Responses of Piglets to Creep Heat Type and Location in Farrowing Cage

Comparative tests were conducted in an environment–controlled farrowing room [21C (70F)] to determine the choice of mat heat vs. lamp heat by piglets in farrowing crates. Two widened farrowing crates [2.40 Ü 2.13 m (8 Ü 7 ft] were used, each equipped with two double–size heat mats [0.6 Ü 1.2 m (2 Ü 4 ft) 120–W capacity each]. One mat was powered to provide the localized heat, while the other simply served as a floor mat with a 175–W heat lamp suspended 76 cm (30 in.) above it for localized heat. Both heat sources were placed along one side of the sow; hence one mat was closer to the posterior of the sow than the other. The heat source located near the posterior of the sow was clearly preferred by piglets regardless of its type. Lamp heat was used significantly more than mat heat for the first two days after birth. Surface temperatures of piglets and heat sources were quantified. In particular, surface temperature of piglets resting under the heat lamp decreased linearly with the distance between the piglets and the center of the heat source, ranging from 39.4 to 33.4C (103 to 92F)

Real-time Assessment of Swine Thermal Comfort by Computer Vision

Interactive assessment and control of swine thermal comfort by real-time computer image analysis of pig resting patterns is investigated. The new approach overcomes pitfalls inherent of conventional method in that it uses the animals themselves as an integral biosensor versus the partial air temperature as used in conventional method. The behavior-based system consists of a CCD camera; an image grabber board inside a PC; and a visual C++ program that performs acquisition, processing and classification of animal behavioral images. Critical and challenging to robust operation of this real-time system is proper image feature selections that have little dependence on growth and thus changing body size of the pigs. Image processing algorithms of the system were developed with paper-cut pigs in laboratory settings and briefly validated with live pigs in production settings. Further refinement of the prototype is needed before it can be used in commercial production settings

Temperature-Humidity-Velocity Index for Market-size Broilers

A temperature-humidity-velocity index (THVI) for male broilers (46 ± 3 d; 2.8 ± 0.1 kg; Ross × Ross breed) was established based on body temperature (tb) rise of the bird during acute exposure to 18 thermally challenging conditions. The thermal conditions consisted of 18 factorial combinations of 3 dry-bulb air temperature (tdb, 35, 38, and 41 oC), 2 dew-point temperature (tdp, 19.4 and 26.1 oC), and 3 velocity (V, 0.2, 0.7, and 1.2 m/s). The THVI has the form of 058 . 0 ) 15 . 0 85 . 0 ( - × × + × = V t t THVI wb db (where twb = wet-bulb temperature). Homeostasis state of the bird was classified as normal, alert, danger, or emergency that corresponds to a tb rise threshold of 1.0, 2.5, 4.0 or \u3e4.0 oC. These different homeostasis states are functionally and graphically expressed in terms of THVI and exposure time. The results of this study provide a scientific basis for making management decisions and risk assessment associated with marketsize broiler production and handling under adverse thermal conditions

Heat and Moisture Production of Poultry and Their Housing Systems—A Literature Review

An extensive literature review and comparative analysis of heat and moisture production of various poultry types and their housing systems are presented. From each published article, the data extracted included breed, body mass (M), and age of the birds; temperature, RH, and photoperiod maintained during the study; measured values of latent heat (LH), sensible heat (SH) and total heat (TH) production; the type of study used (direct vs indirect calorimetric studies); feeding regimen (ad-libitum vs restricted); number of birds used; duration of the study and the type of waterers used. LH, SH and TH were explicitly indicated in some articles while in others, regression equations were published. Specific total heat production (THP, W/kg) was observed to have increased over the years in all poultry types. Specifically, THP increased by about 21 to 44% over a 14-year period (1968 to 1982) for broilers weighing 0.1 to 1.6 kg and by 15 to 22% for broilers at 1.4 to 1.6 kg over a 32 year period (1968 to 2000). Only one study was found for pullets and data were thus insufficient to draw any conclusions about the trend of THP. Data for pullets & layers between 7 and 33 wk old at thermoneutral environment are not available. Tom turkeys weighing 0.4 to 1.0 kg experienced an increase in THP of 36 to 63% over a 24-year period (1974 to 1998). Data for heavier turkeys were insufficient to make reasonable comparisons in the trend of THP. The metabolic rate equations derived from the literature data were in good agreement with the standard metabolic rate HP (W/bird)= a M b, where b = 0.66 to 0.75. Specifically, it was 10.60 M 0.74(1982 to 2000) and 8.31 M 0.71(1968) for broilers; 6.20 M 0.71for pullets and layers; and 9.83 M 0.74 (1992 to 1998) and 7.74 M 0.48(1974 to 1977) for turkeys

Field Evaluation of a Sprinkling System for Cooling Commercial Laying Hens in Iowa

An economical, low–pressure (276 kPa, 40 psi) sprinkling system was tested for its efficacy of cooling laying hens in a commercial high–rise layer house [14 Ü 130 m (46 Ü 426 ft)] in Iowa. The sprinklers, rated at 2.1 mL/s (2 gal/h) each, were equally spaced at 3 m (10 ft) apart and 2.4 m (8 ft) above the floor in each cage aisle of the layer house. They were controlled to operate 10 s every 10 min when the inside temperature exceeded 32 _ C (90 _ F). The system was shown to improve egg production by 2.6% overall and 5.6% for the top deck (P \u3c 0.01). There was no sign of sprinkling damage to eggshell integrity. Autocorrelation analysis has the potential to quantify the impact of heat stress history on subsequent egg production response of the hen. Work is needed to optimize the layout of the sprinklers for uniform water distribution and water application rate as a function of environmental conditions

Effects of Stocking Density and Group Size on Thermoregulatory Responses of Laying Hens under Heat Challenging Conditions

Sectors of the US cage layer industry have begun adopting practices of reduced stocking density (i.e., increased cage floor space) and varying group sizes. This study was conducted with 24 groups of 48 W-36 laying hens (39 to 46 weeks old) to assess the effects of cage floor space or stocking density (SD) (348, 387, 465, or 581 cm2/bird; 54, 60, 72, or 90 in2/bird) and group size (GS) (8 or 16 birds/cage) on the ability of the hens to cope with heat challenge. Data were collected at thermoneutral (24oC or 76oF) and warm conditions (32oC or 90oF and 35oC or 95oF). No differences in core body temperature (CBT) of the hens were observed among the treatment regimens at 24oC. In general, mean CBT increased with heat exposure duration (P\u3c0.0001) but leveled off after the 32oC phase. At 32oC, CBT was higher for GS of 16 vs. 8 (42.3 vs. 42.1oC, P=0.05); higher for SD of 348 and 387 cm2/bird than for 465 or 581 cm2/bird (42.4 and 42.2oC vs. 41.9 and 42.1oC, respectively, P=0.009). Bird body mass decreased as heat exposure duration increased (P\u3c0.0001), but no differences were observed among the treatments. No mortalities were observed during the thermoneutral period, and the mortality rate increased with heat exposure duration. The results indicate that, while CBT was lower for lower stocking density, the increased space was not sufficient to offer a clear benefit for coping with heat challenge of 32oC or 35oC

Development of a Novel Environmental Preference Test System for Laying Hens and Its Initial Application to Assess Hen Aversion to Atmospheric Ammonia

An environmental preference test chamber (EPTC) was designed, constructed, and utilized in an initial test for response of laying hens to atmospheric ammonia. The EPTC featured four interconnected, individually ventilated clear acrylic compartments. Each compartment contained a wire-mesh cage that was divided into two sections, one section used for a test bird to navigate between the compartments and the other section used for three stimulus birds to reside in each compartment. The EPTC was designed to assess individual bird preference without isolation effects. The section dividers may be removed to assess group preference. An initial experiment was conducted with six test hens to assess bird aversion to atmospheric ammonia. Each hen was trained to navigate the inter-compartment door prior to the aversion test. Following one day of acclimation to the chamber, behavioral data of the hen were collected for 2 days at ambient conditions (baseline) and 3 days at ammonia level of 25 ppm vs. \u3c10 ppm. Hen location (compartment) was documented and compared for baseline and treatment periods. All hens learned to navigate the chamber within 10 h; 4 of the 6 hens learned within 2 h. No preference for the level of ammoniated condition was observed with regard to occupancy of the corresponding compartment or number of entries into each environment. Further investigation is warranted to determine if this finding is a lack of aversion or other phenomenon. The EPTC will also enable future users to examine preference responses of hens to other environmental conditions, such as thermal comfort vs. air quality

Resting Behavior of Piglets in Farrowing Crates Equipped with Heat Mats

In-barn tests were conducted to study the resting behavior of piglets on heat mats in swine farrowing crates. An environmentally controlled farrowing room was set at 21.C (70.F) to simulate winter conditions in farrowing barns. Two enlarged crates [1.94 . 2.13 m (6.4 . 7 ft)] were used in the tests and each crate had a 0.6- . 1.2-m (2- . 4-ft) electrically heated mat. Mat surface temperatures of 33.C (91.F) and 35.C (95.F) were tested. Resting patterns of piglets on heat mats were recorded on videotapes using a time-lapse VCR and were subsequently analyzed. Heat mats provided a comfortable thermal environment to piglets as a low degree of huddling (10%) was observed. A difference of 2.C (3.6.F) in mat temperature (33.C vs. 35.C) caused no differences in the resting behavior or growth of the piglets. Piglets spent more time nursing than resting on heat mats during the first 24 h after birth. Heat mat usage by piglets was high (\u3e50%) from day 2 to 5 and it started to decrease thereafter, a result of less need for heat as piglets grow. The area occupied by piglets on the mat averaged 0.044 m2/pig (0.47 ft2/pig) and 0.074 m2/pig (0.80 ft2/pig) for 1- and 14-day old piglets, respectively. The dynamic heat mat use behavior of the piglets indicated that a mat size of 0.37 m2 (4 ft2), as typically used in current commercial production facilities, could accommodate most of the space needs of a litter of 12 piglets; but larger mats (e.g., 0.56 m2 or 6 ft2) would be advisable to ensure the well-being of piglets under unfavorable (cool or drafty) environmental conditions when the mat needs to accommodate the entire litter simultaneously

Heat and Moisture Production of Molting Laying Hens

Heat and moisture production rates (HP, MP) of modern 68- to 75-week-old Hy-Line W- 36 laying hens during the molting stage were measured using large-scale indirect calorimeters that mimic commercial production settings. The HP and MP were measured continuously during acclimation, fasting, restricted feeding, and postmolt or normal periods. Total HP (THP) was partitioned into latent and sensible HP (LHP, SHP), which incorporated the influence of fecal moisture evaporation. THP during fasting (averaging 4.8 W/kg) and restricted feeding (averaging 6.0 W/kg) periods averaged 29 and 13% lower than that during postmolt period (averaging 6.8 W/kg). Correspondingly, LHP averaged 1.9 W/kg and 1.8 W/kg and was 31 and 34% lower than that during postmolt period, which averaged 2.7 W/kg. Likewise, SHP averaged 2.9 W/kg during fasting period and was 28% lower than during postmolt period, which averaged 4.1 W/kg. The average SHP between restricted feeding and postmolt periods were similar (4.2 vs. 4.1 W/kg, respectively). The respiratory quotient (RQ) averaged 0.71, 0.76, and 0.92 during fasting, restricted feeding, and postmolt periods, respectively. HP values during the light period were significantly higher (P\u3c0.05) than those during the dark period. The daily mean and diurnal LHP as a percentage of THP were similar during fasting and postmolt periods and were comparatively 10% lower during restricted feeding period. The results of this study provide a new thermal load database for design of building ventilation systems for laying hens undergoing molting phase

Cooling Caged Laying Hens in High-rise House by Fogging Inlet Air

Cost effective and easy-to-retrofit cooling systems are needed for heat stress relief of laying hens in the Midwest of the United States. This field study evaluates the efficacy of cooling ventilation air by high-pressure (6,893 kPa or 1,000 psi) foggers installed along the eave air inlets of a commercial high-rise layer house (100,000 Hy-Line W-98 hens). Fogging was controlled to operate when the house temperature exceeded 30°C with a concomitant relative humidity (RH) of \u3c76%. The system was able to lower the inside air temperature by up to 7°C as compared to the outside temperature, depending on outside RH. The one-year (1999) test results showed that the system has good potential to be a viable alternative cooling system for the region. Further testing of the system, particularly its longevity and maintenance requirements, is warranted