The benefits of One Loft Races (OLRs) include amongst other things :- 1/ OLRs provide a level playing field – loft location, the line of flight and wind direction are all irrelevant with no effect on results. All birds are managed the same and race to the same location. The only difference is the bird’s genetics so, at least in theory, the best birds should win. 2/ OLRs provide fanciers who cannot race their birds, for any reason, the opportunity to compete. 3/ OLRs showcase the sport in a number of ways – they provide a platform to advertise the sport, non- fanciers can become involved in the sport by sponsoring a bird, the significant amount of prize money and the financial value of successful birds help legitimize the sport and introduce a degree of professionalism.
The significant difficulties however that OLRs face are the high mortality rate in young pigeons in the first few weeks after they arrive and the high losses that occur during the events themselves. These difficulties represent significant animal welfare concerns. Unless these issues are addressed in a responsible way, OLRs run the risk of bringing the sport into disrepute. In addition, if the sport comes under serious review (similar to the one just completed with harness racing), it could potentially be shut down. I have spoken to several OLR managers over the last month. One has had over 100 birds die in the previous 3 weeks and at one stage was having 10 die per day. Testing of young birds in OLRs, without exception, shows PMV to be involved while Rota and Circo viruses are often also implicated. I have had friends send birds to OLRs that have died. They were then invited to send replacement birds. When they did this, these birds also died.
A recent paper presented in November 2023 at the International Pigeon Veterinary Association (IPVA) conference in Brussels added a further dimension to the health and animal welfare issues surrounding OLRs. In OLRs, hundreds and sometimes thousands of young pigeons with immature immune systems, which are carrying a whole range of viral (and other) infections, are mixed intimately in a stressful situation. It is an ideal situation for the spread of disease. Into this melting pot comes the issue of viral recombination. Viral recombination occurs when pigeons become simultaneously infected with 2 (or more viruses) or are vaccinated with live vaccines (like the EU PMV vaccine). These viruses simultaneously reproduce themselves at the same time in the same pigeon. During this time, genetic material from both viruses can mix, thus creating a new virus. This situation occurred rarely before the advent of OLRs because the situation where large numbers of young pigeons from many sources mixed intimately just did not occur. What this means is that young pigeons that go to a OLR are not only being exposed to lots of existing known viruses but potentially brand new viruses created at the OLR. A further complication is that, after the OLRs are completed, the surviving birds are sold and distributed, in the process taking any viruses they may have with them. And so what can be done? With PMV being the virus that is universally identified as a significant part of the problem, the starting point is obviously more effective control of PMV.
To this end, the Victorian Racing Pigeon Board (VRPB) proposed the long-overdue PMV nestling trial that was discussed in the previous (February) Journal. It is known that 70% pigeons vaccinated at 6 to 8 weeks of age develop a fully protective immunity in 4 weeks. If the same birds are then given a second shot at this time, fully 100% are immune after a further 4 weeks. At the core of the problem is the fact that, even if pigeons are vaccinated right on 6 weeks of age and receive their second shot at 10 weeks of age, all pigeons are not fully immune until 14 weeks of age. With most pigeons being sent to OLRs from 4 weeks on, they have simply not lived long enough to have had time to be given the vaccines that would protect them. These birds are therefore entering the high-PMV exposure situation at a OLR as vulnerable birds.The recently completed trial investigated whether vaccinating pigeons at a younger age may offer a way of protecting them, either completely or partially, from PMV earlier. In the trial, ten 3-week-old squeakers bred from vaccinated parents and ten 3-week-old squeakers from non-vaccinated parents were selected. Initially these youngsters were bled at 3 weeks of age and then vaccinated. This initial bleed was to check for any immunity in the birds that may have been acquired from their parents or an earlier exposure to the disease. To measure the subsequent level of immunity formed after vaccination, the youngsters were then bled at 4, 5 and 7 weeks of age. In all, therefore, we had four sets of 20 blood results, making a total of 80 tests altogether.
The test used to measure the level of immunity was an Haemaglutination Inhibition (HI) test. In the units used, an HI reading of 3 or higher is sufficient to protect the pigeon from PMV. An HI reading of 1 or 2 shows some immunity. This level will not fully protect the pigeon but will reduce the severity of the disease. For example, rather than dying, the youngster may become unwell for a period of time and then recover or the symptoms may simply be milder. An HI result of zero indicates no immunity. A bird with a reading of zero would therefore be vulnerable to the full effects of PMV.
The results are attached. Table 1 shows the blood test results at 3 weeks of age . The ten young birds bred from non- vaccinated parents all had no immunity. Seven of the ten birds bred from vaccinated birds had a low level of immunity. This is not an uncommon finding, where immunity moves passively from parents to chicks, presumably in the egg and through the crop milk. This parent-acquired “passive immunity” is transient and gives the new chicks some protection as they start their new life. Table 2 presents the blood results from the growing young birds a week later when they were 4 weeks old. The passive immunity from the parents has gone and two of the 20 birds have now started to form their own immunity. With a reading of 2, this level is not enough to fully protect these birds from disease but would be enough to dramatically decrease the severity of symptoms and probably prevent them from dying. Table 3 shows the blood results after another week. The pigeons are now 5 weeks old. Nine birds have now formed their own immunity and two birds have sufficient immunity levels (ie, a HI result of 3) to be completely protected from PMV. Table 4 shows the final set of blood results. Another 2 weeks have passed and the youngsters are now 7 weeks old. Eleven birds have now developed an immune response and eight have HI readings of three or higher – enough to protect them from PMV. So, 4 weeks after vaccinating the birds at 3 weeks of age, nine out of 20 (ie 45%) are immune with the highest immunity level being 4, and a further two birds being partially immune. Significantly, however, nine birds, nearly half the birds, had no immunity. By comparison, as described above, when pigeons are vaccinated over 6 weeks of age, all birds develop an immune response with fully 70% being completely immune within 4 weeks . Also when vaccinated at 6 weeks of age, some birds record immunity levels as high as 9.
The conclusions, as shown in the results, when pigeons are vaccinated at 3 weeks of age compared to over 6 weeks of age are :- 1/ not as many develop protective immunity within 4 weeks of vaccination (45% developed protective immunity when vaccinated at 3 weeks compared to 70% at 6 weeks) 2/ the birds take longer to form their immunity (when vaccinated at 3 weeks, the levels of immunity in birds increased more slowly than in birds vaccinated at 6 weeks of age) 3/ the immunity levels formed are not as high (maximum of HI 4 when vaccinated at 3 weeks compared to HI 9 when vaccinated at 6 weeks ) 4/ the number of birds that developed any immunity after 4 weeks was much lower when vaccinated at 3 weeks compared to 6 weeks. Significantly, nine of the 20 birds, ie 45% vaccinated at 3 weeks, developed no immunity. The number that developed no immunity when vaccinated at 6 weeks was zero – 100% developed some immunity with 70% being fully immune. Put simply, vaccinating birds at 3 weeks of age is not as effective at protecting them from PMV as vaccinating them at 6 weeks of age. There may, however, still be some benefit in vaccinating them then , particularly if the risk of exposure is high, as about half will develop some immunity.
These results may have significant implications for the loft management of many fanciers. It is not unusual for fanciers to give their youngsters their first PMV vaccination at 4 weeks of age as they are being moved from the stock loft to the racing loft. The reasonable inference is that, if 11 of 20 respond at 3 weeks and all birds respond at 6 weeks, the number of young birds vaccinated at 4 and 5 weeks that respond to vaccination would lie somewhere between these two levels. Based on these results, one could therefore reasonably predict that just 14 of 20 would respond if vaccinated at 4 weeks of age and 17 of 20 would respond if vaccinated at 5 weeks. The practice of vaccinating at 4 weeks of age would therefore leave about 1/3 of the young birds with no immunity to PMV. Fanciers who vaccinate for PMV at 4 weeks of age may be lulled into a false sense of security, mistakenly believing that their young birds are protected against PMV when in fact about a third will be totally vulnerable.
So, is it worth vaccinating birds at 3, 4 or 5 weeks of age ? Ideally it would be great if we could wait until the youngest bird in the team was over 6 weeks of age and then give all of the birds their first shot. However, vaccinating earlier can be beneficial, in that at least it would protect some of the birds. This is particularly relevant if there is a risk of a possible PMV exposure before 6 weeks of age. PMV exposure can occur before 6 weeks of age :- 1/ if there is an outbreak of PMV in a nearby loft and the possibility of inter-loft bird mixing while at liberty exists 2/ if birds are being sent to a OLR 3/ if birds are being placed in squeaker sales 4/ if there are loft visitors from other lofts of unknown health status. Fanciers would need to keep in mind, however, that in many of these young birds the vaccine will not “take”. Either no immunity would form or if immunity did form it would not be high enough to be fully protective. Vaccination of birds under 6 weeks of age will, however, protect a percentage of the birds and decrease the severity of disease in others. Fanciers should keep in mind that any immunity is better than no immunity. Fanciers, however, must remember that to fully protect all of their young birds, two vaccinations after 6 weeks of age must be given. In birds where the first shot is given before 6 weeks of age, this will mean, therefore, that some birds will have three shots.
It is worth noting the results of bird No. 5341. Surprisingly, this bird had a value of 2 at four weeks of age but zero at 5 weeks . However, by 7 weeks it was fully immune with a reading of 4. This result presumably relates to the overall immaturity of the birds being tested and an inconsistent response of the immune system to the vaccine.
Recommendation Summary – PMV vaccination Vaccinate all of your birds twice 4 weeks apart with both shots being given after 6 weeks of age. If there is a significant risk of PMV exposure, vaccinate your birds earlier at 4 weeks of age. Recognise, however, that, if this is done, in about a third of these birds the vaccine will not “take” and the team will need to be given three shots for all birds to be protected.
Vaccinating at 3 weeks compared to 6 weeks: can it really make such a difference? As evidenced by the trial results, it is surprising how much just a few weeks difference in age makes to the response to PMV vaccination. I guess when a young pigeon is only 3 weeks old, a further 3 weeks is a relatively a long time. Things happen quickly in a young pigeon’s life. It takes only 18 days, just 2½ weeks, for a pigeon chick to develop from a blob of yolk and egg white into an air-breathing hatching chick with all its organs including a heart and circulation. In the 4 weeks after hatching, it grows from a chick weighing 3 grams, which can sit on a teaspoon, into a full-size pigeon weighing 400 grams that can fly. This is equivalent to the average human baby weighing 4 kg when born growing to 520 kg, just over half a tonne, by 4 weeks of age. So, yes, as shown in these trial results, big changes can occur in the immune system of a young pigeon (and its ability to respond to vaccination) in just a few weeks.
Another suggestion for PMV control: sending OLR entries when they are older. Like most fanciers, I wean my babies into the racing loft at about 28 days of age. At this age, they “home” more easily. Also, the young pigeons have a lot to learn in the months before tossing and racing starts, so perhaps it is best to start this process sooner rather than later. It is also reasonable to think that regular exercise will help them develop physically. But is this really true? Would it make a significant difference if they were sent to OLRs when they were 6 or 8 weeks of age or even older when they had had a chance to develop a higher level of immunity after vaccination. Even if there were issues with subsequent settling in the OLR, this may be preferable to having a significant proportion of the birds actually die soon after arrival. I remember years ago several Australian fanciers wanted to send their birds to the South African Million Dollar race as older birds. They each bred some birds that were transferred to a single loft in Australia. They were “homed”, trained and even tossed to this loft before being sent to South Africa. In the subsequent competitive events, these birds’ rate of return was higher but the number of prizes they won was lower. The fanciers concerned persisted for a number of years but then decided not to continue. Over the years, I have known a number of fanciers who have confined their youngsters to the loft until they were about 8 weeks of age . One did not let them out until the eye colour had changed. When the birds were initially let out, they went everywhere but they quickly learnt to form a flock and within 4 weeks you would not know that they were any different from more conventionally trained youngsters. They also held their own in subsequent racing. So perhaps sending birds when they are older (and more immune) could be an option
Possible criminal conviction Some OLR managers don’t seek veterinary advice, appearing to regard illness, deaths and losses as part of running a OLR. I think that it is important to not simply accept the mortality rate of young pigeons in OLRs. Options need to be explored to reduce this. Quite apart from the reputational damage to the sport, if the situation comes under review and the sport is identified as not doing anything to address the problem, the managers of OLRs might be at risk of criminal prosecution. Under the new animal welfare act, the managers or owners of animals can be prosecuted and have a conviction for animal cruelty recorded against their name if they are found to know that animals under their care are unwell and are at risk of dying and fail to seek veterinary intervention.
Birds that have recovered from PMV It is easy to be distracted by the number of birds that actually die. It is important , however, to remember that birds that are infected and survive can be damaged. These damaged birds have the potential to contribute to subsequent toss and race losses. In addition to other organs, PMV targets the pancreas and kidneys. The effect of this has been discussed at length before but essentially the pancreas controls energy release while the kidneys maintain a normal level of hydration. Some birds that recover from PMV have persistent damage in these organs . Although these birds may look normal on the perch and even toss okay, when it comes to racing their ability to compete, or even just return, is compromised. Also in some birds, PMV will replicate in the brain, causing birds infected, in this way, to develop “twisted necks”. Most of these birds eventually recover clinically and as PMV is only carried in the system for up to 60 days these birds are therefore not persistently infectious and can be considered for breeding. However, my experience with these birds in both Australia and Belgium has been the same. Fanciers advise that, although there is no problem breeding with them, if used as race birds they are quickly lost.
The Future We have a long way to go in Australia to improve the professionalism of pigeon racing. The type of racing that I would like to see has not been invented yet where there is more cooperation and a better system for sharing information. One thing is for certain, we do need to address the issues of youngster mortality and race losses associated with OLRs. Although it would have been great if pigeons vaccinated at 3 weeks of age could react similarly to those vaccinated at 6 weeks, it appears that the immune system at this age is too immature to respond to the immune challenge provided by vaccination. Vaccinating birds younger than 6 weeks and as early as 3 weeks of age does have benefits but comes with restrictions. It is part of the answer to PMV control in high-risk situations such as in OLRs but, by itself, is not sufficient to solve the problem. The recommendations that I make to OLR managers have been discussed in earlier ARPJ articles and include asking fanciers to vaccinate their entries at 3 weeks of age before shipping, using PMV RATs as a diagnostic tool when birds arrive, rejecting birds that look unwell, screening birds with PMV HI tests and PCR tests and revaccinating 2 weeks after the first vaccination (rather than 4 weeks). Other OLR investigations have been proposed to the VRPB and the Australian fancy, which may offer further insights into control. The ANRPB holds fancier funds that could be used to address the health issues associated with OLRs. The VRPB next meets in March and will discuss these matters .
The Racing Pigeon Magazine – End of an Era I am disappointed to report that the British weekly pigeon newspaper, “The Racing Pigeon”, has announced that it is closing down. This publication is internationally known and has been an icon in the British racing pigeon sport. The company announced that the last magazine will be printed on 28 June 2024, exactly 125 years after it was first published. The company will continue publishing The Racing Pigeon Pictorial but, instead of this glossy picture-filled magazine being published monthly, it will now be published quarterly. In my opinion, it would be a great shame if our own Australian national magazine, the Australian Racing Pigeon Journal, was forced to go the same way. National magazines are an important part of the pigeon racing landscape. It is important for Australian fanciers to realise that magazines need subscribers to remain viable. It is therefore vital that they continue to support the ARPJ. It can be hard enough at times to get current and accurate information out to fanciers. The loss of our national magazine would further compromise this ability. I urge all Australian fanciers to continue their support of our publication.
Pigeons donated to the University of Melbourne For the tenth year in a row, VHA members have donated pigeons to the University of Melbourne. The birds are used to teach final-year veterinary students basic handling skills, as well as how to perform basic veterinary skills such as blood collection and crop flushing. The VHA is pleased to offer support to the University in training the budding avian vets of the future. I would like to offer a special thanks to Stevan Gazzola of Meadow Lofts in Melbourne who donated 20 of the 30 birds required.
Is that pigeon with PMV likely to survive? When pigeons become infected with PMV, the virus can invade many different parts of the body, including the pancreas, bowel, brain and kidneys. The signs displayed by infected birds are, to some extent, determined by which organs are affected. Some pigeons just become quiet and fluffed with loose droppings and don’t want to eat. Others, however, become very thirsty, drink a lot and develop extremely watery droppings with a high urine content and have enlarged fluid-filled crops. I have had a number of fanciers whose birds have caught PMV tell me that, once birds become thirsty and develop fluid-filled crops, they are much more likely to die. These symptoms occur when the virus affects the kidneys. Once the virus gets into the kidneys, it damages them. This damage compromises the ability of the kidneys to maintain their normal function of concentrating the urine and maintaining normal hydration. With body fluid continually being lost, the birds become thirsty, drink often and have fluid-filled crops. Large watery urine-based droppings appear on the floor. As the virus continues to damage the kidneys, this can progress to the point where there is no longer sufficient healthy kidney tissue left to maintain normal function. The bird then goes into kidney failure and in most cases will die. As our knowledge and direct experience with PMV continue to grow, we continue to learn. It does, however, seem that the symptoms of a thirst and fluid-filled crop are serious signs and can be used by fanciers as an indication of whether an affected bird is likely to survive or not.
Vet Questions 1/ I have had PMV diagnosed in my birds. A friend has suggested that I treat them with Virkon in the drinking water. Is this a good idea? Virkon is a disinfectant. Some fanciers believe that because it kills bacteria and viruses in the environment that it will also do this internally if ingested. PMV is a virus that can become widely distributed throughout the body including the kidneys, pancreas and brain. The idea that drinking a disinfectant like Virkon will kill PMV inside the cells in all of these remote body places is just nonsense. It is a bit like the way that Donald Trump suggested using bleach internally to treat Covid 19.
2/ When separating breeding pairs, is there any way of stopping the hens from laying eggs all summer, without long term effects? Unfortunately there is no easy natural way of doing this . As day length shortens and the temperature decreases the pigeons hormone profile changes. This leads to a decrease in reproductive behaviour and the start of the moult. Triggers for breeding include long warm days , the presence of a cock or hearing cocks nearby and anything that the hen may associate with breeding such as a nest box, a nest bowl or nesting material. Removing from the loft any obvious triggers as well as darkening the loft by 15 minutes every second day until the period of light is less than 8 hours may all help. Pigeons however are non- seasonal breeders and there will be some hens that despite all efforts will continue to lay. In a veterinary sense there are drugs we can use. The most common is a GNRH ( Gonadotrophin Releasing Hormone ) blocker called Supraloerin. This is available as a pellet that is injected under the skin. The pellet gradually dissolves. As it does this it gradually releases the drug into the system. The drug works by blocking the release of hormones from the pituitary gland in the brain that tell the ovary to ovulate. The pellets have the potential to last up to 6 months but response to treatment is variable from one bird to another with ovulation in some birds being blocked for a shorter time. The pellets are expensive and cost over $100 each. There main use is to block ovulation in individual birds of value which need a reproductive rest after a reproductive problem such as egg binding or an oviduct infection. I have always thought it a shame that these pellets were not cheaper. It might be good if we could put one into all of the race hens at the start of the season.
3/ What is the root cause of “Going Light”? Is there a recommended treatment regime” “Going Light” is a term that was used before we had the knowledge of pigeon disease that we have today. The term just means a thin pigeon . A pigeon that had lost weight was said to have “going light”. Weight loss can be due to many many things ranging from problems that might cause weight loss in flocks such as viral, bacterial or parasitic infections through to problems that affect individual birds like cancer. There is no universal treatment for weight loss. It would be great ( and a bit amazing ) if there was a magic bullet that treated all of the diverse causes of weight loss. Once the cause is identified than a treatment in that instance can be given. These days “going light” should be regarded as a symptom rather than a diagnosis. Other similar “diseases” from the past include “roup” and “sour crop” which were used to describe birds with difficulty breathing and delayed crop emptying respectively no matter what the cause.