Thermoregulatory responses of Baladi and crossbred goat does under subtropical conditions

Abstract EN

This experiment was conducted to study the effect of heat stress on thermoregulatory responses in Baladi and crossbrd (50% Baladi x 50% Zaraibi) female goats reared under desert of Inshas area during estrous cycle, pregnancy stages and postpartum periods under hot season (period from May, 2014 to October, 2014) compared with mild season (period from October, 2013 to March, 2014) and measure the difference between performance of crossbred animals and performance of the breed that were crossed to evaluate adaptability of two breed throughout these stages, point out hot climate condition of Egyptian environment.

It has been used in this research 40 mature female goats (20 Baladi and 20 crossbred (50% Zaraibi x 50% Baladi) with an average age of 2-3 years and an average body weight was ranging from 25±1.5 kg to 35±1.6 kg for Baladi and crossbred, respectively, the experiment lasted for two seasons (mild and hot).

The animals were kept in semi-open pens during the experimental period and allowed to graze for five hours daily at least.

Thermoregulatory responses of the animal were estimated in terms of rectal temperature (RT), skin temperature (ST) and respiratory rate (RR).Results showed significant decrease (P<0.0001) in RT, ST and RR during mild season as compared with hot season during the estrous cycle.

Also, crossbred showed lower (P<0.01 or P<0.05) RT in comparison with Baladi goat does during different stages of estrous cycle.

While ST and RR showed insignificant variations between crossbred and Baladi goat does during different stage of estrous cycle.

During pregnancy stages Baladi and crossbred goat does recorded significant low (P<0.0001) RT, ST and RR under mild season compared with hot season throughout different stages of pregnancy.

Crossbred showed lower (P<0.05 or P<0.0001) RT than Baladi goat does during different stages of pregnancy, however insignificant variations in ST and RR between crossbred and Baladi goat does during different stages of pregnancy.

During postpartum periods Baladi and crossbred goat does recorded significant low (P<0.05 or P<0.0001) RT, ST and RR under mild season in comparison with hot season throughout different stages of postpartum.

While RT showed significant variation (P<0.05) between crossbred and Baladi goat does in different stages of postpartum (day of parturition and 15 days postpartum), except 30 days postpartum which insignificantly affected by breed.

ST showed significant variation (P<0.01) between crossbred and Baladi goat does in 30 days postpartum only.

However RR showed significant (P<0.05 or P<0.01) decrease in crossbred as compared with Baladi goat does in different stages of postpartum.

From the present results, it could be concluded that, each of season, goat breed and physiological status were affected on rectal temperature, skin temperature and respiration rate throughout the estrous cycle, pregnancy stages and postpartum period of Baladi goat does and its crosses with Zaraibi (50% Baladi x 50% Zaraibi).