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28 November 2003

E-Bulletin Backscatter

SAS in Pakistan

Dear Dr. Carlson,

The Karachi Grammar School chapter of the SAS is a big success. We have lots of activities in our plans. Currently we are organizing a science fair and encouraging people to participate in it. The local chapter has selected the best students as its council members. I have three other officers and around eighteen council members. There are many more people interested but too large a council would make it too cumbersome. SAS is among the most respected societies in KGS. I hope everything turns out well.

The office bearers are as follows:

Yassir Rizwan (me), President
Ali Zaki, Vice President
Saad Rizvi, Secretary
Mustansir Jivanjee, Treasurer

Thanks for all your support and time,

Yassir Rizwan

Sheep vs. Cattle

Forrest Mims implies that cattle over graze pastures and sheep do not. This is incorrect. It is the ratio of the amount of forage present to the number of animals stocked that does the damage be it cows, sheep, pigs, or whatever.

In fact, sheep require much more careful management than cattle as they graze in tight flocks and graze very close to the ground and can damage the range grasses in an area much faster than cattle will, as they range over a much wider area in the same time frame than sheep will. Hence a sheep herder is needed not only to protect the sheep but to take them to the proper pastures to prevent them from over grazing.

Sheep also carry more parasites that are pathogenic to humans than cattle do. It is seldom I hear of a serous problem from nematodes in humans caught from cattle but a whole family got liver flukes that were traced to sheep. They ate frog legs in the summer when the ponds were low from a pond where poorly medicated sheep had grazed that year. They infected the pond with nematodes that took up residence in the bullfrogs and then humans, settling in their liver. Fortunately there was a doctor practicing there that had seen it and diagnosed it in one member and snatched them from death's door in a matter of days with the proper treatment.

You can damage range land with any plan you chose if you implement incorrectly. Goats are the best fit for large areas of Texas as they prefer weeds and brush over grass. Only a very few pastures meet the picky palette of the sheep and the fact that they resemble food for many Texas predators.

Gordon Couger

Forrest Mims replies:

Gordon Cougar writes, "Forrest Mims implies that Cattle over graze pastures and sheep do not is incorrect. It is the ratio of the amount of forage present to the number of animals stocked that does the damage be it cows, sheep, pigs, or what ever."

There wasn't space in the column to discuss livestock-to-forage ratios, and the only implication was that a sheep consumes much less forage than a cow. In my region, the rule is that one cow requires the equivalent forage of five sheep. Our place is small, and we placed one ram and four ewes on land formally grazed by 3-5 mature cows. The sheep were far less destructive than the cows, which had consumed virtually all the reachable vegetation and caused soil erosion. After the sheep arrived, overgrazing promptly ended, erosion stopped and the population of fire ants fell sharply. Reducing the cattle to a single cow would have stopped overgrazing, but, at least on our place, only one cow caused much more soil erosion down by the creek than half a dozen sheep.