Pregnancy Diagnosis in Cows and Buffaloes: Progesterone and PSPB

A blood test can help check whether a cow or buffalo is pregnant by measuring progesterone, a hormone, or PSPB, a protein made by the placenta. Both tests use serum, the clear liquid that separates from clotted blood, and a registered veterinarian reads the result together with the breeding date and the animal's history.

Why check pregnancy early?

A cow carries her calf for about nine months, and a buffalo for about ten. An animal that is not pregnant, but is thought to be, can lose weeks or months before the next chance to breed. If an animal keeps failing to conceive, an early answer lets your vet look for the reason sooner.

Watching for heat is not a reliable check. Heat signs in buffaloes can be weak or easy to miss, and some pregnant animals still show signs of heat. A test can help your vet know sooner.

Palpation (a hand check through the rectum) and ultrasound by a vet are still the usual ways to check pregnancy on the farm. They let the vet feel or see the calf. Blood tests are an extra tool. They are useful when you want an early answer or when a vet is not close by.

Keep a calendar of heat dates and breeding dates for every animal. It makes any test result much easier to read.

How the progesterone test works

Progesterone is a hormone made by a small gland on the ovary (the corpus luteum) after an egg is released. It stays high if the animal is pregnant, and it falls if she is not.

At about three weeks after breeding:

• a low level suggests the animal is not pregnant
• a high level may indicate pregnancy, but it is not proof, because other things can keep the level high

So progesterone is better at showing that an animal is not pregnant than that she is. Vets also use it to understand breeding problems, for example when no heat is seen. The lab does this test on serum: see Progesterone, Serum.

How the PSPB test works

PSPB stands for pregnancy-specific protein B. The placenta, the tissue that links the calf to its mother, makes it. Once a pregnancy is established, PSPB appears in the mother's blood.

• In cows it is usually used from about four weeks after breeding. The earliest reliable day can differ between species and test kits, so ask the lab when you book.
• PSPB from an earlier pregnancy can stay in the blood for some weeks after calving. Testing too soon after a calving can give a misleading result. Tell the lab the calving date.
• A positive result may indicate pregnancy. A negative result at the right time may indicate that the animal is not pregnant.

Taking the sample

Good records make the result easier to read. A simple timeline looks like this:

• Day of breeding: write down the date of artificial insemination (AI) or natural mating, and also the last calving date.
• About three weeks later: a progesterone sample can help show animals that are not pregnant.
• About four weeks later or more: a PSPB sample can be used in cows.
• Later: your vet can check by palpation or ultrasound and look at the calf.

To take the sample:

• Blood is collected by your vet or a trained person. It is left to clot, and the clear serum is separated.
• Keep the sample cool and send it soon. Do not freeze whole blood.
• Label it with the animal's name or tag number and the dates.

The Pregnancy Diagnosis for Cow & Buffalo (Progesterone / PSPB) uses serum. The lab confirms whether it uses a progesterone test, a PSPB test or both when you book. Reporting time is confirmed then too. In Bhopal, sample collection at your door is free, and the steps are in Free Home Sample Collection in Bhopal: How It Works.

What the result can and cannot tell

A blood test shows the hormone or protein level at that moment. It does not tell the age of the calf, whether the calf is healthy, or whether the pregnancy will go to term. Some pregnancies are lost later, so if an animal that tested pregnant comes back in heat, aborts or looks unwell, tell your vet.

Wrong timing can make a result confusing. Your vet may repeat the test later, or check with palpation or ultrasound. If a result suggests that the animal is not pregnant, your vet may plan the next breeding or look for a breeding problem.

The Breeding & Pregnancy Pack brings pregnancy diagnosis, progesterone and brucellosis together. Brucellosis is an important cause of abortion, and you can read about it in Brucellosis in Cattle and Buffalo: Why Herd Testing Matters.

When to talk to your vet

Talk to your vet if:

• an animal shows no heat, or keeps coming back in heat after breeding
• there is a discharge, a swelling or an abortion
• a pregnant animal looks unwell
• you plan to make decisions on feeding, milking or selling based on a result

A registered veterinarian interprets pregnancy test results together with the breeding record and the animal's signs and history.