The effects of intermittent suckling protocols on reproductive performance in primiparous sows

• Author / Creator

  Blanes, Milena S

• In pig production, sow reproductive efficiency is a key contributor to breeding herd productivity. A major challenge in the implementation of alternative sow housing and piglet management systems is the maintenance of production efficiency. Conventionally, sows are only bred once they come into estrus following piglet weaning. However, the ability to breed sows during lactation creates the potential to improve piglet welfare and maintain annual sow productivity. Lactational management regimes, such as intermittent suckling (IS), allow sows to return to estrus and be bred during lactation, by separating nursing sows and piglets for several approximately 8 hours each day. For this thesis research, we compared IS protocols to conventional weaning (Control) and their influence on the performance of primiparous (PP) sows. The primary objective was to analyse the effects of inducing lactational estrus and breeding during lactation on PP sow reproductive performance, especially on embryo development and survival. This work involved initially assessing the effects of applying IS protocols in PP sows by evaluating their reproductive responses (e.g. rate of lactation estrus, pregnancy, ovulation, placental development and embryo survival rate) as well metabolic status of sows. Then the effects of IS protocols on conceptus quality were analyzed at a molecular level through embryonic gene expression analysis and the effect of IS on litter sex ratio and sex specific embryonic gene expression. The results of this research revealed that 61% (35/57) of PP sows exposed to IS exhibited estrus during lactation. Subsequent assessment of IS sows bred during lactation compared to Control sows demonstrated that IS did not negatively impact overall reproductive performance (i.e. pregnancy rates, embryonic survival). It was observed that placental development at day 30 (D30) of gestation, as represented by placental volume, was reduced in IS sows compared to Control sows. However, IS treatment did not appear to impact embryonic development. Molecular analysis of D30 embryos for IS and Control sows revealed no significant differences in gene expression across treatments and had no impact litter sex ratios. Additionally, metabolic analysis showed that the 39% of sows which did not response to IS were more metabolically challenged during lactation than sows that responded to IS and demonstrated lactation estrus. This result indicates that metabolic status and nutritional management during lactation influence response of sows to IS protocols. Overall, the results of my thesis research demonstrate that the application of IS protocols to induce estrus and breed PP sows during lactation does not influence embryonic development or negatively impact sow reproductive performance. However, metabolic status and nutritional management during lactation play an important role in the response of sows to IS protocols. Further research is needed to assess the relationship between the metabolic status and response of PP sows to IS, as well as the feasibility of applying IS protocols in large scale commercial production systems.

• Subjects / Keywords

  • Sow lactation
  • Gene-expression
  • Lactation estrus
  • Intermittent suckling

• Graduation date

  Fall 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3H98ZT00

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.