Health risks for lambs in autumn: Are you prepared?
As nights get longer and the weather cools, sheep farmers across Ireland face "critical management decisions", according to the Department of Agriculture, Food and the Marine (DAFM).
At this time of year, farmers will be weaning and moving lambs onto lush aftermath grazing or into housing for intensive meal feeding
According to DAFM: “These changes, while necessary for maintaining growth rates, can present significant animal health risks.
“Some common causes of sudden death in lambs during this high-risk period are systemic pasteurellosis, pulpy kidney disease, ruminal acidosis and parasitic gastroenteritis.”
Systemic pasteurellosis - a 'frequent diagnosis'
Systemic pasteurellosis is a frequent diagnosis in regional veterinary laboratories (RVLs) between September and December.
DAFM said: “The bacteria typically reside harmlessly in the tonsils of healthy sheep.
“However, periods of stress - such as weaning, transport, handling, inclement weather, heavy worm burdens or sudden movement to lush grazing or rapid dietary change - can trigger the bacteria to multiply rapidly and enter the bloodstream, leading to severe septicaemia and sudden death.
"Affected lambs are often found dead without prior clinical signs."
According to DAFM, prevention relies heavily on a “robust vaccination protocol using multivalent vaccines".
Farmers must also ensure lambs receive their primary courses and timely boosters according to manufacturer guidelines.
“Minimising handling stress, controlling gastrointestinal nematodes and managing dietary shifts gradually are equally essential," DAFM said.
'Grain overload'
Ruminal acidosis, or "grain overload," occurs when lambs ingest excessive amounts of rapidly fermentable carbohydrates, such as intensive cereal concentrates or lush, sugar-rich autumn pastures.
According to DAFM: “This results in a sharp drop in rumen pH as lactic acid accumulates, damaging the rumen epithelium and compromising overall metabolic health.
“Crucially, when unfermented or excess starches escape the rumen and flood the small intestine, they create an ideal environment for the rapid proliferation of Clostridium perfringens type D.
“This overgrowth triggers pulpy kidney disease (enterotoxemia), a rapidly fatal condition caused by toxin absorption.”
Maintaining adequate forage and fibre intake and implementing a rigorous clostridial vaccination programme are described as “vital preventive measures”.
Concentrates must be introduced slowly, starting at low levels and increasing gradually.
Access to clean water source must be maintained.
Parasitic gastroenteritis
The recent rainfall, following a hot dry summer, has rehydrated faecal pellets and grass, allowing infective larvae to move rapidly up the plant.
This can result in acute outbreaks of parasitic gastroenteritis in lambs.
Farmers are advised to closely monitor lamb performance and watch for scouring and poor weight gain.
Devising a safe grazing strategy for susceptible lambs is also an essential part of any parasite control programme.
DAFM stressed that these condition require attentive husbandry measures with careful nutritional and stress management during dietary changes.
It added: “In indoor systems, particular attention needs to be paid to additional potential stressors such as air quality, stocking rates and ectoparasite management.”
Farmers are encouraged to consult private veterinary practitioners to establish preventative health plans.
“In cases of sudden death, prompt post-mortem examinations at an RVL remain invaluable for confirming diagnoses and safeguarding flock health," DAFM said.
