Background: The repeat breeding syndrome is the major cause
of low conception rate in zebu cows. A repeat breeder is generally defined as
any cow that has a normal estrus cycle, is free from any palpable
abnormalities, shows no abnormal vaginal discharges and has not conceived after
three or more successive services.
Aims: The study involved sixty dairy cows aimed at
identifying causes of repeat breeding syndrome, assessing the responses to
three hormonal protocols, and evaluating conception rates following natural and
artificial insemination.
Methodology: The study was conducted at Dairy Castle Farm in
Birol, Dinajpur, from June 2018 to May 2019. Three protocols—Select synch,
Ovsynch, and PGF2α plus PGF2α—were administered based on rectal palpation findings.
Estrus was detected via visual signs and vaginal electrical resistance thrice
daily. Cows in estrus were inseminated by Artificial Insemination and natural
service. Pregnancy was confirmed by non-return to estrus within 21 days and
rectal palpation at 90 days post-insemination. Estrus response, onset/duration,
and conception rate were compared using ANOVA and Chi-square test, with
significance set at P<0.05).
Results: Among all the experimental cows, 54.72% of cows
were diagnosed with cystic ovarian degeneration. The cows of the farm were also
diagnosed with 9.43% hypertrophied ovaries, 7.55% inactive (small rudimentary),
5.66% anovulatory heat, 1.89% fibrosis ovary and 1.89% corrugated ovaries.
Oestrous response rates were high across all protocols: 100% for Select synch
and Ovsynch, and 89.47% for PGF2α plus PGF2α. The mean onset of estrus was
similar among groups: 49 ± 3.41 hours for Select synch, 48.6 ± 2.98 hours for
Ovsynch, and 44.26 ± 15.8 hours for PGF2α plus PGF2α, with no significant
differences observed. Duration of estrus also showed no significant
differences, values of 40.1 ± 3.85 hours for Select synch, 47.1 ± 5.61 hours
for Ovsynch, and 37.5 ± 13.44 hours for PGF2α plus PGF2α. The conception rates
following induction of estrus by Select synch (GnRH+PGF2α) protocol, Ovsynch
(GnRH+PGF2α+GnRH) and PGF2α plus PGF2α protocol in dairy cows served naturally
used in this experiment were 100%. It can be concluded that hormonal treatments
may be effectively used for improving conception rates in repeat breeder dairy
cows.
Conclusion: Hormonal protocols effectively synchronised
estrus in Repeat Breeding Syndrome (RBS) cows. Conception rates via artificial
insemination remained critically low (8%) while natural service achieved 100%
conception. To improve reproductive and breeding system (RBS) management, it is
essential to ensure strict semen quality control during storage and transport,
provide thorough training for artificial insemination (AI) technicians in
proper insemination techniques and timing, and prioritise natural service in
areas where AI infrastructure is inadequate.
Author(s) Details
Parama Singha
Livestock Research Institute, Mohakhali, Dhaka, Bangladesh.
Md. Faruk Islam
Department of Medicine, Surgery and Obstetrics, Hajee Mohammad Danesh
Science and Technology University, Dinajpur 5200, Bangladesh.
Md Shanto Hossain
Department of Medicine, Surgery and Obstetrics, Hajee Mohammad Danesh
Science and Technology University, Dinajpur 5200, Bangladesh.
Tanvir Asifa
Department of Medicine, Surgery and Obstetrics, Hajee Mohammad Danesh
Science and Technology University, Dinajpur 5200, Bangladesh.
Md Samiul Tousif
Department of Medicine, Surgery and Obstetrics, Hajee Mohammad Danesh
Science and Technology University, Dinajpur 5200, Bangladesh.
Khaja Nafis Hasan
Billah Nabil
Department of Medicine, Surgery and Obstetrics, Hajee Mohammad Danesh
Science and Technology University, Dinajpur 5200, Bangladesh.
Omaiya Azam Oishi
Department of Medicine, Surgery and Obstetrics, Hajee Mohammad Danesh
Science and Technology University, Dinajpur 5200, Bangladesh.
Sourav Adhikary
Department of Medicine, Surgery and Obstetrics, Hajee Mohammad Danesh
Science and Technology University, Dinajpur 5200, Bangladesh.
Begum Fatema Zohara
Department of Medicine, Surgery and Obstetrics, Hajee Mohammad Danesh
Science and Technology University, Dinajpur 5200, Bangladesh.
Please see the book here :- https://doi.org/10.9734/bpi/rpbs/v7/6302
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