Equine reproductive physiology, breeding and stud management, 2008
This chapter describes the anatomy and function of the reproductive system of the stallion, inclu... more This chapter describes the anatomy and function of the reproductive system of the stallion, including the penis, accessory glands, vas deferens, epididymis, testes, spermatozoa, semen, ejaculation and spermatogenesis.
The objective of this study was to examine the influence of reactive oxygen species (ROS), genera... more The objective of this study was to examine the influence of reactive oxygen species (ROS), generated through the use of the xanthine (X)-xanthine oxidase (XO) system, on equine sperm motility, viability, acrosomal integrity, mitochondrial membrane potential, and membrane lipid peroxidation. Equine spermatozoa were separated from seminal plasma on a discontinuous Percoll gradient, and spermatozoa were incubated with 0.6 mM X and 0.05 U/mL XO for 30 minutes. Catalase (150 U/mL), superoxide dismutase (SOD, 150 U/mL), or glutathione (GSH, 1.5 mM) were evaluated for their ability to preserve sperm function in the presence of the induced oxidative stress. At the end of the 30-minute incubation, sperm motility was determined by computer-assisted semen analysis. Viability and acrosomal integrity were determined by Hoechst-Pisum sativum staining, and mitochondrial membrane potential was determined by staining with JC-1. Incubation with the X-XO system led to a significant (P < .01) increa...
Equine reproductive physiology, breeding and stud management, 2008
The choice of both mare and stallion for breeding can be a very complicated and time-consuming pr... more The choice of both mare and stallion for breeding can be a very complicated and time-consuming process. This chapter concentrates solely upon the criteria and techniques that can be used in the selection for reproductive competence and assumes that the selection criteria for performance and conformation have already been met. A wide range of techniques are included in the following sections, many of which are costly in time and money. The extent to which these techniques are used depends on personal choice and the value of the breeding stock concerned and potential offspring. It is suggested that if more attention is paid to assessment and selection of breeding stock on the basis of reproductive competence, significant amounts of money, time and effort would be saved in trying to breed from subfertile or infertile stock.
Jacks are bred to mares to produce mules. Traditionally, breeding management of jacks under domes... more Jacks are bred to mares to produce mules. Traditionally, breeding management of jacks under domestic conditions is considered challenging for both natural breeding and semen collection. The donkey&#39;s natural sexual behavior significantly differs from that of horses. This article describes the sexual behavior of donkeys and presents strategies to improve the breeding efficiency of jacks used for natural mating with
Despite the widespread use of hCG to advance ovulation in the mare there is little information on... more Despite the widespread use of hCG to advance ovulation in the mare there is little information on efficacy of dose rates and any contraindications of its use. This study aims to investigate the effect of dose of hCG on ovulation within 48h and the effect of hCG on: ovulation, multiple ovulation (MO), pregnancy, multiple pregnancy (MP) rates and synchrony of MO; additionally whether any seasonal effect is evident. Sequential ultrasonic scanning was used to monitor the occurrence of ovulation, within 48h of treatment, in 1291 Thoroughbred mares treated with either 750iu hCG or 1500iu hCG s.c. Ovulation rate, type (single ovulations (SO), MO, synchronous, asynchronous) and subsequent pregnancy were then monitored in 1239 Thoroughbred mares on a commercial stud over 3 years, 536 of which were treated with 750iu hCG at mating, all mares were also allocated into groups according to month of mating. No significant difference existed between the two dose levels of hCG and no significant difference existed between treated and untreated mares in overall ovulations (1.32 and 1.28 respectively), MO (31.7% and 27.7%), pregnancy (65.1% and 65.6%) or MP rates (10.8% and 11.8%). There was no significant association between month of year and pregnancy or MP rates for either treated or control mares, nor for MO for untreated mares. A significant (p&lt;0.05) association was evident between month and MO in treated mares, MO being lowest in April (22.3%). 95.9% of treated mares multiple ovulated within 48h compared with 90.7% controls, a near significant difference. In conclusion this study demonstrates that: (i) hCG dose of 750iu s.c. is just as effective in inducing ovulation within 48h as 1500iu, (ii) 750iu hCG has no significant effect on ovulation, MO, pregnancy or MP rates; (iii) a significant (p&lt;0.05) association exists between season and MO in hCG treated mares; (iv) a tighter synchrony (ovulation within 48h) of MO is evident in hCG treated compared with control mares (p=0.052).
Equine reproductive physiology, breeding and stud management, 2008
This chapter describes the anatomy and function of the reproductive system of the stallion, inclu... more This chapter describes the anatomy and function of the reproductive system of the stallion, including the penis, accessory glands, vas deferens, epididymis, testes, spermatozoa, semen, ejaculation and spermatogenesis.
The objective of this study was to examine the influence of reactive oxygen species (ROS), genera... more The objective of this study was to examine the influence of reactive oxygen species (ROS), generated through the use of the xanthine (X)-xanthine oxidase (XO) system, on equine sperm motility, viability, acrosomal integrity, mitochondrial membrane potential, and membrane lipid peroxidation. Equine spermatozoa were separated from seminal plasma on a discontinuous Percoll gradient, and spermatozoa were incubated with 0.6 mM X and 0.05 U/mL XO for 30 minutes. Catalase (150 U/mL), superoxide dismutase (SOD, 150 U/mL), or glutathione (GSH, 1.5 mM) were evaluated for their ability to preserve sperm function in the presence of the induced oxidative stress. At the end of the 30-minute incubation, sperm motility was determined by computer-assisted semen analysis. Viability and acrosomal integrity were determined by Hoechst-Pisum sativum staining, and mitochondrial membrane potential was determined by staining with JC-1. Incubation with the X-XO system led to a significant (P < .01) increa...
Equine reproductive physiology, breeding and stud management, 2008
The choice of both mare and stallion for breeding can be a very complicated and time-consuming pr... more The choice of both mare and stallion for breeding can be a very complicated and time-consuming process. This chapter concentrates solely upon the criteria and techniques that can be used in the selection for reproductive competence and assumes that the selection criteria for performance and conformation have already been met. A wide range of techniques are included in the following sections, many of which are costly in time and money. The extent to which these techniques are used depends on personal choice and the value of the breeding stock concerned and potential offspring. It is suggested that if more attention is paid to assessment and selection of breeding stock on the basis of reproductive competence, significant amounts of money, time and effort would be saved in trying to breed from subfertile or infertile stock.
Jacks are bred to mares to produce mules. Traditionally, breeding management of jacks under domes... more Jacks are bred to mares to produce mules. Traditionally, breeding management of jacks under domestic conditions is considered challenging for both natural breeding and semen collection. The donkey&#39;s natural sexual behavior significantly differs from that of horses. This article describes the sexual behavior of donkeys and presents strategies to improve the breeding efficiency of jacks used for natural mating with
Despite the widespread use of hCG to advance ovulation in the mare there is little information on... more Despite the widespread use of hCG to advance ovulation in the mare there is little information on efficacy of dose rates and any contraindications of its use. This study aims to investigate the effect of dose of hCG on ovulation within 48h and the effect of hCG on: ovulation, multiple ovulation (MO), pregnancy, multiple pregnancy (MP) rates and synchrony of MO; additionally whether any seasonal effect is evident. Sequential ultrasonic scanning was used to monitor the occurrence of ovulation, within 48h of treatment, in 1291 Thoroughbred mares treated with either 750iu hCG or 1500iu hCG s.c. Ovulation rate, type (single ovulations (SO), MO, synchronous, asynchronous) and subsequent pregnancy were then monitored in 1239 Thoroughbred mares on a commercial stud over 3 years, 536 of which were treated with 750iu hCG at mating, all mares were also allocated into groups according to month of mating. No significant difference existed between the two dose levels of hCG and no significant difference existed between treated and untreated mares in overall ovulations (1.32 and 1.28 respectively), MO (31.7% and 27.7%), pregnancy (65.1% and 65.6%) or MP rates (10.8% and 11.8%). There was no significant association between month of year and pregnancy or MP rates for either treated or control mares, nor for MO for untreated mares. A significant (p&lt;0.05) association was evident between month and MO in treated mares, MO being lowest in April (22.3%). 95.9% of treated mares multiple ovulated within 48h compared with 90.7% controls, a near significant difference. In conclusion this study demonstrates that: (i) hCG dose of 750iu s.c. is just as effective in inducing ovulation within 48h as 1500iu, (ii) 750iu hCG has no significant effect on ovulation, MO, pregnancy or MP rates; (iii) a significant (p&lt;0.05) association exists between season and MO in hCG treated mares; (iv) a tighter synchrony (ovulation within 48h) of MO is evident in hCG treated compared with control mares (p=0.052).
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