| dc.description.abstract | Prolonged oestrus is a reproductive disorder in cows that have a normal
estrous cycle but have a longed estrus duration of more than 36 hours, although
ovulation is still followed afterwards. The result of prolonged oestrus is a
discrepancy between the implementation of artificial insemination during the estrus
period and the time of ovulation, which results in fertilization failure and a decrease
in reproductive efficiency, which is characterized by the occurrence of repeat
breeding (RB), high service per conception (S/C), and long calving intervals (CI).
The case of prolonged oestrus in cattle is caused by an increase in preovulatory
progesterone (P₄) concentrations, which results in inhibition of the preovulatory
luteinizing hormone (LH) surge, which causes the duration of the estrous period to
be long. The high concentration of progesterone provides negative feedback to the
hypothalamus and hypophysis, which results in a low concentration of LH, which
causes a preovulatory LH surge that inhibits ovulation. One way that can be used
to increase the concentration of the LH hormone is by injecting the hormone hCG
(human chorionic gonadotropin). The hCG hormone has the same power as LH by
increasing preovulatory LH concentrations in cows with problems with pregnancy
and increasing the success rate of pregnancy. Therefore, this study was conducted
to analyze the effectiveness of hCG hormone administration in simmental
crossbreed cattle experiencing prolonged oestrus by identifying estrous features,
time of ovulation, ovarian dynamics, and analysis of P4 and LH hormone
concentrations, as well as successful fertilization after artificial insemination.
Four simmental crossbreed cows that experienced prolonged oestrus in
Ogan Komering Ulu Timur Regency, South Sumatra, were used as research
animals. Observations were made during the initial estrous period of the study
(control cows) and in the next estrous period after being given hCG (treated cows).
Parameters observed in control and treated cows were estrus intensity, estrus cycle,
and duration of estrus, ovarian dynamics and dominant follicle diameter (FD). The
treated cows were given an injection of hCG of 1500 IU/cow through the jugular
vein (IV) ± 12 hours after signs of estrus were observed or shortly after the
implementation of artificial insemination (AI). Examination of the success of
fertilization followed by pregnancy using the rectal palpation method was carried
out on the 90th day after IB. P4 and LH hormone testing was carried out by the
ELISA method using a commercial kit from DRG International Inc., Germany. The
collected data is presented using the mean ± SD calculation, while the qualitative
data is presented descriptively. The statistical analysis of the data used a paired
sample t-test with MS Office Excel 2016 and IBM SPSS Statistics 25 software.
The results of the study in control cattle showed that the peak of estrus
occurred 3.3±0.1 days after estrus, with a duration of 78 ± 12 hours of estrus and
54±12 hours of ovulation. Meanwhile, for cows treated with hCG, the peak of estrus
occurred on day 2.0±0, with a duration of 36 ± 0 hours of estrus and 24 ± 0 hours
of ovulation. An overview of the dynamics of the ovaries shows that the length of
the estrus cycle ranges from 22.3±0.5 days and has three follicular wave patterns in
one estrus cycle. The diameter of the dominant follicle in the control cow was
1.6±0.1 cm, while in the hCG-treated cow it was 1.5±0.1 cm. The concentrations of
the hormone progesterone P4 and LH during estrous periods in control cows were
6.40–14.60 ng/mL and 4.08–4.51 mIU/mL, respectively. In hCG-treated cows, the
concentrations of P4 and LH were 5.98–11.99 ng/mL and 5.10–5.16 mIU/mL,
respectively. It was concluded that IV administration of 1500 IU/cow of hCG
hormone increases LH concentrations during estrous periods, shortens estrus
duration and ovulation time, and increases fertilization success with pregnancy by
75%. The administration of hCG did not significantly affect the intensity of estrus,
the diameter of the dominant follicle, or the decrease in the concentration of the
hormone P4 during estrus in simmental crossbreed cattle that experienced
prolonged oestrus. | id |
