ORCID Profile
0000-0002-7374-9720
Current Organisation
Murdoch University
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Veterinary Sciences | Veterinary Medicine | Veterinary Diagnosis and Diagnostics | Veterinary Epidemiology
Horses | Expanding Knowledge in the Agricultural and Veterinary Sciences | Livestock Raising not elsewhere classified |
Publisher: MDPI AG
Date: 11-07-2022
Abstract: Mycoplasma bovis (M. bovis) can cause a multitude of diseases in cattle, with detrimental effects on the farm economy and the welfare of both adult and young cattle. The objective of this study was to determine the prevalence of M. bovis in adult cows and calves in the south-west region of Western Australia. A cross-sectional study was conducted on 29 dairy farms with 699 apparently healthy adult lactating cows and 495 young calves during 2019–2020. Nasal swabs and blood s les collected from the animals and bulk tank milk (BTM) s les were assessed for M. bovis-specific proteins and antibodies by using polymerase chain reaction (PCR) and Mycoplasma immunogenic lipase A- Enzyme-Linked Immune Sorbent Assay (MilA ELISA). A seroprevalence of 42.5% (95% CI: 38.9–46.2) and 61% (95% CI: 56.6–65.2) was found in adult lactating cows and calves, respectively. The herd-level seroprevalence of M. bovis ranged from 4% (95% CI: 07–19.5) to 92% (95% CI: 75.0–97.8) in adult lactating cows and 25% (95% CI: 10.2–49.5) to 87% (95% CI: 67.9–95.5) for calves in these farms. None of the BTM and nasal swab s les were positive for M. bovis, indicating an absence of any current active infections on the farms. The female calves and pure Holstein–Friesian animals are twice as likely to be seropositive for M. bovis compared to male calves (OR 2.4 95% CI: 1.7–3.5) and Holstein–Friesian crossbred calves (OR 2.4 95% CI: 1.7–3.5). The high seroprevalence in both adult and young cattle in the southwest dairy farms of Western Australia warrants more effective farm biosecurity measures and further evaluation of the current prevention and management measures practiced on the farms.
Publisher: University of Toronto Press Inc. (UTPress)
Date: 09-2017
Abstract: 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.
Publisher: Elsevier BV
Date: 12-2008
DOI: 10.1016/J.THERIOGENOLOGY.2008.06.098
Abstract: We estimated the effect of estrus synchronization on reproduction, production and economic outcomes in 272 beef heifers randomly allocated to a synchronized Test group or an unsynchronized Control group. The Test group received AI upon estrus detection for 6 days followed by PGF2 treatment of heifers that had not shown estrus by day 6 (PGF/6). In both groups AI was continued for 50 days, followed by a 42-day bull breeding period. Heifers were followed through their second breeding season and until they had weaned their first calves. Synchronization resulted in a reduction in median days to first insemination (8 vs. 11 in the Test and Control groups, respectively, P<0.01) and median days to calving of calves born to AI (14 vs. 20, P=0.04). There was no significant difference in pregnancy rate to the AI period (60.0% vs. 51.8%, P=0.18), final pregnancy rate (82.2% vs. 83.2%, P=0.87) or pregnancy rate to the subsequent breeding season (96.0% vs. 95.0%, P=1.00). Although mean calf weaning mass was not significantly different (207.0 kg vs. 201.4 kg, P=0.32), the total mass of calves weaned in this study was 14,843 kg vs. 13,060 kg and the benefit: cost ratio for synchronization was 2.8. It was therefore concluded that a PGF/6 protocol may affect the total mass of calves weaned by changing days to calving, weaning rate, the ratio of male: female calves born and/or the birth mass of calves.
Publisher: Elsevier BV
Date: 08-1997
DOI: 10.1016/S0093-691X(97)00246-X
Abstract: A healthy, 5-yr-old rough collie bitch exhibited prolonged gestation, characterized by intrauterine fetal death and plasma progesterone concentrations (PPC) above 6 nmol/L/d until Day 65 or 66 of cytologic diestrus, which then only dropped following treatment with dinoprost tromethamine. The bitch showed no signs of parturition prior to laparotomy and hysterotomy on Day 63, which revealed 5 corpora lutea (CL) on the left ovary and 1 on the right ovary 5 full-term, dead conceptuses without obvious autolysis but with 4 of the 5 placentas detached and a tightly closed cervix. All conceptuses were in the left uterine horn. Treatment with dinoprost tromethamine was initiated 1 d after hysterotomy and was continued for IO d (120 microg/kg twice daily for a total dose of 240 microg kg/d). The discharge of lochia through the cervix and lactation started 3 d after the onset of treatment. Plasma progesterone concentration was 14.4, 16.2 and 1.6 nmol/L/d on the day of hysterotomy and at 1 and 3 d after the onset of prostaglandin therapy, respectively. The reason for the failure of luteolysis to occur is not known.
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.PREVETMED.2013.05.016
Abstract: Brucellosis and c ylobacteriosis are economically important diseases affecting bovine reproductive efficiency in Nigeria. A questionnaire-based survey was conducted in 271 cattle herds in Adamawa, Kaduna and Kano states of northern Nigeria using multistage cluster s ling. Serum from 4745 mature animals was tested for Brucella antibodies using the Rose-Bengal plate test and positives were confirmed in series-testing protocol using competitive enzyme-linked immunosorbent assay. Preputial scrapings from 602 bulls were tested using culture and identification for C ylobacter fetus. For each disease, a herd was classified as positive if one or more animals tested positive. For each herd, information on potential managemental and environmental risk factors was collected through a questionnaire administered during an interview with the manager, owner or herdsman. Multiple logistic regression models were used to model the odds of herd infection for each disease. A zero-inflated Poisson model was used to model the count of Brucella-positive animals within herds, with the number tested as an exposure variable. The presence of small ruminants (sheep and/or goats) on the same farm, and buying-in of >3 new animals in the previous year or failure to practice quarantine were associated with increased odds of herd-level c ylobacteriosis and brucellosis, as well as increased within-herd counts of Brucella-positive animals. In addition, high rainfall, initial acquisition of animals from markets, practice of gynaecological examination and failure to practice herd prophylactic measures were positively associated with the odds of C. fetus infection in the herd. Herd size of >15, pastoral management system and presence of handling facility on the farm were associated with increased odds, and gynaecological examination with reduced odds of herd-level Brucella seropositivity. Furthermore, the zero-inflated Poisson model showed that borrowing or sharing of bulls was associated with higher counts, and provision of mineral supplement with lower counts of Brucella-positive cattle within herds. Identification of risk factors for bovine c ylobacteriosis and brucellosis can help to identify appropriate control measures, and the use of zero-inflated count model can provide more specific information on these risk factors.
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.PREVETMED.2017.07.004
Abstract: Accurate diagnosis of pregnancy is an essential component of an effective reproductive management plan for dairy cattle. Indirect methods of pregnancy detection can be performed soon after breeding and offer an advantage over traditional direct methods in not requiring an experienced veterinarian and having potential for automation. The objective of this study was to estimate the sensitivity and specificity of pregnancy-associated glycoprotein (PAG) detection ELISA and transrectal ultrasound (TRUS) in dairy cows of South Africa using a Bayesian latent class approach. Commercial dairy cattle from the five important dairy regions in South Africa were enrolled in a short-term prospective cohort study. Cattle were examined at 28-35days after artificial insemination (AI) and then followed up 14days later. At both s ling times, TRUS was performed to detect pregnancy and commercially available PAG detection ELISAs were performed on collected serum and milk. A total of 1236 cows were s led and 1006 had complete test information for use in the Bayesian latent class model. The estimated sensitivity (95% probability interval) and specificity for PAG detection serum ELISA were 99.4% (98.5, 99.9) and 97.4% (94.7, 99.2), respectively. The estimated sensitivity and specificity for PAG detection milk ELISA were 99.2% (98.2, 99.8) and 93.4% (89.7, 96.1), respectively. Sensitivity of veterinarian performed TRUS at 28-35days post-AI varied between 77.8% and 90.5% and specificity varied between 94.7% and 99.8%. In summary, indirect detection of pregnancy using PAG ELISA is an accurate method for use in dairy cattle. The method is descriptively more sensitive than veterinarian-performed TRUS and therefore could be an economically viable addition to a reproductive management plan.
Publisher: Springer Science and Business Media LLC
Date: 09-08-2013
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.ANIREPROSCI.2013.11.007
Abstract: 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.
Publisher: Wiley
Date: 25-01-2022
DOI: 10.1111/AVJ.13149
Abstract: Bovine trichomoniasis, caused by the protozoal parasite Tritrichomonas foetus , is a highly contagious venereal disease characterised by early pregnancy loss, abortion and pyometra. Persistently infected bulls and cows are the primary reservoirs of infection in infected herds. This research investigated the prevalence of T. foetus infection in bulls from properties located across northern Australia and New South Wales. Preputial s les were collected from 606 bulls at slaughter and tested for T. foetus using the VetMAX‐Gold Trich Detection Kit (Thermo Fisher Scientific). The apparent prevalence of T. foetus infection varied between regions, with northern regions in the Northern Territory, Queensland and Western Australia showing a prevalence of 15.4%, 13.8% and 11.4%, respectively. There was some evidence of an association between infection and postcode (P = 0.06) and increasing bull age (P = 0.054). This study confirms that T. foetus infection is likely to be present in many beef breeding herds and contributing to lower than expected reproductive performance, particularly across northern Australia.
Publisher: Elsevier BV
Date: 03-2008
DOI: 10.1016/J.THERIOGENOLOGY.2007.11.007
Abstract: This study reports on the development of a data capture sheet for recording the sperm morphology of bulls. The arrangement of the data capture sheet permits the simultaneous recording of the viability and morphology of spermatozoa, and the recording of multiple defects in spermatozoa. Apart from deriving the prevalence of each type of defect, the sheet permits the derivation of the percentages spermatozoa with nuclear defects, defects of the acrosome or tail, respectively, as well as the percentages morphologically normal and normal viable spermatozoa. The arrangement of the data capture sheet further permits the rapid and easy interpretation of the sperm morphology regarding the stage of development, site and extent of malfunction of the reproductive organs, the prognosis for change in the sperm morphology over time and the extent to which defects may be compensated for by normal spermatozoa and the likely fertility of the particular semen s le. The data capture sheet permits a multidimensional, holistic interpretation of the sperm morphology of a bovine semen s le.
Publisher: Oxford University Press (OUP)
Date: 06-2009
Abstract: In this study, 272 beef heifers were studied from just before their first breeding season (October 15, 2003), through their second breeding season, and until just after they had weaned their first calves in March, 2005. This study was performed concurrently with another study testing the economic effects of an estrous synchronization protocol using PG. Reproductive tract scoring (RTS) by rectal palpation was performed on the group of heifers 1 d before the onset of their first breeding season. The effect of RTS on several fertility and production outcomes was tested, and the association of RTS with the outcomes was compared with that of other input variables such as BW, age, BCS, and Kleiber ratio using multiple or univariable linear, logistic, or Cox regression. Area under the curve for receiver operating characteristic analysis was used to compare the ability of different input variables to predict pregnancy outcome. After adjustment for BW and age, RTS was positively associated with pregnancy rate to the 50-d AI season (P < 0.01), calf weaning weight (r = 0.22, P < 0.01), and pregnancy rate to the subsequent breeding season (P < 0.01), and negatively associated with days to calving (r = 0.28, P < 0.01). Reproductive tract scoring was a better predictor of fertility than was Kleiber ratio and similar in its prediction of calf weaning weight. It was concluded from this study that RTS is a predictor of heifer fertility, compares well with other traits used as a predictor of production outcomes, and is likely to be a good predictor of lifetime production of the cow.
Publisher: Elsevier BV
Date: 03-2002
DOI: 10.1016/S0093-691X(02)00632-5
Abstract: The objectives of this study were to demonstrate the ability to cannulate the crurae of the bull's penis under ultrasound guidance, to demonstrate contrast medium injected by this route in the distal penis, and to confirm the technique to be safe and repeatable. Five adult bulls with normal serving ability were used, one being subjected to the procedure twice. The procedure was performed with the bulls under general anesthesia and in lateral recumbency. A spinal needle was passed through the skin and into the crus penis under ultrasound guidance and two syringes containing an iodine-based contrast medium were connected to it. Stimulation using an electro-ejaculator with a rectal probe was initiated, and when the penis started developing an erection, 50-100 ml of contrast medium was injected. Lateral and ventro-dorsal radiographs were taken of the extended penis during, and at intervals after, injection. After a rest period of 5 min, clearance of the contrast medium was confinned and the procedure was repeated on the other crus penis. Each case therefore, contained two attempts. Successful cannulation of the crus penis was confirmed by observing indentation of its fibrous wall by the needle, free flow of blood, lack of resistance to the injection of air, which could be seen in the crus, and fluctuation of resistance to injection in synchrony with the pulsation of the electroejaculator. Contrast medium was demonstrated in the mid or distal portion of the penis in all six cases, or on 9 of the 12 attempts. Attainment of penile erection, a larger volume of contrast medium, and the order of cannulation all enhanced flow of contrast medium to the distal portion of the penis, with the first crus giving better results. On one occasion the needle worked out of the crus penis during stimulation, resulting in injection of contrast medium into the corpus spongiosum penis. All bulls recovered uneventfully and returned to normal serving ability. It is concluded that ultrasound-guided cannulation of the crus penis is a safe and successful method for the injection of contrast medium for contrast studies of the penis, and is less invasive than the surgical method.
Publisher: MDPI AG
Date: 26-09-2017
DOI: 10.3390/ANI7100074
Publisher: Medpharm Publications
Date: 06-07-2002
Abstract: Two trials were carried out to assess the diagnostic sensitivity and practicability of preputial scraping as a method of collecting preputial material from bulls infected with Tritrichomonas foetus. In the 1st trial, preputial material was collected by simultaneous scraping and aspiration from 3 infected and 1 uninfected bull 10 times over a 5-week period. In the 2nd trial, s les from 5 infected bulls were collected by both sheath washing and scraping on 6 occasions, while 8 uninfected animals were s led 3 times. S les were cultured using a modified Trichomonas culture medium (Oxoid). In the first trial, 29 of 30 s les from infected bulls were found to be positive. In the second trial, 83 % of s les collected by both methods tested positive. In neither trial were any s les from the control bulls found to be positive. Scraping was found to be quick and safe, and offered advantages over preputial washing in that urine contamination was easily avoided, s les were smaller and more concentrated and contamination was reduced. It may, however, be subject to greater operator variability than sheath washing. It is concluded that preputial scraping is as effective as washing and represents a suitable alternative for the collection of material for direct examination and culture of Tritrichomonas foetus.
Publisher: Elsevier BV
Date: 10-2003
DOI: 10.1016/S0093-691X(03)00138-9
Abstract: The objectives of this study were to determine the detection limit of a PCR test for Tritrichomonas foetus, to investigate the effect of s ling method, guanidinium thiocyanate (GuSCN), and s le storage, and to confirm the accuracy of the test on field s les. Serial 10-fold dilutions of culture material were used to determine the detection limit. For the s le handling trial, five positive bulls were s led by sheath washing and scraping on six occasions over a period of 18 days (n=29 s les) and eight control bulls were s led three, four or six times (n=28 s les). S les were cultured, while portions with and without GuSCN were subjected to DNA extraction within 6h, after 30 h and after 5 days at 4 degrees C. PCR and agarose gel electrophoresis was performed. A two-tailed chi-square test was used to test for differences between treatments. The PCR assay showed a specificity of 98%. Its sensitivity declined with storage time, from 90% at 6h to 31% at 5 days. S ling method and GuSCN had no effect on test sensitivity. The detection limit of the assay was 100 organisms. Parallel testing of 193 field s les gave complete agreement between culture and PCR results.
Publisher: Elsevier BV
Date: 03-2007
DOI: 10.1016/J.VACCINE.2006.12.010
Abstract: Twelve serologically negative bulls were used, six were vaccinated with a modified live LSD vaccine and six unvaccinated. All were then experimentally infected with a virulent field strain of LSDV. No clinical abnormality was detected following vaccination, and mild clinical signs were seen in four vaccinated bulls following challenge. Virus was not found in semen of vaccinated bulls. Two of the unvaccinated bulls developed severe LSD and four showed mild symptoms, all excreted the virus in the semen following challenge. This study confirmed the ability of LSD vaccination to prevent the excretion of LSDV in semen of vaccinated bulls.
Publisher: Wiley
Date: 24-06-2021
DOI: 10.1111/AVJ.13096
Abstract: Identifying and quantifying the relative frequency of involuntary losses is an essential first step in developing fit‐for‐purpose herd health programmes. The objective of this study was to provide an estimate of the relative frequency of reasons for mortality among south‐west Western Australian beef and dairy cattle, based on necropsy findings from a university‐based veterinary pathology referral centre over 38 years. A total of 904 cattle were submitted for postmortem examination throughout the study period. Gastrointestinal, cardiopulmonary and reproductive conditions were the most common causes of mortality in cattle submitted for necropsy at Murdoch University for the period 1981–2018. In dairy cattle, the common problems were gastrointestinal (bloat, abomasal displacements) 18% (59/320), cardiovascular (traumatic reticulo‐pericarditis) 9% (30/320) and respiratory conditions (pneumonia) 8% (27/320). In beef cattle, the most common conditions were gastrointestinal (bloat, rumen acidosis) 11% (39/358), reproductive (metritis) 11% (38/358), cardiovascular (traumatic reticulo‐pericarditis) 7% (25/358), respiratory (pneumonia) 7% (24/358), lameness (fractures) 6%, (21/358) and hepatobiliary conditions (blue‐green algae poisoning, hepatotoxicity) 6% (21/358). Selection bias and missing data were potential confounders in this study. Although necropsy investigations provide useful information on animal mortalities and avenues for future herd health programmes, there is a need to standardise data capture methods and disease definition criteria, and conduct more detailed recording of data both at the farm level and at necropsy diagnostic centres.
Publisher: MDPI AG
Date: 15-03-2023
DOI: 10.3390/ANI13061066
Abstract: The prevention of pregnancy is desirable for female cattle destined for sale in the northern Australian rangelands for both economic and welfare reasons. Controlled access to bulls is often not feasible, nor are any non-surgical methods currently available. Many females are therefore surgically spayed. This study describes a technique for uterine tube resection (UTR), which leaves the ovaries intact and is performed using a vaginal approach, and compares the outcomes from 70 Brahman cows subjected to the procedure with 60 heifers spayed using the dropped ovary technique. The animals were monitored for 10 days following the surgery. There were no mortalities, and two animals were treated for illnesses after the UTRs and recovered. The animals subjected to both surgical procedures showed signs of pelvic discomfort and mild inflammation during recovery. The cows gained an average of 9.3 kg (SD 14.5 kg) of weight over the 10 days of the study compared to the spayed heifers, which lost 3.5 kg (SD 13.3 kg), with 19 and 63% of the animals in each of the groups losing weight, respectively. Uterine tube resection can be considered as a viable alternative to surgical spaying.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.THERIOGENOLOGY.2015.09.031
Abstract: 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 whether the RTS system can be optimized with this information. In this observational study, year-old beef heifers (n = 488) in 2 birth cohorts were followed from just before the first breeding until confirmation of pregnancy. A single pre-breeding examination included body condition score, 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, prebreeding body weight, AI dates, and semen used were available. Breeding consisted of 50 days of AI, followed 5 to 7 days later by a 42-day 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-day AI period. From the prebreeding data and farm records, independent predictors of pregnancy failure and anestrus were identified using stepwise 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). Body condition score, uterus horn diameter, absence of a CL, largest follicle of less than 13 mm, and pelvis area (PA) were the prebreeding examination variables that remained in prognostic models (P < 0.1). Combining either the model based on the 3 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 PA has additional prognostic value for poorly performing heifers.
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.PREVETMED.2014.10.016
Abstract: In a 7-year longitudinal study 292 Bovelder beef cows in a restricted breeding system in South Africa were observed from 1 to 2 days before their first breeding season, when reproductive tract scoring (RTS, scored from 1 to 5) was performed, until weaning their 5th calves. The objective was to determine whether pre-breeding RTS in heifers is a valid tool to predict long-term reproductive performance. Outcomes measured were failure to show oestrus during the first 24 days of the first 50-day AI season (24-day anoestrus), failure to become pregnant during each yearly artificial insemination (AI) season (reproductive failure), number of days from the start of each AI season to calving, and number of years to reproductive 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, gestation length, previous days to calving and previous cow efficiency index, the latter two in the case of the 2nd to the 5th calving season. During their first breeding season, heifers with RTS 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 after adjusting for 24-day anoestrus (OR=2.1, 95% CI 1.1, 3.9, P=0.025), compared to those with RTS 4 and 5 combined. Animals with RTS 1 and 2 combined were at increased risk of early reproductive 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 the second calving season. Low RTS at a threshold of 1 had consistent specificity of ≥94% for both 24-day anoestrus and pregnancy failure, however its predictive value was lower in the age cohort with a higher prevalence of anoestrus. We conclude that RTS is a valid management tool for culling decisions intended to improve long-term reproductive success in a seasonal breeding system, by excluding heifers that are likely to fail to become pregnant or likely to calve late during their first calving season.
Publisher: Springer Science and Business Media LLC
Date: 2015
Publisher: Wiley
Date: 04-2010
DOI: 10.1111/J.1439-0531.2008.01274.X
Abstract: The objectives of this work were to determine the site of persistence of lumpy skin disease virus (LSDV) in bulls shedding the virus in semen for a period longer than 28 days, to determine if the virus is present in all fractions of semen and to study lesions that developed in the genital tract. Six serologically negative postpubertal bulls were experimentally infected with a virulent field isolate of LSDV. The polymerase chain reaction (PCR) was performed on sheath washes, vesicular fluid, supernatant and cell-rich fractions of semen from day 10 to day 26 postinfection (p.i.). Bulls that were positive by PCR on the whole semen s le collected on day 28 p.i. were slaughtered and tissue s les from their genital tracts submitted for histopathological evaluation, immunoperoxidase staining, virus isolation and PCR. Two of the bulls developed severe lumpy skin disease (LSD) and were found to be shedding viral DNA in their semen on day 28 p.i. Viral DNA was identified in all semen fractions from all bulls, but mostly from the cell-rich fraction and from the severely affected bulls. The PCR assay was positive on postmortem s les of testes and epididymides from the two severely affected bulls. Virus could be recovered from the testes of these two bulls and from the epididymis of one of them. Immunoperoxidase staining was positive for LSDV staining in sections of testes and epididymides exhibiting necrosis. This study suggests that the testis and epididymis are sites of persistence of LSDV in bulls shedding virus in semen for prolonged periods and revealed that viral DNA is present in all fractions of the ejaculate.
Publisher: Elsevier BV
Date: 12-2002
DOI: 10.1016/S0093-691X(02)01081-6
Abstract: A 5-year-old cheetah suffered a complete prolapse of the left uterine horn after the birth of her second litter. Two attempts to reduce the prolapse transvaginally failed. The animal was hospitalized 13 days after the prolapse first occurred, and an ovariohysterectomy was performed to resolve the prolapse. The prolapsed uterine horn had been mutilated: its tip, together with the ipsilateral ovary was absent. Laparotomy revealed no sign of recent or past hemorrhage or adhesions, or any signs of the left ovarian artery or left ovarian vein in the remnants of the left mesovarium. A large vein crossed the uterine body from the left uterine horn to join the right uterine vein, presumably serving as the only route of venous drainage for the prolapsed uterine horn. A possible cause for the prolapse is excessive mobility of the uterus due to prior rupture of its mesial support. The animal died 24 days after surgery due to chronic renal failure, as a result of severe renal amyloidosis.
Publisher: Springer Science and Business Media LLC
Date: 2012
Publisher: Wiley
Date: 12-2020
DOI: 10.1111/AVJ.12900
Abstract: The sheath and prepuce are anatomically simple yet vital parts of the mating apparatus of the bull. They are also susceptible to a range of insults, and pathology of these structures is a common cause of infertility in both Bos taurus and Bos indicus bulls. Significant in idual and breed-based variation occurs in the looseness of the skin, the presence and development of preputial muscles, the relative position of the opening to the cranial preputial muscles, the length of the prepuce, and the prominence of the umbilicus. In idual and breed-based susceptibility to different conditions is associated with these anatomical variations. Regardless of the cause, pathology of the prepuce generally results in sepsis, prolapse, stenosis or adhesions or a combination. Clinical examination should be aimed at determining the extent of these processes and the amount of healthy prepuce which would remain following successful treatment. The inclusion of evaluation of sheath conformation in the form of a sheath score is recommended. Current scoring systems do not reflect the ersity of predisposing factors to morbidity and may therefore fail to accurately reflect the risk of morbidity. A more detailed scoring system has been proposed. Further refinement of this system is outlined, consisting of a composite of scores for depth, umbilical skin fold, prepuce eversion, and distance from cranial muscle to opening (the 'Y' factor). Validation against actual bull performance is indicated to develop a valid and useful risk-management tool for use in evaluating sheath conformation.
Publisher: Medpharm Publications
Date: 12-07-1999
Abstract: A 7-year-old Brahman cow was diagnosed as suffering from chronic foetal mummification of unknown aetiology, concurrent cystic ovarian disease, prolapse of the 2nd cervical ring and chronic cervicitis. Repeated treatment with prostaglandin F2a and oestrogen failed to resolve the mummification. A hysterotomy was performed via an incision in the dorsolateral vaginal wall. Good exposure of the uterine horn was achieved and mild post-operative complications were observed. Colpotomy can be regarded as an alternative surgical approach to the moderately enlarged bovine uterus.
Publisher: MDPI AG
Date: 10-08-2019
DOI: 10.3390/ANI9080544
Abstract: This study aimed to explore the beliefs and attitudes of a group of senior veterinary students regarding One Health and to evaluate their levels of confidence in advising the general public on preventative health issues at the human–animal interface. An online survey was communicated to senior veterinary students who were in their last two years of study. The questionnaire covered beliefs and attitudes, issues concerning the animal–human interface and participants’ confidence in diagnosing zoonoses. In total, 175 students from five Australian veterinary schools/colleges completed the online survey. The majority (96%) of students considered it their duty to promote the One Health approach, but only 36% believed there were sufficient practical frameworks for Australian veterinarian graduates to promote One Health. Interestingly, 81% (142/175) of respondents believed that veterinarians were more knowledgeable than physicians in managing zoonotic cases. Of the final-year students (n = 77), only 39% and 36% were confident in their ability to diagnose zoonoses in common companion animals and production animals, respectively. However, the number of those confident to diagnose zoonoses transmitted from wildlife was notably lower (22% (17/77)). Next-generation Australian veterinarians are keen to embrace their role in interprofessional collaboration however, training efforts are required to reassure future veterinarians on aspects of zoonoses and One Health.
Publisher: Springer Science and Business Media LLC
Date: 30-09-2016
DOI: 10.1007/S11250-015-0909-1
Abstract: 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.
Publisher: Informa UK Limited
Date: 07-03-2022
DOI: 10.1080/00480169.2022.2042413
Abstract: To gather data on the calf management and rearing practices of a subset of dairy farmers in the south-west region of Western Australia. A 30-minute face-to-face survey was conducted with dairy cattle producers in the south-west region of Western Australia from April-June 2019 to determine pre-weaning calf rearing practices. Participation was voluntary, using a self-selected subset of dairy farmers registered with a regional extension group. The questionnaire assessed three broad categories: farm demographics, colostrum harvesting and management and calf rearing practices. The study response rate was 34/140 (24%). The following key areas were identified where there were deviations from recognised best practice: Precalving: no transition diet was fed pre-calving on 4/34 (12%) of farms, and on a further 5/34 (15%) it was fed for less than 3 weeks mixing of heifers and adult cows in the calving paddocks occurred in 24/34 (70%) of the farms, with 15% (5/34) of the farms using calving induction. During calving 14/34 (41%) of the farms did not disinfect navels of new-born calves although 23/34 farmers stated that they collected calves within 6 hours of birth, data on frequency of calf pick-up (2/34 did not separate calves and dams and 19/34 picked up only once per day) indicated that on 21/34 farms (62%) the reality was that calves were picked up >12 hours after birth. Colostrum quality was not assessed appropriately on 18/34 (53%) farms and farmers overestimated how soon after birth it was administered: 23/34 (68%) reported feeding it within 6 hours of calving, despite 62% picking up calves >12 hours after calving. Regarding calf rearing practices, no pain relief before or after dehorning was used on 20/34 (59%) farms, calf bedding was removed infrequently (<weekly) on 26/35 (76%) farms and appropriate isolation of sick calves was only reported by 14/34 (41%) farmers. Although limited by the low response rate, this is the first survey of dairy calf rearing practices in the south-western region of Western Australia. We found evidence of at least one process inconsistent with industry best-practice on 34/140 (24%) of responding farms and all farms had more than one sub-optimal calf rearing practice. This highlights the need to improve calf rearing in this region and identifies key areas of deficiency for further study and extension to producers.
Publisher: Elsevier BV
Date: 03-2005
DOI: 10.1016/J.THERIOGENOLOGY.2004.06.013
Abstract: This work was done to establish the incidence and duration of excretion of lumpy skin disease virus (LSDV) in semen of experimentally infected susceptible bulls. Six serologically negative bulls 11-20 months of age were experimentally infected with a virulent field isolate (strain V248/93) of LSDV. Animals were observed for the development of clinical signs, blood was collected until day 90 after infection, and semen was collected every second day until day 18, then twice a week till day 63 and twice a month until three consecutive s les were negative when tested for LSDV by polymerase chain reaction (PCR). An aliquot of each s le which tested positive using PCR was inoculated onto cell monolayers for the recovery of virus. Two bulls developed severe lumpy skin disease (LSD), two bulls showed mild signs and two bulls showed a transient fever only. Multiple s les were positive on PCR from both of the severely affected bulls and one of the mildly affected bulls between days 10 and 159, days 8 and 132, and days 10 and 21 respectively. Only one s le from each of the other three bulls was positive on PCR. Virus was only isolated from two s les from one of the severely affected bulls and from five semen s les from the other. This study confirmed the excretion of LSDV in bovine semen for prolonged periods, even when obvious clinical signs of the disease were no longer apparent.
Publisher: Elsevier BV
Date: 10-2007
DOI: 10.1016/J.THERIOGENOLOGY.2007.06.013
Abstract: 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.
Start Date: 06-2016
End Date: 12-2019
Amount: $230,000.00
Funder: Australian Research Council
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