Mark Johnson, Oklahoma State University Extension Beef Cattle Breeding Specialist, offers herd health advice as part of the weekly series known as the “Cow Calf Corner,” published electronically by Dr. Derrell Peel, Johnson, and Paul Beck. Today, Johnson discusses the value proposition of bulls.
Breeding season is approaching and bull turnout is only weeks away for herds that plan to start calving next January. We are fortunate in Oklahoma to have a large number of outstanding registered seedstock breeders who are, and will be, marketing bulls in volume in our state. The opportunity to invest in genetics to improve the profit potential of your operation leads to several questions and requires planning.
The first goal of breeding season is to get cows bred early in breeding season, resulting in more calves born earlier in calving season, shorter breeding/calving seasons, older calves at weaning, and ultimately, more pay weight at weaning due to calf age. The typical beef calf gains about 2 lbs./day up until weaning; accordingly a calf born one heat cycle (21 days) earlier will wean off about 40 lbs. heavier. How do we get this accomplished? By having an adequate amount of bulls to get cows serviced. The following shows a conservative expectation of the number of cows we should expect bulls to cover in a defined breeding season.
12 – 15 month old bulls = 10 – 12 females
15 – 18 month old bulls = 12 – 18 females
18 – 24 month old females = 18 – 25 females
24 mo. & older = 25 – 35 females
2 – 6 year old bulls = 25 – 35 females
Rule of Thumb: One female per month of age at turnout (after passing yearling Breeding Soundness Exam)
For example: If I have 60 heifers to breed and plan to turn out 15-month-old bulls, I will need four bulls.
What is the typical life expectancy of a breeding bull? Typically up to the age of 6 is “prime of life” for breeding bulls. This isn’t to say that all bulls will break down at this age, but is more likely to happen after age six. Often when an older bull goes bad, it isn’t discovered until after breeding season when we are doing pregnancy checks.
