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Elzbieta Bombik1, Antoni Bombik2, Krystyna Tyszuk2 ©
1 Department of Reproduction and Animal Hygiene, 2 Department of Agricultural Experimentation, University of Podlasie, Siedlce, Poland
RELATION BETWEEN AIR THERMAL AND HUMIDITY CONDITIONS IN PIGGERY BUILDINGS AND EXTERNAL CLIMATE
The work compares selected parameters of microclimate in five piggeries throughout the autumn-winter period. In addition, relations between the external climate and air temperature and relative humidity inside the buildings were determined.
Key words: piggery, air temperature, air relative humidity, external climate
Introduction. The rearing environment has got a pronounced effect on animal performance and quality of products obtained from the animals. Under a given feeding regime, optimum production is obtained when microclimate indicators remain within the limits that do not stimulate the organism to produce reaction to them. Each factor, when outside the optimal limits, shows stress-stimulating effect. Negative impacts of these factors, when summed up, result in the so-called environmental resistance which limits the volume of animal production.
Feeding and technological factors are the most important elements of the rearing environment. The latter include thermal and humidity factors which are conditioned by the livestock buildings and their facilities, as well as the animals housed in them (Cena, 1980; Myczko, 1999; Walczak, 2006).
Deviations of each microclimatic factor from zootechnical norms, in particular temperature and air humidity, have an influence on animal behaviour and meat quality (Fraqueza et al., 1998; Huynh et al., 2005). The livestock building should be designed so that changes in the external climate do not result in exceeding of building microclimate optimal norms. At the same time, the building ought to function under technological conditions (Bombik and Kolbuszewski, 1995; Walczak, 2006).
The objective of the present work was to compare microclimates in selected piggeries in the autumn-winter period, and to determine the degree of dependence between the external climate and air physical parameters (temperature and relative humidity) inside the buildings.
Material and Methods. Studies were conducted in 5 piggeries (A, B, C, D, E) in the Mazovia region. The piggeries were characterized by similar technical and technological solutions and similar stocking density of animals. They were specialist, detached buildings which were relatively new as they had been under use for 7 to 10 years. Bricks and hollow tiles were used for their construction, the walls were plastered on both sides, the ceiling was concrete with a functional attic. The animals were kept on shallow bedding, the sewage system worked efficiently. Ventilation
© Elzbieta Bombik, Antoni Bombik, Krystyna Tyszuk, 2008
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facilities were based on air ducts blowing off the air whereas fresh air entered the buildings through slightly open doors and windows. One-pane glass windows with wooden frames were situated in longer walls. Depending on the building, the ratio of window pane area and floor area ranged from 1:20 to 1:30.
Measurements of air physical parameters, that is temperature and relative humidity, were taken in autumn and winter, based on methodological assumptions developed by Janowski (1979), Dobrzanski and Kolacz (1996) and Kosla (2001). Air temperature and relative humidity were measured by an Assman aspiration psychrometer (short measurements) and recorded weekly, on a continuous basis, by a thermohygrograph. The measurements were collected three times a day (in the morning, at noon, and in the evening) for 14 days during the season (autumn and winter). The measurements were taken at the height of porker backs at three places situated diagonally across the room (one in the centre, the second and the third at shorter walls). Analogous measurements were taken over the same time period for the external climate.
The results obtained were statistically analysed based on the work by Oktaba (1980), and Tr^towski and Wojcik (1991). The arithmetic mean (x) and coefficient of variation (V%) were calculated for the parameters describing external conditions (air temperature and relative humidity) over both seasons - autumn and winter. The parameter values were also subjected to one-way analysis of variance in order to compare means for those parameters over both seasons. The same procedure, that is calculation of arithmetic mean (x) and coefficient of variation (V%), was used to describe microclimatic conditions inside the buildings. Moreover, a two-way analysis of variance, including an interaction effect, was attempted to examine significance of an impact of seasons and buildings on air temperature and relative humidity. A detailed comparison of means for the parameters describing internal and external conditions was carried out by means of Tukey's test. Also, relationship between the external climate and the internal air physical parameters studied was determined using the regression coefficient (byx) which indicates what change in the dependent variable (parameter inside the buildings) follows from a unit increase in an independent variable (parameter outside the buildings), and the linear correlation coefficient (r) which measures the strength of a linear relationship between two variables, the significance of which being determined at the probability level of 0.05 and 0.01.
Results and discussion. Characterisation of the external climate during autumn and winter periods is presented in table 1.
Significant differences between average air temperatures during the autumn (3.91 °C) and winter (-2.43 °C) periods were found following the variance analysis. In contrast, no significant impact of seasons on internal air relative humidity levels was detected. Coefficients of variation calculated for the external climate indicated a higher differentiation of air temperature and relative humidity over winter, compared with the autumn.
The description of microclimate inside the buildings throughout autumn and winter are shown in table 2.
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Table 1
Characterisation of external climate over autumn and winter periods by means
of air temperature (°C) and air relative humidity (%)
Seasons Statistical measures Parameters examined
Air temperature Air relative humidity
Autumn x V% 3.91 b 23.0 86.9 a 10.8
Winter x V% -2.43 a 88.9 78.3 a 14.7
LSD0.05 1,93 insignificant differences
Explanations: a, b - means in columns followed by the same letter do not differ significantly (P<0.05).
Table 2
Characterisation of microclimate inside the buildings over autumn and winter periods by means of air temperature (°C) and air relative humidity (%)
Seasons Parameters examined
Buildings Air temperature Air relative humidity
Autumn 13.8 b 82.0 a
Winter 10.2 a 79.7 a
LSD0.05 0.6
A 15.8 c 77.6 a
B 13.0 b 81.2 a
C 9.8 a 82.0 a
D 12.4 b 80.2 a
E 9.0 a 83.3 a
LSD0.05 1.2 insignificant differences
Explanations: as in table 1.
A significant impact of the seasons on variation in average air temperature inside the piggeries was found on the basis of analysis of variance. The average air temperature inside the buildings examined was significantly higher in autumn (13.8 °C), compared with the temperature in the winter period (10.2 °C). The significantly lowest air temperatures were observed in buildings C and E (9.8 and 9.0 °C, respectively), and the highest temperatures were recorded in building A (15.8 °C). There was found no significant influence of seasons examined on variation in air
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relative humidity in the piggeries. Also, average values for air relative humidity did not differ significantly.
Table 3 presents the association of air temperature and relative humidity in piggeries, and external climate during the autumn and winter periods.
Air temperature inside the buildings over the periods examined fell within broad ranges and showed a dependence on external climate fluctuations. This inference can be made on the basis of average air values, coefficients of variation and correlation coefficients. Average air temperatures throughout autumn in buildings A, B, C, D and E amounted to, respectively: 17.4, 14.6, 11.6, 14.6 and 10.7 °C. Even lower were the values of this parameter recorded in winter. They amounted to: 14.1, 11.5, 8.0, 10.2 and 7.3 °C, respectively. The lowest air temperatures in both autumn and winter were found in buildings C and E. The most beneficial production results in pig production are obtained at the air temperature ranging from 15 to 23 °C (R^czkiewicz and Mardarowicz, 1984) whereas Dobrzanski and Kolacz (1996) give the most optimal range of 16 to 18 °C for these temperatures.
Table 3
Relation between air temperature (°C) and air relative humidity (%) in piggeries and external climate over the autumn and winter period
Buildings Statistical Air temi perature Relative air temperature
measures Autumn Winter Autumn Winter
x 17.4 14.1 78.4 76.9
A V% 4.9 7.7 5.8 7.5
byx 0.92 0.49 0.40 0.44
r 0.974** 0.986** 0.822** 0.897**
x 14.6 11.5 81.1 81.3
B V% 6.6 9.2 10.6 6.6
byx 1.01 0.46 0.67 0.40
r 0.940** 0.950** 0.734** 0.872**
x 11.6 8.0 83.0 81.0
C V% 7.9 16.6 8.8 7.0
byx 0.91 0.60 0.66 0.44
r 0.892** 0.975** 0.828** 0.898**
x 14.6 10.2 82.0 78.4
D V% 4.3 18.9 9.6 7.0
byx 0.43 0.86 0.69 0.41
r 0.607* 0.964** 0.820** 0.866**
x 10.7 7.3 85.6 81.0
E V% 14.8 8.1 8.0 7.7
byx 1.67 0.27 0.66 0.44
r 0.952** 0.967** 0.900** 0.818**
Explanations: - significant relation atP<0.05, - significant relation at P<0.01.
Average autumn air temperatures were within the range set by norms but in winter the parameter deviated markedly from the zootechnical norms, which indicated that the thermal autonomy of the buildings were low. It was also reflected in values of linear correlation coefficients which, in all of the buildings examined, were
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higher in winter. A strong association between the external climate and air temperature inside the buildings in winter was found especially for building D in which a 1 °C decrease in air temperature outside resulted in a reduced, by 0.86 °C, temperature inside the building.
Average relative air humidity during the autumn period in buildings A, B, C, D and E was: 78.4, 81.1, 83.0, 82.0 and 85.6%, respectively. In winter the parameter was at a level similar to the autumn level, with extreme values from 76.9% (building A) to 81.3% (building B). Throughout the period of pig fattening, extreme (max., min.) recommended values of relative humidity should range from 60 to 80% (Dobrzanski et al., 1981; R^czkiewicz and Mardarowicz, 1984; Iwanczuk et al., 1986; Dobrzanski and Kolacz, 1996). On the farms studied the parameter in autumn and winter reached the level of uppermost values or was slightly above the optimum norms. Both in autumn and winter a significant positive correlation was found (just like for the air temperature) between the relative humidity outside and inside the buildings. A 1% change in external humidity resulted in an analogous change in the humidity measured inside the building, ranging from 0.40 to 0.69% in autumn, and from 0.40 to 0.44% in winter.
Conclusions
1. In the winter period optimum norms for air temperature inside the buildings where pigs were housed were exceeded, which was connected with poor heat insulation.
2. Relative air humidity over both seasons of the year reached the uppermost levels of zoohygienic norms.
3. The external environment significantly affected air thermal and humidity conditions in piggeries in both autumn and winter.
4. The relation between air temperature and relative humidity inside the building and outside it was significant and positive. It means that a change in either external air temperature or relative humidity was followed by the same change in the parameters inside the buildings.
References
1. Bombik T., Kolbuszowski T., 1995: Bilans cieplny nieogrzewanych budynkow inwentarskich. WSRP, Siedlce.
2. Cena M., 1980: Srodowiskowe zagadnienia zoohigieny. AR, Wroclaw.
3. Dobrzanski Z., Grzegorzak A., Kolacz R., 1981: Wplyw zroznicowanych warunkow mikroklimatycznych na zdrowotnosc swin utrzymywanych w systemie bateryjnym. Medycyna Wet., 2, 82-84.
4. Dobrzanski Z., Kolacz R., 1996: Przewodnik do cwiczen z zoohigieny. AR, Wroclaw.
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6. Huynh T.T.T., Aarnink A.J.A., Gernts W.J.J., Heetkamp M.J.H., Canh T.T., Spodder H.A.M., Kemp B., Verstegen M.W.A., 2005: Thermal behaviour of growing pigs in response to high temperature and humidity. Appl. Anim. Behav. Sci., 91, 1-16.
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13. Tr^towski J., Wojcik A.R., 1991: Metodyka doswiadczen rolniczych. WSRP, Siedlce.
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Summary
Research was carried out in 5 piggeries characterised by similar technical solutions and stocking rate of animals. Over autumn and winter there were taken several times measurements of 2 physical parameters, that is temperature and relative humidity, both outside and inside the buildings.
The results obtained were subjected to statistical analysis which included calculation of basic characteristics, analysis of variance and linear correlation and regression.
Values exceeding optimum norms for air temperature inside the buildings for porkers were recorded, which resulted from poor building heat insulation. It was found that air relative humidity both in autumn and winter remained close to the uppermost values of zoohygienic norms. It was also ascertained that the internal climate significantly influenced thermal and humidity conditions in piggeries over both seasons examined, and changes in either internal air temperature or relative humidity were followed by analogous changes in the respective parameters measured inside the building.
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