تأثير التبريد برش الماء المتبوع بالتهوية على بعض الصفات الفسيولوجية و التناسلية في أبقار الفريزيان بعد الولادة تحت ظروف بيئة المناطق الجافة

الملخص EN

The present study was carried out at the Agricultural Research Station (Animal Production Research Farm) located in Hada Al-Sham of the Jamoum Region.

Experimental Procedures: 1.

Experimental Animals: Thirty lactating purebred Friesian cows 430-480 Kg.

body weight were clinically normal and free from diseases.

The cows were paired into two similar groups according to their age, parity, body weight, and preview yield.

1.

The first group was kept between 10-00 and 16-00 hr.

under cooling system.

Cows were sprinkled for 30 seconds, followed by forced ventilation for 4.5 minutes.

The cooling cycle was repeated every half an hour.

2.

The second group was kept under normal conditions as a control group.

The cows were provided their daily feeding allowances two times a day in two equal amount of ration.

Daily allowances were offered in amount to cover the animal requirement.

Drinking water was available continuously.

The ambient temperature and relative humidity were recorded through the experimental period.

The main results were : a) Physiological reactions ; 1.

Overall means of respiration rate were (58.38–0.36 vs 62.88–0.28 rpm) for cooling and control groups, respectively.

Difference between the two groups was statistically significant (P < 0.01).

2.

Overall means of pulse rate were (61.33–0.28 vs 68.26–0.24 rpm) for cooling and control groups respectively.

Difference between the two groups average was statistically significant (P < 0.01).

3.

Overall means of rectal temperature was (37.63–0.09 vs 38.92–0.07¡C) for the cooling and control groups, respectively.

Difference between the two groups average was statistically significant (P < 0.01).

4.

Overall averages of white skin temperature (WST) and black skin temperature (BST) for animal group kept under cooling by sprinkled water followed by forced ventilation were lower than that for control group.

The black skin temperature (BST) for the two experimental groups were higher than that of white skin temperature (WST).

b- Reproductive Parameters The results, also, indicated that post-partum cervical involution period (PPCI) , first post-partum ovulation period (1st .PPO) and service period length in the cooling group were shorter than that in the control group.

Difference between the two groups averages were statistically significant (P < 0.01).

It was concluded from this study that the adopted cooling system had efficiently ameliorated the depressive effects of summer heat stress prevailing in Saudi Arabia on the performance of Friesian cattle.

It seems that the water sprinkling followed by forced ventilation technique is a simple safe and practical method for decreasing the heat stress effects in dairy cows and consequently improve productivity and reproductivity of cows in hot climate.