student profile: Miss Dannielle Glencorse


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Thesis work

Thesis title: Biological markers to quantify oestrus and predict insemination timing in sows for improved fertility using frozen-thawed boar spermatozoa

Supervisors: Roslyn BATHGATE , Christopher GRUPEN

Thesis abstract:

Within the pork industry, the detection of oestrus occurs predominantly by observing sows for behaviours that demonstrate sexual receptivity. Although standing heat can be used to identify the oestrus period, this technique cannot be used to precisely determine the optimum timing for insemination and cannot guarantee sperm will be delivered close to the ovulation of an ovum. As a result, once sexual behaviour is detected, it is followed by a double insemination regime over the 2-3 day oestrus period to account for this imprecise and variable methodology. Multiple inseminations result in wasted semen doses and high labour inputs which could be prevented with the development of an accurate oestrus detection tool.

This project is focused on evaluating existing methods of oestrus detection and developing novel tools that enable producers to quickly and easily determine the optimum time for mating. There are several physiological changes that produce biological markers during oestrus due to hormonal fluctuations.

This research focuses on several markers during oestrus; electrical resistance of the reproductive tract, mucus composition, body temperature and fine behaviour changes. Identifying correlations between these biolgocial markers and the timing of oestrus and ovulation will enable accurate, precise inseminations to maximise productivity and improve oestrus detection on farm. 

Sows undergo oscillating patterns during oestrus associated with elevated hormone levels. These hormones cause behavioural changes that can be monitored via acceleration based movement technology. During oestrus, blood flow to the female reproductive tract increases causing reddening and swelling of the vulva. This inflammatory-like response leads to an elevated vulva temperature. Similarly, the microscopic appearance of cervical mucus is altered during oestrus due to a larger proportion of mucins and salts within the secretion. This composition alters the ultra-structure of the mucus resulting in microscopically visible fern-like patterns and as result modifying the electrical resistance of the fluid. 

Despite the theoretical links between oestrus and these markers, exploration of the true correlation and variability within these physiological changes has not occurred. It will be possible to develop a simple, effective pen-side test for identifying the optimum time for insemination. These techniques can be applied to make unbiased, precise decisions on insemination timing in an automated system that continuously collects data. 
This will potentially enable the use of single dose artificial insemination without a loss in fecundity, saving producers time and increasing profitability

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