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Calcium-Containing Crystals in Alfalfa: Their Fate in Cattle^{1 ,2,}

Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506

John J. Blaha

National Measurement Laboratory, National Bureau of Standards, Washington, DC 20234
and Department of Chemistry, Kansas State University, Manhattan 66506

ABSTRACT

The fate of crystals in the parenchymatous sheaths around vascular bundles in alfalfa leaves was followed through the bovine digestive tract by scanning electron microscopy. The bundle and sheath pass from the rumen largely intact. Most crystals are released from the bundle sheath postruminally. In feces, some crystals appear partially eroded and others are intact. By energy-dispersive x-ray analysis calcium is the primary crystal cation.

Intact crystals isolated from alfalfa leaves by low-temperature ashing and from bovine feces by washing and differential specific gravity were subjected to Raman microprobe analysis. Most crystals were calcium oxalate, a few were potassium oxalate, and some contained both compounds. From 20 to 33% of calcium in alfalfa is in the form of oxalate and apparently unavailable to ruminants. Carbonate is probably in partially eroded crystals from feces. Data presented account for the poorer utilization by cattle of calcium from alfalfa that that from inorganic sources.

¹ Contribution No. 79-75-j, Department of Animal Sciences and Industry, Chemistry, Kansas Agricultural Experiment Station, Kansas State University, Manhattan 66506.

² Certain commercial equipment, instruments, or materials are identified in this report in order to adequately specify the experimental procedure. In no case does such identification imply recommendation or endorsement by the National Bureau of Standards, nor does it imply that the material or equipment is necessarily the best for the purpose.

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