Michael Jinsoo Yoo

Advisor: Professor

Kifl e G. Ge-bremedhin

HAIR-COAT CHARACTERISTICS OF

CATTLE

M. Eng Project

Input to heat and mass transfer models

Help us to select animal breed for different envi-ronments

Useful to identify heat tolerant cows

WHY ARE HAIR AND HAIR-COAT PROPER-TIES IMPORTANT?

Physical properties

Optical properties

HAIR COAT PROPERTIES

Hair length (mm)

Hair diameter (µm)

Density of hair coat (hairs/cm2)

Depth of hair coat (mm)

Weight of hair coat (mg/cm2)

PHYSICAL PROPERTIES

VARIATIONS IN PHYSICAL PROPERTIES

Climate conditions

Breed of cows

Body location

Climate conditions

SOURCE OF VARIATION IN PHYSICAL PROP-ERTIES

Weight of hair coat

Depth of hair coat

Hair diameter

January

December

December

Greatest

Maia et al. (2005), Berman et al. (1961)

Breed of cows

SOURCE OF VARIATION IN PHYSICAL PROP-ERTIES

Holstein cow

Braford cow

Sahiwal cow

Jersey cow

Holstein

Cow

Braford

Cow

10.5 mm – 18.33 mmHair length

26 µm – 65.15 µmHair diameter

1.3 mm – 19mmDepth of hair

coat

4.13 mm – 26.50 mmHair length

11.00 µm – 69.00 µmHair diameter

1.00 mm – 13.00 mmDepth of hair

coat

700 hairs/cm2 - 3600 hairs/cm2

Density of hair coat

319 hairs/cm2 - 4851 hairs/cm2

Density of hair coat

SOURCE OF VARIATION IN PHYSICAL PROP-ERTIES

Breed of cows

Rump

Lumbar

Lateral

Belly

Rib

Leg

SOURCE OF VARIATION IN PHYSICAL PROP-ERTIES

Body location

Greatest Location

Hair Length (mm)

Rump

Lumbar

Lateral

Rib

10.18

9.98

9.66

10.70

6.86

Body location (Jersey cow, April)

Belly

Leg

SOURCE OF VARIATION IN PHYSICAL PROP-ERTIES

6.96 8.97

Pan Y.S. (1964)

Hair Diameter (µm)

68.55

63.72

57.56

59.96

46.47

Body location (Jersey cow, April)

SOURCE OF VARIATION IN PHYSICAL PROP-ERTIES

Greatest Location

Rump

Lumbar

Lateral

Rib

Belly

Leg

84.36 98.28

Pan Y.S. (1964)

Density of Hair Coat (hairs/cm2)

2591.5

2179.5

Body location (Bison cow, Febru-ary)

SOURCE OF VARIATION IN PHYSICAL PROP-ERTIES

Greatest Location

Rump

Lumbar

Lateral

Rib

Belly

Leg2325.5

Peters et al. (1964)

Weight of Hair Coat (mg/cm2)

55.34

64.79

Body location (Bison cow, February)

SOURCE OF VARIATION IN PHYSICAL PROP-ERTIES

Greatest Location

Rump

Lumbar

Lateral

Rib

Belly

Leg64.79

Peters et al. (1964)

HAIR-COAT DENSITY PROFILE

Rump 5300hairs/cm2

1.18cm

Lumbar 7300hairs/cm2

1.36cm

Gebremedhin K.G. (unpublished report)

HAIR-COAT DENSITY PROFILE

Lateral 6300hairs/cm2

1.18cm

Belly 6400hairs/cm2

1.3cm

Gebremedhin K.G. (unpublished report)

HAIR-COAT DENSITY PROFILE

Head 3900hairs/cm2

1.06cm

Gebremedhin K.G. (unpublished report)

Absorptivity (α) Amount of incident energy absorbed by the hair coat

Reflectivity (ρ) Fraction of the incident energy reflected back by the hair coat

Transmissivity (τ) Energy transmitted through the hair coat to the skin surface

Absorptivity + Reflectivity + Transmissivity = 1α + ρ + τ = 1

OPTICAL PROPERTIES OF HAIR COAT

SOURCE OF VARIATIONS IN OPTICAL PROP-ERTIES

Color of hair coat

Black hair coatα = 0.98

Dark-red hair coatα = 0.92

Tan hair coatα = 0.75

White hair coatα = 0.37

Gebremedhin et al. (2011)

REFLECTIVITY AS A FUNCTION OF WAVELENGTH FOR DIFFER-ENT COLORS

da Silva et al. (2003)

da Silva et al. (2003)

ABSORPTIVITY AS A FUNCTION OF WAVELENGTH FOR DIF-FERENT COLORS

ABSORPTIVITY OF DIFFERENT HAIR-COAT COLOR

Gebremedhin et al. (2011)

OPTICAL PROPERTIES

Maia et al. (2003)

Pigmented vs. Non-pigmented

CONCLUSION

Physical properties Range

Hair length (mm) 3.46 – 60

Hair diameter (µm) 11 – 123

Depth of hair coat (mm) 1 – 25

Density of hair coat (hairs/cm2) 221 – 7300

Weight of hair coat (mg/cm2) 7 – 108

Factors that affect properties are : body loca-tion, climate condition, and breed of cows.

CONCLUSION

The optical properties of hair coat of cows are sig-nificantly affected by color.

Optical properties Hair-coat color Range

AbsorptivityWhite 0.36 – 0.72

Black 0.88 – 0.98

ReflectivityWhite 0.45 – 0.53

Black 0.046 – 0.089

TransmissivityWhite 0.003 – 0.043

Black 0.01 – 0.019

THANK YOU!