Thursday, February 25, 2010

Effect of breeding on molt

Breeders of shamas may know that a bird that has been bred during the year will likely have a molt that is not as good as a bird that has not been bred. I recently came across a research paper that sought to explain why this is so. The reason offered was that breeding and molt cause great stress to the bird and as the molt takes place at the end of the breeding season, the bird is in a weakened state as it enters the molt. Also, if the bird is bred late in the season, the time available for molt will be reduced. In other words, the bird will need to complete its molt within a shorter time than a bird that has not been bred.

I would accept that the bird that has been bred will have depleted its its bodily resources that are required for a good molt. However, I am not sure that the researchers are substantially correct in their hypothesis and conclusions that the period of molt is reduced, at least for birds that molt in the tropics.

The research was done in the West where there are 4 seasons but I have noticed that even in the tropics where there is no winter, the breeders tend to have an inferior molt as compared to the non-breeder. It is true that even in the tropics, there is a season of sorts and there is the monsoon or cool "season" towards the end of the year but I doubt if it has the effect of shortening the period of molt.

I would venture to think that the cause of breeders having an inferior molt is not so much the reduced period of molt but rather that breeding and molt place great stress on the bird's physiological system and they have not fully recovered when the molt commences.

During breeding, hormonal changes take place in both the male and the female. These hormones are different from the hormone required for molt. At the end of the breeding season, some of these hormones can be expected to still linger in the bird's system. Consequently, before the hormones for molt have fully had had time to properly replace the hormones required for breeding, the feathers have started to change under less than ideal conditions.

Bear in mind that feathers are comprised largely of protein and form about 20% to 25% of the body weight of the bird. In the circumstances, it is no wonder that the bird that has been bred, is likely to have an inferior molt.

There are of course things that we can do to assist the bird to have a good molt. Stopping the pair from breeding will allow some time to lapse before the molt so that the bird can build the reserves required for molt. I would also separate the pair. This has the effect of keeping the male's form at a higher level than if the pair are left together and this helps to delay the molt during which time, the bird's system can better prepare itself for molt. As feathers are made up largely of protein, a diet rich in protein will also help.

1 comment:

  1. Very useful info. I would think it is true. Some local breeders of doves have noted that left alone, some of their birds actually died from being too weak when bred non stop.