Pregnancy Toxemia in Beef Cows

Pregnancy toxemia is an energy shortfall that hits cows late in gestation, often when feed is short or weather turns bad. It can be fatal, so the focus is on spotting risk early and working with your vet and nutritionist.

Key points

Pregnancy toxemia comes from an energy shortfall in late gestation.
Thin, over-conditioned and stressed cows are at greater risk.
Test forage and plan the late-gestation diet with a nutritionist.
Make sure every cow actually gets to eat, and keep water open.
Call the veterinarian early for any off-feed or down cow.

What is going on inside the cow

In the last stretch before calving, the growing calf takes a large share of the cow's energy. If the cow cannot eat enough to meet that demand, her body breaks down fat to make up the difference. When that goes too far, byproducts build up in the blood and the cow becomes sick. That is pregnancy toxemia, sometimes called ketosis of late pregnancy.

It is better known in sheep, but it occurs in beef cows too, particularly when feed quality, quantity or access drops in late gestation.

Cows most at risk

Think about any cow that cannot eat what she needs. Thin cows with little reserve are vulnerable, and so are very fat cows, which can lose appetite near calving. Cows carrying a large calf or more than one calf, cows bullied away from the feed, and cows lame or sick with something else all deserve a closer look.

Sudden stress also matters. A blizzard, a long wet spell, a water source that freezes, or a hay supply that runs out can push a marginal cow over the edge.

Signs to watch

Early signs are subtle and easy to blame on the weather. A cow that hangs back at the feeder, seems dull or drifts away from the herd may be starting to slide. As the problem worsens, she can become weak, wobbly and eventually down.

Because several other late-pregnancy problems look similar, a veterinarian needs to sort out the cause. Do not assume you know it from the outside.

Reduced appetite or leaving feed untouched
Dull attitude, standing apart from the herd
Unsteady walk or trouble getting up
Cow down in late pregnancy with no clear injury
A sweet or unusual smell on the breath, which your vet may mention

Prevention starts with feeding and condition

The best prevention is a well-planned late-gestation diet matched to the cow's body condition. Beef body condition scoring uses a 1 to 9 scale, and your vet or extension specialist can tell you what range suits cows heading into the last trimester. The goal is to avoid cows that are too thin or too fat, rather than trying to fix it in the last few weeks.

Test your forage. Hay that looks fine can be low in energy or protein, and only a lab test tells you. A nutritionist can then build a plan using what you have.

Management steps that help

Make sure every cow can eat. Give timid cows and young cows a separate group so they are not pushed off the feed, and provide enough bunk or feeding space for the number of animals. Keep water open and clean in cold weather.

Plan for storms before they arrive. Having extra feed stored and a way to get to cattle in bad weather prevents the kind of missed meals that start the problem.

Sort cows by condition and age if you can
Provide enough feeding space so shy cows eat
Keep water thawed and accessible
Check late-gestation cows daily in bad weather
Keep a hay reserve for emergencies

If you suspect a case

Call your veterinarian promptly. Treatment must be directed by the vet, and the sooner the cow is seen, the better her chances. Do not try to force-feed or drench a weak cow, because she can inhale it.

Ask the vet to look at the whole group and not only the one cow. If one cow is affected, others may be close, and the feed plan may need to change right away. Any withdrawal times from treatment must be followed exactly.

Common mistakes

Waiting until calving to feed better is the classic mistake, because the damage is done before the calf is born. Others include skipping forage tests, letting bossy cows monopolize feed, and ignoring a cow that is simply off her feed. Treat a missed meal in a late-pregnant cow as a warning sign.

When to get help: Ask your veterinarian to evaluate any late-pregnant cow that is off feed, dull or down, and ask a nutritionist to build a late-gestation ration from a forage test. Follow all label or vet-set withdrawal times for treated animals.

Sources and further reading

Organization homepages are linked so you can search them for current guidance on this topic.

More in Herd Health & Cattle Care

← Milk Fever in Beef Cows Acidosis in Feedlot-Bound Calves →