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Temperature-Humidity Index (THI) chart (based on Thom, 1959). Associated Livestock Weather Safety Index (LWSI; LCI, 1970) categories are also shown.
Citations
... As for the single positions, we calculated these metrics for the groups of steps preceding and following each position. Finally, we categorised each position for the individual cow, Julian date, hour, 'day-period' (day and night), slope expressed in degrees and obtained from a Digital Terrain model with a resolution of 25 m provided by the Natural Park 'Parco Naturale Paneveggio Pale di San Martino' (https://siat.provincia.tn.it/stem/), and the hourly Temperature Humidity Index (THI; Hahn et al. 2009;Rashamol et al. 2019), calculated from data of the weather station of Passo Rolle (46 � 17'52.5" N, 11 � 47'13.6" ...
This study explored the suitability of a commercial biologging system incorporating GPS and heart rate (HR) sensors to monitor grazing cattle’s movement, behaviour and heart rate. We preliminarily tested the GPS accuracy with stationary tests and then monitored six dairy cows grazing in an alpine summer pasture for 20 days and nights. We trained a random forest model on direct observations to infer cows’ behaviours (resting, grazing, walking) from GPS movement data. We associated each GPS position with the HR (beats per minute - bpm) mean and maximum-minimum difference in the 120–second interval preceding its acquisition. The GPS sensor showed high accuracy (positioning error lower than 2 m in open sky-view and 3 m under tree canopy cover) and efficiency of position acquisition of 95% after excluding outlier positions. The efficiency of HR data acquisition was lower, peaking at 77% during daytime activity and dropping to 50% during night-time resting. The HR mean and the maximum-minimum difference were lower during resting and at night and higher during grazing, walking, and daytime. They also increased with slope and Temperature Humidity Index (THI). This study indicates that this commercial biologging system is suitable for short-term monitoring of animals’ movement, behaviour and physiological responses to varying pasture and climatic conditions, offering insights for livestock management in alpine summer pastures.
... Following plenty of studies, HS assessment primarily depends on temperature humidity index (THI) calculation (Habeeb et al. 2018). Ruminants that kept in THI over 75 are considered under HS circumstances (Hahn et al. 2009). Alleviation of negative impacts of HS is beyond crucial for optimum reproductive competence. ...
Letrozole (LTZ) is an aromatase inhibitor that limits estrogen (E2) production and increases testosterone (T) levels. This research aimed to examine the impact of a single dose of LTZ on testicular hemodynamics, ejaculation time, and semen quality in goats under heat stress (HS). Therefore, Doppler examination and semen evaluation were performed on twelve mature bucks for two weeks (W-1, W-2) as pre-heat stress control during winter. Then during summer HS bucks were subjected to Doppler examination, semen evaluation, and hormonal analysis (T, E2, and LH) at 0 h. Afterward, bucks were assigned into two groups and subcutaneously injected with physiological saline (n = 6; CON) or LTZ (0.25 mg/kg BW; n = 6; LTZ). Both groups were subjected to Doppler scanning and hormonal analysis at 2, 4, 24, 48, 72, 96,144, and 168 h. Semen evaluation was performed at 48 and 168 h. The LTZ group showed increasing (P < 0.05) in semen volume, sperm motility, and viability and decreasing (P < 0.05) in ejaculation time and sperm abnormalities compared to CON group at 48 h. Additionally, T concentrations increased (P < 0.01) at 2, 24, and 48 h, E2 decreased (P < 0.01) from 2 to 48 h, and LH raised (P < 0.01) at 2 and 72 h in LTZ group compared to CON one. Doppler indices reduced (P < 0.05) at 96 h in LTZ group. semen pH and scrotal circumference were not affected by LTZ. In conclusion, LTZ administration shortened ejaculation time and enhanced semen quality in bucks during HS.
... The event was characterized by respective maximum TA of 41.4 and 42.3 °C on days 1 and 2; 37.4 and 36.1 °C on days 3 and 4, and 29.2 to 32.3 °C on days 5 to 7. Daily minimum TA was 24. 6 °C on days 1 and 2 and ranged between 18.7 and 21.5 °C on days 3 to 7. This event falls under the "Strong" category of heatwave using the heatwave schedule developed by Hahn et al. (2009). ...
Heat wave intensity, frequency and duration are increasing in many regions of the world, including locations where highly productive livestock are raised. There are animal health and welfare, as well as economic impacts from these events. In this study, the physiological responses of grain fed steers during a high heat load challenge through to recovery in climate controlled rooms (CCR) were intensively evaluated. Two cohorts of 12 Black Angus steers (BW, 615.4 ± 40.1 kg) sequentially underwent a simulated heatwave event that consisted of three phases in the CCR: PreChallenge (5 d duration, temperature humidity index (THI) range of 65 to 71), Challenge (7 d duration, THI 66 to 95 with diurnal cycling), and Recovery (5 d duration, THI 65 to 70). The Challenge period was modelled on a severe heat wave, characterised by three very hot days. Individual rumen temperature (RumT, °C) was collected every 10 min, and respiration rate (RR, breaths per minute), panting score (PS) and water usage (WU, L∙steer-1∙day-1) were obtained at multiple time points every day, by trained observers. Individual animal daily DMI was also determined. Morning (0700 h) rectal temperature was measured on d 3, 5, 7 to 13, 15 and 17. Not unexpectedly, RumT, RecT, RR and PS rose during Challenge, and fell rapidly as conditions eased. Conversely, DMI was reduced during Challenge. During the transition between PreChallenge and Challenge, there were abrupt increases in RumT, and RR. It was also very apparent that during Recovery the steers did not return to the baseline PreChallenge state. Compared to PreChallenge, Recovery was characterized by persistent lowered daily mean RumT (P = 0.0010), RecT (P = 0.0922), RR (P = 0.0257), PS (P ≤ 0.0001), and DMI (P ≤ 0.0001). These results provide evidence that these steers have undergone an allostatic response in response to high heat load, and the new adjusted physiological state post heat event may not be transient.
... Bucks in the present study were in normal conditions during the pre-heat stress periods (W1 and W2), while exposed to HS conditions from July to August. Based on Hahn et al. (2009) THI is categorised as normal if less than or equal to 74, alarming from 75 to 78, risky from 79 to 83 and emergent if equal or more than 84 as presented in Figure 3. ...
Heat stress (HS) disrupts testicular homeostasis because of oxidative stress. N‐acetylcysteine (NAC) is a thiol compound with antioxidants, anti‐inflammatory and anti‐apoptotic properties. As a sequel, this research aimed to assess the ameliorative effects of NAC supplementation on the reproductive performance of goat bucks kept under environmental HS. Primarily, Doppler examination as well as semen collection and evaluation were conducted on 12 mature bucks for 2 weeks (W) as pre‐heat stress control (W1 and W2) during winter (February 2023). The temperature–humidity index (THI) was 63.4–64.3 (winter season). Then during summer HS conditions (from the beginning of July till the end of August 2023) bucks were assessed before NAC supplementation (W0), afterwards they were arbitrarily assigned into two groups. The control group (CON; n = 6) received the basal diet while the NAC group ( n = 6) received the basal diet in addition to oral NAC daily for 7 weeks (W1–W7). The THI was 78.1–81.6 (summer season). Testicular blood flow parameters, serum concentration of nitric oxide (NO) and testosterone were measured. Additionally, total antioxidant capacity (TAC) and malondialdehyde (MDA) content in seminal plasma and semen quality parameters were evaluated. There were marked reductions ( p < 0.05) in the resistive index (RI; W1, W4 and W5), pulsatility index (PI; W2 and W4–W7), and systolic/diastolic ratio (S/D; W4–W7) in the NAC group compared to the CON group. Furthermore, testosterone and NO levels were higher ( p < 0.01 and p < 0.05, respectively) in the NAC group (W2, W3, W5 and W3–W5, respectively). Seminal plasma TAC increased ( p < 0.05) and MDA decreased ( p < 0.05) in the NAC group (W2, W4 and W5) compared to the CON group. Moreover, there were marked improvements ( p < 0.05) in semen quality parameters (mass motility, total motility, viability and normal morphology) in the NAC group. In conclusion, oral NAC supplementation could be used to enhance the reproductive performance of goat bucks during HS conditions which is supported by remarkable enhancement in testicular haemodynamics, NO, testosterone levels and semen quality parameters.
... With this information, two thermal comfort indices were estimated: (1) the temperature-humidity index; THI = (0.8 × AT) + ((RH/100) × (AT-14.4) + 46.4 (Hahn et al. 2009) and (2) THI adjusted for solar radiation and wind speed; THIa = THI + 4.51-(1.992 × WS) + (0.0068 × SR) (Mader et al. 2006). ...
... Thermal Humidity Index (THI) was calculated according to this equation using average values of relative humidity (RH) and average temperature (°C) using the formula described by Hahn et al. (2009) Estimate heritability and variance component by using the MTDFREML program of Boldman et al. (1995). The model used in this study: y= Xβ +Qg+Za+Wpe+e Where: y= a vector of productive traits (LTMY, TMY, DMY, LP and DP); β= a vector of fixed effects (season, year of calving, parity and farm); a= additive genetic effect; pe= permanent environmental), W= matrix relating records to permanent environmental (pe) impacts; e= residual effects and X, Z are incidence matrices relating observations to various effects of matrices relating records to genetic and fixed impacts. ...
The database was obtained from 4560 records multiple records were collected from 2000 to 2022 For a total of 2560 records for Sakha station and 2000 records for El-Qardah station of the Ministry Agriculture and land reclamation in Egypt, meteorological data were obtained from the central laboratory of Agricultural climate. The data was divided into two periods, the period from 2000 to 2010 (P1) and the period from 2011 to 2022 (P2). Thermal Humidity Index (THI) and season effect on productive traits (LTMY, TMY, LP and DP) were varied from significant (P<0.05) to highly significant (P<0.01) for both groups, except for the effect of THI on the DMY in P2 and season effect on DMY in P1, which were non-significant. Climate change in the period from 2011 to 2022 witnessed a rise in atmospheric temperature (AT), which was followed by an increase in relative humidity (RH) and atmospheric pressure (AP), as well as an increase in the value of THI especially in the summer season, which is hotter than the rest of the seasons, this had a negative effect on the productive traits. Estimates of permanent environmental variance for the second period for most traits were lower than additive genetic variance, it may indicate that sensitivity to heat stress is not specific to the cow but is hereditary. Heritability estimates are low to moderate for most milk production traits, which indicate the possibility of genetic improvement by selecting the most valuable cows for heritability or genetic selection of cows with improving the herd management.
... With this information, two thermal comfort indices were estimated: (1) the temperature-humidity index; THI = (0.8 × AT) + ((RH/100) × (AT-14.4) + 46.4 (Hahn et al. 2009) and (2) THI adjusted for solar radiation and wind speed; THIa = THI + 4.51-(1.992 × WS) + (0.0068 × SR) (Mader et al. 2006). ...
The study aimed to estimate economic losses associated with heat stress in the eight dairy production regions (DPR), defined by the Dairy Chilean Consortium, using two comfort thermal indices, namely, the temperature-humidity index (THI) and the THI adjusted for solar radiation and wind speed (THIa). Hourly records from 19 weather stations (Nov - Mar 2017–2022) were collected to estimate the comfort thermal indices. The economic impact was estimated considering a critical threshold of 65 for both indices and the effect of higher values on loss in milk yield, days open, culling rate, and deaths. There were differences in the number of hours above the threshold among DPRs, independent of the thermal index used (P < 0.01). The greatest values were observed in DPRs I, II, and VIII, which concentrate most dairy cows. Average losses in milk yield were between 2.0 and 6.4 times higher when THIa was used instead of THI, which also depends on the DPR (P < 0.01). These estimations coincide with those observed empirically by producers. The lowest average economic losses per cow during the summer season (5 seasons average) occurred in DPR VI (US 184.2) both using THIa. At the country level, economic losses fluctuate between US $ 29.0 and 108.4 million per summer season, depending on the comfort thermal index used. Finally, heat stress impacts negatively and significantly the Chilean dairy sector, which is highly dependent on the DPR.
... Temperature and humidity index (THI) -71.2 ± 0.88 (min -67, max -81). THI categories were defined by L.R. Hahn et al. (2009). ...
The temperature and humidity index (THI) is one of the most critical environmental factors, because it affects the body's thermoregulation and the overall productivity of goats. The study aimed to identify the relationship between the behavioural reactions of goats of different breeds and changes on the temperature and humidity index in the premises. The study used methods of time slices and recording of behavioural manifestations of goats. It was found that with a THI of 69-74%, the intensity of animal movement was high, but when the THI increased to 81%, activity sharply declined. After an extended stay in THI of 75-81%, goats find it quite challenging to restore average activity indicators. The animals were in the comfort zone (THI = 69-74%) and showed a moderate to weak approach to the feed table. With THI of 75-81%, goats showed interest; however, they did not consume feed. Animal rest positively correlates with such indicators as THI, r = from +0.40 (Saanen) to +0.49 (Alpine); movement in the pen, r = +0.62 and +0.66; approach to the feed table r = +0.32 and +0.31; and urination r = +0.16 and +0.12, respectively. A sharp increase in the rest frequency was detected at 76-81% THI. After normalising THI, animals also rested more frequently, which may be a consequence of heat stress. At the optimal level of THI (up to 74%), the frequency of goat rest decreased over a long period of time. A positive statistically insignificant correlation was established between THI and animal movement in the pen, r= from +0.19 (Saanen) to + 0.39 (Alpine). The movement of animals in the pen positively correlates with feed consumption, r = from +0.30 (Saanen) to +0.34 (Alpine), and negatively with the rumination process in animals, r = from -0.23 (Alpine) to -0.68 (Saanen). It was found that goats of the Saanen breed are more dependent on THI than the Alpine breed. The study's results should be considered when regulating the microclimate on premises for dairy goats and male goats
... One of these mechanisms is the increase in RR, which promotes heat evaporation through the increased exchange of breathed air. This leads to a reduction in the body's internal temperature, as evidenced by RT [74][75][76]. ...
The objective of this study was to evaluate the thermal comfort of Nelore cattle (Bos indicus) managed in silvopastoral and traditional systems associated with rumination behavior in a humid tropical environment in the Eastern Amazon, Brazil. The study was carried out on a rural property in Mojuí dos Campos, Pará, Brazil, during the transition period of the year, from June to July 2023. Over these two months, six consecutive data collection days were held. We selected 20 clinically healthy non-castrated male Nelore cattle, aged between 18 and 20 months, with an average weight of 250 kg and body condition score of 3.5 (1–5). These animals were randomly divided into two groups: traditional system (TS) and silvopastoral system (SS). The physiological variables evaluated included RR, RT and BST. The variables were analyzed using the linear mixed model. For agrometeorological variables, higher values were observed between 10:00 a.m. (33 °C) and 6:00 p.m. (30 °C), with the highest temperature observed at 4:00 p.m. (40 °C). The RR showed interactions (p = 0.0214) between systems and times; in general, higher RR were obtained in the Traditional. The animals’ RT showed no significant difference (p < 0.05) between the production systems, but there was a statistically significant difference in relation to the time of collection (p < 0.0001). In the BGHI, it was possible to observe that there was mild stress in the period from 22:00 at night to 6:00 in the morning and moderate stress in the period of greatest increase in temperature, from 10:00 in the morning to 18:00 at night. BST showed no statistical difference between the regions studied or between the SP (35.6 °C) and TS (36.25 °C) systems. RT in the TS showed a positive correlation with AT (r = 0.31507; p = 0.0477). RT in the SP showed a positive correlation with THI (r = 35583; p = 0.0242). On the other hand, RT in the SP (r = 0.42873; p = 0.0058) and ST (r = 0.51015; p = 0.0008) showed a positive correlation with BGHI. RR in the TS showed a positive correlation with BGHI (r = 0.44908; p = 0.0037). The greatest amounts of rumination were carried out by animals in the SP system, generally ruminating lying down (p < 0.05). With regard to rumination behavior in the morning and afternoon, there were higher numbers of WS and LD in the TS (p > 0.05). Most of the time, the cattle were LD during the morning and afternoon shifts, and at night and dawn they were WS in the TS. Therefore, the SP offers more thermal comfort advantages compared to the TS system.
... The THI has been demonstrated to be a valuable instrument for assessing the relationship between livestock productivity and climate (Ravagnolo et al., 2000;Dikmen & Hansen, 2009). The measure is determined by considering the air temperature and relative humidity, with varying degrees of importance assigned to various classes (Hahn et al., 2009). It serves as the indication of combined external factors that influence the deviation of body temperature from its desired level (Tao & Xin, 2003). ...
... THI criteria, such as the Livestock Meteorological Safety Index (NOAA, 1976), have been used for a long time by US extension agencies to provide livestock farmers with information about potential heat stress caused by the environment (Eirich et al., 2015). According to Hahn et al. (2009), the stress levels classified as THI based for ruminants (cattle, sheep, and goats) are as follows: normal ≤ 74; moderate = 75-78; severe = 79-83; and extremely severe (emergency) ≥ 84. ...
... Heat stress is affected by climate, THI formulation, as well as HS management strategies, which detect micro-climates (Lallo et al., 2018;Dikmen & Hansen, 2009), and the breed of the animal, how well adopted it is to the climate, as well as its physiological condition (Dikmen & Hansen, 2009;Tao & Xin, 2003;Ajakaiyeet al., 2011). Based on the studies conducted by (Lallo et al., 2018;Hahn et al., 2009) our findings indicate that ruminants rearing in Bangladesh faced HS ranging from severe to extremely severe levels ( Table 1). Notably, there were yearly variations in THI values for ruminants, which varied from 77 to 86. ...
The production of ruminant livestock is greatly impacted by climate change, as it is anticipated to jeopardise food security due to the increasing heat stress experienced by the animals, which can be measured using the Temperature Humidity Index (THI). The objective of our study was to analyze climatic patterns, identify influential variables and evaluate heat stress episodes through the utilization of the THI to establish a rearing system for ruminants in Bangladesh. The THI value was determined by analyzing meteorological station data spanning from 1995 to 2022 across various climatic zones in Bangladesh. The Mann–Kendall evaluation was used to analyze the THI patterns throughout the study. Our findings indicated that heat stress problems are expected to occur in Bangladesh when THI for ruminant rearing exceeds 74, particularly from February to December. The severity of heat stress in THIruminant 71–90 varied significantly, ranging from normal to extremely severe. We observed that June (90) was the hottest month in the west central region, while January (71) was the coldest in the northwest area. When examining the impact of climatic factors on the THI, we found that air temperature has the highest influence, while relative humidity had the second-highest influence on THI in all areas of Bangladesh. Sunlight length and wind speed influenced the yearly THI marginally but not seasonally. Our findings highlighted a seasonal threat associated with heat stress in the climatic conditions of Bangladesh. It is essential to identify heat stress in ruminants, especially considering the continuing global warming issue. Our results recommend the implementation of heat stress mitigation strategies for ruminant farmers in Bangladesh.
