Blue light from individual light masks directed at a single eye advances the breeding season in mares.

The research article centers on exploring whether low-intensity blue light directed at a single eye can effectively advance the breeding season in mares. The article highlights that the blue light technique can be an effective alternative to indoor maintenance for advancing breeding, with potential economic and welfare benefits for horse breeders and horses respectively.

Research Objective

The primary objective of the research was to investigate whether low-intensity blue light from light masks could effectively speed up the breeding season in mares. The blue light, projected from masks and aimed towards a single eye, was expected to inhibit the production of melatonin. Melatonin is known to play a key role for seasonally breeding animals, acting as a decoder of photoperiod.

Methodology

An unfamiliar technique was used in this experiment where:

• The researchers selected 59 non-pregnant, healthy Thoroughbred mares from Kentucky horse farms for their study. The data collection period lasted from November 20, 2011, to February 10, 2012.
• The mares were divided into three groups. Group 1 consisted of 16 mares kept under barn lights until 23:00 daily. Group 2, composed of 25 mares, wore light masks that were programmed to turn on between 16:30 and 23:00 daily and the mares were kept outdoors. The remaining 19 mares, or Group 3, stayed outdoors while subject to natural light. This group acted as the control group.
• All the mares underwent rectal ultrasound examinations at intervals of two weeks and samples of their blood were collected for progesterone analysis.
• The mares were considered to have reached oestrous cyclicity, or the ability to go into heat and subsequently breed, if they had follicles larger than 20mm along with serum progesterone greater than 1ng/ml as confirmed by the ultrasound examination.

Research Outcome

The result of this experiment shows that:

• By February 10, a large majority of mares in Groups 1 and 2 were exhibiting oestrous cyclicity, at 87.5% and 80% respectively. In contrast, only 21% of mares in Group 3, the control group, were in this phase.
• A comparative study between the groups showed no significant difference between Groups 1 and 2. However, there was a significant distinction between Groups 1 and 3, and Groups 2 and 3.

Conclusions

From the experiment, it was concluded that using low-intensity blue light directed at a single eye from a light mask is effective in advancing the breeding season in mares. This technique was not only comparable to the commonly used method of keeping mares under barn lights but also suggested economic savings for breeders who could cut down costs associated with maintaining mares indoors. It also indicated potential welfare benefits for horses as they can be kept outdoors.