Studies on the artificial insemination in horses

Nishikawa, Y.; Waide, Y.

doi:10.2508/chikusan.20.123

Cited by 8 publications

(13 citation statements)

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“…Regarding gonadal development, the EP treatment promoted gonadal function in colts and fillies reared in Hidaka and fillies in Miyazaki. An increase in testicular hormone secretion was noted in colts, and promotion of follicular growth and advancement of ovulation were noted in fillies, clarifying that EP treatment promotes gonadal function in yearling fillies in a manner similar to broodmares [ 7 , 23 , 53 ]. No effect of the EP treatment on growth and gonadal function was noted in colts reared in Miyazaki, and the reason for this is unclear at this point.…”

Section: Discussionmentioning

confidence: 99%

Different effects of an extended photoperiod treatment on growth, gonadal function, and condition of hair coats in Thoroughbred yearlings reared under different climate conditions

Suzuki¹,

Mizukami

Nambo

et al. 2015

JES

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One- to two-year-old Thoroughbred colts and fillies being reared in Miyazaki (warm climate) and Hidaka (cold climate), Japan, were administered extended photoperiod (EP) treatment between December 20 and the following April 10, and its effect on growth, endocrine changes, gonadal activation, and hair coat condition was investigated. In colts reared in Miyazaki, no effect of EP treatment was noted on the growth indices, including body weight (BW), height at withers (HW), girth, and cannon circumference (CC), whereas the BWs and CCs of fillies were significantly higher in the EP treatment group than the control. In Hidaka, the BWs and HWs of colts and HWs of fillies were significantly higher in the EP treatment group. Gonadal activation characterized by an increase in circulating hormone concentrations was earlier in the EP treatment group for fillies reared in Miyazaki [luteinizing hormone (LH), follicle-stimulating hormone (FSH), progesterone (P4), and estradiol-17β (E2)] and in colts (LH, testosterone, and E2) and fillies (LH, FSH, P4, and E2) reared in Hidaka. Regardless of sex and climate, prolactin was significantly higher in the EP treatment group, whereas insulin-like growth factor (IGF-I) was not. Initial ovulation occurred before April in more of the EP treatment group than the control regardless of the climate. Molting of the hair coat, examined in March, was advanced in the EP treatment group regardless of sex and climate. These results suggest that EP treatment may promote growth and gonadal activation in fillies reared in Miyazaki and in colts and fillies reared in Hidaka and that the effect may be mediated by prolactin.

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Section: Discussionmentioning

confidence: 99%

Different effects of an extended photoperiod treatment on growth, gonadal function, and condition of hair coats in Thoroughbred yearlings reared under different climate conditions

Suzuki¹,

Mizukami

Nambo

et al. 2015

JES

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“…Utilizing the characteristic of horses that they are long-day seasonal breeders, EP treatment has been performed to advance ovulation in broodmares [ 10 , 16 , 37 , 40 , 43 ]. In the present study, the effect of EP treatment on the gonads and hair coat in Thoroughbred yearlings were investigated.…”

Section: Discussionmentioning

confidence: 99%

“…EP treatment advanced elevation of circulating prolactin in both colts and fillies. Previous papers reported that molting of winter hair coat was stimulated by long-day EP treatment [ 31 , 40 , 43 ], administration of prolactin [ 50 , 51 ] or sulpiride, antagonist of dopamine, [ 14 , 50 , 51 ] in horses. The present study clearly demonstrated that the early elevation of circulating prolactin observed in both colts and fillies was promoted by EP treatment.…”

Section: Discussionmentioning

confidence: 99%

“…Horses are typical long-day seasonal breeders. In the long-day period, circulating gonadotropins and gonadal hormones increase and testicular function is activated in stallions [ 12 , 13 , 37 , 38 , 43 ] and the ovarian function is activated and cyclic ovulation repeats in mares [ 13 , 33 , 36 , 39 , 43 ] making them fertile. A long-day period can be induced by lighting stalls, extending the lighting time during the short-day period.…”

mentioning

confidence: 99%

“…A long-day period can be induced by lighting stalls, extending the lighting time during the short-day period. Extended photoperiod (EP) treatment activates the ovarian function earlier in broodmares, and it is widely used to advance the ovulation time in broodmares in husbandry [ 43 ]. However, the effect of EP treatment on yearlings is unclear.…”

mentioning

confidence: 99%

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Effects of an extended photoperiod on gonadal function and condition of hair coats in Thoroughbred colts and fillies

Kunii

Nambo

Okano

et al. 2015

JES

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The effects of an extended photoperiod (EP) in Thoroughbreds colts and fillies from winter at one year old to spring at two years old on the gonadal functions, coat condition, and endocrine changes were investigated. Sixty-two Thoroughbreds (31 colts and 31 fillies) reared in the Hidaka Training and Research Center (Hidaka), Japan Racing Association were used. Thirty of them (15 colts and 15 fillies) were reared under EP conditions from December 20 to April 10, and the remaining 32 horses were reared under natural light alone as a control group. For EP, a 100-watt white bulb was set near the ceilings of stalls, and lighting conditions of 14.5-hr light and 9.5-hr dark periods were established. Blood was collected from the jugular vein once a month from October at one year old to February at two years old in both colts and fillies, and then twice a month in colts and weekly in fillies after March, and the coat condition was evaluated in January and April in 56 horses. To investigate endocrine changes, the plasma concentrations of prolactin, luteinizing hormone (LH), follicle-stimulating hormone (FSH), immunoreactive (ir-) inhibin, testosterone, estradiol-17β and progesterone were measured. No significant difference was noted in the coat condition between the two groups in January, but they changed from winter to summer coats (molting of winter coats) in April in the EP group compared with the control group. Regarding endocrine changes, the plasma concentrations of prolactin, FSH, ir-inhibin and testosterone were significantly higher in the EP colts than in the control group from January to April. The plasma concentrations of LH tended to rise in the EP colts from January to April compared with the control group. In the EP fillies, the plasma concentrations of prolactin, LH, ir-inhibin, estradiol-17β and progesterone were significantly higher during January and April, but a significantly high level of FSH was noted in the control than EP group in January. The ovulation day was advanced in the EP fillies compared with the control group. The present study clearly demonstrated that EP treatment during rearing advanced the molting of winter coats in both colts and fillies. These results suggested to be due to the action of prolactin being increased by EP treatment. In addition, EP treatment stimulated the hypothalamus-pituitary-gonadal axis even in yearlings, and advanced ovulation in fillies. Since EP treatment-induced changes in the yearlings were within the physiological range, and the method is safe and simple, EP treatment may be an effective technique in horse husbandry.

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Treatment with a High Dose Combination of PMSG/hCG Preparation of Mares Clinically Diagnosed with Ovarian Quiescence during the Breeding Season (Investigation from 1975 to 2000)

Tsukada¹,

Sato

Moriyoshi

et al. 2008

JES

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A total of 88 thoroughbred mares were diagnosed with clinical ovarian quiescence and subjected to four treatment regimens. Using PMSG, hCG or combinations of both. A high dose combination of 5,000IU PMSG with 5,000IU hCG showed significantly higher rates of marked estrus and ovulation induction (P<0.01) as well as conception rates (P<0.05). In the present study, the administration of a high-dose combination of PMSG with hCG was shown to be an effective treatment of ovarian quiescence in light mares.

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Studies on the artificial insemination in horses

Abstract: Studieson the artificial insemination in horses. III.A new preservation method of the horse spermatozoa, so-called Baken method Y. NISHIKAWA Y. WAIOE

Cited by 8 publications

References 0 publications

Different effects of an extended photoperiod treatment on growth, gonadal function, and condition of hair coats in Thoroughbred yearlings reared under different climate conditions

Different effects of an extended photoperiod treatment on growth, gonadal function, and condition of hair coats in Thoroughbred yearlings reared under different climate conditions

Effects of an extended photoperiod on gonadal function and condition of hair coats in Thoroughbred colts and fillies

Treatment with a High Dose Combination of PMSG/hCG Preparation of Mares Clinically Diagnosed with Ovarian Quiescence during the Breeding Season (Investigation from 1975 to 2000)

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