Periodicity in tree rings from the corn belt

Previous tree-ring studies indicated that the total area affected by drought in the western United States has rhythmically expanded and contracted over the past 300 years, with a period near the 18.6-year lunar nodal and 22-year double-sunspot cycles. Recently collected tree-ring data from the U.S. Corn Belt for the years 1680 to 1980 were examined for evidence of either of these cycles on a regional scale. Spectral analysis indicated no periodicity in the eastern part of the Corn Belt, but a significant 18.33-year period in the western part. The period length changed from 17.60 to 20.95 years between the first 150 years and the last 151. High-resolution frequency analysis showed that the structure of the 18.33-year spectral peak was complex, with contributions from several frequencies near both the lunar nodal and double-sunspot periods. A t-test of difference of means in reconstructed annual precipitation weakly corroborated a previous finding of an association between drought area and the phase of the double-sunspot cycle. Both the high-resolution frequency analysis and the t-test results indicate that the periodic component of drought near 20 years is too weak and irregular to be of use in drought forecasting for the Corn Belt.     

A nutritional myopathy enzootic in a group of yearling beef cattle

Steers and bulls under feedlot conditions and on an apparently adequate ration developed transitory signs of diarrhea and unthriftiness. One animal became recumbent. Sick and clinically normal animals in the group had elevated serum creatine kinase and aspartate aminotransferase enzyme values and degenerative changes in muscle fibers on biopsy. Feed analysis was carried out and the animals were monitored over several weeks by means of muscle biopsy and serum enzyme analysis as well as by postmortem examination at slaughter. Subclinical myopathy was found in several animals and was thought to be related to low vitamin E content in the high moisture corn ration.     

Congenital esophagotracheal fistula as the cause of bloat in a calf

A four day old Holstein calf was presented with a history of recurrent free gas bloat. An exploratory laparotomy was performed and no abnormalities were discovered in the gastrointestinal tract. An esophagotracheal fistula was suspected and confirmed by endoscopy. Surgical correction was performed by ligating the tubular connection between the trachea and esophagus and suturing closed the defects in these structures.