Coat colour contributes to physiological adaptation in mammals and mediates response to thermal stress. Twenty-four adult West African Dwarf sheep of both sexes and with different coat colour types were used in this study. We measured rectal temperature (RT), respiratory rate (RR) and pulse rate (PR) before sunrise and sunset during the late dry season (January-March) and early rainy season (April-June) as well as packed cell volume (PCV), red blood cell (RBC) count, white blood cell (WBC) count, plasma sodium (Na(+)) and potassium (K(+)). Animals with black coat colour had the highest (P < 0.05) mean values of 38.92 ± 0.03 °C, 65.09 ± 1.06 breaths/min, 81.35 ± 0.78 beats/min, 1.70 ± 0.01 for RT, RR, PR and heat stress index (HSI), respectively, followed by brown mouflon and brown with extensive white, while the Badger Face coloured sheep had the least mean values. There were significant (P < 0.05) differences between male and female sheep for RT, RR, PR and HSI. Season had a significant (P < 0.05) effect on RT, RR, PR and HSI. Coat colour and sex also significantly (P < 0.01) affected RBC, WBC, Na(+) and K(+). Seasonal variation (P < 0.05) in all the blood parameters was observed, with the exception of PCV. Interaction effect of coat colour and sex was significant (P < 0.05) on RT and HSI. Correlation coefficients among the measured traits ranged from positive to negative values. These results indicate that selection of white-coloured sheep to attenuate heat stress is desirable in the hot humid tropics.

Rabbit production under tropical conditions is affected by environmental stress mainly from the effect of high ambient temperatures and high humidity, low wind speed and indirect solar radiation. This experiment was conducted to investigate the adaptive potentials of Californian, New Zealand white, Havana black and Palomino brown rabbits to heat stress when raised in humid tropics. A total number of ninety-six rabbits were used. Rectal temperature, respiratory rate, pulse rate and heat stress index were measured in these temperate breeds during rainy and dry season. The results showed that the breed of rabbit had a significant effect (P<0.05) on rectal temperature, respiratory rate, pulse rate and heat stress index. Havana black rabbit had the highest mean rectal temperature value (39.32 ± 0.03°C) followed by Palomino brown (38.97 ± 0.03°C), while the least value was recorded for New Zealand white (38.68 ± 0.02). Respiratory rate values followed the same pattern with that of rectal temperature with higher respiratory rate 69.09 ± 1.05 breaths/min recorded for Havana rabbits. The pulse rate values ranged from 163.23 ± 0.47 - 184.35 ± 0.78 beats/minutes. The highest pulse rate of 184.35 ± 3.78beats/minute was recorded for Havana black. The lowest heat stress index was obtained for New Zealand white followed by California and Palomino Brown while Havana black rabbit had the highest value (1.95± 0.01). The respiratory rate was significantly lower among males as compared to their female counterparts (63.09±0.58 versus 69.54 ± 1.65breaths per minute). The age of the rabbit also significantly affected (P<0.05) the rectal temperature, respiratory rate, pulse rate and heat stress index. 12 weeks old rabbit had the highest mean values while 4 weeks old rabbit had the least values. The heat stress index value obtained during dry season was higher (P< 0.05) than that obtained for rainy season (1.93± 0.02 versus 1.80 ± 0.01). Havana black rabbits and Palomino brown were more prone to heat stress than California and New Zealand white rabbits in tropical environment.

This study was carried out to evaluate the growth performance of Marshall, Cobb and Arbor acre strains of broiler chicken. A total number of three hundred (300) day-old broiler chicks of Arbor acre, Cobb and Marshall strains were raised under the same management condition. Data was obtained on the growth performance and analyzed. Cobb strain had the highest weight of 175.78 ± 2.51g at 2 weeks of age while Arbor acre and Marshall strain had similar (p>0.05) body weight at that age. Marshall had the highest body weight of 1804.37± 50.47g followed by Cobb with a weight of 1760.16 ±15.38g) while Arbor acre had the least body weight of 1683.43 ± 25.06g at 8weeks. Cobb strain had the highest body length (32.33 ± 0.10cm) at 8 weeks. All the strain studied had similar breast girth at 4 weeks. However, Marshall strain had the highest breast girth followed by Arbor acre while Cobb strain had the least breast girth at maturity. Marshall strain and Arbor acre had similar thigh lengths while the least thigh length was recorded for the Cobb strain. The effect of sex was significant (p<0.05) on all the growth parameters at 8weeks as male broilers had higher body measurements than their female counterparts. In conclusion, Marshall strain had better growth performance than Arbor acre and Cobb strain of broiler chicken.

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One hundred and seventy six lambs produced by 84 ewes in their first to seventh parity were used to determine the effect of the number of births of ewe on the pre-weaning morpho metric traits of West African dwarf lambs.Body weight (BW), body length (BL), heart girth (HG) and height at wither (HW), were taken at birth, 4, 8 and 12 weeks after birth. Pre-weaning morpho metric traits of the lambs were significantly (P<0.05) affected by the parity of the ewe. The heaviest birth weight was recorded for lambs produced by fifth-parity ewes while the lambs from first parity had the least value. The highest value of BW, BL, and HW (4.74 ± 0.07kg, 37.00 ± 1.18cm, 41.32 ± 0.23cm) and (6.47 ± 0.09 kg, 40.40 ± 0.81cm, 46.11 ± 0.54 cm) were recorded from ewes in their fifth parity at weeks 4 and 8; respectively. Lambs produced by sixth parity ewes had the highest value of HG (39.00 ± 0.32cm, 42.01 ± 0.16 cm, and 42.80 ±0.86 cm) at birth, and 4 and 8 weeks after birth; respectively.However, the effect of parity on the growth performance tended to disappear at week 12. Sexual dimorphism was observed on all the morpho metric traits at week 12 in favour of male lambs. Growth performance of the lambs increases with parity though the effect was less significant at weaning.

This experiment was carried out to determine the effect of coat pigmentation on feed and water intake of West Africa Dwarf Sheep using 24 weaned lambs with different coat pigmentations. Feed intake of Panicum maximum and concentrate feed, water consumption, weight gain as well as feed efficiency were measured. The analysis of variance showed that the effect of coat pigmentation was significant (p< 0.05) on forage intake, weight gain, feed efficiency and water consumption. However, concentrate feed intake was not significantly (p>0.05) affected by coat pigmentation. The least value of weight gain was recorded for black sheep with the weekly gain of 0.49 ± 0.19kg. There was no significant difference in the weekly weight gain of brown sheep and white sheep with 0.69 ±0.12kg and 0.60 ± 0.15kg respectively. Brown coat pigmentation type had the highest feed efficiency of 0.25± 0.05 followed by white sheep (0.21 ±0.03) while the black sheep had the least feed efficiency (0.18 ± 0.02). The mean daily water consumption of the WAD sheep ranged from 0.96 ± 0.02 litre to 1.50 ±0.02 litre with the brown sheep having the highest water consumption while black sheep had the least. Female sheep had lower feed efficiency and water consumption than male sheep. In conclusion, animals with light pigmentation had higher values for feed intake, daily water consumption and feed efficiency than the dark (black) pigmentation.

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