title: Effect of body condition on reproductive efficiency of lactating dairy cows receiving a timed insemination.
abstract: Body condition may influence pregnancy rates to a timed insemination (Ovsynch/TAI) protocol and affect the economical performance of dairy farms. The objectives were to compare pregnancy rates using the Ovsynch/TAI protocol for the first service of lactating dairy cows with body condition scores < 2.5 (scale: 1 to 5, low BCS group) versus > or = 2.5 (control group) and to estimate the economic impact of the effect of body condition on reproductive performance. At 63 +/- 3 d post partum, cows were assigned to 2 experimental groups (low BCS = 81; control = 126), and were treated with GnRH at d 0 and with PGF2alpha 7 d later. At 48 h after PGF2alpha, cows received an injection of GnRH and were inseminated 16 h later. Pregnancy rates to the Ovsynch/TAI protocol were lower for the low BCS group than for the control group at 27 d (18.1 +/- 6.1% < 33.8 +/- 4.5%; P<0.02) and at 45 d (11.1 +/- 5.4% < 25.6 +/- 4.1%; P<0.02) after insemination. Economic analysis indicated that reducing the percentage of the herd in low body condition increases net revenues per cow per year. Body condition influenced pregnancy rates to the Ovsynch/TAI protocol.
authors.affiliation: Department of Dairy and Poultry Sciences, University of Florida, Gainesville 32611, USA.
authors.forename: F
authors.initials: F
authors.lastname: Moreira
authors.forename: C
authors.initials: C
authors.lastname: Risco
authors.forename: M F
authors.initials: MF
authors.lastname: Pires
authors.forename: J D
authors.initials: JD
authors.lastname: Ambrose
authors.forename: M
authors.initials: M
authors.lastname: Drost
authors.forename: M
authors.initials: M
authors.lastname: DeLorenzo
authors.forename: W W
authors.initials: WW
authors.lastname: Thatcher
mesh_terms: D000273:Adipose Tissue; D000818:Animals; D001823:Body Composition; D002417:Cattle / Q000502:physiology*; D015237:Dinoprost / Q000008:administration & dosage; D004972:Estrus Detection; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary*; D007774:Lactation; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D013997:Time Factors
chemical_list: D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D015237:Dinoprost