The agricultural economics literature, both academic and trade, has discussed theassumed presence of cycles in livestock markets such as cattle and hogs for a very longtime. Since Jarvis (1974), there has been considerable discussion over how these cyclesimpact optimal economic decision making. Subsequent studies such as Rucker, Burt, andLaFrance (1984), Hayes and Schmitz (1987), Foster and Burt (1992), Rosen, Murphy, andScheinkman (1994), and Hamilton and Kastens (2000) have all investigated some aspectof how biological factors, economic events, or economic actions could be causes of and/orresponses to cycles in hog and cattle inventories. There has also been debate, again bothin the academic and trade literature, over the length of the cycle(s) present in hog andcattle stocks. To provide both academics and producers with accurate information on thenumber and periods of cycles that might be present in hog and cattle inventories, thispaper provides a purely statistical view of the matter.Using over 140 years of annual data on cattle and hog inventory levels, we estimateBayesian autoregressive, trend-stationary models on cattle inventories, hog inventories,and the growth rate of cattle inventories. We then use those models to find the posteriordistributions of both the number of cycles present in each series and the period lengths ofthose cycles. We find multiple cycles present in all three series. Cattle inventory resultsshow clear evidence in favor of 4.5, 6, and 11 year cycles with other cycles present but not asclearly identified. Hog inventory results identify five cycles with periods of approximately4.5, 5.4, 6.8, 10 and 13 years. The data on the growth rate in cattle stocks has similarcycles to the series on the stock levels.
