DIGEST Ca.Uky.Edu/Equine ❙ Thehorse.Com ❙ MAY 2015
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Bluegrass Equine DIGEST CA.UKY.EDU/EQUINE ❙ THEHORSE.COM ❙ MAY 2015 Does Season Impact Old Articles of Interest Horses’ Immune Function? McCue, Squires Publish Equine Embryo Transfer easons impact horses in a variety Researchers know that season im- Manual of fairly obvious ways: Maybe pacts horses’ body weight, voluntary S your horse drops some weight feed intake, and adrenocorticotropic Emerging Equine Diseases: in the winter due to the cold, blows up hormone (ACTH, which plays a role in What You Should Know like a balloon on spring grass, gets a bit pituitary pars intermedia dysfunction lazy in the summer heat, or becomes [PPID], or equine Cushing’s disease) Graduate Student Spotlight: frisky as cooler fall temperatures ar- levels, among others. Kristin M. Pfahl rive. But did you know that season They’ve discovered seasonal changes Integrated Parasite Control: can also impact horses in less appar- in other species, too. Siard said scien- How to Strike a Balance ent internal ways, such as their im- tists have determined that baboons’ mune response? Researchers from the C-reactive protein (an inflammatory Weed of the Month: University of Kentucky Gluck Equine cytokine; cytokines are “messenger Hemp Dogbane Research Center, in Lexington, recently molecules” by which cells of the im- sought to determine whether age can mune system signal and instruct one Gluck Center Collaborates intensify those seasonal effects. another) and interleukin-6 (another in- With UK Libraries, Keeneland In a presentation April 30, Melissa flammatory cytokine) levels are lower Library for Arabian Roots Siard, a PhD candidate working under in December compared to July. Exhibit the direction of Amanda Adams, PhD, So she and her colleagues wanted to at the Gluck Center, presented findings determine if aged horses experience UK Veterinary Diagnostic Lab from a study investigating season’s im- similar fluctuations. The team sought Part of Larger Animal Health pact on senior horses’ immune function. to identify the relation between season Monitoring Network and lymphocyte (cells that govern the body’s immune response) proliferation UK Lecture Series Conver- and function. Further, because they sation With Reiner Shawn knew that cortisol (the “stress” hor- Flarida Held April 27 mone) and ACTH levels vary seasonally, UK Equine Farm and Facilities they investigated whether hormone lev- Expo to be Held June 2 els impact immune function. The team employed eight senior and Follow Us on Twitter eight adult horses for their study and collected blood monthly from each ani- The Equine Genetic Toolbox mal. They also tested the aged horses for PPID to compare affected and unaf- Upcoming Events fected horses’ immune responses. For their first objective, the team found that: highest in May and July and lowest ■ Both groups of horses collectively in December; had higher lymphocyte prolifera- ■ Older horses had higher average tion (immune cells’ ability to divide IFN-γ and tumor necrosis factor-α in response to a stimulus, such as a (TNF-α, another cytokine) produc- pathogen) in October and November tion as well as a higher percentage of and lower lymphocyte proliferation lymphocytes producing IFN-γ and in May. TNF-α than adult horses; ■ Old horses’ interferon-gamma ■ Old horses’ TNF-α levels were highest (IFN-γ, another type of inflamma- in August and October and lowest in In the study, senior horses' inflammation levels tory cytokine) production was high- December and January; and increased in the spring and their lymphocyte est in March, June, and October ■ There were no significant differenc- proliferation increased in the fall. and lowest in January, August, and es in immune response between old ISTOCK.COM December; adult horses’ levels were non-PPID and PPID horses. 1 Bluegrass Equine Digest ❙ ca.uky.edu/equine ❙ TheHorse.com ❙ May 2015 Immune Function Conclusions Based on their results, the team reached several conclusions, Siard said, MASTHEAD Siard said these results indicate that including: both age and season impact horses’ lym- ■ Senior horses had increased inflam- ■ University of Kentucky Ag Equine phocyte function. She said she suspects mation compared to adults; Programs ■ these impacts could be due to a number The older horses’ inflammation levels Jenny Evans, MFA, co-managing editor of factors, including stress hormone increased in the spring and lymphocyte and interim executive director of the levels, vitamin D and melatonin levels, proliferation increased in the fall; and Gluck Equine Research Foundation, available forage sources, temperature, ■ Adult horses did not have increased [email protected] and more. lymphocyte proliferation compared to Holly Wiemers, MA, APR, co-managing For their second objective, the team seniors. editor and communications direc- tor of UK Ag Equine Programs, holly. determined that: Siard said future research could [email protected] ■ Cortisol levels did not vary signifi- help determine whether seasonality cantly for old or young horses, but did could impact senior horses’ response to ■ Bluegrass Equine Digest vary seasonally with increases in April vaccination. Advisory Board for old horses and in April and July for “The seasonality of lymphocyte func- Bob Coleman, PhD, PAS, associate profes- adult horses; and tion could indicate when horses are sor, director of undergraduate studies ■ There was a trend toward age impact- more likely to be susceptible to disease as for equine science and management ing ACTH levels, but both groups ex- well as when inflammatory disorders are and extension horse specialist perienced a significant increase in more likely to flare up,” she explained. David Horohov, MS, PhD, interim chair of UK's Department of Veterinary Science ACTH levels in October. “This research provides a foundational and interim director of the UK Gluck These seasonal hormone changes understanding of the fluctuations of the Equine Research Center suggest a possible relationship with im- immune systems of senior horses, in Ray Smith, PhD, professor and forage mune seasonal changes. However, the hopes that we can better manage their extension specialist in the department researchers found few correlations be- health by predicting in advance when of plant and soil sciences Ed Squires, PhD, Dipl. ACT (hon.), profes- tween the hormones and immune mark- they may be immunocompromised.” sor, UK Gluck Equine Research Center ers, suggesting hormones do not play a Jill Stowe, PhD, director of UK Ag Equine strong role in regulating immune func- >Erica Larson is the news editor for The Horse Programs and associate professor tion seasonally. and TheHorse.com. in the department of agricultural economics ■ Bluegrass Equine Digest McCue, Squires Publish Equine Embryo Editorial Committee Craig Carter, DVM, PhD, Dipl. ACVPM, Transfer Manual director and professor of the UK Veterinary Diagnostic Laboratory Laurie Lawrence, PhD, professor in atrick McCue, DVM, PhD, Dipl. ACT, a professor at Col- the department of animal and food Porado State University (CSU), and Edward Squires, MS, sciences PhD, Dipl. ACT (Hon.), a professor at the University of Ken- Krista Lea, MS, assistant coordinator of tucky Gluck Equine Research Center, recently teamed up to UK’s Horse Pasture Evaluation Program publish a manual titled Equine Embryo Transfer. in the department of plant and soil Targeted toward veterinary practitioners and students, sciences William W. Witt, PhD, professor emeritus the manual is based on a combination of basic science, ap- in the department of plant and soil plied research, and clinical experience gained from the com- sciences mercial equine embryo transfer program at CSU and other programs around the world. ■ The Horse: Your Guide to In the preface, McCue and Squires write, “It is our hope Equine Health Care that experienced practitioners will find useful tips in this Alexandra Beckstett, Managing Editor manual to enhance embryo collection success or post-transfer pregnancy rates. New Brian Turner, Layout and Design graduates and current students may utilize the manual to gain a basic understanding of reproductive principles as well as clinical techniques.” The Bluegrass Equine Digest is a registered Chapter topics range from a brief history to future directions of equine embryo trademark of the University of Kentucky Ag Equine Programs and Gluck Equine Research Center. The transfer. The manual contains all the information needed to set up and succeed in an Bluegrass Equine Digest is produced by the University equine embryo transfer program. The manual’s format and size allows the technician of Kentucky in partnership with TheHorse.com and or veterinarian to have it in the clinic or laboratory as a readily available reference sponsor Zoetis. It is published monthly to provide up-to-date information on equine research from guide. the University of Kentucky’s College of Agriculture, The 172-page manual was published by Teton NewMedia and can be purchased on Food and Environment. Research material is meant Amazon. to be shared. However, materials are copyrighted and require reprint permission from UK Ag Equine Programs. Past issues of the Bluegrass Equine Digest >Jenny Evans, MFA, is the interim executive director of the Gluck Equine Research Foundation and are available at www2.ca.uky.edu/equine/bed. marketing and promotion specialist senior at the Gluck Equine Research Center. 2 Bluegrass Equine Digest ❙ ca.uky.edu/equine ❙ TheHorse.com ❙ May 2015 emergent diseases are zoo- “Countries at greatest risk, Emerging Equine Diseases: notic, meaning they can be obviously, are those with a transmitted between horses significant import/export What You Should Know and people and, thus, are trade in semen as well as important to public health. live animals,” said Tim- ot long ago, we didn’t said, “horses are not exempt Such conditions include oney, and that includes the Nknow that some now- when it comes to emergent acute equine respiratory United States. So how can common equine diseases diseases.” syndrome and equine granu- we reduce the risk of a new even existed. Potomac horse locytic ehrlichiosis, Timoney disease being imported into fever, hendra virus infection, Emergent Infectious said.