Liver and Spleen Disorders in Ruminants PDF

LIVER AND SPLEEN DISORDERS IN RUMINANTS LUISA SOARES LMV, FHEA, MRCVS LECTURER IN PRODUCTION ANIMAL MEDICINE  LEARNING OBJECTIVES By the end of this lecture should be able to Construct a differential diagnosis list based on clinical presentations associated liver and sple...

LIVER AND SPLEEN DISORDERS IN RUMINANTS LUISA SOARES LMV, FHEA, MRCVS LECTURER IN PRODUCTION ANIMAL MEDICINE  LEARNING OBJECTIVES By the end of this lecture should be able to Construct a differential diagnosis list based on clinical presentations associated liver and spleen disorders and choose appropriate diagnostics. Determine appropriate medical and surgical interventions in the management and treatment of liver and spleen disorders in large animals. Determine appropriate prognosis, based on an individual animal and a herd. Determine control measures appropriate for liver and spleen disorders in large animals 2 W H Y I S T H E L I V E R I M P O R TA N T ? Ruminant metabolism is highly dependent on gluconeogenesis Protein synthesis Storage of trace elements Conversion of ammonia to urea Liver 13 12 11 10 9 8 7 #uniofsurrey 3 W H Y I S T H E S P L E E N I M P O R TA N T ? Production of RBCs and WBCs Non-athletic species so no need for splenic contraction Chronic immunosuppressive diseases are rarely reported in cattle BVD? No specific conditions of the spleen in farm animals 4 DIAGNOSTICS Biochemistry Liver enzymes – GGT (acute), AST, LDH Albumin – synthesised in the liver Globulin – mainly immunoglobulins, which are synthesised in lymphoid tissue BUN – metabolised in the liver, excreted in the kidneys Bilirubin – excreted constantly in ruminants Serology – infectious diseases Faecal analysis – Fluke Post-Mortem Examination Ultrasound Rarely used Fatty liver – hyperechoic Abscesses Palpation and percussion can be useful for detecting abnormalities but lack specificity and need experience Biopsy for trace elements or fatty change 5 DISEASES OF RUMINANTS Liver Fluke Black’s disease Infections – abscesses and hepatitis Fatty liver Trace elements – copper, selenium, secondary photosensitisation Spleen BLV? BVD? 6  LIVER FLUKE Fasciola hepatica Minor flukes (to be aware of) Fasciolodies magna – not present in the UK Dicrocoelium dendriticum Indirect lifecycle Fasciola – snail Dicrocoelium – ant 7 L I V E R F L U K E – FA S C I O L A H E PAT I C A » Immature fluke migrate from the small Ingestion of intestine through the liver Metacercaria in grass Adult fluke live in the bile ducts and produce eggs into the gallbladder Cercaria on Eggs in faeces pasture Snail (7-10⁰C) ingests Miracidium 8 L I V E R F L U K E – FA S C I O L A H E PAT I C A Clinical signs Weight loss/poor growth Scour Sudden death Diagnosis Faecal egg count (sedimentation) Coproantigen Post-Mortem exam/abattoir reports Treatment Adult fluke – Closantel, Nitroxynil All stages – Triclabendazole Prevention Pasture rotation 9  L I V E R F L U K E – FA S C I O L A H E PAT I C A Chronic Fluke Acute Fluke Aetiopathogenesis Fluke build up slowly in the liver over the course Fluke eggs build up on the pasture over the of the grazing season grazing season. Ingested by naive lambs, mass migration through the liver Timing Disease peaks during late housing period Late grazing season (September/October) (January/February) Type of Fluke Adult Immature Age Adult ewes First season lambs Clinical signs Weight loss Sudden death Diarrhoea Ill thrift Diagnosis Faecal egg count Biochemistry – severe liver damage Fluke coproantigen Fluke coproantigen Post-mortem Treatment Closantel/Nitroxynil Triclabendazole 10 F L U K E T R E AT M E N T D E C I S I O N S Consider factors such as fluke challenge level, seasonal timing, and farm management practices. Different flukicides target various life stages of fluke. Avoid overusing the same product to prevent resistance. Resistance Management Triclabendazole is the ONLY effective flukicide against immature fluke but has shown resistance in the UK. We need to protect it! No flukicides have persistent activity; they kill existing fluke but don’t prevent reinfection. Alternatives to Triclabendazole Closantel: Effective for immature fluke in autumn (5 week-old fluke). Other Options: Nitroxynil, albendazole, oxyclozanide, and clorsulon for adult fluke (or chronic Fluke). Combination Products Combination fluke and worm products are discouraged as they may increase resistance risks. https://www.scops.org.uk/internal-parasites/liver-fluke/choosing-a-flukicide-product/ 11 FLUKE CONTROL 12 https://www.cattleparasites.org.uk/app/uploads/2023/09/liver-fluke-310823.pdf BLACK DISEASE Clostridium novyi Anaerobic spore forming rod, endemic in the environment. Needs anaerobic conditions to produce endotoxin. Acute hepatic damage, commonly associated with acute fluke. 13 BLACK DISEASE Clinical signs Sudden death Diagnosis Post-Mortem (fresh) Liver enlarged with dark necrotic areas Treatment No available treatment Many authors try penicillins but limited success Prevention Clostridial toxoid vaccination Liver fluke control 14 LIVER INFECTIONS Hepatitis/abscesses Commonly caused by opportunistic pathogens Fusobacterium necrophorum Trueperella pyogenes E. coli Route of infection Systemic – septicaemia Local – anatomy 15 LIVER INFECTIONS – ROUTE Local Remote Sub-Acute Ruminal Acidosis (SARA) Septicaemia from a primary infection: Increased concentrate feeding, pH4.0) in early lactation 18 Image courtesy of Phil Scott, NADIS FAT T Y L I V E R Signalment Fat cows in early lactation Excessive fat mobilisation due to decreased feed intake and negative energy balance Clinical signs Dull, depressed Rapid weight loss Milk drop Clinical ketosis – nervous signs Inappetence Diagnosis Liver biopsy – TAG concentration Ketone measurement (cow side BHB) NEFAs in plasma (Lab) BCS assessment 19 FAT T Y L I V E R Treatment Oral propylene glycol 300ml once daily for 3-5days Ancillary therapy (weak evidence): Corticosteroids, vitamin B12, dextrose/glucose Prevention Optimise BCS in late lactation and early dry period Minimise BCS change in the late dry period (28d prior to calving) Aim to calve at 3.0 Maximise DMI in dry period Metabolic profiles 20 LIVER STORAGE DISEASE COPPER SELENIUM P H O T O S E N S I T I S AT I O N 21  COPPER TOXICITY - CLINICAL Cattle tolerate relatively high levels of copper, sheep have a lower tolerance Sheep fed cattle feed CuSO4 footbaths Low molybdenum diets (helps renal excretion) Clinical signs Sudden death Diagnosis Post-mortem – gunmetal black kidneys Renal sample for copper testing Copper is released from the liver so liver levels are often low Treatment Remove source of copper Increase molybdenum feeding 22 Image courtesy of Phil Scott, NADIS COPPER TOXICITY - SUBCLINICAL Most dairy cows are over-supplemented with copper Subclinical copper toxicity has been reported Subclinical signs Impaired fertility Milk drop Liver biopsy for copper Serum copper is relatively unaffected until liver reserves are used up https://surrey.primo.exlibrisgroup.com/permalink/44SUR_INST/1tc3s1n/cd i_webofscience_primary_000304108400025CitationCount 23 COPPER DEFICIENCY Copper deficiency is less common. In ewes it is associated with swayback in lambs. Diagnosis by low serum copper – only occurs when liver reserves are used up. Treatment – supplementary copper feeding. In NADIS 24 SELENIUM Trace element that is stored in the liver Aetiology Deficiency – soil deficiency Toxicity – accidental over-supplementation in the ration or injectable (rare) Deficiency is more common than toxicity. Clinical signs White muscle disease – skeletal and cardiac forms Diagnosis Liver or serum selenium Post-mortem Treatment Injectable selenium Prevention Mineral licks. 25  S EC O N DA RY P H OTO S E N S I T I S AT I O N » Chlorophyll is metabolised to phylloerythrin which is normally metabolised and excreted by the liver » Major liver dysfunction causes accumulation of phylloerythrins in blood and body tissues » Diagnosis Biochemical evidence of liver damage Difficult to rule out primary photosensitisation Ingestion of photodynamic plant e.g. St John’s Wort » Treatment Remove from sunlight Corticosteroids Treat underlying liver disease Euthanasia 26 Image courtesy of Phil Scott, NADIS SPLENIC DISORDERS OF RUMINANTS Bovine Leukosis Virus (BLV) – enzootic bovine leukosis Notifiable disease in the UK, endemic in the USA Causes lymphosarcomas on many organs Bovine Viral Diarrhoea Virus (BVDV) Causes immunosuppression Foetal spleen is the best organ to sample for abortion diagnostics 27