title: Observed and expected combined effects of clinical mastitis and low body condition on pregnancy loss in dairy cows.
abstract: The objective was to compare the observed and expected combined effects of clinical mastitis before timed artificial insemination (TAI) and low body condition at 70 d postpartum (dpp) on pregnancy loss in dairy cows. Cows were examined for pregnancy by ultrasonographic examination 28-32 d after TAI; the presence of an embryo with a heartbeat was the criterion used to determine pregnancy. Cows diagnosed pregnant were re-examined by transrectal palpation of the uterus and its contents 28 d later to confirm pregnancy status and to identify pregnancy loss. Eighty-eight (17%) of 512 cows were diagnosed with pregnancy loss. Cows affected with clinical mastitis before insemination and a body condition score (BCS)≤2.75 at 70 dpp were 2.03 times more likely to experience pregnancy loss, compared to cows without clinical mastitis and with a BCS>2.75 (RR=2.03; 95% CI=1.15, 3.60; P=0.01). This observed combined effect for pregnancy loss (RR=2.03) was higher than the expected combined effect based on adding (RR=1.39) or multiplying (RR=1.42) absolute independent excesses due to clinical mastitis or low body condition.
authors.affiliation: Department of Large Animal Clinical Sciences, University of Florida, Gainesville, Florida, USA.
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Hernandez
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Risco
authors.forename: Fabio S
authors.initials: FS
authors.lastname: Lima
authors.forename: Jose E P
authors.initials: JE
authors.lastname: Santos
mesh_terms: D000034:Abortion, Veterinary / Q000209:etiology*; D000818:Animals; D001824:Body Constitution; D002417:Cattle; D003430:Cross-Sectional Studies; D005260:Female; D008414:Mastitis, Bovine / Q000150:complications*; D049590:Postpartum Period; D011247:Pregnancy; D012307:Risk Factors