Joint Irish Setter Breed Clubs

Statement on the control of the rcd4 mutation in Irish setters

The Joint Irish Setter Breed Clubs (JISBC) have drawn up the following guidelines for the control of the recently discovered rcd4 mutation which causes Late Onset Progressive Retinal Atrophy (LOPRA) in Irish Setters. Whilst it should be stressed that clinical signs of LOPRA usually appear after the age of 9 years, the JISBC still believe it to be a welfare issue, although it is noted that many dogs can cope with blindness.

Data from the Animal Health Trust so far suggest the prevalence of carriers of the rcd4 mutation (i.e. heterozygotes) in the breed is about 42% and therefore the proposed guidelines are considered appropriate at this time. The JISBC recognises the need to maintain genetic diversity within the breed and does not yet recommend a complete ban on breeding using carrier or affected dogs.

However, the principle of these guidelines is that no dogs should be produced that will develop PRA and become blind, and therefore all members of the JISBC agree that:

1. All caring and responsible breeders will test their stock before planning a mating.

• Any rumour and supposition about a dog’s genetic status should be ignored; DNA-testing should be undertaken.
• As DNA-testing is now available, ‘hereditarily clear’ dogs will be produced. However such dogs should still be tested before being used for breeding because of the potential difficulty in proving parentage.
• If the rcd4 status of any stud dog, or its semen, is unknown then the bitch to be mated must be tested and found CLEAR.

2. AFFECTED dogs (i.e. homozygous for the rcd4 mutation) should never be mated with other AFFECTED dogs as all progeny will be AFFECTED.

Thus the following are recommendations about potential matings that the JISBC consider acceptable at this time:

• CLEAR x CLEAR matings are encouraged.
• CLEAR x CARRIER* matings: progeny will, on average, be CLEAR (50%) or CARRIERS (50%) and should be DNA-tested before breeding.
• CLEAR x AFFECTED* matings: all progeny will be CARRIERS.

* It is recommended that any use of AFFECTED and CARRIER stud-dogs is given serious, cautious consideration by both stud-dog owners and breeders before planning a mating.

Purchasers of any dogs produced by CLEAR x CARRIER and CLEAR x AFFECTED matings should be advised that these dogs will not develop PRA rcd-4, but should not be used for breeding unless tested.

All breeders should note that AFFECTED x CARRIER or CARRIER x CARRIER matings may produce some AFFECTED dogs.

1. CARRIER x CARRIER matings will produce, on average, 25% AFFECTED progeny.
2. AFFECTED x CARRIER matings will produce, on average, 50% AFFECTED progeny.

Purchasers of any dogs produced by such matings should be advised that some of these dogs may develop PRA rcd-4 and should not be used for breeding unless DNA-tested.

The JISBC will continue to monitor the prevalence of the rcd4 mutation within the breed. However it is aware that a further PRA mutation that causes blindness at an earlier age (so-called mid-onset PRA) may be present in the breed but has yet to be confirmed and characterised genetically. Thus control measures for rcd4 may need to be modified if this new form of PRA is prevalent, as the earlier onset of blindness clearly has an even greater welfare implication.

Signed on behalf of the following breed clubs, which endorse and support these recommendations

Belfast & District Irish Setter Club
The Irish Setter Association England
The Irish Setter Breeders Club
The  Irish Setter Club of Scotland
The  Irish Setter Club of Wales
The  Midlands Irish Setter Society
North-East of England Irish Setter Club
The  South of England Irish Setter Club

Professor EJ Hall

Chairman, Irish Setter Breed Clubs Health Coordinator Group

29 February 2012