Effects of coat colour genes on body measurements, heat tolerance traits and haematological parameters in West African Dwarf sheep

With 178 West African Dwarf sheep aged 1 to 3 years, a study was conducted to investigate the effects of coat colour genes on body measurements, heat tolerance traits and haematological parameters. Body measurements considered included body length, hair length, ear length, hip width, tail length, height at withers, rump height, fore cannon bone length, chest depth, heart girth and body weight. Heat tolerance traits considered were skin temperature, rectal temperature, pulse rate and respiratory rate. Blood samples were collected for the evaluation of white blood cell (WBC), red blood cell (RBC), haemoglobin (HGB), haematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin cell (MCHC), red cell distribution width (RDW), platelets (PLT), mean platelets volume (MPV), platelets distribution width (PDW) and plateletcrits (PCT). Results showed that coat colour gene (CCG) had significant (P < 0.01) effect on rump height and tail length. Animals with black (BB) coat colour had the highest mean value for rump height (57.80 plus or minus 1.29 cm) and tail length (22.10 plus or minus 0.89 cm), while brown (Bb) coat colour had the least value of 53.00 plus or minus 6.00 cm for rump height and 17.50 plus or minus 0.50 cm for tail length. The CCG had significant (P < 0.01) effect on body temperature and pulse rate, with the grey/mouflon (A super(g)) colour possessing the highest body temperature (38.90 degree C plus or minus 0.22 degree C), and Bb having the least value of 37.20 degree C plus or minus 0.35 degree C. White/tan (A super(wt)) had the highest pulse rate of 28.90 plus or minus 0.66 beats/min and Bb had the least value of 20.00 plus or minus 2.00 beats/min. The CCG had significant (P < 0.01) effect on RBC and MPV with brown (Bb) colour having the highest RBC counts (18.20 plus or minus 0.00 L) and badgerface (A super(b)) having the least value (11.50 plus or minus 0.62 L). The Bb had the highest value (5.60 plus or minus 0.00 fL) for MPV and A super(b) had the least value (4.70 plus or minus 0.15 fL). Sheep with Bb and A super(b) were found to withstand heat stress better than others.