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 ± 1.29
cm) and tail length (22.10 ± 0.89 cm), while brown (Bb) coat colour had the
least value of 53.00 ± 6.00 cm for rump height and 17.50 ± 0.50 cm for tail
length. The CCG had significant (P < 0.01) effect on body temperature and
pulse rate, with the grey/mouflon (Ag) colour possessing the highest
body temperature (38.90°C ± 0.22°C), and Bb having the least value of 37.20°C ± 0.35°C. White/tan (Awt) had the highest pulse rate
of 28.90 ± 0.66 beats/min and Bb had the least value of 20.00 ± 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 ± 0.00 L) and badgerface (Ab)
having the least value (11.50 ± 0.62 L). The Bb had the highest value (5.60 ± 0.00
fL) for MPV and Ab had the least value (4.70 ± 0.15 fL). Sheep with
Bb and Ab were found to withstand heat stress better than others.