Studies On Thermoregulatory Behaviour Of Erhualian Pigs

Erhualian pigs are famous for high reproductivity and good quality of meat. The behaviour thermoregulation of Erhualian pigs at different temperatures was investigated in comparison with Landrace and Yorkshire in order to explain the breed differences in heat tolerance. The study conducted in three parts.Part1: The thermoregulatory behaviours of boars of Erhualian, Landrace and Yorkshire were compared in order to explain breed differences in heat tolerance in April and May. For all pigs, the rectal temperature increased (P<0.01) as environmental temperature increased, but that of the Erhualian boars was consistently low. The time in quiet-standing activity of Erhualian (19.4±12.4min/h) was significantly longer than those of Landrace and Yorkshire (P<0.05).Part2: The change of thermoregulatory behaviour of boars of Erhualian, Landrace and Yorkshire in high temperature was investigated in order to analyze the characteristic of behaviour pattern. With the environment temperature at 27℃-34℃, the rectal temperatures of three breeds of boars all maintained below 39℃, with the differences between morning and afternoon temperature were 0.13, 0.03, 0.13℃ for Erhualian, Landrace and Yorkshire, respectively. The rates of lateral lying were 67, 63, 62%, respectively. Landrace and Yorkshire alternated in lateral lying and sternum lying. The rate of quite-standing of Erhualian was 16%, a unique characteristic for Erhualian pigs.Part3: The differences of rectal temperature, respiratory frequency and feed intake among Erhualian, Landrace and Yorkshire sows were estimated in order to evaluate Erhualian pigs' ability to adapt to high temperature. The feed intake, feed intake speed,...