Effect of Friesian Dairy Cows’ Coat Color on Their Productive Performance under Heat Stress Conditions
Effect of Friesian Dairy Cows’ Coat Color on Their Productive Performance under Heat Stress Conditions
Ashraf Ali Mehany1, Wael Mohamed Wafa1, Al-Moataz Bellah Mahfouz Shaarawy1, A. F. A. El-Hawary1, Mahmoud Sayed Sayah2,1, Adel Bakr3, Reda Abdel-Samee Ahmed Rezk4, Shimaa M. Ali1*
ABSTRACT
Dark-coated cattle absorb more solar radiation than lighter-coated ones, increasing heat stress and reducing productivity. The present study aimed to select the best percentage of white vs. black skin coat color of Friesian dairy cows and its effect on their productive performance under Delta Egyptian conditions during the hot months. The study included 20 mid-lactating dairy cows, aged 3–8 years and with 2–5 parities, housed loosely in the same yard with semi-open sheds throughout the experimental periods from 1st June to 30th August 2022. Animals were split up into two similar groups (10 each) by related percentage of white (WH) vs. black (BK) area on the skin coat. The first group (G1) is called dark-colored cows because it had 25% WH and 75% BK, and the second group (G2) is called light-colored cows because it had 50% WH and 50% BK. The current results showed that over different experimental months, all analyzed thermoregulatory responses such as skin and rectal temperatures, pulse and respiration rates were considerably (P < 0.001) higher in G1 than in G2. Thyroid hormones (T3 and T4) and cortisol levels were considerably (P < 0.001) reduced, although prolactin was considerably elevated, while thyroid stimulating hormone was not affected in G2 compared to G1 under heat stress conditions. Serum urea and sodium concentrations were significantly (P < 0.001) increased, but potassium was significantly (P < 0.05) decreased, while serum phosphorus was not affected in dark-colored cows compared to light-colored cows. Daily milk yield, and percentages of total solid, solid not-fat, milk protein, and milk fat were significantly (P < 0.01) increased by 12.16%, 3.64, 4.67, 10.20%, and 1.41% in light-colored cows compared to dark-colored cows throughout the experimental months. It was concluded that there is a negative relationship between black fur-colored cows and physiological status, milk yield, and composition under thermal-stress conditions. Cows with a larger black surface area may be more susceptible to the harmful impacts of thermal stress due to greater absorption of solar radiation as heat.
Keywords | Coat color, Friesian cows, Physiological status, Productive performance, Heat stress
To share on other social networks, click on any share button. What are these?
