الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The current study was designed to monitor the reproductive and productive performance of Holstein dairy breed by application several TAI protocols to 1-To determine the most effective program increasing the conception rate 2- To determine the best ovarian state in which the ovary respond to synchronize agent. 3-To show the effect of thyroxin hormone on the success of synchronization program. 4- To determine the best hormonal state of the animal in which it respond to synchronization program. A total number of using 72 lactating Holstein cows (2.4 to 8 years old) , ( 1 to 5 lactation seasons) , (DIM was 60-145 d) in addition to 10 Holstein heifer of range B.W 385kg, and 14.9 to 17 month age at the private dairy farm in Borg al- Arab area were not detected in estrus. Rectal examination was conducted to determine any palpable lesion in the reproductive tract or ovaries, Moreover the ovarian structure at the day of the beginning of the protocol application was determined (the most palpable ovarian findings were small follicle (SM) , small CL(SCL), or smooth inactive ovaries (SIO)). Animals were divided in 5 groups according to the ovarian structures (small follicle, small CL and SIO).