تأثير مستوى إنتاج الحليب و بعض العوامل الأخرى في معامل التحمل الحراري لدى أبقار الفريزيان في الأجواء الحارة

Abstract EN

36Multifarious Friesian were used belonged to AL-Ishaqi Cattle Station north Baghdad for the period from 1/6/2010 to 1/11/2010.

Using the records of cows in the station for milk production and divided of production to three levels (less than 5 , 6-13 & more than 13 kg/day) , parity , pregnancy state also, its divided according to body condition to three groups underweight , medium and overweight) and degree of spotting (white ,black and mixed between them) from the eye observation.

The study of this factors on Heat Tolerance Coefficient per cow with according to group in factors.

Highly significant effect of level of milk production in first month, the cows gave more than 13 kg/day recorded increased in Heat Tolerance Coefficient which was 94.03 % compare with level of 5-13 kg/day (92.09 %) and cows in level of less than 5 kg/day (90.42 %) and this continuous effect to end of experiment.

Significant increase of Heat Tolerance Coefficient in cows in fourth parity in most of the experiment period.

A Significant (P≤0.05) effect of degree of spotting on Heat Tolerance Coefficient in this experiment, advantage for cows color white compare with mixed and black color of cows.

while Nonsignificant effect of body condition or pregnancy in Heat Tolerance Coefficient.

In conclusion white colors cows with fourth parity and produce milk more than 13 kg/day milk have ability carry out high temperature which lead have a high Heat Tolerance Coefficient.