|The Effect of Feeding FoalMaker™ on Semen Quality and Fertility in Breeding Stallions|
Materials and Methods
All mares were bred by artificial insemination, therefore effects on conception rates were not due to changes in total sperm per ejaculate. Only mares bred on farm using fresh semen and whose 16 day pregnancy status confirmation was preformed on farm were used. These selection criteria resulted in a higher proportion of “problem mares” which explains the below normal conception rates for both the control and treatment groups.
Fertility data was analyzed using a mixed model ANOVA procedure (PROC Mixed) with repeated measures. The model consisted of a dependent variable percent pregnant and independent class variables treatment, year and time period (1-5). Stallion was included in the model as a random factor. Semen quality data was analyzed using PROC GLM with repeated measures.
2001 season. Arrow indicates time that treatment and placebo were started. WK16-20 data points represent fewer than all stallions.
Conflicting anecdotal information painted a confused picture of the effect some ingredients may have on semen quality and prompted this investigation. Benefit derived from the supplement was not reflected in routine semen analyses as quality did not differ during a 20 week evaluation period between treated and control stallions. Most importantly there was no detectable decrease in quality observed.
We acknowledge the limitations of this type of study. The limited number of stallions in the control group decreases our ability to distinguish pregnancy rates among treated and control groups. Time period T5 was eliminated from some of the analyses due to the fact that it was the end of the breeding season and several stallions had few or no observations during this period. Although no specific procedures were implemented to assure the mares bred to each of the treatment groups were similar, randomization of stallions is assumed to satisfy this assumption. It was not possible within the scope of this study to define a mechanism for the improved fertility observed. Neither was identifying which ingredient or combination of ingredients affected the change. However it was a starting point. Logically it would seem there was a positive impact of the supplement on sperm development and/or function that was not detected by routine methods of semen analysis. Pursuant to this need a follow up study is underway to further define the effect of the supplement on fertility and semen quality.
The study cited above was designed by and the sample and data analysis done by a board certified theriogenologist and equine practitioner at a Veterinary Teaching Hospital. The data is being collected at a commercial breeding facility using 11 of their stallions and is supervised by their resident veterinarian. Only cycles bred on farm with corresponding on farm pregnancy examinations were used for the per cycle conception rate data [1,437 cycles over years one and two]. This selection criteria yielded a mare population that contained more problem breeders than the general population serviced by these stallions. No changes were made to the way any mares were handled at the facility. All mares were bred AI with a dose of semen that was controlled for the amount of sperm delivered. Therefore, the observed increase in total sperm and the increase in conception rate are independent effects.
| Supplementation with FoalMaker™ should begin 60 days prior to the
breeding season to support all stages of the spermatogenic cycle.
|Research Information © 1997 - 2005 MD's Choice, Inc. and respective holders.
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