2013 Annual Report
1a.Objectives (from AD-416):
The overall objective of this project is to determine the dietary energy and protein that is optimal for gilt development.
1b.Approach (from AD-416):
This project will be done in collaboration with a commercial collaborator (Murphy Brown), scientists at University of Nebraska-Lincoln and Clemson University. The experiment is designed as a 2 x 3 factorial with two levels of lysine (limiting amino acid) and three levels of metabolizable energy, which have been set by the National Pork Board. Each dietary treatment will be provided to 200 gilts from day 100 of age until day 260 of age. Feed intakes will be measured on a pen basis. Gilts will be weighed and ultrasounded at 4 week intervals. Boar exposure and estrus detection will begin at 160 days of age and age at puberty, number of cycles and cycle length will be recorded. At 260 days of age, gilts will be slaughtered at one or more Farmland plants and reproductive tracts will be assessed for proper development and uterine lengths will be measured. A sample of mammary gland tissue will be collected at slaughter for proximate analysis. A subset (1 out of every tenth gilt) will be processed for ovarian, uterine and mammary gland histological assessment. A sample of uterus from each gilt will be collected for DNA isolation. Data will be used to validate genetic markers for puberty that were discovered at USMARC and University of Nebraska-Lincoln. In addition, data collected will provide phenotypic data for Illumina Swine beadchip genomic analysis for puberty, growth traits, and uterine length.
The National Pork Board set up a Sow Lifetime Consortium of researchers and several discussions have been undertaken to improve and define the experimental details of this project. A well defined protocol was generated from these discussions. After funding was acquired, scientists from University of Nebraska-Lincoln declined to participate in the project. Discussions have occurred with scientists at Iowa State University to replace their needed expertise in the trial, and the project was modified reflecting their participation and approved by the National Pork Board. Gilts for the trial were born in Utah beginning June 4th, 2013, and a variety of litter of origin information was collected (number born alive, total born, number of females and males, day 1 weights for every piglet, crossfostering, and weaning weights for every piglet). A blood sample was collected from each gilt to be used in the trial (1700) and immunocrits have been run to assess whether each piglet received adequate colostrum. Piglets were weaned during the first and second weeks of July 2013 and 1300 gilts were transported to Goldfield, Iowa, which is the site of the trial. Dietary treatments are set to begin in September 2013.