MORE and more, we are seeing the ‘blue light’ across the landscape of the Irish and UK thoroughbred breeding hubs as the Equilume Light Mask is being embraced by horse breeders.

Equilume was developed by University College Dublin researcher Dr Barbara Murphy whose research identified for the first time the optimum light level required to advance the breeding season in horses.

The horses’ natural reproductive period coincides with the light-filled days between May and September, when the environment is optimal for the survival of offspring. However, there is an industry imposed birth date of January 1st for most horse breeds born in the northern hemisphere. This creates a demand for early foals in order to produce mature yearlings and precocious two-year-old racehorses. The first problem faced by breeders is how to bring the mare’s breeding season forward to meet industry timelines.

A second and potentially more economically important problem faced by thoroughbred breeders is that of long gestation lengths. Mares that foal during the early breeding season often have far longer gestation lengths than mares foaling during the summer months.

On average, thoroughbreds have a 10-day longer pregnancy than mares foaling in the natural season. Approximately 20% of all thoroughbred mares go longer than 355 days. This fact significantly reduces reproductive efficiency on farms by creating late foaling mares each year. Often, a potential foal is lost every 3-4 years from mares that consistently go past their due dates. The correct use of lighting technology can alleviate this problem.

Utilisation of artificial light to advance the breeding season is common practice within the thoroughbred industry. Mares are often maintained indoors under barn lighting until 11pm nightly for eight to 10 weeks beginning around December 1st. The artificially extended day length acts to inhibit the hormone melatonin and fools the mare’s reproductive system into activating earlier in the year, in time for the official start of the breeding season on February 15th.

Recently, blue light has been found by researchers to facilitate more accurate and efficient levels of melatonin inhibition in other species. In 2011, Dr Murphy and her colleagues at University College Dublin investigated the threshold level of blue light required to inhibit circulating concentrations of melatonin in the horse. What they found was that very low intensities are required and that it is sufficient to deliver light to a single eye and still inhibit melatonin levels to daylight levels.

Fueled by this exciting finding, a follow-up multi-institutional study was conducted in Kentucky to determine whether low-level blue light to one eye from a head-worn light mask could advance the breeding season in mares maintained outdoors.

The Equilume Light Mask, worn by non-pregnant mares maintained outdoors on pasture, was shown to advance successfully the first ovulation of the season as effectively as standard barn lighting and in time for the February 15th official start of the breeding season.

CONSISTENT LIGHT IS KEY

But what about our pregnant mares? Significant cost is expended annually on maintaining maiden and barren mares under lights to advance the season but very few breeders then provide the same light signal to their pregnant mares. Without the light signal signifying the correct time of year for foaling, it is thought that the foal in utero does not develop at the normal rate and this leads to long gestations and often lower foal birth weights.

The key to improving efficiencies on farms is to provide a consistent annual light signal to our mares. Studies conducted using the Equilume Light Masks with pregnant mares in Kildare and Kentucky have clearly shown that mobile light therapy reduces the average gestation length by approximately 11 days, while permitting foals to develop optimally in utero and be born heavier.

An additional benefit of the Light Mask technology is early winter coat shedding, with important implications for performance horses.

The Light Mask is designed to be activated at 4pm on November 15th (northern hemisphere) and June 15th (southern hemisphere), in advance of the breeding season. It is wirelessly activated and will then automatically turn on at the same time each day and automatically switches itself off after seven hours at 11pm.

TESTIMONIAL

Ken Bolger of Redmondstown Stud, Ireland said: “We have been using the Equilume Light Masks for the last few seasons on all our barren and maiden mares and are delighted with the results. Our mares winter out and cycle early, so can be bred from the paddock with considerably reduced labour costs. This year we had a 75% first service conception rate. We will happily continue to use Equilume masks as a reproductive aid to our breeding operation at Redmondstown.”