PULMONARY HYPOPLASIA AND ANASARCA
IN AUSTRALIAN DEXTERS

The Pulmonary Hypoplasia and Anasarca (PHA) gene is present in the Australia Dexter herd.  If breeders do not mate a carrier animal to another carrier animal there will be no problem associated with this condition in their individual herds.

​

PHA is due to a recessive gene. This unfortunately means that the animals that carry the gene show no outward sign of the problem.  The only way to know if an animal is a carrier is to have the animal tested for the genetic marker.

​

PHA is the condition where the lungs do not develop as they are growing in utero.  Affected calves are born dead with minimal or no lung tissue in their chest cavities.  The affected calves also show a marked accumulation of their tissues throughout their bodies giving them a grossly enlarged appearance.  Unfortunately affected calves tend to go full term and the cows carrying them often need help, generally a caesarean or a difficult manual delivery, to deliver them as they can be very large and cause calving problems.

If two non-carrier animals (NN) are mated, all the resulting calves will NOT carry the condition.

​

NN x NN = 100% NN

If a carrier (Nn) animal is mated to a non-carrier animal (NN), 50% of the calves will be non-carriers (NN), and 50% of the calves will be carriers (Nn).

​

Nn x NN = 50%NN and 50%Nn

If two carrier animals (Nn) are mated, 25% of the calves will be non-carriers (NN), 50% will be carriers (Nn), and 25% will be affected and have the condition (nn).

​

Nn x Nn = 25%NN, 50%Nn, and 25%nn

​

By having animals related to known carrier animals tested, and by following a sensible breeding program of not breeding two carrier animals together, it will be possible to have all calves born not affected by PHA and avoid the calving problems associated with the condition.

​