PHYSIOLOGICAL APPROACHES TO INCREASE THE EFFICIENCY OF PORK PRODUCTION THROUGH IMPROVED NUTRITIONAL AND REPRODUCTIVE COMPETENCE
Location: Reproduction Research
Title: Development of Neonatal Piglets Following Reciprocal Embryo Transfers Between Meishan and White Crossbred Gilts
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 22, 2008
Publication Date: June 20, 2009
Citation: Miles, J.R., Vallet, J.L., Ford, J.J., Freking, B.A., Cushman, R.A., Oliver, W.T., Christenson, R.K. 2009. Development of Neonatal Piglets Following Reciprocal Embryo Transfers Between Meishan and White Crossbred Gilts [abstract]. Proceedings of VIIIth International Conference on Pig Reproduction, Banff, Alberta, Canada, p. 148.
Sow productivity has a significant economic impact on the swine industry and is influenced by a number of factors including preweaning piglet mortality. The greatest susceptibility for preweaning mortality occurs in low birth weight piglets. However, despite their overall decreased weights, Meishan (MS) piglets have lower preweaning mortality rates compared with Western breeds. The objective of the current study was to determine the contributions of the piglet and maternal genotypes and their interactions on the development of neonatal piglets pertaining to preweaning survival using reciprocal embryo transfer between MS and White crossbred (WC) gilts.
Twenty-five successful pregnancies were produced by embryo transfer in two farrowing seasons. All piglet and maternal genotype combinations were represented; MS x MS (n=4 litters), WC x WC (n=7 litters), MS x WC (n=7 litters), and WC x MS (n=7 litters). At approximately 24 h of age (day 1), piglets were weighed and a blood sample was taken. Hematocrit, hemoglobin, glucose, nitrogen, albumin, free fatty acids, and cortisol were measured in all blood samples. In addition, representative piglets from each litter were sacrificed and body measurements (i.e., organ weights, tissue glycogen content, and body composition) were determined. All data were analyzed for analysis of variance using MIXED model procedures.
Both WC piglet (P=0.01) and maternal (P=0.004) genotypes had significant effects on piglet weights demonstrating that not only were WC piglets heavier than MS piglets but piglets from WC gilts were heavier than piglets from MS gilts. In addition, WC piglets had increased (P=0.04) eviscerated body weight compared with the MS piglets. However, total visceral weight prior to emptying the stomach was increased (P=0.01) in the MS piglets despite no significant differences in organ weights between WC and MS piglets. Interestingly, stomach content weight was greater (P=0.02) in the MS piglets, suggesting greater milk intake in MS piglets. Furthermore, the percentage of fat and nitrogen within the body composition were greater (P<0.02) in the MS piglets, indicating greater energy stores. Bicep femoris and longissimus dorsi glycogen concentrations were greater (P<0.01) in WC piglets compared with MS piglets, suggesting that MS piglets may be more active. Serum albumin levels were increased (P=0.04) in MS piglets compared with WC piglets. Significant (P<0.02) fetal by maternal interactions were observed for hematocrit and hemoglobin in which the greatest levels were observed in MS piglets from WC gilts. A similar tendency (P=0.06) was observed in plasma urea nitrogen levels. In conclusion, the results of this study indicate that the MS breed serves as a good model for studying preweaning survivability and that focusing on components relating to energy stores, oxygen carrying capacities, appetite, and activity has the potential to identify factors associated with piglet survival.