Monday, July 27, 2009

consequences of 'genetic engineering' rather than intended genotype outcomes.

You are correct in that these alarm bells are aimed at the physiological consequences of 'genetic engineering' rather than intended genotype outcomes.

The point is that the risk of these physiological consequences is causing livestock industries to take a step back and review breeding objectives aimed at productivity increases. I'm suggesting the alpaca industry should be one of them.

You are correct Neil in that the dairy cow problem relates to a massive daily nutrient drain that is required for increased milk yields. However, the daily nutrient drain for fiber production in alpacas is surprisingly high, particularly protein.

The amount of met. protein required for daily fiber production of, say, 8 grams per day is about 50g. The daily maintenance requirement for adult (dry) alpacas is about 250g. If fiber production doubles, then the amount of protein requirement is a massive 40% (about) of the amount required for maintenance. I don't think this would have a significant affect on a healthy alpaca experiencing low/no levels of stress.

However, the increased demands on available protein (and energy) would play havoc at times of stress, particularly foetal development, lactation and muscular development.

This is what we are now starting to find in the wool industry. The problems associated with focused genetic gains for increased productivity are not apparent under normal circumstances, but can have horrendous consequences when the sheep are placed under stress - Sheep that have been bred with extremely high fleece weights are found to have inferior coping ability under abnormal conditions. As I mentioned in my last post, these observations, however, are not frequent at this stage in the merino industry.

In conclusion, these comments are in no way to be taken as a criticism of breeding for follicle density. The comments actually are in response to previous comments on the need for a balanced approach to breeding objectives. In a nutshell, the issue of accelerated genetic improvement for productivity gains raises the need to take a deep breath and consider the potential negative ramifications of such breeding goals. Further, these considerations should be at both the industry and individual level.

Paul Vallely

the reference we use for nutritional requirements. It is 'Nutrient Requirements for Small Ruminants', National Research Council. US. There are a number of sections on Camelids.

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