Vaginal and vestibular electrical resistance as an alternative marker for optimum timing of artificial insemination with liquid-stored and frozen-thawed spermatozoa in sows.

Development of a pen-side test to objectively determine the ideal time for artificial insemination (AI) in the sow would save producers time and money. Current processes rely on identification of oestrus via subjective behavioural and physiological markers that are indicative of high blood oestrogen concentrations. This study attempted to use measurements of electrical resistance (ER) in the cervical mucus to pinpoint timing of AI accurately enough to lead to equivalent pregnancy rates as a natural mating. Thirty-six sows were divided into 3 groups and observed for signs of oestrus. Seven sows did not show any oestrus behaviour and were excluded from the study. The remaining 29 sows were inseminated via natural mating and conventional oestrus detection (n = 14), or inseminated artificially with either liquid-stored semen (n = 8) or frozen-thawed semen (n = 7) according to timing indicated from electrical resistance measurements in the vagina and vestibule. Sows that were artificially inseminated on the basis of the electrical resistance readings had a lower pregnancy rate (P = 0.034) and less piglets born alive per litter (P < 0.05) than those that were naturally mated according to a conventional oestrus detection regime. However, the pregnancy rate and total piglets born alive did not differ between the two groups that underwent artificial insemination. Change in electrical resistance in the vagina has the potential to accurately predict ovulation timing, but more work is required to refine the timing of AI in relation to the readings before the technique can be adopted by industry.

Impact of Non-Confinement Accommodation on Farrowing Performance: A Systematic Review and Meta-Analysis of Farrowing Crates Versus Pens.

There are conflicting reports regarding the effect of farrowing house accommodation on piglet performance. The aim of this investigation was to use a systematic review and meta-analyses to summarise the results of publications that focused on direct comparisons between full confinement conventional crates and various designs of loose-housed farrowing pens from loading until weaning. Literature searches in Scopus, BIOSIS Previews, Cab Abstracts, and Web of Science identified 6695 articles. Twenty-two publications were retained for the systematic review and individual meta-analyses after screening for inclusion criteria. The random effects meta-analyses were performed on crate versus pen for number of piglets born alive, number of stillborn piglets, pre-weaning mortality, and number of piglets weaned. Additionally, the modifiers of confinement length (no confinement from loading until weaning or partial confinement for shorter periods of time in the early stages post parturition), enrichment (no enrichment or enrichment provided), and pen size (small, medium, or large) were examined. There was a 14% increase in the relative risk of piglet mortality in farrowing pens when they were compared with crates (p = 0.0015). The number of stillborns per litter was not different between the pen and crate. However, when providing enrichment in the pens, there was an increase in stillborns within farrowing crates versus pens (p = 0.009). There was no overall effect on piglets that were born alive or number weaned. As there is no difference between piglets born alive and mortality is significantly higher in farrowing pens, a reduction in the number of piglets weaned was expected but not observed, which was possibly due to the lack of weaning details provided in the publications. This was the first systematic review and meta-analysis conducted on the performance of farrowing accommodation and identified that farrowing pens do compromise post-natal piglet survival. Future efforts should focus on improving sow comfort in the farrowing crate to maximize both piglet and sow welfare.

Effect of Dextrose Supplementation in the Pre-Ovulatory Sow Diet to Reduce Seasonal Influences on Litter Birth Weight Variation.

In this experiment, we proposed two hypotheses: birth weight variation would increase in litters from sows bred in summer, and dextrose supplementation during the wean to mate period would ameliorate this manifestation of seasonal infertility. Five hundred and ninety-one multiparous sows were allocated to Control; standard diet, or Dextrose; control +5% dextrose diets from weaning until insemination during summer and winter. Dextrose sows farrowed 1.0 and 1.4 more total pigs born and pigs born alive than Control sows, respectively (p < 0.05). There was a tendency for a higher co-efficient of variation (CV) birth weight in summer than winter (16.6 ± 0.4 versus 15.8 ± 0.4; p = 0.1), but no effect of treatment or interaction between treatment and season was observed. Piglet average daily gain was unaffected in those born to sows bred in summer, but when born to sows bred in winter, Dextrose piglets grew 23 g per day faster than Control (p < 0.05). This experiment identified evidence for increased birth weight CV in sows bred during the summer months despite the reduced litter size, suggesting that this is another way seasonal infertility can manifest.