title: Factors affecting the success of resynchronization protocols with or without progesterone supplementation in dairy cows.
abstract: The objective of this study was to investigate factors that influence the success of resynchronization protocols for bovines with and without progesterone supplementation. Cow synchronized and not found pregnant were randomly assigned to two resynchronization protocols: ovsynch without progesterone (P4) supplementation (n = 66) or with exogenous P4 administered from Days 0 to 7 (n = 67). Progesterone levels were measured on Days 0 and 7 of these protocols as well as 4 and 5 days post-insemination. Progesterone supplementation raised the P4 levels on Day 7 (p < 0.05), but had no overall effect on resynchronization rates (RRs) or pregnancy per artificial insemination (P/AI). However, cows with Body Condition Score (BCS) > 3.5 had increased P/AI values while cows with BCS < 2.75 had decreased P/AI rates after P4 supplementation. Primiparous cows had higher P4 values on Day 7 than pluriparous animals (p = 0.04) and tended to have higher RRs (p = 0.06). Results of this study indicate that progesterone supplementation in resynchronization protocols has minimal effects on outcomes. Parity had an effect on the levels of circulating progesterone at initiation of the protocol, which in turn influenced the RR.
authors.affiliation: Clinic for Cattle, University of Veterinary Medicine Hanover, 30173 Hanover, Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Forro
authors.forename: Georgios
authors.initials: G
authors.lastname: Tsousis
authors.forename: Nicola
authors.initials: N
authors.lastname: Beindorff
authors.forename: Ahmad Reza
authors.initials: AR
authors.lastname: Sharifi
authors.forename: Christos
authors.initials: C
authors.lastname: Brozos
authors.forename: Heinrich
authors.initials: H
authors.lastname: Bollwein
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D015237:Dinoprost / Q000008:administration & dosage / Q000494:pharmacology*; D004973:Estrus Synchronization / Q000187:drug effects* / Q000379:methods; D005260:Female; D005299:Fertility Agents / Q000008:administration & dosage / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D007315:Insemination, Artificial / Q000662:veterinary; D010060:Ovulation / Q000187:drug effects; D011247:Pregnancy; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology*; D014325:Tromethamine / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D005299:Fertility Agents; D014325:Tromethamine; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D015237:Dinoprost
keywords: ovsynch; progesterone; resynchronization