Abstract:
The study was conducted between October 2015 and June 2016 in the zootechnical biobase of Research and Development Station Breeding Cattle, Dancu, Iasi on Romanian Black Spotted breed dairy cows, in free system of modernized shelter, with a capacity of 200 heads/shelter. The study aimed at establishing the effectiveness of two methods for the induction and synchronization of estrus in dairy cows, based on gestagens and prostaglandin F2α respectively, in relation to their metabolic status. Depending on the applied treatments, two experimental groups were established: E1 group, composed of 13 cows, of which 7 cows with corpus luteum and 6 cows without corpus luteum), which were treated with progesterone administrate through a intravaginal device (PRID) for 7 days and prostaglandin (PG)F2α 24 hours before the removal of device . E2 group, composed of 29 cows with a corpus luteum were treated with single dose of prostaglandin (PG)F2α.. The average interval from the calving to treatment was 89.60+6.607 days (E1 group), respectively 113.40 ± 5.851 days (E2 group). Blood samples for biochemical analysis (total seric protein, serum albumin, total cholesterol, GGT, ALT, AST, serum calcium and phosphorus) were collected from E2 group of cows. The measurements were made using automatic biochemical analyzer Cormay. The results were statistically analyzed and significant differences were determined by Student's test. Analysis of the results revealed the following: the expression of oestrus between 69.23% (E1 group) and 89.65% (E2 group); average intervals from treatment to first artificial insemination (1 IA) was between 5.53 ± 0.99 days (E2 group) and 8.66 ± 3.07 days, (E1 group); average intervals from treatment to conception was between 33.83 ± 12.05 days (E1 group) and 34.45 ± 10.22 days (E2 group); conception rate was between 46.15% (group E2) and 66.6% (E1 group). After estrus synchronization treatments with prostaglandin (PG)F2α the cows of group E2, with normal values of biochemical parameters had a higher conception rate, compared to cows with abnormal biochemical parameters (72, 72% vs 26.66%, P <0.01).
