Necropsy-based study on dairy cow mortality-Underlying causes of death.

The worldwide problem of increasing dairy cow mortality is widespread in modern production systems, it causes economic losses, and indicates problems with herd health and welfare. Most studies on causes of dairy cow mortality are limited as they are based on secondary register data, or questionnaires for producers or veterinarians, and neither necropsies nor histopathologic analyses are usually performed. For this reason, no definite causes for dairy cow deaths have been determined making it difficult or impossible to implement effective preventive measures. The objectives of this study were to (1) determine the causes of on-farm mortality of Finnish dairy cows, (2) determine the usefulness of routine histopathologic analysis in bovine necropsies, and (3) assess how reliable producers' perception about the cause of death is. Underlying diagnoses of on-farm deaths were determined through necropsy of 319 dairy cows at an incineration plant. The necropsy data were combined with background information obtained from online questionnaires covering cow and herd records. Mastitis was the most common underlying diagnosis of death (26.6%), followed by digestive disorders (15.4%), other known disorders (13.8%), calving-associated disorders (12.2%), and locomotion disorders (11.9%). The underlying diagnoses of death varied during different stages of lactation and with parity. A large proportion of the study cows (46.7%) died during the first 30 d after calving, and of those, 63.6% died during the first 5 d. A routine histopathologic analysis was performed in every necropsy, and it changed the preliminary gross diagnosis in 18.2% of the cases. Producers' perception about the cause of death agreed with the necropsy-based underlying diagnosis of death in 42.8% of the cases. It was most consistent for mastitis, calving disorders, locomotion diseases, and accidents. In cases where producers had no insights about the cause of death, necropsy revealed the final underlying diagnosis in 88.2% of cases, demonstrating the usefulness of necropsy. Based on our findings, necropsies provide useful and reliable information to develop control programs for cow mortality. Including routine histopathologic analysis in necropsies, more accurate information may be obtained. Furthermore, targeting preventive measures on transitional cows may be most effective, as the number of deaths was highest at this time.

Disease recording systems and herd health schemes for production diseases.

Disease recording of cattle is compulsory in Sweden and Norway. Sweden and Denmark also have mandatory disease recording for swine, whereas Finland and Norway only have compulsory recording of infectious diseases. Both compulsory and voluntary systems are data based, the first ones developed in the 1970's. Disease recording at pig slaughtering is somewhat older. The veterinary practitioner, and often also the farmer, can report treated cases as well as fertility disturbances to the systems. Disease recording at slaughter is carried out by veterinarians and inspection officers. The data bases are handled by the veterinary authorities or the agricultural organisations in each country. Costs are defrayed by the authorities and/or the agricultural industry. The farmers receive periodic reports. Data are stored for three to ten years, often longer. Affiliation to animal health schemes for cattle or swine is voluntary. In Sweden and Denmark (cattle) they are run within the scope of government regulations. Affiliation to animal health programmes may also be demanded by organisations within the agricultural industry. These organisations are also responsible for the administration of the programmes. Costs to take part in herd health schemes are covered by the farmers them-selves. In certain cases, grants are received from agricultural organisations, authorities, or the European Union. Recording of diseases and the format of animal health schemes in the Nordic countries are described here in order to illustrate the possibilities to compare data between countries.

Characterization of clinical mastitis in primiparous heifers.

Using data from health records for cows in Finland from between 1983 and 1991, we investigated the general trend for frequency of mastitis in heifers, seasonal variation, breed differences, and etiology of the disease. The performance of the heifers was monitored during first lactation. Treatment of heifer mastitis, defined as mastitis treatment 1 wk before and 1 wk after calving, increased from 1.8 to 4.4% between 1983 and 1991. The increase can be partly attributed to increased milk production, subsequent reduced resistance to mastitis, and the general trend toward more efficient treatment of mastitis. Heifer mastitis was a characteristic disease of well-managed, productive herds with low SCC and a high frequency of mastitis treatments administered by a veterinarian. Of the feeding factors studied, only use of homemade concentrates was associated with higher mastitis frequency. Mastitic heifers had higher genetic potential for milk production than control heifers, but actual milk production was 70 to 80 kg lower than expected. Most mastitic heifers recovered well and were not more susceptible than control heifers to further incidence of mastitis or other diseases. However, heifer mastitis caused more heifers than usual to be culled.