EFFECT OF A WATER-COOLED COVER ON THE THERMAL COMFORT OF PREGNANT SOWS IN HOT AND HUMID CLIMATE (original) (raw)
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Field evaluation of a water-cooled cover for cooling sows in hot and humid climates
Biosystems Engineering, 2011
The hot and humid summer climates in certain parts of China can adversely impact on the production and welfare of gestating sows. Hence, effective cooling means to alleviate heat stress are essential to pig production. A field experiment was conducted to evaluate the efficacy of a water-cooled cover (WCC) attached to the sow's stall with regards to thermal microenvironment in the sow occupied zone (SOZ), and the physiological and behavioural responses of the sows. The results showed that black-globe temperature (BGT) in SOZ under WCC with or without the presence of the sow averaged 4.8 or 5.4 C below that of the control (without WCC) when the indoor air temperature was 34.3 C. The temperature reduction in SOZ was proportional to the temperature difference between the inlet and outlet water of WCC. Increasing water flow rate through WCC enhanced cooling efficiency up to 4 l min À1 beyond which little additional benefit could be gained from further increase in water flow rate. Respiratory rate and surface temperature of the sows with access to WCC were significantly lower than those for control group (P < 0.001). The WCC sows spent 74% of their time lying under WCC, while the control sows spent 94% of the time lying in the pen. The sow's thermoregulatory responses and behaviours were observed to lag 1e3 h behind the peak air temperature. Results of the present work suggest that WCC can alleviate heat stress of gestating sows in hot and humid climates. journal homepa ge: www .e lsev ie r.com/locate/issn/153 75110 b i o s y s t e m s e n g i n e e r i n g 1 1 0 ( 2 0 1 1 ) 4 1 3 e4 2 0 1537-5110/$ e see front matter ª
2017
A study was conducted to assess the effect of evaporative cooling system (ECS) on the performance of sows during summer season and to determine the temperature-humidity index (THI). Ninety-one sows were used in the study, 49 sows were housed with ECS throughout gestation (T1) and 42 in conventional housing system all throughout gestation period (T2). The THI in T1 and T2 ranges from 73.31-80.47 and 75.23-82.66 respectively. Results showed that ECS significantly affects the birth weight, back fat thickness at weaning, and weaning to estrous interval of sows but did not have a significant effect on the gestation period, weaning weight, back fat thickness at farrowing, litter size born alive, litter size at weaning, total pigs born, and number of born dead. There was also a 0.75-day difference in the weaning to estrus interval from T1 was also observed. Partial budget analysis revealed that Php 25,634.33 per year per house was added to the net profit of the farm due to the reduction in...
Characterisation of an experimental water-cooled cover for sows
Biosystems Engineering, 2010
Heat stress relief for sows in hot and humid climates remains a challenge. This study investigates a cooling method that is intended to enhance heat dissipation from sows. The experimental device was an aluminium cover (1.5 m long by 0.65 m wide and either 0.8 m or 0.95 m high) fitted with water-cooled pipes (25 mm diameter, spaced at 100 mm, 150 mm or 200 mm) and attached to the frame of the gestation sow crate. Performance was evaluated for cooling water temperatures of 15 or 20 C under ambient summer conditions.
Heat Loss in Lactating Sows under Different Ventilation Systems and Diets during Summer
2012 IX International Livestock Environment Symposium (ILES IX), 2012
The experiment was conducted in a commercial farm and aimed to evaluate the heat loss and thermoregulation parameters from lactating sows under two ventilation system (natural or evaporative cooling) and two diets (natural or adjusted electrolyte balance) in the summer. Variables related to performance and thermal regulation were recorded during the 20-day lactation. Respiratory rate was recorded along with the recording of skin surface temperature and rectal temperature in the afternoon. Calculations were performed considering the heat exchange balance. Data were analyzed using Minitab 15 ® . Evaporative cooling led to a reduction (p<0.05) in respiratory rate, rectal temperature and skin surface temperature of the sows and increased the sow's heat loss. However, the dietary electrolyte balance did not cause significant difference in these variables. It was concluded that the use of evaporative cooling system helped to reduce heat effects on the sows' thermoregulation. In the diet with adequate nutritional levels for hot climates, the adjustment of the electrolyte balance did not show benefits in minimizing the effects of heat stress.
Effect of floor cooling on performance of lactating sows during summer
Livestock Science, 2006
Forty Landrace × Large White lactating sows were used to evaluate the effects of cooling of the floor when maintained under high temperature conditions during summer on their productive and reproductive performance. The sows were allocated in a completely randomized design with two treatments with 20 replicates according to parity number and body weight, with each animal being considered an experimental unit. The treatments consisted of cooling of the floor under the sow with water circulation at about 17°C and no cooling. The resulting temperatures of the floor were 27.6 and 35.8°C for the cooled and the control treatments, respectively. The sows from both treatments were exposed to average maximum and minimum environmental temperatures of 26.9 and 20.8°C, respectively. Sows maintained on a cooled floor had a higher feed intake (6.47 vs. 5.61 kg/day; P b 0.01). Despite this higher intake, sows maintained on a cooled floor had higher body weight and body protein losses during the lactation period (P b 0.01) in connection with a higher milk yield and subsequent growth of the litter (2280 vs. 1798 g/day; P b 0.01). There was an effect of treatment on rectal temperature, surface temperatures and respiratory rate (P b 0.01) with lower values in sows submitted to floor cooling. It is concluded that floor cooling under the lactating sow improves its productive and reproductive performance, as well as the performance of its litter.
Pigs are more sensitive to high environmental temperatures explained by the inability of sweating and panting properly when compared to other species of farmed livestock. The evaporative cooling system might favor the thermal comfort of animals during exposure to extreme environmental heat and reduce the harmful effects of heat stress. The purpose of this study was to assess the sensible heat loss and thermoregulation parameters from lactating sows during summer submitted to two different acclimatization systems: natural and evaporative cooling. The experiment was carried out in a commercial farm with 72 lactating sows. The ambient variables (temperature, relative humidity and air velocity) and sows physiological parameters (rectal temperature, surface temperature and respiratory rate) were monitored and then the sensible heat loss at 21days lactation was calculated. The results of rectal temperature did not differ between treatments. However, the evaporative cooling led to a significant reduction in surface temperature and respiratory rate and a significant increase in the sow's sensible heat loss. It was concluded that the use of evaporative cooling system was essential to increase sensible heat loss; thus, it should reduce the negative effects of heat on the sows' thermoregulation during summer.
Cooling ventilation at farrowing for sows from first to third parturition
Comunicata Scientiae
This study aimed to evaluate the thermal comfort considering natural and cooling ventilation on the performance, physiological parameters and thermal comfort indices for sows from first to third parturition. A total of 30 sows from commercial lineage (genetic base Landrace x Large White) initially weighing 252.3±5.7, 280.8±9.5 and 324.5±4.8 kg at first, second and third parturition, respectively, were distributed in a 3x2 factorial arrangement, considering the three parturition orders and the two ventilation methods, with five replicas per treatment. The effect of ventilation methods and times of the day on relative humidity, radiant thermal load, temperature and humidity index and black globe humidity index. There was an interaction among ventilation methods and parturition order for sow weight at weaning and daily feed intake. Regarding the females physiological parameters, with the exception of rectal temperature, there was an interaction between ventilation methods and times of ...
Use of different cooling systems by pregnant sows in experimental pen
Biosystems Engineering, 2009
Literature suggests that pregnant sows are able to select the types of cooling they prefer in the pen. This hypothesis was tested by comparing different cooling regimes. A fixed group of four pregnant sows was selected; six cycles of observations were carried out during summer. Inside the pen, four areas were selected and treated with different regimes; not cooled, cooled with an airstream, cooled with an airstream and water on the floor, and cooled with water on the floor. The use of the different areas by the sows was monitored in relation to air temperature and the temperature-humidity index .
Journal of Animal Science, 2021
This study was conducted to evaluate whether cooled floor pads combined with chilled drinking water could alleviate negative impacts of heat stress on lactating sows. Thirty sows (Landrace × Yorkshire, Parity = 1 to 6) were housed in individual farrowing stalls in two rooms with temperatures being controlled at 29.4°C (0700–1900 hours) and 23.9°C (1900–0700 hours). Sows in one room (Cool), but not in the other room (Control) were provided cooled floor pads (21–22°C) and chilled drinking water (13–15°C). Behavior of sows (15 sows/treatment) was video recorded during farrowing, and days 1, 3, 7, 14, and 21 after farrowing. Videos were viewed continuously to register the birth time of each piglet, from which total farrowing duration and birth intervals were calculated. The number of drinking bouts and the duration of each drinking bout were registered for each sow through viewing videos continuously for 2 h (1530–1730 hours) each video-recording day. Postures (lying laterally, lying ve...