Tag Archives: heat stress

1047-1059 Xh. Bytyçi, N. Hasanaj, M. Zeqiri, F.C. Ajazi, S. Makolli and S. Aliu
Seasonal and farm-specific variations in milk fat percentage: impact on quality and economic performance in dairy production
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Seasonal and farm-specific variations in milk fat percentage: impact on quality and economic performance in dairy production

Xh. Bytyçi¹, N. Hasanaj²*, M. Zeqiri¹, F.C. Ajazi¹, S. Makolli¹ and S. Aliu¹

¹Department of Food Sciences and Biotechnology, University for Business and Technology, Kalabria, XK10000 Prishtina, Kosovo
²Department of Food Science, University “Haxhi Zeka” KLA Str., XK30000 Peja, Kosovo
Correspondence: xhavit.bytyci@ubt-uni.net

Abstract:

This study investigated the seasonal dynamics of milk fat percentage and its economic implications across 83 small-scale dairy farms in the Istog region of Kosovo over one year. A total of 1,616 valid raw milk samples were collected and analyzed twice monthly per farm using the Gerber method. The average annual milk fat content was 3.75%, ranging from 2.90% to 4.00%. Statistically significant monthly differences were observed (Friedman test, p < 0.001), with May showing the highest average fat percentage (3.807 ± 0.133%) and August the lowest (3.682 ± 0.220%). While Spearman’s correlation did not indicate a significant relationship between ambient temperature and milk fat percentage, seasonal comparisons revealed significantly higher fat values in spring than in winter (p = 0.009, rrb = 0.543). Farm-level analysis showed considerable variation, with fat content ranging from 3.35% to 3.92%, likely reflecting differences in general management practices and potential variations in breed and feeding. An economic model based on €0.075 per 1% fat per liter of milk and an annual production of 36,000 liters per farm revealed income disparities of up to €1,539 per year due to fat percentage differences. These findings underscore the importance of improving farm-level practices and implementing seasonal management strategies to stabilize milk fat content and reduce economic losses, particularly during warmer months when fat levels tend to decline. Future research should further investigate the specific effects of cow breed, feeding regimes, and environmental management on milk composition.

Key words:

averages, economic impact, heat stress, milk fat, samples, seasonal variation

982-1000 M.A.J.G. Silva, L.M.D. Santos, J.C.D. Ribeiro, M. Barbari, V. Becciolini, L.P. Naves1 and P.F.P. Ferraz
Spatial and temporal variability of enthalpy and its influence on the cloacal temperature of broilers
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Spatial and temporal variability of enthalpy and its influence on the cloacal temperature of broilers

M.A.J.G. Silva¹, L.M.D. Santos², J.C.D. Ribeiro¹, M. Barbari³, V. Becciolini³, L.P. Naves¹1 and P.F.P. Ferraz²*

¹Federal University of Lavras, Animal Science Department, Campus Universitário,
PO Box 3037, Lavras, Minas Gerais, Brazil
²Federal University of Lavras, Agricultural Engineering Departament, Campus Universitário, PO Box 3037, Lavras, Minas Gerais, Brazil
³University of Firenze, Department of Agricultural, Food, Environmental and Forestry Science, Via San Bonaventura, 13, Firenze, Italy
*Correspondence: patrícia.ponciano@ufla.br

Abstract:

Strategies aimed at mitigating heat stress conditions pose a challenge for the poultry industry operating in tropical climate zones. The primary aim of this research was to characterize and analyze the specific enthalpy of air (h, in kJ kg of dry air⁻¹) in a broiler house using geostatistical techniques. In addition, its relationship with the cloacal temperature (t_cloacal, °C) of the broilers was evaluated. The study was carried out in Lavras, Minas Gerais, Brazil. A total of 720 Cobb-500 broilers were raised from 1 to 42 days old. When the broilers were 7, 21, 35 and 42 days old, the dry bulb temperature (t_db, °C) and relative air humidity (RH, %) were recorded at 08:00 a.m. and 01:00 p.m. by seven sensors distributed throughout the installation, and t_cloacalmeasured. Subsequently, h computed, and the data were examined through kriging interpolation. The t_cloacal data were superimposed on the h maps of the facility. The spatial distribution of h inside the aviary (box) and temporal distribution (time and days) were characterized, and its variability was visualized. T_cloacalwas directly related to the spatial as well temporal distribution of h, providing information about the thermal influence on production environment and the physiological responses of broilers.

Key words:

body temperature, geostatistics, heat stress, thermal comfort

1467-1486 R. Goher and M. Akmal
Wheat cultivars exposed to high temperature at onset of anthesis for yield and yield traits analysis
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Wheat cultivars exposed to high temperature at onset of anthesis for yield and yield traits analysis

R. Goher and M. Akmal*

Department of Agronomy, Faculty of Crop Production Sciences, The University of Agriculture, Peshawar-25130, Pakistan
*Correspondence: akmal@aup.edu.pk

Abstract:

Temperature fluxes at some critical growth stages adversely affect the crop yield. Heat stress (HS) of limited duration shows mild to marked effects on crop yield. The study focused on evaluating HS of limited durations on wheat crop effective from anthesis. Four wheat cultivars (Pirsabak-2005, Pakhtunkhwa-2015, Pakistan-2013, and DN-84) and three advanced lines (P-2, P-12, and P-18) were subjected to HS for 48, 72, and 96 h evaluating changes in the yield and yield contributing traits. The experiment was conducted in a randomized complete block design during 2017–18 and 2018–19 at Agronomy Research Farm, the University of Agriculture Peshawar Pakistan. At the onset of anthesis, plants were exposed to HS in the plastic tunnel for limited durations. The temperature inside and outside tents was recorded periodically. The mean across the years showed a significant effect on yield traits by HS imposition at anthesis stage. The mean data across the two years showed a significant effect of HS on yield and yield contributing traits. In comparison with control, spike weight (g) reduced by 29, 40, and 49% under limited HS of 48, 72, and 96 h, respectively. Grains per spike were decreased by 45, 61, and 69% and grain weight by 29, 36, and 45% from control to imposed HS of 48, 72, and 96 h, respectively. Overall grain yield decreased by 44, 61, and 70% upon exposed to 48, 72, and 96 h of HS, respectively. The differences among the cultivars for yield and yield contributing traits were different under various HS conditions. The study concluded that HS effective from anthesis has an adverse effect on grain weight and number and hence the grain yield. Among the cultivars, Pakistan-2013 showed better resistance to HS of limited duration when exposed at the anthesis stage of the crop growth.

Key words:

grain number, grain weight, heat stress, heat-stress duration, wheat yield

552–561 A.V. Miftakhutdinov, E.R. Saifulmulyukov and E.A. Nogovitsina
Alleviation of technological stresses by a feed supplement
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Alleviation of technological stresses by a feed supplement

A.V. Miftakhutdinov, E.R. Saifulmulyukov* and E.A. Nogovitsina

South Ural State Agrarian University, 13 Gagarina street, RU457100 Troitsk, Chelyabinsk Region, Russia
*Correspondence: ernest_saif@mail.ru

Abstract:

Technological stresses affect the productivity of broiler-type chicken and are related directly to poultry farming intensification. Heat stress occurring in conditions of high density keeping, especially at high summer ambient temperatures, is very important. Stress factors influence the metabolic processes in poultry, while reducing the production parameters of operation and, by extension, the efficiency of broiler farming.
The objective of this research was to identify the efficiency of a feed supplement in alleviating technological stresses in poultry industry.
Use of supplement (the preparation contains succinic acid, L-carnitine, betaine, inorganic salts of zinc, manganese, copper and lithium) preserved the production performance of broiler-type chickens in the pre-slaughter period, by reducing the technological load on the poultry body, as it was indicated by an increase in the efficiency of fattening by 16.2 conditional units, meat yield by 1.4%, gross income by 49.2% and a decline in mortality rate by 1.5%. The data on production efficiency indicators of broiler feeding were obtained on a large sample – 6136 heads.

Key words:

broiler-type chicken, development, economic efficiency, growth, heat stress, livability, meat productivity, poultry industry, pre-slaughter period, technological stress

210-223 T. Penev, D. Dimov, I. Marinov and T. Angelova
Study of influence of heat stress on some physiological and productive traits in Holstein-Friesian dairy cows
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Study of influence of heat stress on some physiological and productive traits in Holstein-Friesian dairy cows

T. Penev¹*, D. Dimov¹, I. Marinov² and T. Angelova³

¹Trakia University, Faculty of Agriculture, Department of Applied Ecology and Animal Hygiene, BG6000 Stara Zagora, Bulgaria
²Trakia University, Faculty of Agriculture, Department of Animal Husbandry – Ruminants and Dairy Farming, BG6000 Stara Zagora, Bulgaria
³Institute of Agriculture, BG6000 Stara Zagora, Bulgaria
*Correspondence: tonchopenev@abv.bg

Abstract:

The aim of the research was to study the effect of heat stress (HS) on some physiological and productive traits in Holstein-Friesian dairy cows. The study included 22 cows on different parities. In the building where the cows were housed, the temperature-humidity index (THI) was reported at 10:00 and 15:00 h, at the same time the rectal temperature (RT) and respiratory rate (RR) were reported for each of the examined cows. The daily rumen activity was taken from the SCR system by Allflex. The average THI values in May were 71, in June – 75, in July – 74, and in August – 77, from which it follows that in the summer months the cows were in conditions of mild to moderate heat stress throughout the day. The average daily milk yield of the cows increased from May to June and reached 41.44 kg day^-1, then decreased in July and August to 37.2 and 32.48 kg day^-1, respectively. With an increase in the THI values, an increase in the RR and RT was registered, as in THI above 79 the RR was 56.54 per min, and the RT was 39.33 °C. With increasing the THI values, the rumination of the cows decreased from 563 per day at THI < 72 to 542.5 at THI > 79. In cows with high daily milk yield, a higher RT was registered, and in cows with more than 50 kg per day, the RT was 39.09 °С. A more intense rumination was found in cows with higher daily milk yield. In cows with an average daily milk yield of 33.26 kg, an average of 450 ruminations per day were reported, and in those with an average milk yield of up to 42.89 kg – 650 ruminations per day. From the research conducted it was found that the studied physiological traits – rectal temperature, respiration rate and rumination are influenced by HS and the intensity of this effect depend on the daily milk yield of cows and THI levels.

Key words:

dairy cows, heat stress, rectal temperature, respiratory rate, temperature-humidity index

1068–1081 M.O. Vilela, R.S. Gates, S. Zolnier, M. Barbari, C.G.S. Teles Junior, R.R. Andrade, K.S.O. Rocha, I.F.F. Tinôco, C.F. Souza, L. Conti and G. Rossi
Variable velocity system for evaluating effects of air velocity on Japanese quail
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Variable velocity system for evaluating effects of air velocity on Japanese quail

M.O. Vilela¹*, R.S. Gates², S. Zolnier¹, M. Barbari³*, C.G.S. Teles Junior¹, R.R. Andrade¹, K.S.O. Rocha¹, I.F.F. Tinôco¹, C.F. Souza¹, L. Conti³ and G. Rossi³

¹Federal University of Viçosa, Department of Agricultural Engineering, Av. Peter Henry Rolfs, s/n Campus University of Viçosa, BR36570-900 Viçosa, Minas Gerais, Brazil
²Iowa State University, Departments of Agricultural and Biosystems Engineering, and Animal Science, Egg Industry Center, 1202 NSRIC, Ames, IA 50011, USA
³University of Florence, Department of Agriculture, Food, Environment and Forestry,
Via San Bonaventura, 13, IT50145 Firenze, Italy
*Correspondence: monique.vilela@ufv.br; matteo.barbari@unifi.it

Abstract:

This study documents the design and performance of a system to apply different magnitudes of air velocity to Japanese quail, to evaluate the combined effects of velocity, temperature and humidity on bird behaviour, performance and welfare. The system was developed to simulate observed field conditions occurring in regions with high winds where quail are raised in curtain-sided housing. System performance consisted of characterizing air velocity distribution in cages downstream of the air velocity which was directed at the front of the cages. The system consisted of two fans attached to a 25 cm PVC tube, one at each end, with the outlet airflow directed through a continuous slot over the cage front at the feeder. The design and performance of this experimental system was evaluated, with six such systems were built and utilized in research trials. To assess system performance, air velocity was measured at 275 points per cage uniformly arranged along the three dimensions (length, width and height) in eight cages with zero, 1, 2 or 3 m s^-1 nominal velocity setpoints. Spatial distribution of velocity was analysed by mapping and from descriptive statistics, with attention to the zone closest to the feeder where birds must go to eat. There was no significant difference (P > 0.05) found in mean paired difference of air speed data measured for pairs of front portion cages with similar velocities. A significant positive correlation was found (P < 0.001) between the measured air velocity at paired points in the cages subjected to the same velocity treatment. A comparison of measured mean air velocity to the nominal setpoint values used for experiments indicated that careful attention to outlet adjustment is important, especially at higher nominal velocity setpoint as 3 (± 0.10) m s^-1 which was difficult to achieve with the system. An example of the use of the deployment of the variable velocity system in controlled environment chambers with Japanese quail is provided.

Key words:

cold stress, effective temperature, engineering design, heat stress, wind chill

371–377 M.G.L. Cândido, I.F.F. Tinôco, M. Barbari, L.C.S.R. Freitas, T.C. dos Santos, R.R. Andrade, R.S. Gates, L. Conti and G. Rossi
Effect of environmental temperature during the of brooding period on growing period of pullets viscera and tibia
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Effect of environmental temperature during the of brooding period on growing period of pullets viscera and tibia

M.G.L. Cândido¹*, I.F.F. Tinôco¹, M. Barbari², L.C.S.R. Freitas¹, T.C. dos Santos¹, R.R. Andrade¹, R.S. Gates³, L. Conti² and G. Rossi²

¹Federal University of Viçosa, Department of Agricultural Engineering, Peter Henry Rolfs Ave, s/n, BR 36570-000 Viçosa-MG, Brazil
²University of Firenze, Department of Agricultural, Food, Environmental and Forestry, Via San Bonaventura, 13, IT50145 Firenze, Italy
³University of Illinois, Department of Agricultural and Biological Engineering, 1304 West Pennsylvania Avenue, US61820 Urbana-IL, United States of America
*Correspondence: marciagl.candido@gmail.com

Abstract:

Poultry production in subtropical and tropical regions faces many problems, one of which is the high air temperature causing thermal stress, particularly dangerous in high-producing birds. Thus, the negative effects caused by heat stress (HS) must be managed. The objective of this study was to evaluate the effects of four different levels of HS in viscera and tibia of pullets. A total of 648 chicks (Lohmann LSL Lite) were used in this study in two different phases. The pre-experimental phase (PEP) was from day 1 through 6 weeks of age. The birds were reared with three different environmental temperatures: thermal comfort, hot and cold. The experimental phase (EP) was conducted from the 7th to the 17th week. Pullets from each thermal environment of the PEP were submitted to: 20 °C, 25 °C, 30 °C, 35 °C. At the end of the 17th week of age 120 pullets were euthanatized and the organs, heart, liver, spleen and gizzard were weighed, as also their tibias. Effects of PEP, and its interaction with EP, were not significant (P < 0.05) for viscera and tibia weight. However, a significant increase (P < 0.05) in heart weight with the decrease of the environmental temperature was observed, being the pullets subject to 20 ºC and 25 °C with the heaviest weights. For the liver, pullets subject to the 35 °C had the lowest weight and were different (P < 0.05) from the other three treatments. For gizzard, the difference (P < 0.05) was between the treatments 20 ºC and 35 °C. These results indicate that brooding temperatures tested during the first 6 weeks of life did not affect the viscera and bone weight during the growing phase.

Key words:

heat stress, poultry, pullet, thermoregulation, viscera