Characterising the vaginal microbes of high and low producing Poll Merino and White Suffolk ewes

Summary

Gastrointestinal microbes and their manipulation to affect health and production has become a widely researched area, particularly in production animals. However, there is no research into the vaginal microbiota (bacteria) of Australian production sheep. Microbial diversity in lambs is acquired from the surrounding environment, including the ewe’s vagina during delivery and has potential implications for lifetime animal health and productivity.

This research sought to understand natural variation in the vaginal microbial population (bacteria) of ewes, as a potential pathway for manipulating microbial diversity in neonates. This could provide a pathway to influence future immune responses and animal performance.

Although there was no significant difference between breeds, this project was able to characterise the normal vaginal bacteria of non-pregnant ewes and demonstrate a rich microbial community that may positively influence lambs during birth.

Objectives

The objectives of this project were to:

• characterise the vaginal microbes of production sheep
• determine if vaginal microbes differ across sheep breeds (Poll Merino and White Suffolk) with differing growth and wool growth potentials
• determine a link between vaginal microbes and high and low producing animals.

Key findings

• Various vaginal bacteria were detected and able to be characterised in two breeds of ewe commonly used in Australia. This is the first report that characterises the vaginal microbiota of any domesticated Australian sheep.
• Despite difference in Australian Sheep Breeding Values (ASBV) of the sheep, there were no significant differences in ewe vaginal microbiota communities associated with ewe breed, or ewe production parameters within breed.
• The two breeds did, however, have different populations at the genus and species levels of bacteria. 

Benefits to industry

Manipulation of the microbiome is an emerging field of 'blue-sky' research in both the human and livestock sectors.

The results of this project represent the first opportunity to understand and manipulate neonatal microbial populations and production through the vaginal pathway. Identifying normal variations, and those caused by breed and production differences, in vaginal microbial population of ewes is important. These differences may potentially represent the first opportunity to understand and create beneficial neonatal microbial populations. This knowledge can then lead us in attempting to change lifetime population in the lamb gut, through manipulation of their populations near the time of birth.

MLA action

This is very early stage research so further work is required to achieve a commercial outcome, however, the two most likely pathways to impact are:

• genetic selection techniques
• the ability to immunise individual lambs through an inoculant/swab or alternative method.

MLA acknowledges the contribution of Dr Emma Greenwood and the University of Adelaide to the success of this project.

Future research

Several recommendations for further research have come out of this project:

• an ASBV study using more animals with industry relevant divergence in ASBV
• investigate other ASBVs likely linked with gut health
• utilise production records to analyse microbial data against, rather than ASBV data
• investigate pregnant ewes and their microbes' impact on production of offspring vaginal probiotics.