Dr. Patrick M. McCue

Mare

Almeida J, Ball BA, Conley AJ, et al. Biological and clinical significance of anti-Müllerian hormone determination in blood serum of the mare.  Theriogenology 2011 (in press).  

Take Home Message:  Levels of AMH do not vary throughout the estrous cycle of the mare or throughout pregnancy.  Concentrations of AMH appear to be higher in mares with granulosa cell tumors than cycling or pregnant mares.

Broaddus CC, Balasuriya UB, White JLR, et al.   Evaluation of the safety of vaccinating mares against equine viral arteritis during mid or late gestation or during the immediate postpartum period. J Am Vet Med Assoc 2011;238:741-750.

Take Home Message: It appears to be safe to vaccinate healthy pregnant mares against equine arteritis virus up to 3 months before foaling and during the immediate postpartum period. Vaccination during the last 2 months of pregnancy was associated with a risk of abortion.

Cocchia N, Paciellob O, Auletta L, et al. Comparison of the cytobrush, cotton swab, and low-volume uterine flush techniques to evaluate endometrial cytology for diagnosing endometritis in chronically infertile mares. Theriogenology (in press).

Take Home Message: The cytology brush and low volume lavage were preferred over the cotton swab for collection of cytology samples. Interpretation of the cytology specimens (number of white blood cells/high powered field or the ratio of white blood cells to uterine epithelial cells) may be more important than the technique used to obtain the specimen.

Ferris RA, Dern K, Veir J, et al. Development of a broad range qPCR assay to detect and identify fungal DNA in equine endometrial samples.  Clin Theriogenology 2011;3:375.

Take Home Message: Molecular techniques are becoming available in veterinary medicine to detect the presence of DNA of potential pathogens. The qPCR for fungal DNA was determined to be rapid and able to identify fungal organisms in instances where traditional microbial culture and biochemical analysis could not.

Köllmann M, Rötting A, Heberling et al.  Laparoscopic techniques for investigating the equine oviduct.  Equine Vet J 2011;43:106-111.

Take Home Message:  Catheterization of the oviduct can be accomplished using a flank laparoscopic approach and the oviduct can be subsequently flushed to evaluate patency.  This technique can provide diagnostic information regarding oviductal blockage in subfertile mares.

Niemantsvertriet-Murton AS, Paccamonti D, Eilts BE, et al. Use of acupuncture to induce cyclicity in anestrous mares.  J Equine Vet Sci 2011;31:97-102.

Take Home Message:  Within the parameters of this study, there was no significant difference in average interval to first ovulation of the year between acupuncture treated and control mares.  Additional controlled studies are clearly needed to provide more information on the efficacy of acupuncture on follicular development and on evacuation of uterine fluid.  

Overbeck W, Witte TS, Heuwieser W. Comparison of three diagnostic methods to identify subclinical endometritis in mares.  Theriogenology 2011;75:1311-1318. 

Take Home Message:Cytology or culture alone were associated with a high incidence of ‘false negative’ results. A combination of cytology and culture improved diagnostic capability. The cytology brush was the preferred method of sample collection. Infection with E. coli was not associated with inflammatory changes on cytology, whereas infection with S. zooepidemicus was associated with a positive cytology in 40 % of cases.

Stallion

Brito LC, Greene LM, Kelleman A, et al.  Effect of method and clinician on stallion sperm morphology evaluation.  Theriogenology 2011;76:745-750.

Take Home Message:  Wet mount preparations with phase contrast microscopy appeared more sensitive to identification of abnormal sperm compared to stained smears.  Smearing semen samples for staining increased the proportion of detached heads.  The Papanicolaou stain was not suitable for stallion sperm.  A significant difference was noted among clinicians, suggesting that consistent training is important.

Love CC.  Relationship between sperm motility, morphology and the fertility of stallions.  Theriogenology  2011;76:547-557.

Take Home Message: The percentage of mares pregnant on their first cycle was the only fertility measureable to discriminate among high, average and low fertility groups.  The sperm qualities most highly correlated with fertility included percent total sperm motility and percent morphologically normal sperm.

Monteiro GA, Papa FO, Zahn FS, et al. Cryopreservation and fertility of ejaculated and epididymal stallion sperm.  Anim Reprod Sci 2011;127:197-201.

Take Home Message: The total number of sperm following an epididymal collection (25 billion) is greater than the number of sperm in the average ejaculate from a given stallion (7.8 billion).  There was no difference in post-thaw motility parameters or in pregnancy rates between groups, although there was a trend for pregnancy rates to be highest in the epididymal semen processed immediately.  Collection and cryopreservation of epididymal semen immediately after castration or after 24 hours of cooling can yield breeding doses for future use in the event of a catastrophic injury to a stallion. 

Summers-Lawyer KA, Go YY, Lu Z, et al.   Response of stallions to primary immunization with a modified live equine viral arteritis vaccine.  J Equine Vet Sci 2011;31:129-138. 

Take Home Message:  There was no evidence of persistence of vaccine virus in the reproductive tract of first-time vaccinated stallions. There was also no evidence of lateral transmission of vaccine virus to in-contact horses.  A transient, low level of viral activity was detected in semen.  Consequently it is recommended to withhold use of semen for 14 days after first-time vaccination to minimize risk of transmission of vaccine virus and eliminate potential for vaccine virus in frozen semen

Embryo Transfer and Assisted Reproduction

Choi YH, Velez IC, Riera FL, et al. Successful cryopreservation of expanded equine blastocysts.  Theriogenology 2011;76:143-152. 

Take Home Message: Aspiration of blastocoele fluid prior to vitrification of a large embryo can result in a viable embryo after thawing (warming) and a pregnancy after transfer.  This technique appears to be a significant step forward for equine embryo transfer.

Hinrichs K.   Biopsy and vitrification of equine expanded blastocysts.  Clinical Theriogenology 2011;3:314-317. 

Take home message: Biopsy of expanded blastocyst embryos was possible and did not compromise embryo viability. Genetic analysis was accurate for sex determination (compared to eventual foal) and a ‘work in progress’ for HERDA and HYPP. Preimplantation genetic diagnosis (PGD) may soon become a viable clinical procedure.

Riera F.  General techniques and organization of large commercial embryo transfer programs. Clinical Theriogenology 2011;3:318-324.

Take Home Message: A breeding soundness evaluation should be performed on each donor and recipient mare.  Recipient mare selection and management is critical to success.  Recipient synchrony with donor ranges from 0 to -4 days.

Case Reports and Abstracts

Lear TL, Raudsepp T, Lundquist J, et al. A chromosome translocation [64,XX,t(2:13)] in a Thoroughbred mare with repeated early embryonic loss.  J Equine Vet Sci 2011;31:240.

Take Home Message:  Birth of a live foal does not rule out possibility of a chromosomal issue.  Karyotype with additional tests may be required to identify a chromosomal problem (i.e. a translocation).

Robinson KA, Manning ST.  Premature lactation and retention of a mummified fetus with live birth of the co-twin in a primiparous Morgan mare.  Can Vet J 2011;52:423-425.

Take Home Message: Premature lactation may be associated with loss of one fetus of a twin pregnancy.