Revealed: The 5 main causes of calf deaths this spring

The Irish dairy herd has expanded considerably in recent years. With this growth comes concerns about calf health, mortality and welfare.

Recent work, carried out by Teagasc’s John Mee and Jonathon Kenneally, has identified the primary causes of calf deaths on dairy farms this spring.

The study, which was carried out on commercial dairy farms in Munster, found that a lack of oxygen during unobserved, prolonged and difficult calvings was the main cause of calf mortality.

The research work tried to identify the cause of death for 259 stillborn calves. The majority of the calves involved in the study (59%) were sired by Holstein Friesian AI; a further 28% were sired by natural service.

The calves’ dams were in normal body condition score (BCS) and calved at term (279 days); approximately 38% of the calves involved in the study were born to heifers.

Key results

The top five reasons why calves die at calving:
  1. A lack of oxygen (anoxia) during prolonged, unobserved calvings;
  2. Calves not presented correctly – difficult calvings;
  3. Birth defects – calves with a blocked bowel or ‘waterbelly’;
  4. Hemorrhage or anemia – bleeding before/during calving;
  5. Placenta separating prematurely.

The study found that where calving was not observed, the main causes of death were a lack of oxygen, hemorrhage/anemia and birth defects. Unobserved calvings also had the highest incidence of unexplained stillbirths.

In addition, for calves that die during a hard calving, the main causes of death were malpresentation, a lack of oxygen and pre-existing congenital defects.

In contrast, the study found, for calves that die at an observed but unassisted calving, the main causes of death are birth defects, a lack of oxygen and hemorrhage/anemia.

Causes of death in calves in each calving assistance category:

Image source: Teagasc

Recommendations

The Teagasc study found that the causes of calf deaths differ between unassisted and difficult calvings; anoxia was the predominant cause in the former and malpresentation in the latter.

Teagasc says that farmers can reduce mortality by selecting low calving difficultly beef sires; recording stock bull service dates; scanning cows for twins and foetal sex; improving calving supervision; and by using the results from calves submitted to the local Regional Veterinary Laboratory.