Infectious abortion and associated risk factors in dairy cattle farms in Nakuru district, Kenya

139 Pages·2014·0.77 MB·English

by  Tequiero Abuom Okumu

INFECTIOUS ABORTION AND ASSOCIATED RISK FACTORS IN
DAIRY CATTLE FARMS IN NAKURU DISTRICT, KENYA

TEQUIERO ABUOM OKUMU
BVM, M.SC. (University of Nairobi)

A thesis submitted in fulfilment of the requirements for the degree of
Doctor of Philosophy (Clinical Studies)

University of Nairobi
Faculty of Veterinary Medicine
Department of Clinical Studies

2014
I
DECLARATION
This thesis is my original work and has not been presented for a degree in any other
university
__________________________________________
Tequiero Abuom Okumu, BVM, MSc.
This thesis has been submitted for examination with our approval as university
supervisors
Supervisors
Prof. NJENGA M. J. (B.V.M., M Sc., Ph.D.)
Signed: ______________________Date: _______________
Prof. WABACHA J. K. (B.V.M., M Sc., Ph.D.)
Signed: ______________________Date: _______________
DR. TSUMA V. T. (B.V.M., Dip Anim. Reprod., FRVCS., Ph.D.)
Signed: ______________________Date: _______________
DEPARTMENT OF CLINICAL STUDIES
UNIVERSITY OF NAIROBI
Prof. JOHN VANLEEUWEN ( D.V.M., M.Sc., Ph.D.)
Signed: ________________________Date _________________
ATLANTIC VETERINARY COLLEGE,
UNIVERSITY OF PRINCE EDWARD ISLAND
II
DEDICATION

To

My wife Damaris and my family, The Okumu’s
III
TABLE OF CONTENTS
DECLARATION ............................................................................................................................... II
DEDICATION .............................................................................................................................. III
TABLE OF CONTENTS .................................................................................................................... IV
LIST OF TABLES .............................................................................................................................. IX
LIST OF FIGURES ............................................................................................................................. XI
ACKNOWLEDGEMENTS .............................................................................................................. XII
LIST OF ABBREVIATIONS .......................................................................................................... XIV
ABSTRACT ............................................................................................................................ XV
CHAPTER ONE ........................................................................................................................... - 1 -
1. GENERAL INTRODUCTION ......................................................................................... - 1 -
CHAPTER TWO ........................................................................................................................... - 3 -
2. LITERATURE REVIEW ................................................................................................. - 3 -
2.1 Bovine viral diarhoea (BVD) ............................................................................................ - 6 -
2.2 Brucellosis ......................................................................................................................... - 9 -
2.3 Neosporosis ..................................................................................................................... - 10 -
2.4 Hypothesis....................................................................................................................... - 13 -
2.5 Overall objective ............................................................................................................. - 13 -
2.6 Specific objectives .......................................................................................................... - 13 -
2.7 Justification ..................................................................................................................... - 14 -
CHAPTER THREE ........................................................................................................................ - 15 -
3 MATERIALS AND METHODS .................................................................................... - 15 -
3.1 Study area ........................................................................................................................ - 15 -
3.2 Selection of study farms and animals ............................................................................. - 16 -
3.3 Study design .................................................................................................................... - 17 -
3.3.1 Prevalence survey .................................................................................................................. - 17 -
3.3.2 Prospective study ................................................................................................................... - 17 -
IV
3.3.3 Sample analysis ..................................................................................................................... - 19 -
3.3.3.1 Bovine viral diarrhoea virus (BVDV) ................................................................................ - 20 -
3.3.3.2 Brucella abortus ................................................................................................................. - 22 -
3.3.3.3 Neospora caninum .............................................................................................................. - 24 -
3.3.3.4 Sampling of dogs for Neospora caninum ........................................................................... - 25 -
3.4 Data management ............................................................................................................ - 25 -
3.4.1 Statistical analysis ................................................................................................................. - 26 -
CHAPTER FOUR ......................................................................................................................... - 28 -
4 SEROPREVALENCE AND RISK FACTORS OF BOVINE VIRAL DIARRHOEA
VIRUS, Brucella abortus AND Neospora caninum ANTIBODIES IN DAIRY
CATTLE HERDS IN NAKURU DISTRICT, KENYA ................................................. - 28 -
4.1 Introduction ..................................................................................................................... - 28 -
4.1.1 Bovine Viral Diarrhoea ......................................................................................................... - 29 -
4.1.2 Brucellosis ......................................................................................................................... - 31 -
4.1.3 Neosporosis ......................................................................................................................... - 32 -
4.2 Materials and Methods .................................................................................................... - 34 -
4.2.1 Study area ......................................................................................................................... - 34 -
4.2.2 Selection of study farms and animals .................................................................................... - 34 -
4.2.3 Data and sample collection. ................................................................................................... - 34 -
4.3 Sample handling and laboratory analysis ........................................................................ - 34 -
4.4 Data management and analysis ....................................................................................... - 35 -
4.4.1 Data management .................................................................................................................. - 35 -
4.4.2 Statistical analysis ................................................................................................................. - 35 -
4.5 Results ......................................................................................................................... - 35 -
4.5.1 Descriptive statistics .............................................................................................................. - 35 -
4.5.1.1 Response rate and number of animals selected into the study............................................ - 35 -
4.5.1.2 Animal variables ................................................................................................................. - 36 -
4.5.1.3 Feeding system ................................................................................................................... - 36 -
V
4.5.1.4 Breeding methods ............................................................................................................... - 36 -
4.5.1.5 Vaccination ......................................................................................................................... - 37 -
4.5.1.6 Reproductive history .......................................................................................................... - 37 -
4.5.1.7 Seroprevalence results ........................................................................................................ - 37 -
4.5.2 Disease variables ................................................................................................................... - 37 -
4.5.2.1 BVDV ......................................................................................................................... - 37 -
4.5.2.2 Neospora caninum .............................................................................................................. - 38 -
4.5.2.3 Brucella abortus ................................................................................................................. - 39 -
4.5.2.4 Interrelationship between diseases ..................................................................................... - 41 -
4.5.2.5 Regression analysis of risk factors ..................................................................................... - 41 -
4.6 Discussion ....................................................................................................................... - 43 -
4.7 Conclusion and recommendations .................................................................................. - 48 -
CHAPTER FIVE ......................................................................................................................... - 49 -
5 SEROEPIDEMIOLOGICAL SURVEY OF Neospora caninum AND ITS RISK
FACTORS IN FARM DOGS IN NAKURU DISTRICT, KENYA ............................... - 49 -
5.1 Introduction ..................................................................................................................... - 49 -
5.2 Materials and methods .................................................................................................... - 51 -
5.2.1 Study area ......................................................................................................................... - 51 -
5.2.2 Farm and animal selection ..................................................................................................... - 51 -
5.2.3 Sample collection, handling, and laboratory analysis ........................................................... - 51 -
5.3 Data collection, management and analysis ..................................................................... - 52 -
5.3.1 Analytical statistics ................................................................................................................ - 53 -
5.4 Results ......................................................................................................................... - 53 -
5.4.1 Descriptive statistics .............................................................................................................. - 53 -
5.4.2 Chi-squared analyses of risk factors ...................................................................................... - 54 -
5.4.3 Regression analysis of risk factors ........................................................................................ - 56 -
5.5 Discussion ....................................................................................................................... - 56 -
VI
CHAPTER SIX ......................................................................................................................... - 60 -
6 THE EFFECT OF BOVINE VIRAL DIARRHOEA VIRUS, Brucella abortus AND
Neospora caninum ON THE INCIDENCE OF ABORTION/FOETAL LOSS IN
DAIRYCATTLE HERDS IN NAKURU DISTRICT, KENYA .................................... - 60 -
6.1 Introduction ..................................................................................................................... - 60 -
6.2 Materials and methods .................................................................................................... - 64 -
6.2.1 Selection of study farms and animals .................................................................................... - 64 -
6.2.2 Sample handling and laboratory analysis .............................................................................. - 64 -
6.3 Statistical analysis ........................................................................................................... - 65 -
6.3.1 Descriptive statistics .............................................................................................................. - 65 -
6.3.2 Analytical statistics ................................................................................................................ - 66 -
6.4 Results ......................................................................................................................... - 67 -
6.4.1 Descriptive statistics .............................................................................................................. - 67 -
6.4.1.1 Animals selected and monitored in the study ..................................................................... - 67 -
6.4.1.2 Animal variables ................................................................................................................. - 67 -
6.4.1.3 Location ......................................................................................................................... - 67 -
6.4.1.4 Feeding system ................................................................................................................... - 67 -
6.4.1.5 Breeding methods ............................................................................................................... - 68 -
6.4.1.6 Reproductive history .......................................................................................................... - 68 -
6.4.2 Abortion incidence ................................................................................................................ - 68 -
6.4.2.1 Univariable associations with abortion............................................................................... - 69 -
6.4.2.2 Stage of foetal loss.............................................................................................................. - 72 -
6.4.2.3 Incidence rates of NC, BVD and BA ................................................................................. - 73 -
6.4.2.4 Infections vs foetal loss ...................................................................................................... - 73 -
6.4.3 Regression analysis ............................................................................................................... - 74 -
6.5 Discussion ....................................................................................................................... - 75 -
CHAPTER SEVEN ........................................................................................................................ - 78 -
VII
7 AN ASSESSMENT OF THE KNOWLEDGE, ATTITUDES AND PRACTICES
RELATED TO BOVINE ABORTION AND FOETAL LOSS AMONG ANIMAL
HEALTH SERVICE PROVIDERS IN NAKURU DISTRICT, KENYA ...................... - 78 -
7.1 Introduction ..................................................................................................................... - 78 -
7.2 Materials and methods .................................................................................................... - 80 -
7.2.1 Study area and population ..................................................................................................... - 80 -
7.2.2 Data collection ....................................................................................................................... - 80 -
7.2.3 Data management and analysis ............................................................................................. - 81 -
7.2.3.1 Data management ............................................................................................................... - 81 -
7.2.3.2 Descriptive statistics ........................................................................................................... - 81 -
7.2.3.3 Analytical statistics ............................................................................................................. - 81 -
7.3 Results ......................................................................................................................... - 82 -
7.3.1 Descriptive statistics .............................................................................................................. - 82 -
7.3.2 Comparison of the level of training with knowledge and practices on bovine abortion ....... - 83 -
7.3.3 Comparison of the years of experience against perceptions and management of bovine
abortion ......................................................................................................................... - 87 -
7.4 Discussion ....................................................................................................................... - 90 -
CHAPTER EIGHT ......................................................................................................................... - 95 -
8 CONCLUSIONS AND RECOMMENDATIONS ......................................................... - 95 -
REFERENCES ......................................................................................................................... - 97 -
APPENDICES - 118 -
APPENDIX 1 FARMERS’ SURVEY QUESTIONNAIRE ........................................................ - 118 -
APPENDIX 2 VETERINARIANS AND PARAVETERINARIANS SURVEY
QUESTIONNAIRE ...................................................................................................... - 120 -
APPENDIX 3 INDIVIDUAL ANIMAL FOLLOW-UP RECORD ............................................ - 121 -
VIII
LIST OF TABLES
Table 4.1 Descriptive statistics and univariable associations between seropositivity to
BVDV, NC and BA their risk factors in among dairy cattle in Nakuru District,
Kenya, 2010……………………………………………...………………...- 41 -
Table 5.1 Descriptive statistics and univariable association between seropositivity for
Neospora caninum and epidemiological data for 84 dogs on 53 dairy farms in
Nakuru District, Kenya in 2010 ..................................................................... - 55 -
Table 6.1 Distribution of foetal loss (n=31) by parity in dairy cattle farms in Nakuru
District, Kenya in 2010-2011 ......................................................................... - 70 -
Table 6.2 Stage of gestation of foetal loss (n=31) in 260 dairy cattle in Nakuru District,
Kenya in 2010-2011 ....................................................................................... - 72 -
Table 6.3 Kaplan-Meier output on stage/time of foetal loss (n=31) in 260 dairy cattle
herds in Nakuru District, Kenya ..................................................................... - 72 -
Table 6.4 Distribution of infections associated with foetal loss (n=31) in 260 dairy cattle
in Nakuru District, Kenya, 2010-2011 ........................................................... - 74 -
Table 6.5 Multivariable regression analysis of risk factors for foetal loss (n=31) in 260
dairy cattle in Nakuru District, Kenya............................................................ - 74 -
Table 5.1 Descriptive statistics and univariable association between seropositivity for
Neospora caninum and epidemiological data for 84 dogs on 53 dairy farms in
Nakuru District, Kenya in 2010……………………………………………- 56 -
IX
Table 6.1 Distribution of foetal loss (n=31) by parity in dairy cattle farms in Nakuru
District, Kenya in 2010-2011…… ................................................................ .- 71 -
Table 6.2 Stage of gestation of foetal loss (n=31) in 260 dairy cattle in Nakuru District,
Kenya in 2010-2011………………………………………………………- 73 -
Table 6.3 Kaplan-Meier output on stage/time of foetal loss (n=31) in 260 dairy cattle
herds in Nakuru District, Kenya…………………………………………- 73 -
Table 6.4 Distribution of infections associated with foetal loss (n=31) in 260 dairy cattle
in Nakuru District, Kenya, 2010-2011……………………………..………- 75 -
Table 6.5 Multivariable regression analysis of risk factors for foetal loss (n=31) in 260
dairy cattle in Nakuru District, Kenya…………………………………….- 75 -
Table 7.1 Distribution of knowledge, attitudes and practices on bovine abortion by level
of training among animal health service providers in Nakuru District, 2010- 86-
Table 7.2 Distribution of knowledge, attitudes and practices on bovine abortion by years
of practicing experience among animal health service providers in Nakuru
District, 2010…………………..…………………………………………..- 89 -

X