Abstract Small dairy farms in hot climes are meeting several jobs caused by the design defect of the enforced lodging designs. Consequently, heat stress addition and milk output dramatically decreases, which leads to economic lack of the farm. One cardinal issue is to develop simple agencies to rectify the design flaws with lower limit costs. In order to develop executable agencies, design defects were detected on-site in 14 little dairy farms in Egypt to represent the defects of lodging designs in waterless and semi-arid zones. A bundle of interrelated solutions is suggested to rectify the design defect. Subsequently, the maximal temperature, dry-bulb temperature, black-globe temperature, dew point, comparative humidness, shaded country, and air speed were measured inside the rectified vs. non-rectified cowbarns and compared after carry oning the statistical analysis. On the other manus, the Temperature-Humidity Index ( THI ) and Black Globe Humidity Index ( BGHI ) were calculated to happen out the degree of heat emphasis impacting the dairy cattles. Furthermore, the milk output, respiration rate, skin temperature, feed consumptions were recorded and compared. Furthermore, the costs of the developed agencies were calculated and a feasibleness survey was carried out. The consequences show that the developed agencies are effectual and executable, where the heat emphasis decreased ( THI decreased from 94.6 to 83.7 ; dry-bulb temperature decreased from 42.7 to 33.6 oC ) and the mean milk production increased from 18 to 26 kg/day.cow. Consequently, the costs were minimized and the grosss were maximized, which achieve economic efficiency for the farm where the net income increased by about 427 $ /cow.year.
Keywords: Heat Stress, Shade Structure, Roof Material, Cowshed Height, Shading Efficiency, Microclimate, Climate in Dairy Housing, Cooling System, Milk Yield, Costs.
Introduction Open lodging system is used in hotter climes, with changing systems of protection from heat emphasis, depending on the ambient temperature. An unfastened lodging system, in hot climes, consists of a pace shaded by a roof. This system allows air to travel in the infinite between the roof and the floor executing natural airing which enhances dairy cattles ‘ microclimate ( Hatem et al. , 2004a ; Hatem et al. , 2004b ; Hatem et al. , 2006 ) . However, the cowshed tallness should be between 5 and 8 m, sooner 8 m if the cowshed breadth is greater than 24 m ( Hatem et al. , 2004a ; Samer et al. , 2008d ) . Furthermore, the best suitable roof stuffs for waterless and semi-arid zones are reed and straw mats which are economically executable. In add-on, the shadowing efficiency should non be lower than 85 % and the shadiness construction should be oriented east-west where the largest country of the construction should confront the predominating summer air currents to let better aeration, and the distance between two cowbarns should ne’er be shorter than 15 m to avoid transporting the contaminated air from one cowbarn and distributing it into another one ( Hatem et al. , 2006 ; Samer et al. , 2008b ; Samer et al. , 2008d ) . Anyhow, the cattles ‘ standing degree should be lower than the degree of the feeding bunk by about 20 centimeter ( Hatem et al. , 2009 ) . Furthermore, the micro-sprinklers and fans chilling system is more applicable in waterless and semi-arid zones than the fog chilling system ; particularly, in unfastened lodging systems. In contrast, fog ( mist ) chilling system should be installed where comparative humidness degrees are sensible, and in entire or semi-confinement systems ( Samer et al. , 2008c ) . However, Samer et Al. ( 2008a ) stated that the manure should be hebdomadal scraped from the cow pens ( loose paces ) . This survey aims at appraising the direction lack and design defects of dairy lodging in hot climes, particularly waterless and semi-arid zones, and so suggesting simple and executable solutions in order to supply better microclimate which finally consequences in increasing the productiveness of the animate beings, i.e. the milk output.
Material and Methods The jobs were surveyed in several dairy farms. Subsequently, assorted solutions were developed and tested.
Surveyed Problems A study of design defects and direction lack has been carried out in 14 little dairy farms. The study ‘s consequences can be summarized as follows:
Shadowing. The shade construction does non supply the needed 85 % shading ( Fig. A.1a ) , as effects the cattles are crowded under shed in a little shaded country and the contact country among cattles ‘ organic structures additions, as consequences the heat emphasis additions due to the increasing heat exchange ; in add-on, several hurts were noticed on cattles ‘ organic structures.
Care. The roof covering stuffs are non maintained sporadically ( Fig. A.1b, and A.1c ) , which leads to expose the cattles to direct Sun radiation, increase Sun invasion, and cut down shadowing efficiency.
Covering Material. Corrugated aluminium still widely used as a covering stuff for the roof of shade constructions ( Fig. A.1d ) , though they have high thermal conduction which increases the heat emphasis that affects dairy cattles. This is finally diminishing the milk output.
Youngstock Housing. The youngstock are housed in metal boxes ( Fig. A.1e ) covered with metal sheets ( Fig. A.1f ) , which affects the growing and causes decease in some instances when these boxes are exposed to direct Sun radiation, other farms place the boxes under shadiness to cut down heat emphasis.
Feeding bunk. Several little dairy farms are holding a concrete base where the degree of the eating bunk is the same of the cattles ‘ standing degree and sometimes is lower ( Fig. A.1g ) , which forces the cattles to exercise attempts to make the eatage distributed into the feeding bunk i.e. uneasy-reach eatages.
Feeding Line. Some farms do non hold concrete eating line, i.e. the feeding line is flaxen ( Fig. A.1h ) , as consequence the dust emanation additions which affects the respiratory system of the youngstock and the dairy cattles.
Water Trough. Water escape from the H2O troughs is noticed in several farms, which wets the environing sand floor ( Fig. A.1k ) . The job is when the cattles lay down on a wet floor, their bags may be infected and encounter mastitis. Another job is that H2O troughs are in some farms exposed to direct Sun radiation i.e. the cattles are imbibing hot H2O, this increases heat emphasis.
Cooling System. Fog chilling system is widely installed and without fans ( Fig. A.1l, A.1m, and A.1n ) . However, this chilling system is non suited for the unfastened lodging system where the fog system is installed. Furthermore, this chilling system is inefficient under unfastened lodging conditions because of the external air which of course flows inside the unfastened lodging and take out the cooled air which surrounds the cattles to the exterior of the cowshed go forthing the cattles without chilling, i.e. under heat emphasis. This is due to the fact that fog chilling system is designed to be mounted straight under the shadiness construction, i.e. above the cattles by about 2.5 m ( Fig. A.1l ) ; where this system follows the theory of indirect chilling, in other words, it cools the air environing the animate being but non the animate being straight.
Manure Handling. The manure is scrapped monthly and seasonally in some farms ( Fig. A.1g ) , which consequences in polluting the cow ‘s organic structure and increasing the possibility of infecting the cow ‘s bag by mastitis. Another consequence is increasing the standing degree of the cattles to be the same as or higher than the feeding bunk degree.
Developed Solutions Several solutions were developed to rectify the design defect and direction lack of dairy farms in waterless and semi-arid zones. The solutions were implemented in the dairy farm under consideration where the experiments were carried out and can be represented as follows:
Shadowing. Fabric was installed to cover the unshaded countries ( Fig. A.2 ) , as a consequence the shading efficiency increased in comparing to non-rectified shed ( Fig. A.3 ) .
Care. The cowbarns holding straw or reed mats as covering stuff, their roof covering stuff was checked hebdomadal and maintained when necessary.
Covering Material. The cowbarns that have metal ( e.g. corrugated aluminium, metal sheets, etc… ) as roof covering stuff were covered by straw bales as insularity stuff over the roof, which decreases the convective and radiative heat transportation from roof to cattles. Furthermore, the straw bales were checkered hebdomadal and maintained when necessary.
Youngstock Housing. Fabric was installed on sidelong stations to cover the youngstock metal boxes, which consequences in cut downing their negative thermic effects on youngstock.
Feeding bunk. Normally the eating topographic points ( where the cattles stand to make the feeding bunk ) are sand floor which is the extension of the sand corral/yard. On the other manus, the eating bunks are concrete. The sand feeding topographic points were re-levelled to be lower than the feeding bunk degree by about 20 centimeter in order to supply easy-reach eatages.
Water Trough. New rainproof plastic troughs were installed under shadiness, and the old troughs were removed. The new troughs were checked on a regular basis for escape.
Cooling System. Fog chilling system was modified to micro-sprinklers and fans chilling system ( Fig. A.4 ) , by transporting out the undermentioned stairss: ( 1 ) new fans were installed 40 centimeter over the cattles, ( 2 ) the H2O line of the fog system was removed and reinstalled straight under the fans, ( 3 ) the foggers were replaced by half-circle ( 180o ) micro-sprinklers, ( 4 ) the force per unit area was reduced from 160 pounds per square inchs to 25 pounds per square inchs, ( 5 ) the nose ‘s discharge was increased from 7.6 gph to 30 gph, and ( 6 ) the other chilling system constituents ( thermoregulator, timer, H2O line, filter, solenoid valve, and force per unit area reducing agent ) were kept without alterations.
Manure Handling. Manure was hebdomadal scraped from the sand cow pens utilizing a scraper mounted following to tractor.
Testing the Developed Solutions Two similar cowbarns i.e. both have the same specifications, which are: ( 1 ) shed tallness is 3.5 m, ( 2 ) allotted country per cow is 20 m2/cow, ( 3 ) orientation is east-west, ( 4 ) shadiness construction is steel celebrity with corrugated aluminium as roof covering stuff, ( 5 ) sand floor cow pens system, and ( 6 ) each cowshed houses 10 Holstein Friesian cattles. The cowbarns were selected in the same dairy farm in order to guarantee that they are under the same climatic conditions ( wind velocity and way, external temperature and comparative humidness, and sun radiation ) . The first cowbarn, which had the aforesaid design defects, remained without alteration ( Fig. A.3 ) . The design defect of the 2nd cowbarns were rectified harmonizing to the developed solutions ( Fig. A.2 ) . The experiments were carried out in a little dairy farm ( 20 cattles ) 150 km North-West of the Egyptian capital Cairo, at longitude 29o59 ‘ Tocopherol and latitude 30o42 ‘ N, during summer months ( May – June – July – August – September of twelvemonth 2009 ) . The measurings were performed one twenty-four hours a hebdomad ( each Friday ) , five times along daytime in 3 hours intervals ( 07:00 am – 10:00 am – 01:00 autopsy – 04:00 autopsy – 07:00 autopsy ) .
The measurings were divided into measurings on cowbarns, measurings on microclimate, and measurings on animate beings. The whole measurings were quantified inside both cowbarns at the same clip. All informations were evaluated utilizing the SPSS plan and histograms were represented by the Microsoft Excel. The measurings on cowbarns were shadowing countries under the sheds. The shadowing efficiency was calculated for each shed five times a twenty-four hours by mensurating the shaded country under each shed and divided by the roof country multiplied by one 100. The measurings on microclimates were maximal temperature, comparative humidness ( RH % ) , dry-bulb temperature, black Earth temperature, dew point, and air speed. The measurings on animate beings were rectal temperature, skin temperature, respiration rate, milk production, and feed consumptions.
Sing the cowbarns, shaded country under sheds was measured by a tape. In relevancy to the clime in dairy lodging, maximal temperature was measured by max-min thermometer ; comparative humidness, dew point, and dry-bulb temperature were measured by digital hygrometer-thermometer device, and air speed was measured by vane wind gauge at the same aforesaid clip intervals. Refering the dairy cattles, Hatem et Al. ( 2004a ) Mentioned that tegument and rectal temperatures and respiration rate addition with the increasing of the ambient temperature ; accordingly, rectal temperature was measured by digital thermometer. The skin temperature was measured by infra-red thermometer. The respiration rate ( breaths/minute ) was determined by timed ocular numeration of flank motion. The milk production was recorded for each cow by the farm cardinal computing machine which receives informations from the milking parlor by a aglow storytellers overseas telegram, and feed consumption was recorded in the farm cardinal computing machine.
Two agencies were implemented to gauge heat emphasis ; the first 1 is calculating the Temperature-Humidity Index ( THI ) :
THI = Tdb + 0.36 Tdp + 41.2 ( 1 )
where, Tdb is dry-bulb temperature ( oC ) and Tdp is dew-point temperature ( oC ) .When THI is less than 72 there is no emphasis, between 73 and 77 there is a mild emphasis, between 78 and 88 there is a important emphasis, between 89 and 99 there is a terrible emphasis. If THI exceed 99 possible decease occurs ( Keown and Grant, 1999 ; Stowell et al. , 2001 ; Meyer et al. , 2002 ) . THI was computed for both sheds and the consequences were compared between them.
The 2nd mean is to cipher the Black Globe Humidity Index ( BGHI ) . Buffington et Al. ( 1981 ) proposed a BGHI by replacing the dry bulb temperature in equation ( 1 ) with a black-globe temperature. The BGHI is expressed as:
BGHI = Tbg + 0.36 Tdp + 41.2 ( 2 )
where, Tbg is the black Earth temperature ( oC ) and Tdp is the dew point temperature ( oC ) . The black-globe temperature was measured with a black Earth thermometer made of a black Cu ball about 15 centimeters in diameter with a temperature detector indoors. The black Earth integrates the effects of air temperature, solar radiation and convective chilling due to weave into a temperature value. Sing BGHI, the heat emphasis is classified into four general classs: Normal ( BGHI & A ; lt ; 74 ) , Alert ( 74 & A ; lt ; BGHI & A ; lt ; 78 ) , Danger ( 78 & A ; lt ; BGHI & A ; lt ; 84 ) and Emergency ( 84 & A ; lt ; BGHI ) .
consequences and treatment The norms of the different measurings throughout the summer ( Table 1 ) show that the developed solutions created important differences in the cattles ‘ microclimate. In add-on, Figure 1 shows extremely important differences among norms of maximal temperatures measured inside both cowbarns through summer months. Consequently, the milk output increased from 18 to 26 kg/day.cow as norm of 10 cattles in different production phases, i.e. in different DIM and seasons. Hence the net income is 8 kg/day.cow calculated for 305 days/year. The milk grosss were 634 $ /cow.year, and the entire costs of the developed solutions were 54 $ /cow.year ( Table 2 ) . Due to heightening the microclimate and cut downing the heat emphasis, the feed consumption increased by approximately 20 % , where eatage costs increased by 153 $ /cow.year. Therefore, the net income was 427 $ /cow.year. The cost inside informations are represented in Table 2.
Table 1. Average of the measurings at peak clip through summer months ( P & A ; lt ; 0.05 ) .
Dry-bulb Temperature ( oC )
Relative Humidity ( % )
Black Globe Humidity Index
Air Velocity ( m/s )
Shadowing Efficiency ( % )
Rectal Temperature ( oC )
Skin Temperature ( oC )
Respiration Rate ( breath/min )
The comparative humidness increased due to the chilling system alterations which changed the indirect chilling consequence to direct chilling by scattering the cattles straight. In contrast, the dry-bulb temperature decreased due to the combined effects of chilling, roof insularity, and the increased shading efficiency. The consequences shown in Table 1 are in understanding with Hatem et Al. ( 2006 ) , Samer et Al. ( 2008b ) , Samer et Al. ( 2008c ) , and Samer et Al. ( 2008d ) . Furthermore, THI changed from terrible to important emphasis, and BGHI changed from exigency degree to danger. However, the heat emphasis can be highly reduced if it is possible to increase cowshed tallness from 3.5 m to 5 or 8 m harmonizing to the cowshed breadth, but this measure is unpractical in instance of an already bing construction as in this farm ; hence, this specification raised by Hatem et Al. ( 2004a ) is unattainable.
An of import parametric quantity that should be taken into consideration to find the effectivity of the developed solutions is the maximal diurnal temperature inside both cowbarns. Figure 1 shows that maximal temperature was efficaciously decreased when the developed solutions were implemented. The differences were found extremely important.
Figure 1. Maximal temperature inside both sheds through summer months ( P & A ; lt ; 0.01 ) .
The capital investing with the fixed, variable, and entire costs of the enforced solutions/modifications are represented in Table 2. The values were calculated as sum for a cowbarn that houses 10 dairy cattles. Although the alterations of the chilling system represent the major part of the capital investing, they are extremely required due to their huge positive consequence on cut downing heat emphasis. On the other manus, manure managing consumes the chief portion of the variable costs ; however, manure handling is indispensable to supply healthful clean cow pens.
Table 2. The needed capital investing with the fixed, variable and entire costs.
Capital Investment ( $ )
( twelvemonth )
Fixed Costss ( $ /year )
Variable Cost ( $ /year )
Entire Costss ( $ /year )
per Cow ( $ /cow.year )
Textile ( incl. Youngstock )
Cooling System Modifications
Decision Rectifying design defects and direction lack of little dairy farms located in waterless and/or semi-arid zone enhances the microclimate and cow comfort. Consequently, the milk output additions. On the other manus, implementing the suggested solutions and simple agencies to repair the design defect was found to be economically executable. Therefore, the rectification costs were sensible in comparing with the tremendous milk output increase which finally consequences in privileged one-year net income per cow.