Pig Lameness and Diagnostic Lab Views - Dr. Darin Madson, Veterinary Diagnostic & Production Animal Medicine, College of Veterinary Medicine, Iowa State University, from the 2013 Allen D. Leman Swine Conference, September 14-17, 2013, St. Paul, Minnesota, USA. More presentations at http://www.swinecast.com/2013-leman-swine-conference-material

1. Feeding for Optimal Bone Strength
2013 Allen D. Leman Swine Conference
What we are seeing at the
diagnostic laboratory
Darin Madson
madson@iastate.edu
Veterinary Diagnostic Laboratory
Iowa State University

2. What we are seeing
• Increased clinical investigations/submissions
• Suggesting an issue or production concern
• Different from “normal/routine” submissions
• Suboptimal clinical lameness assessments
• With improper sample submission
• Wide variation in bone quality
• The gamut of lameness etiologies found
• Metabolic condition, OCD, and Mycoplasma sp.
Veterinary Diagnostic Laboratory
Iowa State University

3. Bone – “the organ”
• Bone is constantly being remodeled
– Throughout life; even after growth as stopped
– Bone is dynamic  tells a story!
•
•
•
•
Mechanical stress
Decreased nutrition
Environmental stress
Disease
– Can be seen microscopically
• Arrest and reversal lines
Veterinary Diagnostic Laboratory
Iowa State University

4. What is metabolic bone disease?
• Disturbances related to:
1.
2.
3.
4.
Vitamin D
Can be combinations of these
Calcium
Phosphorus
Parathyroid hormone
• Results in
1. Depletion of bone mineral storage
2. Delayed formation/modeling
Veterinary Diagnostic Laboratory
Iowa State University

5. What is metabolic bone disease?
• Terminology
– Rickets
• Abnormal endochondral ossification in a growing animal
– Defective mineralization of growing bone
– Osteomalacia
• Similar to rickets, but in adult animals
– Defective mineralization of bone remodeling
– Fibrous osteodystrophy
• Extensive bone resorption with replacement by fibrous connective
tissue
– Osteoporosis/Osteopenia
• Reduced bone mass
– Quality of remaining bone is normal
Veterinary Diagnostic Laboratory
Iowa State University

6. What is metabolic bone disease?
Common mechanisms:
1. Inadequate dietary supplementation of vitamin D3
2. Inadequate absorption of phosphorus due to low
phosphorus in diet, phosphorus bound to phytate and
therefore unavailable, and inadequate or ineffective
phytase usage
3. Imbalance of feed calcium to phosphorus ratio; improper
formulation of Ca:P ratio in diet (should be roughly 1.2:1)
4. Inadequate dietary calcium can also contribute to rachitic
lesions, though these are also often confounded by
accompanying osteoporosis.
Veterinary Diagnostic Laboratory
Iowa State University

7. Potential industry issues
• Swine diets  maximum growth
• Not bone strength
• Ingredient costs
• Alternative feedstuffs
• Variability in feedstuffs
• Amount of ingredient
• Process for inclusion (pelleting)
• NRC values (outdated?)
Veterinary Diagnostic Laboratory
Iowa State University

8. Clinical signs
Metabolic bone disease
• Clinical signs are variable
• Sudden death (found dead)
• Tremors/seizures (CNS like disease)
• Muscle fasciculations/tetany
• Weakness
• Lameness
• Painful gait and reluctancy to move
• Bone fractures
Veterinary Diagnostic Laboratory
Iowa State University

9. Clinical signs
Veterinary Diagnostic Laboratory
Madson et al. 2012
Iowa State University

10. Broken bone
Rachitic rosary
Veterinary Diagnostic Laboratory
Iowa State University

11. Diagnostic testing
• Assessing rib strength
Rickets (growing pigs)
Phosphorus
Rubbery bones
Calcium
Fragile bone; Break easy, but snap
Vitamin D
Rubbery bones
Veterinary Diagnostic Laboratory
Iowa State University

12. Diagnostic testing
• Bone analysis
– Need to know the processes
• Wet weight or dry-fat free!!!
Dry, fat free
Wet weight
Swine; rib bone
Bone ash
58-62 %
Bone density
1.4-1.5 g/ml.
Bone ash Calcium
32-39%
Swine; rib bone
Bone ash
25-30 %
Bone density
1.4-1.5 g/ml.
Bone ash Calcium
32-39%
Bone ash Phosphorus 13-22%
Bone ash Phosphorus 13-22%
Veterinary Diagnostic Laboratory
Iowa State University

13. Diagnostic testing
Wet weight
Bone Ash - Summary of 169 porcine cases
Above noraml (>35%)
Normal (25-35%)
Total
Deficient (below 25%)
0
20
40
60
80
100
number of test results within each range
Veterinary Diagnostic Laboratory
Iowa State University

14. Diagnostic testing
• Serum
– Calcium
– Phosphorus
– Alkaline phosphate (ALP)
» Increased with bone resorption
Analyte
Vit D
deficiency
Calcium
deficiency
Phosphorus
deficiency
Calcium
⬇
⬆, ⬌
⬆
⬇
⬆, ⬌
⬆
⬆, ⬌
⬇
⬆
Phosphorus
ALP
Veterinary Diagnostic Laboratory
Iowa State University

15. Diagnostic testing
• Serum Vitamin D
– Heartland Assays. Inc (Ames, Iowa)
– Ron Horst
Darin’s Thought
Age of animal
Neonate
10 days
3-4 weeks old
Finishing pigs
Mature
Parturition
25-OH-D3 ng/ml
5-15
8-23
25-30
30-35
35-70
35-100
Stay above 15 ng/ml
Veterinary Diagnostic Laboratory
Iowa State University

16. Diagnostic testing
• Urine?
Hagemoser et al. 2000
Veterinary Diagnostic Laboratory
Iowa State University

17. Vitamin D research - ISU
• Main goal
– Assess vitamin D levels across different ages of pigs in the
Midwest
• Two different time points
– Once in January (2011)
– Once in July (2011)
• Ages of animals assessed in the surveillance
–
–
–
–
–
3 week old pigs
~11 week old pigs
Market hogs
Gestation sows
Boars
8 samples from 15 sites in each
age group at each time point
1,200 total samples tested
600 samples tested in January 2011
600 samples tested in July 2011
Veterinary Diagnostic Laboratory
Iowa State University

18. Results
**
*
35 ng/ml
15 ng/ml
5 ng/ml
Veterinary Diagnostic Laboratory
ANOVA - * & ** indicate significant differences between January and June samples (p < 0.01)
Iowa State University

19. 2719 total samples
Veterinary Diagnostic Laboratory
Iowa State University

20. Vitamin D research – ISU take 2
Objective of proposal
– Assessing the quality of vitamin D from
multiple suppliers overtime
• 5 feed manufactures
• Sample bulk vitamin D 1x per month
– Mixed from multiple locations
• Sampling for 12 months
– October 2011-September 2012
Veterinary Diagnostic Laboratory
Iowa State University

21. Vitamin D research – ISU take 2
• Results
– No company was found
to be significantly lower
than 500,000 IU
• No difference in US vs.
Foreign vitamin D
manufactures
– Month was found to
be significant
• P= 0.0022
• Storage???
Veterinary Diagnostic Laboratory
Iowa State University

22. Confounding issues
• Lameness failures
– Clinical assessment
– Age, weight, feed, growth rate, and watching them walk
– Gross assessment
– It is more than hacking off a limb
– Sample submission is key
– Complexity
– Correct samples
– Other differentials
– Knowing what to look for
Veterinary Diagnostic Laboratory
Iowa State University

23. Confounding issues
Ytrehus et al. 2007
Osteochondrosis
Veterinary Diagnostic Laboratory
Iowa State University

24. Confounding issues
Mycoplasma hyosynoviae
Hygroma formation
Veterinary Diagnostic Laboratory
Iowa State University

25. Take home points
• Lameness is an industry issue
– Multiple factors are associated
• Infectious or nutritional
• The “insult” may have occurred previously
• Clinical assessments are important
• Multiple samples are needed
• Location can vary significantly in clinical pigs
• Understand potential confounding problems
– Are the findings the “real” cause of the lameness
Veterinary Diagnostic Laboratory
Iowa State University

26. Thank you for your attention!
QUESTIONS?
Veterinary Diagnostic Laboratory
Iowa State University