Genetics in horses encompasses the study of hereditary traits and the genetic makeup that influences various characteristics and health conditions in equine populations. This field involves the analysis of genes and their functions, inheritance patterns, and the impact of genetic variations on traits such as coat color, performance ability, and susceptibility to diseases. Research in equine genetics employs techniques such as genome mapping, sequencing, and genetic testing to identify specific genes and mutations associated with these traits. This page gathers peer-reviewed research studies and scholarly articles that explore the genetic basis of equine traits, the methodologies used in genetic research, and the implications for breeding, health management, and conservation of horse breeds.
Bornstein S.Two intersex horses were characterized externally by vulva and “enlarged clitoris-hypoplastic penis” and internally by uterus and testicles. Both had a normal female karyotype 64/XX. One of the horses whose body measurements were in accordance with mares of the same breed, showed a distinct stallion behaviour.
Irfan M.Studies have been made on the effect of storage and temperature on factor V in animals and a method for its assay is described. There was a decrease of the factor with age in oxalated plasma of cattle, horses, sheep, dogs, rabbits and one elephant. This deterioration was very rapid in plasma kept at 37C. as compared with that stored at 4C. Rabbit plasma had the highest concentration of factor V followed by dogs, horses, cattle and sheep. Mixing various dilutions of aged plasma kept at 4C. wlth fresh plasma would enable the percentage prothrombin activity to be determined for the assay of facto...
Loy RG, Swan SM.Progesterone in oil solution injected into mares intramuscularly in midcycle blocked estrus and ovulation at levels of 100 mg. per day or higher. Fifty milligrams per day prevented estrus but not ovulation. The interval from end of treatment to estrus appeared to depend upon dosage, and the effects on subsequent cyclic patterns were confounded by season of the year. Neither 50 nor 100 mg. per day stopped estrus or blocked ovulation when treatment was started on day 1 of estrus. Injection of 100 mg. per day of progesterone in oil delayed postpartum estrus and ovulation, but 50 mg. per day did n...
Guèrand M, Mahla R, Lagneaux D, Amigues Y, Palmer E, Bézard J.Paternity analysis was performed on the DNA of 21 equine embryos collected nonsurgically 10 days after ovulation from known mares, but involving 3 possible sires. After extraction, the DNA of each embryo was typed by radioactive PCR amplification using 10 characterised microsatellites; HMS 1, 2, 5, 6, 7 and 8 (Guérin et al. 1994) and HTG 3, 4, 6 and 10 (Marklund et al. 1994). The 21 dams and 3 sires were genotyped using DNA extracted from blood and amplified by PCR. After electrophoresis and autoradiography of the PCR products of the embryo and parents, the alleles of the embryo were compared...
Huhtinen M, Peippo J, Bredbacka P.Embryo biopsy has been used to detect inherited disorders and to improve the phenotype by analyzing of linkages between marker loci and the desired characteristics. Unfortunately, early procedures required the removal of a large portion (one-half) of the embryo for analysis, and the transfer of bisected equine embryos has not been particularly successful. Recent discovery of the polymerase chain reaction (PCR) has made possible the detection of specific DNA sequences from only a few cells. We investigated whether the removal of a small biopsy would allow for successful PCR and normal embryonic...
Evenson DP, Jost LK, Varner DD.Data from the sperm chromatin structure assay (SCSA), a flow cytometric measurement of susceptibility of sperm nuclear DNA to denaturation, show strong correlation with the fertility potential of bulls, boars, men and stallions. Previous studies showed a strong relationship between stallion spermatozoa with denatured DNA and the presence of DNA strand breaks. In the present study, the relationship between stallion sperm DNA denaturation and the redox status of -SH groups on the cysteine residues of sperm nuclear protamines that are thought to stabilize chromatin was investigated. Semen samples...
Bouchard PR, Fortna CH, Rowland PH, Lewis RM.Granular cell tumor (GCT) is a morphologic designation for tumors of varied histogenesis. Most GCTs in human beings are derived from Schwann cells, and rat meningeal GCTs are believed to originate in the neural crest. Three equine pulmonary GCTs from aged horses were studied immunohistochemically with primary antibodies directed against vimentin, cytokeratins (AE1/AE3), S-100, Leu 7, desmin, and neuron-specific enolase (NSE) using a steptavidin-biotin procedure. All three tumors stained similarly with strong and diffuse staining of neoplastic cells for vimentin and S-100 and negative staining ...
Mobarak MS, Ryan MF.Light, scanning, and transmission electron microscopy were employed to provide further data on the putative origins of the immunogenic secretory-excretory product (ESP) of Strongylus vulgaris (Looss 1900). The sharply delineated but superficial attachment to the equine caecum by the mouth leaves behind an oval area devoid of epithelial cells. Attachment does not extend deeply enough to reach the muscularis mucosa layer of the equine intestine. The progressive digestion of the ingested plug of tissue (epithelial cells, blood cells and mucous) was visualized. The coelomocytes, floating cells and...
Cheng HW, Chik TK, Weir J, Chan BP.Damage to the hyaline cartilage of the joint surface and osteochondral fractures are key factors leading to the development of osteoarthritis in racehorses, representing a significant cause of racehorse retirement. To tissue-engineer an osteochondral unit that is suitable for joint repair, incorporation of a zone of calcified cartilage should be considered so as to mimic itscounterpart. To date, equine mesenchymal stem cells (eMSCs) have been reported to have multilineage differentiation potential. Yet the generation of a zone of calcified cartilage using eMSCs has not been reported. This work...
Liang CZ, Cao RB, Wei JC, Zhu LH, Chen PY.According to the antigenic analysis of equine arteritis virus (EAV) GL protein, one pair of primers were designed, with which the gene fragment coding the high antigenic domain of EAV GL protein was amplified from the EAV genome. The cloned gene was digested with BamH I and Xho I and then inserted into pET-32a and resulted pET-GL1. The pET-GL1 was transformed into the host cell BL21(DE3) and the expression was optimized including cultivation temperature and concentration of IPTG. The aim protein was highly expressed and the obtained recombinant protein manifested well reactiongenicity as was c...
McDowell KJ, Adams MH, Williams NM.Proteins synthesized and released in vitro by oviducts collected from horse mares during estrus and at day 4 after ovulation for bred and nonbred mares were examined by two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (2-D SDS PAGE) and fluorography. Ampullary and isthmic regions both produced a wide array of nondialyzable proteins in culture. Major proteins or groups of proteins identified according to relative molecular weight (kDa) and apparent isoelectric point (pI) were at 100 kDa, pI 8; 100-200 kDa, pI 6; 150 kDa, pI 4.5; 60-100 kDa, pI 4; and an array of polypep...
Bai Y, Tong T, Liu G, Chen W, Zhang W, Wang Q, Yang T, Bu Z, Wu D.Interferon gamma (IFN-gamma) is a pleiotropic cytokine that is recognized as an important modulator of the immune response. To date, there is no report that prokaryocyte-derived recombinant equine IFN-gamma has antiviral activity. In this report, the gene coding equine IFN-gamma (EIFN-gamma) mature protein was cloned into pET-28a (+) and the recombinant EIFN-gamma was expressed in Escherichia coli (E. coli). The antiviral activity of expressed recombinant EIFN-gamma was evaluated by using a recombinant Vesicular Stomatitis Virus expressing green fluorescence protein (rVSV-GFP) system in the eq...
Asin J, Murphy BG, Samol MA, Polanco J, Moore JD, Uzal FA.Rickets is a metabolic bone disease associated with failure of endochondral ossification and impaired osteoid mineralization in growing animals. As a consequence, affected individuals can develop gross and microscopic bone malformations. The most common causes of rickets in domestic species include vitamin D and phosphorus deficiency. Rickets has been described in multiple species; however, comprehensive postmortem characterizations with confirmatory histopathology in equids have not been published. A 6-mo-old, Thoroughbred-cross foal was diagnosed with rickets based on gross autopsy findings ...
Kramer KJ, Kagan IA, Lawrence LM, Goff BM, Smith SR.An excess of water-soluble carbohydrates (WSCs) can present a risk for horses prone to pasture-associated laminitis or some other metabolic conditions. Determining WSC concentrations in commonly grazed cool-season grasses, at different times of day and under different fertilization treatments, can help optimize grazing times and management strategies. The goals of this study were to develop a near-infrared reflectance spectroscopy (NIRS) calibration curve for WSC and to apply it to four cool-season grass species. Tall fescue, Kentucky bluegrass, orchardgrass, and perennial ryegrass (10 cultiva...
Ohya T, Kondo T, Yoshikawa Y, Watanabe K, Orino K.In mammal circulation, various ferritin-binding proteins (FBPs) are thought to be involved in the clearance of circulating ferritin after complex formation with it. However, horse FBPs are known to cause inhibitory effects on ferritin immunoassay due to the concealment of the ferritin molecule to anti-ferritin antibodies used in the ferritin immunoassay. These inhibitory effects are eliminated by heat treatment of horse serum at 75°C for 15 min. The inhibitory effects on ferritin immunoassay in the sera of ten foal sera (5 females and 5 males) from 1 to 18 months were detected during all peri...
Tesfaigzi Y.Exposure of airways to environmental toxins or allergens induces proliferation of epithelial cells. Depending on the type of exposure, existing and newly formed cells can differentiate into mucus-producing cells resulting in mucous cell metaplasia (MCM). During recovery, the epithelium reduces the number of epithelial cells to return to the original state. Understanding the mechanisms involved in this resolution could be useful in deleting mucous cells and, thereby, mucous secretions. We have found that metaplastic mucous cells induced by exposure to ozone, endotoxin, cigarette smoke or allerg...
Niwa H, Anzai T, Hobo S.Contagious equine metritis (CEM) is a highly contagious bacterial venereal disease of horses caused by Taylorella equigenitalis. CEM-PCR is a semi-nested PCR method for detecting this bacterium. Although this technique is regarded as a sensitive diagnostic method for CEM, there are risks of it generating false positive and false negative results. In this study, we constructed a recombinant plasmid (CEM-POS) as reaction control to assure adequate PCR reaction and prevent false positive results caused by contamination of the reaction control in routine CEM-PCR examinations. CEM-POS was construct...
Aureli G, Lauria A.The results of a study on interstitial cells of the horse gonads from foetal life to puberty are reported. The morphological (also ultrastructural) histochemical, histophysical and histoenzymological findings both in the organ and in monolayer cultures, clarify the problem of the ontogenesis of these cells showing that: --foetal interstitial cells give origin to "xanthochrome" cells; --"xanthochrome" cells in the prepuberal gonad are continuously renewed; --the same type of cells which in th prepuberal period undergo lipochromic degeneration, differentiate at puberty into Leydig cells in the t...
Westermann CM, Parlevliet JM, Meertens NM, Sloet van Oldruitenborgh-Oosterbaan MM.Mares regularly have an enlarged ovary. The main causes are haematomas, anovulatory follicles, abscesses, and neoplasia. The granulosa-theca-cell tumour is by far the most common neoplasia of the ovary (about 97%) and accounts for 2.5% of all equine tumours. In this article the differential diagnosis of an enlarged ovary and the background of granulosa-theca cell tumours are reviewed. A case is described of a mare with a very large granulosa-theca cell tumour in the left ovary, which was discovered 1 month after delivery of a healthy foal. This case is special not only because the tumour was e...
Brück I, Lehn-Jensen H, Yde G.A Warmblood mare was observed to ovulate spontaneously 12 follicles within 2 days, none of which exceeded 22 mm in diameter. On Days 13 and 17 after ovulation, 6 embryonic vesicles were identified in the uterus by ultrasonography but by Day 26, 5 of the vesicles had disappeared. Development of the surviving conceptus was monitored until Day 42. Plasma progesterone concentrations rose to 14 ng/ml on Day 7, decreased over the next 8 days and then plateaued to around 4-6 ng/ml until Day 70. The occurrence of multiple spontaneous ovulations was diagnosed repeatedly in this mare. However, the devel...
van Grevenhof EM, Gezelle Meerburg ARD, van Dierendonck MC, van den Belt AJM, van Schaik B, Meeus P, Back W.Osteochondrosis (OC) is a common, clinically important joint disorder in which endochondral ossification is focally disturbed. Reduced blood supply to growing cartilage is considered an important cause of the condition, which has both genetic and environmental origins. Housing conditions can influence cartilage injury through peak-pressure changes during limb sliding. Additionally, circulatory perturbation can cause the avascular necrosis of cartilage. In this study, we evaluated the type and frequency of limb sliding during standing up and the occurrence of OC in foals aged up to 12 months o...
Morris LH.The generally recommended minimum number of spermatozoa required for conventional artificial insemination in the mare is in excess of 200 x 10(6) progressively motile spermatozoa. Recent developments in different insemination techniques such as deep uterine, hysteroscopic and oviductal insemination, which have been designed to use significantly fewer spermatozoa, are reviewed in this paper. A number of studies have demonstrated that ultrasound guided deep uterine insemination of 5 x 10(6) fresh spermatozoa can produce satisfactory pregnancy rates. The use of hysteroscopic insemination enables ...
Magnuson NS, Decker DM, Perryman LE.The effect of adenosine, deoxyadenosine, guanosine, and deoxyguanosine on the growth rate of fibroblasts derived from normal horses, horses heterozygous for the severe combined immunodeficiency (SCID) trait (heterozygotes), and horses with SCID was studied. All four purines were found to inhibit growth in a dose-dependent manner, but only adenosine and deoxyadenosine were inhibitory at concentrations of less than 100 microM. No statistical difference in sensitivity to adenosine was detected between normal and SCID fibroblasts. Fibroblasts from SCID horses were, however, more sensitive to the g...
Blue MG.This study provides accumulated data to assist the definition of karyotypes from normal and infertile horses. The normal karyotype of the horse (2n = 64) was characterized following Giemsa staining and C- banding, and 23% aneuploidy was found among chromosome counts of cells prepared from 44 clinically normal horses and 24 equine embryos. These expected variations in chromosome counts are especially important in the evaluation of potential mosaicism. Centromere staining was shown to be a valuable aid for the identification of specific chromosomes, in particular the sex chromosomes. Sex chromat...
Clément F, Vincent P, Mahla R, Meriaux JC, Palmer E.The aim of the present study was to determine which artificial insemination results in fertilization when mares are inseminated several times before ovulation. Mares in oestrus were inseminated over 62 cycles with fresh semen at 48 h intervals from when a follicle > or =30 mm in diameter was detected until ovulation. The number of inseminations was limited to three. Three fertile stallions were used and a different stallion was used for each artificial insemination. The order of the three stallions was changed for each cycle. Embryos were collected between day 10 and day 12 after ovulation and...
Black WD, Hartley CA, Ficorilli NP, Studdert MJ.Equine rhinitis B virus (ERBV), genus Erbovirus, is most closely related to the Cardiovirus genus in the family Picornaviridae. The structural proteins (VP1-4) of erboviruses are not well described, but are predicted by sequence to be 35, 29, 26 and 7 kDa. Methods for the purification of cardioviruses (polyethylene glycol, trypsin treatment) were used to characterise the structural proteins of ERBV1. Only one of the virus proteins detected was an expected molecular mass, and this 26 kDa protein was identified as VP3 by N-terminal amino acid sequencing. N-terminal sequencing of the 56 and a 29 ...
Broström H, Troye-Bomberg M, Perlmann P.To analyze in vitro lymphocyte-mediated immune responses of horses with sarcoids against allogeneic sarcoid cells containing endogenous retrovirus but not expressing major histocompatibility complex antigens. Methods: Lymphocyte-mediated immune reactions were assessed by means of proliferative responses in mixed lymphocyte tumor cell culture (MLTC) assay and lymphocyte-mediated cytotoxicity against various equine target cells. Methods: 12 horses with sarcoid tumors and 15 control horses. Methods: Blood lymphocytes were cocultured in MLTC with allogeneic sarcoid cells (Mc-1, BayMc-1), equine te...
Rozhkov IuI, Okhapkin SK, Vorob'ev EG, Bezenko SP, Galimov IR.A stabilizing selection which is made in cattle according to phenotypic characters affects simultaneously a genetic character--the level of individual heterozygosity++. As a result animals with mean (modal) level of heterozygosity++ have the least probability of elimination. Similarly, the driving selection in pigs and horses leads to a change in both phenotypic characters and genetic character, the level of individual heterozygosity++. In this case the most heterozygous animals have the least probability of elimination.
Bombardi C, Grandis A, Gardini A, Sorteni C, Clavenzani P, Chiocchetti R.The activity of the gastrointestinal tract is regulated through the activation of adrenergic receptors (ARs). Since data concerning the distribution of ARs in the horse intestine is virtually absent, we investigated the distribution of β2-AR in the horse ileum using double-immunofluorescence. The β2-AR-immunoreactivity (IR) was observed in most (95%) neurons located in submucosal plexus (SMP) and in few (8%) neurons of the myenteric plexus (MP). Tyrosine hydroxylase (TH)-IR fibers were observed close to neurons expressing β2-AR-IR. Since β2-AR is virtually expressed in most neurons located...
van Haeringen H.Investigations for the presence of antibodies to red blood cell antigens were carried out in equine colostrum and serum. Material from 181 mares without clinical disease was tested. The object was to obtain information on the number of mares producing antibodies capable of inducing haemolytic disease in newborn foals. Of the mares 2.8% was positive for haemolysins. These mares are expected to be a risk for haemolytic disease. In addition agglutinating antibodies were identified in 39.2 per cent of the mares examined. It is not known whether or not these antibodies constitute a hazard for the f...
Lewczuk D, Metera-Zarzycka E.Many horse breeds in the world are reserved as genetic resources; however, their characteristics seem to be insufficiently clarified, especially in terms of horse performance. Two jumping ability evaluation methods have been used to compare different types of performance breeds and on this basis their applicability for precision phenotyping has been determined. Methods: Jumping data of 186 young Polish Warmblood stallions (27 with an endangered status) bred for sport and multipurpose use was collected during their performance tests organised under identical environmental conditions following t...
Komárková M, Bartošová J, Dubcová J.We present a study focused on those factors influencing dominance position in young horses, with emphasis on the role of the mother. Horses, as other group-living polygynous mammals, form stable linear dominance hierarchies based on agonistic interactions. Higher dominance positions are believed to be connected, in both sexes, to better condition and higher reproductive success. Many variables play a role in forming the dominant-submissive relationships between horses; however, the maternal effect on the dominance position of the offspring still remains unclear, as do the possible mechanisms o...
Kalmykov NP.The first data on polymorphism and preadaptation of the Pleistocene horses in the mountains surrounding Lake Baikal are presented. It has been shown that disregard of intraspecific polymorphism leads to unreasonable ignoring of their diversity, phylogenetically false constructions, and incorrect interpretation of natural environment.
