Co-Authors:
Brosh, A., Department of Zoology and Institute for Nature Conservation Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, 69978, Tel Aviv, Israel
Sneh, B., Department of Zoology and Institute for Nature Conservation Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, 69978, Tel Aviv, Israel
Shkolnik, A., Department of Zoology and Institute for Nature Conservation Research, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, 69978, Tel Aviv, Israel
Abstract:
Drinking regimes of Bedouin goats affect their feeding behaviour and the ruminal environmental conditions, as expressed by changes in osmotic pressure as well as in pH of the rumen content. The osmotic concentration of the rumen content of a goat drinking once daily was 330 m-osmole/kg just before drinking. After water deprivation for 4 days, the osmotic concentration reached 360 m-osmole/kg and, immediately after excessive drinking, decreased to 82 m-osmole/kg. After a short while, the osmotic concentration increased to 300 m-osmole/kg and after 13 h reached the peak of 440 m-osmole/kg, mainly owing to the release of degradation products. The pH was also affected by food consumption. Just prior to drinking, the pH in the rumen of dehydrated goats was 6.9. It decreased to 6.0 after excessive drinking and feeding. Later, it ranged between 6.4 and 7.1. Most of the microorganisms in the rumen are attached to the fibres fraction. No difference could be observed in direct bacterial counts in the fluid fraction between dehydrated and goats drinking daily. However, the number of protozoa was reduced in dehydrated goats, especially after excessive drinking, as some species of protozoa seem to explode in a hypo-osmotic ambient. The fermentation capacity of the fibres fraction was higher than that of the fluid fraction, indicating also the presence of more microorganisms in the fibres. In addition, the osmotic changes occurring during the dehydrationrehydration cycles had no significant effect on fermentation capability of the rumen microorganisms. At a low osmotic concentration in an NaCl deficient ambient, there was some decrease in fermentation rate, but this could be nullified with the addition of NaCl, which is required for microbial activity. The decrease in fermentation rate is not due to its effect on the osmotic concentration. The microorganisms in the fibres fraction were found to be less affected by NaCl deficiency in the ambient medium. This research was partly supported by the International Atomic Agency, Vienna. We would like to thank A. Tadmor, Institute of Veterinary Science, for his valuable assistance in the goat surgery. © 1983, Cambridge University Press. All rights reserved.
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