Those of us with blogs involving cattle show you all these pictures of cute little calves.
How do all these cute little heifers and bulls come to be? I mean we know of “the birds and the bees”, but how does it work on most dairy farms?
For starters, we do not have a bull on our farm. First off, he doesn’t look very friendly does he?
When you start talking about using a bull to breed our ladies, he is going to need to be very large to be able to successfully breed our girls. Our cows themselves weigh between 1,200 and 1,600 pounds. Most bulls that are considered cow size, or large enough to breed a mature cow, are over 1,500 pounds. 1,500 pounds of cranky muscle and testosterone. They become very protective of their herd and can see farmers as a threat. Bulls become very aggressive and pose a safety issue that we have decided we don’t want to deal with on our farm.
Secondly, as a whole, you do not get as good of genetics with a herd bull as you could by using a bull who is at a bull stud. These bulls are from elite cow families who have been bred to other top bulls used by bull studs. They are to be the best of the best. I’m not saying you don’t get poor bulls who slip thru the cracks at studs or you don’t stumble upon an outstanding herd bull from time to time, but more often than not your better genetics come from bulls housed at a stud.
By using A.I., artificial insemination, we are also able to diversify our gene pool in our herd. Instead of having cows and heifers out of 2 or 3 bulls, we have daughters out of many bulls. This helps us vary our genes, limit inbreeding and minimize/eliminate the amount of daughters we have from inferior bulls.
Many farms still use the occasional bull. Some cows have a hard time becoming pregnant and sometimes will breed to a bull easier. Or after a cow has been bred x amount of times a farmer will put her in a bull group to hopefully become pregnant as a last chance. There are also farmers who still breed with a bull routinely for reasons of their choice. Bulls are still used on farms for varying reasons. But the fact always remains, they need to be treated with respect and can’t be trusted.
So now that we’ve covered why our farm uses A.I., how does it work?
Bulls are selected a young age to go in to stud, while at whichever stud company they live at semen is collected to be distributed to farmers. The bull mounts either a fake dummy or a steer. The semen is collected in an artificial vagina and processed in a lab.
While being processed semen is checked for quality to make sure that each dose has the possibility of fertilizing an egg. Semen is then frozen in liquid nitrogen and stored in straws. The individual straws are housed in groups of ten, called canes.
Why are the straws two different colors? The clear straw is considered conventional semen. It contains both X and Y chromosomes to give you equal possibility of a bull calf or a heifer calf. The pinkish colored straw is sexed semen. It contains 95% X chromosome semen. This gives you a much higher possibility of having a heifer calf.
While farmers want heifer calves, they don’t use sexed semen with every service. It costs more than conventional semen, it’s not as fertile and generally your superior bulls are not sexed. We use sexed semen on our virgin heifers. It helps with calving ease (heifer calves are normally a little smaller) and growing our herd, which we would like to expand.
When a cow shows signs of being in heat (mounting other cows, standing to be mounted, constant mooing, pacing) she is noted to be bred. Twelve hours after we see her standing to be mounted by other cows we pick out a bull who will correct her faults the best and breed her with A.I.
The cow is palpated and the cervix and A.I. gun are manipulated until it has passed the whole way thru the cervix. The semen is deposited in the uterus and if all goes well in 9 months…..