view - Department of Reproduction, Obstetrics and Herd Health
view - Department of Reproduction, Obstetrics and Herd Health
view - Department of Reproduction, Obstetrics and Herd Health
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
1.1.1. Introduction<br />
CHAPTER 1.1<br />
The widespread increased use <strong>of</strong> artificial insemination (AI) in domestic animal reproduction<br />
implies a growing awareness concerning the male’s fertilizing potential. Indeed, the fertility <strong>of</strong> one<br />
individual male can have an enormous impact on the pregnancy outcome <strong>of</strong> hundreds <strong>of</strong> females. As<br />
such, the economic importance <strong>of</strong> male fertility in breeding animals has increased proportionally.<br />
Focusing on livestock, the financial interests are equally important for business both for<br />
owners <strong>of</strong> male <strong>and</strong> female breeding animals. For the male side, more insemination doses represent<br />
a higher income for the breeder or AI company, but the downside can be that lowering the dose<br />
might result in a decreased conception rate (Chenoweth et al., 2010). This will affect the production<br />
results <strong>and</strong> might lead to law suits against the AI companies that are involved. International<br />
guidelines on the minimal quality requirements for an AI dose would protect the owners <strong>of</strong> the<br />
female animals but could also provide insurance for the male counterpart. However, before those<br />
uniform international guidelines for different animal species can be established, a consensus is<br />
required on techniques <strong>and</strong> settings used for semen analysis. After all, methodology <strong>of</strong> analysis has a<br />
major influence on the outcome parameters.<br />
In many aspects the equine breeding industry is comparable with the production animal<br />
breeding industry, although there are some striking differences. In the latter, the importance <strong>of</strong> a<br />
given positive trait (e.g. faster growing rate, higher milk production) might be less attractive for<br />
selection when associated with markedly decreased fertility. This is in sharp contrast with equine<br />
breeding, where selection is most <strong>of</strong>ten based on breed characteristics such as phenotype or sports<br />
performance. Consequently, a possible reduced fertility outcome becomes only important in the long<br />
run. Additionally, a superior performing stallion with decreased fertility might even be more<br />
attractive to breeders <strong>of</strong> sport horses, as breeding with this stallion will not only lead to <strong>of</strong>fspring<br />
with a high performance expectation, but due to its subfertility it will also result in a low number <strong>of</strong><br />
foals. The game <strong>of</strong> supply <strong>and</strong> dem<strong>and</strong> will thus increase the value <strong>of</strong> the <strong>of</strong>fspring even more.<br />
Due to great dem<strong>and</strong>s <strong>of</strong> AI doses from famous, popular stallions, normal fertile stallions<br />
might seem subfertile. At a given time a (too) popular stallion might breed more mares than there is<br />
semen available, which will very <strong>of</strong>ten result in more AI doses containing lower numbers <strong>of</strong> sperm.<br />
Eventually, this might lead to a decreased conception rate <strong>and</strong> increased costs for the mare owners.<br />
Therefore, regardless <strong>of</strong> the intrinsic fertility <strong>of</strong> a stallion, minimum requirements for an AI dose<br />
concerning number <strong>and</strong> quality <strong>of</strong> the sperm might provide an assurance for the breeders.<br />
7