Quantitative Analysis of the Heat Exchange through the Fur Layer of Holstein Calves

Gebremedhin, K. G.; Porter, Warren P.; Cramer, C. O.

doi:10.13031/2013.33902

Cited by 36 publications

(13 citation statements)

References 8 publications

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“…Other papers reported similar results for hair length 29 and for coat thickness 25 . These results agree with those described by theoretical physics of heat transfer in hair coats 1,5,6,7,8,30 where coat with thick, short, packed, well settled hair presents high latent and sensible flux from the skin to the coat surface.…”

supporting

confidence: 91%

Variação genética das características do pelame e da produção de leite em vacas Holandesas manejadas à sombra em ambiente tropical

Maia

Silva

Bertipaglia

et al. 2005

Braz. J. Vet. Res. Anim. Sci.

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Present study is aimed at an evaluation of the genetic and environmental effects of the coat colour and physical characteristics on the first lactation yield in Holstein cows managed under shade. Data from 449 cows were analyzed by the least-squares method and Restricted Maximum Likelihood (REML) was used to estimate (co)variance components under the Animal Model. The results showed that predominantly white Holstein cows tended to present higher milk yield than those predominantly black, when managed in large stalls with fans and sprinklers in a tropical environment. The physical characteristics have negative association with milk yield, except for the hair diameter. This association favours the heat transfer through the coat and is widely favourable in hot environments. High heritability estimates together with the high genetic correlations of milk yield and the hair properties is an evidence of the possibility of a selection for increased milk yield together with the selection towards a less dense coat with thick, short, settled hairs.

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supporting

confidence: 91%

Variação genética das características do pelame e da produção de leite em vacas Holandesas manejadas à sombra em ambiente tropical

Maia

Silva

Bertipaglia

et al. 2005

Braz. J. Vet. Res. Anim. Sci.

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“…Hence, environmental conditions forced animals with coat characteristics less favourable to heat dissipation to reduce T 4 concentration to ensure homeostasis by diminishing endogenous heat production. Animals that showed coat characteristics that promote heat dissipation, such as short hair and low hair density (Gebremedhin et al 1983), were able to maintain the highest T 4 concentrations. The T 4 hormone plays an important role in livestock productivity (Todini et al 2007).…”

Section: Resultsmentioning

confidence: 99%

Thermoregulatory responses related to coat traits of Brazilian native ewes: an adaptive approach

Leite

Façanha

Costa

et al. 2017

Journal of Applied Animal Research

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Semi-arid conditions can adversely affect livestock productivity and change certain physiological parameters. The relationship between hair coat and thyroxine levels in Morada Nova ewes was evaluated through environmental factors, such as air temperature, relative air humidity, radiant and Black Globe Humidity Index to gain a better understanding of thermoregulation mechanisms in these animals. Measurements were taken from July to January in 383 Morada Nova ewes. The variables studied included rectal temperature (RT), respiratory rate (RR), coat thickness (CT), hair length (HL), hair diameter (HD), hair density (D) and thyroid hormones. The data underwent multivariate statistical analyses and a significant inverse relationship was found between coat traits and Thyroxine (T 4 ). The animals that exhibited greater HL, coat density and CT showed lower T 4 concentrations. Coat traits showed a strong interaction with physiological mechanisms and can be considered relevant in maintaining homeostasis. Hair traits play an important role in this process, since T 4 reduction was stronger in animals that showed difficulties in eliminating heat, which were the ones that had greater HL, hair density and HD. By contrast, animals with a hair coat more favourable to heat losses had higher levels of thyroid hormones. ARTICLE HISTORY

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“…More recently, models have been refined as the heat and mass transfer relationships become better understood and as more measurements are collected on thermoregulatory responses and morphological characteristics of cattle (36,(48)(49)(50)(51)(52)(53). These models examine the complexities of sensible and latent heat flow from the skin surface and hair coat where the cow interacts with its environment.…”

Section: Modeling Heat Exchange Between An Animal and The Environmentmentioning

confidence: 99%

“…These models examine the complexities of sensible and latent heat flow from the skin surface and hair coat where the cow interacts with its environment. It should be noted that the climatic energy demands (food and water requirements) for a cow are a coupled heat and mass transfer problem and can be determined from an energy balance on the skin surface (48).…”

Section: Modeling Heat Exchange Between An Animal and The Environmentmentioning

confidence: 99%

Thermal Biology of Domestic Animals

Collier

Gebremedhin

2015

Annu. Rev. Anim. Biosci.

174

103

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The thermal environment is the most important ecological factor determining the growth, development, and productivity of domestic animals. Routes of energy exchange (sensible heat and latent heat) between animals and their environment are greatly influenced by body weight, fat deposition, hair-coat properties, functional activity, and number of sweat glands, as well as the presence or absence of anatomical respiratory countercurrent heat exchange capability. Differences in these anatomical features across species have led to specialization of heat exchange. Thermal plasticity and degree of acclimation are critical factors determining the ability of animals to respond to environmental change. Increases in productive capability of domestic animals can compromise thermal acclimation and plasticity, requiring greater investments in housing systems that reduce variability of the thermal environment. The combination of steadily increasing metabolic heat production as domestic animal productivity increases and a rising world temperature poses ongoing and future challenges to maintaining health and well-being of domestic animals.

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Quantitative Analysis of the Heat Exchange through the Fur Layer of Holstein Calves

Cited by 36 publications

References 8 publications

Variação genética das características do pelame e da produção de leite em vacas Holandesas manejadas à sombra em ambiente tropical

Variação genética das características do pelame e da produção de leite em vacas Holandesas manejadas à sombra em ambiente tropical

Thermoregulatory responses related to coat traits of Brazilian native ewes: an adaptive approach

Thermal Biology of Domestic Animals

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