[Blood characteristics of some french pig populations. Relationships with the malignant hyperthermia syndrome (author's transl)].

Lactic acid, glucose, creatine phosphokinase (CPK) and some mineral components were determined in the blood of piglets before and after a halothane test of five minutes (only before for CPK). Two different experimental groups were studied: 222 Pietrain piglets from an INRA experimental herd, and 325 piglets from the Large White, French Landrace and Belgian Landrace breeds entering performance testing stations. Animals reacting positively to halothane ("MHS" piglets) have significantly higher blood levels of lactic acid and potassium before anesthesia than normal animals. CPK is also higher, except for the Belgian Landrace: in this breed CPK shows the same average value and distribution in the two groups of piglets (normal and MHS). There are also breed differences in blood magnesium, independently of the reaction to halothane. But the breed differences observed in lactic acid and CPK are related to the proportion of MHS piglets in each breed. Anesthesia by means of halothane lowers the measured blood characteristics--except for glucose--in normal animals, and rises them--except for potassium--in MHS piglets. The results are discussed in view of the incomplete discrimination between the two types of pigs, with a 5 minutes test, and, particularly, considering possible breed differences in that respect.