Shropshire Star

Cow pregnancy and the milk test

An effective reproductive management program is key to maximising long-term profitability at the dairy farm.

Published
Bernadette Crayston is the Cattle Information Service manager for Shropshire, Midlands.

Extended calving intervals can quickly lead to lower overall production and higher culling rates due to reproductive issues, which is why it is important to identify non-pregnant cows as swiftly and accurately as possible. Adding a milk-based pregnancy test to the pregnancy checking protocol may be the tool to do just that.

Although reproductive technologies and management practices have improved reproductive performance in recent years, there are many challenges that can disrupt a good breeding program. High levels of early embryonic death can lead to higher than anticipated numbers of open cows in late lactation if they are not re-checked following early pregnancy diagnosis.

Producers wish to determine as quickly as possible if a breeding resulted in a pregnancy. With current technologies, many producers determine initial pregnancy as early as 28 days. The question then becomes how many of these cows maintain their pregnancy past the 28-day gestation window?

Losing a pregnancy later in gestation has a significant economic impact. While the risk for a pregnancy loss decreases throughout gestation, the economic loss increases. The question becomes: How quickly can one determine a cow is not in calf?

Assuming initial pregnancy determination occurs at approximately 28 days in gestation, and setting up a protocol performing a follow-up pregnancy check at around 65 to 75 days in gestation, would catch most pregnancy losses. A late-lactation pregnancy check prior to dry-off at 180 to 210 days in gestation would catch any late losses.

With the introduction of milk pregnancy testing, a new convenient method is now available to producers and veterinarians to check for initial pregnancies and/or follow up confirmatory tests on the milking herd.

The milk pregnancy test can be run using preserved milk samples collected on milk recording day, or the producer can strip cows and collect a small amount of milk and send this to the laboratory who conduct the milk pregnancy test.

In most cases, the laboratory can return results within one business day from when it received the milk sample. The milk pregnancy test can be run from 60 days post-calving and as early as 28 days post-breeding. Depending on volume, the cost is £3.50 per sample, with re-checks being free.

To use the milk pregnancy test, it is key that the producer, in consultation with the veterinarian, establishes a protocol that best suits the individual farm’s needs. An initial determination of pregnancy by the veterinarian with follow-up testing using a DHI milk sample is a very cost-effective option.

The Cattle Information Service offers a range of services providing data to make informed decisions about current and future herd performance. It operates a state of the art laboratory in Telford that processes milk samples from 50 per cent of the dairy cows in the UK.

Bernadette Crayston is the Cattle Information Service manager for Shropshire, Midlands.