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 Laying Hens by Intermittent Partial Surface Spraying

This study investigated the efficacy of intermittent partial surface sprinkling to cool caged layers at 20, 38, and 56 weeks of age. Ten birds were used per age group with two birds per paired trial (Experiment, Expt, and Control, Ctrl) that were subjected to an acute heat exposure of 40.0 ± 0.5°C air temperature, 45 ± 3% RH, and air velocity of 0.15 to 0.20 m/s for a maximum of 8 h. The Expt birds were sprinkled with water mist (8 mL/sprinkling session) on the head and appendages at 15-min intervals from the time when panting was observed; whereas, the Ctrl birds received no sprinkling. Continuous measurement of the rectal temperature and periodic thermographical measurement of the surface temperature of the birds were performed. The intermittent partial surface sprinkling had the following merits as compared with the control: lower body temperature rise (4.3 vs 5.7°C; P \u3c 0.05), higher lethal heat load threshold (10.0 vs 6.6°C-h, P \u3c 0.05), longer survival time (145 to \u3e 480 vs 92 to 266 min), and reduced mortality (20 to 60% vs 100%). The maximum reduction in surface temperature of the head and appendages due to the sprinkling averaged 2.2°C. Under the present environmental conditions (i.e., 40°C, 45% RH, and 0.15 to 0.20 m/s), sprinkling once every 5 to 6 min would provide adequate cooling to prevent the surface temperature from rising. The concept of body heat load ( â) seems to provide an effective measurement of heat tolerance of the birds under different cooling schemes

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

Rural structures in the tropics: Design and development

There is a growing awareness of the need for better rural structures and services in many developing countries. Here the FAO presents an up-to-date, comprehensive text focusing on structures for small- to medium-scale farms and, to some extent, village-scale agricultural infrastructure. The book will help to improve teaching on the subject of rural buildings in the tropics and will assist professionals engaged in providing technical advice. Importantly, it also provides guidance in the context of disaster recovery and rehabilitation, for rebuilding the sound rural structures and related services that are key to development and economic sustainability

Effect of Partially Covering Turkey Litter Surface on Ammonia Emission

Volatilization and ammonia (NH3) gas emission rate (ER) from poultry manure or litter is influenced by numerous factors including the nature and area of the emitting surface. In this study, the effect of the amount of exposed surface area of turkey litter on NH3 emission was investigated. Samples of turkey litter were obtained from stockpiled litter for a turkey growout barn. The study was conducted in four environmentally-controlled emission chambers maintained at 21±1oC and a concomitant relative humidity of 50±5%. Four different treatments were investigated where 0% (Control), 25%, 50% and 75% of the litter surface area was covered with plywood boards. The boards were periodically shifted to different positions to simulate movement of the turkeys in the barn. The NH3 concentration, litter temperature, air temperature and airflow rate through each chamber were measured continuously over a 6-d experimental period and replicated 3 times. NH3 ER was calculated from the concentration and air-flow data. The results revealed that the initial placement of the covers on the litter suppressed NH3 ERs to varying degrees. The covers served as physical barriers to NH3 emission and tended to temporarily reduce and delay of the emission but did not affect the overall total NH3 emission. Periodic shifting of the covers resulted in the escape of NH3 trapped underneath the covers resulting in similar overall NH3 ERs among the different treatments. The NH3 ER was linearly related to litter temperature, moisture content, storage time and pH and these relationships have been developed

Ventilation Rates of a Laying Hen House Based on New vs. Old Heat and Moisture Production Data

Heat and moisture production rates inside animal confinement provide the basis for design and operation of the building ventilation system. This article describes ventilation rate (VR) requirement by a modern high-rise layer (Hy-Line W-36 breed) house based on sensible heat and moisture production rates (SHP, MP) that were newly collected at the bird level or room level – designated as the new data vs. those collected some years ago – designated as the old data. The effects of bird stocking density on VR and balance temperature, tbal (outside temperature below which supplemental heat is needed to maintain the target house temperature) were also examined. The VR values cover an outdoor air temperature range of -25.C to 20.C (-13.F to 68.F) at 5.C (9.F) increments, an outdoor relative humidity (RHo) range of 20% to 70%, and indoor RH (RHi) of 50%, 60%, 70%, or 80%. Use of the old room-level SHP and MP led to a 10% higher VR for temperature control but a 18% lower VR for moisture control, as compared with use of the new data. Similarly, use of the old bird-level SHP and MP led to a 5% higher and a 57% lower VR for temperature and moisture control, respectively. These outcomes arose from the lower SHP but higher MP of modern layers and their housing systems. The results reaffirm the need to use updated room-level SHP and MP in ventilation design and operation of production housing systems. A 31% reduction in cage stocking density by increasing floor space from 355 to 465 cm2/hen (55 to 72 in.2/hen) would reduce VR for temperature control by 6% to 8% and elevate tbal by 1.0.C to 2.4.C (1.8.F to 4.3.F) for a target house temperature of 15.C to 25.C (59.F to77.F) and RHi of 50%. The elevation in tbal can be compensated by temporarily raising RHi setpoint when copying with unusually cold weather

Heat and Moisture Production and Minimum Ventilation Requirements of Tom Turkeys During Brooding-growing Period

Heat and moisture production rates of Nicholas tom turkeys raised under lab-scale commercial production settings were continually measured during a five-week brooding-growing period. Functions were established that relate age and body mass (BM) of the birds to their specific total heat production rate (THP), sensible heat production rate (SHP), moisture production rate (MP), and CO2 production rate. MP of the current study included both latent heat loss of the birds and evaporation of moisture from the litter and drinkers. Comparison of the HP and MP data from the current study with those in the ASAE Standard (EP 270.5) for BM = 0.1 to 1.1 kg revealed a 4% (for BM = 0.1 kg) to 282% (for BM = 1.0 kg) higher MP and a 2% to 107% lower SHP for the current study. THP from the current study was generally greater (up to 49%) than that in the Standard except for younger birds (\u3c 0.1 kg) whose THP was 36% less than that in the Standard. THP of the experimental tom turkeys peaked near two weeks of age. Compared with the literature data, HP and MP characteristics of the litter-grown young turkeys more closely resemble those of equal BM broilers raised on litter (Reece and Lott, 1982). Minimum ventilation rates (MVR) based on the new MP data for the five-week brooding-growing period were determined and tabulated for selected cold outside conditions and thermoneutral inside conditions. There were substantial discrepancies in MVR between the literature (MWPS, 1990) recommendations and the values derived from this study, with the literature MVR being 20 to 557% of the derived MVR. The age- or BM-dependent MVR obtained from the current study provide a new, convenient reference for ventilation design and operation of turkey brooder houses. Moreover, the equations of CO2 production rate from this study provide a practical tool for estimating ventilation rates in naturally ventilated brooder facilities. The results further revealed the urgent need to systematically update the literature HP and MP data for ventilation design of animal structures so that modern genetics, nutrition, housing systems, and management schemes can be more realistically reflected

Heat and Moisture Production of Poultry and Their Housing Systems: Pullets and Layers

Heat and moisture production rates (HP, MP) of modern pullets and laying hens were measured using large-scale indirect calorimeters that mimic commercial production settings. The experimental birds were Hy-Line W-36 strain at 1-5, 10, 21, 37, and 64 weeks of age and Hy-Line W-98 strain at 1-5 weeks of age. Total HP (THP) was partitioned into latent and sensible HP (LHP, SHP) at bird level (excluding moisture evaporation from feces) or room level (including fecal moisture evaporation from feces). The W-98 and W-36 pullets reached their metabolic peak at about 10 and 14 days of age, respectively. The W-98 pullet showed higher THP than the W- 36 counterpart. Modern pullets have significantly higher THP (12% to 37%; P \u3c 0.05) than pullets of 20 to 50 years ago. At the initial stage of egg production, the W-36 layers showed 12% higher THP than that predicted by the CIGR (1999) model, and the difference diminished with time. Evaporation of fecal moisture elevated room LHP by 8% to 38% (average 14%) during light period and by 21% to 79% (average 43%) during dark period but reduced room SHP by 4% to 17% (average 11%) during light period and by 14% to 33% (average 22%) during dark period with reference to bird LHP or SHP. All HP responses in the dark were significantly (P\u3c0.05) reduced to various degrees (e.g., 23% to 34% for THP) as compared with those during light period. Diurnal bird and room LHP amounted to, respectively, 17% to 87% (average 47%) and 33% to 99% (average 62%) of THP for pullets and, respectively, 29% to 50% (average 39%) and 29% to 55% (average 45%) of THP for laying hens. Respiratory quotient (RQ) ranged from 0.77 to 1.18 (average 0.94) for pullets and from 0.68 to 1.02 (average 0.91) for laying hens. Regression functions that relate daily mean THP, LHP, and SHP of the bird or room to bird body mass were established. Results of this study provide an updated thermal load database for design and operation of poultry housing ventilation systems, as well as the latest bioenergetics of modern pullets and hens

Current state and updating of heat and moisture production of poultry and their housing systems

An extensive literature review and comparative analysis of heat and moisture production (HP, MP) of various poultry types (layers, broilers, and turkeys) and their housing systems indicated that total heat production (THP, W/kg) has increased over the years by about 15 to 44% (1968 to 2000) for broilers, and by 36 to 63% (1974 to 1998) for tom turkeys. The metabolic rate equations derived from the literature data were 8.55 M0.74 (1968) and 10.62 M0.75 (1982 to 2000) for broilers; 6.47 M0.77 for pullets and layers (1953 to 1990); and 7.54 M0.53 (1974 to 1977) and 9.86 M0.77 (1992 to 1998) for turkeys. HP and MP of modern pullets (W-36 and W98) and W-36 laying and molting hens were measured. THP was partitioned into latent and sensible HP (LHP, SHP) for the bird (excluding moisture evaporation from the feces) or the room (including fecal moisture evaporation). The W-98 pullet produced higher THP than the W36 counterpart. Modern pullets showed higher THP (12--37%) than those 20 to 50 years ago. At the beginning of egg production, THP of the modern layers was 12% higher than that predicted by the CIGR (1999) model and the difference diminished with time. Evaporation of fecal moisture elevated room LHP by 8--79% and reduced the room SHP by 4--33% with reference to bird LHP or SHP. THP for molting hens ranged from 4.4 to 5.6 W/kg, 5.4 to 6.5 W/kg, and 6.7 to 6.9 W/kg during fasting, restricted feeding and post molt periods, respectively. LHP ranged from 1.7 to 2.1 W/kg, 1.5 to 2.0 W/kg, and 2.4 to 2.9 W/kg during the respective periods. The corresponding SHP ranged from 2.6 to 3.5 W/kg, 3.9 to 4.6 W/kg, and 3.9 to 4.4 W/kg, respectively. Results of this study provide an updated thermal load database for design and operation of poultry housing ventilation systems, as well as bioenergetics information for the scientific literature. Ventilation curves based on the new HP and MP were developed for 37week old W-36 hens housed at currently practiced stocking density and a recommended stocking density. The result revealed little influence of stocking density on supplemental heat requirement

Effects of Post-weaning Nutritional Conditions on Isowean Pigs

This study quantifies the responses of isowean pigs to post-weaning nutritional conditions as may be encountered during extended shipment. PIC breeding stock pigs at 8 to 12 days of age (3.5 to 4.0 kg body weight) were subjected to four nutritional regimens for 72 h. The pigs were then raised with ad libitum feeding for 14 days. Thermoneutral environments were used throughout the experiment. Pigs deprived of feed and water (i.e., Fast) had higher body weight loss (of 0.61 kg/pig or 17% of their initial body weight) as compared with pigs provided with feed and water supplement (0.39 kg/pig or 11% of their initial body weight) or water supplement only (0.43 kg/pig or 11.5% IBW) (P \u3c 0.05). All the treatments led to significant rise in blood urea nitrogen but fall in blood glucose (P \u3c 0.05). However, the glucose levels were much higher than the generally considered hypoglycemic level (75 mg/dL). All pigs showed a similar degree of dehydration, as evidenced by elevated hematocrit and blood electrolyte concentrations (P \u3c 0.05). The physiological responses returned to normal during the 14-day growth period and were similar for all the pigs. The results suggest that isowean pigs (PIC genetic line) responded well to post-weaning nutritional conditions typically encountered during extended shipments. Supply of bacteria-resistant water supplement such as Aqua-Jel seemed beneficial in reducing stress and may be considered for extended commercial shipment. However, in-transit supply of feed added little benefit to the pigs and thus may be omitted. This omission has special implications for international shipments because certain countries prohibit inclusion of feed in shipment. The energetics data of this study may be used to design and operate ventilation systems in transportation and production facilities for the isowean pigs