427Q ISB

Mailing address:
661 North Pleasant Street
University of Massachusetts
Amherst, MA 01003

Fax: 413-545-6326


M.S./Ph.D.: University of Minnesota
DVM: University of Lisbon, Portugal
Postdoctoral Training:
University of Minnesota
University of Ottawa
Cornell University

Honors and other distinctions:
AID, Fulbright, NATO, Rockefeller Fellow
Phi Zeta, Kappa Chapter
Diplomate of the American College of Theriogenology

Research & Teaching

Equine Reproductive Services

Dr. Gradil is dedicated to providing comprehensive breeding and reproductive care for your horse.

Equine Reproductive Services include:

  •  Breeding management of mares
  •  Fertility evaluation of mares
  •  Twin reduction in mares
  •  Stallion services and embryo transfer
  •  Innovative Intrauterine Devices (IUDs) used to modulate the reproductive cycle
Image of a horse IUD next to a ruler showing it is approximately one inch wide.

Why give horses pharmaceuticals to control estrus behavior, when they can produce their own progesterone? Inert IUDs - not coated with any drugs - cause a state of pseudo-pregnancy – absence of estrus = good behavior - in the mare for extended periods of time.

Dr. Gradil’s innovations continue with his development of a novel IUD. The IUD self-assembles into a triangular shape and once inserted it stays in place. With its small size both insertion and removal are very easy.  Its presence in the uterus can be monitored externally using a portable metal detector - similar to the ones used at airports. At the end of the performance season, the magnetic IUD can easily be retrieved from the uterus using a magnetic wand.

Shown here is the image of a 16 day old pregnancy in a 20 year old mare with multiple uterine cysts inseminated with frozen semen. This mare had an uterine device for 5 months, before it was removed in the fall of the previous breeding season.

Does the device affect future fertility? It does not. Shown here is the image of a 16 day old pregnancy in a 20 year old mare with multiple uterine cysts inseminated with frozen semen. This mare had an uterine device for 5 months, before it was removed in the fall of the previous breeding season.   


ANIMLSCI 421 - Wildlife Reproduction

This course explores comparative reproductive biology in terrestrial and marine wildlife and domesticated animals. It will encompass lectures, open discussion, and problem-based learning built on cases and experiences acquired in the field, literature, lecture topics and discussions. Topics will include: i) Functional Anatomy ii) Embryology iii) Reproductive Endocrinology and Life cycles iv) Reproductive Technologies v) Chemical and Physical Restraint of Animals vi) Problems and Policy Associated with Endangered Species vii) Management of Wildlife in National Parks, Game Ranches and Zoos viii) Contraception ix) Conservation techniques to solve problems of environmental change and international development; human-wildlife conflict x) Careers and Training/Job opportunities. This course fulfills the Animal Science major reproduction requirement.

Note: This course is offered during the Spring semester and online during the first Summer Session. Register for the online summer course through Continuing and Professional Education.

ANIMLSCI 445A - Equine Reproduction Lab

Equine Reproduction will provide understanding and hands-on opportunity in equine reproduction. Specifically, semen collection, evaluation and processing practice; discussion in mare breeding management and use of hormones; preparation of the mare for breeding; modulation of the estrous cycle; contraception; introduction to embryo transfer. Additionally, the mares in the breeding program at the UMass will be worked-on during laboratories and students will be able to participate in teasing and decision-making on breeding management and assisting in foaling. Client based cases may also be introduced during lab sessions.

ANIMLSCI 373 - Equine Diseases and Health Management

Topics: Common diseases in horses; Common pharmaceuticals administered by your veterinarian; Vaccinations; Internal parasites and their control; Lameness; Selected orthopedic problems; Spinal anatomy and disorders; Carpal and metacarpal disorders; Shoulder disorders; Disorders of the fetlock and pastern; Disorders of the forefoot; Disorders of the hind limb; Oral cavity; Digestive cavity; Anatomy of the gastrointestinal track; Equine colic; Choke; Feeding of the special needs horse; Caring for the older horse; Newborn Foal; Foal disorders

Note: Possible hands on and demonstration opportunities at the barns: General handling; Physical examination; Record keeping; Coggins testing; Vaccination - Injection sites; Deworming; Ongoing clinical cases at the barn; Dental care; Castration; Lameness; Hoof care and shoeing; Lyme snap test; Acupuncture.

ANIMLSCI 521- Physiology of Reproduction
Comparative aspects of anatomy, embryology, endocrinology and physiology of reproduction and lactation.


Intrauterine Devices (IUDs) used to modulate the Reproductive Cycle and as Contraceptives.
IUD application for humans, domestic animals and wildlife

Solving Problems With The Pearl Pod - The Chronicle of the Horse

Inert - Unmedicated device - Mechanical effect only
Regulate/modulate the estrous cycle (equine)
Synchronization of estrus for embryo transfer (equine)
Active - Medicated device - Progesterone embedded
Shorten spring transition (equine)
Active - Medicated device - Levonorgestrel embedded (humans)
Active - Medicated device - Cu2+
RFID - Tracking/Monitoring

The initial goal was to improve control of female horse behavior. Female horses can behave erratically during their mating season, which can be disturbing or even dangerous to riders. The traditional remedy has been to insert a glass marble into the uterus, which stimulates progesterone secretion and calms behavior. But marbles are known to fall out easily, and their presence or absence can’t be easily detected. Feeding exogenous progesterone is costly, labor intensive and a potential endocrine disruptor, with serious consequences for the operator.

We have developed a simple solution to this problem based on an IUD made up of plastic-coated magnets, which self-assemble into a shape that keeps them from falling out, while at the same time their individually small size makes insertion and removal very easy. The presence of this IUD can be confirmed by ultrasound, or easier yet, they can be detected by simply holding a hand-held metal detector to the mare’s abdomen. At the end of the mating season the magnets can easily be retrieved from the uterus using a magnetic retriever. The IUDs should be useful not only for behavior control, but also to allow horse breeders to synchronize horses for example, for embryo transfer.

We plan to develop modified devices that include traditional copper or progesterone-eluting coatings to make these IUDs capable of providing reliable contraception. Because of their simple design, ease of insertion and ease of removal, these devices could be used for controlling animal populations in the wild, and to provide a non-surgical means of controlling fertility in pets. These IUDs would offer considerable advantages over currently-available human IUDs, which can be challenging to remove, sometimes requiring the device be torn from the uterus wall. In addition, over 100,000 IUDs in the U.S. fall out each year; current IUDs have a string coming out of the cervix to assure they are still there. The IUD we have developed would need no string, because a specially developed metal detector app will allow a woman to easily confirm the IUD is still in place with her cell phone.

Other activities

Founder in 1996 and present co-owner of @email a mailing list in small animal reproduction. The list is subscribed by over 250 leading names in the field worldwide facilitating access to expert opinion and contacts to veterinary colleges and reproduction specialty practices around the world.

A person poses for a photo stationary on a motorbike.

Summer Practicum

ANIMLSCI 298 Practicum/Internship, (1 cr ) Shadow Equine Veterinarian Dr. Carlos Gradil at the UMass Equine Reproduction Clinic for 2 weeks in June or July.

Continuing Education Assisted Equine Reproduction for Prevet/Veterinary Students: This CE shadow opportunity is designed to provide exposure to equine reproduction. Dr. Gradil will discuss principles and mechanisms of normal and abnormal aspects of equine reproduction and current approaches to reproductive care and management. The aim is to provide the participant with current knowledge of assisted reproduction in a modern equine industry. Content includes functional anatomy, reproductive life cycles and terminology, discussion of breeding management, common causes of infertility and assisted reproductive technologies i.e., ultrasound, semen processing etc.. Note: Mares in the breeding program at the Umass Hadley Farm will be worked-on and participants will take part in teasing and decision-making on breeding management. Client based cases may also be introduced during lab sessions. 

Students must make arrangements with Dr. Gradil for the specific 2 week time period that they would like to participate in the internship. Register for the summer practicum using HandShake. Complete an online Experience form. Click on the Career Center tab on the top right, then click Experiences, then Request an Experience. Under Details, under Experience Type, select Internship for Credit – For Domestic and International Undergraduates; select a Term, and include your placement details, learning objectives and academic project, if you are getting credit. Once you complete and submit your Experience form, Central Career Services staff will review the form and then forward it to your faculty sponsor for approval.

How Undergraduate Internships for Academic Credit Work


Please contact me via email to make an appointment.


ANIMLSCI 373 - Equine Diseases and Health Management
ANIMLSCI 421 - Wildlife Reproduction
ANIMLSCI 445A - Equine Reproduction Lab
ANIMLSCI 521- Physiology of Reproduction