Pregnancy testing beef cows at weaning enables producers to strategically manage the herd. Not only does it allow producers to cull cows that will not produce a calf the following calving season, but pregnancy testing also allows producers to sort cows based on their expected calving date.
Because of the extensive rangelands in the Southwest, it is not uncommon for cattle to be gathered only twice a year—at weaning and branding. If we consider a typical 200-head spring-calving operation that weans calves in October and brands calves in May, we can assume about seven or eight months between weaning and branding. During this time of the year, we would expect open cows to eat around 20 pounds of forage a day. Additionally, based on the information we have in the Standardized Performance Analysis (SPA) database, we can expect fall pregnancy rates to be around 85 to 90 percent, and supplemental feed costs of $60 per head. Let's also assume that of the $60 annual purchased feed cost, 90% (or $54) is fed between weaning and branding and that pregnancy testing costs $2 per cow (veterinary travel included).
Therefore, pregnancy testing the entire herd of 200 cows cost about $400, and about 20 cows are open (90% pregnant). If the 20 open cows are sold at weaning, there is a savings in feed costs of $54 per open cow culled. In other words, $1,080 is not spent supplementing cows that are not pregnant, and there is a reduction in total forage consumed by the cow herd. We can estimate the forage saved by not grazing the 20 open cows to be about 20 pounds per cow per day for 225 days (weaning to branding), which is 2.25 tons per open cow (a total of 45 tons). So, for $400 and the additional cost of labor necessary to pregnancy test, $1,080 or more is saved in feed costs, and 45 tons of forage is left on the range. In this example, the cost of pregnancy testing would be covered if only four of the 200 cows were diagnosed as open and culled. For operations that consistently have 10 percent or more dry cows at branding, the return on the investment of pregnancy testing is much greater.
If you question the economics of pregnancy testing and if you as a producer determine that dollars are not available to pregnancy test all cows, it is worthwhile to pregnancy check young females. Nonpregnant heifers can be managed into a different system and likely be finished before they reach B bone maturity. In addition, the group of females that have the greatest nonpregnant rate are cows trying to get pregnant for the second time.
