THE INCIDENCE OF DYSTOCIA IN DORSET HORN EWES

The incidence of dystocia was recorded in flocks of Dorset Horn ewes lambing in winter, spring or summer and grazed at 8, 12 or 16 ewes per hectare over a ten-year period. The mean incidence of dystocia was 34% of ewes lambing. Significantly more ewes experience a difficult birth at winter (35%) and spring (39%) than summer (26%) lambings. Neither stocking rates nor pre-lambing ewe bodyweight were related to the incidence of dystocia. The incidence of dystocia was significantly greater in 2-year-old ewes than in any other age group. Foetal size was of major importance in the occurrence of dystocia. Approximately 60% of single and twin born lambs that had birth weights greater than 4.5 kg had a difficult birth whereas in lambs weighing less than 3.2 kg only about 10% were affected. Thirty-six per cent of all perinatal mortality was attributable to dystocia. Approximately 27% of single and 73% of twin presentations in assisted births were abnormal, 31% of all lambs assisted had 1 or both legs retained, 4% had posterior (including breech) presentations and the remaining 8% were of varied forms of malpresentation. Significantly more single male than female lambs experienced a difficult birth and the mean birth weights of single, twin and triplet born lambs that had a difficult birth were greater than the birth weights of singles, twins and triplets born normally.     

Veränderungen der Muskelfasertypenverteilung im M. longissimus dorsi von Ebern während des Wachstums, dargestellt mit verschiedenen histochemischen Methoden

Changes in the distribution of muscle-fiber-types from the M. longissimus dorsi of male pigs. A Histochemical Approach Samples of the M. longissimus dorsi from growing up pigs were taken by a shooting-biopsy. The types of muscle-fibers could be demonstrated by two different histochemical staining procedures. With these two histochemical staining procedures significant differences between the different structure of the muscle-fibers during increasing age of the pigs could be detected.