This study aimed to observe the effects of alteration in environmental temperature for a day on the growth and physiological responses of piglets. Experiments were conducted twice for the difference of parturition of brood boars in the three levels of integrated temperature (IT) which was calculated by the integration of environmental tempeture measured once an houre with respect to 24 hours and they were: 504°C (control: 21°C×24 hours), 600°C (21°C×16 hours+33°C×8 hours) and 696°C(21°C×8 hours+33°C×16 hours). Piglets used were crossbred of Y×YW and Y×L, their numbers were 6 and they were 40, 41, …, 45 days of age, respctively. Piglet was fed in a single cage under the controlled temperature, feeding was finished on the day when one of them reached 25kg of body weight. The body weight gain and feed intake, which were corrected for the initial body weight, were lowered with increasing IT (P<0.05). Feed conversion showed no difference among these IT groups, but the ratio of water intake to feed intake increased significantly (P<0.05) with the increasing IT. The physiological responses in body temperature, body surface temperature and respiration rate showed no difference in the same temperature among the different IT groups, but their values were apparently higher in 33°C period.
These results showed that the extension of exposure time to 33°C inhibits the growth of piglets under the assigned levels of IT in the present study.

View full abstract

The genetic variations of blood groups and biochemical polymorphisms in Min pigs, a Chinese pig breed, were investigated in this study as one of the attempts to clarify the genetic properties of the pig breed which is being brought into Japan in recent years. The blood samples were collected from sixteen animals (9 males and 7 females) of this breed which was maintained in Niigata Animal Husbandry Experiment Station. Blood types investigated comprised eight blood groups (A, E, F, G. H, K, L and O), five serum proteins (Tf, Pa, Hp, Cp and Am), five red cell enzymes (PHI, 6PGD, PGM, ADA and EsD) and two serum allotypes (PSA-I and PSA-II), 20 loci in total.
The results were as follows.
1) Min pigs showed polymorphic variations at A, E, F, G, H, K, L, O, Tf, Hp, 6PGD, PSA-I and PSA-II, while the other seven loci were found monomorphic. When the gene frequencies in Min pigs were compared with those in Jinhua, Meishan, Taoyuan, Short-ear and Ohmini pigs, those in Min pigs were characteristic in G, K, PSA-I, Tf, Hp and 6PGD loci. As a whole, Min pigs showed the distinctive character in blood types of Asian pigs.
2) The genetic variability of Min pigs revealed by gene homogeneity index (H. I.), expected proportion of heterozygosity per individual (H), proportion of polymorphic loci (P poly) and effective number of alleles per locus (Ne) was the second highest among the six Chinese pig breeds (Min, Jinhua, Meishan, Taoyuan, Short-ear and Ohmini). However, its variability was much lower than those of Euro-American pig breeds,
3) Using the gene frequencies at the 20 loci, the genetic distances between Min pigs and sixteen pig breeds were calculated on the basis of the formulae of ROGERS and NEI, and the dendrograms showing genetic similarities among seventeen pig populations were prepared. Min pigs showed similar close genetic distances to five Chinese native pigs and Göttingen miniature pigs, and the distances to Taoyuan and Jinhua were the closest. It was clarified from the dendrogram that Min pigs belonged to Asian pig group which was completely different from Euro-American group, and was situated at a short distance from Taoyuan, Ohmini, Jinhua and Meishan pigs like Short-ear breed.

View full abstract

A study was conducted to evaluate the efficacy of Altrenogest (AT), a synthetic progesterone, administered starting from proestrus or estrus (day 19 to day 2 of the estrous cycle, day o=the first day of estrus) or diestrus (day 3 to day 18) for estrous synchronization in swine. Forty-eight gilts and sows were given orally 20mg of AT per head per day.
In Trial I, 11 gilts given AT for 5-8 days starting from day 19-day 2 were slaughtered to examine ovarian changes. In Trial II, 37 gilts and sows were administered for 18 days to evaluate for estrous synchronization effect and fertility at the synchronized estrus.
The results obtained will be summerized as follows:
1) In Trial I, 10 of 11 gilts were not prevented for ovulation and normal corpora lutea were formed (14.1±3.1). Only one gilt of 5 treated AT starting from day 19-day 20 did not ovulated.
2) In Trial II, a group of 16 animals given AT treatrment starting from day 19-day 2 exhibited estrus in 93.8% (15/16), average interval from the secession of AT treatment to estrus being 6.1±1.0 days and average duration of estrus being 48.0±13.6 hours.
In the second group of 21 animals given AT treatment starting from day 3-day 18, figures for the same items were 95.2% (20/21), 6.1±1.2 days and 60.0±22.0 hours, respectively. Statistically, no significant differences were observed between these figures.
3) A comparison was made between two groups of animals fed AT starting from day 19-day 2 and from day 3-day 18 for number of animals with fertilized eggs, average number of corpora lutea per head and fertilization rate of recovered eggs (80.0% vs 85.7%, 15.7±3.5 vs 15.7±3.9 and 76.2% vs 76.1%, respectively). The differences between these pairs were insignificant.
The present results clearly show that AT may effectively be used for estrous synchronization in cyclic swine with irrespective of the estrous cycle.

View full abstract

Based on the data collected from forty six local hog farms in 1987, the factors affecting ordinary profit were analyzed. A total of twenty two factors were considered for each brood sow, including the ordinary profit, cost of goods sold, sales amount, the number of deliveries per year and unit price of dressed carcass.
We computed a multiple regression equation equation with forward selection method and obtained the following results.
Y=30, 129.204-0.952X₁+0.914X₂-0.527X₃-0.961X₄
R²=0.964 R²=0.961 Se=16, 792.1 d. f=41
where the response variable (Y) is the ordinary profit, and the explanatory variables are the cost of goods sold (X₁), the sales amount (X₂), the selling and administrative expense (X₃), and the non-operating expense (X₄).
Standardized regression coefficients on each variable were -1.127, 0.960, -0.377 and 0.260, respectively. It suggests that the cost of goods sold contributed more to the ordinary profit than the sales amount.
The cost of goods sold consisted mainly of feeder livestock cost and feed cost. Standardized regression coefficient on the feeder livestock cost was 0.521 and on the feed cost was 0.486. The sales amount consisted mainly of the unit price of dressed carcass and the number of deliveries per year. Standardized regression coefficient on the unit price of dressed carcass was 0.489 and on the number of deliveries per year was 0.270.
These coefficients proved the number of deliveries per year, the marketing techniques to meet the market conditions, and the feeder livestock cost and the feed cost to be the most important factors for the improvement of ordinary profit.

View full abstract

The differences of intramuscular lipid compositions in Large White (W), Berkshire (B) and Duroc (D) breeds fattened up to 90kg were studied. The Intramuscular lipids were extracted from M. longissimus thoracis, M. biceps femoris and M. semimembranosus which taken from three barrows and three gilts of each three breeds above and were separated by high-performance thin-layer chromatography. The standard lipids which used for drawing up the calibration curves were developed on the same thin-layer plates simultaneously with intramuscular lipids. The lipid spots were visualized with 25% percloric acid and the areas of lipid spots were scaned with the Model CS-9000 dual wavelength flaying spot scanner (Shimadzu Co.). The lipid compositions were indicated by weight percentage.
The following results were obtained.
1) The detectable components in intramuscular lipid in present experiment were triacylglycerol (TG), free fatty acid (FFA), cholesterol (CH), phosphatidyl ethanolamine (PE), phosphatidyl choline (PC), sphingomyeline (SPM) and lysophosphatidyl choline (LPC).
2)The intramuscular lipids were composed of approx. 63-85% of TG, 10-23% of PC, 2.3-6.0% of PE, 1.3-3.3% of CH, 0.7-1.7% of SPM, 0.5-1.7% of FFA and 0.05-0.44% of SPM depending upon the type of muscle and breed.
3) The neutral lipid fraction (NL) was high in TG and in proportion from 92% to 98%. In the phospholipid fraction (FL), the predominant component was the PC followed by PE, both comprising from 92% to 94% of the PL.
4) Duroc breed, as compared with Large White and Berkshire, contained significantly higher NL and TG but less other components of lipids. In Large White and Berkshire, there were no remarkable differences in the composition of intramuscular lipids in M. biceps femoris and M. semimembranosus, but the proportion of TG in M. longissimus thoracis of Large White was significantly lower and the proportions of other components were relatively higher than those in Berkshire.
5) It was shown that the effects of breeds on the proportion of each component of PL to total PL were comparatively small.
On the basis of the findings mentioned above, it was suggested that the differences in the intramuscular lipid compositions among the different breeds depended on the fat deposited in muscles. It was also suggested that the differences among breeds in the proportion of the each component of PL were comparatively small.

View full abstract

The developmental process of the reproductive organs was morphologically and histologically investigated in Jinhua boars after birth. The testis greatly developed after 45 days of age. Spermatozoa were first found in the seminiferous tubules at approximately 75 days of age, when the histological composition of the seminiferous epithelium improved to a mature type. Epididymis grew rapidly after 45 days of age, and revealed a well-developed structure of the ductal epithelium in any region by 60-75 days of age. On the other hand, the weight of each accessory genital gland increased rapidly after 60 days of age. In the seminal vesicle, corpus prostatae and blubourethral gland, the terminal portions were well ramified and filled with PAS-positive secretions by 75-90, 90 and 30-45 days of age, respectively. These results indicate that Jinhua boars reach puberty as early as 75 days of age. It also appears that development of the reproductive organs occurs at an earlier age in Jinhua boars than in European and American breeds.

View full abstract

The experiment was conducted to assess the effect of fumaric acid supplementation on the performance of starter pigs and on the microbial population appearing in their feces. Seventy seven crossbred (LWD) piglets produced by 8 sows were weaned at 3 weeks of age and allotted to the control group of 39 head and the test group of 38 head. The weanling pigs fed a solid milk replacer for 2 weeks and a starter pig diet for 4 weeks. They were compared with pigs fed similar diets supplemented with 3% fumaric acid. During the 6-week feeding trial, supplementation of fumaric acid to the diets improved (p<0.01) weight gain. The average daily gain was 14% greater for pigs fed diets supplemented fumaric acid. Feed conversion efficiency also improved 6% but could not find statistical significance. There was no difference in viable counts of coli-form bacteria assayed in the feces of two groups, and no difference in those of fumaric acid-utilizing anaerobes. Gram staining of fumaric acid-utilizing anaerobes revealed that these microbes consisted of gram-negative small cocci and gram-negative large cocci. The former anaerobe produced large amount of propionic acid and small amount of acetic acid from fumaric acid in a liquid medium. On the other hand, the latter anaerobe produced various acids including acetic, propionic, isobutyric, butyric, isovaleric, valeric and caproic acids in the same medium. These findings suggested that the former shoud be Veillonella species and the latter Megasphaera species.

View full abstract