Current Research Projects:
- Optimizing cryopreservation of equine semen
- Fundamental sperm membrance dynamics in relation to capacitating ability
- Welfare implications of horses used in equine-assisted therapy programs
- Discrimintation and selection by horses of different flavours in water
- A two-stage method for reducing weaning stress in horses
Optimizing cryopreservation media for stallion semen: The use of frozen semen for breeding mares is limited, mostly due to the dramatic decrease in pregnancy rates compared to fresh semen. Freezing media generally contains egg yolk to protect sperm cell membranes through the rigours of freezing and thawing, however worldwide concerns over avian influenza stress the need for development of suitable alternatives to chicken egg yolk in freezing media. Global distribution of frozen equine semen may allow unintentional dissemination of such viral threats. Additionally, glycerol has been the freezing agent most widely used, however, glycerol exerts toxic effects on the sperm cell requiring research into use of lower concentrations (2-4%). This research proposes to investigate the replacement of egg yolk with purified egg fractions and/or plant-derived soy lipids, and the interaction of these substitutes with different concentrations of glycerol. Efficacy of treatment will be determined by sperm post-thaw motility, viability, membrane integrity, and pregnancy rates in mares. This novel research will benefit the industry by providing a more suitable freezing media with increased fertilizing ability and reduced risks of microbial contamination and biosecurity threats. With more reliable protocols and a responsible proactive approach, the use of frozen semen in the equine industry can be expected to increase.
Fundamental equine sperm membrane dynamics in relation to capacitating ability: determining the physiological mechanisms regulating sperm capacitation and acrosome reaction to improve capacitation in vitro and in vivo. Intrinsic in this exploration will be characterization and understanding of sperm plasma membrane events and their downstream effects on capacitation and acrosome reaction. Of particular interest is the movement and effect of cholesterol, membrane phospholipids, proteins, and calcium and how storage conditions affect these mechanisms. The main focus is on the dynamic changes and interactions occurring in the sperm head plasma membrane; in particular the movement of cell membrane lipids, cholesterol, proteins and calcium will be tracked over the life cycle of the ejaculated sperm cell.
Preliminary evaluation of causes and contributors to injury in the equine workplace: Equine workplaces pose potential risks to employees due to the workplace environment and the unpredictable nature of horses. Although extensive literature exists on injuries occurring to riders, little research has focused on injuries occurring to employees in the equine workplace, and no research is evident on the use of health and safety programs or initiatives in equine facilities. Understanding of prevalent injuries, illnesses and health and safety issues in the equine workplace is necessary to developing health and safety programs that are practical and accessible to equine employers. Knowledge of the use and effectiveness of health and safety programs in the equine workplace will assist in application of relevant safety programs for equine workers.
Discrimination and selection by horses of different flavours in water: The sense of taste allows an animal to differentiate between various food sources and select those which are of interest. Additive flavours that will increase feed intake are of significance in instances where consumption of required nutrients is required although not preferred by the animal. For example, horses stabled in a foreign environment such as at a horse race or horse show may refuse to drink the local water due to flavour discrepancies from the home source. Dehydration is a concern particularly since these horses are losing electrolytes and fluid balance through physical exertion. Common practice in the industry is to disguise different water sources with flavours or sweeteners, however little research has been done on flavour recognition and preference in horses. This study will determine if horses recognize various flavours, what concentration of flavoured solution they prefer to drink, and if certain flavours will disguise others.
A two-stage method for reducing weaning stress in horses: The separation of a mare from its foal occurs in nature, however common equine management practices artificially impose abrupt separation methods, which have immediate negative consequences and long-term implications. Chronic and acute stress increase heart rate and stress hormones. These physiological changes increase the risk of pathological conditions, reduce learning ability, and predispose horses to behavioural dysfunctions such as cribbing and weaving, which are highly undesirable, and dramatically affect the economic value of the horse. Use of gradual weaning methods that more closely resemble the natural situation evidenced in wild horses may significantly reduce stress and have immediate short-term and potential long-term benefits. To investigate the stress levels of horses during gradual weaning, foals will be prevented from nursing using a mechanical barrier while still allowing physical contact between mare and foal. After a period of nutritional separation, foals will then be physically separated from their dams. Heart rate, behavioural observations and fecal cortisol measurements will be collected from mares and foals. Comparison of these measures with foals that are weaned abruptly will give evidence to the reduction in stress during weaning. An economic analysis of the practical costs of implementing this method in terms of equipment, labour and time costs will be performed.
Publications:
- Methods used in Ontario to Wean Foals and Determination of Breeder Perception in terms of Foal Management and Weaning. Gooding M, Merkies K, 2008. Canadian Society of Animal Science Annual Meeting/Kennedy Conference, Guelph, ON
- Stallion spermatozoa viability: comparison of flow cytometry with other methods. 2003. Merkies K, Buhr MM. in Germ Cell Protocols vol 1: Sperm and Oocyte Analysis. Schatten, H (ed). Humana Press, NJ.
- Effect of select lipids and vitamin E on motility and viability of liquid and cryopreserved boar spermatozoa. 2002. Merkies K, Bean L, Boehnke K, Buhr MM. Can J Anim Sci 83:81-88
- Assessment of stallion spermatozoa viability by flow cytometry and light microscope analysis. 2000. Merkies K, Chenier T, Plante C, Buhr MM. Therio 54:1215-1224
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