Diagnosis of Tritrichomonas foetus in bulls by culture and PCR methods

The aim of this work was to examine the effects of sampling method on accuracy of culture for Tritrichomonas foetus; and the effects of sampling method, time delay, and addition of a DNA preservative on the accuracy of a PCR test. Samples from two different sources were used for Experiment 1. Preputial scrapings were collected from one group of three infected and one uninfected bull 10 times. Secondly, samples were collected from 5 infected bulls by both sheath washing and scraping on 6 occasions, while 8 uninfected animals were sampled three or more times. Twenty nine out of 30 samples from the first sample set were found to be positive, and 83 % of samples collected by both methods for the second sample set tested positive. No samples from the control bulls were found to be positive. Scraping was found to offer significant practical advantages over washing. It may be subject to greater operator variability than sheath washing. The second experiment utilised the same samples as were used for the second data set under Experiment 1. Guanidinium thiocyanate (GuSCN) was added to half of each sample. Each sample was cultured, while all samples were subjected to DNA extraction within 6 and 30 hours and after 5 days of storage at 4 °C. PCR and agarose gel electrophoresis was performed. No samples from the control animals tested positive on PCR. The sensitivity of the PCR on samples from infected bulls ranged from 0,9 in samples extracted within 6 hours to 0,31 in samples extracted after 5 days. Sampling method had no effect with the exception of samples held for 5 days with GuSCN, where sheath washing was superior to scraping. The addition of GuSCN had no effect. Holding time reduced sensitivity at 5 days, but the effect was not significant at 30 hours. It is concluded that preputial scraping is equal in sensitivity to washing for culture of Tritrichomonas foetus. Preputial samples for PCR testing should be submitted as soon as possible after collection, and the addition of GuSCN has no effect. Samples collected by sheath washing may be superior to those collected by scraping for PCR testing. The requirement for a test with sufficient sensitivity to allow reliable identification of infected bulls based on one sample has not been met with the described method.Dissertation (MMedVet (Gyn))--University of Pretoria, 2002.Production Animal Studiesunrestricte

Comparative aspects of immunity and vaccination in human and bovine trichomoniasis : a review

Trichomonas vaginalis and Tritrichomonas foetus are important extracellular protozoans that cause, respectively, human and bovine venereal diseases. Trichomonads are extracellular parasites that primarily inhabit the genital tracts of the mammalian hosts where they overcome the mucus barrier and parasitize mucosa by contact-dependent or contact-independent cytotoxicity. Transient immunity is usually achieved by the host after clinical infection. At present, vaccination in cattle reduces infection rates and reproductive wastage in affected herds. After vaccination, immunoglobulin G (IgG) levels increase in systemic circulation while immunoglobulin A (IgA) levels rise in the vagina. Only moderate protection is conferred by means of vaccination. Future vaccine development strategies are needed for cattle to enhance the antigenic component or use adjuvant that strongly activates the innate immune response to produce safe and potent vaccines. This paper reviews the current knowledge of the immunology of trichomoniasis infection and the challenges and potential of vaccines in the control of the infection in human and bovine trichomoniasis.Institute of Food, Nutrition and Well-being (IFNuW) from the University of Pretoria, South Africa.http://link.springer.com/journal/112502017-01-30hb201

Brucellosis, genital campylobacteriosis and other factors affecting calving rate of cattle in three states of Northern Nigeria

BACKGROUND: Reproductive diseases limit the productivity of cattle worldwide and represent an important obstacle to profitable cattle enterprise. In this study, herd brucellosis and bovine genital campylobacteriosis (BGC) status, and demographic and management variables were determined and related to predicted calving rate (PrCR) of cattle herds in Adamawa, Kaduna and Kano states, Nigeria. Serum samples, preputial scrapings, questionnaire data, trans-rectal palpation and farm records were used from 271 herds. The Rose-Bengal plate test and competitive enzyme-linked immunosorbent assay were used for Brucella serology and culture and identification from preputial samples for BGC. A herd was classified as positive if one or more animals tested positive. The PrCR was determined as the number of calvings expected during the previous 6 and next 6 months as a percentage of the number of postpubertal heifers and cows in the herd. A multilevel linear regression model was used to estimate the herd-level effect of Brucella abortus seropositivity, Campylobacter fetus infection and other factors on calculated PrCR. RESULTS : The reproductive performance of the cattle herds was generally poor: Only 6.5% of the nursing cows were pregnant and 51.1% were non-pregnant and acyclic; the mean annual PrCR was 51.4%. Brucella abortus and C. fetus infection of herds were independently associated with absolute reduction in PrCR of 14.9% and 8.4%, respectively. There was also a strong negative association between within-herd Brucella seroprevalence and PrCR. Presence of small ruminants, animal introduction without quarantine and the presence of handling facilities were associated with lower PrCR, whereas larger herd size, supplementary feeding, routine mineral supplementation and care during parturition were associated with higher PrCR. CONCLUSIONS : Brucellosis and BGC may be largely responsible for the poor reproductive performance of indigenous Nigerian cattle. Farmer education and measures to improve the fertility of cattle herds are suggested.The partial funding by the Department of Production Animal Studies, University of Pretoria is appreciated.http://www.biomedcentral.com/bmcvetresam201

Interactions between negative energy balance, metabolic diseases, uterine health and immune response in transition dairy cows

The biological cycles of milk production and reproduction determine dairying profitability thus making management decisions dynamic and time-dependent. Diseases also negatively impact on net earnings of a dairy enterprise. Transition cows in particular face the challenge of negative energy balance (NEB) and/or disproportional energy metabolism (fatty liver, ketosis, subacute, acute ruminal acidosis); disturbed mineral utilization (milk fever, sub-clinical hypocalcemia); and perturbed immune function (retained placenta, metritis, mastitis). Consequently NEB and reduced dry matter intake are aggravated. The combined effects of all these challenges are reduced fertility and milk production resulting in diminishing profits. Risk factors such as NEB, inflammation and impairment of the immune response are highly cause-and-effect related. Thus, managing cows during the transition period should be geared toward reducing NEB or feeding specially formulated diets to improve immunity. Given that all cows experience a reduced feed intake and body condition, infection and inflammation of the uterus after calving, there is a need for further research on the immunology of transition dairy cows. Integrative approaches at the molecular, cellular and animal level may unravel the complex interactions between disturbed metabolism and immune function that predispose cows to periparturient diseases.Institute of Food, Nutrition and Wellbeing (IFNuW) from the University of Pretoria, South Africa.http://www.elsevier.com/locate/anireproscihb2014ab201

Curricular renewal at the southern tip of Africa : the ‘2016’ veterinary curriculum at the University of Pretoria

Four years after the institution of a new curriculum at the University of Pretoria's Faculty of Veterinary Science, a second major curricular renewal was initiated as a result of several pressing drivers, many of which were unique to the national and institutional context. During the project, South African higher education was disrupted by student protests prompted by financial pressures on students, the overt colonial structure of higher education, and the need to accelerate transformation of the sector. A structured curricular renewal process was followed, including the laying down of the principles, the structuring the macro-curriculum as a story, the design of a meso- and micro-curriculum, and the mapping of the curriculum to Day One outcomes. The resulting program is a 6-year bachelor's degree with a blend of discipline and species modules, with the first cohort graduating in 2016. There is a strong focus on skills embodied in a 62-week experiential component, managed using a unique custom-designed online platform for booking placements, documenting exposure, assessing competency, and providing feedback to students. The experiential training includes a large elective component. Several causes of loss of impetus during the process are discussed and proposals are made for avoiding these. The value of accreditation as a driver and a source of inputs is evident. The process has succeeded in producing a significantly reshaped curriculum that has been well received by external stakeholders.http://jvme.utpjournals.press/loi/jvme2018-09-06hj2017Production Animal Studie

Prevalence of bovine genital campylobacteriosis and trichomonosis of bulls in northern Nigeria

BACKGROUND: A survey was conducted to determine the prevalence of campylobacteriosis and trichomonosis, and their concurrence with brucellosis, in cattle in three states of northern Nigeria. METHODS: A total of 602 preputial samples was collected from bulls in 250 herds and tested using culture and identification. Various indigenous and exotic breeds were studied and four major management systems were encountered. Age of the cattle was estimated using dentition, farm records or cornual rings. RESULTS: The estimated true animal-level prevalence of Campylobacter fetus infection was 16.4% (95% CI: 13.0-20.7), of which 18.5% was C. f. fetus and 81.5% was C. f. venerealis. Of the latter, 92% were C. f. venerealis biovar intermedius strains. Animal-level prevalences in Adamawa, Kano and Kaduna states were 31.8%, 11.6% and 8.3% respectively, and were highest in bulls >7 years old (33.4%) and in the Gudali breed (28.8%). Of the 250 herds, 78 (25.5%, 95% CI: 19.4-32.7) had at least one infected bull, and herd prevalence was highest in the pastoral management system (43.5%). After adjustment for confounding using multivariable analysis, the odds of C. fetus infection were highest in Adamawa state (P < 0.01), in the pastoral management system (P < 0.01), and in bulls >7 years old (P = 0.01), and tended to be higher in Bos taurus breeds (P = 0.06). There was a strong positive association between the presence of campylobacteriosis and brucellosis (P < 0.01), both within bulls (OR = 8.3) and within herds (OR = 16.0). Trichomonosis was not detected in any herds. CONCLUSION: Bovine genital campylobacteriosis is prevalent particularly in the pastoral management system in northern Nigeria, with C. f. venerealis biovar intermedius as the major aetiology. There was a strong positive correlation between the occurrence of campylobacteriosis and brucellosis. No evidence of trichomonosis was found in herds in this study.The study was partially funded by the Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria.http://www.actavetscand.com/content/55/1/56am2013ab201

A large seroprevalence survey of brucellosis in cattle herds under diverse production systems in northern Nigeria

BACKGROUND: This study was carried out to investigate the status of brucellosis in cattle under various management systems in Adamawa, Kaduna and Kano states, northern Nigeria. Using multi-stage sampling, serum samples of 4,745 cattle from 271 herds were tested using the Rose-Bengal plate-agglutination test (RBPT) and positives were confirmed using a competitive enzyme-linked immunosorbent assay (c-ELISA). RESULTS: Prevalence estimates were calculated by adjusting for sampling weights and where possible for test sensitivity and specificity. Thirty-seven percent of all animals were RBPT positive, and after confirmation with c-ELISA the overall animal-level prevalence, adjusted for sampling weights, was 26.3% (95% CI, 22.1%-31.0%). Of the herds sampled, 210 (77.5%; 95% CI, 68.6%-84.5%) had at least one animal positive to both tests; this did not differ significantly between states (P = 0.538). Mean within-herd seroprevalence in positive herds was 30.2% (95% CI, 25.3%-35.1%) and ranged from 3.1% to 85.7%. Overall animal-level seroprevalences of 29.2% (95% CI, 22.5%-36.9%) n = 1,827, 23.3% (95% CI, 18.9%-28.3%) n = 1,870 and 26.7% (95% CI, 18.8%-36.7%) n = 1,048 were observed in Adamawa, Kaduna and Kano states, respectively (P = 0.496). A significantly higher seroprevalence was found in males (38.2%; 95% CI, 31.7%-45.2%) than in females (24.7%; 95% CI, 20.4%-29.5%) (P < 0.001) and in non-pregnant females (27.8%; 95% CI, 22.9%-33.5%) than in pregnant females (17.2%; 95% CI, 13.6%-21.5%) (P < 0.001). Seroprevalence increased with increasing age (P < 0.001), from 13.5% (95% CI, 8.9%-19.9%) in cattle <4 years to 35.0% (95% CI, 28.5%-42.3%) in cattle >7 years. Seroprevalence also varied between management systems (P < 0.001): pastoral systems 45.1% (95% CI, 38.6%-51.9%), zero-grazing systems 23.8% (95% CI, 6.8%-59.2%), agro-pastoral systems 22.0% (95% CI, 17.3%-27.8%), and commercial farms 15.9% (95% CI, 9.5%-25.5%). Seroprevalence did not differ significantly between breeds or lactation status. CONCLUSION: This is the first large study to assess the prevalence of bovine brucellosis over a wide geographic area of northern Nigeria, in a variety of management systems and using accurate tests. The seroprevalence of brucellosis was high, and higher than results of previous studies in northern Nigeria. The pastoral management systems of the traditional Fulanis may be encouraging the dissemination of the disease. Public enlightenment of the farmers about the disease, vaccination and appropriate national control measures are recommended.The Department of Production Animal Studies and Faculty of Veterinary Science, University of Pretoria for partly funding the project, and Abubakar Tafawa Balewa University, Bauchi, Nigeria for paying salary of the principal author during the study.http://www.biomedcentral.com/1746-6148/8/14

Ultrasonographic reproductive tract measures and pelvis measures as predictors of pregnancy failure and anestrus in restricted bred beef heifers

Previous reports have shown that reproductive tract score (RTS) can predict reproduction outcomes in seasonally bred beef heifers, although the accuracy can vary. Some ultrasonographic measures of the female reproductive tract and pelvis area have also been associated with reproductive outcome in young heifers. The objectives of this study were to determine which transrectal ultrasound or pelvis measures taken at a single examination are independent predictors of reproductive failure, and if the RTS system can be optimised with this information. In this observational study 488 year-old beef heifers in 2 birth cohorts were followed from prior to first breeding until confirmation of pregnancy. A single pre-breeding examination included BCS, RTS, ultrasound measures of the reproductive tract (length and diameter of the left and right ovaries, presence and diameter of a CL, largest follicle diameter and left uterus horn diameter) and transverse and vertical diameters of the pelvis. Additional farm records including dam parity, sire, birth weight and birth date, weaning weight, weaning date, pre-breeding BW, AI dates and semen used were available. Breeding consisted of 50 d of AI, followed 5 to 7 d later by a 42 d bull breeding period. Pregnancy failure was defined as the failure to become pregnant after the AI and bull breeding periods while anestrus was defined as the failure to be detected in estrus during the 50 d AI period. From the pre-breeding data and farm records independent predictors of pregnancy failure and anestrus were identified using step-wise reduction in multiple logistic regression models. Age at the onset of breeding was the only consistent independent predictor of pregnancy failure and anestrus in both cohorts of this study (P < 0.05). BCS, uterus horn diameter, absence of a CL, largest follicle of less than 13 mm and pelvis area (PA) were the pre-breeding examination variables that remained in prognostic models (P < 0.1). Combining either the model based on the three remaining ultrasound measures or RTS with PA provided more accurate prognostic models for pregnancy failure and anestrus than using RTS alone (P < 0.05). It is concluded that ultrasound measures have prognostic value for pregnancy failure in restricted bred yearling heifers as a result of their association with anestrus, and that smaller pelvis area has additional prognostic value for poor performing heifers.http://www.theriojournal.com2017-02-28hb201

Evaluation of pre-breeding reproductive tract scoring as a predictor of long term reproductive performance in beef heifers

In a 7-year longitudinal study 292 Bovelder beef cows in a restricted breeding system inSouth Africa were observed from 1 to 2 days before their first breeding season, when repro-ductive tract scoring (RTS, scored from 1 to 5) was performed, until weaning their 5thcalves. The objective was to determine whether pre-breeding RTS in heifers is a valid toolto predict long-term reproductive performance. Outcomes measured were failure to showoestrus during the first 24 days of the first 50-day AI season (24-day anoestrus), failureto become pregnant during each yearly artificial insemination (AI) season (reproductivefailure), number of days from the start of each AI season to calving, and number of years toreproductive failure. The effect of RTS on each outcome was adjusted for year of birth, pre-breeding age, BW and body condition score (BCS), and for 24-day anoestrus, bull, gestationlength, previous days to calving and previous cow efficiency index, the latter two in thecase of the 2nd to the 5th calving season. During their first breeding season, heifers withRTS 1 and 2 combined were more likely to be in anoestrus for the first 24 days (OR = 3.0,95% CI 1.5, 6.4, P = 0.003), and were also more likely to fail to become pregnant even afteradjusting for 24-day anoestrus (OR = 2.1, 95% CI 1.1, 3.9, P = 0.025), compared to those withRTS 4 and 5 combined. Animals with RTS 1 and 2 combined were at increased risk of earlyreproductive failure compared to those with RTS 4 and 5 combined (HR = 1.4, 95% CI 1.0,1.9, P = 0.045) although RTS was not associated with calving rate or days to calving after thesecond calving season. Low RTS at a threshold of 1 had consistent specificity of ≥94% forboth 24-day anoestrus and pregnancy failure, however its predictive value was lower inthe age cohort with a higher prevalence of anoestrus. We conclude that RTS is a valid man-agement tool for culling decisions intended to improve long-term reproductive success ina seasonal breeding system, by excluding heifers that are likely to fail to become pregnantor likely to calve late during their first calving season.This research was performed under protocol no V089/13, as approved by the Animal use and Care Committee of the University of Pretoria.http://www.elsevier.com/locate/prevetmedhb201

Bull breeding soundness evaluation in Southern Africa

The motivation for and process leading up to the publication of a new bull breeding soundness certification standard endorsed by the South African Veterinary Association is described. The veterinary certificate of bull breeding soundness and explanatory notes and minimum standards are shown. The first component of the certificate is a declaration by the veterinarian that the bull complies with the minimum standards set for examinations for the selected purpose, these being for use as a natural service sire, as a donor of semen for distribution, and for insurance purposes. This is followed by the details of the bull and owner, and a list of the recommended examinations and tests for the bull with provision for which were performed. Certificates are available in book form with the explanatory notes and minimum standards on the reverse, and a carbon copy which remains in the book. The clarity and ease of completion of the document are regarded as being positive features. Bulls are either classified as breeding sound or not, with no actual parameters indicated on the document and no certificate issued for those which do not meet the set criteria. Contact details of the parties involved are shown on the certificate to allow for communication as a means of avoiding disputes