“If there is a high risk that continuing to raise a replacement heifer is going to result in a poor milking animal, it may be prudent to cull that heifer or calf at the time the risk becomes evident,” says Pat Hoffman, dairy scientist and heifer management specialist at the University of Wisconsin-Madison. Here is his advice:
• Freemartin heifers are obvious targets for culling. Very few will develop a functional reproductive tract.
• Calves or heifers with severe pneumonia grow slower, breed and calve later, and produce less milk than their healthy herdmates.
• Calf scours, on the other hand, has not been linked to impaired adult productivity, and should not be a consideration for culling.
• As groups of heifers mature, the unthrifty, “slow growers” should be evaluated for possible culling, particularly if their impaired growth is due to a condition that is difficult to remedy, such as PI BVD, chronic navel infection, inbreeding, abortion or founder.
• If genomic information is available at an early age, culling heifers for low net merit or negative predicted transmitting ability for milk yield also is an option.