The Occurrence of Congenital Infections Associated With Perinatal Lamb Mortality

Haughey, K. G.; Hughes, K. L.; Hartley, W. J.

doi:10.1111/j.1751-0813.1967.tb08860.x

Cited by 21 publications

(3 citation statements)

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“…5,16,17,36 It was not possible to determine the impact of the number of animals included per submission, but it has been previously reported that the likelihood of detecting an infectious agent is improved where samples from more aborting ewes are available. 8,37 Autolysis of tissues was commonly reported for samples submitted for histopathology, and this was consistent with other abortion studies. 16,17,38 Autolysis of specimens is often unavoidable and is a consequence of the disease process or maceration before expulsion from the uterus.…”

Section: Discussionsupporting

confidence: 85%

“…Inclusion of placental tissue in submissions increased the probability of making an aetiological diagnosis by 2.3 times, and this was consistent with previous studies 5,16,17,36 . It was not possible to determine the impact of the number of animals included per submission, but it has been previously reported that the likelihood of detecting an infectious agent is improved where samples from more aborting ewes are available 8,37 …”

Section: Discussionsupporting

confidence: 81%

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Ovine abortion and stillbirth investigations in Australia

Clune

Beetson

Besier³

et al. 2020

Aust Veterinary J

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Fetal loss and lamb mortality between mid‐pregnancy and weaning are important economic and welfare issues for the Australian sheep industry. The aim of this study was to determine common causes of ovine abortion and stillbirths based on submissions to veterinary laboratories and identify factors that impact the determination of an aetiological diagnosis. Data for 529 investigations on abortion or stillbirth between 2000 and 2018 were retrieved from four state veterinary laboratories in Western Australia, South Australia, Victoria and Tasmania. An aetiological diagnosis was made for 57% of investigations. Investigations that included placental tissue samples were more than twice as likely to have an aetiological diagnosis compared to investigations without placenta (P = 0.017, 95% confidence interval 1.1, 4.5). Of the investigations where an aetiological diagnosis was made, 81% involved infectious abortion, with Campylobacter spp. (32%), Listeria spp. (25%) and Toxoplasma gondii (9%) being the three most common abortigenic pathogens implicated. The remaining 19% of investigations with an aetiological diagnosis included a wide range of infectious and non‐infectious diseases. Diagnoses made varied year to year and between states. No evidence of exotic abortigenic pathogens were reported. Veterinary practitioners can improve the probability of an aetiological diagnosis by emphasising to farmers the importance of collecting any aborted material, especially placenta, and appropriate storage of the tissues until they can be submitted to the laboratory. Some diseases that cause abortion in Australian sheep have zoonotic potential, and veterinary practitioners play an important role in educating clients about appropriate hygiene when handling pregnant and lambing ewes or any aborted material.

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Section: Discussionsupporting

confidence: 85%

Section: Discussionsupporting

confidence: 81%

Ovine abortion and stillbirth investigations in Australia

Clune

Beetson

Besier³

et al. 2020

Aust Veterinary J

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“…Congenital infections associated with perinatal mortality and abortion Yersinia pseudotuberculosis70 liver, occasionally in lungs and kidneys…”

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confidence: 99%

Perinatal lamb mortality - its investigation, causes and control

Haughey¹

1991

J. S. Afr. Vet. Assoc.

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Methods of investigating perinatal loss in grazing sheep flocks are reviewed and evaluated. The "wet-dry" method is the simplest method for assessing minimal prevalence, whereas the differences between the numbers of single and twin foetuses present at ultrasonic determination of litter size during pregnancy, and the numbers of single and twin lambs present at lamb-marking, is the most precise. The veterinary investigation of field mortality involves full autopsy of a representative sample of dead lambs, a history of prenatal nutrition, disease and husbandry, as well as a qualitative estimate of weather conditions over the period of lamb collection. Pathological processes may be identified in over 95% of deaths and the specific cause determined in about 75% of deaths. The identification of the specific causes in the remainder of deaths, all classified as the starvation-mismothering-exposure (SME) complex, requires intensive, costly, on-site observation, and physiological and biochemical assessment. The probable causes of these deaths include prenatal physiological handicaps resulting from placental insufficiency, aberrant parent-offspring behaviour, management-induced mismothering, misadventure, inadequate milk supply or teat and udder abnormalities, and cold-induced starvation. The gross pathology and pathophysiology of birth stress and the SME complex, which are associated with at least 80% of mortality, are summarised. Birth injury to the foetal central nervous system, characterised by cranial and spinal meningeal haemorrhage is exclusive to parturient deaths and the SME complex. Observed flock prevalences range from 81% to 100% in parturient deaths, and 20% to 57% in the SME complex. The high total prevalence and experimental evidence, indicate the major causal role of birth stress in the pathogenesis of these entities. Lethal congenital malformations, infections (both congenital and acquired after birth), trace element deficiencies and predation are reviewed as minor causes. The new understanding of the pathogenesis of perinatal lamb mortality, recognises the heritable nature of birth mass, maternal pelvic dimensions, parent-offspring behaviour, and the resistance of neonates to cold. Control measures need to incorporate selection for maternal rearing ability, further refinement of prenatal nutritional management of twin-bearing ewes, disease control, provision of shelter for lambing flocks, and avoidance of husbandry: practices which frustrate innate parent-offspring behaviour. A selection programme is summarised.

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Spontaneous congenital developmental abnormalities observed at necropsy in a large survey of newly born dead lambs

1972

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In a systematic necropsy study of 4408 newly born dead lambs derived from 79 flocks over two lambing seasons malformation considered sufficient to impair viability was observed in 80 carcasses. Agnathia was observed in 25 carcasses and comprised the major component of congenital lethal malformations. Lambs of both sexes were affected. Its occurrence was often associated with anotia, ear displacement, or ear malformation. Factors thought to be associated with this abnormality are reviewed and attention drawn to the lack of knowledge concerning the embryonic development of the first branchial arch and related structures in sheep. Developmental defects of the muscular and skeletal systems, central nervous system, cardiovascular system (particularly ventricular septal defects), and imperforate intestinal tract were the next most common malformations.

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The Occurrence of Congenital Infections Associated With Perinatal Lamb Mortality

Cited by 21 publications

References 20 publications

Ovine abortion and stillbirth investigations in Australia

Ovine abortion and stillbirth investigations in Australia

Perinatal lamb mortality - its investigation, causes and control

Spontaneous congenital developmental abnormalities observed at necropsy in a large survey of newly born dead lambs

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