Lack of vegetation exacerbates exposure to dangerous heat in dense settlements in a tropical African city

Both climate change and rapid urbanization accelerate exposure to heat in the city of Kampala, Uganda. From a network of low-cost temperature and humidity sensors, operational in 2018-2019, we derive the daily mean, minimum and maximum Humidex in order to quantify and explain intra-urban heat stress variation. This temperature-humidity index is shown to be heterogeneously distributed over the city, with a daily mean intra-urban Humidex Index deviation of 1.2°C on average. The largest difference between the coolest and the warmest station occurs between 16:00 and 17:00 local time. Averaged over the whole observation period, this daily maximum difference is 6.4°C between the warmest and coolest stations, and reaches 14.5°C on the most extreme day. This heat stress heterogeneity also translates to the occurrence of extreme heat, shown in other parts of the world to put local populations at risk of great discomfort or health danger. One station in a dense settlement reports a daily maximum Humidex Index of >40°C in 68% of the observation days, a level which was never reached at the nearby campus of the Makerere University, and only a few times at the city outskirts. Large intra-urban heat stress differences are explained by satellite earth observation products. Normalized Difference Vegetation Index (NDVI) has the highest (75%) power to predict the intra-urban variations in daily mean heat stress, but strong collinearity is found with other variables like impervious surface fraction and population density. Our results have implications for urban planning on the one hand, highlighting the importance of urban greening, and risk management on the other hand, recommending the use of a temperature-humidity index and accounting for large intra-urban heat stress variations and heat-prone districts in urban heat action plans for tropical humid cities.

Efek Temperature Humidity Index terhadap Konsumsi Air Minum dan Performans Ayam Kampung Super dengan Pemberian Enkapsulasi Fitobiotik Minyak Buah Merah

Ayam kampung super merupakan salah satu ayam kampung yang ditingkatkan performannya dengan perkawinan silang. Akan tetapi, perkawinan silang tidak serta merta memperbaiki performan. Ada beberapa hal lain yang mempengaruhi performan yaitu lingkungan dan feed additive. Oleh karena itu, tujuan dari penelitian ini adalah untuk mengetahui pengaruh Temperature Humidity Index dan pemberian enkapsulasi fitobiotik minyak buah merah terhadap konsumsi air minum dan performans ayam kampung super. Materi yang digunakan adalah alat ekstraksi, alat dan bahan enkapsulasi, buah merah, kandang individu dan ayam kampung super serta pakan starter. Metode penelitian yang digunakan yaitu Rancangan Acak Lengkap 5 perlakuan dan 4 ulangan dengan uji lanjut Duncan Multiple Range Test. Pemeliharaan dilakukan selama 56 hari dengan Temperature Humidity Index yaitu 24,44 - 35,21 oC. Hasil penelitian menunjukan bahwa penambahan enkapsulasi buah merah tidak berpengaruh terhadap konsumsi air minum (P>0,05), konsumsi pakan (P>0,05), feed conversion ratio (P>0,05) dan berpengaruh nyata terhadap pertambahan bobot badan (P<0,05). Berdasarkan hasil penelitian dapat disimpulkan bahwa kondisi lingkungan dilokasi penelitian (Papua) relatif ekstrim dilihat dari selisih THI. Selain itu, berdasarkan uji lanjut bahwa penambahan enkapsulasi fitobiotik minyak buah merah terhadap penambahan bobot badan menghasilkan perlakuan terbaik pada penambahan 2,5% enkapsulasi minyak buah merah.

Assessing the effect of barns structures and environmental conditions in dairy cattle farms monitored in Northern Italy

Animal welfare is a fundamental pillar for livestock farming, and it can be endangered by a series of aspects, among which is the presence of undesired microclimates. This condition can be monitored by measuring the temperature-humidity index (THI), an index able to inform about the emergence of heat-stressing conditions in the barns. The THI can be influenced by the external environmental conditions and the barn structure, orientation, thermal buoyancy, and roof insulating materials. In order to evaluate these structural aspects of buildings and the consequent microclimate, in this study, a survey was carried out in 8 dairy cattle barns located in the northern part of Italy that were monitored continuously during thermoneutral, warm, and cold periods. Experts observed the structural aspects ,and the environmental parameters were measured with sensors. From the results emerged that the barns had structural characteristics that considerably affect the internal microclimate, with openings, roof height, forced ventilation, and building orientation playing a significant role in estimating of the THI in the barn. The more critical period was the warm one when the structures could not mitigate the external conditions, and THI exceeded the threshold of 72 for a big share of the period in all monitored farms (range between 50-80% of observations). In the best situation, the cooling systems were able to maintain the external conditions. The results confirm the importance of the barn design and of an appropriate ventilation to improve air exchanges.

Comparative Analysis of the Cooling Efficiency in Tropical Climate of Three Alternative Materials for Evaporative Cooling Pads

A comparison between commercial cellulose evaporative cooling pad and pads manufactured with three alternative materials was made for environmental conditions typical of tropical countries. Wind tunnel tests were carried out to compute the convective heat and mass transfer coefficients and to measure the pressure drop across each pad, obtaining expressions that can be used as reference for future simulations. Using a mathematical model, a detailed analysis of the efficiency, Temperature–Humidity Index, temperature drop and relative humidity through the pads was performed in terms of different operative and constructive conditions, such as air velocities, dry-bulb temperatures, relative humidity and pad thickness. Significant differences between the pressure drop across the pads were found, which increases with the inlet air velocity and water flow. A weak relation between the analysed variables and the inlet air velocity was found, while a high correlation between the analysed variables, pad thickness and the external environmental conditions was established. Cooling efficiencies above 40% and a Temperature–Humidity Index below the mild zone of thermal stress were obtained for the alternative panels. Although the cellulose cooling pad showed the best behaviour in all aspects, the alternative pads can be used as substituted in specific applications to reduce the Temperature–Humidity Index inside agricultural facilities.

Auswirkungen der globalen Erwärmung auf die Haltung landwirtschaftlicher Nutztiere in Stallungen

&lt;p&gt;Schweine und Gefl&amp;#252;gel werden vorwiegend in geschlossenen Stallungen gehalten. Aufgrund der W&amp;#228;rmeabgabe der Tiere liegt die Stalltemperatur in herk&amp;#246;mmlichen Stallungen im Sommer mindestens 2 bis 3&amp;#176;C &amp;#252;ber der Au&amp;#223;entemperatur, was die Hitzebelastung der Tiere deutlich erh&amp;#246;ht. Sie reagieren auf Hitzestress durch Einschr&amp;#228;nkungen des Wohlbefindens (z.B. vermehrtes Hecheln), verringerte Leistung (Mast- und Legeleistung) und gesundheitlichen Beeintr&amp;#228;chtigungen bis hin zu erh&amp;#246;hter Mortalit&amp;#228;t.&lt;/p&gt; &lt;p&gt;Die Auswirkungen des Klimawandels auf die Tierproduktion k&amp;#246;nnen nicht unmittelbar aus den Klimamodellen abgeleitet werden, sondern bed&amp;#252;rfen komplexer Stallklimamodelle. Das verwendete Simulationsmodel beschreibt den Zusammenhang zwischen Tierbestand, l&amp;#252;ftungstechnischer Anlage und thermischen Geb&amp;#228;udeeigenschaften. Das Modell wird durch Stundenwerte von meteorologischen Parameter angerieben und simuliert das Stallklima anhand der thermisch-hygrischen Parameter und der Luftqualit&amp;#228;t. Die Beurteilung, ob Hitzestress f&amp;#252;r die Tiere auftritt, erfolgt anhand von Parametern wie z.B. dem Temperatur-Humidity-Index. &amp;#160;&lt;/p&gt; &lt;p&gt;Um den Hitzestress zu reduzieren wurden Adaptationsma&amp;#223;nahmen auf ihre Tauglichkeit untersucht. Dazu z&amp;#228;hlen energiesparende Luftaufbereitungssysteme (z.B. evaporative K&amp;#252;hlung), Ma&amp;#223;nahmen die die Geb&amp;#228;udeeigenschaften umfassen (z.B. Orientierung, Dachbegr&amp;#252;nung), Ma&amp;#223;nahmen die das Mikroklima modifizieren (z.B. Hochdruckvernebelung) und Managementma&amp;#223;nahmen (z.B. F&amp;#252;tterung).&lt;/p&gt; &lt;p&gt;F&amp;#252;r den Landwirt sind Informationen &amp;#252;ber das Auftreten von Hitzestress nur von mittelbarer Bedeutung, da daraus keine Handlungsmaximen abgeleitet werden k&amp;#246;nnen. Auf Basis der zu erwartenden Ver&amp;#228;nderungen der &amp;#246;konomischen Leistung (bspw. des Deckungsbeitrags) kann der Landwirt jedoch entscheiden, ob der Einsatz von Adaptationsma&amp;#223;nahmen &amp;#246;konomisch sinnvoll ist. Dazu wurde anhand einer einfachen Modells f&amp;#252;r Hitzestressparameter eine Projektion f&amp;#252;r 2030 vorgenommen und die Wahrscheinlichkeit des &amp;#246;konomischen Risikos im Hinblick auf die Verringerung des Deckungsbeitrags untersucht. &amp;#160;&lt;/p&gt; &lt;p&gt;Neben den Auswirkungen des Hitzestresses auf die Tiere wurde auch das Emissionsverhalten von Stallungen f&amp;#252;r Ammoniak (NH&lt;sub&gt;3&lt;/sub&gt;) und Geruchstoffe untersucht. Geruchstoffe k&amp;#246;nnen im Nahbereich zu Geruchsbel&amp;#228;stigungen f&amp;#252;hren. NH&lt;sub&gt;3&lt;/sub&gt; bewirkt einen Stickstoffeintrag und stellt eine Vorl&amp;#228;ufersubstanz f&amp;#252;r Feinstaub dar. Die Freisetzung von Geruchstoffen und NH&lt;sub&gt;3&lt;/sub&gt; h&amp;#228;ngt von der Stalltemperatur und der Turbulenz im Stallraum ab. Daher wurde anhand eines Modells untersucht, wie sich die Emissionen zwischen 1981 und 2017 entwickelt haben. Im Hinblick auf die notwendige NH&lt;sub&gt;3&lt;/sub&gt; Reduktion&lt;/p&gt;

Effect of Temperature-Humidity-Index on Milk Performances of Local Born Holstein Dairy Cows Under Saharan Climate

The objective is to study the effect of heat stress on milk yield (MY) relative to milking records (n=18178) of native Holsteins (n=187), in the region of Ghardaia, according to periods of HS, using the temperature-humidity index (THI). With THI >72 during 07 months in the study area, which significantly (P<0.001) decrease the MY (-15.5% corresponding to 21.73 kg). Also, calving periods led to a significant drop (P < 0.001) in overall MY (7030.35 kg) of the order of (-14.6%), and over the lactation length (353.43 d), which explains 41% of the variations in MY. In addition, the non-significant effect (P=0.212) of the lactation range on the increase in MY, moreover, the lactation length shows a non-significant (P = 0.108) decrease (-4.68%) during heat stress (HS). Furthermore, the significant effect (P <0.001) of the interaction (Milking frequency × THI) on MY, when THI variates from < 74 to > 84, with regression of (-16.82% and -08.82%) of the MF (2X and 3X), respectively. Again, the NH cow is less sensitive to hyperthermia, so THI explains only 2% of the variation in MY levels. Thus, NH in arid regions have the ability to acclimatize to Saharan environmental conditions.

Improved reproductive performance achieved in tropical dairy cows by dietary beta-carotene supplementation

Dairy farming in tropical climates is challenging as heat stress can impair reproduction in cows. Previous studies have demonstrated the beneficial effects of beta-carotene supplementation on bovine reproductive performance. This study was performed in Thailand, where the temperature-humidity index (THI) during the experimental periods was measured to range from 78.4 to 86.1. Lactating Holstein cows classified as repeat breeders (previous artificial insemination [AI] failures) were randomly assigned into two treatments, control treatment (T1; received placebo, n = 200) and test treatment (T2; received 400 mg/h/day of beta-carotene, n = 200). All cows were subjected to a protocol for synchronization of ovulation and timed artificial insemination (TAI). The day of the 1st ovulation synchronized protocol was defined as day 0, and the total experimental period was 160 days. Daily placebo or beta-carotene supplements were given orally on day 0 and each subsequent day of the experiment. Diagnosis of pregnancy was performed using ultrasound on day 30 after insemination. Non-pregnant cows were subjected to further ovulation synchronizations (maximum of four) and TAI over a period of 160 days. Milk samples were collected every ten days throughout the experiment. The samples were analyzed for beta-carotene concentration, superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. The pregnancies per AI of the cows in T2 were significantly greater than that of T1 from the 2nd to 4th TAI. During the entire experimental period, the pregnancies in T2 were significantly greater than that of T1. Cox's proportional hazards regression model data indicated a 44% greater probability of pregnancy for cows receiving beta-carotene. The concentrations of milk beta-carotene in T2 were significantly greater than T1 from the 2nd to 4th TAI. Significantly greater SOD and GPx activities were observed in T2 than T1, suggesting a reduction of oxidative stress in cows treated with beta-carotene. Dietary supplementation with beta-carotene thus improves the reproductive performance of repeat breeders exposed to heat stress, possibly by reducing oxidative stress.