Diagnosis can be made as early as five to six weeks

Pregnancy tests for cattle will soon become easier with the availability of a new kit being developed by scientists from the Centre for Cellular and Molecular Biology (CCMB), Hyderabad. Using ELISA to test a sample of dung can reveal the pregnancy at an early stage as compared with existing methods.

In what is quite novel, the group has identified a biomarker, a metabolite, which is found in high concentrations in dung within 3-4 weeks of pregnancy. When this dung sample is tested using the ELISA method, there is a colour change to indicate presence of the specific metabolite. Further, the paper-based microfluidic kit being developed is constructed so as to enable reading out the result.

Timely detection of pregnancy in cows and buffaloes is important to maximise reproduction and milk production. According to G. Umapathy from CCMB, this can help in shortening calving interval and planning for rebreeding at the earliest oestrus cycle.

Easy verification

Though they have studied this aspect of many animals, the group focused on cattle, as the livestock sector is poorly organised. In currently available methods, pregnancy detection in cattle requires veterinary expertise or lab facilities. The present method not only detects pregnancy at an earlier stage, it also makes it possible for breeders to independently carry out the process of detection. With this view, the group is working on a kit developed by Amit Asthana and Ch Mohan Rao, also from CCMB.

Pregnancy kit

They adapted the laboratory ELISA protocol to a simple paper-based device. The special feature of this system is that while normally any moisture placed on a paper would be sucked in through capillary action, this device shows a guided flow. “We use hydrophobic barriers in such a way that the flow is regulated and the colour change in the paper can be used as a read out,” says Dr Asthana, in an email to this correspondent.

The proof of principle of the kit is established. “However, we are trying to further simplify and improve its efficacy. A multi-centric extensive evaluation is necessary before the product can be released in the market,” says Dr Ch Mohan Rao, in an email. The group is in the process of filing a patent for this system.

While this kit is specifically designed to test for pregnancy in cattle, the group is concerned about detecting pregnancy in wildlife in general. It is not easy to do this, as animals need to be anaesthetised and blood samples drawn for testing in existing methods. The anaesthesia and frequent drawing of blood can leave the animal stressed out. “Our laboratory has been investigating ways of non-invasively estimating hormone profiles in wildlife,” says Dr Umapathy.