Relaxin as a tool for pregnancy diagnosis in al-pacas : evaluation of the point-of-care test FASTest Relaxin

Sammanfattning: The alpaca is a South American camelid that originates from the Andes. Their popularity and numbers in Sweden and other western countries have increased over the last few decades and they are kept as pets and for their fleece (fiber). Their reproduction differs from other ruminants in that they are induced ovulators, have a long gestational period, very rarely have twins and are older when they are first mated. Pregnancy losses are also common in alpacas, especially early pregnancy losses, with 10-50% of the losses occurring during the first two months of pregnancy. Therefore, alpacas have a poor breeding performance which makes advances in breeding slow. It is estimated that only half of the alpacas produce offspring each year. Because of this, an easily accessible, accurate and userfriendly tool for pregnancy diagnostics is crucial to be able to mate the female again during the season, thereby increasing the number of offspring produced by each alpaca and enabling the producer to reach breeding goals more effectively. The most commonly used methods for diagnosing pregnancies are observing the females’ behaviour towards males, ultrasonography and progesterone concentrations in plasma. Ultrasonography is considered as an accurate method, but as many veterinarians either lack the knowledge or equipment to perform it, it is still not a readily available tool for alpaca breeders. Measuring progesterone concentration or observing the females’ behaviour towards males are not entirely reliable since they are not specific for pregnancy. Relaxin, on the other hand, is a pregnancy-specific hormone produced in the utero-fetal-placental unit. Relaxin concentration in blood is used in pregnancy diagnostics for several species, including dogs and cats. Two scientific papers described the relaxin concentration in pregnant and non-pregnant alpaca females and showed a significant difference between them. In this study, the point-of-care test FASTest Relaxin, developed for dogs and cats, was evaluated as a tool in pregnancy diagnosis in alpacas. In total, 18 female alpacas were included in this study, which was conducted in the United Kingdom; 12 were 61-90 days pregnant and 6 were non-pregnant. The pregnancies were confirmed by ultrasonography on the same day as the blood samples were collected. The blood was centrifuged and the plasma was used in the FASTest Relaxin test, according to the test instructions, within 4 hours. Later, plasma was sent for quantitative analysis in a laboratory. All the results from FASTest Relaxin were negative even though the results from quantitative analysis showed levels of relaxin similar to those of dogs and cats. The conclusion is, therefore, that FASTest Relaxin does not work as a tool for diagnosing pregnancy in alpacas. In contrast, the quantitative analysis showed a clear difference in relaxin concentrations between pregnant and non-pregnant females.