OCCURRENCE AND CHARACTERISTICS OF UNSUCCESSFUL NURSINGS IN MINIPIGS DURING THE FIRST WEEK OF LIFE

This study analyzes the time schedule of nursing in miniature pigs and describes some characteristics of successful nursings (with milk ejec tion) and unsuccessful nursings (without milk ejection). Nine sows wer e observed during the first 7 days post-partum. Individual sows showed marked consistency in the lengths of intervals between successful nur sings over periods of several hours. Analysis of bout lengths showed t hat in four sows a significant change in this interval occurred on day 1. Of all nursings (n = 473), 19% did not involve milk ejection. Two types of unsuccessful nursing were distinguished: unsuccessful nursing terminated by the piglets and unsuccessful nursing terminated by the sow. Both types were equally common throughout the 7 days of observati on. They were more common during periods when the interval between suc cessive nursings with milk ejection was relatively long. Both types di ffered mainly in the duration of massage. Duration of massage was cons iderably longer during unsuccessful nursings terminated by the piglets (median 11.0 min) than during successful nursings (median 5.7 min). T he duration of massage during unsuccessful nursings terminated by the sow was 3.0 min. Unsuccessful nursings seem to be a normal behaviour p attern with an adaptive 'function'. The use of the term 'unsuccessful' is therefore probably inappropriate. It is suggested that unsuccessfu l nursings may serve to decrease intervals between nursings, help to r egulate milk production, or both. Experimental work is needed to clari fy causation and function of unsuccessful nursings in pigs.