Sabina Angrecka

Influence of Wind on Air Movement in a Free-Stall Barn During the Summer Period / Wpływ wiatru na ruch powietrza w oborze wolnostanowiskowej w okresie letnim

Abstract Use of natural ventilation in the barn should lead to optimal microclimatic conditions over the entire space. In the summer, especially during hot weather, higher air velocity cools cows, which helps to avoid heat stress. The paper presents the results of studies on the evolution of air movement in a modernized free-stall barn of the Fermbet type with the natural ventilation system during the summer period. Based on measurements of velocity and direction of air flow (inside and outside the barn) and observations of smoke indicator, the movement of air masses in different parts of the barn was identified. Significant variations of air flow at different levels of the barn were found. These differences deviate from the accepted patterns of natural ventilation, which can be found in the literature. The range of a draught and stagnant air along with the conditions in which they are built was determined. On this basis, recommendations regarding the location of barns on the plots and the improvement of ventilation in summer were made. STRESZCZENIE Użytkowanie wentylacji naturalnej w oborze sprowadza się do osiągnięcia optymalnych warunków mikroklimatycznych na całej przestrzeni użytkowej hali. W lecie, zwłaszcza podczas upałów większa prędkość ruchu powietrza ochładza krowy i umożliwia uniknięcie zjawiska stresu cieplnego. W pracy przedstawiono wyniki badań nad kształtowaniem się ruchu powietrza w zmodernizowanej oborze wolnostanowiskowej typu „Fermbet” z systemem wentylacji naturalnej podczas lata. Na podstawie pomiarów prędkości i kierunku ruchu powietrza wewnątrz i na zewnątrz obory oraz obserwacji dymów wskaźnikowych dokonano rozpoznania przemieszczania się mas powietrza w poszczególnych jej częściach. Stwierdzono duże zróżnicowanie kształtowania się ruchu powietrza w różnych płaszczyznach obory odbiegające od przyjmowanych literaturowo schematów wentylacji naturalnej. Wyznaczono strefy występowania przeciągów, zastoisk powietrza oraz warunków podczas których powstały. Na tej podstawie sformułowano zalecenia dotyczące sytuowania obór na działkach oraz poprawy działania wentylacji w lecie.

Forecasting Heat Stress in Dairy Cattle in Selected Barn Zones with the Help of Thi and Thiadj Indexes / Prognozowanie Stresu Cieplnego U Bydła Mlecznego W Wybranych Strefach Obory Za Pomocą Wskaźników Thi I Thiadj

Abstract The paper presents the influence of temperature, relative air humidity, air movement velocity and solar radiation on forecasting the risk of heat stress in dairy cows in a free-stall barn during hot weather seasons. THI and adjusted THI indexes were calculated for the periods in which the air temperature exceeded 28°C in the barn, and when it reached 25°C. Based on the THI values obtained during the heat, which ranged from 63 to 83, the occurrence of heat stress in cattle was stated. Heat stress also caused a decrease in milk yield, from about 22 kg to about 18 kg in the technological group. The calculated THIadj values (83 to 90), taking into account the solar radiation and air movement velocity, indicated also the occurrence of health-threatening conditions for cattle. On the fourth day of heat the maximum daily value of THI in the first measurement point was 83 with THIadj of 90, while in the second point THI was 82 and THIadj was 87. This indicated the occurrence of significant differences in microclimatic conditions in the occupied zone of the same technological group. The influence of investigated microclimate factors on the formation of THIadj in the researched zone of the barn was stated. No proper method of its determination was also stated. The analysis of the impact of air movement velocity on THIadj value (P<0.05) and the solar radiation (P<0.05) demonstrated the importance of these parameters in forecasting heat stress in cows in the barn. Streszczenie Praca przedstawia wpływ prędkości ruchu powietrza oraz natężenia promieniowania słonecznego na prognozowanie ryzyka wystąpienia stresu cieplnego u krów w oborze wolnostanowiskowej. Wskaźniki THI oraz adjusted THI zostały obliczone dla okresów, w których temperatura powietrza w oborze przekraczała 28ºC oraz gdy dochodziła do 25ºC. W oparciu o uzyskane wartości wskaźnika THI podczas upału, wynoszące od 63 do 83, stwierdzono wystąpienie stresu cieplnego u bydła. Stres cieplny spowodował także spadek mleczności z około 22 kg do około 18 kg w grupie technologicznej. Obliczone wartości wskaźnika THIadj (od 83 do 90), uwzględniające natężenie promieniowania słonecznego i prędkość ruchu powietrza, wskazały również na wystąpienie warunków zagrażającychzdrowiu bydła. W czwartym dniu upałów maksymalny dobowy wskaźnik THI w pierwszym punkcie pomiarowym wynosił 83, THIadj 90, w punkcie drugim THI wynosiło 82, a THIadj 87. Wskazało to na występowanie znacznego zróżnicowania warunków mikroklimatycznych w obszarze przebywania tej samej grupy technologicznej. Stwierdzono wpływ analizowanych czynników mikroklimatu powietrza na kształtowanie się THIadj w badanym obszarze obory oraz brak właściwej metody jego określania. Analiza wpływu prędkości ruchu powietrza na wartość THIadj (P<0,05) oraz natężenie promieniowania słonecznego (P<0,05) wykazała istotność tych parametrów w prognozowaniu stresu cieplnego krów w oborze.

Impact of Barn Orientation on Insolation and Temperature of Stalls Surface

Abstract The aim of this study was to determine the effect of free-stall barn orientation relative to cardinal points on the insolation area and on the surface temperature of selected stalls in the summer period. The results of the experimental research were subjected to model analysis of the distribution of area of insolation into a barn. The studies showed that the surface of insolated stalls is heated to a temperature of 40°C, and in extreme cases up to 58°C. Taking into account the body temperature of cows (38–39°C), it can be concluded that the heat transfer from animals’ body to the environment, and thus the possibility of their cooling, were difficult. This is confirmed by observations of the behaviour of cows obtained from the video monitoring. Large differences were found in thermal conditions in the southern and northern stall areas, which in the midday hours were up to 10°C. The impact of clouds occurring during observations, included in the studies, contributed to the reduction of temperature of the stalls surface. During hot weather, short, ten-minute appearance of clouds, caused a decrease of the temperature of stalls surface by approx. 2.5°C. On this basis, it can be concluded that the use of shadings in building environment in the noon hours could limit the heating up of stalls and thus contribute to improving the living conditions of cows in barn.

Ammonia concentrations in a free-stall dairy barn

Abstract The 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.

Relationship between THI level and dairy cows’ behaviour during summer period

Abstract The presented study determining the relationship between the Temperature Humidity Index (THI) value during the summer months (June–August) and daily behaviour of 40 Holstein–Friesian dairy cows, including the length of standing, laying bouts and locomotor activity. Behaviour observations were conducted on a preferences test concerning their choice to time and place of rest with respect to time duration of THI: neutral (maximum 3 h with THI = 68), warm (time of THI > 68 occurrence lasted less than 12 h) and hot (time of THI > 68 occurrence lasted longer than 12 h). Obtained results was processed using analysis of the Spearman’s correlation coefficient with significant at p < .05. The results showed a decrease in daily total lying time between the neutral and hot periods from 9.9 to 7.8 h/d. Along with the increase in THI by 1 unit between the warm and hot periods, there was observed a decrease in total lying time by 38 min/d in the cubicles. With an increase in the THI was also observed an increase by 15 min/d in the lying cows in the manure alleys during the night-time. During the warm and hot periods, the cows’ activity showed a negative correlation with the increasing THI. Cows changed their behaviour during the summer depending on the prevailing environmental conditions. The behavioural studies on cows, without taking into account the variability of microclimate conditions, can lead to their inaccuracy and the misrepresentation of their results.

Effect of the duration of high air temperature on cow’s milking performance in moderate climate conditions

Abstract The main aim of the presented investigation was to determine the effect of the air thermal conditions variability on cow’s milking performance in summer in a moderate climate. The analyses covered the summer months of 2012-2013 (June-September) and shorter, several-day periods characterized by the times of elevated or high air temperatures and by the declines and increases in milking performance. The research was conducted in a free stall barn for Holstein-Friesian cows. The study showed that the thermoneutral temperature for high yielding cows decreases gradually with the registered increasingly warmer summer periods. The decreases in milk yield already commence at an air temperature equal to 20°C and also depend on the dairy cattle sensitivity. July and August, with a high number of hot days, caused that in September the cows responded faster to a worsening of thermal conditions and the decline in milking performance happened almost simultaneously with the air temperature change, at milking yield recovery after the period of 3-4 d (r=-0.84, P<0.04). The percent duration in the individual temperature ranges which caused a decrease of milk yield was also determined. In June, and at the beginning of July, this was 90% of the time with temperatures above 20°C, and simultaneously 45% above 25°C occurred to milking performance decrease (r=-0.89, P<0.02). In September, this was only 30% of the time with temperatures above 20°C (r=-0.91, P<0.01).

The Impact of Localization and Barn Type on Insolation of Sidewall Stalls During Summer

In the light of climate changes related to global warming forecasted by scientists, preventive measures against negative impact of solar radiation on dairy cattle welfare become vital. Apart from sprinklers and fans, different forms of shading, like native trees, extension of eaves or shade screens are increasingly often mentioned. The aim of the present studies was to determine the effect of barn type and orientation on the penetration of solar radiation into sidewall stalls during summer. A non-stationary analysis was performed for 3 types of curtain-sided freestall barns most commonly used in Poland, in which a model analysis of insolation was performed taking into account geographical location of Poland, azimuth and sun angles. The obtained results allowed us to identify optimal orientation of barns and to suggest the simplest technical measures to protect sidewall stalls from solar heat gain deleterious to cows. The model analysis of stall shading demonstrated that extension of barn eaves to 1 m on the southern side reduced the insolation of stalls over even up to 90% of their area.

Eligibility of Lying Boxes at Different THI Levels in a Freestall Barn

Abstract Cattle show a high sensitivity to changeability of microclimate conditions and heat stress that causes changes in the welfare and behaviour of cows. The presented study aimed at determining the relationship between the temperature humidity index (THI) value during the summer period and daily behaviour of dairy cows, including eligibility of lying boxes. All these aspects were measured under real production conditions. The investigated area, where microclimate conditions measurements were conducted, was a free-stall barn with single and double boxes, with manure and feeding alleys, housing 40 Holstein-Friesian cows. Observations were made on the behaviour of the cows based on a preference test concerning their choice of the best areas with respect to three ranges of THI values: neutral (N), warm (W) and hot (H). During the warm and hot period the research demonstrated a positive correlation between the level of THI and the share of standing cows (in period W - P<0.03 and H - P<0.008), and an inversely proportional one between the level of THI with participation of lying down cows (periods: W - P<0.06; H - P<0.004) and the length of their laying bouts in double boxes. The double boxes area was predominantly occupied, whereas single boxes area was the least often used. The occupation of manure alley areas was positively correlated with the level of THI.

Spatial and Temporal Distribution of Temperature, Relative Humidity and Air Velocity in a Parallel Milking Parlour During Summer Period

Abstract The research aimed at determining the most significant parameters affecting the microclimate of milking parlours, such as temperature, relative humidity and air movement in a parallel milking parlour in real operating conditions. The research was conducted in the summer period, when the risk of heat stress in cattle is higher. To check welfare of cows during milking, days with air temperature >25°C and days with temperature equal or lower than 25°C were analysed. Observation and analysis were performed for air flow in milking parlour, range of supplied air stream and how air movement affects cattle. It was observed that the irregular distribution of air movement led to the development of diverse air velocity in different zones of the milking parlour (0.2-9.0 m∙s-1). As a consequence, the conditions inside the barn were not homogenous for all the cattle. A significant effect of the cows and external air temperature (which depends indirectly on orientation of the milking parlour relative to cardinal directions) on temperature increase (approx 6°C) was concluded, with relative air humidity at the level of 85-90%, during the milking, which led to systematic decrease of microclimatic comfort for cattle. Based on the conducted research, it was concluded that the design of ventilation systems in parallel milking parlours should be preceded by increased research not only on ventilation system efficiency but also on the distribution of flow ventilated air.

The impact of barriers inside a herringbone milking parlour on efficiency of the ventilation system.

Abstract The research aimed at establishing the pattern of air movement inside a 2×10 herringbone milking parlour equipped with supply mechanical ventilation. Observations and analyses were made for the streams of air supplied to the parlour, their movement pattern and spread range. Also, temperature and relative air humidity after and before evening milking routine were measured. It has been concluded that barriers installed inside the milking parlour play a significant role in creating unfavourable microclimatic conditions during milking, particularly for the last group of cows. The study points out possible threats to animal welfare and operator’s working conditions. Based on the conducted experiments, the paper defines recommendations for proper design of ventilation systems inside herringbone milking parlours. Streszczenie Celem pracy było zbadanie rozkładu ruchu powietrza w hali udojowej typu „rybia ość” 2×10 z wentylacją mechaniczną nawiewną. Obserwacjom i analizie poddane zostało kształtowanie się strug powietrza nawiewanego do hali i ich zasięg. Określono również temperaturę i wilgotność względną powietrza przed i po doju wieczornym. Stwierdzono bardzo duży wpływ elementów wygrodzeń hali udojowej na tworzenie niekorzystnych warunków mikroklimatycznych w trakcie doju, zwłaszcza dla ostatniej grupy krów. Wskazane zostały zagrożenia dla dobrostanu zwierząt podczas doju oraz komfortu pracy dojarza. Na podstawie przeprowadzonych badań określono zalecenia dotyczące projektowania systemów wentylacyjnych w halach udojowych typu „rybia ość”.