ABSTRACT
This study presents results on effect of a combination of bismuth subnitrate teat canal sealant (Boviseal®) and the antibiotic Ampicillin + Cloxacillin (Bovaclox® DC) when used during the dry period on occurrence of mastitis 100 days post-calving. The specific objectives of this study were: to determine the effect of Boviseal ® teat canal sealant in combination with Bovaclox ® DC in control of dairy cow mastitis 100 days after calving; to determine bacterial pathogens causing mastitis in the selected farms and to determine risk factors associated with mastitis in dairy cows. This controlled field trial was carried out in two dairy farms in Kenya: Chemusian Farm in Nakuru County and Gicheha Farm in Kiambu County. A total of 156 dairy cows were sampled during the dry period for use in the study. They were randomly placed into either of the two study groups: Control group that received the antibiotic -Bovaclox® DC and the Test group that received the Bovaclox® DC followed by an internal teat sealant- Boviseal®. The cows were followed during the entire dry period (60 days to calving) and 100 days post-calving for development of mastitis. Cows in the control group were more susceptible to mastitis 100 days post-calving compared to cows in the treatment group (P<0.001, RR=4.4, OR=17.7). Coagulase negative Staphylococci (CNS) were the most common pathogens isolated from mastitic milk at 34.6 % followed by Micrococcus spp. (9.0%), Streptococcus agalactiae (3.8%), Staphylococcus aureus (1.9%) and Escherichia coli (0.6%). A multiple logistic regression at P≤0.05 showed that cows in Gicheha farm whose barn floor was earthen, those cows in the control group and hindquarters were risk factors for mastitis (RR=1.5, 4.4 and 1.18 respectively). The study thus recommends the use of Bovaclox® DC - Boviseal® dry cow combination and maintenance of good hygienic practices in animal barns and instruments of milking for control of bovine mastitis.
Table of Contents
Declaration ii
Dedication iii
ACKNOWLEDGEMENT iv
LIST OF TABLES viii
LIST OF FIGURES x
LIST OF PLATES xi
ABSTRACT xii
CHAPTER 1: INTRODUCTION
1.1 Background to the study 1
1.2 Control measures for bovine mastitis 2
1.2 Problem statement 3
1.3 Justification 3
1.4 Objectives 4
1.4.1 General objective 4
1.4.2 Specific objectives 4
1.5 Hypothesis 4
CHAPTER 2: LITERATURE REVIEW
2.1 Aetiology of mastitis 5
2.2 Classification of mastitis 5
2.3 Epidemiology of bovine mastitis 6
2.4 Clinical signs of mastitis 7
2.5 Diagnosis of mastitis 7
2.5.1 Physical examination 7
2.5.2 California Mastitis Test (CMT) 8
2.5.3 Somatic cell count 9
2.5.4 Polymerase chain reaction (PCR) 9
2.5.5 Bacterial culture 10
2.5.6 White slide test 10
2.6 Control of mastitis 10
2.6.1 Management 10
2.6.2 Antibiotic containing dry cow therapy 11
2.6.3 Culling of mastitic cows 11
2.6.4 Internal teat sealants during dry period 11
CHAPTER 3: MATERIALS AND METHODS
3.1 Study area 13
3.2 Study design 14
3.2.1 Sample size determination and allocation into study groups 14
3.3 Criteria for cow selection into the study 15
3.4 Udder and hind leg hygiene scoring 16
3.5 Administration of reference and test products 18
3.6 Animal follow-up 18
3. 7 Milk sample collection, transportation 19
3.8 Culture and identification of bacteria 19
3.9 Data management and analysis 20
CHAPTER FOUR
4.0 RESULTS 21
4.1 Herd demographics and profiles 21
4.2 Prevalence of mastitis 22
4.3 Mastitis cases in the treatment and control groups in Chemusian and Gicheha Farms in 2017/2018 23
4.3.1 Overall mastitis 23
4.3.2 Clinical mastitis 25
4.3.3 Subclinical mastitis 27
4.4 Quarter level prevalence of mastitis 28
4.4.1 Chemusian farm 28
4.4.2 Gicheha farm 30
4.5 Factors influencing occurrence of bovine mastitis 32
4.5 Bacterial pathogens causing mastitis 34
CHAPTER FIVE
5.0 DISCUSSION 37
CHAPTER SIX
6.0 CONCLUSIONS AND RECOMMENDATIONS 40
6.1 Conclusions 40
6.2 Recommendations 40
REFERENCES 41
APPENDICES 57
Appendix 8.1: Dry cow preparations used in the study 57
Appendix 8.2: Pictures of Lab Work 58
Appendix 8.3: Farm and herd characteristics and findings on mastitis for Chemusian and Gicheha farms as at 2017/2018 61
LIST OF TABLES
Table 2.5.2 Summary of California Mastitis Test scores and their interpretation 9
Table 4.1 Herd profile in Chemusian farm in 2017/2018 21
Table 4.2 Herd profile in Gicheha farm in 2017/2018 22
Table 4.3 Number of cases and percentage of various categories of bovine mastitis in Chemusian and Gicheha Farms in 2017/2018 23
Table 4.4a Relationship between overall mastitis and type of treatment used in Chemusian Farm in 2017/2018 24
Table 4.4b Relationship between overall mastitis and type of treatment used in Gicheha Farm in the year 2017/2018 25
Table 4.5a Relationship between clinical mastitis and type of treatment used in Chemusian Farm in the year 2017/2018 26
Table 4.5b Relationship between clinical mastitis and type of treatment used in Gicheha Farm in the year 2017/2018 26
Table 4.6a Relationship between subclinical mastitis and type of treatment used in Chemusian Farm in 2017/2018 27
Table 4.6b Relationship between subclinical mastitis and type of treatment used in Gicheha Farm in the year 2017/2018 28
Table 4.7a Distribution of CMT scores in various quarters for cows in Chemusian Farm in 2017/2018 29
Table 4.7b : Comparison of occurrence of mastitis between hind and forequarters for cows in Chemusian Farm in 2017/2018 30
Table 4.8a : Distribution of CMT scores in various quarters for cows in Gicheha Farm in 2017/2018 31
Table 4.8b : Comparison of occurrence of mastitis between hind and forequarters for cows in Gicheha Farm in 2017/2018 32
Table 4.9a showing univariate analalysis of various factors influencing occurrence of mastitis in Chemusian and Gicheha farms in 2017/2018 33
Table 4.9b showing the multiple logistic regression model of factors influencing occurrence of mastitis 34
Table 4.10a : Table showing proportion of various bacteria isolated from mastitic milk from Chemusian and Gicheha Farms in 2017/2018 35
Table 4.10b : Table showing bacterial distribution between Test and Control groups in Chemusian and Gicheha Farms 36
LIST OF FIGURES
Figure 3.1 Map showing the location of study areas, Chemusian and Gicheha Farms in Kenya. 14
Figure 3.2 Udder cleanliness score. Picture number corresponds to the score for udder and leg by Schreiner & Ruegg, 2010b 17
LIST OF PLATES
Plate 8.1a : Test product,Bismuth subnitrate (Boviseal®)) tube 57
Plate 8.1b : Boviseal® pressed from the tube 57
Plate 8.1c : Standard product, Ampicillin+Cloxacillin (Bovaclox®) 57
Plate 8.2a : Positive sample of Streptococcus agalactiae (CAMP positive) on Blood Agar 58
Plate 8.2b : Positive samples for various bacteria for storage 59
Plate 8.2c : Catalase test for Staphylococcus aureus 60
CHAPTER 1
INTRODUCTION
1.1 Background to the study
The livestock industry contributes to the growth of the economy of not only Kenya, but the entire world (Muthami, 2011; Mihret et al., 2017). Kenya has approximately 17.5 million cattle, with exotic breeds being 3.5million and indigenous breeds 14million (KNBS, 2010). The growth of the dairy sector is limited by various factors including; livestock diseases, poor access to the market, inadequate veterinary and livestock extension services providers and poor nutrition among others (Karanja, 2003; Munyori and Karanja, 2014). One of the major production diseases affecting the dairy cattle is mastitis (Barlow, 2011; Gitau et al., 2014; Gomes and Henriques, 2016b).
Mastitis is defined as inflammation of the udder, mainly due to infection. In the dairy industry, mastitis is the most costly production disease (Viguier et al., 2009; Gomes and Henriques, 2016a). The disease is caused by various pathogens, ranging from bacterial, fungal to viral organisms. Of major importance are the bacteria, both gram positive such as Staphylococcus spp. and Streptococcus spp. and gram negative such as the coliforms such as Escherichia coli ( Blowey and Edmondson, 2010; Girma et al., 2012; Belayneh et al., 2013).Viral infections such as foot and mouth disease and bovine herpes directly cause mastitis or erode the skin of the udder and predispose it to secondary bacterial infections resulting into mastitis (Wellenberg et al., 2002). Based on clinical features, mastitis can be classified as either clinical or subclinical (Fox, 2009; Mdegela et al., 2009). Mastitis can also be classified either as environmental or contagious mastitis (Fox, 2009; National Mastitis Council, 2015). Environmental mastitis is caused by pathogens commonly isolated from the environment of the cow, which includes milking machine, barn floor, soil, walkways, pasture and any surface with which the cow may be in contact. Organisms that cause environmental mastitis include Staphylococcus species (excluding Staphylococcus aureus), Streptococcus species (excluding Streptococcus agalactiae), coliforms such as Escherichia coli and Enterobacter species, Pseudomonas, Proteus, Yeast and Prototheca among others. Contagious mastitis is caused by pathogens that spread from cow to cow. These pathogens primarily inhabit the udder and teat of cows. The major pathogens responsible for this type of mastitis are Streptococcus agalactiae, Corynebacterium bovis, Staphylococcus aureus and Mycoplasma (Gonzalez and Wilson., 2003; Breen et al., 2009) Factors that predispose cattle to mastitis include breed, increased milk production, increase in parity, poor hygienic status of the cow environment among others (Breen et al., 2009; Ramírez et al., 2014)
Mastitis not only reduces milk quality and quantity at lactation, but may occasionally result in fatalities of the affected animal (Gomes and Henriques., 2016a). Of greater importance is the zoonotic threat of some bovine mastitis causing microorganisms such as Mycobacterium tuberculosis, Staphylococcus aureus and Listeria monocytogenes among others (Mwinyelle and Alhassan, 2014; Vishnupriya et al., 2014; Sharma et al., 2017).
1.2 Control measures for bovine mastitis
Several interventions have been applied in the control, prevention and treatment of mastitis in dairy cows. One of the most important preventive and control measures is proper hygiene of the cow environment (Lam et al., 2013). The most common approach to treatment and prevention of mastitis worldwide is through the use of antimicrobials such as tetracyclines, sulphonamides and lincosamides among others (Oliver and Murinda, 2012). Due to prolonged use and misuse of these agents, antimicrobial resistance has increased in both livestock and humans (Oliver and Murinda, 2012; WHO, 2014). This fact has called for the use of more environmentally friendly inventions such as vaccines, internal teat sealants, recombinant mucolytic proteins e.g. lysostaphin and nanoparticles (Sankar, 2016).
The use of internal teat sealant containing bismuth subnitrate in controlling bovine mastitis has been practised in various jurisdictions worldwide. Several studies have shown its efficacy in reducing prevalence of mastitis in dairy cows. The product is efficacious against clinical and subclinical mastitis as well as reducing the level of milk somatic cell counts (Cook et al., 2005; Compton et al., 2014). Rabiee and Lean (2013) demonstrated that use of bismuth subnitrate alone or in combination with antibiotic dry cow therapy pre-calving reduces incidence of clinical mastitis post-calving by 29% and 48% respectively.
There are no documented studies in Kenya with regard to the use of bismuth subnitrate or its combination with an antibiotic containing dry cow intramammary in prevention and control of mastitis. This study investigated the effect of combining an antibiotic-containing dry cow intramammary and an internal teat sealant in controlling dry cow mastitis and mastitis up to 100 days post-calving.
1.2 Problem statement
Usually the teat canal remains patent during the early dry period, regardless of antibiotic use during this period. Provided the canal is open, pathogens easily enter the udder usually resulting into an infection.
1.3 Justification
Bismuth subnitrate closes the teat canal during the dry period thus limiting entry and colonisation of mastitis causing pathogens in the udder. This greatly reduces incidence of both dry cow and post-calving mastitis (Woolford et al., 1998).The treatment of clinical mastitis using intramammary (IMM) tubes usually takes 3-5 days consecutively. This means that a total of 12 to 20 tubes are used during this period. With the cost of each IMM tube being Ksh. 100-200 (USD 1-2) it implies that a farmer spends Ksh. 1200-4000 (12-40 USD) to acquire these tubes only. The cost of bismuth subnitrate tubes is Ksh. 400 (4 USD) for four tubes and Ksh. 400-600 (4-6 USD) for four tubes of dry therapy containing Ampicillin and Cloxacillin. These latter products can be administered by farmers thus lowering the professional charges demanded by vets when they treat mastitis cases. After calving, the teat sealant is milked from the teat either by the farmer or the calf.
1.4 Objectives
1.4.1 General objective
To demonstrate the benefit of bismuth subnitrate teat canal sealant in combination with Ampicillin+Cloxacillin dry cow therapy in controlling bovine mastitis in selected farms in Kenya.
1.4.2 Specific objectives
1. To determine the effect of bismuth subnitrate teat canal sealant in combination with Ampicillin+Cloxacillin dry cow therapy in control of dairy cow mastitis 100 days after calving.
2. To determine bacterial pathogens causing mastitis in the selected farms.
3. To determine risk factors associated with mastitis in dairy cows in the selected farms
1.5 Hypothesis
A combination of bismuth subnitrate teat canal sealant and Ampicillin-Cloxacillin dry cow therapy reduces the prevalence of mastitis 100 days post-calving in dairy cows.
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