Premature Lactation in Exported Dairy Cattle – Further Research

Summary

Young dairy cows can get enlarged udders and produce milk even if they are not pregnant. In the live export industry, this can create confusion for overseas buyers, and they may end up being sent to an abattoir when they arrive instead of used for breeding. It also can put an animal at an increased risk of infection (mastitis).

The cause of this condition, known as premature lactation, is poorly understood. This project tested a theory from previous research, which suggested it was due to the growth of toxic fungi (mycotoxins) on the pellets fed to cattle on export ships.

There was very little of this toxin, zearalenone (ZEA), found in the feed samples tested, even though premature lactation occurred on those voyages, so more investigation is needed on the risk factors associated with the condition.

Objectives

This project aimed to collect samples of feed at different points in the livestock export process and test them for mycotoxins, and compare this to whether premature lactation occurred on the ships where that feed was used.

Key findings

• Only three of the 36 samples of feed showed detectable levels of any mycotoxin (namely aflatoxin), and none had ZEA.
• There was no premature lactation reported on one of the shipments where feed was collected, while information was not available for the second voyage.
• Given the presence of toxic fungi in feed does not appear to be as common as originally believed, it may be less likely to be associated with premature lactation in dairy cattle on live export voyages as previously thought.

Benefits to industry

Identifying the cause of premature lactation in exported dairy cattle on long sea voyages will help to reduce the welfare issues associated with the condition, as well lessen the likelihood the animals are rejected as breeding stock in destination countries.

MLA action

To initiate projects that determine case history by standardised data collection. To gather data and understand frequency and time of year premature lactation occurs.

Future research

Researchers re-stated recommendations from their earlier study, that collecting more data on board ships will help to identify which animals, under which conditions, are more likely to experience premature lactation.

The report also suggested land-based trials, feeding the pellets used on ships to dairy cows of a similar type to those exported, to see if there is evidence of premature lactation.