Lecture 6 Flashcards
What is the rate of perinatal lamb losses influenced by
- Lamb birth weight
- Incidence of multiple births
- Genotype
- Environmental conditions
- Predation
- Age of ewe
- Nutrition
What to consider when investiagting into lamb losses
- Estimation of losses
- History
- Recent weather conditions
- Nutrition and management during pregnancy and lambing
- Trace elements supplementation
- Lambing paddock
- Breed, age sheep
- Lamb post-mortem
- Was lamb born dead or alive
- Why was it born dead or why did it die
- Provide farmer with labels
What to investiagte when doing a lamb post-mortem
- Weight, sex
- External examination
- Open lamb placed on its right side
What are the major causes of perinatal lamb losses
- Starvation, mis-mothering, exposure - major facots - multi-factorial condition
- Dystocia
- Predation
What are the minor causes of perinatal lamb losses
- Lethal congenital malformations
- Infectious diseases
- Trauma other than dystocia
- Trace element deficiencies
SME complex: explain
- Multi-factorial condition
- Small birth weight and/or part of a twin
- External examination
- Cleaned or not? Walked or not?
- Pathology
- Subcontaneous oedema of extremities
- Breathed or not
- Presence of milk clot in abomasum
- Oresence of white scattered subtance in intestinal lymphatics
- Brown fat reserves
What is seen externally with dystocia
- Meconium stains on birth coat
- Subcutaneous oedema head, distal legs
What is seen in the abdominal cavity with dystocia
Adominal bleeding from liver trauma
What is seen in the thoracal cavity with dystocia
Petechia and ecchymoses of the pleura, thymus and heart
What is seen in the brain with dystocia
Haemorrhage and congestion in and aroug the cranial and spinal meninges, persence of subdural clots
What is primary predation
Lamb appears normal but shows signs of fatal injury from predator
What is secondary predation
- Lamb is abnormal or injured at birth, starved… with signs of fatal injury of predators
What are the predators and what is seen on the animal
- Fox/wild dogs/dingo
- Check skin for teeth punctures
- Prefer heart, lungs, liver and kidney
- Crow
- Usually penetrate through anus, navel, eyes or tongue
- Wedge-tail eagle
- small punctures on skull
- Large opening through the ribcage or abdomen
- Pig
- Extensive damage to carcus
What causes congenital defects
- Atresia ani, eye abnormalities, schistosoma reflexa, spina bifida, polycystic
- Schmallenberg virus
- Akabane
- Viral outbreak transmitted by Culicoides breitarsis
- Outbreaks occur when ewes become infected whhen pregnant and have not been previously exposed
- Abortion, still birth, congenital deformities
What are infectious diseases
- Navel infection
- Fusobacterium necrophorum
- Hygine around lambing, inadequate colostrum intake
- Navel infectiosn -> multi-organ abscessation
- Weakly lambs
- Campylobacteriosis/toxoplasmosis/Hairy shaker
- Water mouth (E.coli endotoxaemia)
- Colonization of intestines by E.coli
- Hygine, colostrum intake
- CS: 1-3 day old lambs, appear depressed, reduced gastro-intestinal motility, increased abdominal tension, profuse salivation -> often die within 24 hours
- Treatment: early treatment is needed
What is the trace element deficiencies
- Selenium deficiencies
- White muscle disease in lambs
- Heart/skeletal muscle lesions
- Copper deficiency
- Swayback - enzoonotic ataxia
- Hypomyelinogenesis of CNS
- Iodine deficiency
- Goitre
- Subclinical iodine deficiency
What is iodine essential for
Thyroid hormone production
What is they thyroid hormone necessary for
CNS development and foetal growth and thermoregulation after birth
Explain subclinical iodine deficiency
- Decreased metabolic rate
- Impaired brain development, reduced lung development, impaired suckling behaviour
- Weak lambs and kids susceptible to cold stress and death
What are the signs of iodine deficiency
- Small woolless lambs which are weak and susceptible to cold stress
- Usually also high incidence of still births
- Goitre - enlarged thyroid -> may cause dystocia
- Goats more susceptible than sheep
How to diagnose iodine deficiency
- Compare thyroid weight (g) to lamb body weight (kg)
How to treat and prevent iodine deficiency
- Lugols iodine to lambs for 15 days
- Shelter for lambs
- Potassium iodine drench Iodised salt blocks
- Prevent pregnant ewes of grazing crops containing goitrogens
How to control and decrease lamb mortality
- Ewe health and nutrition
- Select appropriate lambing paddocks
- Avoid disturbing lambing ewes
- Predator control
- Cull ewes with mastitis, teat injuries
What causes lactation deaths
- Losses at this time are usually minor
