Dr. Roy Lewis DVM, Special to T&C
Winter and cold weather don’t make for great semen evaluation.
This winter has been great so far except for one deep freeze but cold weather at the wrong time can really raise havoc with semen evaluating plans. Semen results on young bulls and herd sires may not be all that desirable to start with. As a result, we may see more bulls deferred especially because of semen defects in winter. Don’t panic and work with your veterinarian as they can best advise what the final outcome might be and even give a rough idea of when the bulls could potentially see their semen scores rise if there has been an extended period of stress from really cold weather.
The extremely cold weather causes from anything inactivity in the bulls and stagnant semen to issues with cold shock to the sperm. Both these things can cause sperm abnormalities and a failing semen score. Defects like bent tails, DMR’s, detached heads and other defects. The bull may be tried right there again a second time to see if any improvement. Mature bulls are even tried a third time right then and there.
Some veterinarians are doing a real good thing in the cold weather knowing tests may be iffy at best. They are going through and measuring the bulls at least palpating both the testicles and palpating the internal sex glands such as the seminal vesicles for any signs of enlargement scarring etc. They then lightly ejaculate the bulls to get protrusion of the penis so they can be pro-active checking for warts, cuts, hair rings or ligamentous tie backs (persistent frenulum’s) on the penis. Persistent frenulums are an interesting phenomenon. They are heritable and there is no female counterpart. Commercial cattlemen then have no issue to buy a bull that has had a frenulum as all male offspring become steers. Purebred breeders on the other hand want to avoid using one as a herd sire as incidence in his purebred bull calf offspring will go up. The best example I can use was a small angus purebred breeder had three out of eight bulls with persistent frenulum’s an extremely high number whereas on average I might see one every 100 bulls or so. If any pus (white blood cells) in the semen the bull is potentially treated with anti-microbials. Checking all these things goes a long way to ensure when the bulls are breeding soundness examined later that they are much more likely to pass with no unexpected problems. The beauty of this system is the actual test day then becomes a recheck day as well on these other problems.
We can test bulls in pretty cold weather but we must have heat to look after the microscope the veterinarian and the semen sample. We need to be careful to not ‘coldshock’ the sample as this may lead to bent tails which are caused by the cold shock itself and not the fault of the bull. You as a producer must realize that many of these so-called rusty loads are just that and the bulls simply need to be redone. If the bulls can be naturally stimulated by having cycling cows or heifers even if cull ones nearby that will help ensure they have fresh semen to examine and it will be a truer test of their real fertility.
Frostbite is always hard to assess as the bulls can pull up their testicles and even though the scrotal skin may be scarred and sloughing off you don’t know until you test as to the degree of damage to the formation and maturation of the sperm. Also, damage may be reversible and of course there is lots of inflammation with the scab sloughing off. Other bulls have lots of tag on them and if tag freezes onto the testicles that can also lead to frostbite. Other bulls even though lots of bedding stand backed into the wind and experience huge wind-chill. Again, each case needs to be assessed on its own merits.
All purebred breeders should also test their main herd bulls as they are often assumed to be OK, but one never knows. Also, purebred breeders at least initially run with single sire mating’s so if the one bull is infertile can have disastrous consequences to their breeding program. Commercial breeders commonly test every bull every year. Even if a bull has two breeding seasons yearly it is wise to test just before each breeding season as you never know what may have happened over the winter or between the two breeding seasons. I am sure many of you advise your commercial customers of the great benefits of semen evaluating. I am always amazed as to how consistent veterinarian to veterinarian we are in this procedure.
We can find bulls with one testicle severely damaged but from an ability to breed and get cows pregnant standpoint they may still be fertile (good semen coming from the one undamaged testicle) and are good to perhaps keep as a spare even. The breeding capacity may be reduced somewhat as only one testicle is functioning but still can be a functional bull. Your veterinarian would be best to advise as the future use for your bulls. Again, most veterinarians will advise giving the necessary vaccines to the bulls and possibly treating for internal and external parasites. Let’s hope semen evaluating goes well for you this spring and there are no unexpected surprises. There are newer and newer technology making the procedure of electroejaculation much smoother. There is way less vocalization, going down and the amount or success of the collection is improved.
Most purebred breeders semen collection and evaluation is a very big day and lots rides on it. Pick the appropriate day and make sure you have adequate help and that the veterinarian can set up his microscope in a warm location. Restraint will depend on the veterinarian as I like to keep the heads free in the chute and find less will go down as well. Happy Semen Evaluating this spring everyone and I hope all the bull sales go as well as last year. There are lots of variables with every semen evaluation day from age of the bull. If you get no sample and all other things seem fine it may just be he ejaculated on the way to the chute and you simple have an empty tank of semen. Patience and tincture of time goes a long ways when it comes to semen evaluation day.
Editor’s Note: Roy Lewis was a practicing vet in Westlock for 30 years, has worked at Farmfair International and does consulting work in the cattle industry via his company Roy Lewis Veterinary Services.