Understanding heat stress in beef cattle

Thermal stress is the result of a misbalance between heat produced or gained from the environment and the amount of heat lost to the environment. The level of thermal stress can range from minor or no effect to death of vulnerable animals. Under summertime conditions, thermal stress results in hyperthermia or heat stress. Heat stress in feedlot cattle is a common summertime occurrence in cattle-producing parts of the world (USA, Australia, Brazil, etc.). Effects on animals experiencing heat stress include decreases in feed intake, animal growth, and production efficiency. During these extreme events, animal losses can exceed 5% of all cattle on feed in a single feedlot. Luckily, these extreme events are generally very localized and last only a day or two. However, these losses can be devastating to individual producers within the affected area. The level of heat stress an individual animal will experience is a result of a combination of three distinct components: environmental conditions, individual animal susceptibility, and management of the herd. Environmental components include temperature, humidity, wind speed, and solar radiation. Several indices have been developed to summarize the different components into a single value. Individual animal susceptibility is influenced by many different factors including coat color, sex, temperament, previous health history, acclimation, and condition score. Finally, management greatly influences the effects of thermal stress. Management factors can be broken into four distinct categories: feed, water, environmental influences, and handling. Understanding these risk factors and how each one influences animal stress will aid in the development of management strategies and how to implement them. Management strategies that can be employed at the right time and to the correct groups of animals will increase benefits to the animals and limit costs for the producers

Students’ Knowledge of and Attitudes Toward Dairy Production: A Survey Methodology Report

This report presents findings from a pilot survey conducted among undergraduate and graduate students (N = 410) at the University of Nebraska-Lincoln about students’ perspectives on technology usage, consumption, and sustainability in dairy production systems. An interdisciplinary research team developed the survey instrument and report. The main purpose of this pilot study was to create and administer survey items to support further research on experiential education and outreach opportunities related to robotics in small-scale dairy production and rural economic development. Descriptive findings indicated that most students had some familiarity with dairy production and the nutritional aspects of dairy products but expressed a desire to learn more. The majority of participants agreed that “The sustainability of our food system is important to me personally.” Among three statements about technology usage in dairy production, the statement “technology will improve the livelihoods of people working in agriculture” received the highest mean score, indicating that students largely agreed with this statement. Regarding animal welfare, students believed that caretakers should ensure the health of dairy cows. Many indicated that they think small dairy farms can be financially viable. Notably, most students agreed with the statement “I enjoy learning through immersive experiences (hands-on or virtual reality).” Half of the students expressed a high or moderate level of interest in agricultural-related careers, 80 percent showed a high or moderate interest in technology-related careers, and 82 percent demonstrated a high or moderate interest in careers in sustainability

Heat and Moisture Production of Growing-Finishing Gilts as Affected by Environmental Temperature

Heat and moisture production (HMP) values are used to size ventilation fans in animal housing. The HMP values that are currently published in the ASABE standards were from data collected in the early 1950s. This study is one of a series of studies being conducted to update the HMP values for the ASABE and ASHRAE (American Society of Heating, Refrigeration, and Air Conditioning Engineers) Standards. This study focused on the HMP measurements on growing gilts in the weight range of 60 to 120 kg over a temperature range of 16 to 32°C. Thirty gilts selected on the basis of weight and health status were placed in one of five environmental chambers and in one of six pens in each chamber. Heat production rate (HP) was determined using indirect calorimetry methods after the animals were acclimated for 2 weeks to a particular temperature. Each measurement was made on an individual animal over a 21-hr period. It was determined that HP decreased, feed intake decreased, and moisture production (MP) increased as environmental temperature increased. HP was directly affected by the level of feed consumption. Dynamic measurements showed a diurnal HP pattern in that it was higher during light period than during dark period, with an immediate increase as the lights were turned on. Results on nursery age animals will be reported in a companion study

A Literature Review of Swine Heat Production

Current ASAE standards of heat and moisture production (HP, MP) for swine are primarily based on data collected nearly four decades ago. Feedstuffs, management practices, growth rate, and lean percentage of swine have changed HP and MP considerably in that time period. Literature data shows that lean percent increased 1.55% in the last 10 years, resulting in an increase in HP by approximately 15%. Data were compiled into two categories: prior to 1988, and 1988 to present. Analysis of this data revealed that HP increased 12.4% to 35.3% between the two categories, with the largest differences occurring at higher temperatures. The results also revealed lack of HP and MP data for greater than 90 kg pigs. The HP and MP standards for design of swine housing systems should be updated

Evaluating Ventilation Rates Based on New Heat and Moisture Production Data for Swine Production

Heat and moisture production (HMP) rates of animals are used for calculation of ventilation rate (VR) in animal housing. New swine HMP data revealed considerable differences from previously reported data. This project determined new design VRs and evaluated differences from previously recommended VRs. The swine production stages evaluated included gestation, farrowing, nursery, growing, and finishing. The ranges of ambient temperature and ambient relative humidity (RH) evaluated for VR were -25°C to 15°C in 10°C increments and 15% to 75% in 15% increments, respectively. Indoor set points for temperature and RH were, respectively, 15°C, 20°C, 25°C and 60%, 70%, 80% for all five ambient stages. The results showed that the old VR for moisture control was 54%, 30%, 69%, 31%, and 53% lower than the new VR for the gestation, farrowing, nursery, growing, and finishing stages, respectively. Updated recommendations for ventilation are necessary for designing and managing modern swine facilities

Design of University Small-Scale Dairy Processing Facility

This project was assigned to research the feasibility and value of implementing a dairy processing facility on the campus of the University of Nebraska-Lincoln. The facility would process milk produced from cows under the same roof and will serve as an educational experience for Nebraska dairy farmers, UNL students, and K-12 students in the Lincoln-Lancaster County area. If the project is successful and replicated across the state, this facility could have a significant impact on the reduction of milk transportation costs in the Nebraska dairy industry. The project began with researching milk processing methods and steps from production to consumption. Shortly after this step, information on milk consumption patterns was collected from UNL Dining Services to determine demand on campus. Every unit operation requires certain equipment to effectively ensure the safety and quality of the final product, and mass balances from UNL milk consumption data were used to size equipment and storage capacity. Engineering firms were then consulted to gather information on equipment specifications and prices. Equipment costs and operating costs (estimated with the help of Dr. Howell and other university dairy operations) were entered into a Monte Carlo simulation to analyze return on investment and a breakeven point. The results from the costs section showed that the fixed costs (equipment and engineering) for the milk processing would be about $1.2 million. The Monte Carlo simulation showed that the project would not turn a profit for 10-12 years, and approximately 2.25 million gallons of milk would need to be processed and sold to recover initial costs. Overall, the project successfully displays data that can be interpreted by the client to decide whether to move forward with the project and the appropriate scale for the project at UNL

Surface Application of Soybean Peroxidase and Calcium Peroxide for Reducing Odorous VOC Emissions from Swine Manure Slurry

A laboratory experiment was conducted to evaluate and compare surface-applied versus fully-mixed treatments of soybean peroxidase (SBP) plus calcium peroxide (CaO2) for reducing odorous volatile organic compound (VOC) emissions from swine manure slurry. Industrial-grade SBP (5-50 g L-1) and powdered CaO2 (0.16-1.6 g L-1) were applied to swine manure slurry in 7.6 L containers, and odorous VOC emission rates (phenolics, indolics, volatile fatty acids, methyl sulfides) were measured over a 14 d period using sorbent tubes and gas chromatography. The five treatments consisted of a control, the fully-mixed rate of 50 g L-1 SBP plus 1.6 g L-1 CaO2, and three surface-applied treatments of 10%, 50%, and 100% of the fully-mixed application rate. The odorants 4-methylphenol and skatole accounted for the majority of the odor activity value (OAV). The 10% surface-applied rate was as effective as the 100% surface-applied and fully-mixed application rates at reducing 4-methylphenol and skatole emissions for up to 10 d (P2 every 4-7 d. Future pilot- and field-scale research should focus on surface application of SBP and CaO2 at a rate equal to 10% of the fully-mixed rate

AGEN/BSEN 112 Final project: Moving and Temperament of Cattle

Cattle movement and weather may affect the body temperature of cows which in turn affects their natural behavior and can influence their metabolism. Cattle take several days to resume their normal eating patterns after being overheated, and that can affect dairy production. This project was assigned to study the effect of temperament (calm vs excitable) and evaporative cooling on the body temperature of moving animals to optimize the environmental conditions around the cattle and consequently, dairy production. The project began with processing of a data set from Dr. Tami Brown-Brandl who was the client/adviser for the group. The data contained the body temperature of six heifer cows recorded every minute for 24 hours. During the recording period the cows were moved around from their pen, and either had water sprayed on them to aid in their cooling, or left dry. The cows were classified by their temperament as calm or excitable, depending on their reaction to the presence of humans. The results from the analysis showed movement of cattle had a consistent effect on their average body temperature. As time went on during the movement process, all cattle saw an increase in body temperature with excitable cows reaching a higher maximum temperature than calm cows. Unaided cooling (dry treatment) was also affected by temperament of the cows. Calm heifer’s temperature dropped 0.1 °C about every 2 hours, while excitable heifer’s temperature dropped 0.1 °C about every 6 hours. Evaporative cooling or wet treatments help the heifers shorten excess periods of elevated body temperature with no notable difference due to temperament. Based on the analysis it is recommended to treat all heifers with a wet treatment after movement in an effort to keep heifers calm and therefore easier to corral and handle

Effects of Farrowing Stall Layout and Number of Heat Lamps on Sow and Piglet Production Performance

Most farrowing facilities in the United States use stalls and heat lamps to improve sow and piglet productivity. This study investigated these factors by comparing production outcomes for three different farrowing stall layouts (traditional, expanded creep area, expanded sow area) and use of one or two heat lamps. Data were collected on 427 sows and their litters over one year. Results showed no statistical differences due to experimental treatment for any of the production metrics recorded, excluding percent stillborn. Parity one sows had fewer piglets born alive (p \u3c 0.001), lower percent mortality (p = 0.001) and over-lay (p = 0.003), and a greater number of piglets weaned (p \u3c 0.001) with lower average daily weight gain (ADG) (p \u3c 0.001) and more uniform litters (p = 0.001) as compared to higher parity sows. Farrowing turn, associated with group/seasonal changes, had a significant impact on most of the production metrics measured. Number of piglets born influenced the percent stillborn (p \u3c 0.001). Adjusted litter size had a significant impact on percent mortality (p \u3c 0.001), percent over-lay (p \u3c 0.001), and number of piglets weaned (p \u3c 0.001). As the number of piglets weaned per litter increased, both piglet ADG and litter uniformity decreased (p \u3c 0.001). This information can be used to guide producers in farrowing facility design

Evaluating a New Shade for Feedlot Cattle Performance and Heat Stress

Heat stress in cattle results in decreased feed intake, lower daily gain, and potentially death in susceptible animals under intense conditions. A study was carried out during the summer of 2013 at the USDA-ARS U.S. Meat Animal Research Center feedlot evaluating the impact of shade on environmental conditions and cattle performance. A novel two-tiered shade was used in half of the 14 pens, each holding 30 animals. The shades were designed to reduce solar heat load by 40% to 60% and to provide traveling shade across the pen, providing varied amounts of shade area as well as varied solar reduction potential. The objective of this study was to determine if the shade was effective at improving performance (evaluated as average daily gain, feed intake, and feed to gain ratio) and reducing environmental conditions that cause heat stress. A group of mixed-breed cattle with varied genetics including both and were selected, penned on the basis of sex, and blocked by color. Production parameters of pen feed usage were measured daily, and individual body weights were taken monthly. Environmental conditions including air temperature, relative humidity, wind speed, ground temperature, and black globe temperature with and without shade were measured. Solar load on the pens was reduced when shade was provided, with both ground temperature and black globe temperature showing reductions. Cattle showed nominally better performance; however, no significant differences were found in gain or feed intake. Panting scores were significantly lower with shade provided; slopes of cattle respiration rate versus ambient temperature were significantly lower with shade during the afternoon period