Synchronization and Resynchronization as a Novel Approach for Improving Reproductive Performance of Postpartum Dairy Cows

Shahzad A. H., Sattar A., Husnain A., Ahmad I., Ahmad N., Nak D., ...More

PAKISTAN JOURNAL OF ZOOLOGY, vol.51, no.2, pp.511-520, 2019 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 51 Issue: 2
  • Publication Date: 2019
  • Doi Number: 10.17582/journal.pjz/2019.51.2.511.520
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.511-520
  • Keywords: Postpartum cows, CIDR-EB based synchronization, Progesterone profile, Reproductive management, Pregnancy rate, TIMED-AI, SUPPLEMENTAL PROGESTERONE, ARTIFICIAL-INSEMINATION, EMBRYONIC DEATH, PREGNANCY RATES, ESTROUS-CYCLE, OVULATION, FERTILITY, ESTRUS, CATTLE
  • Bursa Uludag University Affiliated: Yes


Estrus synchronization and suitable resynchronization intervention is crucial part of improved reproductive management in dairy industry. Our objectives were to appraise CIDR-EB based estrus synchronization and used CIDR-Ovsynch based resynch protocol in lactating Holstein cows at two different geographical locations. On location A, 160 postpartum cows were enrolled in standard CIDR-EB protocol. Cows were subjected to timed AI and randomly assigned into two groups: 1) control (n=70), subjected to AI on detected estrus (AIDE) from d18-d30 post TAI. Pregnancy rate was diagnosed on d30, d60 and d90 post TAI, 2) resynch (n=90) received CIDR from d14-d21 post TAI. On day 23, all cows received GnRH shot and open cows received remaining Ovsynch protocol. Blood was collected on d14,d16 and d30 for P4 profile. Cross-sectional area of luteal tissue was measured on d30 in pregnant animals in both groups. In experiment II, both control (n=64) and resynch (n=54) groups were similarly treated as in experiment I, without P4 profile and luteal cross-sectional area measurement. Pregnancy rate(PR) was compared by PROC FREQ of SAS. Effect of treatment on circulatory P4 profile and luteal tissue cross-sectional area were analyzed using GLM procedures (P<0.05). The PR on d30 in control (43%) and resynch (48%) groups was non-significant. On d60 and d90 overall PR was 44 and 73% (P=0.002) and 43 and 72% (P=0.002) while overall pregnancy loss was 11 and 4 /0 in control and resynch groups, respectively. In experiment II, PR on d30, d60 and d90 was 44 versus 54% (P=0.28), 53 versus 72% (P=0.03) and 50 versus 70% (P=0.025) in control and resynch groups with overall pregnancy loss of 14 and 3%. Mean P4 profile (ng/mL) was non-significant on d14 while significant on d16 and d30 post TAI in control and resynch groups. Mean luteal cross-sectional area on d30 post TAI has significant difference between both groups. In conclusion, a significant increase in overall PR in resynch group makes it an efficient reproductive management tool in comparison with control group.