Main Factors Affecting Mare Insemination With Cryopreserved Domestic and Foreign Sperm

Abstract

A b s t r a c tArtificial insemination (AI) has the following advantages over natural mating: fast selection effect, easy transportation, wide dissemination of valuable genetic material, economic use of semen and rational use of sires, preventing sexually transmitted infections, reserving sperm in cryobanks. Among the factors influencing the result of AI in horse breeding are time, frequency rate and insemination repetition, quality and quantity of semen, the depth of insertion of semen into the uterus of a mare, the observance of temperature mode and sanitary regulations during AI procedure, the reproductive performance of mares. There are two main approaches to freezing of stallion sperm and thus two AI technologies for semen packaging and equipment for its introduction into the uterus of mares. The first approach worked out and used in Russia is based on a sparing mode of semen cryopreservation in large volumes, 20-25 ml per dose. The second method, developed abroad, provides pre-treatment of sperm by centrifugation and maximum removal of semen plasma. In another procedure currently used in Russia the small volumes (5-6 ml) of semen are cryopreserved after centrifugation, removal of 50-60 % of semen plasma and thickening semen by dialysis. In recent years frozen semen of stallions from Europe and America is being actively imported to Russia. Despite the technological differences, domestic and foreign approaches to the cryopreservation of stallion's semen provide its similar qualitative characteristics after thawing. The aim of our research was to identify the most significant factors affecting pregnancy rates in artificially inseminated mares when domestic and foreign protocols were used to freeze sperm. Herein, an impact of five such factors (i.e. sperm packing/cryopreservation technology, time of insemination, reproductive state and gynecological soundness of the mares, the activity of sperm) on the effectiveness of AI with frozen semen was estimated in mares of various breeds (Arabian, Akhal-Teke, Trakehner, Hanoverian, Russian Riding horse, American Standardbred, Russian Trotter and Orlov Trotter). Experiments were carried out in 2012 to 2014 at Tersk stud, at a private farm (Mr. A.A. Kazakov the owner) and at experimental stable of the All-Russian Research Institute for Horse Breeding. We compared the data on 106 estrus cycles of 53 mares, artificially inseminated with domestic (granules and tubes of 5 ml and 15-25 ml) and foreign frozen semen (0.5 ml in straws). All used sperm doses in various packages were divided into two groups with the activity above and below 1.5 points (15 %). The time recommended for AI with frozen semen was divided into three intervals (12 h before ovulation, during ovulation, 6 h after ovulation). The animals were conventionally grouped as barren and maiden mares, lactating mares, mares after late (6 or more months of pregnancy) abortion, and also with regard to absence or presence of gynecological pathologies such as vaginal discharge, fluid and air in the uterus, mating-induc...

Reproductive Characteristics of Thawed Stallion Sperm

“…One ejaculate of each stallion was used in all sperm and artificial insemination studies of the mares. AIs were performed by transcervical injection of the dose of either fresh or thawed sperm with preliminary control of follicle development 1-4 h before and after ovulation [8]. In all, 252 mares were artificially inseminated in one sex cycle.…”

Conservation of Genetic Resources in Horse Breeding and Major Structural Damages of Sperm During Semen Cryopreservation in Stallions

“…In 1954 the Institute for Horse Breeding received the world's first foal from the artificial insemination by cryopreserved sperm. The collection of genetic resources of ARRIH has been successfully working since 1972 and nowadays contains cryopreserved sperm from 56 stallions of 16 breeds of domestic and foreign selections (Lebedeva et al, 2015). Scientists store cryopreserved sperm of many stallions in a biocollection for several decades and use it for artificial insemination of mares.…”