DIFFERENCES IN CNS EXCITABILITY AND IN HA BITUATION OF PIGS OF HAMPSHIRE, LANDRACE, DUROC AND LARGE WHITE BREEDS

Individual excitability of CNS and habituation process in the new envi ronment of an experimental chamber (320 x 420 cm) were studied in 93 p igs of the Hampshire, Landrace, Duroc and Large White breeds. The beha vior of the pigs was recorded in 30-minute morning and afternoon habit uation tests at the age of three and six months at the live weight of 37 kg and 85 kg. The records involved: 1. locomotor activity (shown as grid-crossings, grids being drawn on the floor of the experimental ch amber), 2. voice signals and 3. elimination activities (defecation and urination). The results revealed differences between the breeds in CN S excitability and in the rate of habituation in the breeds under obse rvation. Habituation process was represented for all breeds (Figs. 1 a nd 2). During the four tests (morning and afternoon ones at the age of three and six months) locomotor activity, voice signals and eliminati on activities decrease in all breeds. Voice signals in the Hampshire b reed were an exception. Hampshire breed has the highest frequency of a ctivities related to excitability while Large White breed has the lowe st (Tab. I). Age differences in locomotor activity were significant (F ig. 1, Tabs. I to III) but they were not: found in the case of voice s ignals. As for differences between the sexes, the highest average valu es in locomotor activity were determined in the sows of Landrace breed (515 frequencies), the lowest values applied to the boars of Large Wh ite breed (265 frequencies). The frequency of voice signals in boars a nd sows is higher in all breeds than that of locomotor activity. Hamps hire sows had the highest average values of the frequency of voice sig nals (1 740 f). It was also shown that the frequency of voice signals in sows was higher than that of boars (Fig. 2, Tabs. II and V). The ev aluation of defecation indicator did not reveal any significant differ ences between the breeds. Some highly excitable individuals however ha d the high frequency of elimination activities (113 defecations). This is in agreement with the results reported by Hediger (1965), Meyer-Ho lzapfel (1960) and Veselovsky (1974) concerning the effect of stress i n the animals in zoological gardens and in the open nature on the incr eased frequency of defecation activities. Our results suggest the pote ntial use of habituation test for selection of breeds with optimum beh avioral characteristics for large herds and for the process of pig bre eding aimed at improvement of carcass value. Habituation test checked in our study can be used to determine the level of pig excitability. W e recommend to use mean and low excitation values.