Two experiments were conducted to evaluate the effects of dietary essential amino acid fortification on the growth performance of finishing pigs at a high ambient temperature. In Experiment 1, finishing pigs were randomly allotted to two dietary regimens (100% vs 200% of lysine requirement) and fed in a different ambient temperature (AT:22°C vs 32°C) for 4 weeks. In Experiment 2, finishing pigs were randomly allotted to 4 treatments, and fed 100% of lysine requirement diet (32°C-L100), 200% of lysine requirement diet (32°C-L200) and 200% of lysine requirement diet supplemented with threonine and methionine to meet the ideal pattern of essential amino acid (32°C-LTM) in 32°C AT, and 100% of lysine requirement diet in 22°C AT (22°C-L100). In both experiments, free amino acid concentrations of plasma were determined at weeks 0 (the day before heat exposure), 2, and 4 (the day before the end of the experiment). In Experiment 1, average daily feed intake were tend to decrease in pigs reared 32°C AT, there is no significant effect of AT on average daily gain and feed efficiency. Plasma free lysine concentration were increased in pigs fed 200% lysine diet. Significant lower concentration of plasma free lysine, threonine and methionine were observed in pigs reared in 32°C AT. In Experiment 2, daily body weight gain of 32°C-L200 treatment group was lower than 22°C-L100 treatment group. Treatment did not have any effect on average daily feed intake and feed efficiency. Plasma free lysine concentration were significantly higher in 32°C-L200 and 32°C-LTM treatment groups, and threonine and methionine concentration was higher in 32°C-LTM treatment group. These results indicate that supplementation of lysine, or mixture of lysine, threonine and methionine does not alleviate the negative effect of constant heat stress of finishing pigs.

To better understand the extent of artificial insemination usage in pig farms in Japan, we surveyed farms for application of artificial insemination technologies such as semen collection, sperm preservation, estrus detection, and insemination. The survey was performed using e-mail or fax contact details from the Japan Pork Producers Association website. The survey questionnaires were delivered to 834 farms and 19.4% (163 farms) responded;43.0% (70/163 farms) used only artificial insemination and 49.7% (81/163 farms) used both artificial insemination and natural mating. The rate of use of artificial insemination increased with the number of sows on the farm (P<0.05). The number of breeding sows per boar was 32.9 (73,218/2,223, 162 farms). Semen was collected using rubber or nitrile rubber gloves, which have an adverse effect on sperm motility and viability, in 56.6% of farms (56/99). Although catheters for post-cervical insemination were used in 44.8% of farms (64/143), the sperm counts and semen volumes for post-cervical insemination did not change compared with conventional insemination methods. Hormonal treatments for weaned sows were performed in 33.3% of farms (55/150);in most cases, a single dose administration of gonadotropin was used. This survey showed that artificial insemination use is increasing in large pig farms in Japan. Although new technologies such as post-cervical insemination have been introduced, their benefits have not yet been fully realized. Artificial insemination in Japan will progress further by introducing new technologies.