Abstract:
Proc. Aust. Soc. Anim. Prod. (1978) 12: 247 THE IMPORTANCE OF THE COURTING BEHAVIOUR OF THE BOAR ON THE SUCCESS OF NATURAL AND ARTIFICIAL MATINGS P.H. HEMSWORTH, R.G. BEILHARZ and J.K. FINDLAY . The courting behaviour of the boar may have an important role in the success of the natural mating. The presence and activities of the courting boar appear to increase the uterine contractions of the sow (Docke and Worch, 1963; Pitkjanen, 1964). At a large Victorian commercial piggery two studies were conducted to examine the importance of the courting behaviour of the boar on the success of mating. In the first study the sexual behaviour of 24 breeding boars in three to five matings was compared with their conception rate record (number of sows farrowed/number mated). A significant correlation was. found between conception rate and the average number of times the boar nosed the sow's flank per mating (r = + 0.48, P < 0.05). The increased nosing activity by the boar during courting may stimulate the release of oxytocin, thereby increasing sperm transport, number of sperm reaching the oviductand the chances of fertilization. In the second study 68 sows were weaned from their piglets and housed for one week either singly in the boar house. On the second day of oestrus the (9 or in pairs (2 ? ) sows were either courted by a boar for 2 min. and then artificially inseminated (+d) or artificially inseminated (- 9). The 2~ + ti sows produced the greatest number of piglets born alive per 100 sow inseminations (Table 1). . We propose that social stress and/or stimulation by the boar are responsible for the variation in reproductive performance between the four groups. Social stress occurring when strange sows are mixed several days before mating (2 9) and when 'isolated' sows (v) were exposed to a courting boar may have reduced the reproductive performance of these sows, However, sows 2 v, which may have been more socially adapted than sows $ due to their housing treatment, may have responded to the stimulation of the courting boar and therefore improved their reproductive performance. These studies demonstrate that the sociosexual environment contains factors which either enhance or lower the fertility of the mating. DCC=, V.F. and WORCH, H. (1963) Zuchthyg. Bd. 7: 169. PITKJANEN, 1,G. (1964) Vth int, Congr, Anim. Rerod. AZ., Trento 6: 25, = Department of Agriculture and University of Melbourne, Animal Research Institute, Werribee, Vic. 3030. 247.
