Browsing by Subject "Beef cattle"

Now showing 1 - 5 of 5
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    Backgrounding methods for growing beef cattle and strategies for incorporating alternative feedstuffs into diets of finishing beef cattle.
    (2011-05) Kelzer, Jolene Madonna
    Volatile commodity and cattle markets present challenges for profitable beef production. Four experiments were conducted to evaluate backgrounding methods for growing cattle and utilizing alternative feedstuffs in finishing diets to improve feedlot performance and efficiency. Experiment 1 evaluated the effectiveness of grazing stockpiled and swathed annual ryegrass as backgrounding systems on forage quality and beef stocker cattle performance. Results of experiment 1 suggest grazing stockpiled and swathed annual ryegrass may be viable backgrounding systems; however, forage maturity and winter weather conditions may reduce forage quality and accessibility to levels that can limit stocker cattle performance. Experiment 2 evaluated the effects of reproductive status (spayed vs. intact heifers supplemented with melengestrol acetate) and terminal implant strategy (moderate vs. aggressive) on beef feedlot heifer performance during backgrounding and finishing phases and on carcass characteristics. Results of experiment 2 suggest intact heifers supplemented with melengestrol acetate had greater performance during backgrounding; however, use of moderate or aggressive terminal implant strategies may allow similar performance during finishing and comparable carcass characteristics between spayed and intact beef feedlot heifers. Experiment 3 evaluated the effects of partially replacing dry-rolled corn in traditional corn-based finishing diets with either 35% conventional dried distillers grains plus solubles or 35% high protein dried distillers grains on beef steer feedlot performance and carcass characteristics. Results of experiment 3 suggest that although overall feed intake tended to be reduced, high protein dried distillers grains may successfully replace conventional dried distillers grains plus solubles or up to 35% of dry-rolled corn in finishing beef cattle diets. Experiment 4 evaluated effects of supplemental manganese in high-sulfur feedlot diets containing dried distillers grains plus solubles on in vitro and in vivo ruminal fermentation and hydrogen sulfide gas production. In vitro results of experiment 4 suggest that 1,000 ppm manganese in high-sulfur diets appeared to release less total hydrogen sulfide gas than 0 or 500 ppm manganese; whereas in vivo results suggest beef steers consuming 1,000 ppm manganese may have a less acidic ruminal environment prior to feeding to result in a tendency for reduced average ruminal hydrogen sulfide concentration.
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    Evaluating on-farm sampling strategies and corresponding gas emission estimation methods for livestock and poultry barns
    (2022-08) Soriano, Noelle Cielito
    The need for gas emission research is driven by multiple stakeholders to address avariety of concerns and priorities that stem from environmental, human, and animal impacts of gas emissions from barns. In this work, I first provide background on the mechanism of gas emission from these systems and an overview of emission estimation strategies in the literature. This is followed by a presentation of two thesis projects, which demonstrate outcomes and challenges related to different emission estimation strategies. In the first project, I investigate airflow patterns and estimate ammonia (NH3) and carbon dioxide (CO2) emissions using a multi-airspace model for a naturally ventilated deep-pit cattle barn, with discrete gas concentration data. The second project uses a mass balance approach to estimate volatile solids (VS) losses and NH3 emissions from a naturally ventilated poultry barn based on material flows in and out of a barn. Each estimation strategy is evaluated based on the practicality of the sampling approach in specific housing styles, and whether emission estimates are comparable to current emission estimation methods for each system. Findings from these two projects show that, ultimately, there will always be limitations to the various available emission estimation strategies, particularly related to in-barn sample collection. Understanding the appropriate application of each of these approaches is important when selecting an emission estimation approach that will allow researchers to obtain representative emission estimates from a variety of livestock and poultry systems.
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    Radio News Briefs for a Growing Minnesota, November 21, 1969
    (University of Minnesota, Agricultural Extension Service, 1969-11-21) University of Minnesota, Agricultural Extension Service