Using 154 Large White sows that farrowed a litter of 8 or more piglets, we investigated the influences of litter size, farrow month, parity and gestation period on the time taken for a litter of all piglets to be born (designated as farrowing period). Also, the relations of the farrowing period to the rate of stillbirth, one-week weight and raising rate in piglets were studied.
Litter size made the farrowing period longer with a positive correlation (r=0.19, P<0.05), but farrow month, parity and gestation period did not influence the farrowing period.
The rate of stillbirth increased significantly (P<0.05) when the farrowing period exceeded 4 hours.
A significant difference in one-week weight of piglets was found in different farrowing periods (P<0.05), although there was no correlation between the farrowing period and the one-week weight.
No significant relation existed between the raising rate and farrowing period. In this study, it was shown that farrowing period was affected by the litter size. Furthermore, the present finding that prolongation of the farrowing period resulted in the increase of stillbirth rate suggests that its shortening within 4 hours can be a positive step to reduce stillbirth rate.

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In this experiment, we examined the effects of CP and TDN reduction on the growth, meat quality, and nitrogen excretion of eight fattening crossbred pigs (70-110kg). Two types of feed were prepared as follows : as a control, low-CP and standard-TDN feed (9.5%-75%) and as experimental feed, low-CP and low-TDN feed (9.5%-70%). Both of them were supplemented with lysine. They were formulated using the same ingredients and TDN decrease was induced by increasing the corn cob meal ratio in the feed. The animals were divided into the above-mentioned two groups having the same mean body weight. Experimental feeding was conducted in a temperature-controlled room at 25±2°C using a single cage with feed and water given ad libitum. Feed intake, water drinking, feces, and urea were determined every day. Body weight and body size were determined every week. Digestion trial was conducted in the last week. The loin area and backfat thickness at the starting point and end of experiment were determined using ultrasonic measurement. After slaughtering, carcass measurements and analyses of the chemical composition of the loin and the chemical character of the backfat were conducted. Furthermore the fecal and urinal nitrogen and ammonium gas generation density from these was determined.
It took 42 days to reach a mean body weight of 110 kg in both groups. While there was no significant difference in the daily body weight gain, feed intake, water drinking, feed efficiency, body size measurements, loin area obtained by ultrasonic measurement, and backfat thickness, feed intake and feces amount tended to increase in the experimental feed group. Digestibilities of CP, ether extracts, ADF, and calories in the experimental feed group showed significantly lower values than those in the control group and the DCP values in the experimental feed group were also significantly (P<0.05) lower than those in the control feed group. There was no significant difference in the results of carcass measurements, but the backfat thickness in the experimental feed group tended to be slightly thinner. Ether extract contents in loin also tended to decrease in the experimental feed group. Nitrogen contents in feces and urea tended to decrease in the experimental feed group, but the ammonium gas generation changed with a higher value in the experimental feed group.
Present results were concluded as follows ; the low-CP and low-TDN feeding did not reduce the growth and evaluation of carcass and it reduced the concentration of nitrogen in feces and urea, however it tended to consume more feed and excrete more feces and urea. Therefore a high absolute value of nitrogen was excreted in the low-CP and low-TDN feeding.

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An experiment was conducted to determine the effects of supplementing a reduced crude protein (CP) diet with dried orange juice pulp on the growth performance, back fat thickness, meat color and nitorogen excretion in finishing pigs (80 to 105 kg). The experimental diets were prepared as follows : a standard CP diet (standard CP diet, CP 15.6%), a low CP, amino-acid supplemented diet (low CP diet, CP 11.9%), low CP, amino-acid supplemented diets containing 10% or 20% of dried orange juice pulp (low orange 10% diet, CP 11.7% and low orange 20% diet, CP 11.5%), respectively. The experimental pigs fed in a group setting and kept with ad libitum feeding and drinking. Fecal and urinary nitrogen excretions were estimated by a digestibility trial using acid insoluble ash as a marker and by a method based on the Japanese Feeding Standard for Swine (1998), respectively.
The average daily gains for the standard CP, the low CP, the low orange 10% and the low orange 20% diet were 923, 959, 960 and 674g, respectively. The low orange 20% diet was significantly lower than the other diets (p<0.05). The average back fat thickness and meat color were not significantly different across the diets. Fecal nitrogen excretion for the standard CP, the low CP, the low orange 10% and the low orange 20% diet was 14.8, 15.8, 18.1 and 18.0 g, respectively. Urinary nitrogen excretion was 54.8, 38.2, 26.3 and 21.1 g, respectively. Total nitrogen excretion was 69.6, 53.7, 44.3 and 39.2 g, respectively, fecal nitrogen excretion for the low orange 10% and the low orange 20% diet was a little higher compared to the standard CP diet. Urinary and total nitrogen excretion for the low orange 10% and the low orange 20% diet were much lower than those for the standard CP diet.
These results suggested that a diet containing 10% of dried orange juice pulp to an amino acid-supplemented lower CP diet can reduce urinary and total nitrogen excretion without any detrimental effects on growth performance and meat color in finishing pigs.

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This study examined the relationship between real loin area and loin depth of a carcass that had been measured using image processing of carcass cross-sectional photographs. Thereby, we established a method of estimating the loin cross-sectional area from loin depth measured in live pigs using an ultrasonic device. First, we examined the relation between loin area (REM1/2) and loin depth at the position of a half body length. At that position, loin depth was measured at 2 cm, 4 cm, 6 cm, and 8 cm side from the midline (P2, P4, P6, and P8, respectively). Next, we examined the relations between the loin area (REMLAST) and the loin depth at the position of the last rib (LP4, LP6, LP8). The first examination used 149 Duroc pigs (103 castrates and 46 gilts). The second examination assessed 220 Duroc pigs (162 castrates and 58 gilts). Six trapezoid areas were calculated from the loin depth at the position of half body length : ((1) S1=(P2+P4)×2/2, (2) S2=(P4+P6)×2/2, (3) S3=(P6+P8)×2/2, (4) S4=S1+S2=P2+2P4+P6, (5) S5=S2+S3=P4+2P6+P8, (6) S6=S1+S2+S3=P2+2P4+2P6+P8). The coefficient of correlation between the carcass real loin area (REM1/2) and the live cross-sectional area (SEM1/2), as measured using an ultrasonic color machine, was 0.730 (p<0.001). The relationship between real loin area (REM1/2) and the real loin depth at 6 cm (P6) was highest (0.817, p<0.001) for the carcass loin at half body length. The relation with S5 (0.855, P<0.001) was the highest in six areas. Multiple regression analysis, of which the independent variables are depth and six areas, indicated this equation with the highest adjusted contribution (R²=0.764) : REM1/2=2.125S5-0.730P8-4.883. For the carcass loin area at the last rib, the relationship between the loin area and the depth at 8 cm from the midline (LP8) was highest (0.830, p<0.001) ; those with LP4 and LP6 were 0.604 (p<0.001) and 0.795 (p<0.001), respectively. When three depths of the last rib (LP4, LP6, LP8) were assumed as independent variables, the regression equation of EMLAST=1.104LP4+1.551LP6+3.757LP8+1.118, and an adjusted contribution of 0.724 was obtained. A regression equation of EMLAST=6.012LP6+0.913 and an adjusted contribution of 0.631 were obtained when we assumed LP6 as the independent variable considering live pig measurements.

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