著者

Jeffrey A. FAWCETT Hideki INNAN Takeru TSUCHIYA Fumio SATO

出版者

Japanese Society of Equine Science

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.32, no.2, pp.31-37, 2021 (Released:2021-06-18)

参考文献数

18

被引用文献数

1

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Many studies have reported that advancing age in broodmares has a negative impact on the reproductive performance of horses. However, although the ages at first and last mating vary among broodmares, it is unknown how this variation affects the correlation between age and reproductive performance in mares. Here, in order to examine the effects of the ages at first and last mating, we analyzed all recorded mating events for Thoroughbreds in Japan from 1997 to 2017. We found that the live foal birth rate of mares with a younger age at first mating indeed declined at an earlier age than those with an older age at first mating and that the number of years since the first mating also contributes to the decline in the birth rate. We also found that the live foal birth rate and mean earnings of the produced foals are much higher for mares with an older age at last mating compared with mares with a younger age at last mating. Our results should aid breeders in assessing the value of broodmares and designing breeding strategies.

著者

Kaori M. Nakajima Manato Ohishi Fumio Sato Megumu Takahashi

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-045, (Released:2023-05-31)

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In Japan, broccoli (Brassica oleracea L. var. Italica) is primarily harvested manually. Some Japanese broccoli cultivars have short stems, but these broccoli heads are more difficult to harvest, and complicate the introduction of mechanical harvesters. Therefore, research is focused on strategies to control stem length. The present study examined the effects of the plant hormone gibberellin (GA) on the morphological and agronomic traits of broccoli shoots. The broccoli cultivar ‘SK9-099’, widely distributed in Japan and characterized by a short stem, was studied. These experiments were conducted over three cropping seasons, i.e., spring (Exp. 1), summer (Exp. 2), and fall (Exp. 3), with four GA treatment plots at 0 ppm (Control), 20 ppm, 100 ppm, and 500 ppm. This study observed that, on average, GA elongated stem length from approximately 16.0 cm in the control plot to 24.7 cm in the 500 ppm plot for the three cropping seasons, without decreasing yield. In addition, GA treatment accelerated apical bud growth and shortened the overall growth period by 16 days in the 500 ppm plot compared to the control in the fall, equivalent to 20.5% of the growth period from transplantation to harvest in the latter.This study highlights several practical benefits of GA application for growers, minimizing manual harvesting labor, avoid the difficult of designing mechanical harvesters for short-stemmed cultivars, and increase field usage efficiency by shortening the growth period.

著者

Pramod DHAKAL Akiko HIRAMA Yasuo NAMBO Takehiro HARADA Fumio SATO Kentaro NAGAOKA Gen WATANABE Kazuyoshi TAYA

出版者

The Society for Reproduction and Development

雑誌

Journal of Reproduction and Development (ISSN:09168818)

巻号頁・発行日

vol.58, no.5, pp.522-530, 2012 (Released:2012-11-01)

参考文献数

35

被引用文献数

21 16

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The present study was conducted to elucidate the profile of circulating gonadotropins and gonadal hormones from birth to puberty and relationship between gonadal seasonality and hormonal secretion in both sexes of Thoroughbred horses. Spring-born colts (n=6) and fillies (n=9) were blood sampled weekly from jugular vein from birth to 60 weeks of age. Circulating FSH, LH, prolactin, testosterone, progesterone, estradiol-17β, and immunoreactive (ir)-inhibin were measured by radioimmunoassay. In both sexes, the steroid hormones levels were remarkably high at birth, rapidly dropped within a week and remained at the lower levels until the start of second spring after birth. Ir-inhibin was also high during the birth, remaining lowest during winter and again increasing towards the second summer. There was an increase in FSH concentration in foals during the first summer months after birth and in the next summer, the FSH concentration along with that of LH increased significantly. The seasonal increase in circulating prolactin was remarkable even in the first year, and no differences were noted between the two summers. These results clearly demonstrated that the hypothalamo-pituitary axis is already responsive to changes in photoperiod and secrete prolactin similar to adult horses, but pituitary gonadotrophs for FSH and LH secretion is less sensitive. When the values of these hormones in the second breeding season after birth were compared with adult values of the respective sex in the breeding season, no significant differences were observed, indicating that spring-born fillies and colts have already attained the stage of puberty at the second breeding season after birth.

著者

Manato Ohishi Megumu Takahashi Machiko Fukuda Fumio Sato

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-022, (Released:2022-11-22)

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The demand for broccoli (Brassica oleracea L. var. italica) is increasing for use as fresh produce and for use in the processing industry. Therefore, growth prediction technology is required for its stable production. In this study, several cultivations of experiments were conducted to clarify the critical characteristics of the parameters needed to predict the growth of broccoli in a dry matter production model. The extinction coefficient was determined based on the leaf area index and intercepted solar radiation rate. Radiation-use efficiency was demonstrated using a linear function of the accumulated solar radiation intercepted amount and the total dry weight above-ground. The distribution of dry matter to the head and stem was indicated by the sigmoid function of the accumulated average temperature. The dry matter percentage of the leaf, dry matter percentage of the head and stem, and the ratio of leaf area to the fresh weight of the leaf were represented by a power function with dry weight above-ground. The fresh weight above-ground (R2 = 0.92) and the fresh weight of the head and stem (R2 = 0.98) were highly correlated with the estimated and observed values. Verification was performed using the developed growth model. As a result, the error between the harvest date and the predicted harvest date could be forecasted to within 4 days and the error in the fresh weight of the head could be predicted with an accuracy of −0.3 ~ +7.7 g·plant−1.

著者

Megumu Takahashi Takayoshi Ohara Fumio Sato Yuka Nakano Hidekazu Sasaki

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-018, (Released:2019-02-14)

被引用文献数

4

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Axillary buds of broccoli (Brassica oleracea L. var. Italica) develop and produce lateral heads after the apical heads have been harvested; however, lateral heads are not used because of their small size, and only one apical head is generally harvested from one plant. In this study, we aimed to establish a new method to harvest two heads of 12 cm diameter from a plant by pinching the apical bud and growing two axillary buds (“V-shaping” process) in autumn cropping. First, we measured the probability of axillary bud generation (PA) at each leaf axil and calculated the integration of the PA (IPA). The PA from the 5th to 8th true leaves was especially high, and the IPA reached 4.7. Next, we investigated the period of harvest and yield of heads at different times (3rd, 5th, 7th, 9th, 11th, 13th, and 15th leaf stage) of V-shaping in Field 1 (Ibaraki Prefecture, Tsukuba City). In V-shaped plots from the 7th to 11th leaf stages, the number of marketable heads significantly increased in comparison to that of the control. It increased by 61% of that of the control at the 11th leaf stage. However, the period of harvest was delayed, and the quality of heads deteriorated by cold injury when V-shaping was conducted from the 11th stage onward. Finally, we assessed the applicability of V-shaping cultivation in other fields. V-shaping was conducted from the 9th to 11th leaf stage. The number of marketable heads increased by 69 and 62% in Field 2 (Ibaraki Prefecture, Tsukubamirai City) and Field 3 (Nara Prefecture, Uda City), respectively. However, it only slightly increased in Field 4 (Mie Prefecture, Tsu City). Comparison of cultivation conditions at these 4 fields revealed that early transplantation, to allow an approximate 300°C day increase in effective heat unit summation for harvesting before the daily minimum temperature fell below approximately 0°C, was important. In addition, improving the drainage of the field seems important, and the input of manure compost (long-term fertilizer effect) may improve the quality and yield of heads. Thus, we concluded that V-shaping cultivation enabled the harvesting of two heads by V-shaping and increased the number of marketable heads by more than 60% in a wide area.

著者

Siriwan TANGYUENYONG Fumio SATO Yasuo NAMBO Harutaka MURASE Yoshiro ENDO Tomomi TANAKA Kentaro NAGAOKA Gen WATANABE

出版者

日本ウマ科学会

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.28, no.3, pp.77-86, 2017 (Released:2017-09-20)

参考文献数

43

被引用文献数

5

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This study aimed to compare body growth, metabolic, and reproductive hormonal changes in trained Thoroughbred yearling horses under different climate conditions with and without light supplementation (LS). Thoroughbred yearlings raised at research centers of the Japan Racing Association in Hokkaido (north) or Miyazaki (south) were divided into control and LS groups. In the LS groups, 44 colts and 47 fillies from Hokkaido and 11 colts and 11 fillies from Miyazaki were exposed to LS with an extended photoperiod of 14.5 hr of daylight and 9.5 hr of darkness. One week before and once a month after LS, circulating total thyroxine (T4), insulin-like growth factor-I (IGF-1), prolactin (PRL), cortisol, and progesterone (P4) concentrations were measured by radioimmunoassay and fluoroimmunoassay, respectively. Growth parameters, including body weight, height, girth, and cannon bone circumferences, were measured monthly. Hair coat (HC) condition was scored. Under natural conditions, the T4 concentrations of Hokkaido yearlings tended to be higher, whereas the IGF-1 (colt) and PRL levels were significantly lower than those of yearlings in Miyazaki. Growth parameters and HC scores were lower in Hokkaido yearlings. With LS, the PRL and P4 concentrations in Hokkaido and Miyazaki were higher, and the first ovarian activity tended to be earlier than in the controls. Only LS Hokkaido yearlings showed significantly higher HC scores than the controls. Comparing the different climates among the LS yearlings, the levels of PRL and P4 and the HC scores in Hokkaido yearlings increased and reached levels similar to those in Miyazaki yearlings. The body weight and girth increment percentages of Hokkaido yearlings in January dramatically decreased and then eventually increased to levels similar to those of Miyazaki yearlings. This suggested that yearlings in naturally colder Hokkaido exhibit higher basal metabolism to maintain homeostasis. However, providing LS may help to improve growth and early development of reproductive function in Hokkaido yearlings to levels equal to those of Miyazaki horses.

著者

Teruaki TOZAKI Fumio SATO Mutsuki ISHIMARU Mio KIKUCHI Hironaga KAKOI Kei-ichi HIROTA Shun-ichi NAGATA

出版者

日本ウマ科学会

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.27, no.3, pp.107-114, 2016 (Released:2016-09-30)

参考文献数

24

被引用文献数

1 11

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Ligand-dependent nuclear receptor compressor-like (LCORL) encodes a transcription factor, and its polymorphisms are associated with measures of skeletal frame size and adult height in several species. Recently, the single nucleotide polymorphism (SNP) BIEC2-808543 located upstream of LCORL was identified as a genetic diagnostic marker associated with withers height in Thoroughbreds. In this study, 322 Thoroughbreds-in-training were genotyped for BIEC2-808543 to evaluate the association between genotype and body composition traits, including body weight, withers height, the ratio of body weight to withers height, chest circumference, and cannon circumference. Of these, withers height and cannon circumference were significantly associated with LCORL genotypes throughout almost the entire training period in males and females. Animals with a C/T genotype had higher withers height (maximum differences of 1.8 cm and 2.1 cm in males and females, respectively) and cannon circumstance (maximum differences of 0.65 cm and 0.48 cm in males and females, respectively) compared with animals with a T/T genotype. These results suggested that the regulation of LCORL expression influences the skeletal frame size in Thoroughbreds and thus, indirectly affects the body weight. Although LCORL and BIEC2-808543 would be useful for selective breeding in Thoroughbreds, the production of genetically modified animals and gene doping based on genetic information should be prohibited in order to maintain racing integrity.

著者

Yoshiro ENDO Takeru TSUCHIYA Fumio SATO Harutaka MURASE Takaya OMURA Kenji KOROSUE Yasuo NAMBO Mutsuki ISHIMARU Yasuhiro WAKUI

出版者

公益社団法人 日本獣医学会

雑誌

Journal of Veterinary Medical Science (ISSN:09167250)

巻号頁・発行日

vol.74, no.8, pp.1079-1081, 2012 (Released:2012-09-03)

参考文献数

15

被引用文献数

5 11 3

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Prevalence of equine gastric ulcer syndrome in 85 young Thoroughbreds was investigated. The presence of gastric ulcers was confirmed in 27.1% (23/85) of the horses by endoscopic examination. Sixty-two horses without gastric ulcers were allocated randomly to either the treated group (31 horses) or sham-dosed control group (31 horses) in order to investigate the efficacy of omeprazole oral paste in the prevention of gastric ulcers. At the second endoscopic examination conducted after 28 days of administration, only 1 horse in the treated group developed gastric ulcers, while 12 horses developed gastric ulcers in the control group. Based on these data, the efficacy of omeprazole in prevention of equine gastric ulcers in young Thoroughbreds during the training period was confirmed.

著者

Kazutaka YAMADA Fumio SATO Tohru HIGUCHI Kaori NISHIHARA Mitsunori KAYANO Naoki SASAKI Yasuo NAMBO

出版者

日本ウマ科学会

雑誌

Journal of Equine Science (ISSN:13403516)

巻号頁・発行日

vol.26, no.3, pp.81-87, 2015 (Released:2015-09-30)

参考文献数

24

被引用文献数

1 6

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Bone mineral density (BMD) is one of the indications of the strength and health. BMD measured by quantitative computed tomography (QCT) was compared with that measured by dual energy X-ray absorptiometry (DXA) and radiographic bone aluminum equivalence (RBAE). Limbs were removed from horses that had been euthanized for reasons not associated with this study. Sixteen limbs (left and right metacarpals and metatarsals) from 4 horses were used to compare BMD as measured by QCT with those measured by DXA and RBAE. There was a strong correlation between BMD values measured by QCT and those measured by DXA (R2=0.85); correlation was also observed between values obtained by QCT and those obtained by RBAE (R2=0.61). To investigate changes in BMD with age, 37 right metacarpal bones, including 7 from horses euthanized because of fracture were examined by QCT. The BMD value of samples from horses dramatically increased until 2 years of age and then plateaued, a pattern similar to the growth curve. The BMD values of bone samples from horses euthanized because of fracture were within the population range, and samples of morbid fracture were not included. The relationship between BMD and age provides a reference for further quantitative studies of bone development and remodeling. Quantitative measurement of BMD using QCT may have great potential for the evaluation of bone biology for breeding and rearing management.

著者

Yoshiro ENDO Takeru TSUCHIYA Fumio SATO Harutaka MURASE Takaya OMURA Kenji KOROSUE Yasuo NAMBO Mutsuki ISHIMARU Yasuhiro WAKUI

出版者

JAPANESE SOCIETY OF VETERINARY SCIENCE

雑誌

Journal of Veterinary Medical Science (ISSN:09167250)

巻号頁・発行日

pp.1204080805, (Released:2012-04-13)

被引用文献数

7 11

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Prevalence of equine gastric ulcer syndrome in 85 young Thoroughbreds was investigated. The presence of gastric ulcers was confirmed in 27.1% (23/85) of the horses by endoscopic examination. For 62 horses without gastric ulcers were allocated randomly to either the treated group (31 horses) or sham-dosed control group (31 horses) in order to investigate the efficacy of omeprazole oral paste in the prevention of gastric ulcers. At the second endoscopic examination conducted after 28 days of administration, only 1 horse in the treated group developed gastric ulcers while 12 horses developed gastric ulcers in the control group. Based on this data, the efficacy of omeprazole in prevention of equine gastric ulcers in young Thoroughbreds during the training period was confirmed.

著者

Kenji KOROSUE Harutaka MURASE Fumio SATO Mutsuki ISHIMARU Takehiro HARADA Gen WATANABE Kazuyoshi TAYA Yasuo NAMBO

出版者

JAPANESE SOCIETY OF VETERINARY SCIENCE

雑誌

Journal of Veterinary Medical Science (ISSN:09167250)

巻号頁・発行日

pp.1203280800, (Released:2012-04-02)

被引用文献数

5 11

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The purpose of this study was to demonstrate that a barren parous Thoroughbred mare with lactation induced by hormonal treatment can be introduced to an orphan foal at the same farm and that the mare can become pregnant after the end of the hormonal treatment. An additional purpose was to investigate the changes in the plasma concentrations of prolactin, estradiol-17β, progesterone, follicle-stimulating hormone, and luteinizing hormone before, during, and after hormonal treatment. The difference in body weight between the adopted foal and the control foals, which were at the same farm and raised by their natural mothers, was 17 kg at 24 weeks old, when the foals were weaned. However, the adopted foal and the control foals had almost the same weight at 35 weeks old and later. The first ovulation after hormonal treatment was confirmed 10 days after the end of hormonal treatment and then the normal estrous cycle resumed. Furthermore, the changes in plasma progesterone, estradiol-17β, follicle-stimulating hormone, and luteinizing hormone showed regular patterns after the first ovulation. Conception was confirmed in the fifth ovulation. Meanwhile, another study demonstrated that conception was confirmed in the first ovulation after hormonal treatment. The present study is the first to demonstrate the hormonal profiles during and after induction of lactation in a Thoroughbred mare. This approach is useful for solving the economic and epidemic problems of introducing a nurse mare to an orphan foal.