Stillbirth and perinatal weak calf syndrome

Impacts of dairy cow nutrition precalving on calf health

This mini-review focuses on the effects of gestational dairy cow nutrition on calf health as mediated through colostrogenesis and calf immunity, morbidity, and mortality. The nutritional adequacy of the forage and supplementary diet and the metabolic status and body condition score of the dam can affect calf health. The mechanism of action of such impacts include maternal nutritional imbalances or deficiencies causing dyscolostrogenesis, nutritionally mediated calf ill health, and fetal programming impacts on calf health.

Influence of modifiable risk factors on the incidence of stillbirth/perinatal mortality in dairy cattle

Bovine perinatal mortality is defined as the death of a full-term calf before, during or up to 48 h after calving. Recent studies indicate that the prevalence of bovine perinatal mortality is increasing, particularly in Holstein primiparae. Factors leading to a greater incidence of dystocia are the most important modifiable variables influencing the risk of perinatal mortality. Modifiable predictors are largely (age at first calving, breeding method, sire, calving management, feto-maternal health status and gestational nutrition) or moderately (calf breed, sex, gestation length) under the control of the dairy farm manager. Unlike non-modifiable risk factors, such as primiparity and fetal plurality, these factors can be manipulated to reduce the incidence of perinatal mortality.

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.

Experimental reproduction of iodine deficiency in cattle

The role of iodine deficiency in stillbirth/perinatal weak calf syndrome was investigated in pregnant heifers. Five heifers were fed an iodine deficient diet (mean [sd] iodine concentration 0.06 [0.01] mg/kg dry matter [DM]) and six received an iodine sufficient diet (mean [sd] iodine concentration 1.45 [0.27] mg/kg DM). The diets consisted of wheat and soyabean meal with added minerals and vitamins (with or without iodine) and were fed to the heifers over the final four to five months of pregnancy. The iodine deficient diet produced clinicopathological changes and pathological changes in the thyroid glands of both the heifers and their offspring. However, all the calves in the iodine deficient group were born clinically normal.