THI Values Research Articles

Meta-analysis of endophyte-infected tall fescue effects on cattle growth rates.

The objective of this study was to quantitatively summarize literature reporting endophyte-infected (Neotyphodium coenophialum) tall fescue (Festuca arundinacea) effects on cattle ADG. This meta-analysis evaluated endophyte infection level, climate, and forage yield using a literature dataset of 138 treatments from 20 articles. Three infection level measurements were tested: endophyte infection as a percentage of infected tillers (E%); ergovaline concentration in ppb ([E]); and total ergot alkaloid concentration ([TEA]). Three types of climate variables were used: base values (temperature, humidity, and relative humidity), climate indices (heat index and temperature-heat index [THI]), and novel climate variables accounting for duration of climate effects. Mixed effect models, weighted by 1/SEM, including a random effect of study were built for each factorial combination of measurement method and climate variable group. Because many studies were missing SEM, two datasets were used: one containing only data with SEM reported and one that also included missing-SEM data. For the complete-SEM dataset (CSD), models were weighted by 1/SEM. In the missing-SEM dataset (MSD) the mean reported 1/SEM was assigned as the weight for all missing SEM treatments. Although 18 initial models were created (2 × 3 × 3 factorial approach), the backward stepwise derivation resulted in models that included only endophyte infection level, suggesting a negative relationship between infection level and ADG. The CSD models predicted ADG to decrease 39 and 33 g/d with each increase of 100 ppb of [TEA] and [E], and by 39 g/d for each increase of 10% E%. In the MSD dataset, predicted ADG decreased by 39 and 33 g/d with each increase of 100 ppb of [TEA] and [E], and by 47 g/d for each increase of 10% E%. All relationships reported had P < 0.05. After visual inspection of the data, piecewise regression was used to identify an infection threshold (IT) of 60 ppb [E] and 11 E%, where the effect of infection level was constant on either side of the IT. The ADG was 40% and 49% greater for infection levels below the IT for [E] and E%, respectively. Across THI values in the analysis, ADG decreases ranged from 11.2% to 45.0% for cattle grazing endophyte-infected tall fescue compared to non-ergot alkaloid endophyte infected tall fescue. Pasture E%, [E], and [TEA] have a negative relationship with ADG in growing cattle, and increasing temperature decreases ADG when infection level is greater than the IT.

Effects of the season on physiological and endocrine traits and on HSP70 in Saanen goats under Mediterranean climate conditions

This study was conducted to determine the impact of heat stress on some physiological and endocrine traits in Saanen goats raised under Mediterranean climate conditions. The effects of thermal stress on heart rate (HR), respiration rate (RR) and rectal temperature (RT) on plasma total trii-odothyronine (T3), thyroxine (T4), Cortisol (C), and HSP70 concentrations were evaluated on twenty two Saanen goats of different ages in the second week of April 2013, July 2013, October 2013 and January 2014. Climatic data such as temperature (°C) and relative humidity (%) were recorded from Spring 2013 to Winter 2014. Live body and BCS values were also recorded during this period. The physiological parameters above were measured twice on each experiment day (morning and afternoon) in all seasons. Blood samples were collected in each afternoon of the experiment day to analyze T3, T4 C, and HSP70. All data were analyzed. According to the values of rectal temperature (RT), it was estimated that the goats were under extreme heat stress only in the summer season. The heart rate (HR) values in the winter season for morning and noon periods were found statistically significant (p &lt; 0.05). The average respiratory rate (RR) in the spring season was found significantly lower. On the other hand, the RR for the noon period in the summer was higher than in the fall and winter seasons (p &lt; 0.05). There was a significant difference (p &lt; 0.05) between summer and fall seasons for C values. The highest value (96.62 ng/ml) was obtained in spring, whereas the lowest (60.58 ng/ml) in the fall. T3 levels in the fall and winter were found to be statistically significant (p &lt; 0.05). They were the highest in the winter and spring, and the lowest in fall. T4 and T4/T3 levels in the winter were found to be statistically higher than in other seasons (p &lt; 0.05). The lowest value for T4 was found in the fall and for T4/T3 in summer. Mean HSP70 value in spring was found to be statistically low (p &lt; 0.05). The changes in THI values in different seasons, particularly between mornings and afternoons, indicated that thermal stress was evident, and that the animals became resistant to it eventually. The fluctuations of the C, T3, T4 and HSP70 values were indicators of the animals’ reaction to thermal stress. The THI values in spring, which were between 16 and 18 THI, may be considered within the ideal comfort zone for goats. It was observed that Saanen goats were able to adapt to seasonal weather changes in the environmental conditions of the region....

EFFECT OF SELENIUM YEAST AND/OR VITAMIN E SUPPLEMENTED RATIONS ON SOME PHYSIOLOGICAL RESPONSES OF POST-LAMBING OSSIMI EWES UNDER TWO DIFFERENT HOUSING SYSTEMS

This study was carried out to investigate the effect selenium yeast and/or vitamin E supplemented rations under two different housing types on reproductive performance of post-lambing Ossimi ewes. Along thirty days pre-lambing, eighty pregnant Ossimi ewes averaged 40.38±0.93 and 39.49±1.12kg live body weight were housed under two different housing systems, the first (semi open with concrete floor and roofed with west-east direction, 1st H) and the second (fully shaded roofed with single asbestos sheets and was topped with rice straw bales and natural earthen ground with north-south direction, 2nd H) housing type, respectively. Ewes were divided into two equal groups (40 ewes each) according to age, body weight and parity. Each group was settled in one of the housing type and randomly divided into four subgroups (ten ewes per each); group A was kept as a control and was fed the basal diet consist of roughage (rice straw) and concentrate mixture, group B selenium yeast (SY) was fed the basal diet supplemented with 0.3 mg of SY per kg of diet, group C vitamin E (VE) received the same basal diet supplemented with 40 mg VE per kg of diet and group D fed the basal diet supplemented with both SY and VE. Results reported that semi open type house (1stH) had significantly higher (P<0.01) Air temperature (AT) at morning and afternoon than that in fully shaded type house (2nd H). Daily average AT was lowest value (24.82 °C) in 2nd H than 1stH (30.90 °C). Relative humidity (RH) was significantly higher at morning than afternoon in two housing types. THI values ranged from 61.20 to 64.17and 87.10 to 91.34 in the morning and afternoon, respectively in the two hosing systems. However, the THI average, at morning and the afternoon values in 2nd house was lower (P< 0.05) THI than that of semi open type (1stH). The average values of thermo-regulatory parameters of ewes post-lambing in the morning and afternoon as affected by SE and VE supplemented rations under two different housing systems presented were significantly decreased in SY+VE group followed by SY and VE groups compared to control group in the morning and afternoon in two different housing types. Present data showed significantly (P<0.01) higher in most of hematological parameters (Hgb, RBCs, HCT, PLT, WBCs and differential leucocyte count) under the conditions of subsistence in the 2nd H compared with 1st H. antioxidant enzymes levels showed higher values in SY+VE group compared with the level observed another groups specially control group. Treated ewes by both SY and VE reached to first estrus post-lambing at earlier time and recorded heavier body weight and shorter estrus duration than the other ewes in first and second house. There was significant (P<0.01) increased in mean serum P4 concentration in all treated groups compared with control group at all time under two hosing systems, indicating the presence of functional corpus luteum in some of the animals. Also, that administration of SY plus VE gave significantly (P<0.01) higher P4 and E2 concentrations at day 8, 12, 16, 20 and 24 post-lambing. It could be concluded that SY and/or VE supplemented rations can improve physiological responses post-lambing of ewes under different housing systems.

Impact of Dietary Moringa Oleifera Leaves Supplementation on Semen Characteristics, Oxidative Stress, Physiological Response and Blood Parameters of Heat Stressed Buffalo Bulls

This study aimed to evaluate dietary supplementation of Moringa oleifera leaves (MOL) on semen quality, oxidative stress, thermal regulation and health status of heat stressed buffalo bulls. Eighteen sexually mature Egyptian buffalo bulls were divided into three groups, 6 in each. Bulls in G1 were fed ration composed of concentrate fed mixture (CFM), berseem hay and rice straw (control). Bulls in G2 and G3 were fed the same CFM supplemented with MOL at levels of 4 and 8% of CFM, respectively for one month pre-semen collection and 4 months as semen collection period. Semen was collected twice weekly and evaluated for percentages of individual motility (IM), livability (SL), abnormality (SA) and damaged acrosome (DA) of sperm cells. Response of spermatozoa to hypo-osmotic test (percentage of curled spermatozoa) at 50 mOsm/l for 30 min was also recorded. Rectal (RT) and skin (ST) temperatures, respiration rate (RR) and pulse rate (PR) were recorded. Blood samples were taken pre-treatment and during 1st, 2nd, 3rd and 4th months of semen collection to determine hemoglobin concentration (Hb), packed cell volume (PCV%), count of red (RBCs) and white (WBCs) blood cells. Concentration of total proteins (TP), albumin (AL), globulin (GL), glucose (GLU), triglycerides (TG), total cholesterol (TC), high-density lipoprotein (HDL), low-density lipoprotein (LDL), urea, uric acid, creatinine (Cr) and testosterone, as well activity of AST, ALT, superoxide dismutase (SOD), catalase and glutathione (GSH) were determined in blood serum. Concentration of TG and TC, and activity of AST, ALT, SOD, catalase and GSH were estimated also in seminal plasma. Results showed that RT and ST, RR and PR decreased (P<0.05) in G3 than in G2 and G1. Each of RT and ST, RR and PR increased (P<0.05) up to 3rd collection month, then decreased at the 4th collection month in association with THI values. Percentage of IM, SL, SA, CT and DA were improved (P<0.05) in G2 and G3 as compared to G1, being the best (P<0.05) in G3. All previous parameters were improved (P<0.05) by advancing collection month. Both TC and TG in seminal plasma decreased (P<0.05) in G3 as compared to G1 and G2. Activity of AST and ALT decreased (P<0.05), while catalase, GSH and SOD activities increased (P<0.05) in seminal plasma of G2 and G3 as compared to G1. Each of TC, ALT, catalase, GSH and SOD in seminal plasma increased (P<0.05), while TG decreased (P<0.05) by advancing collection month, while AST was not affected. Serum testosterone con­centration was higher (P<0.05) in G2 and G3 than in G1, being the highest in G3. Each of PCV, Hb and RBCs were higher (P<0.05) in G2 and G3 than in G1, being the highest in G3, while WBCs showed (P<0.05) an opposite trend (P<0.05). Each of Hb, RBCs and WBCs increased (P<0.05) one month after treatment, then Hb and RBC increased (P<0.05), while PCV and WBCs decreased (P<0.05) at the 4th collection month. Serum TP, AL and GLU increased (P<0.05) in G3 as compared to G1 and G2, while GL was not affected by treatment. By advancing collection month, concentration of TP, AL, GL and glucose showed gradual increase (P<0.05). Concentration of TG and TC reduced (P<0.05) in G2 and G3, while HDL increased (P<0.05) in G3 as compared to G1. However, LDL was not affected by treatment. Concentration of TG decreased (P<0.05), while HDL increased (P<0.05) by advancing collection month. Concentration of TC and LDL showed fluctuated trend of change at different collection months (P<0.05). Serum urea decreased (P<0.05) in G3, while uric acid, creatinine, AST and ALT decreased (P<0.05) in G2 and G3 as compared to G1. Urea and uric acid decreased (P<0.05) during one month before semen collection and at the 3rd collection month, respectively. However, Cr, AST and ALT decreased (P<0.05) by advancing collection month. Catalase, GSH and SOD increased (P<0.05) in G2 and G3, being the highest in G3. All antioxidant enzymes increased (P<0.05) by advancing collection month, being at higher rate for SOD, followed by GSH and the lowest for catalase during month pre-treatment. The current study can conclude that, moringa oleifera leaves could be used as feed additive to help farmers for sustainable development of breeding bulls. Results of this study recommended that daily adding 240 g moringa oleifera leaves per buffalo bull for one month pre-semen collection or at a level of 8% of concentrate feed mixture in diets of buffalo bulls can improve quality and production of semen without any adverse effects on health status under hot climatic conditions in Egypt.

Assessment of microclimate and gaseous pollutants in dairy and pig sheds in an organised farm

Intensive livestock production is one of the major sources of atmospheric emissions of greenhouse gases. The microclimate of livestock sheds also influences the productivity and shelf-life of livestock products. The present study assessed the gaseous pollutants and microclimate in dairy and pig sheds in an organised farm. Three types of livestock buildings, viz. dairy cow, pig fattener sty and farrowing pen were selected for the study purpose. Microclimatic data was recorded daily during rainy, winter and summer seasons periodically. Indoor gaseous pollutants, viz. carbon dioxide (CO2), ammonia (NH3) and methane (CH4) were recorded using multi gas monitor. The assessed THI values were higher than the ideal value of 72 in all the livestock sheds irrespective of the seasons. With regards to gaseous pollutants, CO2 and NH3 emissions were less in the afternoon when compared to morning sessions in contrast to CH4 which was higher in afternoon sessions in all the sheds. All the three gaseous pollutants were within the recommended threshold limit level.

IMPACT OF PROBIOTICS SUPPLEMENTATION ON SOME PRODUCTIVE PERFORMANCE, DIGESTIBILITY COEFFICIENT AND PHSIOLOGICAL RESPONCES OF BEEF BULLS UNDER HEAT STRESS CONDATIONS

This experiment was carried out in the New valley Governorate during May tell September 2016 in privet farm. Twelve crossbreed beef bulls average 252.98 to 255.66 kg body weight (BW) were used in this study. Animals were divided randomly into three groups (4 animal/group). The first group (G1) served as control. The second and the third groups (G2 and G3) were supplemented with commercial probiotics at a rate of 0.5 to 1.00 gm/ kg of concentrate mixture, respectively. The animals were fed individually on concentrate fed mixture, berseem hay and wheat straw to cover the requirement of DM and TDN for average body weight and daily gain of beef. Experimental period lasted 150 days. Digestibility coefficients of different nutrients and nutritive values (TDN and DCP %) of the experimental rations were calculated. Blood samples were collected from each animal at day 0, 75 and 150 of experiment period. Serum samples of all animals were assayed for determenation of triiodothyronine (T3), thyroxine (T4), total protein, albumin, glucose, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations. Body weight (BW) of animals was recorded at the beginning of experimental period and monthly thereafter. Total gain, daily gain and daily average feed intake were calculated. Thus, value of feed efficiency was calculated. Monthly average of ambient temperature, relative humidity and temperature humidity index were calculated during the experimental period. Monthly of THI values in the present study during experimental period from May to September recorded more than 74. Thus, animal suffered from heat stress. Also, the present results indicated that supplementation of probiotics in the diet of beef bulls led to positive effect on rectal temperature and respiration rate in G3 and G2 compared to control group G1. Values of rectal temperature and respiration rate during experimental period were decreased in G2 and G3 as a result of supplementation of probiotics in comparison with G1, but the differences were not significant. The present results indicated beneficial effect of feeding beef bulls on diets supplemented with probiotics to eliminate heat stress. Digestibility coefficients of different nutrients improved in treatments. The best values of digestibility coefficients of nutrients were recorded in G3 followed by G2 and the lowest values were recorded in control group (G1). Also, supplementation of probiotics led to significant (P<0.05) effect on total digestible nutrients (TDN) and digestible crude protein (DCP) in G3 in comparison with G2 and G1. Final BW of beef bulls and daily gains recorded the higher value in G3 followed by G2 and the lower value of was recorded in G1. At the same time, feed intake and feed efficiencies in G3 recorded higher values in comparison with G2 and G1. The results indicated that the mean concentrations of total protein, albumin, glucose, AST, ALT, T3 and T4 were increased in G2 and G3 in comparison with G1. The present results illustrated that improvement of net profit as a result of supplementation probiotics in G2 and G3. From the present results it can be concluded that supplementation of probiotics in the diet of beef bulls improved growth performance, nutrient digestibility and physiological response under heat stress conditions. Such improvement is due to a positive effect on blood metabolites parameters as physiological responses

Influence of some environmental factors on maize productivity in Osun state, Nigeria

Temperature, humidity and direction of the prevailing wind are parts of significant environmental factors, which have greater impact on crop productivity, especially with the recent global climate change. These were researched into on maize seeds planted at three different furrow orientations on the field; Or. 900, Or. 600 and Or. 300 to direction of the prevailing wind on the same plot of land at three replicates A, B and C each. Temperature and humidity were measured at 8.00hr, 10.00hr for morning; 14.00h and 16.00h for afternoon each day. Temperature-Humidity Index-THI was calculated using THI equation. Leaf development was measured in terms of broadness, stem girth, length and number of leaves. Harvest Index, HI and Leaf Area Index, LAI were also calculated. The result shows that at significant level (p &lt; 0.05), effect of Or. was observed on THI values in the afternoon period, but in the morning, significant (p &gt; 0.05) effect of orientation on THI was not observed. The Or. 900 had highest HI of maize and better growth. The LAI values show that Or. 900 had higher LAI (0.775), than that of Or. 600 of value (0.770), between 40th and 70th days. It was found out that orientation of furrow of maize crops to direction of the prevailing is a function of the environmental parameters such as temperature, humidity, and the closer the orientation of furrow slice for crop leaves is towards the 900 wind direction, the better its growth and yield. Key Words: Crop productivity, Leaf Area Index, Temperature-Humidity Index, orientation, Osun State

Changes in thermal discomfort indices in Romania and their connections with large-scale mechanisms

We analysed changes in variability characteristics for 2 indices quantifying winter (WCT: wind chill equivalent temperature chart index) and summer (THI: temperaturehumidity index) thermal stresses at a high spatial resolution across Romania for the period 1962� 2010. The linear trends, and shifts in the mean and main modes of variability were examined using nonpara- metric tests (Mann-Kendall and Pettitt) and empirical orthogonal function (EOF) analysis. The physical mechanisms responsible for the identified characteristics of variability were examined through canonical correlation analysis (CCA). The results showed a significant upward trend for both indices over the entire country, except for some areas for WCT, with a significant upward shift around the year 1987 for winter and 1985 for summer. A strong increase in the frequency of extremely high THI values was revealed, indicating an increased risk to human health during summers in Romania after 1985. However, the upward trend in WCT would indicate a decreased risk of human health during winters in Romania after 1987. The main large-scale mechanism responsible for the spatial and temporal behaviour of the 2 stress indices was given by the first CCA pair, showing that the increasing trend was mainly explained by the increasing trend in the temperature at 850 hPa covering Romania simultaneously with an increasing trend in zonal circu- lation (WCT) and an increasing trend in specific humidity at 700 hPa (THI). On a decadal/multi- decadal time scale, the variations in the 2 indices are modulated by the North Atlantic Oscillation (winter) and the Atlantic Multidecadal Oscillation (summer).

Effect of altitude and season on dry matter intake, THI and growth rate in mithun

A comparative study on effect of altitude and season on dry matter intake, THI and growth rate on growth performance and nutrient utilization in mithun calves was carried out at Medziphema farm (300 MSL) and Porba farm (2,100 MSL), Nagaland, India. The mithuns of either sex were selected and fed in confined condition. DM intake differed significantly during the seasons and between the altitudes. Growth rate of 521 g/day and 524 g/day were obtained during the experiment during pre- monsoon season which were nonsignificant. Growth rate of 643 g/ day and 548 g/day were obtained during winter at Medziphema and Porba farms, which were showing nonsignificant difference between body weights and at both altitudes. Feed conversion efficiency were nonsignificant between the altitudes and seasons. THI values differed significantly between the altitude and seasons. It was concluded that mithuns can be reared at both the altitudes without any significant difference in body weight.

Effects of air temperature and humidity on average daily gain in feedlot cattle of different genotypes

Abstract. The purpose of this study was to observe Holstein, Brown Swiss, Simmental and cross breed Anatolian Black genotypes fattened in feedlot regarding their ability to tolerate temperature and humidity and to compare Temperature Humidity Index types under climatic conditions of Şanlıurfa province in Turkey. Data obtained from a commercial farm composed of 70 594 test day records of 11 117 cattle (6 513 Holstein, 3 546 Brown Swiss, 838 Simmental and 220 Anatolian Black Crosses). Meteorological data were provided from nearest weather station located 9.04 km away from feedlot area. THI values were calculated by using daily maximum, minimum and average air temperature and, humidity values according to three different combinations for each animal. Analysis were based on such a model that includes effects of year, sex, age, season, days on feed, beginning stage of fattening and several types of THI. Results showed that, Simmental and Anatolian Black genotypes were slightly more tolerant to heat stress compared to Holstein and Brown Swiss. In addition, Anatolian Black genotype was more sensitive to cold stress when compared to other genotypes. Different breakpoint values for stress and comfort zone intervals were obtained when different combinations of temperature and humidity variable (maximum or minimum) were used in THI formula.

Forecasting Heat Stress in Dairy Cattle in Selected Barn Zones with the Help of Thi and Thiadj Indexes / Prognozowanie Stresu Cieplnego U Bydła Mlecznego W Wybranych Strefach Obory Za Pomocą Wskaźników Thi I Thiadj

Abstract The paper presents the influence of temperature, relative air humidity, air movement velocity and solar radiation on forecasting the risk of heat stress in dairy cows in a free-stall barn during hot weather seasons. THI and adjusted THI indexes were calculated for the periods in which the air temperature exceeded 28°C in the barn, and when it reached 25°C. Based on the THI values obtained during the heat, which ranged from 63 to 83, the occurrence of heat stress in cattle was stated. Heat stress also caused a decrease in milk yield, from about 22 kg to about 18 kg in the technological group. The calculated THIadj values (83 to 90), taking into account the solar radiation and air movement velocity, indicated also the occurrence of health-threatening conditions for cattle. On the fourth day of heat the maximum daily value of THI in the first measurement point was 83 with THIadj of 90, while in the second point THI was 82 and THIadj was 87. This indicated the occurrence of significant differences in microclimatic conditions in the occupied zone of the same technological group. The influence of investigated microclimate factors on the formation of THIadj in the researched zone of the barn was stated. No proper method of its determination was also stated. The analysis of the impact of air movement velocity on THIadj value (P&lt;0.05) and the solar radiation (P&lt;0.05) demonstrated the importance of these parameters in forecasting heat stress in cows in the barn.

Thermal comfort estimation in relation to different orientation in mountainous regions in Greece by using artificial neural networks

This study focuses on the estimation of thermal comfort conditions in a high alt. site (1455 m) in Apodotia (MA), Greece, by using the MLP neural network model. This estimation is based on the air temperature (t) and relative humidity (f) data of the middle (1078-1163 m) and of the low altitude levels (816-862 m) in relation to different orientations in MA. Also, the MLP model was applied on the top of the Mt. Koromilies (alt. 1350 m) for the estimation of thermal comfort conditions based on the t and f of a site (alt. 797 m) on the northern slope of Mt. Parnassos. In both MA and Parnassos regions the “Cold” and “Comfortable” classes of thermal comfort prevailed. The MLP model provided more satisfactory estimations of the THI values from the t and f of the middle alt. level compared to the respective estimations from the low alt. level. The model provides less accurate estimations of the THI values at 1455 m alt., in the case of sites located near watery surfaces in MA. The application of the MLP model in the case of the Mt. Koromilies, in Parnassos indicated more accurate estimations of the THI values compared to the respective estimations in Apodotia.

A comparative study of human thermal comfort conditions in two mountainous regions in Greece during summer

Human thermal comfort conditions were determined in two mountainous regions of Greece, Gerania mountains (MG) in east continental Greece, and mountainous Nafpaktia (MN) in west continental Greece. Both regions are unexploited with considerable tourist potential. Four sites in each study region were selected on the basis of different altitude. Air temperature and humidity, 1.5 m above ground surface, were recorded simultaneously every 15 minutes by sensors with dataloggers in selected sites between 23 June and 28 August 2007. Data of the above parameters were used for the calculation of the thermohygrometric index from which thermal comfort conditions were evaluated. Also, an artificial neural network model, was applied for the THI values evaluation at the highest examined altitudes based on the respective values of the lowest examined altitudes in both MG and MN. Results showed that from 09:00 to 20:00 h, MN was found to be more suitable, in relation to MG, for tourist and recreation activities at altitudes of 1338 m. At lower altitudes, both study regions could be proposed in an equal basis for the above activities during summer. Also, for the same period, thermal comfort conditions at the highest examined altitudes of MN and MG can accurately be predicted using artificial neural network models on the basis of those at lowest examined altitudes. From 21:00 to 08:00 h, MN can be considered clearly as a better tourist destination than MG.

The influence of THI values at different periods of lactation on milk quality and characteristics of lactation curve

The experiment included 90 cows. Cows were chosen according to the time of calving, so that the first third of lactation occurred during the summer in 30 cows (G1), the second third of lactation occurred during the summer in 30 cows (G2), and in the last 30 cows the last third of lactation was in summer period (G3). The value of THI was between 72 and 82, which indicates the existence of the moderate intensity of heat stress. Heat stress does not damage the milk yield, milk fat and protein percentage on the level of the whole lactation, regardless of the lactation period in which the cows were exposed to stress. There was no correlation between THI and milk yield and quality at the level of the whole lactation. Heat stress did not show a significant effect on the parameters of lactation curve, except the peak of yield, which occurred later in cows exposed to heat stress. Increased value of THI showed nonsignificant effect on yield and quality of milk in the first third of lactation. In the middle and at the end of lactation THI was in a significant negative correlation with the yield and quality of milk. Our study showed a significantly lower heat-induced milk yield, milk fat and protein percent in the middle and at the end of lactation.

The Effects of Skin Pigmentation on Physiological Factors of Thermoregulation and Grazing Behaviour of Dairy Goats in a Hot and Humid Climate

The aim of this study was to understand the effects of skin pigmentation on physiological parameters of thermoregulation and grazing behaviour of dairy goats in a hot and humid climate. The study used 26 crossbred Saanen yearling goats (95% Saanen+5% Local Hair Breed). The animals were raised at semi-intensive private farms in Adana (36 59' N, 35 18'E). Groups were selected 2 d before the start of observations. Goats were categorized as predominantly pigmented (P) skin and unpigmented (UP) skin. All observations and measurements were collected on grassland during the grazing period of June and July 2007 (60 d). Air temperature and relative humidity were recorded at 10 min intervals by a portable data logger. The physiological data (rectal temperature, respiration and pulse rate, and skin temperatures from head and udder) were recorded twice weekly in the morning (07:00-08:00); at midday (13:00-14:00); and in the evening (18:00-19:00). Additionally, the activity of the animals was observed and classified (eating, ruminating, drinking, standing, walking, lying) for 12 h during the day twice weekly, using a portable camera system linked directly to a computer. Panting behaviour was also observed. According to the THI values, the experimental goats were subjected to stressful conditions. The pigmented goats had significantly lower rectal temperatures (39.68 vs. 29.89°C), pulse rate (74.08 vs. 84.10 beat/min) and respiration rate (65.65 vs. 88.23 breath/min.) compared with unpigmented goats at midday when the THI exceeded 92. The rectal, head and udder temperatures, pulse and respiration rates of the non-pigmented group exceeded 40°C, 37°C, 37.5°C, 84 beats/min and 78 breaths/min, respectively. Higher activity was observed among pigmented compared with unpigmented goats. Unpigmented goats grazed (4.3 vs. 5.6 h), ruminated (2.0 vs. 2.4 h), and stood (0.8 vs. 1.2 h) less, but lay down (2.2 vs. 1.8 h) more than pigmented goats. The data obtained in this experiment support the hypothesis that unpigmented goats are more adversely affected by climatic stress, likely due to their decreased activity and increased water consumption, as demonstrated by previous studies.

Milk production and physiological traits of ewes and goats housed indoor or grazing at different daily timing in summer

During a 6 week trial in summer, 3 homogeneous groups, each consisting of 5 Comisana ewes and 5 Rossa Mediterranea goats, grazed watered forage resources during day (D) or night (N), or were housed indoor and supplied with mowed (H). Maximum THI peaked at 94 at the end of July, and herbage was almost constantly higher of 80. Milk yield was higher in N than in D and H goats, whereas N ewes produced more milk than H group, but their milk yield was higher than D ewes only in the period with the highest THI values. The lower urea in N goat milk, and the higher casein in N ewe milk, seem to indicate a better efficiency in dietary nitrogen utilization of night grazing animals. N ewes showed lower SCC in milk, and higher incidence of clotting milk samples, in comparison to other ewes. N goats and ewes showed lower rectal temperature and pulse rate in the afternoon and, among metabolic parameters, higher hematic level of sodium. Night grazing was confirmed to be a management practice for increasing heat tolerance, to which goats appeared to be more sensitive in terms of milk yield.

Seasonal trend of some parameters of the milk quality payment for Parmigiano-Reggiano cheese

The study was carried out during 4 years (2002∏2005) on 85587 bulk milk samples from the evening and the morning milking of 1340 dairy herds subdivided in plain, hill and mountain. All the parameters were influenced by year, season and year*season interaction. Titratable acidity showed higher values in autumn (3.28 °SH/50ml) and lower in summer (3.22). Somatic cell count was lower in winter and higher in summer. The calculated casein values, were higher in autumn (2.54 g/100g) and lower in spring (2.42). Fat content values were higher in autumn (3.67 g/100g) and lower in spring and summer (3.47-3.46). During summer the quality of the milk had a general worsening. Such a worsening was more evident during summer of the year 2003, characterised by THI values higher than those of years 2002, 2004 and 2005.

Computer Simulation Assessment of the Thermal Microenvironment of Growing Pigs Under Summer Conditions

The effects of outside climatic conditions on the thermal microenvironment inside a building for growing pigs (50 kg mean) were studied using a 30-year period set of hourly real weather data from the Athenian region. Transient computer simulation allowed hourly prediction of air temperature and relative humidity inside the swine unit for each year. Under Greek summer conditions (May to September) pigs are subjected to heat stress of considerable duration and intensity due to temperature, while few problems due to relative humidity occur. Furthermore, inside THI values exceeded 85 only a few hours, therefore THI cannot effectively be used as a heatstress index.