New tools for managing reproduction

Abstract

A series of biological events must occur before pregnancy can be established. Female cattle are anoestrus after parturition and cannot become pregnant. Once animals begin to cycle, then the oestrous cycle can be effectively controlled through hormonal treatments. Multiple drugs can be delivered into the vagina by plastic devices that contain physical pumps. These new devices will decrease animal handling before insemination. New chemical formulations may make synchronization products easier to use as well. Classical technologies for oestrous detection depend on mounting activity of cows. Newer methods of electronic oestrous detection measure the number of mounts that each cow receives. More modern approaches to oestrous detection capitalise on animal biology instead of the behavioural patterns of the cow.

Artificial insemination is widely practiced in animal agriculture. Increasing sperm lifespan in the female reproductive tract would greatly simplify artificial insemination, but a method to increase sperm lifespan has not been developed. In vitro embryo production has the capacity to provide a large number of embryos at a relatively low price. These low-price embryos can be used on low fertility cows that are incapable of producing a viable embryo.

Greater intensification is associated with earlier pregnancy diagnosis. Ultrasonography can be used to detect earlier pregnancies in cattle. A blood test for pregnancy may allow for even earlier diagnosis. If pregnancy tests for maternal recognition proteins can be developed, then non-pregnant cows could be identified 18 days after first insemination. Beginning a rapid resynchronisation program on day 18 would lead to a second insemination of non-pregnant cows within 21 days of first service.

The advent of genome technologies has placed renewed emphasis on understanding the relationship between animal genetics and reproduction. Genetic selection for improved fertility is possible. New genes that have major effects on reproduction have been discovered.

A combined approach involving reproductive genetics, oestrous cycle control, in vitro embryo production, early pregnancy detection and automated animal handling will improve reproductive management in future herds.