Heat Stress in Dairy Cattle

Shearer, Jan K.

doi:10.1002/9780470752401.ch8

Cited by 11 publications

(3 citation statements)

References 18 publications

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“…The impact of roof insulation on the variability of footing temperature was surmised to be the result of solar radiation's ability to transfer heat through the roofing in the absence of insulation. A roof with no insulation will have higher temperatures on the inside of the roof than one with insulation as the solar heat load will be evident on the inside of the structure, and a radiant heat load could impact the footing temperatures within the indoor arena (Bond et al, 1961;Buffington et al, 1983;Shearer et al, 1999). As heat transfers through metal roofing very effectively, heat generated from solar radiation on the roof will be transferred to the material on the underside of the roof.…”

Section: Components Of the Indoor Arenamentioning

confidence: 99%

Environmental spatial mapping within equine indoor arenas

McGill,

Coleman,

Jackson

et al. 2023

Front. Anim. Sci.

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Equine indoor arenas are unique infrastructure investments found at equine farms and facilities. Environmental concerns within these facilities (temperature, respirable dust, moisture, and air movement) have been identified through surveys and small research studies. Thirty-seven indoor arenas at equine facilities within 160 km (100 miles) of Lexington, KY, were visited from August 2018 to August 2021. Semi-structured interviews were conducted to gather more information regarding the environment within the indoor arena and information about the equine facility. Site assessments were also conducted and temperatures (footing or ground level, air at 1.37 m above the footing, and roof), air speeds at 1.37 m above the footing, and light levels at 1.37 m above the footing across the indoor arena spaces were measured, in addition to the total number of horses at the facilities and daily average and maximum use of the indoor arenas. Spatial mapping was conducted using ArcMap 10.7 (Esri; Redlands, California), with kriging being used for the interpolation. The created maps were used to determine the variability of the temperatures, air speed, and lighting within the indoor arenas. These variabilities were examined for the statistical significance for variables of the indoor arenas that were determined by structural and design aspects and for facility usage information gathered from the semi-structured interviews. The variables that were statistically significant were roof ventilation for roof temperature variability, roof insulation for footing temperature variability, building enclosure for lighting variability, total number of horses at the facility for lighting variability, and total daily number of horses in the indoor arena for the ambient air temperature variability. One of the most significant results was the lack of air movement observed in the majority of the indoor arenas. Over 80% of the indoor arenas were experiencing still air speed conditions (< 0.51 m/s) during the site assessment. There is a need for more research on the environmental conditions within indoor arenas, the potential health impacts to the humans and horses in the spaces, and how design changes to the facilities could improve these environments.

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Section: Components Of the Indoor Arenamentioning

confidence: 99%

Environmental spatial mapping within equine indoor arenas

McGill,

Coleman,

Jackson

et al. 2023

Front. Anim. Sci.

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“…Thermal stress does not prevent the occurrence of normal estrus cycles. It does, however, amplify the problem of heat detection by reducing the length of the estrus period, from 18 hours down to about 10 hours, and lowering the intensity of estrus behavior (Shearer, 1990). Thermal stress compromises oocyte growth in cows by altering progesterone, luteinizing hormone, and follicle-stimulating hormone secretions during the estrus cycle (Ronchi et al, 2001), as well as impairing embryo development and increasing embryo mortality (Wolfenson et al, 2000).…”

Section: Effects On Reproduction Traitsmentioning

confidence: 99%

Review on performance responses of dairy cattle against thermal stress

Mohammed

2023

Ethiop. Vet. J.

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This manuscript is aimed at reviewing the performance responses of dairy cattle against thermal stress resulting from climate change. Climate change is the major factor that largely affects the dairy industry. Thermal stress (TS) is the perceived discomfort and physiological strains associated with exposure to excessive ambient temperature. Temperature and Humidity Index (THI) have been adopted to describe thermal conditions that drive thermal stress in dairy cattle. The effects of TS are devastating in the dairy industry if not managed well. The thermo-neutral zone for dairy cattle and calves in the tropics is THI <72. Milk yield reductions of up to 50% have been reported for Holstein cows due to thermal stress under summer climate conditions. Moreover, thermal stress is associated with alterations in milk composition. TS reduces the length and intensity of estrus manifestation. Moreover, 80% of estrus may be unnoticeable during the summer season in temperate regions, which further reduces fertility. Conception rates of dairy cows may drop up to 20–27% in the summer season. Climate-induced thermal stress resulted in a decrease of 3.5 kg and 25 kg in the birth weight and weaning weight of Fogera calves, respectively. Dry matter feed intake was reduced by 9.6%. Commonly used thermal stress reduction strategies included modification of the physical environment, breeding for heat-tolerant dairy cattle, and nutritional management. The productive and reproductive traits are susceptible to the negative impacts of thermal stress with an increase in THI above 68.0 for Holstein Frisian cattle and their crosses and 72 for tropical cattle under an open shed system. Mitigations of thermal stress by breeding heat-tolerant animals, using a loose house system, and season-based feeding should be considered an integral component of the dairy cattle management system.

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“…Ya que la utilización conjunta de ventilación artificial y nebulización permite disminuir la temperatura del establo entre 8 a 12ºC (Shearer et al, 1991).…”

Section: Indicadores Ambientales Indicadores Fisiológicosunclassified

Predicción de estrés térmico en vacas lecheras mediante indicadores ambientales y fisiológicos

et al. 2016

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Holstein-Frisia. Índice de temperatura humedad. Frecuencia respiratoria. Temperatura rectal. Producción de leche. resUMenLas vacas lecheras son animales muy sensibles a los cambios ambientales y requieren alojamientos cada vez más sofisticados para prevenir la aparición de estrés térmico en épocas calurosas que eviten importantes pérdidas económicas por la disminución de producción. El objetivo del presente estudio consistió en la valoración en explotación de indicadores ambientales y de indicadores fisiológicos de estrés de las vacas y su influencia sobre la producción de leche. Se monitorizaron la temperatura y la humedad relativa del aire a intervalos de una hora, a través de sondas digitales colocadas en 4 explotaciones durante 365 días. Paralelamente se recogieron indicadores fisiológicos (temperatura rectal y frecuencia respiratoria) en los animales, en invierno y en verano. Los resultados mostraron temperaturas superiores a 25° C durante 48 días del año, siendo los períodos más críticos primavera y verano. La humedad relativa tuvo una variación de 10 % entre invierno y verano. El índice temperatura humedad (ITH) superó el valor de 72 en 51 días anualmente y el período más crítico de la jornada fue entre las 12:00 y las 16:00 horas (P4), con un ITH medio de 68,0. El paso del ITH de 72 por encima de 78 significó un incremento de 1,3 °C y 37,3 respiraciones por minuto en las vacas lecheras. Se encontró una correlación alta entre la frecuencia respiratoria, temperatura rectal y ambas con el ITH, por lo que estos indicadores fisiológicos resultan ser excelentes predictores de estrés térmico. Los animales expuestos a ITH superior de 78 sufrieron una pérdida de producción de leche de 1,8 kg/vaca/día. Dairy cows have become very sensitive animals to environmental changes, requiring increasingly sophisticated accommodations to prevent the stress that would lead to major production and economic losses. The aim of this study was to assess environmental and physiological indicators of stress in cows and their influence on milk production. The temperature and relative humidity was monitored at intervals of one hour through digital probes placed in four farms for 365 days. Alongside two animal physiological indicators (rectal temperature and respiratory rate) were collected, in winter and summer. The results showed the presence of 48 days in a year with temperatures above 25 °C, with the most critical periods occurring in spring and summer. The relative humidity ranged from just 10 % between winter and summer. The Temperature Humidity Index (THI) exceeded the value of 72 on 51 days per year. The most critical period of the day recorded was between 12:00 to 16:00 p.m. (P4) where the average of THI was 68.0. From THI value below 72 to above 78, a rise of 1.3 °C and 37.3 breaths/minute was observed in the monitored dairy cows. We found a high correlation between respiratory rate and rectal temperature and of both with the THI, highlighting these physiological indicators as excellent predictors of heat stress. The animals ...

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Heat Stress in Dairy Cattle

Cited by 11 publications

References 18 publications

Environmental spatial mapping within equine indoor arenas

Environmental spatial mapping within equine indoor arenas

Review on performance responses of dairy cattle against thermal stress

Predicción de estrés térmico en vacas lecheras mediante indicadores ambientales y fisiológicos

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