Lying behavior was examined on 5 groups of 2 sows fed in a pen. There was a concrete paddock (17 m²) attached to the pen (8 m²). Changes in lying behavior of sows fed in group (sows in group feeding) involved in different seasons were investigated at spring (temperature of pig house 8-19°C), summer (21-35°C), autumn (8-24°C) and winter (0-9°C). Frequency of lying behavior for a day was 11.1±4.3 times for summer, 10.6±2, 7 times for autumn, 9.4±3.2 times for spring and 6.3±2.7 times for winter (p<0.05). The longest duration of lying behavior for a day was 1.268±37 minutes in summer and followed by 1, 267±26 minutes for autumn, 1, 259±55 minutes for spring and 1, 206±52 minutes for winter, respectivly, which showed significant differences statistically (p<0.01). With respect to group lying behavior, the average percentage was 93.2±4.2% for winter, 85.6±7.7% for spring, 71.4±11.4% for autumn and 30.8±24.6% for summer (p<0.01). As seen from the above, frequency and duration for a day in lying behavior of sows fed in group (sows in group feeding) were decreased with fall in temperature of the pig house. Contrary to those results, the average percentage of group lying behavior was increased with low temperature of the pig house.

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It is well known that the periodic vocalizing grunt of sow during lactation induces the suckling behavior in the newborn pig. It is also reported that the piglet can distinguish the grunt of a sow. In this study, the characteristics of periodic grunts of a Landrace sow during lactation are examined and compared with respect to phonation hours, spectral analysis, formant frequency distribution, etc. The results showed that, the phonation interval during lactation showed a concave tendency. Phonation hour of the grunt was in the 100msec to 200msec ranges, and the phonation hour for each individual was almost constant. Grunting during lactation was divided into the initial stage, middle stage, and the final stage, the spectrum waveform of the grunt in each period was analyzed. The spectral variation in each period showed a very similar tendency. The primary formant was in the 450Hz to 700Hz ranges on the grunt from the analysis of the formant frequency, and the second formant was a distribution in the 1, 000Hz to 4, 000Hz ranges.

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We examined the viability of boar sperm, after liquid storage at 15°C, in which lipid peroxidation had occurred. Also the viability of sperm treated with ferrus sulfate, Ascorbic acid (VC) and hypotaurine (HT) were investigated. Boar semen collected from 11 boars was centrifuged and diluted with lipid peroxidation induction media which were made of Modena including 0.01, 0.1, 1mM ferrus sulfate and 0.5mM VC. The sperm concentration of the diluted semen was 3.0×10⁸/ml. Then the media were incubated at 37°C in air for 1 hour. Lipid peroxidation of sperm incubated with ferrus sulfate and VC was estimated by malonaldehyde (MDA) concentration. The incubated semen was stored at 15°C for up to 288 hours and the viability of sperm was examined. Additionally, MDA was measured in semen incubated with ferrus sulfate, VC and HT and incubated semen was stored at 15°C for up to 288 hours. Then the viability of the stored semen was also determined. The amount of generated MDA from sperm incubated with 0.1 or 1mM ferrus sulfate was significantly over sperm in which lipid peroxidation was not induced (P<0.001). After liquid storage for 48 hours, the viability of sperm induced lipid peroxidation significantly lower than that of non treated sperm (P<0.05). The viability of sperm treated with ferrus sulfate and HT was not significantly different compared with non treated sperm. However, the level of MDA from sperm incubated with HT was not significantly lower than sperm incubated without HT. These data indicate that lipid peroxidation occurred before liquid storage at 15°C and the viability of boar sperm decreases after storage. Thus the addition of HT into the medium to induce sperm lipid peroxidation would improve the viability of sperm after liquid storage at 15°C.

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