Fatty Liver Syndrome Necropsy Workshop

14 October 2019

Fatty liver syndrome occurs in laying hens and breeders mainly around peak poduction and at the end of the laying cycle. It can result in a significant drop in egg production, have a negative impact of egg shell quality and can increase mortality.

Fatty live syndrome is caused by an increased high fatty acid synthesis in the liver and an inadeqaute transport of these fatty acids out of the liver, leading to a accumlation of fats in the liver cells. This can lead to liver damage and enlargement, causing a weaker blood vessel system in the liver.

Birds most susseccptible

The liver is critical for fat synthesis in birds, and therefore the liver is very active in birds producing eggs. Fatty liver syndrome is more common in high producing birds, due to their very active ovaries and the production of high levels of estrogen. The most common occurance of fatty liver syndrome is found in the following;

Young layers, age 20-28 weeks, at peak production due to;

• High laying percentage

• High estrogen production, resulting in higher fat production in liver

• Negative energy balance

Older layers, age 50-55 weeks;

• Laying percentage goes down

• Energy intake gets too high

• Transport of fatty acids out of the liver can’t match influx


Diagnosing Fatty Liver syndrome

Fatty liver syndrome can result in the following clinical symptons:

• An increase in body weight (admonimal fat).

• A drop in egg production.

• Mortality up to 5-10% (Mortality is caused by internal bleeding as the hen is straining to lay an egg).

• Pale to yellow combs

• Sunken eggs


If Fatty liver syndrome is suspected, diagnoses can be made by necropsy. Enlarged, pale and friable livers with abnormal amounts of fat in the abdominal cavity will be found. Livers of affected birds become very fragile and liver bleedings are commmon. A liver fat percentage in birds suffering from Fatty liver syndrome can be as high as 70%.


Liver Necropsy workshop July 2019

The fatty liver necropsy workshop was held in Agrihealth Veterinary, Co.Monaghan. The necropsy workshop was conducted by Farm-O-San’s Technical Specialist Hubert Smeets. A selection of birds from multiple sites including brown layers from both enriched cages (57 and 78 weeks) and free range systems (43-78 weeks) were necropsied. Additionaly two samples of Ross broiler breeder birds aged 52 and 55 weeks were necropsied. The necropy worskhop was carried out according to the Farm-O-San Necrosy Guide for Fatty Liver Syndrome and Trouw Nutritions liver colour card scoring system.

 Cage birds

The cage birds asssed were from two different production sites and were 57 and 76 weeks of age. It was quiete evident from the necropsy that both samples of birds had strong evidance of Fatty Liver syndrome, showing 100% prevalance. Both samples showed friable and yellow coloured livers, with evidance of blood spots and excess abdominal fat.


Free range birds

The free range birds asssed were from multiple different production sites and ranged from 43 to 78 weeks of age. The prevalance of fatty liver syndrome in the free range sample of birds was 50%, with samples showing liver colour discolouration, friability and excess abdominal fat.