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Physical Sciences and Mathematics Commons

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Full-Text Articles in Physical Sciences and Mathematics

Integrating Herbivore Population Dynamics Into A Global Land Biosphere Model: Plugging Animals Into The Earth System, Shree R. S. Dangal, Hanqin Tian, Chaoqun Lu, Wei Ren, Shufen Pan, Jia Yang, Nicola Di Cosmo, Amy Hessl Dec 2017

Integrating Herbivore Population Dynamics Into A Global Land Biosphere Model: Plugging Animals Into The Earth System, Shree R. S. Dangal, Hanqin Tian, Chaoqun Lu, Wei Ren, Shufen Pan, Jia Yang, Nicola Di Cosmo, Amy Hessl

Plant and Soil Sciences Faculty Publications

Mammalian herbivores are an essential component of grassland and savanna ecosystems, and with feedbacks to the climate system. To date, the response and feedbacks of mammalian herbivores to changes in both abiotic and biotic factors are poorly quantified and not adequately represented in the current global land surface modeling framework. In this study, we coupled herbivore population dynamics in a global land model (the Dynamic Land Ecosystem Model, DLEM 3.0) to simulate populations of horses, cattle, sheep, and goats, and their responses to changes in multiple environmental factors at the site level across different continents during 1980–2010. Simulated results show …


Selection Of Breeding Stock By U.S. Meat Goat Producers, Narayan Nyaupane, Jeffrey Gillespie, Kenneth Mcmillin, Robert Harrison, Isaac Stienei Aug 2017

Selection Of Breeding Stock By U.S. Meat Goat Producers, Narayan Nyaupane, Jeffrey Gillespie, Kenneth Mcmillin, Robert Harrison, Isaac Stienei

Community & Leadership Development Faculty Publications

Using nationwide survey data, we investigate U.S. meat goat producer preferences and willingness to pay for meat goat breeding stock attributes. Discrete choice experiments were employed, and mixed logit and latent class models were used for analysis. Results showed that producers preferred animals that were highly masculine/feminine, had good structure and soundness, and were of the Boer breed, whereas they preferred fewer animals that were older, of Kiko and Spanish breeds, and priced higher. Significant preference heterogeneity was found among the respondents. Larger-scale producers had greater preference for high masculinity/femininity, good structure and soundness, and Boer bucks.


Ammonia And Carbon Dioxide Emissions Of Three Laying-Hen Housing Systems As Affected By Manure Accumulation Time, Timothy A. Shepherd, Hongwei Xin, John P. Stinn, Morgan D. Hayes, Yang Zhao, Hong Li Jan 2017

Ammonia And Carbon Dioxide Emissions Of Three Laying-Hen Housing Systems As Affected By Manure Accumulation Time, Timothy A. Shepherd, Hongwei Xin, John P. Stinn, Morgan D. Hayes, Yang Zhao, Hong Li

Biosystems and Agricultural Engineering Faculty Publications

Laying-hen housing design and management are the most significant factors affecting the generation and release of gaseous ammonia to the atmosphere. Transitioning the hen housing type from traditional high-rise (where manure is stored within the house for about one year) to modern manure-belt style (where manure is removed every 1 to 4 d and placed into long-term storage) has significantly improved in-barn air quality and reduced farm-level ammonia emissions. As a direct result of the advantages, 100% of new construction for U.S. egg production incorporates manure-belt systems that regularly remove manure from the houses. However, manure-belt system designs (e.g., active …