With fall preg-checking season well underway, some herd owners are surely pleased with their results. Meanwhile, others are looking for bred females to purchase.

The goal shouldn't be to have 100% of your cows bred each year. Herds at or near 100% pregnant year after year generally represent one of two situations -- a very extended calving season or overfeeding. Neither option is cost-effective for overall herd profitability.

Financial analysis indicates a pregnancy percentage of 90-95% in 65 days is both achievable and likely most profitable. If your herd is below this level, some investigation by you and your herd-health veterinarian is needed.

When I investigate a reproductive problem, I break it into the following categories: For bull problems, it's Breeding Soundness Exam (BSE), overuse, or lack of libido. For cow problems, I look at nutrition, environment, disease and genetics.

Bull problems. When a large percentage of cows are open, my first thought is generally a bull problem. With a national annual average of about 10% of bulls failing their BSE, an annual BSE on every bull before turnout is a must. Nearly every year I've been in practice, I've seen a group of cows all open due to a sterile bull. It's an easy situation to figure out.

Another bull problem is simply overuse. My rule of thumb for Midwest herds is you need a month of bull age for every cow in a 65-day breeding season. If you have 100 cows in a group, you need "100 months of bull" to breed them.

This means three bulls at three years of age, or two bulls at four years of age, would be adequate bull power. We know some bulls can service more than 50 cows in a breeding season, but 50 cows to a bull is our upper limit.

We also know using bulls of greatly differing ages doesn't work well. Having a yearling bull in the pasture with a three- and four-year-old adds up to 100 months, but the yearling will likely get no cows bred due to dominance issues by the older bulls.

The final bull problem is lack of libido. These bulls generally get some cows bred but not enough. To diagnose this problem, place a group of open cows with the bull(s) in question. If the bull lies down in the shade when a cow is in heat, he's asking to leave the herd.