This article is written based on a research article (Link). The "iSperm® Equine portable device" mentioned in the article is the iSperm mCASA. With the iSperm, your breeding works will be much easier. Check out https://www.isperm.co/ or Contact us for the details.
What is pregnancy rate and how does semen quality affect it?
Pregnancy rate is the likelihood of pregnancy obtained after the artificial insemination is performed, that can be affected by the stallion’s ejaculate quality. The stallion’s semen quality is one of the most crucial elements, since it determines the probability of pregnancy after the artificial insemination (AI) is conducted. The semen quality, namely sperm concentration, motility, progressive motility and movement characteristics from the ejaculate serve as significant determinants of pregnancy rates, that may provide insights about the success level of the insemination and give numerous advantages during the breeding season.
How does semen analysis specifically predict the result in breeding?
Semen analysis speculate the success rate of breeding by reading the specific parameters of semen quality, such as the concentration, motility, progressive motility and movement characteristics, to be specific, the average path velocity (VAP), straight-line velocity (VSL), curvilinear velocity (VCL), straightness (STR), and linearity (LIN). These aspects from the ejaculate influence the pregnancy rate, especially the evaluation of the sperm motility and progressive motility.
The motility of the sperm authorizes us to foresee the ability of the stallion’s sperm to migrate and ovulate the eggs in the mare. In this inspection, 2 analysis methods are being used, which are linear discriminant function analysis (LDA) to see if any of the measured variables might correctly forecast the likelihood of pregnancy from a particular insemination and Receiver Operating Characteristic analysis (ROC) to verify the accuracy of the chosen semen quality criteria.
From this research, it can be recapitulated that the pre-chilled semen usually will have higher concentration and motility compared to the post-chilled semen, since extender has been added to the post-chilled semen sample. In the pre-chilled samples, the discriminant function involved STR, VSL, VAP, VCL, LIN, sperm concentration, total motility and progressive motility, where 71.7% accuracy was achieved and 0.75 in the AUC value for ROC analysis. On the other hand, the post-chilled samples was including the stallion age, STR, VCL, VAP, LIN, sperm concentration, progressive motility, and ejaculate volume as the discriminant function. Resulting in 69.6% for the overall accuracy and an AUC value of 0.83 in the ROC analysis. Where the full discriminant function equation had predicted incorrect outcome of 11 inseminations for pre-chilled semen and inaccurate prediction for 14 inseminations on the post-chilled semen.
The chilled and extended sperm (72.3 ± 6.7 × 106 sperm/mL) are expected to perform higher pregnancy rate, since the high viscosity and concentration from raw ejaculate sperm (266.7 ± 22.8 × 106 sperm/mL), will also affect the pregnancy rate due to the hindrance of the spermatozoa to swim across the cellular membrane.
Therefore, semen analysis can assist us to predict the result in breeding by knowing the concentration of the ejaculate and extend it to make the spermatozoa swim across the membrane faster and easier, thus, dilution to 100 × 106 sperm/mL or less is recommended. Discriminant function equations reflect a specific ejaculate's capacity for fertilization and forecast the likelihood of a successful pregnancy after insemination can be created by tailoring the study to specific stallions. Applying the semen analysis strategy would be tremendously advantageous for the equine breeding sector and assist in managing the reproductive performance of their stallions. In addition, highly improved result in accuracy prediction might also occur if a further specified sperm morphology analysis was conducted.
On the other hand, the pregnancy rate is not merely affected by the semen quality. There are several aspects that might affect the pregnancy rate, such as the management of the mare’s follicles, ovulation induction and the time range between semen collection and insemination.
Why iSperm is the suitable sperm analyzer?
The iSperm is able to read all of the key components of the sperm mentioned above, that are needed to be analyzed such as the concentration, motility, progressive motility and sperm kinetics rapidly and with practicality, where the sperm kinetics value can be adjusted by the user’s standard too.
Furthermore, compared to the computer-assisted sperm analysis (CASA) system, iSperm devices are definitely more cost effective and practical to be used in farms. And compared to the Receiver Operating Characteristic (ROC) analysis in this experiment, the kinetics reading from the iSperm is considerably precise as the approximate range of Area Under Curve (AUC) is high (0.8 to 0.9) either for pre-chilled or post-chilled semen.
And the microscopic camera equipped on the iSperm mCASA is readily operated in conjunction with an iPad mini, and a compact sample collection unit to enable users to perform semen analysis conveniently and efficiently, utilizing a finite sample volume, at any desired location or time.
This article is brought to you by iSperm mCASA, a mobile/mini computer-assisted semen analyzer with high accuracy and affordability for use anytime anywhere by anyone. Check out www.isperm.co or Contact us to know how helpful iSperm can be for your breeding works.
1. Medica, A. J., Lambourne, S., & Aitken, R. J. (2023, March 30). Predicting the Outcome of Equine Artificial Inseminations Using Chilled Semen. Animals 2023, 13, 1203. https://doi.org/10.3390/ani13071203
2. Horses, Horse heads, Heads image - free photo on Pixabay - Pixabay. (n.d.). https://pixabay.com/photos/horses-horse-heads-heads-stallions-1414889/