Improving fertility and also calving rates of dairy herds in South West Wales through a method of early pregnancy diagnosis using pregnancy specific protein B (PSPB)

Pregnancy specific protein B (PSPB) can be found in cow’s blood as early as 28-30 days post service which has the potential to be an early indicator of pregnancy. Poor fertility is an expensive health issue on dairy farms and it’s important to find a solution to improve this in herds. Improved fertility and earlier pregnancy diagnosis (PD) by testing the PSPB in the blood could potentially improve conception rates, reducing the calving interval on farm and improve milk yields as a consequence. Early diagnosis of a cow not becoming pregnant by using the PSPB method also means that the farmer can investigate the reasons why the cow is not pregnant and make appropriate changes at an earlier stage.

Four farmers in south Wales milking a combined total of approximately 2000 cows and all operating a different production system are investigating whether PD by using PSPB will lead to improved fertility. At the moment, they all use uterine examination by palpitation or ultrasound or observation of oestrus as the method of pregnancy diagnosis on farm. These methods have been standard practice on farms for many years and although rectal palpitation is cheap and convenient for the farmers, it can only diagnose pregnancy from 5-6 weeks (35 – 42 days) post service.

The project plan:

• In this 12 month project all breeding cows will be split into two random groups. One group will be pregnancy diagnosed using ultrasound scanning and the other will be pregnancy diagnosed using PSPB.
• The farmers will then carry on with their usual breeding programme on farm. For the cows in the PSPB group the cows will be blood sampled by a vet as close to 28 days post service as possible.
• Following the 12 months of testing the data from all four farms will be analysed and a comparison will be made between ultrasound scanning and PSPB. A cost benefit analysis will also be carried out.

The AHDB reports that poor fertility on farm currently equates to a national average of 3.5p/litre in increased costs, as a result of long calving intervals and failure to conceive. Adopting a method of early pregnancy, or lack of pregnancy, could also reduce costs related to:

• Loss of milk production through too many dry days or peak yield traded for later lactation yield.
• Disruption to the calving season and milk production pattern.
• Enforced culling due to late detection of non-pregnant cows, resulting in more replacements required (bought or reared).
• Addressing infertility and re-breeding animals using AI etc.
• Veterinary treatment.