No abstract

The techniques used to mitigate the effects of heat stress on lactating dairy cows are often overwhelmed in the southeastern United States, where elevated heat and humidity often persist for extended periods. A model free-stall barn located at the North Mississippi Branch Experiment Station in Holly Springs was used to evaluate the potential of tunnel ventilation with evaporative cooling to alleviate heat stress in lactating dairy cows. Two studies were conducted using 2 groups of 10 lactating Holsteins housed in the tunnel barn (inside) and 2 groups of matched herdmates housed in an adjacent covered free-stall barn (outside), which was cooled by fans and sprinklers during 2001 or by shade and fans alone in 2003. Peak daytime temperatures inside were 5.2 +/- 0.18 degrees C below that outside in 2001 and 3.1 +/- 0.20 degrees C lower in 2003. Although evaporative cooling increased humidity by 22%, cows housed in the tunnel barn received 84% less exposure to moderate heat stress (temperature-humidity index > 80) in both years. Cooling cows with evaporative tunnel ventilation reduced respiration rates by 15.5 +/- 0.56 breaths/min and rectal temperatures by 0.6 +/- 0.02 degrees C compared with shade and fans alone in 2003. Cooling cows with evaporative tunnel ventilation reduced respiration rates by 13.1 +/- 0.78 breaths/min and rectal temperatures by 0.4 +/- 0.03 degrees C compared with fans and sprinklers in 2001. Thus, tunnel ventilation cooling dramatically reduced the exposure to heat stress and improved the comfort of lactating dairy cows when compared with traditional cooling technologies under the conditions present in the southeastern United States.

Heat stress has a dramatic impact on the dairy industry, reducing production and profitability throughout the southeastern United States. In many regions, management techniques can be used to mitigate the effects of heat stress, but available cooling technologies are often overwhelmed by the conditions of chronic heat stress present in southeastern United States. Although combining tunnel ventilation and evaporative cooling (evaporative tunnel cooling) seems to provide superior cooling for dairy cows, there is a dearth of reports on the impact of this technology on milk production. A model evaporative tunnel cooling facility in northern Mississippi was studied using 2 groups of 10 lactating Holstein cows housed in the tunnel barn and 2 groups of 10 matched herdmates housed in an adjacent naturally ventilated free-stall barn. Two 10-wk trials were performed in 2 yr beginning June 25, 2001, and May 26, 2003, in which cows housed outside were cooled by traditional fans and shade alone (2003) or with sprinklers (2001). In both years, the use of evaporative tunnel cooling decreased exposure to conditions of moderate heat stress by 84%. Cows cooled by evaporative tunnel ventilation increased feed intake by 12 and 11% over cows housed outside in 2001 and 2003, respectively. Evaporative tunnel cooling had no effect on milk composition, but increased milk yield over the 10-wk trial by 2.6 +/- 0.27 and 2.8 +/- 0.19 kg/cow per day in 2001 and 2003, respectively. In addition, somatic cell count was decreased 27 to 49% by evaporative tunnel cooling. Thus, under the range of environmental conditions present, evaporative tunnel cooling reliably reduced exposure to conditions of heat stress and improved milk production of lactating dairy cows during the summer season.

Consolidation and concentration in agriculture continue to be important topics. This paper uses a binomial probit model to assess the motivations for opportunities and participation in mergers, acquisitions, joint ventures, and strategic alliances in agricultural cooperatives. A Poisson model is also used to investigate the frequency of participation in these activities. Results show that competition, patronage refunds, research and development, and market diversification all affect opportunities and participation. Firm size, placement in the market channel, and research and development activities appear to influence the frequency of participation. [EconLit Categories: Q13, G34.] © 2002 Wiley Periodicals, Inc.

First, please permit me the latitude to use a bit of poetic license in coining the term, “ethanolization,” which attempts to describe the upheaval and chaos witnessed across the agricultural sector attributed to the booming corn-based ethanol industry. Ethanolization has focused its impact on agriculture and, in particular, the U.S. agricultural sector as a combination of market-induced and policy-induced factors have created a “perfect storm” that is causing dramatic shocks to virtually every crop and livestock producer and agribusiness. Coining the term ethanolization also borrows from past eras in agriculture described as the “mechanization” of agriculture in the 1940s and 1950s and the “industrialization” of agriculture in the 1990s. Mechanization described a period when widespread adoption of farm machinery occurred across the United States. Then, industrialization, accredited to a body of writings by Draben-stott and Barkema, portrayed a “quiet revolution” of ever-increasing size and specialization of U.S. farms, ranches, and agribusinesses. Now, ethanolization attempts to characterize a similar revolution that is affecting essentially every facet of American agriculture.