The introduction of breeding pigs from a breeding farm to a commercial farm is generally carried out by the transportation of live animals. The objective of this study was to construct a system using the technique of embryo transfer (ET) for the introduction of breeding pigs with minimal risk of disease transmission and transportation cost. Blastocysts and expanded blastocysts from Duroc sows were collected at the National Livestock Breeding Center located in Fukushima Prefecture and were virified using the micro volume air cooling (MVAC) method without direct contact with liquid nitrogen (LN). After cryopreservation, the embryos were put in the LN container and transported to Saga Prefectural Livestock Experiment Station. As the basic solution for cryopreservation (vitrification solution con taining 6.0M ethylene glycol , 0.6 M trehalose and 2% (w/v) polyethylene glycol and warming and dilition solution containing 1.8 M ethylene glycol and 0.3 M trehalose), 20 mM Hepes buffered porcine zygote medium (PZM)-5 or porcine blastocyst medium (PBM) was used. Warming vitrified embryos was transferred surgically and pregnancy results after the transfer was investigated. When PBM was used as a basic solution for vitrification of expanded blastocysts, the litter size (5.3±0.9) and the efficiency of piglet production (35.6%;percentage of number of piglets born based on the number of embryos transferred) of requesting it as ratio of to number of transplant embryos were higher (P<0.05) than those using PZM-5 (2.7±0.3 and 14.8%). The results demonstrated that PBM was superior to PZM-5 as a basic solution of vitrification of porcine expanded blastocysts by the MVAC method. Even in the use of PBM, the efficiency of piglet production after transfer of vitrified blastocysts (14.3%) was lower (P<0.05) than that of the expanded blastocysts. However, the zona pellucida of blastocysts is thicker than that of expanded blastocysts and may be prevented from being damaged as the processes of vitrification and warming. Thus, considering the reduction of the risk of disease transmission, the use of blastocysts on embryo transfer may be effective for the introduction and production of breeding pigs.

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The objectives of this study were to characterize swine herds that had a low retention rate by parity 3 (LRR herds) in terms of gilt development and lifetime reproductive performance and to examine management factors associated with low retention of females. The retention rate by parity 3 was defined as the number of females first-mated and successfully reaching the third parity. Questionnaires were sent to 115 herds that use the same recording system requesting information about gilt development and herd management procedures in 2008:(1) whether or not there was restricted feeding for pre-pubertal gilts;(2) type of gilt development diet;and (3) percentage of home-grown gilts in the herd. Data of 81 completed questionnaires (70.4%) and herd productivity measurements were coordinated with the performance data of 15,678 gilts that entered into those herds in 2008. Herds were categorized into LRR herds and ordinary herds on the basis of the lower 25th percentile of retention rate by parity 3 (71.6%). Herd level analysis showed that the LRR herds had 3.4% lower farrowing rates and 7.7% higher culling rates than ordinary herds (P<0.05). In addition, more LRR herds used restricted feeding and a gestation diet than ordinary herds (P<0.05). Furthermore, LRR herds had 29.2% higher percentage of home-grown gilts in their herds than ordinary herds (P<0.05). Individual female level analysis showed that first-mated females in LRR herds had 6.2-11.2% higher culling risk by parity 1-3 for reproductive failure than those in ordinary herds (P<0.05). However, no difference was found between the herd groups for lifetime average pigs weaned (P＝0.79). In a multilevel proportional hazard model, the hazard of culling for a female was associated with the restricted feeding and higher percentage of home-grown gilts in their herds (P<0.05), but not with the types of gilt development diet (P＝0.21). The survival probabilities at 60 weeks from first-mating were 80.1 and 84.1% for females that had restricted and unrestricted feeding as pre-pubertal gilts, respectively. In conclusion, too much restricted feeding during pre-pubertal periods is not recommended to improve female longevity. Additionally, strict selection procedures for reproductive soundness are recommended for home-grown gilts on entry to their herds.

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The aim of this study was to clarify whether all of corn contained in diet for finishing pigs could be replaced by brown rice without hindering growth performance and quality of pork and to elucidate appropriate ratios of brown rice and sweet potato when both of them are contained in a diet for finishing pigs. In the experiment 1, we replaced all of corn contained in a diet, the ratio of corn was 75%, with brown rice. Live weight gains, feed intake, and feed efficiencies were not affected by the replacement. In the experiment 2, diets contained both brown rice and sweet potato were given to finishing pigs. There were four levels of ratios of brown rice, 0, 30, 52.5, and 75%, while those of sweet potato were 0, 22.5, 22.5, 0%, respectively. Live weight gains and feed intake were not affected by the diets. Feed efficiencies were tended to be affected (P<0.10);the average feed efficiencies of pigs given the diet contained 30% of brown rice and 22.5% of sweet potato were the lowest whereas feed efficiencies did not differ among the other three groups. In order to increase the amount of brown rice given to a pig, pigs were given diets contained 52.5% of brown rice from 30kg to 120kg in the experiment 3. When these pigs reached to the finisher period (70kg), they were also given sweet potato (22.5%) together with brown rice. Feed intake during the grower period and that of during the overall trial were higher in the pigs given both brown rice and sweet potato (P<0.05). Further, feed efficiencies during the overall trial were lower in those pigs (P<0.05). However, growth performances were not affected by the diets during the finisher period. Throughout the three experiments, feeding brown rice increased total ratios of saturated fatty acids and those of mono-unsaturated fatty acids of inner layer of subcutaneous fat while it decreased those of poly-unsaturated fatty acids. In particular, increases in ratios of oleic acid and decreases in ratios of linoleic acid were highly reproducible. Although melting points of inner layer of subcutaneous fat were higher in pigs given brown rice in the experiment 2, feeding brown rice did not affect them in the experiments 1 and 3. Feeding brown rice and feeding both brown rice and sweet potato did not affect drip losses and shear force values of longissimus dorsi muscle throughout the three experiments. In conclusion, there won’t be any major problems of growth performances and qualities of pork even though all of corn contained in diet for finishing pigs is replaced by brown rice. We also conclude that appropriate ratios of brown rice and sweet potato when both of them are contained in a diet for finishing pigs were approximately 50% and 20 to 25%, respectively.

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