Effects of Nursery Floor Space Allowance on Growth, Physiology, and Immunology in Replacement ...

77 Pages·2013·0.64 MB·English

Effects of Nursery Floor Space Allowance on Growth, Physiology, and
Immunology in Replacement Gilts

Stuart R. Callahan

Thesis submitted to the faculty of the Virginia Polytechnic Institute and State
University in partial fulfillment of the requirements for the degree of

Master of Science
In
Animal and Poultry Sciences

Mark J. Estienne, Chair
James W. Knight
Cynthia M. Wood

September 19, 2013
Blacksburg, VA

Keywords: pig, floor space, nursery, replacement gilt

Copyright © 2013 Stuart R. Callahan
Effects of Nursery Floor Space Allowance on Growth, Physiology, and
Immunology in Replacement Gilts
Stuart R. Callahan
Abstract
In U.S. swine herds, sow removal rates due to death and voluntary and involuntary
culling exceed 50% annually. This loss poses an economic problem for producers because the
cost of acquiring replacement females is great. Although research has shown that crowding in the
nursery has negative impacts on growth, research describing effects of crowding on subsequent
reproductive performance and longevity in sows is lacking. This experiment was conducted to
determine the impacts of crowding during the nursery phase of production on growth,
physiology, and immunology in replacement gilts. Gilts (22.3 ± 3.2 d of age and 5.6 ± 0.6 kg
BW) were subjected to floor space allocations of 0.15, 0.19, or 0.27 m2/pig during a 7-wk
nursery period. Floor space allocations were achieved by altering the number of pigs per pen (14,
11, and 8 gilts/pen, respectively). As was expected, reduced floor space allowance in the nursery
negatively affected growth performance although there was inconclusive physiological and
immunological evidence to suggest that pigs were experiencing highly stressful conditions.
Although feed intake was not measured, changes in blood counts and blood chemistry for gilts
allowed reduced floor space were similar to other studies that reported negative effects of
crowding on feed consumption. Further study of the gilts involved in this study will aim to
determine if there are any links between the effects of crowding during the nursery and
subsequent reproductive performance and longevity in the breeding herd.
Acknowledgements
Thank you to:
Mom and Dad: for giving me plentiful opportunities throughout my life and the chances to
make my own decisions. Without your love and support I would not be where I am today.
Dr. Mark Estienne: for taking me on as your graduate student and giving me the opportunities
to work for and learn from you. I am very grateful for all of your advice, guidance, and support.
Dr. James Knight: for making learning fun and challenging, I really learned a lot from you.
Thank you for your input and suggestions as a part of my committee.
Dr. Cindy Wood: for teaching me the ins and outs of the swine industry. Thank you for your
guidance and support as part of my committee.
Dr. Ashley DeDecker: for your continued guidance and support from start to finish on this
project.
Dr. Merlin Lindemann: for providing support of this project and expertise of previous research
regarding the effects of crowding during the nursery phase of production.
Amanda Cross: for your help on weighing days. I’m glad we could be a part of the “10k
Project” together.
Beata, Pepe, Edgar, Nancy, and Ezequiel: for the many times you all helped me throughout
the course of my project. Thank you for taking me in as a part of your farm crew.
Lee Johnson: for allowing me to use your lab space and for your assistance running RIAs.
Ellie Stephens: for all of your guidance and assistance throughout the graduate school process.
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Debbie Estienne: for your guidance no matter if I was in Blacksburg or Suffolk.
Carolyn Crowder: for your assistance and making sure I had all of my paper work in order.
National Pork Board: for funding this project.
Virginia Pork Industry Board: for funding this project.

iv
Table of Contents
Abstract ....................................................................................................................................................................... ii
Acknowledgements .................................................................................................................................................... iii
Table of Contents ......................................................................................................................................................... v
List of Figures ........................................................................................................................................................... vii
List of Tables ................................................................................................................................................................ x
List of Abbreviations ..................................................................................................................................................xi
Chapter 1. Introduction .............................................................................................................................................. 1
Chapter 2. Literature Review ..................................................................................................................................... 3
Sow Longevity .......................................................................................................................................................... 3
Introduction .......................................................................................................................................................... 3
Annual culling rates ............................................................................................................................................. 4
Reasons sows are culled ....................................................................................................................................... 5
Economic impact of poor longevity ..................................................................................................................... 6
Developmental Impacts on Growth and Reproductive Performance ........................................................................ 7
Prenatal environment ........................................................................................................................................... 7
Neonatal environment .......................................................................................................................................... 9
Nursery environment .......................................................................................................................................... 11
Nursery group size ........................................................................................................................................ 12
Nursery floor space ....................................................................................................................................... 13
Grow-finish environment ................................................................................................................................... 15
Quantifying Stress in Swine.................................................................................................................................... 17
Conclusion .............................................................................................................................................................. 22
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Chapter 3. Effects of Nursery Floor Space Allowance on Growth, Physiology, and Immunology in
Replacement Gilts ...................................................................................................................................................... 23
Introduction ............................................................................................................................................................. 23
Materials and Methods ............................................................................................................................................ 24
Animals, Housing, and Experimental Design .................................................................................................... 24
Body Weight Measurements .............................................................................................................................. 25
Blood Sample Collection and Analyses ............................................................................................................. 25
Necropsy ............................................................................................................................................................ 26
Statistical Analyses ............................................................................................................................................ 26
Results..................................................................................................................................................................... 27
Growth Performance .......................................................................................................................................... 27
Complete Blood Counts ..................................................................................................................................... 27
Blood Chemistry Profile .................................................................................................................................... 29
Serum Cortisol ................................................................................................................................................... 31
Necropsy ............................................................................................................................................................ 32
Discussion ............................................................................................................................................................... 32
Conclusion .............................................................................................................................................................. 37
Figures ........................................................................................................................................................................ 38
Tables .......................................................................................................................................................................... 55
Literature Cited ......................................................................................................................................................... 60

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List of Figures
Figure 1. Effect of floor space allowance size day (P = 0.04) on total neutrophil
concentrations for small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD)
m2/pig during the nursery phase of production. .............................................................................38
Figure 2. Effect of floor space allowance size day (P < 0.05) on segmented neutrophil
(SEG) concentrations for small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27
(LD) m2/pig during the nursery phase of production .....................................................................39
Figure 3. Effect of floor space allowance size day (P < 0.01) on neutrophil to lymphocyte
ratio (N:L) for small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD)
m2/pig during the nursery phase of production. .............................................................................40
Figure 4. Effect of floor space allowance size (P < 0.05) on mean corpuscular volume (MCV)
for small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig during
the nursery phase of production .....................................................................................................41
Figure 5. Effect of floor space allowance size (P < 0.05) mean corpuscular hemoglobin
(MCH) for small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig
during the nursery phase of production .........................................................................................42
Figure 6. Effect of floor space allowance size (P < 0.05) on reticulocyte % (RETIC%) for
small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig during the
nursery phase of production ...........................................................................................................43
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Figure 7. Effect of floor space allowance day (P = 0.03) on banded neutrophil (BAND)
concentrations for small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD)
m2/pig during the nursery phase of production. .............................................................................44
Figure 8. Effect of floor space allowance day (P < 0.05) on monocyte (MONO)
concentrations for small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD)
m2/pig during the nursery phase of production. .............................................................................45
Figure 9. Effect of size day (P = 0.03) on reticulocyte percent (RETIC%) for small, medium,
and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig during the nursery phase of
production ......................................................................................................................................46
Figure 10. Effect of size day (P = 0.03) on reticulocyte number (RETIC#) for small, medium,
and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig during the nursery phase of
production ......................................................................................................................................47
Figure 11. Effect of floor space allowance size (P = 0.02) on globulin concentrations for
small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig during the
nursery phase of production ...........................................................................................................48
Figure 12. Effect of floor space allowance day (P < 0.01) on aspartate
aminotransferase/glutamic-oxalacetic transaminase (AST/GOT) concentrations for small,
medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig during the nursery
phase of production ........................................................................................................................49
Figure 13. Effect of floor space allowance day (P = 0.03) creatine kinase (CK) concentrations
for small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig during
the nursery phase of production .....................................................................................................50
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Figure 14. Effect of floor space allowance day (P = 0.02) on chloride (Cl) concentrations for
small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig during the
nursery phase of production ...........................................................................................................51
Figure 15. Effect of size day (P < 0.01) on glucose concentrations for small, medium, and
large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig during the nursery phase of
production ......................................................................................................................................52
Figure 16. Effect of floor space allowance size day (P = 0.03) on serum cortisol
concentrations for small, medium, and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD)
m2/pig during the nursery phase of production ..............................................................................53
Figure 17. Effect of floor space allowance size (P < 0.01) on liver weight for small, medium,
and large gilts housed at 0.15 (HD), 0.19 (ND), or 0.27 (LD) m2/pig during the nursery phase of
production ......................................................................................................................................54

ix
List of Tables
Table 1. Growth performance for small (S)-, medium (M)-, and large (L)-sized gilts housed at
0.15, 0.19, and 0.27 m2/pig ............................................................................................................55
Table 2. Complete blood counts for small (S)-, medium (M)-, and large (L)-sized gilts housed at
0.27 (n = 18), 0.19 (n = 18), and 0.15 (n = 18) m2 floor space/pig ................................................56
Table 3. Blood chemistry profiles for small (S)-, medium (M)-, and large (L)-sized gilts housed
at 0.27 (n = 18), 0.19 (n = 18), and 0.15 (n = 18) m2 floor space/pig ............................................57
Table 4. Serum cortisol concentrations for small (S)-, medium (M)-, and large (L)-sized gilts
housed at 0.27 (n = 18), 0.19 (n = 18), and 0.15 (n = 18) m2/pig ..................................................58
Table 5. Organ measurements for small (S)-, medium (M)-, and large (L)-gilts housed at 0.27 (n
= 10), 0.19 (n = 10), and 0.15 (n = 10) m2/pig ...............................................................................59
x