Studies on Parturient Paresis with Special Reference to the Downer Cow Syndrome

Abstract

In addition to the classic form of parturient paresis characterized by hypocalcemia and somnolence, which responds rapidly to calcium therapy, it is not unusual to encounter other forms of this disease. The most common aberration would seem to be that in which the animals do not rise after calcium treatment. Many of these cows show little or no drowsiness, their appetite is often good, and the results of a clinical examination often negative. Some authors, Blood & Henderson (1960) for instance, consider that this “downer cow syndrome” is an indépendant disease not connected wiht milk fever.

Although the downer cow syndrome is a common disease and is of considerable significance, remarkably little has been written about it. Garm in 1950 noted that the frequency of downers had increased as compared with the numbers registered a few years earlier. He had also noticed that in many of these cows hypocalcemia was present on the first day of illness but not on subsequent days, despite the fact that they had marked signs of milk fever. Osinga, in an investigation in 1963, compared two types of milk fever: a typical form in which the cow is drowsy, lies on her side, and has partial anorexia, and an atypical form in which the animal is alert and has normal or only slight loss of appetite. Osinga remarked that the atypical cases had in-creased in number and suggested as an explanation the fact that the amount of protein in the fodder has increased, with the result that auto-intoxication and damage to parenchymatous organs may occur.

The object of the present investigation was to study the difference between cows that recover after treatment (“uncomplicated milk fever”) and those that have not risen 24 hrs. after the first treatment (“downers”). We also wanted to ascertain whether any changes occurred in the downers between the first and second, and second and third days. In addition, the difference between cows with blood-calcium levels equivalent to or over 8.0 mg/100 ml serum and those with corresponding values under 8.0 mg at the first examination was also studied.

Sammanfattning

Undersökningen omfattar 283 kor med paresis puerperalis. Av dessa tillfrisknade 184 eller 65 % efter en behandling. De övriga 99 blev långliggare och krävde ytterligare behandling. Vid klinisk och blodkemisk undersökning vid första undersökningstillfället kunde ingen skillnad påvisas mellan de kor som led av okomplicerad paresis puerperalis och de som blev långliggare. Vid jämförelse mellan förhållandena vid första undersökningstillfället och vid det andra hos långliggargruppen kunde tydliga ändringar påvisas. Medelvärdet för blodkalcium hade stigit från 5,9 till 7,3. GOT-värdet hade stigit från 167 till 336. Till tredje undersökningstillfället hade blodkalcium-värdet stigit till 8,9 och GOT till 841.

Undersökningsresultaten talar för att långliggarkomplexet är en komplikation till paresis puerperalis, och att muskelskador är en vanlig orsak till att korna blir långliggare.