Pig producers in Japan have been confronted in recent years with stagnant low market price of pork due to its overproduction and with competition with imported pork. In order to improve the efficiency of production under the competitive condition, pig producers are compelled to explore the appropriate scale of production and to adopt newly developed equipment and technology.
Our present study deals with the development of a computer program for simulating the pig production and cash and fund management in a pig farm. In order to evaluate the reality and accuracy of the simulation, actual data collected from a pig producer since September 1988 up to August 1989 have been compared with the simulated output.
Accumulated Error Rate (AER, %) which was defined as AER=Σ_i (Simulated valueactual value)/Σ_i (actual value)×100 [where i is the ith month.] and which represents the cumulative value of the ratio of the actual data to the difference between the actual data and the simulated output revealed that the number of weaned pigs per month was 1.62% in the first six months, but it was reduced into 0.13% after one year. Likewise, the comparison of the total number of marketed heads in terms of the AER was -0.10% in the first six months, and then it amounted to approx. 1%. Likewise, the AER in the heads in inventory amounted to the maximum as small as approx. 0.62%. The mean error rate in the monthly feed cost was approx. 5.8%, and the AER during one year amounted to a value as small as approx. 0.08%.
It could be thus realized that the above-mentioned program developed by the authors proved to be fully useful for planning cash-flow and fund schedule in the actual practice, because the program can indicate the monthly profit and loss to allow necessary fund raising and repayment for coming months on the basis of prediction of the production amount on a farm.

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In this study, comparative assessment was made of hardness of floor of pig stalls as a factor for occurrence of hoof and leg lesions and culling by Actinomyces pyogenes infection in pigs.
The pigs used were divided into 3 groups. The pigs in the first group were individually reared in stalls paved by concrete (hard floor), while those in the second group were in stalls paved by asphalt (soft floor) and the third group in a pen with concrete-paved floor and a paddock of soil space.
In each group, the occurrences of hoof and leg lesions, the cause of culling and titers of protease antibody produced by Actinomyces pyogenes were determined. The lesions and cullings of pigs were noted most frequently in the first group, followed by the second and the third groups. No relation could be found between protease antibody titer and floor hardness or exercises on the stall floor or paddock.

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This experiment was conducted in order to incite the spontaneous sucking behaviours of newborn piglets by two different artificial sucklers.
One type of the sucklers was made of sponge with its surface warmed by warm circulating water through a rubber tube. Within 30 minutes after birth, 56.5% of the piglets successfully sucked from the suckler. The average time required for starting to suck was 17.8 minutes after birth. However, some piglets were found to suspend their nosing behaviour.
The other suckler was made of a rubber bag containing warm water in it. The shaking movements of the bag by the contact of piglets stimulated the piglets for active nosing behaviour and 82.6% of them sucked from the suckler. The average time required for starting to suck was 10.3 minutes after birth.
The artificial teats used in this experiment incited mouthing and sucking reflexes of newborn piglets. The teats were so structured as to allow milk to flow in a natural manner. When the piglets mouthed the teats, they could invariably initiate the sucking with no subsequent interruption.
Stimulation of nosing behaviour and mouthing reflex of newborn piglets made it possible for them to suck the creep feed through the artificial sucklers.

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Differences in freezability of boar sperms were examined among the individual boars. In order to find the causes for the differences, the first experiment was conducted; sperms were collected from five different miniature boars and frozen and thawed to examine the differences in the freezability of the sperms among the boars. The freezability was evaluated by examining sperm viability and sperm index. The second experiment was conducted epididymal sperm from the boar which were slaughtered in abattoir were resuspended for 2 hours in the seminal plasma of five different boars and then frozen and thawed in order to examine the effect of seminal plasma on the freezability of boar sperms. In the third experiment, haemagglutinating activity of seminal plasma from five different boars was examined using red blood cells of pigs.
The following results were obtained.
1) Epididymal sperms resuspended in seminal plasma of five different boars showed freezability similar to that of each ejaculate from which the seminal plasma was obtained.
2) The higher the haemagglutinating activity, the lower was the freezability of the sperms.
The results of this study suggested that one of the main factors responsible for the freezability of boar sperms is derived from seminal plasma.
Proteins with haemagglutinating activity may be the possible cause.

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Increasing demands are being noted for miniature pigs in experimental uses as one of the large experimental animals as biomedical researches have made rapid progress in recent years. Our research project was initiated in 1978 at the Laboratory of Animal Reproduction in Kagoshima University. A boar and two sows of cross-bred strain of Ohmini miniature pig were introduced to the Laboratory and maintained therein as a closed group. Changes in the inbreeding coefficient, litter size, weaning rate, body weights, measurements of bodies, and characteristics of CLAWN miniature pigs were investigated in the meantime. The results were summarized as follows.
1. Six to seven generations were achieved in the piglets born up until 1989 since the introduction of the priginal crossbred pigs into our laboratory in 1978. The whole term of our investigation was roughly divided into 3 terms and the mean inbreeding coefficients of the 3 groups were checked to find that it was less then 12.5%, 28.2% and 41.4% in the first term (1978-1980), the second term (1981-1985) and the third term (1986-1989), respectively. The highest inbreeding coefficient shown by onf of them was as high as 57.0%.
2. The mean litter size was 5.0 (n=45) from among all the farrowings during the whole period of study. It wbs 5.7 in the first term and 4.7 in the third term, showing a decrease by one piglet. On the other hand, the differences in litter size by the season of farrowing revealed 5.5 in spring, 5.1 in summer, 5.0 in winter and 4.0 in fall. Tiis finding may suggest that the litter size was more influenced by seasons, especially by the mating in summar, than by the increase in the inbreeding coefficient.
3. The mean weaning rate was 78.0% during the whole period of study. It was reduced from 77.2% in the first term into 74.5% in the third term, a drop of 2.7%. By seasons of farrowing, the farrowing rate was 72.7%, 90.2%, 77.5% and 66.0% in spring, summer, fall and winter, respectively. The one in winter showed a sharp drop.
4. In terms of main measurements of bodies (body weights, lengths and body heights), the three measurements at birth were 0.55kg in males, and 0.50kg in females only weights bt birth, 20.5kg, 74.6cm and 39.5cm in males and 23.7kg, 74.7cm and 38.9cm in females at 6 months of age, 36.7kg, 88.6cm, and 47.9cm in males and 40.1kg, 87.3cm and 44.9cm in females at 12 months of age and 48.6kg, 100.2cm and 54.0cm in males and 58.1kg, 94.9cm and 51.5cm in females at age of 18 months.
5. CLAWN miniature pigs are mostly in white color, but some have black spots on the body. Totally black colored ones were noted in 13.7% of them during the whole period of our study. They are tame and meek.
It can be claimed that CLAWN miniature pigs have thus been established as an inbred strain of miniature pigs, as it is of a small size, white color and tame for easy handling. It is therefore hoped that it be subjected to propagation in a larger scale and effective uses.

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The effects of hemolysis rate and hemolysis severity of porcine blood which was collected by the normal method from pigs upon the measured values of biochemical constituents of porcine serum were evaluated, and the following results were obtained.
1. Evaluation of hemolysis severity
Of 74 serum samples collected from pigs of the same number, 15 samples (20.3%) had no hemolysis (-), 21 (39.2%) showed (±) hemolysis, 12 (16.2%) (+) hemolysis, 15 (20.3%) (_??_) hemolysis and 3 (4.0%) showed (_??_) hemolysis. Thus, the samples with (+) or severer hemolysis accounted for approx. 40%.
2. Effects of hemolysis on measured values
1) Items in which neither overrating nor under-rating was caused by (±) hemolysis as compared with the non-hemolytic serum were TP (Total protein), serum protein fraction, BUN, ALP, GOT, GPT, LDH, LDH isozyme, Glu, T-cho, TG, PL, Fe, Ca, Mg and IP (inorganic phosphorus).
2) Item in which the measured values were significantly lower due to (+) or severer hemolysis as compared with that in non-hemolytic serum was LDH₁.
3) Items in which the measured values were significantly higher due to (_??_) or severer hemolysis as compared with that in non-hemolytic serum were LDH and LDH₅.
4) Items in which the measured values were significantly lower due to (_??_) hemolysis as compared with those in non-hemolytic serum were GOT, GPT, β-fraction and LDH₄.
5) Items in which the measured values were significantly lower due to (_??_) or severer hemolysis as compared with those in non-hemolytic serum were TG and PL.
6) Items in which neither overrating nor under-rating was caused by (_??_) hemolysis as compared with those of non-hemolytic serum were TP, serum protein fractions except β-fraction, A/G, BUN, ALP, LDH₂, LDH₃, Glu, T-cho, Fe, Ca, Mg and IP.

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In swine farms where improvement of productivity was thought to be hardly possible because of outbreaks of chronic diseases such as pneumonia, atrophic rhinitis, Aujeszky's diseases and diarrhea, Bifidus bacterial cell powder containing peptidoglycan, glycyrrhiza powder, garlic powder and plasma (serum) powder were supplemented to the swine feed, and improvements in productivity were observed in the pigs as described below.
1. Comparison between the supplemented feeding period and the non-supplemented feeding period, in the farms under consistent operation up to the usual finish:
1) The mean litter size in the non-supplemented feeding period for 3 months was 10.4 piglets, while that during the supplemented feeding period for 3 months was 11.3 piglets, which was larger by 0.9 piglet.
2) The mean quality of the dressed carcass during the non-supplemented feeding period for 3 months was 44.5%, while that during the supplemented feeding period for 3 months was 54.0%, which was higher by 9.5%.
3) When the cost of disease control borne for the non-supplemented feeding period for 3 months was regarded as 100%, the average cost for the supplemented feeding period for 3 months was 63.0%, which was less by 37.0%.
2. In the farms exclusive for finishing operation, the mortality in the supplemented feeding herd was 1.4%, which was 1/5.5 times lower than that of the non-supplemented feeding herd.

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