R M Kenney

University of Pennsylvania, Philadelphia, Pennsylvania, United States

Are you R M Kenney?

Claim your profile

Publications (65)105.89 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Four ovariectomised mares were used as recipients for embryo transfer. They were given 300 mg progesterone in oil intramuscularly daily for five days before transfer and were subsequently maintained on this treatment. Embryos were recovered and transferred non-surgically seven or eight days after the donor mares had ovulated. A total of seven embryos were transferred and pregnancy was established in three of the four recipients. At the time of writing, these pregnancies have developed normally to Days 155, 92 and 82 of gestation, respectively.
    Equine Veterinary Journal 06/2010; 17(S3):74 - 75. · 2.29 Impact Factor
  • R. M. KENNEY
    Equine Veterinary Journal 06/2010; 25(S15):42 - 46. · 2.29 Impact Factor
  • KATRIN HINRICHS, R. M. KENNEY, D. C. SHARP
    [Show abstract] [Hide abstract]
    ABSTRACT: Ovariectomised, progesterone-treated mares were used to test the effect of two different durations of progesterone treatment on pregnancy rate after embryo transfer, and to examine the effect of duration of progesterone treatment on the secretion of uterine proteins. Ovariectomised mares were assigned to one of two groups: ‘synchronous’ mares, given progesterone from two days after the date of ovulation of a potential donor mare; or ‘asynchronous’ mares administered progesterone from five to seven days before the predicted date of ovulation of a potential donor mare. The day of ovulation of a given donor mare was designated Day 0. Four procedures were performed using both synchronous and asynchronous mares: no transfer; sham transfer at Day 7; embryo transfer at Day 7 resulting in pregnancy on Day 14; and embryo transfer at Day 7 resulting in no pregnancy at Day 14. Uterine fluid was collected from the recipient mares either at Day 7, or seven days after embryo, or sham, transfer (Day 14). This schedule resulted in uterine fluid being recovered after the mares had been treated with progesterone for three different durations: five days (synchronous recipients flushed at Day 7); 12 to 15 days (synchronous recipients flushed at Day 14 or asynchronous recipients flushed at Day 7); and 19 to 21 days (asynchronous recipients flushed at Day 14). Total concentration of protein in uterine fluid tended (P= 0.08) to increase with the duration of progesterone treatment, and the main effect of procedure also tended (P = 0.06) to affect protein content. Acid phosphatase content of uterine flushings was significantly (p<0.05) affected by duration of progesterone treatment, being ten-fold higher after 19 to 21 days of treatment than after five days of treatment. Characterisation of proteins in uterine fluid by two-dimensional polyacrylamide gel electrophoresis did not reveal striking qualitative differences in protein patterns, except for a protein apparent in uterine fluid from the two mares treated with progesterone for five days only (synchronous, no-transfer group). This protein was not observed at other stages.
    Equine Veterinary Journal 01/2010; 21:49-55. · 2.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper compares uterine involution in intact and ovariectomised embryo recipient mares after foaling. There was no difference in the rate of uterine involution between the two groups and on Day 1 post partum intact and ovariectomised mares both have degenerating microcaruncles in the Stratum compactum. At this time the endometrial glands are tortuous and distended along their entire length. By Day 7 post partum the only remaining evidence of the microcaruncle is an area of condensed stroma containing siderophages and a few other mononuclear cells and covered by an intact epithelium. By Day 10 to 11 the cystic glandular distention has resolved.
    Equine Veterinary Journal 01/2010; 21:56-58. · 2.29 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Testicular degeneration is a major cause of subfertility in stallions, although an aetiological diagnosis cannot be made in most cases. In the present study, autoimmune testicular degeneration was induced and evaluated in stallions by immunizing stallions with their own spermatozoa mixed with an adjuvant. The factors evaluated included changes in semen quality and testicular histology. A large decrease in sperm number and quality was observed in response to sperm autoantigens. An ELISA test specific for antisperm antibodies was developed which enabled antibody titres in serum, seminal plasma and accessory sex organs to be measured. Serum antibodies were characterized as being specific for spermatozoa by absorption studies and western blotting. The data obtained and the tests developed in the present study provide a better understanding of the disease in subfertile breeding stallions and the ability to diagnose the disease using ELISA. The results of a clinical trial demonstrate that there is a higher incidence of antisperm antibodies in subfertile stallions compared with fertile stallions. The results of the present study indicate that autoimmunity to spermatozoa plays a role in idiopathic subfertility in stallions. A potentially useful method for tentative diagnosis of autoimmune testicular degeneration in subfertile stallions was also developed.
    Journal of reproduction and fertility. Supplement 01/2000;
  • C C Love, R M Kenney
    [Show abstract] [Hide abstract]
    ABSTRACT: A variety of testicular insults can induce changes in the structure of spermatozoal chromatin, resulting in spermatozoal DNA that is more susceptible to acid-induced denaturation. The degree of change in the DNA can be measured using the sperm chromatin structure assay (SCSA). The SCSA measures the relative amounts of single- and double-stranded DNA after staining with the metachromatic dye, acridine orange. Here we used a stallion model (n = 4) to study the effects of scrotal heat stress on spermatozoal DNA. This model was created by insulating stallion testes for 48 h and collecting sperm daily thereafter for 60 days. Changes in the SCSA were then correlated with protamine disulfide content and protamine types and levels. Results of the SCSA indicated that the susceptibility of spermatozoal DNA to denaturation was dependent on the spermatogenic cell stage that the ejaculated sperm was in at the time of the heat stress. Spermatozoa with altered DNA had a decrease in the extent of disulfide bonding that was associated with an increase in the susceptibility of DNA to denaturation. However, there were no detectable changes in either the protamine type or level. Thus, in this model, decreased disulfide bonding is associated with an increased susceptibility of spermatozoal DNA to denaturation in the absence of protamine changes.
    Biology of Reproduction 04/1999; 60(3):615-20. · 4.03 Impact Factor
  • C C Love, R M Kenney
    [Show abstract] [Hide abstract]
    ABSTRACT: The relationship between fertility and susceptibility of sperm DNA to denaturation was determined in a group of 84 actively breeding, clinically fertile stallions. Susceptibility of DNA to denaturation was determined using the sperm chromatin structure assay (SCSA). The SCSA measures, mean of alpha-t (mean alpha t), standard deviation of alpha-t (SD alpha t), and the COMP of alpha-t (cells outside the main population)] were significantly correlated with the percentage seasonal pregnancy rate (SPR; mean alpha t, r = -0.24, P < or = 0.05; % COMP alpha t, r = -0.27, P < or = 0.05); percentage pregnant per first cycle (FCP; SD alpha t, r = -0.30, P < or = 0.01; % COMP alpha t, r = -0.42, P < or = 0.0001); and the percentage pregnant per cycle (PC; mean alpha t, r = -0.31, P < or = 0.01; SD alpha t, r = -0.32, P < or = 0.01; % COMP alpha t, r = -0.41, P < or = 0.0001). This study describes detectable intrinsic variation in sperm chromatin structure among fertile stallions (SPR, mean = 83%; FCP, mean = 58%; PC, mean = 57%) in an active breeding population (number of mares bred/stallion/year, mean = 37), in the absence of overt reproductive abnormalities and apparent diseases such that an increase in the susceptibility of sperm DNA to denaturation is associated with reduced fertility, both in terms of efficiency of reproduction (FCP and PC) and seasonal pregnancy rate (SPR). Both COMP alpha t and mean alpha t were useful indicators of fertility, with COMP alpha t being the only SCSA value able to identify mean differences between fertility groupings for SPR and FCP, and overall it was the most reliable indicator of fertility in this group of stallions. The SCSA is able to evaluate a compartment of the spermatozoa which is different from that of traditional tests for sperm quality such as motility and morphology.
    Theriogenology 10/1998; 50(6):955-72. · 2.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: An 8-year-old stallion was evaluated because of recurrent urinary tract infections and chronic intermittent urospermia. After extensive diagnostic testing, it was hypothesized that the stallion had a reflex dyssynergia of the bladder and urethral sphincter. Initial attempts to manage the urospermia included semen fractionation, semen collection after voluntary urination, and use of semen extenders. None of these efforts reliably yielded a quality ejaculate. Administration of imipramine hydrochloride (1.2 mg/kg of body weight, PO, 4 hours prior to semen collection) was initiated in an attempt to enhance bladder neck closure during ejaculation. This treatment, combined with voluntary urination prior to ejaculation, resulted in ejaculates containing little or no urine. Using this protocol, 19 of 20 mares bred during the subsequent 2 years became pregnant. By the third year, the bladder dysfunction had progressed, and the urospermia was no longer manageable. Bladder catheterization, followed by manual expression of the bladder per rectum, were necessary prior to each semen collection to obtain a urine-free ejaculate. Three-and-a-half years after initial examination, transitional cell carcinoma of the bladder with metastasis was identified, and the stallion was euthanatized. It is not known whether the transitional cell carcinoma was related to the dysfunctional bladder. Imipramine hydrochloride did not eliminate, but did reduce, the frequency and degree of urospermia in the affected stallion for approximately 2 years.
    Journal of the American Veterinary Medical Association 01/1996; 207(12):1602-6. · 1.72 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, 2 stallions were immunised with their own spermatozoa to ascertain whether an antisperm autoantibody response could be mounted. The results demonstrated that the stallion can recognise and respond to sperm autoantigens by producing circulating antisperm antibodies, primarily of the IgG class. Such autoantibodies appeared 2-4 weeks after inoculation and persisted for 6-20 weeks. Immunochemical characterisation by western blot identified two major sperm autoantigens, with molecular weights of 70 kD and 62 kD. Control pony stallions immunised with adjuvants alone failed to exhibit such antibodies. IgA antisperm antibodies were measurable in seminal plasma of both stallions. We suggest that, as in other species, autoimmunity to spermatozoa may play a role in idiopathic subfertility in stallions.
    Equine Veterinary Journal 04/1994; 26(2):148-51. · 2.29 Impact Factor
  • Source
    C C Love, S M McDonnell, R M Kenney
    [Show abstract] [Hide abstract]
    ABSTRACT: A Thoroughbred stallion with erectile dysfunction following paraphimosis was managed to allow consistent ejaculation. Ejaculation was elicited in this stallion by applying manual stimulation to the base of the penis. This technique allowed consistent ejaculation, and the stallion was able to return to natural service. Historically, stallions with this degree of penile dysfunction have been considered incapable of ejaculation and unable to continue as breeding animals.
    Journal of the American Veterinary Medical Association 06/1992; 200(9):1357-9. · 1.72 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Two mature breeding stallions were evaluated because of specific ejaculatory dysfunction, and each was found to have aortic-iliac thrombosis occluding 60 to 70% of the aortic lumen. In each case, the stallion had strong libido, normal mounting, and vigorous initial thrusting. With continued exertion, thrusting became weak and dismount was awkward. Treatment aimed at maximizing sexual arousal before mounting and reducing hind limb pain and exertion during breeding allowed these stallions to continue breeding. A program of gradually increasing daily exercise also was associated with improved breeding performance during subsequent breeding seasons. In cases of specific ejaculatory dysfunction, aortic-iliac disease should be included among the differential diagnoses.
    Journal of the American Veterinary Medical Association 05/1992; 200(7):954-7. · 1.72 Impact Factor
  • T L Blanchard, R M Kenney, P J Timoney
    [Show abstract] [Hide abstract]
    ABSTRACT: Equine venereal infections of concern in the United States include EHV-3, T. equigenitalis, P. aeruginosa, and K. pneumoniae. Stallions may also harbor EAV in the genital tract and transmit the virus to mares during coitus. With the exception of EHV-3, the stallion generally remains asymptomatic while transmitting infections to mares during breeding. Methods for diagnosis, treatment, and control of these infections are discussed.
    Veterinary Clinics of North America Equine Practice 05/1992; 8(1):191-203. · 1.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Histological features of the endometrium, as assessed in biopsy samples, were related to Standardbred mare genotypes for transferrin, esterase (as a control) and equine leucocyte antigens (ELA). Pathological changes were found more frequently in each successively older age group of mares. Among mares aged 6-19 years, there were significant pathologic changes on first examination following an infertile breeding season for 46 of 90 (51%) of transferrin homozygotes and 50 of 146 (34%) of transferrin heterozygotes. The difference between the two groups was significant for the total data (chi 1(2) = 6.56, P = 0.010) and when the data were stratified for mare age at biopsy (chi 1(2) = 7.33, P = 0.0068). The effect of transferrin was similar in both trotters and pacers, especially for frequent genotypes commonly found in horses of both gaits. There was no effect of esterase and, in a smaller set of ELA-typed mares, no significant effect of ELA genotype on uterine biopsy category. Transferrin has a well-established microbiostatic and biocidal effect. Conceivably, heterozygotes for some combinations of transferrin variants could have a slower natural rate of endometrial deterioration than homozygotes.
    Journal of reproduction and fertility. Supplement 02/1991; 44:275-82.
  • [Show abstract] [Hide abstract]
    ABSTRACT: A total of 174 stallions were subjected to a standard fertility examination and classified as fertile, subfertile or sterile. All stallions were phenotypical males involved in breeding programmes with no detectable abnormalities in their reproductive organs. Fertile stallions had no history of any breeding problem. Subfertile stallions were referred with a history of a breeding problem that was subsequently determined not to be attributable to the mares or infectious diseases. They were divided into chromosomally normal and abnormal groups on the basis of karyotype. The relative DNA content of lymphocytes (DI) was estimated by flow cytometry to relate this parameter with chromosome status. Of 62 completed karyotypes, 44 were normal diploid stallions and 18 had chromosomal defects, including mosaics with sex or autosomal deletions or duplications. The seasonal pregnancy rates for the subfertile chromosomally defective and subfertile chromosomally normal stallions were similar but were less than half of those of the fertile stallions. With the present limited data, no association was noted between DI and pregnancy rate. The mean DI for the subfertile stallions with chromosome defects was not different from those of the fertile and the subfertile chromosomally normal stallions. However, the DI for a mosaic stallion with sex chromosome deletion was lower than the DI for the fertile stallions. Extremely high and low values of the DI may be useful for flagging potential subjects for detailed chromosome investigation. The DI also was correlated negatively (P less than 0.002) with progressive sperm motility.
    Journal of reproduction and fertility. Supplement 02/1991; 44:69-75.
  • C C Love, M C Garcia, F R Riera, R M Kenney
    [Show abstract] [Hide abstract]
    ABSTRACT: The semen of 26 stallions, 2-20 years of age, was collected once a day for 7 consecutive days to determine daily sperm output (DSO). After the last collection, 17 stallions were castrated. Testicular volume was estimated using two methods. Length, width, height, of each testis were measured by caliper. Length, width, height, cross-sectional area and circumference at the widest point of the testis were measured by ultrasonography. Both caliper and ultrasound measurements were first made in the live animal, and again in vitro. There were no differences in these measurements because of method or condition of the animal, i.e., whether the measures were taken in the live animal or after castration. The volume of an ellipsoid (4/3 pi abc, a = height/2, b = width/2, c = length/2) is introduced as a method of accurately estimating testicular volume (r = 0.99) as well as predicting DSO (r = 0.92) in the stallion. The authors of this report suggest that this estimation can be performed by substituting values derived by ultrasonography or calipers.
    Journal of reproduction and fertility. Supplement 02/1991; 44:99-105.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The association of equine granulosa-theca cell tumors with atrophied contralateral ovaries and abnormal estrous cycles suggests that these tumors produce hormones that affect pituitary gonadotropin production. Because inhibin, a heterodimer protein secreted by granulosa cells, decreases FSH production, we examined the presence of inhibin alpha- and beta A-subunits and their mRNAs in ovarian tumors obtained from three mares. These tumors contained neoplastic cords and nodules, multiple fluid-filled cysts, and a predominance of neoplastic granulosa cells. Reduced proteins from tumor-conditioned media were analyzed by electrophoresis and immunoblotting using antibodies directed against peptide fragments of the alpha- and beta A-chains of porcine inhibin. Specific bands at 50-kDa and 36-kDa for the inhibin alpha-subunit and at 44 kDa and 13 kDa for the inhibin beta A-subunit were observed in these tumors. Northern blot hybridization of 32P-labeled rat inhibin alpha- and beta A-subunit complementary RNAs to total RNA from each tumor revealed predominant bands of activity in all three tumors at 1.5 and 7 kb for the alpha- and beta A-subunit mRNAs, respectively. These results demonstrate that equine granulosa-theca cell tumors express the mRNAs for inhibin alpha- and beta A-subunits and also secrete inhibin subunits that could potentially affect gonadotropin production in afflicted mares. Furthermore, cells derived from these tumors may provide a useful model for understanding inhibin gene regulation and ovarian tumorigenesis.
    Biology of Reproduction 01/1991; 43(6):1050-7. · 4.03 Impact Factor
  • K Hinrichs, E D Watson, R M Kenney
    [Show abstract] [Hide abstract]
    ABSTRACT: A functional corpus luteum was found in the ovary contralateral to the ovary with a granulosa cell tumor in a 24-year-old Standardbred mare. The mare was ovariectomized because she was to be used as a jump mare for collection of semen from stallions. The blood concentration of progesterone was 2.2 ng/ml, and the luteal tissue progesterone concentration was 6.3 micrograms/mg. Atrophy of the contralateral ovary is one of the major signs used in diagnosis of granulosa cell tumor; however, our findings indicate that the ovary contralateral to a granulosa cell tumor is not invariably nonfunctional.
    Journal of the American Veterinary Medical Association 11/1990; 197(8):1037-8. · 1.72 Impact Factor
  • K Hinrichs, D F Kenney, R M Kenney
    [Show abstract] [Hide abstract]
    ABSTRACT: Two experiments were conducted to investigate methods for aspirating oocytes from immature preovulatory follicles in the mare. In Experiment 1, the ovary was manipulated per rectum and the follicle was punctured by a needle introduced through the flank. Suction was provided by either a syringe or by a vacuum pump connected to the needle via tubing. The preovulatory follicle was aspirated when it reached a diameter of 32 +/- 2 mm (Group A); 37 +/- 2 mm (Group B); or 42 +/- 2 mm (Group C). There was no significant difference in oocyte recovery rates between the two methods (7/24 vs 3/19). Oocyte recovery rates were higher for Groups B and C (5/14 and 4/12, respectively) than for Group A (1/17; P < 0.05). In Experiment 2, the ovary was held against the internal abdominal wall by the hand inserted into the abdomen via a vaginal incision, and the follicle was flushed after aspiration. Recovery rates were 9/13 (69%) for mares treated with human chorionic gonadotrophin (hCG) and 15/21 (71%) for unstimulated mares. This difference was not significant. The oocyte recovery rate for unstimulated follicles (average diameter 39.7 mm) in Experiment 2 was significantly higher than those for Group B and Group C in Experiment 1 (P < 0.05).
    Theriogenology 07/1990; 34(1):107-12. · 2.08 Impact Factor
  • C C Love, P J Strzemienski, R M Kenney
    [Show abstract] [Hide abstract]
    ABSTRACT: Serum concentration of ampicillin, a semisynthetic penicillin, was measured in mares at various time intervals up to 24 hours after intrauterine infusion of 3 g of ampicillin. Blood samples were drawn immediately before infusion and at 1-, 4-, 10- and 24-hour intervals after infusion. At postinfusion hour 24, two endometrial biopsy specimens were obtained to measure endometrial concentrations of ampicillin. Blood was drawn twice as part of the 24-hour postinfusion sample collection, once before removal of the biopsy specimens and again 5 minutes after removal of the biopsy specimens. After drug infusion, more diestrous mares had detectable serum ampicillin concentration than did estrous mares for all samples, except the 24-hour prebiopsy sample. None of the 24-hour prebiopsy serum samples had detectable ampicillin concentration, but ampicillin was detected in the serum of 4 of 5 diestrous mares after endometrial biopsy. Endometrial concentrations of ampicillin were detectable at postinfusion hour 24 in estrous and diestrous mares, but were not different. All 24-hour biopsy specimens had ampicillin concentrations greater than the ampicillin minimal inhibitory concentration.
    American Journal of Veterinary Research 03/1990; 51(2):197-9. · 1.35 Impact Factor
  • Equine Veterinary Education - EQUINE VET EDUC. 01/1990; 2(3):121-122.

Publication Stats

486 Citations
105.89 Total Impact Points

Institutions

  • 1981–2010
    • University of Pennsylvania
      • School of Veterinary Medicine
      Philadelphia, Pennsylvania, United States
  • 1990
    • Tufts University
      • Department of Medicine
      Medford, MA, United States
  • 1987
    • Texas A&M University
      College Station, Texas, United States