Authors: M. RIFAT SALMANOĞLU, EROL ALAÇAM, MUSTAFA ÇELEBİ, AHMET BAŞ
Abstract: The aim of this study was; timing of prostaglandin F_2 alpha (PG) injections for the controlled inseminations in cows by rapid progesterone test (RPT) within post calving 50-60 days, pregnancy determination on post breeding 21st days by RPT and fertility comparisons ofthe PG treatment and spontan estrous groups during the trial. Total 60 Holstein cows, between 3-10 ages, randomly sampled from Polatlı and Bala official farms (TİGEM) were included in this study. The cows starting from post calving 50.60th days were divided into 3 groups, each having 20 cows. The cows having spontan estrouses were inseminated after the RPT controls in the first group. Second group of cows were inseminated after cloprostenol injections (500 mcg, i.m.), initial diagnosis of the 5-15th days of the sexuel cycle by RPT in milk samples. The cows in the last group were inseminated after two PG injections eleven days apart, again with the initial controls by RPT. Moreover, quantitave EIA tests were performed on 80 milk samples as a gold standart. The cows either having spontan estrouses or PG injected, were inseminated artificially. Pregnancy and fertility determinations were peformed on 21st day by RPT and 60-90 days by rectal examination. Diagnosing rate of the estrous symptoms by RPT were 100% in the first group of cows. The result of quantitative EIA results were parallel as RPT test. While RPT results were correct at 100% level either in luteal phase or estrous, the pozitive pregnacy results were only 50% parallel with the former HPT results. In the control tests of this group by quantitave EIA, 5 cows were low progesterone level and the other 5 cows were similar to the standart of RPT. While 11 cows having no CL on their ovaries before the first PG injections,this number was 6 cows, before the second injections. Pregnancy determination results, performing on 21st days by RPT showed 85, 50 and 70% pregnancy in the 1st, 2nd and 3rd groups respectively, Pregnancy rates according to 21st and 60-90 days were parallel in the rate of 88, 80 and 85% in the study groups respectively. Early embryonic loses may be the cause of this decreasing rate of pregnancy examination results between two dates. As a conclusion, the cows starting the post calving 50th days could be use for PG controlled breeding after the deciding of luteal phase of the cycle by RPT. With the two PG injections eleven days apart, the better synchronization and fertility rates was obtained respect to the single injection group.
Keywords: Dairy cow, Rapid progesterone test, Prostaglandin F_2 alpha, Artificial insemination, Fertility
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