Oestrus synchronization and subsequent conception rates of prostaglandins in the beef herd
1988
Preecha Innurak | Kanchana Markvichitr | Sithichai Kaewsuwan (Kasetsart Univ., Bangkok (Thailand). Faculty of Agriculture. Dept. of Animal Science)
Two trials of oestrus synchronization by using natural prostagtandin F2 alpha (PGF2a) were carried out on beef cattle breeding females, whose age ranged between 3 to 13 years old. (Native, crossbred Brahman and crossbred Chorolais). The first trial was performed on 12 cows in luteal plase (diameter of cyclic corpusluteum between 0.8-1.2 cm) by using one dose injection of 25 mg PGF2a. Whereas the second trial was performed on 16 cows in non luteal phase (inactive corpusluteum or non corpusluteum) by using double doses injection of 25 mg PGF2a 11 days apart. Insemination with proven sire frozen semen was carried out by the time of 80 hrs one dose after treated of PGF2a in first trial and also one dose after the second injection of PGF2a in second trial, either the cows were observed oestrus symptom or not. Pregnancy rate was diagnosed per rectum about 60 days post insemination, pregnancy rate of the cows in first trial and second trial were 58.3 % and 25.0 % respectively.
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