Culling Females in an Angus Herd: How Selection Pressure Drives Progress

Bulls get most of the attention in breeding discussions, but the cow herd is where the long-term gains are won or lost. Every year a producer decides which females stay and which go. Those decisions, repeated over many years, determine the herd's fertility, longevity and productivity. A rate of roughly one in four females culled each year is sometimes mentioned in discussion of aggressive selection. We could not verify a source for that exact figure, so we do not treat it as a benchmark here. What follows explains how culling and replacement work, and how to think about the right rate for your own herd.

The link between culling and genetic gain

Genetic progress is a product of selection pressure and time. Selection pressure is how choosy you are: the stronger the gap between the females you keep and the herd average, the faster the herd moves. A herd that keeps nearly every female has almost no pressure on the female side. A herd that retains only the best performers and brings in replacements chosen from the best daughters has plenty.

The American Angus Association's Angus Journal profiled one producer who makes heifers prove themselves on his range before investing more in them, and another who matches females to sires using trait-by-trait data. The same article records one producer whose herd moved from 13 percent Prime in 2012 to a range of 50 to 75 percent Prime now (Angus Journal). Those results reflect that operation's own management and goals, and they will not translate directly to another herd, but they illustrate how consistent selection compounds.

The culling rate is a result, not a target

A common mistake is to pick a percentage and cull to hit it. A better approach is to establish criteria and let the rate follow. Rates differ with herd size, age structure, market conditions and how fertile the herd is. A younger herd with strong fertility may cull less because few cows fail. A herd with problems may cull heavily and still need to cull more.

The cost side matters too. Replacement heifers are expensive to raise, and they do not earn income until they wean a calf. Culling too hard is costly, while culling too lightly keeps unproductive cows on the feed bill. The right balance depends on what your replacements cost, what cull cows bring and how much genetic gain is worth to you, so budget it. Our cow-calf budget basics guide shows what a cow costs to keep.

Criteria that make sense

Reproduction

Open cows at preg-check are an obvious cull. So are cows that calve late in the season repeatedly, since they delay the whole herd's calving window. Fertility leads every list because a cow that does not raise a calf has no value.

Calf performance

Compare weaning weights within the herd, adjusted for age of calf and age of dam. A cow whose calves are consistently at the bottom of their group is a candidate to leave.

Structure and udder

Poor feet and legs, bad udders and teats that calves cannot nurse are heritable or otherwise cost production. They are a cull whether or not the cow is bred.

Temperament

Aggressive or flighty cows endanger people and tend to pass the tendency on. Most producers cull on temperament without hesitation.

Health and longevity

Chronic problems like prolapse, repeated mastitis or repeated calving trouble signal a cow that costs more than she returns.

Choosing replacements

Culling opens a slot, and the replacement fills it. If you retain heifers, keep those from the best, most fertile cows, sired by bulls chosen for your goals, and show good growth and structure. Genomic testing can help rank heifer calves, particularly when you have more than you need (see our guide to what a genomic test adds). Our guide to choosing replacement heifers goes through the selection steps in more detail.

Records make it fair

Culling on memory is how good cows get sold and bad ones stay. Individual identification and a simple record of calving date, calf weaning weight, preg-check result, and any treatments or problems let you cull on facts. Review the cow list at weaning and again at preg-check. The University of Nebraska beef program and the Beef Research site offer record-keeping resources.

Markets and timing

Cull cow prices fluctuate, and when cattle supplies are tight, replacement heifers cost more. Both change the economics of culling, so look at current USDA market reports before deciding. The USDA Economic Research Service publishes analysis at ers.usda.gov. When replacements are costly, it can make sense to slow culling of marginal cows, while being firm on the clearly poor ones.

What buyers should know

Consumers benefit when herds select for fertility and carcass quality, because it supports a steady supply of beef at stable quality. Programs like Certified Angus Beef recognize carcass merit at the packing plant, but the genetics behind it were built female by female. For more on how herd decisions fit together, see farm.fm's page on financial planning for Angus producers, and use the agriculture directory to find extension and veterinary help.

Prices and recommendations change, so confirm current numbers with your extension specialist or veterinarian. This site is independent and not affiliated with the American Angus Association or Certified Angus Beef.