No one wants to keep this record. Writing down that an animal died, or that it was sold because it was open, lame, or simply not good enough this year, is the least satisfying entry in any farm's books — there is no achievement in it, nothing to be proud of, and every instinct says to note it briefly and move on. That instinct is exactly backwards. A mortality or cull record is one of the few entries an outside investigator, a certifier, or an insurer will ask for by name, and it is the record most farms keep worst.
The reluctance is understandable. It is not a reason to write a thinner record than the one you'd write for a birth or a sale.
Part of the reluctance is that a mortality or cull entry rarely feels urgent the day it is made — the animal is gone, the immediate problem is handled, and whatever gets written down feels like it is only for the books. The opposite is closer to true: this is precisely the record that sits dormant for months or years and then gets pulled out, without warning, by someone asking a specific question you did not anticipate when you wrote it.
Carcass disposal is regulated by your state and locality. What disposal methods are permitted, and what has to be reported and to whom, is set by your state agriculture department, environmental authority, or local jurisdiction, and it varies. This page does not state a specific requirement or timeline — check with your state's extension office or agriculture department for what applies to your operation, and keep whatever record they require as part of the mortality entry itself.
A death and a culling decision are different records
It is tempting to file both under one heading — "animal left the herd" — but they answer different questions and should be recorded as such. A mortality is something that happened to the animal; a cull is a decision you made about it. The mortality record needs a date, and a cause where one is known or suspected. The cull record needs the decision itself: why this animal, why now — age, an open pregnancy check, a bad temperament, chronic lameness, poor weaning performance in her calves across several years. Collapsing both into "gone" loses the entire point of keeping either.
The reason is the data point, not the fact of removal
A herd that records every departure as "sold" learns nothing from a season of culling. A herd that records "sold — open at pregnancy check, second consecutive year" learns something specific and actionable: this reason, repeated, might indicate a breeding program problem rather than bad luck with individual cows. The value of a cull record is almost entirely in the reason field, and it is the field most likely to be left blank or filled in vaguely, because the sale itself feels like the complete transaction and the reason feels like paperwork after the fact.
Recorded consistently over several seasons, cull reasons become a pattern a raw headcount cannot show: a rising rate of lameness might point at footing or nutrition; a rising rate of opens might point at bull fertility or a breeding window that has drifted too long. None of that pattern is visible from "12 cows sold this year" alone.
It also matters for the animals that stay. A cull decision is, in a real sense, a selection decision made in reverse — deciding who does not continue is exactly as consequential to the herd's future as deciding who does. A record that captures why an animal left carries forward the same information a breeding decision needs, which is why a thin cull record quietly weakens the very selection pressure a herd depends on to improve.
An unexplained cluster of deaths is the record an investigator wants first
If several animals die within a short window, the first document asked for — by a veterinarian trying to diagnose a herd health problem, or by an investigator if a disease concern is raised — is the mortality log: dates, ages, which group, and any symptoms observed before death. A log kept animal by animal, even briefly, is what lets a real pattern (same age group, same pasture, same week) be seen quickly. A vague recollection that "we lost a few calves this spring" cannot be interrogated the way a dated, per-animal record can.
The record does not need to include a diagnosis to be useful — most farms are not equipped to determine cause of death on their own, and guessing at one is worse than leaving it blank. What it needs is everything that is directly observable: which animal, which group, the date, the age, and anything noticed beforehand. That much is enough for a veterinarian to start from, and it costs nothing beyond the discipline of writing it down the same day rather than a week later, once the details have already begun to blur.
Disposal is a compliance record, and it belongs with the mortality entry
How a carcass was handled — buried on-site, composted, picked up by a rendering service, or another method — is governed by your state and local authority, and it is a record worth keeping in the same entry as the death itself rather than as a separate afterthought, because the two facts (an animal died, and it was disposed of a specific way on a specific date) are usually asked about together. What that record has to contain is set by your jurisdiction, not by this page; the discipline this page argues for is keeping whatever is required attached to the mortality entry, dated, so it does not need to be reconstructed later from memory of which service was called that week.
The sale side of culling still has to respect an open withdrawal window
A cull decision that ends in a sale is still a sale, and it is subject to the same discipline covered in withdrawal and residue records: an animal culled for a reason unrelated to health can still be inside an active treatment window, and the cull decision does not override that. Farm40 applies the same rule to a cull sale as to any other — when you record a livestock sale, it checks the group for an active withdrawal window and declines to write the sale record at all if one is open. The limit is the same one stated elsewhere: this governs sales entered through it and cannot reach an animal sold on a handshake outside it. What it can do is make sure a cull decision made in a hurry does not silently skip the same check a routine sale would get.
Mortality and cull records are the least rewarding entries covered by the livestock management guide, and among the most consequential, because they are the ones an outsider is most likely to ask for by name.