Risk factors for stillbirth in Holstein heifers under field conditions in France: a prospective survey.
Risk factors for stillbirth, defined as birth of a dead calf or a calf dead within 24 h after parturition, were studied in Holstein heifers. Data came from an overall 4-yr prospective survey conducted in French dairy herds. Only heifers that delivered a single calf were included in the study. The stillbirth incidence was 6.9%. The predictive indicators of stillbirth risk were: gestation length, prepartum body condition and dirtiness scores, biochemical and hematological blood parameters measured during the last 2 mo of gestation, and calving conditions. Multiple logistic regressions were run using herd, calving year, calving season, blood sampling-to-parturition interval, and body scoring-to-parturition interval as the fixed effects. The results, expressed as the ratio of the odds of disease occurrence in the exposed and non-exposed subgroups (OR), indicated that dystocia and a body condition score (BCS) higher than 4 before calving were significant risk factors for stillbirth (OR=14.6, P<0.0001 and OR=2.98, P<0.05, respectively). Prepartum circulating neutrophil counts higher than 1950/mm3 (OR=0.50, P<0.05) were associated with a lower risk of stillbirth. A higher occurrence of placental retention, lower fertility and a lower 305-d milk yield were significant consequences of stillbirth.
Chassagne
M
M
INRA, Unité de Recherches d'Ecopathologie, Centre de Clermont Ferrand-Theix, Saint-Genès Champanelle, France.
Barnouin
J
J
Chacornac
J P
JP
D000818:Animals; D001823:Body Composition; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology*; D004420:Dystocia / Q000662:veterinary; D005260:Female; D005313:Fetal Death / Q000453:epidemiology / Q000662:veterinary*; D005602:France; D007774:Lactation; D007958:Leukocyte Count; D016015:Logistic Models; D008297:Male; D009504:Neutrophils; D010298:Parity; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors