (RFM) was the leading 
problem accounted for a prevalence of 14.15%. 
Similar findings have been reported elsewhere 
by Abreham et al. (2010) from Addis Ababa 
milk shed, Ahmed and Naod (2019) from Jimma 
town and Ayele et al. (2013) from Wolaita Sodo 
town. Although RFM occurs more frequently in 
dairy farms of the developing countries, it is still 
an economically important disease of US dairy 
industry and affects approximately 7.8% (range: 
1.3 to 39.2%) of the dairy cows (USDA, 2009; 
Qu et al., 2014). The presence of RFM greatly 
increases the risk of metritis and endometritis 
(LeBlanc, 2008) because of tissue 
decomposition, compromised immunity and 

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East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1 
 

 

patent cervical canal with a concomitant 
ascending infection. In line with this, the current 
study also showed that cows with RFM 
developed uterine infection more significantly 
than those without RFM.  

Studies suggest that although the causes of 
abortion are both infectious and non-infectious 
in origin, in most cases where a diagnosis is 
reached, the cause is infectious (Cabell, 2007). 
The attempt made in the current study to 
estimate the prevalence of bovine brucellosis in 
4 selected towns including Wondo Genet 
revealed that brucellosis is not prevalent in the 
area and hence could not be blamed for abortion 
cases at least in the study areas. The current 

finding is concordant with the previous studies 
conducted by Belihu (2002) and Asmare et al 
(2013) who couldn’t find positive reactors in 
dairy farms of the Addis Ababa area and  from 
central Ethiopia (Adama) and northern Ethiopia 
(Mekele and Gondar), respectively. These 
findings strongly suggest the presence of 
infectious and/or noninfectious causes other 
than bovine brucellosis that should be 
considered the moment other similar serological 
surveys are planned in the future.  

22

Uterine infection, in the form of clinical 
endometritis / metritis, was the third commonly 
encountered reproductive disorder in the area 
(9.76%). This problem is also reported by 
other researchers from different parts of the 
country with prevalence ranging from 1.2% in 
Bedelle (Esheti and Moges, 2014) to 16.9% in 
Ada’a district (Molalegne and Shiv, 2011). 
According to Lewis (1997), as large as 40% of 
the postpartum cows in some herds abroad may 
be diagnosed with, and treated for, uterine 
infections. Variation among studies in the 
prevalence of uterine infection could be 
emanated from the difference in the diagnostic 
methods used, the classification of the uterine 
infections, the postpartum period during which 
the infections were detected, the parity of the 
cows, the general characteristics of the cows, or 
the herd management practices at large. 
Although the risk factors for uterine infections 
are well established (LeBlanc et al., 2002), 
prevention of uterine infections is usually 
difficult because of the presence of nonspecific 
bacteria on the lower genitalia and all over the 
cow’s environment (Lewis, 1997). However, 
most researchers argue that attention to 
sanitation and periparturent hygiene, 
particularly during calving, may be the best and 
wise attempt  

Abortion, the second most frequently 
encountered reproductive disorder in the current 
study (11.7%), was also reported as the second 
leading reproductive disorder in most parts of the 
country (Molalegne and Shiv, 2011; Abunna et 
al., 2018; Abdeta and Hailu, 2020 ). Based on 
the retrospective and/or follow-up studies 
conducted earlier, the prevalence of abortion in 
dairy cows in Ethiopia ranges from 0.63% in 
Wolaita Sodo (Ayele et al., 2013) to 28.9% in 
Adea Berga Dairy farm, West Shewa (Siyoum 
et al., 2016). Such variation in the prevalence of 
abortion among these studies could be partly 
explained by the difference in host and 
management related risk factors and the 
presence of different etiological factors for the 
occurrence of abortion. Regardless of the cause, 
most cases of abortions in cows are followed by 
uterine infection and hence connected with 
delayed uterine involution in the postpartum  
period (Getnet et al., 2018). The current study 
also showed that over 80% of the cows with 
abortion later developed uterine infection.  



East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1 
 

 

The effort made to assess the association of 
different host and management related risk 
factors with the occurrence of the reproductive 
disorders revealed that only previous history of 
reproductive performance showed statistically 
significant association (p<0.05). This clearly 
showed that cows with poor reproductive 
performance in their previous reproductive 

cycle are more likely to develop at least one of 
the reproductive disorders in their subsequent 
pregnancies. This could be partly explained by 
the likelihood of development of permanent 
changes (functional and/or mechanical damages 
like scaring and stenosis) on the uterus and 
ovaries following most reproductive disorders 
(Bonneville-Hébert et al., 2011). The absence of 
association with the other considered risk 
factors need to be proved further with a larger 
sample size preferably on a wider geographic 
area. 

CONCLUSION 

This study revealed the presence of a serious 
reproductive disorders in cows of  the study 
areas, Retained Fetal Membrane, Abortion, 
Uterine infection and Anestrus were the leading 
reproductive disorders followed by others. 
Among the considered host and management 
related risk factors, only the presence of 
previous reproductive disorder had statistically 
significant association with the occurrence of 
the problem. The serological survey 
demonstrate that brucellosis was not a problem 
in area including Hawassa, Wolaita Sodo and 
Arsi Negelle towns. 

Since the causes of reproductive disorders are 
multifactorial, laboratory based studies should 
be conducted to identify the underlined causes 
of these problems in different parts of the 
country. Meanwhile, awareness creation to farm 
owners/attendants to improve their farm 
management system through proper housing and 
feeding, accurate and timely heat detection and 
insemination, regular consultation with animal 
health and production professionals, selection of 
feasible breeding method, maintaining hygiene 
of the cow and its environment and strict farm 

23

Anoestrus (8.3%) and repeat breeding (5.85%) 
were the other reproductive disorders 
encountered in the study area quite frequently. 
Unlike the current findings, these reproductive 
disorders, particularly anoestrus, are the leading 
problem in most parts of the country including 
Borena zone (Benti and Zewdie, 2014), Desie 
and Kombolcha (Ambaw et al., 2017), Hosanna 
town (Adane et al., 2014), Nekemte town 
(Abdeta and Hailu, 2020), Ada’a district (Esheti 
and Moges, 2014) and Dawro zone (Bizuayehu 
and Wale, 2016). Some studies from abroad 
including Khan et al. (2016) from India, 
Elhassan et al. (2015) from Sudan and Maruf et 
al. (2012) from Bangladish also indicated that 
these problems are the leading among other 
reproductive disorders. Although the causes and 
pathogenesis of anoestrus and repeat breeding 
are multifactorial and beyond the scope of this 
research article to discuss, both problems can 
partly be the aftermath of other interrelated 
reproductive disorders mainly dystocia, 
abortion, retained fetal membrane and uterine 
infections. Most of the owners mentioned that 
anoestrus and repeat breeding are the major 
reason for the culling of cows followed by lack 
of space and feed. In line with this, Agarwal et 
al. (2005) and Hadley et al. (2006) also 
conclude that failure to resume to cyclicity and 
timely conceive are the major reasons for 
economic losses and why cows are culled in 
most dairy farms of the globe.  



East Afr. J. Biophys. Comput. Sci., Vol. 2, Issue 1 
 

 

biosecurity can significantly minimize the 
occurrence of these problems and associated 
economic losses in the dairy farms of the area. 
 
Acknowledgment  
We are grateful to all technical assistants in the 
bacterial serology laboratory of the National 
Animal Health Diagnostic and Investigation 
Center (NAHDIC), for their support during 
serological test. We also thank all owners or 
managers of the dairy farms included in the 
study for their permission and collaboration 
during the study period. 

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26


	INTRODUCTION
	EXTENSION OF THE MODIFIED MODEL INTO AN OPTIMAL CONTROL
	Optimal protection and hospitalization using modified model
	Existence of an optimal control
	The Hamiltonian and optimality system

	Numerical simulations of optimal control problem
	Optimal control comparisons and strategies

	CONCLUSION
	INTRODUCTION
	INTRODUCTION

