Changes In Temperature Humidity Index Research Articles

THERMAL STRESS PROJECTION BASED ON TEMPERATURE-HUMIDITY INDEX (THI) UNDER CLIMATE CHANGE SCENARIO

The degradation of green open spaces and the phenomenon of deforestation in Indonesia has increased discomfort in the region. Furthermore, if allowed to continue, the increase in temperature caused by greenhouse gases worsens the situation. Increased temperature and reduced air humidity are related to thermal stress, affecting human comfort and health. Thermal stress is measured based on the Temperature Humidity Index (THI), which calculates temperature and relative humidity variables. This study analyses THI projections under climate change scenarios RCP4.5 and RCP8.5. This study uses statistical downscaling and bias correction of Quantile Delta Mapping (QDM) to equalize the local climate. This study is divided into four 20-year periods from 2021 to 2100 to evaluate THI changes in future projections. Based on the study results, it is known that from 2041-2060, several big cities in Indonesia experienced an increase in THI and were included in the category of 50% of the population feeling uncomfortable. THI increased in the third and fourth periods. Areas that experienced a significant increase in THI were urban areas that lacked green open land and were densely populated. Surabaya City and Madura Island are the areas with the highest THI index.

Temperature and Temperature Humidity Index Changes during Summer to Autumn in a Temperate Zone May Affect Liveweight Gain and Feed Efficiency in Sheep

Lamb finishing during summer in southern Australia faces the challenges of dry paddock feed of low nutrient value and energy concentration, combined with periods of high temperature that reduce appetite. One potential forage to overcome these challenges is camelina, a brassica with a high lipid concentration. Liveweight gain (LWG) and feed efficiency (FE) of a pelleted diet containing 15% camelina hay (CAM) were compared with an equivalent diet based on oaten hay (STD), a feed commonly used during dry seasons. The experiment was conducted under summer to autumn conditions using 56 maternal Composite (Composite) wether lambs (4 months, 28–38 kg liveweight) and 56 Merino wether yearlings (15 months, 37–43 kg liveweight). Animals were maintained in group pens (8/pen) and weekly average feed intakes per pen and liveweights per pen were determined in a shaded well-ventilated animal house. The LWG and FE for both animal types were significantly lower during weeks 5–8 compared with weeks 1–4. These changes coincided with a higher proportion of daytime maxima exceeding 28 °C (50% vs. 21%) and night-time hours exceeding 22 °C (15% vs. 9%). The experiment indicated that the LWG and FE of sheep fed the CAM diet were less affected by the elevated temperatures than sheep fed the STD diet during weeks 5–8. However, further research under controlled environmental conditions is required to further validate these results.

THI Modulation of Genetic and Non-genetic Variance Components for Carcass Traits in Hanwoo Cattle.

The phenotype of carcass traits in beef cattle are affected by random genetic and non-genetic effects, which both can be modulated by an environmental variable such as Temperature-Humidity Index (THI), a key environmental factor in cattle production. In this study, a multivariate reaction norm model (MRNM) was used to assess if the random genetic and non-genetic (i.e., residual) effects of carcass weight (CW), back fat thickness (BFT), eye muscle area (EMA), and marbling score (MS) were modulated by THI, using 9,318 Hanwoo steers (N = 8,964) and cows (N = 354) that were genotyped on the Illumina Bovine SNP50 BeadChip (50K). THI was measured based on the period of 15–45 days before slaughter. Both the correlation and the interaction between THI and random genetic and non-genetic effects were accounted for in the model. In the analyses, it was shown that the genetic effects of EMA and the non-genetic effects of CW and MS were significantly modulated by THI. No significant THI modulation of such effects was found for BFT. These results highlight the relevance of THI changes for the genetic and non-genetic variation of CW, EMA, and MS in Hanwoo beef cattle. Importantly, heritability estimates for CW, EMA, and MS from additive models without considering THI interactions were underestimated. Moreover, the significance of interaction can be biased if not properly accounting for the correlation between THI and genetic and non-genetic effects. Thus, we argue that the estimation of genetic parameters should be based on appropriate models to avoid any potential bias of estimates. Our finding should serve as a basis for future studies aiming at revealing genotype by environment interaction in estimation and genomic prediction of breeding values.

Effects of THI changes on milk production and composition of three dairy cattle farms in Mugello from 2010 to 2018: a preliminary study

Submitted 2020-07-03 | Accepted 2020-09-09 | Available 2020-12-01 https://doi.org/10.15414/afz.2020.23.mi-fpap.167-173 Global warming is already affecting several areas and a further increase of 1.5°C is expected by 2050. Dairy cattle are particularly sensitive to high temperature. So, the aim of this study was to examine the effect of temperature-humidity index (THI) on milk traits, considering changes of climatic parameters in the different seasons from 2010 to 2018. The study was conducted in 3 farms located in a hilly-mountainous area of Tuscany, the Mugello, situated from 220 to 450 m above sea level. Data on average daily milk yield and composition were monthly collected in the 3 farms from 2010 to 2018, while climatic parameters were recorded by a climatic station located in the area of the farms. As regards the climatic parameters, no significant variations have been observed in the last decade. The THI calculated thanks to the recording of temperature and humidity of the weather station, during the warmest months, was high enough to cause heat stress. The milk quality traits declined when THI increased. In conclusion, there was not any evidence that global warming has been affecting Mugello, but, despite its altitude, high THI usually reached during spring and summer seasons are already high enough to cause heat stress and a further increase could worsen farm productivity. Keywords: climate change, milk quality, heat stress, dairy cow References Amamou, H. et al. (2019). Thermotolerance indicators related to production and physiological responses to heat stress of Holstein cows. Journal of Thermal Biology, 82, 90–98. https://doi.org/10.1016/j.jtherbio.2019.03.016 André, G. et al. (2011). Quantifying the effect of heat stress on daily milk yield and monitoring dynamic changes using an adaptive dynamic model. Journal of Dairy Science, 94(9), 4502–4513. https://doi.org/10.3168/jds.2010-4139 Bartolini, G. et al. (2012). Mediterranean warming is especially due to summer season. Theoretical and Applied Climatology, 107, 279–295. https://doi.org/10.1007/s00704-011-0481-1 Baumgard, L. H. and Rhoads, R. P. (2007). The effects of hyperthermia on nutrient partitioning. In: Proceedings of Cornell Nutrition Conference, Ithaca, New York, 93–104. Bertocchi, L. et al. (2014). Seasonal variations in the composition of Holstein cow’s milk and temperature-humidity index relationship. Animal, 8(4), 667–674. https://doi.org/10.1017/S1751731114000032 Bohmanova, J., Misztal, I. and Cole, J. B. (2007). Temperature-humidity indices as indicators of milk production losses due to heat stress. Journal of Dairy Science, 90(4), 1947–1956. https://doi.org/10.3168/jds.2006-513 Bouraoui, R. et al. (2002). The relationship of temperature-humidity index with milk production of dairy cows in a Mediterranean climate. Animal Research, 51(6), 479–491. https://doi.org/10.1051/animres:2002036 Das, R. et al. (2016). Impact of heat stress on health and performance of dairy animals: A review. Veterinary World, 9(3), 260–268. https://doi.org/10.14202/vetworld.2016.260-268 Fabris, T. F. et al. (2019). Effect of heat stress during early, late, and entire dry period on dairy cattle. Journal of Dairy Science, 102(6), 5647–5656. https://doi.org/10.3168/jds.2018-15721 Gauly, M. and Ammer, S. (2020). Review: Challenges for dairy cow production systems arising from climate changes. Animal, 14(S1), S196–S203. https://doi.org/10.1017/S1751731119003239 Hossein-Zadeh, N. G., Mohit, A. and Azad, N. (2013). Effect of temperature-humidity index on productive and reproductive performances of Iranian Holstein cows. Iranian Journal of Veterinary Research 14(2), 106-112. https://dx.doi.org/10.22099/ijvr.2013.1583 Herbut, P., Angrecka, S. and Godyń, D. (2018). Effect of the duration of high air temperature on cow’s milking performance in moderate climate conditions. Annals of Animal Science, 18(1), 195–207. https://doi.org/10.1515/aoas-2017-0017 Javed, K. et al. (2004). Environmental factors affecting milk yield in Friesian cows in Punjab, Pakistan. Pakistan Veterinary Journal, 24, 4-7. Polsky, L. and von Keyserlingk, M. A. G. (2017). Invited review: Effects of heat stress on dairy cattle welfare. Journal of Dairy Science, 100(11), 8645–8657. https://doi.org/10.3168/jds.2017-12651 Renaudeau, D. et al. (2012). Adaptation to hot climate and strategies to alleviate heat stress in livestock production. Animal, 6(5), 707–728. https://doi.org/10.1017/S1751731111002448 Rhoads, M. L. et al. (2009). Effects of heat stress and plane of nutrition on lactating Holstein cows: I. Production, metabolism, and aspects of circulating somatotropin. Journal of Dairy Science, 92(5), 1986–1997. https://doi.org/10.3168/jds.2008-1641 Rojas-Downing, M. M. et al. (2017). Climate change and livestock: Impacts, adaptation, and mitigation. Climate Risk Management, 16, 145–163. https://doi.org/10.1016/j.crm.2017.02.001 Silanikove, N. and Koluman, D. N. (2015). Impact of climate change on the dairy industry in temperate zones: Predications on the overall negative impact and on the positive role of dairy goats in adaptation to earth warming. Small Ruminant Research, 123(1), 27–34. https://doi.org/10.1016/j.smallrumres.2014.11.005 Spiers, D. E., et al. (2004). Use of physiological parameters to predict milk yield and feed intake in heat-stressed dairy cows. Journal of Thermal Biology, 29(7-8 SPEC. ISS.), 759–764. https://doi.org/10.1016/j.jtherbio.2004.08.051 Thornton, P. K. et al. (2009). The impacts of climate change on livestock and livestock systems in developing countries: A review of what we know and what we need to know. Agricultural Systems, 101(3), 113–127. https://doi.org/10.1016/j.agsy.2009.05.002 Zampieri, M. et al. (2016). Global assessment of heat wave magnitudes from 1901 to 2010 and implications for the river discharge of the Alps. Science of the Total Environment, 571, 1330–1339. https://doi.org/10.1016/j.scitotenv.2016.07.008 Â

Genetic variation in Nelore heifer pregnancy due to heat stress during the breeding season

The objective of the present study was to identify genetic variation in heifer pregnancy due to heat stress in Nelore cattle during the breeding season. The Nelore heifers were born between 2003 and 2013 on six farms located in three Brazilian States. Heifer pregnancy (HP) was analyzed as a binary trait, with a value of 1 (success) assigned to females that were diagnosed pregnant and a value of 0 (failure) assigned to those that were not pregnant after breeding season. A threshold-reaction norm model was adopted to estimate (co)variance components and genetic parameters over temperature-humidity index (THI) values for HP. On the phenotypic scale, HP of Nelore cattle was slightly reduced by the increase in THI values (-0.85%/THI). The posterior means of the heritability estimates ranged from 0.17 at THI 82.5 to 0.01 at THI 88. The mean genetic correlations for HP between different THI values were below the unity. The genetic correlation between extreme THI values (82.5 and 88) was -0.47 (0.10). Genetic variation in the response to heat stress and heterogeneity in the (co)variance components and genetic parameters were observed across the THI scale. The breeding values of animals for HP were sensitive to changes in THI, thus demonstrating an important effect of the genotype-by-environment interaction due to heat stress.

An in vivo model to assess the thermoregulatory response of lactating Holsteins to an acute heat stress event occurring after a pharmacologically-induced LH surge

Hyperthermia occurring 10–12 h after LH surge reduces quality of maturing oocyte, thereby reducing fertility. Objective was to examine consequences of an acute heat stress and the influence of certain hormones on the thermoregulatory responses of lactating cows during this critical period. Between the months of February through May, cows were transported to a facility and maintained at a temperature-humidity index (THI) of 65.9 ± 0.2 (thermoneutral) or exposed to changes in THI to simulate what may occur during an acute heat stress event (71–86 THI; heat stress); cows were rapidly cooled thereafter. Mixed model regressions with repeated measures were used to test respiration rates (RR) and rectal temperature (RT). Within 40 and 110 min of increasing THI, RR increased in a quadratic fashion (P < 0.001); RT increased by 0.04 ± 0.1 °C (P < 0.001) per unit THI. Changes in RR lagged THI and preceded rises in RT. Average THI 3-days before treatment (prior THI) influenced RR (P = 0.050) and RT (P < 0.001) changes. Increased RR was more noticeable in heat-stressed cows when prior THI was in the 40 s. Rectal temperature of heat-stressed cows was 0.8 ± 0.02 °C lower when prior THI was in the 40 s versus low 60 s. Levels of progesterone and luteinizing hormone before treatment were predictive of thermoregulatory response in heat-stressed cows. Rapid cooling decreased RR by 0.6 ± 0.1 bpm (P < 0.001) and RT by 0.02 ± 0.002 °C per min (P < 0.002). Speed and magnitude of thermoregulatory changes to an acute heat stress and after sudden cooling emphasizes importance of strategic cooling before ovulation. Efforts to do so when prior THI approaches levels expected to induce mild stress are especially important. Respiration rate is a useful indicator of the degree of hyperthermia a lactating cow is experiencing.

Continuous Respiration Rate Measurement of Heat-Stressed Dairy Cows and Relation to Environment, Body Temperature, and Lying Time

Abstract. This study uses a continuously sampling sensor to document the respiration rate dynamics of lactating dairy cows under conditions of heat stress. Previously available respiration rate data on lactating dairy cows had primarily been generated by manually counting flank movements at discrete points in time, typically several times per day. Continuous measurements provide much higher-resolution data over time. The primary objective of this study was to analyze these continuous respiration rate measurements in relation to ambient conditions, body temperature, lying time, and time of day. Better understanding continuous responses to heat stress may help synchronize cooling system operation to the cows’ need for heat stress relief. For 19 days during a summer season in Wisconsin, eight lactating Holstein cows were equipped with sensors designed to detect the abdominal expansion associated with breathing. An algorithm was developed to derive respiration rate from each sensor’s signal. To validate the accuracy of the sensor and algorithms, measurements from the sensor were compared to respiration rate measurements taken via visual observation. Overall, variation in continuously measured respiration rate corresponded to changes in temperature-humidity index (THI) and body temperature. However, respiration rate and body temperature also remained elevated at night despite decreasing THI. Keywords: Dairy cow, Heat stress, Physiological monitoring, Respiration rate, Telemetry, Wearable.

Temperature humidity index scenarios in the Mediterranean basin

The study was undertaken to describe the temperature humidity index (THI) dynamics over the Mediterranean basin for the period 1971-2050. The THI combines temperature and humidity into a single value, and has been widely used to predict the effects of environmental warmth in farm animals. The analysis was based on daily outputs of the temperature and relative humidity from the Max Planck Institute data using the Intergovernmental Panel on Climate Change Special Report Emission Scenario A1B. Data revealed a gradual increase of both annual and seasonal THI during the period under investigation and a strong heterogeneity of the Mediterranean area. In particular, the analysis indicated that Spain, southern France and Italy should be expected to undergo the highest THI increase, which in the last decade under study (2041-2050) will range between 3 and 4 units. However, only during summer months the area presents characteristics indicating risk of thermal (heat) stress for farm animals. In this regard, scenario maps relative to the summer season suggested an enlargement of the areas in the basin where summer THI values will likely cause thermal discomfort in farm animals. In conclusion, the study indicated that the Mediterranean basin is likely to undergo THI changes, which may aggravate the consequences of hot weather on animal welfare, performances, health and survival and may help farmers, nutritionists, veterinarians, and policy-makers to develop appropriate adaptation strategies to limit consequences of climate change for the livestock sector in the Mediterranean countries.

Absence of a causal relationship between environmental and body temperature in dairy cows ( Bos taurus) under moderate climatic conditions

1. Continuous body temperature records from dairy cows for 46 days of summer and contemporary data for climate temperature humidity index (THI) were analysed. 2. A large component of the body temperature data was not explained by changes in THI. 3. Outside a normal range of values (above 72 for THI and 39.05 °C for body temperature), there was evidence of a causal relationship with a time delay of about 120 min. 4. Both variables had a prominent circadian component, but these were more likely to be due to common and/or independent causes than to any direct relationship.

Effect of Heat Stress on Nonreturn Rate in Holsteins: Fixed-Model Analyses

The objective of this study was to examine the relationship between reproductive traits and heat stress. Nonreturn rate at 45 d (NR45) was analyzed in a fixed-effect model that included the temperature-humidity index (THI) from a nearby weather station as a measurement of heat stress. Data consisted of 150,200 first inseminations at first and later parities of 110,860 Holstein cows from 550 herds in Georgia, Tennessee, and Florida with weather information from 16 weather stations. THI on the day of the insemination, 2 d prior, 5 d prior, 5, 10, 20, and 30 d after insemination were studied as independent variables. The THI on the day of insemination showed the highest effect on NR45, followed by 2 d prior, 5 d prior, and 5 d after insemination, but no relationship was found with THI at 10, 20, and 30 d after insemination. NR45 showed a decrease of 0.005 per unit increase in THI on the day of insemination for THI >68. First and later parities presented similar thresholds but responded differently to an increase in THI, with NR45 being significantly lower and more susceptible to increases of THI in cows in their first parity than in later parities (0.008 vs. 0.005 decrease). Threshold for sensitivity to heat stress changed with the states, with Florida, Georgia, and Tennessee having thresholds of 70, 70, and 66, respectively. The decrease in NR45 per unit increase of THI was 0.007, 0.005, and 0.006 for Florida, Georgia, and Tennessee, respectively. With respect to only the Florida data, the final fixed-effect model used was NR45 = herd(year) + month(year) + month(year) + age(parity) + days in milk + 100d milk + THI + error. Animals with more than 150 d in milk (DIM) had a 0.16 lower NR45 than animals with less than 60 DIM at insemination. Lower milk-producing animals showed 0.08 higher NR45 than higher-producing animals. A difference of 0.10 in NR45 was observed between THI lower than 70 and THI 84. This variation in NR45 caused by THI changes is sufficient to merit further studies to examine genetic components of heat tolerance for this trait.