Animal health matters: It's always a good year to buy bull insurance

Russ Daly Special to the Farm Forum
Farm Forum

Even though I’m staring out the window at the aftermath of a mid-March snowstorm, I’m ready to call winter done.

I think most cow-calf producers are pretty OK with this past winter; we’ve certainly had longer, colder, snowier ones. This might tempt some producers to consider their bulls — presumably good and fertile at the end of last breeding season —are good to go for the upcoming breeding season as well.

That’s usually a fair bet. But how do you know for sure? The only way to ensure bulls’ fertility prior to this breeding season is to insure them with a breeding soundness exam (BSE).

Some years — especially ones with prolonged, bitter winter cold snaps — are more concerning than others regarding how our bulls wintered. We might even notice frostbite or skin damage on the bulls’ scrotums after such bad winters. Veterinarians tend to get a lot more interest in BSEs after such winters.

But some of the worst bull-testing seasons I’ve been through have occurred after comparatively mild winters like the one we just went through. It’s hard to say why; maybe we subconsciously slack off on bedding, wind protection and nutrition when the temperatures are in the 20s instead of the -20s. My point is that breeding soundness insurance should be an annual appointment for every bull, not a sporadic decision made year-to-year.

The insurance I’m talking about isn’t the policy insuring your bull against accidental death or infertility. Those policies only pay back what you paid for the animal. Herd-level losses due to an infertile or subfertile bull will run much deeper.

Reproduction drives the profitability of the cow-calf enterprise, and there’s no more important animal to a bull-bred herd than the bull himself. Assuming a bull is good, just because we can’t see anything wrong, is a bad idea. While completely sterile bulls are uncommon, one out of five bulls is subfertile on average and thus incapable of breeding his share of cows during the season.

A proper BSE has three components. First, the veterinarian measures the bull’s scrotal circumference. This directly measures the bull’s serving capacity, or how many cows he can handle. On the BSE scoresheet, this is a “pass-fail” test. The bull must exceed a minimum circumference — 30 centimeters for a young bull and up to 34 centimeters for two-year-olds and those that are older. This is a low bar to clear; most bulls will measure much larger.

Next, a semen sample is obtained and examined under the microscope. The veterinarian judges the sample’s motility, or how well individual sperm cells move. The pass-fail threshold is 30% progressively motile sperm.

The next part of the BSE is important — assessing the morphology, or structure, of the sperm cells. Individual cells are stained and examined for abnormalities under the microscope. To pass, a bull needs at least 70% normal sperm cells. Hot conditions, stresses due to injury or illness, or bull immaturity can cause defective sperm cells that won’t be able to fertilize an egg. Morphology analysis is sometimes skipped by lay examiners. This is unfortunate and unacceptable: poor morphology is the reason for as many as 50% of BSE bull failures.

A good BSE will also include a thorough evaluation of the whole animal: the feet, legs, eyes, and internal and external reproductive organs.

The best time for a BSE is 30 to 60 days prior to the breeding season, allowing for evaluation close to turnout but also for time to arrange retesting or a replacement if needed. Some bulls will be classified as “decision deferred,” meaning he doesn’t pass the BSE today, but has a good chance of passing later, given time. Yearling bulls often fall into this category. Studies show that only about 35% of 12-month-old bulls produce BSE-satisfactory semen. While most will improve with a little more age, it isn’t a given, so a full retest is necessary 3 to 4 weeks later.

In addition, a BSE only measures the bull on the day he’s tested. It doesn’t assure that a passing-grade bull won’t encounter problems like injuries or pinkeye after he’s turned out to pasture. Producers should build in time to observe bulls once they’re on the job, and quickly respond to problems when identified.

Cow-calf herds simply have too much at stake to not test every bull that goes out to pasture, every year. Breeding soundness exams are insurance policies one shouldn’t live without.