The Development of the Environment Favourable to an Animal in a Cold Barn ; Aplinkos, palankios gyvuliui šaltoje karvidėje, formavimas

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• Publié par: lithuanian_university_of_agriculture
• Publié le: 01 janvier 2007
• Nombre de lectures: 39
• Langue: English

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LITHUANIAN UNIVERSITY OF AGRICULTURE    

Ernesta Liniauskien ė       THE DEVELOPMENT OF THE ENVIRONMENT FAVOURABLE TO AN ANIMAL IN A COLD BARN           Summary of the doctoral dissertation    Technological Sciences, Environmental Engineering and Landscape Management (04T)              

Academy, 2007

The work was written in 2002/2007 in Lithuanian University of Agriculture, Faculty of Agriculture Engineering, Department of Heat and Biotechnology Engineering.   Scientific supervisor: prof. dr. habil. Povilas Algimantas SIRVYDAS (Lithuanian University of Agriculture, Technological Sciences, Environmental Engineering and Landscape Management  04 T). Consultant: assoc. prof. dr. Rolandas BLEIZGYS (Lithuanian University of Agriculture, Technological Sciences, Environmental Engineering and Landscape Management  04 T).   Thesis will be defended at scientific board of the Environmental and Landscape Management, Lithuanian University of Agriculture: Chairman: prof. dr. habil. Č eslovas Linksmutis RAMONAS (Lithuanian University of Agriculture, Technological Sciences, Environmental Engineering and Landscape Management  04 T). Members: prof. dr. habil. Jonas Algirdas RAILA (Lithuanian University of Agriculture, Technological Sciences, Environmental Engineering and Landscape Management  04 T); prof. (HP) dr. Bronius BAKUTIS (Lithuanian Veterinary Academy, Biomedical Sciences, Veterinary Medicine  12 B); dr. (HP) Antanas Sigitas ILEIKA (Water Management Institute of the Lithuanian University of Agriculture, Technological Sciences, Environmental Engineering and Landscape Management  04 T); dr. (HP) Ignas ATEIKIS (Institute of Agricultural Engineering of the Lithuanian University of Agriculture, Technological Sciences, Environmental Engineering and Landscape Management  04 T). Opponents: prof. (HP) dr. Juvencijus Stanislovas DEIKUS (Lithuanian University of Agriculture, Technological Sciences, Environmental Engineering and Landscape Management  04 T); prof. dr. habil. Č eslovas JUKNA (Lithuanian Veterinary Academy, Zootechnical Sciences  13 B).   The official discussion will be held on the 11 of December 2007 at 10 a.m. in the meeting of the Environmental Engineering and Landscape Management board, 261 a. I nd building, Lithuanian University of Agriculture. Address: Student ų g. 11. LT-53067, Akademija, Kauno r., Lithuania.   Summary of the doctoral dissertation was mailed on the 09 of November 2007. The dissertation can be viewed in libraries of Lithuanian University of Agriculture and Water Management Institute of the Lithuanian University of Agriculture.

   

LIETUVOS EM Ė S Ū KIO UNIVERSITETAS               Ernesta Liniauskien ė       APLINKOS, PALANKIOS GYVULIUI ALTOJE KARVID Ė JE, FORMAVIMAS             Da ktaro disertacijos santrauka   Technologijos mokslai, aplinkos ininerija ir kratotvarka (04 T)                

 

Akademija, 2007

Disertacija rengta 2002  2007 metais Lietuvos em ė s ū kio universitete, em ė s ū kio ininerijos fakultete, ilumos ir biotechnologij ų ininerijos katedroje.   Mokslinis vadovas: prof.habil.dr. Povilas Algimantas SIRVYDAS (L Ū U, technologijos mokslai, aplinkos ininerija ir kratotvarka 04T). Mokslinis konsultantas: doc. dr. Rolandas BLEIZGYS   (L Ū U, technologijos mokslai, aplinkos ininerija ir kratotvarka 04T). Disertacija ginama Lietuvos em ė s ū kio universiteto Aplinkos ininerijos ir kratotvarkos mokslo krypties taryboje: Pirmininkas:  prof. habil. dr. Č eslovas Linksmutis RAMONAS (Lietuvos em ė s ū kio universitetas, Technologijos mokslai, aplinkos ininerija ir kratotvarka  04 T). Nariai: prof. habil. dr. Jonas Algirdas RAILA (Lietuvos em ė s ū kio universitetas, Technologijos mokslai, aplinkos ininerija ir kratotvarka  04 T); prof. (HP) dr. Bronius BAKUTIS (Lietuvos veterinarijos akademija, biomedicinos mokslai ir veterinarin ė medicina  12 B); Vyriausiasis m. d. (HP) dr. Antanas Sigitas ILEIKA (Lietuvos em ė s ū kio universiteto Vandens ū kio institutas Technologijos mokslai, aplinkos ininerija ir kratotvarka  04 T); Vyriausiasis m. d. (HP) dr. Ignas ATEIKIS (Lietuvos em ė s ū kio universiteto em ė s ū kio ininerijos institutas, Technologijos mokslai, aplinkos ininerija ir kratotvarka  04 T). Oponentai: prof. (HP) dr. Juvencijus Stanislovas DEIKUS (Lietuvos em ė s ū kio universitetas, Technologijos mokslai, aplinkos ininerija ir kratotvarka  04 T); prof. habil. dr. Č eslovas JUKNA (Lietuvos veterinarijos akademija, Zootechnika  13 B).   Disertacija bus ginama vieame Aplinkos ininerijos ir kratotvarkos mokslo krypties tarybos pos ė dyje 2007 m. gruodio m ė n. 11d. 10 val. Lietuvos em ė s ū kio universiteto, centrini ų  r ū m ų   261 auditorijoje. Adresas: Student ų g. 11. LT  53067. Akademija, Kauno r., Lietuva.   Disertacijos santrauka isiuntin ė ta 2007 m. lapkri č io m ė n. 9 d. Disertacij ą  galima peri ū r ė ti Lietuvos em ė s ū kio universiteto ir L Ū U Vandens ū kio instituto bibliotekose. 

 

 

INTRODUCTION

The relevance and substantiation of the topic Recently the tendency to keep animals in cold, newly-built airy barns is becoming stronger and stronger. However, while applying this technology of animal breeding, in the cold season we face unfavourable climactic conditions, i.e. the negative effect on an animals organism. If one wishes to diminish the negative effect of low temperatures on an animal, he/she must make sure that an animals organism is in a thermo steady condition, at the same time making an influence on energetic circulation between an animal and the environment. Only thermo steady condition which is also known as heat comfort ensures the complete functioning and productivity of an animals organism. Temperature is one of the most important factors of a barns microclimate. Controlling technological factors of a barn enables a person to influence the air temperature. If the temperature in the barn varies, the energetic circulation between an animal and the environment changes as well. Therefore, the need to solve this problem and base the means allowing to reduce the transmitting of heat that is in the cows organism when the temperature in the barn is low appears. One can significantly influence the exchange between an animal and the environment as well as the zone of heat comfort while replacing the heat exchange of an animal through the cubicle floor. Having this aim in mind, one should estimate the differences in air temperature, the heat emitted by the animal, heat insulation properties of the material used for animal mats as well as the thickness of this material. The work provided is aimed at developing and exploring of factors that make an impact on an animals comfort zone.

Aims and problems   The aim of the work is to substantiate the means used to expand the comfort zone of a cow heat analyzing thermo energetic processes that occur between a cow and the environment in cold barns. The following problems were solved: 1.   Estimation of the main micro climactic factors in cold barns in Lithuanian climactic conditions. 2.   Analysing the range of temperature in the cubicle floor of barns. 3.   Analysing the consistent patterns of heat exchange in various cubicle mats used in barns. 4.   Substantiation of the heat properties of material used for a mat in cold barns. 5.   Determining the possibilities to expand the heat comfort zone of a cow regulating the heat exchange through the cubicle floor.

Scientific originality and practical significance In Lithuania barns of a cold type started to be built only in the latter decade. Cold barns became the focal point of interest due to several reasons. First of all, they are built in a short period of time. In addition, three or four times lower constructing material and financial input is needed. Moreover, natural animal keeping conditions are coming back into use. In Lithuania,

people build cold barns in order to ensure animals well being. Ways of keeping animals are being modernized. New technologies are being   developed. Constructive element suitability of barns for Lithuanian climactic conditions must be substantiated so that these technologies could be successfully established in barns. The development of these innovations led to more detail, scientifically based research. Thus, thermo energetic processes that occur between a cow and the environment in cold barns are analysed in the thesis paper. The problem of cows heat comfort zone expansion in cold barns is solved. The importance of heat exchange from the cow through the cubicle floor was proved on the basis of theoretical, laboratory and industrial research. Besides, heat properties of material used for cows cubicle floor in cold barns to improve the wellbeing of animals in barns in the cold season were substantiated. The obtained results could be used to solve the problem of animals well being in cold barns.

The thesis statements of the paper: 1.   Temperature dependence on the surrounding air temperature. 2.   Temperature dynamics in the cubicle floor of cold barns. 3.   The substantiation of heat properties of the mats used in cold barns. 4.   The consistence of heat exchange of cows mats that are employed in cold barns. 5.   The heat properties of the cubicle is a significant factor able to make an impact on the cows heat comfort zone.

The approval of the paper 5 reports were read on the topic of the thesis paper in international scientific conferences. (Lithuania 2002, 2004, 2006; Latvia 2005). 5 publications were announced on the topic of the paper: three of them were published in the publications referred by the international database list approved by the Lithuanian scientific board, the rest two were published in other scientific publications.  

Work structure The work consists of introduction, research survey, work methodology description, results and their discussion, conclusions and the list of cited references. The work comprises 96 pages, 56 figures, 3 tables and 101 references.

SUMMARY In the first chapter  The analysis of information sources. Recently the cooperation between farmers and scientists has increased. Therefore, one strives to reach an agreement among the parameters such as animals well being, environment protection, the demand of the capital. As a result, a new approach towards the animals keeping conditions, constructive and technological decisions is disclosed. In numerous farms animals are already kept loose in airy, not warmed and cheap barns. Despite all advantages of this animal keeping technology, the main problem shows through in the winter being unfavourable climactic conditions in a barn, when the air temperature in a barn is lower than -10 o C and higher than 25 o C.

The main factor that creates unfavourable conditions in cold barns is the air temperature. Numerous research has been carried out to analyse the most important factor of barns microclimate  the air temperature, which directly influences an animals organism and other micro climactic factors in a barn such as relative air moisture and the amount of gas. If the temperature in a barn changes, the intensity of heat exchange between an animal and the environment alters as well. On the basis of the conducted surveys, the negative influence of high and low temperatures on an animals organism was proved. Usual functions of a cows organism are disordered and the milk yield significantly diminishes in both high and low temperatures of a barn. In Lithuania, in the winter period lower than -10 o C can be found in barns. Such air temperatures can make a negative impact on an animals organism. Thus, only the balance between an animal and the environment can ensure the thermo steady condition of its organism. When the amount of heat in the animals organism is steady, heat comfort is created for animals. Heat comfort zone (the minimal and maximal temperatures of the environment), where thermoregulation of a cows body takes place and the maximum productivity is obtained, is extremely important to an animals organism. The following factors can make an impact on the critical air temperature:   Heat insulation qualities of an animals skin • •   The consumption of food •   Bodys adaptation   The relation between the body surface and the mass of an animal • •   The speed of air movement •   Heat properties of cubicle floor. •   Heat exchange through radiance. The first four factors are closely related to the physiological condition of an animal. However, when other technological factors of a barn are influenced, the critical ambient temperature can be reduced as well, i.e. the minimal temperature that can be allowed in a barn can be reduced and animals heat comfort zone can be expanded. The air circulation in a barn is conditioned by the necessary air exchange in order to eliminate moisture. Therefore, air circulation in a barn cannot be much limited. The disadvantage of the heat by radiance can reduced by increasing the surface temperature of the constructions in a barn. On the other hand, such decision in cold barns is not economical. The demand for new technical solutions how to reduce the emission of cows heat to the environment the air temperatures in a cowshed being low appears. The emission of an animas heat to the environment and heat comfort zone can be significantly affected by replacing heat exchange of an animal through the cubicle floor. It is one of the most substantial solutions because animals spend 50 - 60 % of their time lying in the cubicle while their contact area with the floor reaches 1/5  1/6 of the surface area. Therefore, animals that lie on the cold floor (-15 o C) with poor heat insulation lose more heat than those that lie on a well-isolated floor. The emission of heat by conduction from an animals body through the cubicle floor can grow even up to 40 % of total heat emission. Striving to protect animals from harmful effect of low

temperatures, it is advisable to analyse possibilities to reduce critical air temperature in a barn and expand heat comfort zone controlling the exchange of heat through the cubicle floor. In the second chapter. In the Methodology of research attention is paid to the complexity of a problem which will be solved using theoretical and experimental methods. In this chapter the evaluation of theoretical and experimental methodology and measurement error is provided. Research of various material used for mats such as sand, sawdust, straw, rubber pellets, rubber mats, and concrete panel was carried out. In a laboratory stand we took measurements of temperature in nine points at the same time. We used the device called ALMEMO 2590-9 with microprocessor data processing and storing system to register our measurements. The measurement data was stored in the device ALMEMO that has 9 inlets for sensors connected with ALMEMO link (ZA 9020-FS). The measurements were made using thermocouples made of copper constant wire with the diameter of 0,09 mm. The temperatures were recorded every 2 minutes. In order to have steady resistance, the wire of the same length was used. The temperature was measured on the basis of the requirements for temperature measurements. Thermocouples were laid according to the isotherm with 100 diameters of thermo pores. In addition, the dynamics of heat flux from the heat source through various material used for animals mats was measured. The source of heat is the aluminum plate heated by electric heating element which has the power of 300 W. The constant temperature (with the accuracy of ±0,4 degrees) is maintained by using the digital controller E5CN. To measure the flux of heat, the measurer of heat flux Ahlborn FQ A020 C with the diameter of the active measurement plate of 23 mm was used while the density of heat flux being 104 W/m 2 corresponds to the voltage of 1mV. The accuracy of warmth flow measurer was ±5 %. Manufacturing experiments were performed in two different types of barns: a) in a reconstructed barn (the boxes are littered with straw) b) in a totally new barn (the boxes are laid by rubber mats). Form 2002 to 2006 in the cold season in barns we measured: •   The micro climactic factors of a barn (air temperature, relative moisture) •   Air climactic factors outside a barn (air temperature, relative moisture) •   The floor temperature of a box (contact temperature between a cow and the floor  the temperature on the rubber mat; the temperature under the rubber mat; the temperature under the littered straw). The temperature inside and outside the barn and relative moisture was recorded every hour while every 2 minutes in the box floor. Up-to-date devices were used to measure climactic indicators: accumulator 2590-9 as a measurer of temperature and moisture controlled by a computer, temperature sensor accumulator Drager Pac III-TRACER as a temperature measurer in the floor. All the research was conducted according to the deadline of methodology keeping to the research methodology. In the third chapter.  In the chapter The analysis of cows heat comfort zone expansion possibilities the process of heat emitted by an animals organism transferred to the animals skin is discussed. Moreover, the analysis of animals thermoregulatory mechanism is carried out on

the basis of which the thermo steady condition of an animals organism is estimated, i.e. the balance of an animals energetic circulation which makes an impact on the environment. Generalized theoretic research is provided, which allows us to claim that energy exchange occurs between an animal and its environment. The latter is described by the equations of energy balance. The equation of cows energy balance is generalized as the equation of heat balance:

              Σ Q =Q b - Q lv - Q sl - Q kt     0, (1)  =           Here Q b is total heat emitted by an animal that is radiated to the environment as a metabolic, W. Q n is the emission of heat into the environment (the sensible heat consists of heat transferring by convection, radiation and conduction), W. Q sl is the emission of latent heat flux (the heat is evaporated in the form of water vapour), W. Q kl is the other heat loss, which includes heat loss of the air inhaled, the one to heat drinking water and heat loss in combination with the production such as milk and excrements), W. On the basis of research results in literature, it was found that the biggest proportion of heat loss in the balance of an animals heat is composed by transfer of sensible ( Q lv = 65 - 70 %) and latent ( Q sl = 27 -30 %) heat. The rest heat loss ( Q kt = 1,5 - 2 %) with excrements as well as the one aimed at heating water and provender makes up a relatively insignificant proportion of heat balance. Therefore, while analyzing the animals heat balance and estimating the impact of the main factors, we agree that Q kl equates to 0. From the point of view of heat circulation in an environment, physiological cows condition is different when a cow lies and stands. A cow being in a standing or lying position, its surface contact area with the surrounding air and cubicle floor changes and, thus, unequal heat amount is emitted by convection, radiance and conduction from an the body surface of an animal. The equation of a standing cows heat balance is as follows:

Σ Q = Q b - (Q k1 + Q s1 ) - (Q g1 + Q kv ) = 0,                   (2) When a cow stands, its contact area with the floor is very small. In the standing position the total nail contact area with the floor is only 0,032 - 0,043 m 2 . The heat loss of a cow across this contact area will be lower than 0,3 % of the total cows heat loss. Therefore, heat loss of the floor by conduction when the cow stands could be rejected. After a cow lies down, the contact area with the floor is large, even 1m 2 (when a cow lies down, the heat amount emitted by conduction increases through the enlarged contact surface between a cows body and the cubicle floor). Therefore, it is necessary to estimate heat loss by conduction through the floor. The heat balance equation for a lying cow is written down as follows:

Σ Q = Q b - (Q k2 + Q s2 + Q l ) - (Q g2 + Q kv ) = 0,                 (3) In the equations (2) and (3) the loss of heat Q k , Q s , Q l , Q g is not equal in absolute value because the body surface area involved in the heat exchange process of a standing and lying cow is different. We accept the fact that heat loss into the environment in the form of vapor through the breathing system for the lying and standing cow will be constant ( Q kv =const.).

Ranging the air temperature, the heat emission from an animal to the environment will alter as well. Nevertheless, animals have a heat emission regulating mechanism due to which relatively constant body temperature can be maintained. When it changes, it affects the animal organisms heat emission to the environment. In general, the functional temperature dependence of an animals body surface can be expressed by the following equation:

 t = f(Q k ,Q s ,Q l ,Q g ,Q kv ,) (4)   In order to ascertain the influence of separate cows balance members in unfavourable conditions as well as to reduce heat loss through the cubicle floor and expand the heat comfort zone when animals are kept in cold barns in the winter, we carried out the analysis of exchange between a cow and the environment. The heat balance method which reveals the impact of a physiological condition of a cow (in a standing and lying position) on the heat loss to the environment was applied for the analysis. The result analysis of cows heat exchange with the environment in cold barns gave the following insights: •   When the air flux is perpendicular to the longitudinal axes of a cows body, convectional heat emission increases in 8,0-14,6 % in comparison with the flux parallel to a cows body. Thus, ventilation systems in barns should be projected so that air flux direction could be parallel to the longitudinal line of a cow. •   When the air temperature is close to zero, the flux of latent heat from a cow makes up more than 70 % of the total heat emission. Thus, if one wishes to diminish the loss of a cows heat in low temperatures, it is advisable to search for technical ways to control cows latent heat emission. •   The most significant factor that influences cows latent heat emission is the air temperature. When the air temperature falls from 32 o C to -20 o C, the density of heat flux increases from 19 to 250 W/m 2 . When the air temperature decreases in one degree, the density of heat flux increases in 4,5 W/m 2 . •   The analysis shows that the air temperature being lower than zero, there are theoretical possibilities to reduce cows heat loss in 250 W and to expand the heat comfort zone up to the temperature lower in 10 degrees.   When a cow lies down, the emission of latent heat will not increase the air temperature • being low in a barn if the heat emission coefficient will be no bigger than 4,6 W/(m 2. K) In the fourth chapter.  In the chapter The experimental evaluation of an environment favourable to an animal in a cold barn microclimate of cold barns is researched and discussed. One of the most important micro climactic factors in cold barns is internal air temperature. Short- termed variations of air temperature in a barn have a highly negative impact even on healthy and productive cows. Having explored the real situation in cold barns it was found that the lowest temperature occurs early in the morning from 3 to 5 a.m. when cows still have a rest. The range of the observed coldest temperature a day is provided in figure 1.

0 -5 -10

-15

-20

-25

Temperature inside Temperature outside Average inside Average outside

Time min.   Fig.1. The range of the coldest air temperature outside and inside the cold barn during the research period The coldest temperature was found at 4 a.m. when the temperature fell up to -14,6 o C. The coldest day temperature in a barn was 6,9 ± 1,3 o C higher than outside a barn in average. During the research while ranging air temperature outside and inside a barn, relative moisture changed, too. The average air temperature in a barn varied from -9,6 o C to 11,6 o C. The average relative moisture ranged between 67,4 to 95,2%. The average day temperature outside changed from to -15,2 o C to 8,3 o C while relative moisture varied from 75,4 to 98,1 %. It was identified that the air temperature range in a barn directly influences the range of relative moisture. Having expressed the range of temperature inside and outside a cowshed in a diagram form, we get linear subordination to the air temperature outside a barn (figure 2). 15 10 y = 0,8356x + 3,8695     5 R 2 = 0,96 0 -5 -10 -15 -25 -20 -15 -10 -5 0 5 10 Air temperature outside o C   Fig.2. The subordination of average day air temperature in a cold barn to the air temperature outside a barn Having estimated the microclimate in cold barns, we explored the cubicle floor in actual conditions when boxes are laid by 3 cm of rubber mats whereas concrete is littered by a 2 cm layer of straw. The research manifested the duration of a cows rest in boxes on various mats in relation to air temperature in a barn.