• Korean Journal of Veterinary Research
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• v.39 no.6
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• pp.1161-1167
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• 1999

To investigate the effect of diazepam on fetal development in pregnant rats, this experiment was performed in eighty Sprague-Dawley female rats which were 8 weeks old and grouped into two according to different diazepam treatment period during 5-9 days of gestation and 10-14 days of gestation. Both experimental groups were included by saline treated groups (control) and diazepam-treated groups (6mg, 12mg and 24mg), respectively. Diazepam was injected to pregnant rats subcutaneously, which were sacrified on 20 days of gestation and mean litter size, fetal body weight, fetal crown-rump length (CRL) and pathological findings were examined. 1. Concerning mean litter size, diazepam-treated groups showed lower mean litter size than control in both 5-9 days and 10-14 days of gestation groups(p < 0.05) without difference according to dosage of diazepam and day of gestation. 2. Concerning fetal body weight, diazepam-treated groups during 5-9 days of gestation showed lower fetal body weight than control and the other treated group during 10-14 days(p < 0.01) without difference according to dosage of diazepam. Diazepam-treated group during 10-14 days of gestation showed no difference among experimented groups. 3. Concerning fetal crown-rump length (CRL), diazepam-treated groups during 5-9 days of gestation showed shorter CRL than control and the other treated group during 10-14 days of gestation(p < 0.01) without difference according to dosage of diazepam. 4. Reduction of mean litter size, fetal body weight and CRL was shown from when treated by the dosage of 6mg/kg of diazepam. 5. Maternal mortality according to dosage of the 20mg/kg of diazepam were 30% and 20% in the treated group during 5-9 days and 10-14 days of gestation, respectively. These results indicated that diazepam treatment in pregnant rats caused considerable reduction of mean litter size, fetal body weight and fetal crown-rump length when treated during 5-9 days of gestation.

• Korean Journal of Veterinary Research
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• v.34 no.2
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• pp.219-227
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• 1994

The development of abomasum in fetuses between 60, 90, 120 days of gestation and neonates of Korean native goats was investigated by light, scanning and transmission electron microscopy. The results obtained were summarized as follows ; 1. The abomasum wall appeared to be differentiated into the epithelium, lamina propria, muscle layer, and serosa at 60 days of gestation. The epithelium was stratified columnar and these nuclei were located near the apical two thirds portion of the cell at 60 days of gestation, and then transformed into simple columnar epithelium with the flat basal nuclei. 2. The inner circular and outer longitudinal muscle layers were observed at 90 days of gestation and the blood vessels had become quite well developed as various arterioles, venules and capillaries of different size during this age. 3. Gastric pits were seen at 90 days of gestation and continued gradually to increase depth during gestation. 4. The mucous, parietal and chief cells appeared in epithelium at 90 days of gestation and continued gradually to increase in number during gestation. In 120 days fetuses and neonates, muscle layer had become very thickeness. 5. Scanning electron microscopically, the inner surface of the abomasum already consisted of wavy spiral folds which had many fine wrinkles at 60 days of gestation. In 90 day old fetuses, each spiral fold was enlarged and its surface was tended to be split into many straight longitudinal ridges and among these ridge were found shallow grooves, At 120 days, the subdivided swellings of ridges were progressively complicated in shape. In the neonates, the inner surface was flat and holed with many gastric pits. 6. Transmission electron microscopically, the epithelium was straified columnar and these nuclei were irregular shape at 60 days fetus. The parietal, chief and mucous cells were observed in 90 day old fetuses and continued gradually to increase in number during gestation. 7. The development of the abomasum was relatively slow at early stages, it was accelerated greatly in the last of gestation.

• Journal of Veterinary Clinics
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• v.18 no.2
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• pp.146-151
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• 2001

This study was carried out to find if the X-irradiation being used for clinical diagnosis during pregnancy would affect fetal development and cause fetal malformation in rats or not. To determine the dose and irradiation frequency of X-irradiation and gestation period by which fetal development would be affected when irradiated during pregnancy, seventy-two Sprague Dawley female rats (8 weeks old) were used for the experiment and grouped into three according to different gestation period of 5-8 days, and 6-12 days of gestation. Experimental rats were irradiated on the daily irradiation conditions of 40, 60, 80 kvp(kilo volt peak), 150 mA(milliampere), 0.25 sec and 4 times/day for both 5-8 days and 10-13 days of gestation, and 100 kvp, 100 mA, 2 min. and 4 times/day for 6-12 days of gestation. Rats were put in a small dark box when irradiated, which animals were sacrificed on the 20th day of gestation and mean litter size, fetal body weight, fetal crown-rump length(CRL) were investigated along with pathological findings. 1. Litter size were significantly decreased in the rats which were irradiated by both 60 and 80 kvp during 5 to 8 days of gestation and by 100 kvp during 6-12 days of gestation compared to those from the control rats(p<0.05) 2. Fetal body weight was significantly decreased in the fetus from the rats which were irradiated by both 60-80 kvp during 5-8 days of gestation and by 100 kvp during 6-12 days of gestation compared to those from the control rats(p<0.05). 3. There was no significant difference of fetal crown-rump length between all the experimental rats and the controls. 4. Fetal absorption, fetal death, and fetal malformation were not observed in the fetus form the rats irradiated by 40-80 kvp during 5-8 and 10-13 days of gestation, however, the pathological findings were found in those from the rats irradiated by 100 kvp during 6-12 days of gestation. 5. The harmful effect of x-irradiation on fetal development was estimated to occur when irradiated during 5-8 days of gestation. These results indicated that even X-irradiation for clinical diagnosis could affect fetal development in the early embryonic stage and when the fetus were exposed to frequent and prolonged x-irradiation with over dose.

• Korean Journal of Animal Reproduction
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• v.25 no.3
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• pp.231-235
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• 2001

Gestation duration of cow is an important economical trait. Shortening the gestation duration decreases the production cost and increases the competitiveness of Hanwoo industry. Thus, this study was carried out to analyse the effect of expected factors on gestation duration and make an alternative idea for reduced gestation duration. Gestation duration was not affected by cow-parity, but significantly affected by farm, Al year and sire. Therefore, reducing the gestation duration of Hanwoo may require both providing optimum feeding environment and nutrition management for cow and selecting optimum sire for AI.

• Journal of Embryo Transfer
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• v.14 no.3
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• pp.155-162
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• 1999

This study was carried out to establish an effective system for embryo transfer of techniques by analyzing several factors affecting the gestation length and the weight changes of calves produced from embryo transfer in Korean cattle. The results obtained in study on factors affecting the gestation length and the weight changes of calves produced from embryo transfer were as fallow; 1) The gestation length and the birth weight did not differ between male and female, but the weight changes after birth were remarkablely different between sex(P<0.05). 2) The gestation length between heifers and cows was not different, and body weights at birth and 6 months were remarkabley heavy in cows(P<0.05). Weight changes after 6 months were not different. 3) The gestation length and the birth weight were significantly different between the single and twin calving (P<0.05). Weight of twin at 6 and 12 months were remarkabely light. 4) Calving seasons did not affect the gestation length the and the birth weight. Weaning weight was significantly heavy(P<0.05), but weight changes after weaning were no different among the calving seasons. Conclusivley, this results suggest that cows will be better when considering growth of calves and twin produced from embryo trnsfer in Korean cattle.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.5
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• pp.640-647
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• 2008

Breed differences in adult animals are determined during fetal development. If interventions are to be developed that influence growth of muscle and fat, it is important to know at which time during gestation breed differences appear and are fixed. The objective of this study was to characterize fetal development in cattle of different breeds. Pregnant cows of 4 cattle breeds with different growth impetus and muscularity were slaughtered under normal processing conditions and the fetuses were removed. German Angus, a typical beef cattle; Galloway, a smaller, environmentally resistant beef type; Holstein Friesian, a dairy type; and Belgian Blue, an extreme type for muscle growth were used. Fetuses of each breed were investigated at 3, 6, and 9 mo of gestation. Fetuses were weighed and dissected into carcass, organs, and muscles. Body fat weight was obtained using the Soxhlet extraction method. Fetal weight increased most rapidly in the third trimester of gestation mainly due to the accelerated muscle and fat deposition. The organ weight to body weight (BW) ratios decreased and the muscle and fat weight to BW ratios increased. At 3 mo of gestation, Galloway fetuses had the significantly smallest BW, half-carcass weight, leg weight, organ weight, muscle weight and shortest leg length. In contrast, Holstein fetuses had the significantly greatest BW, liver, kidney, and lung weights and significantly longest leg length among the 4 breeds, but no differences between Holstein Friesian and Belgian Blue were detected in half-carcass and leg weight. Indeed, Belgian Blue fetuses had the significantly greatest half-carcass weight, leg weight, and muscle weight at 9 mo of gestation, and Galloway had a significantly greater body fat to BW ratio than Holstein Friesian and Belgian Blue. These differences were not evident at 3 and 6 mo of gestation. These data show that the profound increase of tissue and organ weights occurred in later gestation in cattle fetuses even though breed differences were evident as early as 3 mo of gestation. Depending on the tissue of interest, impacting fetal growth likely needs to occur early in gestation before the appearance of breed-specific differences.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.5
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• pp.722-731
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• 2020

Objective: Two experiments were conducted using 28 healthy multiparous sows to evaluate the oxidative stress status and reproductive performance of sows during gestation and lactation under different thermal environments. Methods: Fourteen multiparous sows were used in Exp. 1 under a high thermal environment, and the other 14 multiparous sows were used in Exp. 2 under a moderate thermal environment. In both experiments, reproductive performances of sows were recorded. Plasma samples were collected on d 35, 60, 90, and 109 of gestation, and d 1 and 18 of lactation for malondialdehyde, protein carbonyls, 8-hydroxy-deoxyguanosine, immunoglobulin g (IgG), and IgM analysis. Results: For sows in Exp. 1, plasma malondialdehyde concentration on d 109 of gestation tended to be greater (p<0.05) than it on d 18 of lactation. Plasma concentration of protein carbonyl on d 109 of gestation was the greatest (p<0.05) compared with all the other days. Plasma concentrations of 8-hydroxy-deoxyguanosine on d 109 of gestation was greater (p<0.05) than d 18 of lactation in Exp. 1. For sows in Exp. 2, there was no difference of malondialdehyde and protein carbonyl concentration during gestation and lactation. In both Exp. 1 and 2, litter size and litter weight were found to be negatively correlated with oxidative stress indicators. Conclusion: Sows under a high thermal environment had increased oxidative stress during late gestation indicating that increased oxidative damage to lipid, protein, and DNA could be one of the contributing factors for reduced reproductive performance of sows in this environment. This study indicates the importance of providing a moderate thermal environment to gestating and lactating sows to minimize the increase of oxidative stress during late gestation which can impair reproductive outcomes.

• Korean Journal of Veterinary Research
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• v.12 no.1
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• pp.7-14
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• 1972

Hemogram and serum composition of pregnant rabbits were studied and the results obtained were as follows: 1. Erythrocyte, hemoglobin concentration and hemotocrit value of pregnant rabbits decreased at the late stage of gestation, and 1 week after delivery the values were recovered to the normal levels. Number of erythrocyte and hematocrit value were not found to be significant, but hemoglobin concentration showed significant differences at the third and fourth week of pregnancy. 2. Total leucocytes of pregnant rabbits increased continuously as gestation progresses and 1 week postpartum the values were returned to normal. Highly significant changes were observed in the third and the fourth week of pregnancy. Neutrophil was revealed highly significant rise at the third and the fourth week of gestation and 1 week postpartum, but lympocyte was decreased highly significantlly. 3. Serum calcium of pregnant rabbits revealed the tendency of decrease as gestation progresses and 1 week after delivery the value was returned to normal, and highly significant decrease was abserved at the fourth week. Serum inorganic phosphorus of pregnant rabbits showed highly significant decrease at the fourth week of gestation, but no differences were observed at the other period of gestation and 1 week postpartum. 4. Serum protein of pregnants rabbits showed the tendency of decrease continuously pregnancy progresses, and 1 week after delivery showed the normal values. Highly significant decrease was found at the fourth week of gestation. the levels of serum lipids in pregnant rabbits was unchanged untill the third week of pregnancy, but at the fourth week and 1 week postpartum, the rise was highly significant. The level of total serum cholesterol in pregnants rabbis was shown the tendency of decrease untill the end of the second week of gestation and significantly dropped at the third week, thereafter, the value was rose significantly at the fourth week of gestation and 1 week postpartum.

• Korean Journal of Veterinary Research
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• v.35 no.1
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• pp.11-17
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• 1995

The development of colon in fetuses between 60, 90, 120 days of gestation and neonates of Korean native goats was investigated by light scanning electron microscopy. The results were summarized as follows : 1. The colonic wall appeared to be differentiated into the epithelium, lamina propria, submucosa, tunica muscularis and serosa in 60-day-old fetus. 2. The epithelium of the colonic villi was stratified in some areas and simple columnar in others at 60- and 90day-old fetus but was only observed simple columnar epithelium at 120-day-old fetus. 3. The goblet cells and the intestinal glands appeared in the colonic mucosa at 90 days of gestation and continued gradually to increase in number during gestation. 4. The well-developed villi of the colon appeared in columnar shape at 60 days of gestation and increased in length and width until 90 days of gestation but the villi appeared to be shorter and degenerated after 120 days of gestation. At birth only the rudiment trace of the villi remained. 5. The tunical muscularis of the colon was continuously developed during gestation period. The inner circular and outer longitudinal muscle layers were distinguishly observed in the colon of 90-day-old fetuses. 6. Scanning electron microscopically, the colonic villi developed in columnar shape or finger-like of fetuses at 60 days of gestation. The of the colonic villi became degenerated after 120 days of gestation. At birth only the rudiment trace of villi remained.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.9
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• pp.1328-1333
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• 2009

To evaluate different housing systems, 80 gilts were randomly allocated at puberty to four treatments: i) sow stall in gestation followed by farrowing crate (SC), ii) group housing with individual feeding in gestation followed by farrowing crate (GC), iii) ESF (Electronic Sow Feeding) system in gestation followed by farrowing crate (EC), and iv) ESF system followed by group farrowing pen (EG). The results showed that stalled sows had a longer interval between puberty and second estrus (p<0.001). The sows kept in the ESF system gained more body weight (p<0.01) and backfat (p<0.05) prior to service, and more backfat during gestation (p<0.05), but also had greater backfat losses in the subsequent lactation (p<0.01). Sows changing from loose housing to confinement at farrowing had longer gestation length (p<0.001). Total litter size did not differ significantly between gestation treatments, but the number of stillborn piglets was significantly higher in the SC treatment (p<0.01). After weaning, SC sows had the longest interval for rebreeding (p<0.001). Some EG sows came into heat before weaning, giving this treatment the shortest interval. These results indicate that gestation confinement in sow stalls had several detrimental effects on sow performance relative to group housing.