Hair-coat Characteristics of Cattle

1. Hair-coat Characteristics of Cattle Michael JinsooYoo Advisor: Professor Kifle G. Gebremedhin M. Eng Project

2. Why are hair and hair-coat properties important? • Input to heat and mass transfer models • Help us to select animal breed for different environments • Useful to identify heat tolerant cows

3. Hair coat properties • Physical properties • Optical properties

4. Physical Properties • Hair length (mm) • Hair diameter (µm) • Density of hair coat (hairs/cm2) • Depth of hair coat (mm) • Weight of hair coat (mg/cm2)

5. Variations in Physical Properties • Climate conditions • Breed of cows • Body location

6. Source of Variation in Physical Properties • Climate conditions Greatest January Weight of hair coat December Depth of hair coat December Hair diameter Maia et al. (2005), Berman et al. (1961)

7. Source of Variation in Physical Properties • Breed of cows Holstein cow Sahiwal cow Jersey cow Braford cow

8. Source of Variation in Physical Properties • Breed of cows Density of hair coat Density of hair coat Depth of hair coat Hair diameter Depth of hair coat Hair length Hair length Hair diameter 4.13 mm – 26.50 mm 11.00 µm – 69.00 µm 26 µm – 65.15 µm 1.00 mm – 13.00 mm 700 hairs/cm2 - 3600 hairs/cm2 10.5 mm – 18.33 mm 319 hairs/cm2 - 4851 hairs/cm2 1.3 mm – 19mm Holstein Cow Braford Cow

9. Source of Variation in Physical Properties • Body location Rump Lumbar Rib Lateral Belly Leg

10. Source of Variation in Physical Properties • Body location (Jersey cow, April) Greatest Location Hair Length (mm) 9.98 10.18 6.86 Rump 9.66 Lumbar Rib 10.70 Lateral Belly 6.96 8.97 Leg Pan Y.S. (1964)

11. Source of Variation in Physical Properties • Body location (Jersey cow, April) Greatest Location Hair Diameter (µm) 63.72 68.55 46.47 Rump 57.56 Lumbar Rib 59.96 Lateral Belly 84.36 98.28 Leg Pan Y.S. (1964)

12. Source of Variation in Physical Properties • Body location (Bison cow, February) Greatest Location Density of Hair Coat (hairs/cm2) 2179.5 Rump 2591.5 Lumbar Rib Lateral Belly 2325.5 Leg Peters et al. (1964)

13. Source of Variation in Physical Properties • Body location (Bison cow, February) Greatest Location Weight of Hair Coat (mg/cm2) 64.79 Rump 55.34 Lumbar Rib Lateral Belly 64.79 Leg Peters et al. (1964)

14. Hair-coat Density Profile Rump • 5300hairs/cm2 • 1.18cm Lumbar • 7300hairs/cm2 • 1.36cm Gebremedhin K.G. (unpublished report)

15. Hair-coat Density Profile • 6300hairs/cm2 • 1.18cm Lateral Belly • 6400hairs/cm2 • 1.3cm Gebremedhin K.G. (unpublished report)

16. Hair-coat Density Profile Head • 3900hairs/cm2 • 1.06cm Gebremedhin K.G. (unpublished report)

17. Optical Properties of Hair Coat • 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 = 1 α + ρ + τ = 1

18. Source of Variations in Optical Properties • Color of hair coat Tan hair coat α = 0.75 White hair coat α = 0.37 Black hair coat α = 0.98 Dark-red hair coat α = 0.92 Gebremedhin et al. (2011)

19. Reflectivity as a function of wavelength for different colors da Silva et al. (2003)

20. absorptivity as a function of wavelength for different colors da Silva et al. (2003)

21. Absorptivity of Different Hair-coat Color Gebremedhin et al. (2011)

22. Optical Properties • Pigmented vs. Non-pigmented Maia et al. (2003)

23. Conclusion • Factors that affect properties are : body location, climate condition, and breed of cows.

24. Conclusion • The optical properties of hair coat of cows are significantly affected by color.

25. Thank You!