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Recent studies suggest the importance of hair coat in cattle adaptation to heat stress environments. The objective of this study was to quantify the physiological responses of Holstein cows to two different loads of solar radiation (lo-550W/m2 and hi-880W/m2). These solar loads represent the am (1000-1200) and pm (1300-1600) periods in Arizona summers. Cows (dry and pregnant) of two hair coats: a) black (n=4, >90% black) and b) white (n=3, >90% white; n=1, 60% white) were used in a switched back design in an environmental chamber study with or without solar radiation. Each exposure to solar radiation consisted of 3 days with 2 white and 2 black cows. Daytime THI for the chambers were set at 84 (38.9°C, 25% RH) and nite time THI were set at 70 (23.3°C, 56% RH). Physiological responses measured were: a) respiration rates, b) dorsal skin temperations, c) rectal temperatures and d) sweating rates. Black hair coat absorbed 91% of the solar load while white hair coat absorbed 57%. Dorsal temperatures for black or white coat at lo solar were 39.5°C and 34.5°C and at hi solar were 41.7°C and 34.9°C, respectively. Respiration rates were not different for the coat colors; lo solar 86 breaths/min. and hi solar 99 breaths/min. Rectal temperatures at lo solar were 38.9°C for black and 38.7°C for white and at hi solar were 39.4°C for black and 39.0°C for white. Cows with black hair coat had 1.5x higher sweating rates than cows with white hair coat at both solar loads. Variations in the ability to thermal regulate by sweating within a hair coat color were observed. The study suggested that cows with black coat absorbed higher solar load and this was compensated by higher sweating rates facilitated by higher dorsal skin temperatures thus allowing for greater evaporative cooling. [ABSTRACT FROM AUTHOR]

The tentative agreement between the US Environmental Protection Agency and the US Dept. of Agriculture for Animal Feeding Operations (AFOs) and Confined Animal Feeding Operations (CAFOs) imposed stringent regulations across geographic regions irrespective of climate. Hawai'i's sub-tropical/tropical climate has a year round growing season for all major agriculture disctricts. As an island state, she is further impacted by Clean Water Act, Coastal Zone Management Act, etc. Her isolation and cultural heritage make livestock operations important within the economic components. Hence, a multidisciplinary approach is needed for developing alternative measures to alleviate potential risks in violating the AFOs/CAFOs rules. The steps were: i) identify the potential problems, ii) develop an outreach/education program for the producers, iii) solicite the participation of colleagues with different skills and expertise, iv) implement the project and v) evaluate the outcome. Results of these efforts led to: a) paricipation/commitment of producers "in-kind" match; b) successful grants for education and implementation of project; c) a field trial on 4 species of tropical forages and 2 sub-surface irrigation was established on producer's site; d) data collected include plant tissue analyses, soil nutrients, percolation rate of affluent, nutrient uptake by forages and e) new expanded project to resolve wastewater management in dairies. The study showed that Bana grass (Pennisetum purpureum) could yield ~60 tons DM/ha/yr, with high nutrient uptake of N (>500kg/ha/yr) and P (100-300kg/ha/yr) without leaching or accumulation of such nutrients in the root zone. The elements contributing to the success of this project were: 1) commitment and follow through from all parties and 2) constant communication between parties. A multidisciplinary approach brought different skills and expertise to solve problems by further expanding the knowledge and awareness critical issues. The program yielded data that were successfully used to obtain USDA/EQIP grant for nutrient management in operations with limited land area. [ABSTRACT FROM AUTHOR]