Joseph P. Harner

Invited review: Sustainability of the US dairy industry.

The US dairy industry has realized tremendous improvements in efficiencies and milk production since the 1940s. During this time, farm and total cow numbers have decreased and average herd size has increased. This intensification, combined with the shift to a largely urban public, has resulted in increased scrutiny of the dairy industry by social and environmental movements and increased concern regarding the dairy industrys sustainability. In response to these concerns, a group of scientists specializing in animal welfare, nutrient management, greenhouse gas emissions, animal science, agronomy, agricultural engineering, microbiology, and economics undertook a critical review of the US dairy industry. Although the US dairy system was identified as having significant strengths, the consensus was that the current structure of the industry lacks the resilience to adapt to changing social and environmental landscapes. We identified several factors affecting the sustainability of the US dairy industry, including climate change, rapid scientific and technological innovation, globalization, integration of societal values, and multidisciplinary research initiatives. Specific challenges include the westward migration of milk production in the United States (which is at odds with projected reductions in precipitation and associated limitations in water availability for cattle and crops), and the growing divide between industry practices and public perceptions, resulting in less public trust. Addressing these issues will require improved alignment between industry practices and societal values, based upon leadership from within the industry and sustained engagement with other interested participants, including researchers, consumers, and the general public.

Effects of monensin on metabolic parameters, feeding behavior, and productivity of transition dairy cows

The effects of monensin on transition cow metabolism may be dependent on modulation of feeding behavior, rumen pH, and expression of key metabolic genes. Multiparous Holstein cows were used to determine the effects of monensin (400mg/cow daily) on these variables. Cows were randomly assigned, based on calving date, to control or monensin treatments (n = 16 per treatment) 21 d before their expected calving date, and cows remained on treatments through 21 d postpartum. Feeding behavior and water intake data were collected daily. Liver biopsies were conducted after assessing BCS and BW on d -21, -7, 1, 7, and 21 relative to calving for analysis of triglyceride (TG) content as well as mRNA abundance of cytosolic phosphoenolpyruvate carboxykinase, carnitine palmitoyltransferase 1a, and apolipoprotein B. Blood samples were collected 21, 7, and 4 d before expected calving and 1 (day of calving), 4, 7, 14, and 21 d postpartum for nonesterified fatty acid, β-hydroxybutyrate, glucose, insulin, and haptoglobin analyses. Ruminal pH was collected every 5 min on d 1 through 6 postpartum via a wireless indwelling probe. On d 7 postpartum, a caffeine clearance test was performed to assess liver function. Data were analyzed using mixed models with repeated measures over time. Monensin decreased mean plasma β-hydroxybutyrate (734 vs. 616 ± 41 μM) and peak concentrations (1,076 vs. 777 ± 70 μM on d 4 postpartum). Monensin also decreased time between meals prepartum (143 vs. 126 ± 5.0 min) and postpartum (88.8 vs. 81.4 ± 2.9 min), which was likely related to a smaller ruminal pH standard deviation in the first day after cows changed to a lactation ration (0.31 vs. 0.26 ± 0.015). Monensin also increased liver mRNA abundance of carnitine palmitoyltransferase 1a (0.10 vs. 0.15 ± 0.002 arbitrary units), which corresponded to a slower rate of liver TG accumulation from d -7 to +7 (412 vs. 128 ± 83 mg of TG/g of protein over this time period). No significant effects of monensin supplementation were observed on milk production, liver cytosolic phosphoenolpyruvate carboxykinase, apolipoprotein B, plasma nonesterified fatty acid, glucose, insulin, or haptoglobin. No effects on disease incidence were detected, but sample size was small for detecting such effects. Overall, results confirm that the effects of monensin on transition cows extend beyond altered propionate flux.

LABORATORY EVALUATION OF THE DUST-EMISSION POTENTIAL OF CATTLE FEEDLOT SURFACES

A laboratory apparatus was developed for measuring the dust-emission potential of cattle feedlot surfaces as affected by manure surface characteristics. A feedlot surface was simulated with a layer of dry, loose, sieved feedlot manure, either with or without a compacted soil layer underneath. The vertical action of the cattle hoof was reproduced by dropping a steel weight onto the manure surface. High-volume samplers for PM10 (particulate matter smaller than 10 .m aerodynamic equivalent diameter) were used to collect suspended PM10. The effects of kinetic energy of the falling weight, manure depth, manure moisture content, bulk density, and surface amendment (sawdust, wheat straw, and surface water application) were investigated. For each manure depth, PM10 emission was directly related to the kinetic energy of the falling weight. For each weight drop, PM10 emission did not differ significantly with manure depth. In addition, PM10 emission was inversely related to the manure moisture content. Compaction of the manure surface reduced PM10 emission. Increased amounts of water, sawdust, or wheat straw to the manure surface also significantly decreased PM10 emission in initial tests, but dislodging/displacement of wheat straw and penetration of the wetted surface crust by the falling weight increased the emission potential for subsequent tests. The weight drop test chamber developed is a simple and repeatable method that can be used to compare relative effectiveness of different dust abatement measures. While the measurements are reproducible, the vertical action of the cattle hoof is highly simplified; thus, the WDTC might not fully reproduce the actual vertical action of the cattle hoof on a feedlot surface. In addition, the resulting aerosol may not have similar physical characteristics as those of dust emitted from feedlots.

Relocation and expansion planning for dairy producers

Relocating or expanding a dairy facility requires a tremendous amount of time and planning. Owners or managers of dairies will go through a number of steps including: 1) developing a business plan; 2) choosing a design process; 3) developing specifications; 4) selecting location/site; 5) obtaining permits/legal; 6) obtaining bids; 7) selecting contractors; 8) buying cattle; 9) purchasing feeds; 10) financing; 11) managing construction; 12) hiring and training employees; 13) developing management protocols for the dairy; and 14) managing information flow. The dairy can be divided into these components: 1) milking parlor; 2) cow housing; 3) special needs facility (e.g., hospital, closeups); 4) replacement heifer housing; 5) manure management system; and 6) feed center. This article will focus on milking parlors, cow housing, grouping strategies, and site selection.

Effects of adjustable and stationary fans with misters on core body temperature and lying behavior of lactating dairy cows in a semiarid climate

Cows readily seek shade to reduce solar heat load during periods of high ambient temperature. Typically, auxiliary cooling systems are oriented to maximize cooling for shaded cows. However, when a shade structure is oriented north-south, stationary fan and mister cooling systems are unable to track shade as the suns angle shifts throughout the day, and thus can become ineffective. The FlipFan Dairy Cooling System (Schaefer Ventilation Equipment, Sauk Rapids, MN) employs fans and misters that follow shade and compensate for wind speed by rotating on a horizontal axis. Multiparous, lactating Holstein cows (n=144) on a commercial dairy in Arizona were cooled by a fixed system comprised of stationary fans and misters acting as control or the adjustable FlipFan operated for 16.5 h/d (0830 to 0100 h). Core body temperatures (CBT) of 64 cows (4 pens/treatment; 8 cows/pen; 6d) and lying behavior of 144 cows (4 pens/treatment; 18 cows/pen; 5d) were collected by intravaginal and leg data loggers, respectively. Cows were balanced by milk production, blocked by days in milk, and randomly assigned to pen within block. Pen was the experimental unit. In a second experiment, isothermal maps were developed using a fixed system of thermal data loggers arranged in the shaded areas of the pens at different times of day and were analyzed for differences in the temperature-humidity index (THI) achieved by each cooling treatment. Ambient conditions consisted of a mean temperature of 33.0°C, mean relative humidity of 40.3%, and mean THI of 80.2. Mean 24-h CBT for FlipFan was lower than control (38.9 vs. 39.1±0.04°C). A treatment × time interaction was observed in which CBT of FlipFan was 0.4°C lower than control from 0600 to 0800h and 1500 to 1600h. Cows cooled by FlipFan spent more time lying down compared with those cooled by control (9.5 vs. 8.6 h/d). Cows under FlipFan had more frequent lying bouts than did those under control (12.8 vs. 10.7 bouts/d). Lower CBT and decreased standing time are consistent with the findings of other studies when ambient heat load was reduced. In the second experiment, the FlipFan system achieved a lower THI in the morning and evening (5.9 and 1.7%, respectively), and the THI also tended to be 0.8% lower in the afternoon compared with that of control. Results indicate that FlipFan is more effective than a stationary fan and mister system at decreasing CBT, increasing lying time and bouts, and providing a more desirable microenvironment for cows throughout the day in a semiarid environment.

Composting Cattle Mortalities

Interest in composting cattle mortalities on-site is growing due to an increasing cost and reduction of rendering services and a desire of cattle operations to improve biosecurity precautions. Composting of cattle mortalities appears to be feasible if the composting operations are managed properly. The best management practices of cattle composting as learned from university demonstrations and extension visits of cattle operations are presented and discussed.

Particulate matter emission rates from beef cattle feedlots in Kansas—Reverse dispersion modeling

Open beef cattle feedlots emit various air pollutants, including particulate matter (PM) with equivalent aerodynamic diameter of 10 μm or less (PM10); however, limited research has quantified PM10 emission rates from feedlots. This research was conducted to determine emission rates of PM10 from large cattle feedlots in Kansas. Concentrations of PM10 at the downwind and upwind edges of two large cattle feedlots (KS1 and KS2) in Kansas were measured with tapered element oscillating microbalance (TEOM) PM10 monitors from January 2007 to December 2008. Weather conditions at the feedlots were also monitored. From measured PM10 concentrations and weather conditions, PM10 emission rates were determined using reverse modeling with the American Meteorological Society/U.S. Environmental Protection Agency Regulatory Model (AERMOD). The two feedlots differed significantly in median PM10 emission flux (1.60 g/m2-day for KS1 vs. 1.10 g/m2-day for KS2) but not in PM10 emission factor (27 kg/1000 head-day for KS1 and 30 kg/1000 head-day KS2). These emission factors were smaller than published U.S. Environmental Protection Agency (EPA) emission factor for cattle feedlots. Implications This work determined PM10 emission rates from two large commercial cattle feedlots in Kansas based on extended measurement period for PM10 concentrations and weather conditions, and reverse dispersion modeling, providing baseline information on emission rates for cattle feedlots in the Great Plains that could be used for improving emissions estimates. Within the day, PM emission rates were generally highest during the afternoon period; PM emission rates also increased during early evening hours. In addition, PM emission rates were highest during warm season and prolonged dry periods. Particulate control measures should target those periods with high emission rates.

FACTORS AFFECTING MILKING PARLOR EFFICIENCY AND OPERATOR WALKING DISTANCE

Milking parlor performance was evaluated in herringbone, parallel, automated side opening, and rotary milk parlors. The effects of entry time of the first cow, operator walking distance, pre-milking hygiene, and milking routine were determined. Operator walking distance is the highest in automated side opening parlors and lowest in rotary parlors. As the length of herringbone and parallel parlors increases, operator walking distances for double-10 parallel and Herringbone parlors ranged from 762 to 875m/h (2500-2871 ft/h) and double-40 parallel and herringbone parlors ranged from 991 to 1141 m/h (3251-3743 ft/h). Operator walking distance in parallel parlors is 95 to 150 m/h (312- 492 ft/h) less than herringbone parlors. Entrance time of the first cow increases with parlor length. Implementing a premilking hygiene routine increases labor requirements. Using a rotating milking routine will increase the number of cows milked per hour in larger parlors.

3-D and quasi-2-D discrete element modeling of grain commingling in a bucket elevator boot system

Unwanted grain commingling impedes new quality-based grain handling systems and has proven to be an expensive and time-consuming issue to study experimentally. Experimentally validated models may reduce the time and expense of studying grain commingling while providing additional insight into details of the particle flow. In this study, grain commingling in a pilot-scale bucket elevator boot was first modeled in three-dimensional (3-D) discrete element method (DEM) simulations. Experiments on the pilot-scale boot were performed using red-dyed and clear (uncolored) soybeans to validate the 3-D DEM model. Predicted results from the 3-D boot model generally followed the experimental data but tended to underpredict commingling early in the process. To reduce computational time, quasi-two-dimensional (quasi-2-D) DEM simulations were also evaluated. Comparison of predicted average commingling of five quasi-2-D boot models with reduced control volumes (i.e., with boot widths from four to seven times the mean particle diameter) led to the selection of the quasi-2-D model with a boot width of 5.6 times the mean particle diameter (i.e., 5.6d) to reduce computational time. In addition, the 3-D and quasi-2-D (5.6d) models were refined by accounting for the initial surge of particles at the beginning of each test and correcting for the effective dynamic gap between the bucket cups and the boot wall. The quasi-2-D (5.6d) models reduced simulation run time by approximately 70% compared to the 3-D model of the pilot-scale boot. Results of this study can be used to accurately predict commingling levels and improve grain handling, which can help farmers and grain handlers reduce costs and maintain grain purity during transport and export of grain.

PARTICULATE CONTROL EFFICIENCY OF A WATER SPRINKLER SYSTEM AT A BEEF CATTLE FEEDLOT IN KANSAS

Water sprinkler systems are one method for controlling particulate matter (PM) emissions from cattle feedlots; however, limited data are available on the efficiency of these systems. This research was conducted to determine the PM control efficiency of a water sprinkler system in a cattle feedlot in Kansas. Downwind and upwind PM10 concentrations at the feedlot (KS1) were monitored with tapered element oscillating microbalance (TEOM) PM10 monitors from January 2006 to July 2009. The feedlot was equipped with a sprinkler system with a maximum water application rate of 5.0 mm d-1 (5.0 L m-2 d-1). Control efficiency was determined by considering the PM10 data during sprinkler on/off events (i.e., the sprinkler system was operated for at least one day and was either followed or preceded by at least one day of no water sprinkling). Control efficiency equaled the percentage reduction in net PM10 concentration (i.e., downwind concentration - upwind concentration). PM10 control efficiency ranged from 32% to 80% with an overall mean of 53% (based on 24 h PM10 values). The effect of the sprinkler system in reducing net PM10 concentration lasted for one day or less. The PM10 concentration percentage reduction due to rainfall events was also determined at feedlot KS1 and at another feedlot (KS2). Feedlot KS2, located less than 40 km from KS1, was not equipped with a sprinkler system but practiced more frequent pen cleaning. Percentage reductions in net PM10 concentrations due to rainfall events were mostly in the range of 60% to almost 100% for both feedlots, with overall means of 77% for KS1 and 76% for KS2. The effects of rainfall events (with rainfall amounts >10 mm per event) lasted for 3 to 7 days depending on rainfall amount and intensity.