Freestall Dairy Barns Research Articles

Ammonia concentrations in a free-stall dairy barn

AbstractThe paper presents the results of research on indoor ammonia (NH3) concentrations in the air in a free-stall barn. The differences in measurement results mainly depended on the season and weather conditions. The study also showed a significant correlation (P<0.01) between the NH3 concentration and temperature, relative humidity and air movement velocity inside the barn. The lowest NH3 concentration was recorded in the summer (0.0 ppm) in the presence of high air temperatures, low humidity and increased exchange of ventilated air. In winter during severe frosts, highest ammonia concentration (8.0 ppm) was noted, caused by limited ventilation. The highest daily ammonia concentration was usually recorded during the night. This was due to increased relative air humidity and low air velocities. It was concluded that the average level of ammonia of 2.73 ppm during the entire year was significantly below values defined as harmful for animals and people.

A direct method of measuring gaseous emissions from naturally ventilated dairy barns

Air pollutant emission rates from mechanically ventilated (MV) dairy barns are determined from the product of the differences in concentrations of pollutants in air at the inlet and exhaust points and the corresponding ventilation rates. In contrast to well defined entry and exit points in MV barns, large area air inlets or outlets characterize naturally ventilated (NV) freestall dairy barns. Complicating this scenario even more, pertinent airflow characteristics (velocity and direction) necessary for determining ventilation rates vary continuously, both temporally and spatially. This paper describes implementation of a direct method, generally equivalent to the approach used for MV barns, for determining air emission rates of NV barns. Ultrasonic anemometers (sonics) located at salient points in the barn openings mapped air inflow and outflow velocities necessary to calculate ventilation rates. Pollutant concentrations in the air entering or leaving the barn during a given period were measured at sampling points located next to the anemometers. The air inflow rates were, in general, higher than the air outflow rates from the barns, but diurnal profiles were similar. The observed ventilation characteristics were consistent with prevailing wind directions. Air inflows were observed predominantly at windward openings of the barn, while the outflows were mainly at the barn's leeward openings. Results indicated that either: (i) the average of the air inflow and outflow rates (averaging approach), or (ii) the air inflow rates (inflow-only approach) were credible representations of ventilation rates. Results also revealed use of an on-site weather station and one sonic mounted in the middle of each wall of the barn as a possible approach for determining barn ventilation rates. The suggested use of ventilation rates for interpolating missing concentrations from intermittent gas measurements could potentially increase the integrity of emission rates at significantly lower capital investment and operational costs.

Fan cooling of the resting area in a free stalls dairy barn

This summer study evaluated the effect of providing additional fans (cooling) in the resting area within a free-stall dairy barn that had fans and sprinklers in the feeding area and paddock availability. Thirty cows were divided into two homogenous groups and kept in two pens: one had the resting area equipped with two fans (FAN) while no fans were added to the other resting area (CON). Microclimatic parameters, rectal temperature (RT), breathing rate (BR), milk yield, and milk pH traits were recorded. Time budgeting and the behaviour of the cows (time spent in the feeding area, standing and lying in other areas) were also recorded using digital video technology. Two slight-to-moderate heat waves were observed. During the hottest period the daily maximum temperature recorded was 33.5 °C and the daily maximum THI was 81.6. During this period, the BR and RT increased only slightly in both groups, with lower BR (n.s.) in FAN compared with CON. Milk yield was better maintained (n.s.) in FAN compared with CON during the hottest period. The FAN cows showed a greater (P<0.05) lying time in the free stalls (9.5 and 8.6 h/day in FAN and CON, respectively), whereas CON cows made greater (P<0.05) use of the paddock during evening and late evening hours. Consequently, the total daily lying time was 13.5 h/day in both groups. In conclusion, the results suggest that using fans in the resting area improves cow comfort, which increases use of the resting area. The lying time results also suggest that the benefits of providing ventilation in the resting area might be more evident in barns where there is no paddock.

Particulate matter dynamics in naturally ventilated freestall dairy barns

Particulate matter (PM) concentrations and ventilation rates, in two naturally ventilated freestall dairy barns, were continuously monitored for two years. The first barn (B1) housed 400 fresh lactating cows, while the second barn (B2) housed 835 non-fresh lactating cows and 15 bulls. The relationships between PM concentrations and accepted governing parameters (environmental conditions and cattle activity) were examined. In comparison with other seasons, PM concentrations were lowest in winter. Total suspended particulate (TSP) concentrations in spring and autumn were relatively higher than those in summer. Overall: the concentrations in the barns and ambient air, for all the PM categories (PM2.5, PM10, and TSP), exhibited non-normal positively skewed distributions, which tended to overestimate mean or average concentrations. Only concentrations of PM2.5 and PM10 increased with ambient air temperature (R2 = 0.60–0.82), whereas only concentrations of TSP increased with cattle activity. The mean respective emission rates of PM2.5, PM10, and TSP for the two barns ranged between 1.6–4.0, 11.9–15.0, and 48.7–52.5 g d−1 cow−1, indicating similar emissions from the two barns.

Layouts for small freestall dairy barns: Effect on milk yield for cows in different parities

Freestall housing for dairy cows has many different layouts and the space allocated for cows differs considerably. The objective of the present study was to investigate possible associations between barn layout and milk yield for different parities in small dairy freestall barns. Layouts of 204 Norwegian freestall barns constructed during the period from 1995 to 2005, and with a mean herd size of 42.7±15.5 cows, were obtained and merged with milk yield data and calving interval, for each parity, from the Norwegian Milk Recording System (NDHRS). The milk yield data set contained 20,221 different lactations from these 204 herds. Both simple mixed models, including the different explanatory variables one by one together with parity, calving interval, and herd as random effect, and a final mixed model, including all significant explanatory variables, were created. According to variables tested in this study, the final mixed model estimates show that only primiparous cows benefit significantly from increased free space allocation. Milk yield was generally higher in automatic milking system barns compared with that in barns with milking parlors, but not for primiparous cows. Milk yield was higher for all parities for barns using separation pens in accordance with the recommendations. Barns with 2 or more dead-end alleys had lower milk yield compared with that from layouts without dead-end alleys. Primiparous cows benefited from water troughs located for easy access and responded with increased milk yield. In 10% of the barns, the water trough capacity was less than 47% of the recommendations, and all parities benefited from a water trough capacity higher than this level. Higher parities had increased milk yield when water trough capacity was more than 80%. Feed bunk space, number of freestall rows, and the location of freestalls had no significant effect on the milk yield. The present study showed that increased space and improved access to water is beneficial to primiparous cows, whereas layouts without dead-end alleys and improved water capacity is beneficial for all cows in freestall systems.

Effect of dietary crude protein on ammonia-N emission measured by herd nitrogen mass balance in a freestall dairy barn managed under farm-like conditions

The main objective of this experiment was to monitor the impact of barn side and dietary crude protein (CP) on production performance, manure production and composition, and ammonia nitrogen (N) emission from a lactating dairy herd housed in a free-stall barn and managed under farm-like conditions throughout a number of months in each season of the year. The 78-cow lactating herd of the University of Wisconsin-Platteville (USA) was halved and each group was allocated to either the north or south side of the barn and either a recommended (REC) diet with 16.7 ± 1.3% CP dry matter basis (DM) or an excess (EXC) CP diet containing 1.5 units of CP above the REC diet (18.2 ± 1.5%). In 7 months between February 2004 and January 2005, total manure collection was conducted by manual scraping of the alleys and ammonia-N emission was calculated as intake N + bedding N – milk N – scraped manure N. Side of the barn (northern v. southern exposure) did not influence measurements and there was no effect of dietary CP on dry matter intake (DMI), milk, milk fat, and milk protein production, but a lower manure N concentration was observed for the group of cows fed the REC diet compared with the EXC diet (3.43% v. 3.66% of DM). Nitrogen intake was 63 g/day lower (643 v. 706 g/day), milk N was unaffected (157 g/day), manure N was 32 g/day lower (391 v. 423 g/day), and ammonia-N emission was 34 g/day lower (93 v. 127 g/day) for the group consuming the REC diet compared with the group consuming the EXC diet. There were larger variations in measured responses among months of the year than between level of dietary CP. Wet and dry manure excretions tended to be higher, but manure pH was reduced when corn silage became unavailable and the diet included additional corn grain and alfalfa silage as the only forage source. Prediction of manure N excretion for a group of cow determined as N intake – N milk was 9% higher than current prediction equations of the American Society of Agricultural Engineers. Ammonia-N loss averaged 110 g/day per lactating cow, but ranged from 64 g/day to 178 g/day with no clear seasonal pattern. There was no clear association between barn temperature, manure temperature or manure pH and ammonia-N emission; however, intake N explained 61% of the variation in ammonia-N emission.

Layouts and Space Allocation in Norwegian Freestall Dairy Barns

The objectives of this article are to describe layouts and space allocation within Norwegian freestall dairy barns. Layouts from 207 Norwegian freestall barns, 94 new and 113 rebuilt, constructed during 1995-2005, and with a mean of 42.0 ±16.5 freestalls for lactating cows, were obtained and the areas dedicated for milking cows were analyzed. The mean total cow area (TCA) was 8.37 ± 1.09 m2 per freestall, ranged from 5.88 to 12.61 m2, decreased with increased number of stalls, and was higher for new buildings compared to rebuilt buildings. The mean freestall area was 2.78 ± 0.18 m2 per freestall and represented 33.2% of the TCA. Both alley area and feed bunk space decreased with increasing number of freestall rows. The mean alley area was 3.70 ± 0.63 m2 per freestall and represented 44.2% of the TCA. Widths of feed alleys (3.21 ± 0.43 m) and freestall alleys (2.25 ± 0.44 m) varied considerably, and a high proportion was below the American recommendations. However, only a minor proportion was below the international recommendations. Barns with automatic milking systems (AMS) had approximately 1.0 m2 less milking area per freestall compared to barns with milking parlors. Nearly 25% of the barns had no separation area for maternity and sick cows, and even 16% of new barns had no space for this important group of cows. Increased herd size and choosing AMS over traditional parlors were structural factors that reduced building space. However, in several barns, space was minimized by decreasing the alley widths and skipping the separation area, which is absolutely not recommendable.

Effects of Reducing Dietary Nitrogen on Ammonia Emissions from Manure on the Floor of a Naturally Ventilated Free Stall Dairy Barn at Low (0–20°C) Temperatures

This study was conducted to determine the potential for reducing ammonia (NH3) emissions from manure deposited on the floor of a naturally ventilated free stall barn by mid-lactation dairy cows fed reduced or normal N diets. Two crude protein (CP) diets (178 g kg(-1) [high] and 159 g kg(-1) [low] dry matter ), were used. The diets were fed to 48 Holstein cows in a replicated crossover design with two pens per diet. The NH3 emitted from the manure deposited on the floor was measured using a dynamic flux chamber. The NH3 emissions were 2.7 (+/-2.0) and 2.9 (+/-1.8) g N cow(-1) d(-1) for high and low CP diets, respectively. Ammonia emission rates were significantly affected by manure pH, TKN, and ambient air temperature (P<0.05). Dietary CP affected the feed N intake (8.7 and 7.1 kg pen(-1) d(-1) for high and low CP, respectively), but did not affect milk yield (500 and 489 kg pen(-1) d(-1) for high and low CP, respectively) and milk CP content (30 g kg(-1) for both the high and low CP diets). The N utilization efficiency was 29.0% and 32.7% for the high and low CP diets, respectively. Reducing dietary CP reduced total Kjeldahl N (TKN) in manure, but did not affect the total ammoniacal N (TAN) in manure and had no significant effect on the ammonia emission rates from the barn floor.

Relationship between layout and timber structures in freestall dairy cattle barns: Influence of internal features

The features, dimensions and organisation of internal elements in freestall dairy barns are decisive in determining the layout design. The aim of this study was to define structural solutions using timber elements for the most common barn layouts. The objectives were to simplify the structural concept of the building to develop standardised construction techniques. This involved a study of the organisation and dimensions of layout elements and their relationship with the building structure, the definition of a structural bay adapted to the layout and to the materials used, the definition of the structural solutions using unit modules, and the calculation of the sections of structural members. This methodology provided structural solutions for most of the common layout designs with unit modules that could be adapted to internal elements. These solutions included two reference values for structural bays, 3.75 and 5.00 m wide, associated with primary framing with rigid joint simple members, and primary framing with lattice beams or roof trusses and columns. An important level of uniformity was developed in the preliminary study of the structural members. The member that was most sensitive to variations in the strength of timber was the purlin, where a standard solution was less effective. The importance of adjusting the internal elements and using suitable dimensions for the structure in the design process is stressed.

Cooling Effectiveness of High-Volume Low-Speed Fans Versus Conventional Fans in a Free-Stall Dairy Barn in Hot, Humid Conditions

High-volume low-speed (HVLS) fans use less energy and are quieter than conventional high-speed fans; however, data on the cooling effectiveness of these fans in a dairy free-stall barn in a hot, humid climate is limited. A 4-row free-stall dairy barn located in Tifton, Georgia was fitted with 2 redundant mechanical cooling systems. The first system utilized 0.9-m diameter high-speed cooling fans installed over the feeding area and over the free stalls 6m apart (conventional system). Each fan was equipped with 4 high-pressure mister nozzles. The second system utilized 7.3-m diameter HVLS fans installed over the center drive-through aisle at 18-m spacing (HVLS system). Evaporative cooling was provided with the same nozzles used in the conventional system. Misters were automatically turned on for both systems when relative humidity was below 85% and temperature was above 24°C. Two groups of 64 cows each were cooled randomly by one system or the other during 2 tests conducted in 2004 and 2005. Four cows within each group were fitted with vaginal temperature probes to monitor the deep body temperature every 5min on 4 consecutive d. Temperature and relative humidity inside the barn were also recorded every 5min. Air speeds in the barn were measured with each system operating separately. Observed air speeds were lower for the HVLS system (0 to 8.1 km/h) than for the conventional system (0 to 13 km/h), although air speed was more evenly distributed with the HVLS system. Body temperature was 0.2°C higher (P < 0.01) with HVLS fans compared with the conventional system. These results indicate that the HVLS fans were less effective at cooling cows than the conventional system under extremely hot, humid conditions.

Drinking water requirements for lactating dairy cows (2001)

A study to determine the amount and location of water consumption in dairy freestall barns located in northeastern Kansas was conducted during the summer of 2000. Three farms, two Holstein farms with either 2-row or 4-row freestall barns and one Jersey farm with 4-row freestall buildings, were used. Summer water usage averaged 30 to 40 gallons per Holstein cow/day and 20 to 40 gallons/cow/day for Jersey cows depending on age and stage of lactation. The farms with Holstein cows had a water usage ratio of 4 to 4.5 lb of water per lb of milk produced and Jersey cows required 3.1 lb of water per lb of milk production. However, at the Holstein dairies, only about 85% of this water was consumed and the other 15% was utilized to refill the tanks after tipping twice daily to clean cross-overs and water troughs. In addition, 35 to 45% of the water consumed is from a water station in the center crossover of each pen. Cattle also drank the least amount of water from the trough located in the crossover furthest from the pen entrance. When given access to a water trough on the milking parlor exit, cattle consumed 10% (3.5 gallons/cow/day) of the daily water intake at this location. Water usage for drinking increased as milk production increased. Adequate water system capacity and water rights are needed to make allowances for future increases in milk production. Water consumption was greater at the center alleys. Therefore, engineers should consider additional space and/or water troughs at these watering stations. (

Losses of manurial nitrogen in free-stall barns

The objectives of this study were to measure nitrogen losses from dairy manure in free-stall dairy barns which were scraped once a day and to compare these results with a previously published model predicting nitrogen losses in the barn. From two farms floor samples were collected once a week from manure just scraped from each alley. The results of this sampling programme indicated that nitrogen losses were minimal when the average daily air temperature in the barn was below 5°C. Between 5°C and 25°C the losses increased with temperature, reaching 40% to 60% of the total nitrogen in the manure. The measured losses were similar to the model's predictions below 10°C but were greater than the predicted values at higher temperatures. Since the model considered only urea and ammonia nitrogen as available for loss, it is apparent from the farm data that under warm conditions significant quantities of non-urea organic nitrogen in both the urine and faeces are ammonified within 24 h.

TECHNICAL ASPECTS OF LIQUID COMPOSTING

As a consequence of stiffening legislation for environmental control, livestock producers are coming to realize that how they handle manure removal, drainage, and odor control (or lack thereof) is no longer their decision alone. While providing a solution to an immediate problem of odor control, the dairy farmer is beginning to become aware that in the future he may be required to produce an effluent which could be discharged to the nearest stream or lake. The De Laval Separator Company has developed a liquid composting system for deodorizing, pasteurizing, biologically decomposing, and chemically purifying dairy cow waste. The theory of liquid composting is discussed and several modes of LICOM™ System operation are described. Particular emphasis is placed on a description of a completely automated manure handling and treatment system operating at an 80-cow, free-stall dairy barn. Data covering 24 months of operation are presented.