The state of Vermont in the US would likely greet Luigi’s news about less flatulent fodder with horror, if there were any Acacia or Sesbania there. Vermont has one of the fastest-growing alternative energy programmes in the US, all based on the prodigious output of its vast dairy herd. Better yet, methane is a much more effective greenhouse gas than carbon dioxide. So burning methane is win-win: less methane, and less carbon dioxide than non-renewable power-station fuels. via Grist.
Cutting down on cow emissions
Methane is a powerful greenhouse gas and ruminant farm animals belch out a huge amount of the stuff. No wonder people are scouring agrobiodiversity for animal feeds that minimise emissions. A paper in Animal Feed Science and Technology ((C.R. Soliva, A.B. Zeleke, C. Clement, H.D. Hess, V. Fievez and M. Kreuzer. In vitro screening of various tropical foliages, seeds, fruits and medicinal plants for low methane and high ammonia generating potentials in the rumen. Animal Feed Science and Technology. Corrected Proof, Available online 18 October 2007. http://dx.doi.org/10.1016/j.anifeedsci.2007.09.009)) has come up trumps. The researchers found differences in methane production not just among tropical feed species, but also among accessions of Acacia angustissima and Sesbania sesban. Something to add to the list of evaluation descriptors.
Giant African snail both treat and menace
African mini-livestock species runs amok in Brazil.
Turning market waste into meat and milk
A recent paper in Animal Feed Science and Technology ((C.B. Katongolea et al. (2007) Nutritional characterization of some tropical urban market crop wastes. http://dx.doi.org/10.1016/j.anifeedsci.2007.09.002)) did a number on three different kinds of waste from the markets of Kampala, Uganda. Waste from banana, sweet potatoes and Solanum aethiopicum (African eggplant) were chemically analyzed and fed to sheep and goats. That way, the scientists could measure what the wastes contain and how much of that the animals could make use of. Turns out — surprise — that there are differences among the wastes and differences between wet and dry season wastes. Banana leaves and pseudostems were not all that nutritious, and African eggplant leaves were very watery. But sweet potato leaves were just right: “sufficient to provide the CP (crude protein) and ME (metabolizable energy) required by growing goats under tropical conditions”.
Which is nice to know, but not all that surprising, given that about half the sweet potato crop in China is fed to livestock. Of course, pigs are monogastric, while sheep and goats are ruminants, so it was worth checking.
Will this see the market people of Kampala bundling sweet potato waste for sale? Or maybe the farmers will grow the leafy varieties specifically for animal fodder.
Reinventing the wheel
More evidence of multiple independent domestication events. Previous work has shown such a pattern for rice in Asia and cucurbits in the America. Now it’s the turn of barley in Eurasia. A paper just out ((Saisho, Daisuke, Purugganan, Michael. (2007) Molecular phylogeography of domesticated barley traces expansion of agriculture in the Old World. Genetics.)) looked at both sequences of 5 genes and also morphological traits in a geographically widespread set of 250-odd landraces. ((From a Japanese university genebank.))
The results suggest that the crop was first domesticated 10,000 years ago somewhere in the Fertile Crescent, from whence it spread to Europe, North Africa and Ethiopia (the material from Ethiopia was somewhat distinct, as has already been documented). However, there was apparently also a second domestication, much later. It occurred in the region encompassing southern Central Asia, the eastern Iranian plataeau and the edge of the Indian subcontinent, and it is material from here that spread eastward starting maybe 2,500 years ago, possibly along the Silk Road, to give rise to the barleys of India, the Himalayas and China.
This is not an unusual pattern in Eurasian agricultural biodiversity. Sheep and cattle DNA data also show “two highly divergent lineages that distinguish European and Asian types, indicating a second independent evolution of these livestock species outside the Near East.” Not unusual, but somewhat puzzling. As the barley authors conclude:
It remains unclear why different cultures sought to re-invent these domesticated species several times rather than simply obtain them through diffusion from other farming societies.
The authors of the barley study speculate that the second domestication happened either because of the transmission of knowledge, or as an independent innovation. I find the second option a bit hard to take. Could it be that the results of the first domestication effort were just not adapted to conditions outside the Fertile Crescent, or there was a barrier to their diffusion? Or maybe it was just a matter of pride for the inhabitants of the Iranian plateau to have their own agrobiodiversity?