Evaluation of ovsynch and cidr plus ovsynch protocols to improve reproductive efficiency in lactating dairy cows

Abstract

Appropriate postpartum reproductive management plays a vital role in dairy farm economics. Primary objective of the present study was to compare the efficiency of standard Ovsych protocol (OVP0) and its modified forms (OVP5 and OVP7) as postpartum reproductive management tools in cyclic dairy cows. In total, 167 Holstein cows were randomly divided into three treatment groups. The OVP0 group was comprised of 58 cows. Other two groups, OVP5 (n=55) and OVP7 (n=54), were similar to OVP0 except the intravaginal insertion of controlled internal drug release (CIDR) inserts for 5 or 7 days, respectively. Pregnancy was diagnosed using ultrasonography on d30, d60 and d90 post AI. Ovulatory follicle diameter was measured at timed AI and progesterone profile (ng/mL) on d30 and d60 post AI. Pregnancy rate was analyzed by Chi-square procedure while ovulatory follicle diameter and Progesterone profile by one way ANOVA (alpha=0.05). Ovulatory follicle diameter (Mean +/- SEM) was 15.19 +/- 0.17 (OVP0), 15.30 +/- 0.21 (OVP5) and 15.24 +/- 0.19 (OVP7), respectively. The P4 concentration has significant (P<0.05) difference among OVP0 (6.52 +/- 0.32), OVP5 (7.75 +/- 0.38) and OVP7 (7.58 +/- 0.26) on d30 post AI. This difference was non-significant (P > 0.05) on d60 post AI in OVP0 (6.37 +/- 0.49), OVP5 (6.75 +/- 0.36) and OVP7 (6.80 +/- 0.41), respectively. On d30 post AI, pregnancy rate was 39.70, 42.60 and 45.50% in OVP0, OVP5 and OVP7 groups, respectively (P=0.48). Corresponding pregnancy rate on d60 (P=0.39) and d90 (P=0.61) was 36.20, 32.80% in OVP0, 43.80, 41.80% in OVP5 and 37% in OVP7 group. Overall pregnancy loss was 17 (OVP0), 08 (OVP5) and 13% (OVP7), respectively (P=0.62). In conclusion, although pregnancy rate has non-significant difference among all three breeding protocols but numerically, improved pregnancy rate and reduced pregnancy loss was observed in OVP5 group.