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Animal and herd classification
Selected herds were visited once each between July, 2008 and June, 2009. Herd and individual animal data collection, and animal sampling were done during this visit. All the postpubertal bulls, and postpubertal heifers and cows were sampled in each selected herd. A postpubertal bull was defined as a bull that had been successfully mounting other cows or heifers by achieving intromission. They weighed approximately 200 kg or above. A postpubertal heifer was a female that had been observed exhibiting oestrus or standing to be mounted by a bull and on trans-rectal examination, they typically have either of the functional structures i.e corpus luteum or follicle on their ovaries. They were weighing about 200 kg. Four management systems were encountered during the study. The pastoral management system was characterized by cattle grazing on fallow land close to the place of settlement of the owners during the rainy season but covering long distances, some even migrating, during the critical period of the dry season in search of natural pasture. Agro-pastoral management was characterized by cattle grazing locally and supplementation with mostly crop residues particularly during the dry and pre-rainy seasons. Commercial management systems were organized farms that were usually fenced with paddocked, improved pastures and concentrate provided as supplementary feeds. Zero-grazing systems were farms in which the cattle were confined or even tethered with restricted movement and feed was provided.
Reproductive disorders and hygroma
Two classes of reproductive disorders were determined in this study. The first consisted of reproductive disorders observed through trans-rectal examination, with a prevalence of 1.6%. A total of 69 animals were diagnosed with anatomical malformations of the genitalia and foetuses as shown in Table 5.5. The second was the occurrence of reproductive disorders at the herd level from reports or records of owners. Prevalence of the latter ranged from repeat breeder with the highest prevalence of 53.1%, to orchitis/epididymitis with a prevalence of 12.1% (Table 5.5). Hygroma occurred in 23.2% of herds. Abortion, retained afterbirth, stillbirth, repeat breeder, orchitis/epididymitis and hygroma were significantly positively associated with the occurrence of both brucellosis and campylobacteriosis (P < 0.01). The birth of weak calves or calf mortality, and pyometra were significantly associated with brucellosis only (P < 0.01).
Chapter 1 Introduction and literature review
Background
Productivity and reproductive performance of cattle
Cattle reproductive performance in Nigeria
Measures of reproductive performance
Infectious reproductive diseases of cattle
Brucellosis
Campylobacteriosis Trichomonosis
Infectious reproductive diseases of cattle in Nigeria and other African countries
Problem statement
Study objectives and outline of the thesis
Chapter 2 A large seroprevalence survey of brucellosis in cattle herds under diverse production systems in northern Nigeria
Abstract
Introduction
Materials and Methods
Selection of study states
Sample size
Survey design
Demographic data and sample collection
Screening using Rose-Bengal plate-agglutination test
Confirmation using competitive enzyme-linked immunosorbent assay
Data analysis
Results
Discussion
Conclusion
Chapter 3 Animal- and Herd-level Prevalence of Bovine Genital Campylobacteriosis and Trichomonosis in Cattle Herds in Northern Nigeria
Abstract
Introduction
Materials and Methods
Sampling area and sample size
Sampling for Campylobacter fetus and Tritrichomonas foetus from bulls
Sampling for Campylobacter fetus and Tritrichomonas foetus from aborted foetuses
Isolation of Campylobacter fetus and Tritrichomonas foetus
Other data collected
Data analysis
Results
Herd-level prevalence of campylobacteriosis
Animal-level prevalence of campylobacteriosis
Distribution of C. fetus venerealis, C. f. fetus and C. f. venerealis biovar intermedius strains
Association between campylobacteriosis and brucellosis
Animal- level prevalence of trichomonosis
Discussion
Conclusion
Chapter 4 Herd-level risk factors for Campylobacter fetus infection, Brucella seropositivity and withinherd seroprevalence of brucellosis in cattle in northern Nigeria
Abstract
Introduction
Materials and Methods
Study areas
Sample size and sampling strategy
Animal sampling
Serological testing for Brucella abortus
Isolation of Campylobacter fetus from bulls
Questionnaire
Statistical analysis
Results
Discussion
Conclusion
Chapter 5 Reproductive diseases, reproductive disorders and factors affecting calving rate of cattle in three states of Northern Nigeria
Abstract
Introduction
Materials and Methods
Study areas and study design
Animal and herd classification
Sample collection and testing for Brucella abortus
Sample collection and isolation of Campylobacter fetus from bulls
Additional data collection
Determination of annual calving rate
Statistical analysis
Results
Herd structure
Reproductive parameters
Reproductive status and body condition score
Reproductive status of heifers and parity of cows and heifers
Number of calves per cow lifetime in the herd and productive life of the cows
Factors associated with calving rate
Reproductive disorders and hygroma
Discussion
Conclusion
Chapter 6 General Discussion
Chapter 7 Conclusions and Recommendations
References
