Boar performance : How does it change over the course of the boar’s life?
A boar is a production tool and a key factor of your business. And just like any human being, its performance will change during its life on your farm.
How does the quality of an ejaculate vary with the age of the boar? What is the influence of genetics on the volume or concentration of the ejaculate? How do you best optimize your boars?
This article will provide you with the answers to these questions.
Before entering your artificial insemination center, boars must go through a quarantine period, away from the collection center. At around six months, the average age of puberty in a boar, it is possible to start collecting semen from them. This age is variable depending on genetics. All graphs in this article come from a study presented publicly at the French Swine Research Days.
Volume : What is the influence of age on this ejaculate parameter ?
When a boar first begins to produce semen, around six months of age, the average ejaculate volume is around 220 ml as shown on this graph. It is not until the 20th month of a boar’s life when the ejaculate volume stabilizes around an average of 300 ml per ejaculate. It is around this age that the boar reaches its sexual maturity.
This volume versus age curve is variable depending on the animal’s genetics. Indeed, as shown in the attached graph, a boar with P76 genetics will tend to ejaculate a larger volume of semen compared to a Piétrain boar. This is an average over the life of a boar.
What influence does age have on the concentration of an ejaculate ?
Concerning the concentration, stability will not be reached at the same period as the volume increases. Indeed, as shown in this graph, the average concentration of an ejaculate will increase from the fifth to the tenth month. From this moment on, the concentration will stabilize over time. The first ejaculate of a boar should not exceed an average of 280 million sperm per ml. Around the 20th month, the concentration will be about 320. Thus, there is a relatively small increase in concentration between puberty and sexual maturity of the boar.Concentration will even tend to decrease slightly during the life of the boar before an unexplained peak occurs at the end of the fourth year of a boar’s life.
Like volume, concentration can also vary depending on genetics. However, the concentration differences are minuscule. However, a higher average was observed for Large White H boars.
And finally, how many spermatozoa per ejaculate ?
To summarize the two previous parts, the quantity of sperm will double over the 10 months following its first ejaculate. Indeed, at the age of 5 months for its first ejaculate, this one will contain approximately 50 billion spermatozoids. At the age of 20 months, there will be around 100 billion. At this point in its life, the boar can be said to have reached sexual maturity, and the sperm per ejaculate should remain stable over time.
These 3 parameters, volume, concentration and consequently the quantity of spermatozoa per ejaculate, will constantly change over time, reaching their maximum capacity around the 20th month of the boar’s life. It should be noted that, generally, it is the volume of semen that determines the number of spermatozoa in an ejaculate. However, during its growth, other factors can also influence the quality of an ejaculate. Indeed, sperm motility and morphology generally vary during the young age of boars.
Be patient with your animals, they are constantly changing!