• Korean Journal of Veterinary Research
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• v.44 no.2
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• pp.293-301
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• 2004

We investigated the effect of reproductive herd health program (RHHP) on the reproductive performance in high yielding dairy herds. Data collected from 205 lactations at Boeun County, Chungbuk from April 2001 to Dec. 2003 included postpartum reproductive and metabolic diseases, body condition score (BCS), reproductive performance and milking records. First we compared the reproductive performance of cows without RHHP (pre-RHHP group) and cows with RHHP (RHHP group). Intervals from calving to first service (99.6 vs. 81.8 days) and to conception (160.3 vs. 131.8 days) were shorter in the RHHP group than in the pre-RHHP group. Secondly, we determined the effect of milk yield (305 days) on the occurrence of postpartum diseases, BCS changes, and reproductive performance in cows under RHHP. The occurrence of metritis and metabolic diseases were greater in the over-10,000 kg group than in the under-10,000 kg group. The over-10,000 kg group lost more body condition than the under-10,000 kg group from calving to month 3 postpartum. Nevertheless, reproductive performance did not differ between the two groups. These results indicate that reproductive performance can be improved by the application of RHHP in high yielding dairy herds and that reproductive performance in the cows under RHHP are not affected by high milk yielding.

• Animal Bioscience
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• v.36 no.11
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• pp.1619-1631
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• 2023

The objective of this review was to provide an overview of the effects of dietary fiber (DF) on reproductive performance in gestating sows. Dietary fibers have been suggested to modulate microbiota in the intestine and the immune system of gestating sows and to improve gut health. Thus, DF may help alleviate the adverse effects of the stressful production cycle of gestating sows. These benefits may subsequently result in improved reproductive performance of sows. Previous studies have reported changes in microbiota by providing gestating sows with DF, and the responses of microbiota varied depending on the source of DF. The responses by providing DF to gestating sows were inconsistent for antioxidative capacity, hormonal response, and inflammatory response among the studies. The effects of DF on reproductive performance were also inconsistent among the previous studies. Potential reasons contributing to these inconsistent results would include variability in reproductive performance data, insufficient replication, influence of other nutrients contained in the DF diets, characteristics of DF, and experimental periods. The present meta-analysis suggests that increasing the total DF concentration by 10 percentage units (e.g., 12% to 22% as-fed basis) in gestating sow diets compared to the control group improves the litter born alive by 0.49 pigs per litter. However, based on the present review, questions remain regarding the benefits of fibers in gestating sow diets. Further research is warranted to clarify the mode of action of fibers and the association with subsequent reproductive performance in gestating sows.

• Korean Journal of Animal Reproduction
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• v.23 no.4
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• pp.371-380
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• 1999

Animal reproductive performance could be affected by several regulatory factors, including nutritional, environmental, and genetic factors. Particularly, during the last half of this century, animal reproductive performance has been remarkably successful in improving the efficiency of livestock production. For some traits efficiency gains have been achieved with little or no knowledge of the genes underlying the traits. And, they have depended upon the phenotypic selection by statistical methods to estimate the genetic parameters of some reproductive traits. In spite of these successes, it is clear that recent advances in both developmental biology and molecular biology are set to revolutionize he practice of animal reproductive performance n the 21th century. (omitted)

• Journal of Embryo Transfer
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• v.24 no.2
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• pp.127-130
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• 2009

The purpose of this study was to determine the effect of cows parity and calving seasons on the subsequent reproductive performance of the herd of Korean native cows raised under the same condition. With the parity of the cows ranged 1 to 4 (mean: 1.9), significant associations were found between parity and calving interval (p<0.05). Calving interval of the primiparous cows group was 395.0 ${\pm}$ 16.5 days, which was the longest calving interval among the four groups. On the other hand, calving interval of the second parity group was 333.7 ${\pm}$ 3.6 days. The primiparous cows had tendencies that long interval from calving to conception and small number of service per conception relatively when compared with the multiparous cows. In the case of calving season, the interval from calving to first service was short in summer and winter relatively. The interval from calving to conception in summer was the shortest in four seasons. The number of service per conception was larger in spring and winter and smaller in summer and autumn. Calving in spring showed delayed reproductive performance and calving in summer showed desirable reproductive performance.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.956-965
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• 1999

Genetic selection and sophisticated management technology have produced modern sows which excel in litter size and milk production. Recent research has identified nutritional innovations which may enhance productivity of the high producing sow. Selected research in three areas which have the potential to enhance reproductive performance are summarized in this report. First, preliminary evidence indicates that organic chromium may enhance litter size and conception rate. Secondly, high producing sows, particularly primiparous sows, required higher protein/lysine in late gestation and or lactation to optimize weaning weight and subsequent litter size. Valine and isoleucine, but not leucine, have been shown to enhance milk production. Phased feeding programs with diet cost partitioned toward gilts and away form parity 3 to 8 sows have been suggested as a means of improving reproductive performance in young sows. Lastly, recent research with sufficient sow numbers to document the effect of dietary fiber on reproductive performance has shown that sows fed fiber farrowed and weaned more pigs.

• Korean Journal of Veterinary Research
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• v.62 no.2
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• pp.15.1-15.8
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• 2022

The objective of this study was to identify risk factors for repeat breeder dairy cows and their impact on reproductive performance. The characteristics of 1,504 cows, including their peripartum health, nutrition, production, and reproduction, were collected. Cows with metabolic disorder were significantly more likely (odds ratio [OR], 2.47; p < 0.001) and cows with clinical endometritis tended to be more likely (OR, 1.35; p < 0.1) to become repeat breeders than cows without metabolic disorder and clinical endometritis, respectively. Cows initially inseminated > 80 days after calving were less likely (OR, 0.78; p < 0.05) to become repeat breeders than cows initially inseminated ≤ 80 days after calving. As a result, repeat breeding in dairy cows resulted in a 90 day longer (p < 0.0001) mean interval from calving to pregnancy. In conclusion, postpartum metabolic disorder, clinical endometritis, and a short interval from calving to initial insemination were risk factors for repeat breeder dairy cows, resulting in a severely impaired reproductive performance.

• Korean Journal of Animal Reproduction
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• v.16 no.3
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• pp.261-267
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• 1992

The reproductive performance of SPF ICR mice under single paired mating were examined to get reproductive background data and to establish single paired rotational mating system. The results obtained were as follows : average litter size was 15.4$\pm$2.0 heads ; average weaning rate was 95.7$\pm$4.9% ; sex ratio(male/female) was 1.09$\pm$0.26 ; aveage delivery interval was 23.0$\pm$2.4 days. It was given the largest litter size at the age of 121~150 days and in 2nd~4th parities, but at the age of under 90 days and in 1st parity weaning rate and delivery interval were higher and shorter than those of the other ages and parities, respectively. In sex ratio, the number of male litters was slightly increased from that of female litters. The weaning rate of litters from dams which nuresed 12 litters was the highest among those of different litter sizes, and it was decreased dependent upon increment of litter size. There were no difference among 4 groups for reproductive performance, therefore the present study could have important sources for animal breeders who produce mice using the single paired rotational mating system.

• Journal of Embryo Transfer
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• v.30 no.3
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• pp.189-193
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• 2015

Calculating break-even price of calf production is closely associated with reproductive efficiency. To determine the price, we need data from reproduction records including number of claves weaned, number of cows exposed for breeding, and annual cash coast per cow, and average weaning or market weight of claves sold and retained. Unfortunately, the data were not available in Korea native cow (Hanwoo). To evaluate the performance and the price, we collected calving interval from about 60,000 cows for last 10 years and estimated reproductive performance. Calving interval was increased 4.3% and pregnancy rate was decreased about 1.4~2.8% year-on-year. Increases in growth rates of number of cow and semen per calf supported the low reproductive performance. Finally, break-even price was calculated using estimated percent calf crop and demonstrated that growth rate of break-even price is larger than that of annual cash per cow, suggesting cow-calf profitability and financial efficiency in Korea native cow (Hanwoo) is getting worse.

• International Journal of Industrial Entomology and Biomaterials
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• v.29 no.1
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• pp.128-134
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• 2014

Nesolynx thymus Girault (Hymenoptera: Eulophidae) is one among 20 hymenopteran parasitoids reported to attack the uzi fly, Exorista bombycis, which in turn infests the silkworm, Bombyx mori accounting a cocoon yield loss of 10-20%. A host of factors viz., age and size of host, age and size of parasitoid, availability of host, temperature and quality of host are reported to influence the reproductive efficiency of the parasitoids. In the present study an attempt was made to record the influence of foraging parasitoid density on their reproductive performance. Three day-old uzi pupae were offered to varying numbers (1 - 10) of 2 day old Nesolynx thymus adults for parasitization. The progeny production per pupa (84.44 - 132.77) increased significantly with increase in the number of foraging parasitoid adults (1 - 10) however, progeny production per female decreased. The sex ratio (M : F) (1:25.49 - 1:1.53) decreased significantly with increase in foraging parasitoid adults. The morphometric parameters except female abdomen width of first generation parasitoid showed significant negative correlation with number of foraging adults. However, correlation between the parasitoid size in first generation and their reproductive performance was nonsignificant.

• Journal of Embryo Transfer
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• v.30 no.1
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• pp.59-64
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• 2015

Intensive genetic selection has resulted in modern dairy cow with very high milk yields but reduced fertility, due mainly to an increase in reproductive disorders. The study was conducted to estimate the proportion of reproductive disorders among dairy cattle. The factors analyzed were; milk yield, cow parity, periparturient disorders, and reproductive status. The result of this study showed the incidence of reproductive disorders in high yielding dairy cows was prevalent. Repeat breeding was the major postpartum reproductive problem comprising (42.3%) of the samples. Higher reproductive disorders were also associated with lower parity. These disorders subsequently reduced reproductive performance by prolonged intervals from calving to first artificial insemination and from calving to pregnancy. Abnormalities in the reproductive system such as repeat breeder, silent heat, anestrous and ovarian cysts, as well as lower fertility have been recorded during the summer months (June to August). In conclusion, the study revealed that incidence of repeat breeder is mostly prevalent in dairy cows. Moreover, the incidence of reproductive disorders was higher in summer season and hence appropriate preventive and or therapeutic measures as per the type of abnormalities need to be undertaken.