Swine Clinical Nutrition Crash Course

• Swine clinical nutrition is the topic of a crash course.
• The presenter is Jordan Gebhardt, [email protected]
• The presentation date is February 27, 2025

Outline of Presentation

• General nutrition principles
• Common problems veterinarians might face
• Feed safety

Example Diet for Swine

• Diets are fed from 15 to 130 lbs bodyweight
• Key diet components are:
  • Energy
  • Protein/Amino Acids
  • Macro minerals
  • Vitamins/Trace Minerals
  • Additives

What Pigs Eat

• Cereal grain sources include:
  • Corn, Milo/Sorghum, and Wheat
• Other important components include:
  • Soybean meal
  • Dried distiller's grains with solubles (DDGS)
  • Specialty protein sources like processed soy products and animal by-products
  • Feed-grade amino acids produced through fermentation processes
  • Minerals, vitamins, and feed additives

Approach to Diet Formulation

• Energy level of diet is an important first step
• Determine how much lysine to add (first limiting amino acid)
• Also the ratio of other amino acids to lysine
• Determine phosphorous level in the diet, as well as amount of calcium to add (Ca:P ratio)
• Set levels of vitamins, minerals, other ingredients

Nutrient Requirements

• Requirements are derived from either modeling (factorial method) or titration study (empirical method) approaches
• Important factors:
  • Lysine level
  • Amino acid ratios
  • Phosphorous level in diet
  • Ca:P ratio

Resources for Requirements and Recommendations

• NRC (2012)
• National Swine Nutrition Guide
• KSU Swine Nutrition Guide (www.ksuswine.org)
• Genetic suppliers

General Nutrition Principles

• Sows
  • Gestation
  • Lactation
• Nursery pigs
• Finishing pigs
• Breeding Stock
  • Replacement gilts

Gestation Principles

• The main goal is to avoid sows being too fat or too thin
• Gestating sows have limited feeding
• Overfeeding gestating sows leads to:
  • Unnecessary expense
  • Impaired mammary development
  • Reduced feed intake in lactation
• Problems arise with thin sows:
  • Poor reproductive performance
  • Increased mortality
  • Welfare issues

Changes in Swine Farms Related to Gestation

• Individual vs. group housing
• How to effectively feed?

Lactation Principles

• First goal is to maximize lactation feed intake
  • Minimize loss of body condition
  • Maximize milk production for litter growth

Reaching Lactation Goals

• Avoid over conditioned sows at farrowing
• Provide ideal environment
  • Avoid heat stress for sow
  • Make sure warm enough for piglets
• Ensure adequate access to water
• Provide ad libitum access to feed

General Nutrition Principles: Nursery

• The goal is to get pigs off to good start, setting them up for efficient growth later in life
• Keys for success include:
  • Weaning good quality pigs
  • Maximizing feed intake after weaning
  • Providing proper management
  • Accommodating the biology of the pig
  • Adjusting to simple diets as quickly as possible

Example Nursery Diets

• Specialty protein sources are important in early diets
  • Blood plasma
  • Fish meal
  • Specialty soy protein
• Milk products are important in early diets
• Simpler diets are better as pigs get older
  • Corn, soybean meal-based

General Nutrition Principles: Finishing

• The main goal is optimizing formulation with production goals and economics
  • Feed cost per unit gain
  • Income over feed cost
  • Income over feed and facility cost
• Finishing pigs eat a lot of feed

Example Finishing Diets

• US Midwest diets often uses corn, soybean meal, DDGS-based diets.
• Grain and protein sources can vary depending on access to economical feed ingredients
• Finishing diets are generally quite simple; there are not a lot of different ingredients

Breeding Stock Principles

• Principles are similar to nursery and finishing pigs
• Longevity is very important
• Selection and feeding for structural soundness
  • Increased levels of Ca and P to maximize bone mineralization
• Lower amino acid +/- energy content compared to growing/finishing pigs to ensure gilts do not get too large before breeding
  • Increased maintenance feed requirements later in life
  • Increased structural stress/lameness/injuries
• Targets for 1st breeding: 200 days of age, 300 lbs body weight, at least 1 estrus cycle prior to first breeding

General Goals

• Breeding stock: longevity, prepare for productivity
• Gestation: body condition
• Lactation: maximize feed intake
• Early nursery: get pigs started on feed
• Late nursery, finishing: economics

Problems Encountered in Swine Nutrition

• Nutrient deficiencies/excess
  • Ca/P/Vit. D
  • Vit. E/Selenium
  • Iron
  • Cu/Zn/Selenium
• Gastric ulcer
• Post-wean diarrhea
• Mycotoxins

Nutrient Deficiency/Excess

• Calcium, Phosphorous, and Vitamin D
  • Balance is important and mistakes can lead to:
    • Fractures, weak/flexible bones (especially ribs)
    • Pathology of growth plates
  • Complex interaction can occur
    • Too much calcium reduces P uptake
    • Too little calcium results in poor mineralization
    • Too little Vit. D results in poor absorption and mineralization
  • Relatively wide range of phosphorous, calcium, and vitamin D levels are acceptable, but problems can happen
  • Work with nutritionist to ensure Ca/P/Vit. D levels are appropriate, and bone mineralization measurements like bone ash can be useful

Vitamin E/Selenium Deficiency

• Vitamin E has antioxidant properties
• Selenium is an important component of the antioxidant enzyme glutathione peroxidase
• Lack of vitamin E and/or selenium can result in increased oxidative stress and pathology such as Mulberry Heart Disease. Some cases of Mulberry Heart Disease are unassociated with dietary vitamin E or selenium
• Ensure that Vit. E/selenium levels are appropriate by working with nutritionist

Iron Deficiency

• Iron is important component of red blood cells (hemoglobin)
• Baby pigs very frequently become anemic if no iron is supplemented
  • Historically not as much of a problem if baby piglets had access to dirt
  • Modern production practices limit outdoor access due to biosecurity
• Baby pigs are routinely given iron injection in first 2-5 days of age (typically 200 mg iron in either dextran or gleptoferron form) -Some suggest another dose around weaning (3 weeks of age). Data is unclear, but generally 1-200 mg dose early in life is sufficient to avoid anemia

Mineral Excess

• Copper, Zinc, and Selenium are commonly added to swine diets in order to meet requirements and improve health, growth rates, and efficiency
• Excess can result in negative consequences
  • Harm to both animal and environment
• Work with nutritionist to evaluate Cu/Zn/Se levels

Example Mineral Feeding Levels

• A Zinc feeding program is common
  • There is pressure to reduce Zn usage in future
• Variability in Cu usage depending on cost/benefit and economics
• Maximum legal limit to supplement selenium is 0.3 ppm added Se to any swine in US

Gastric Ulcer

• Gastric ulceration (esophageal region, stratified squamous epithelium) is fairly common in swine
• 30 to 90% of pigs evaluated at harvest demonstrate histologic changes
• Lots of contributing factors: Particle size of diet, diet form (pelleted feed vs. mash), stress, recurrent feed outages, season, infectious agents
• Consider implications of particle size and diet form, keep feed in front of pigs at all times

Post-Weaning Diarrhea

• Diarrhea after weaning fairly common
• Contributing factors
  • Pathogens: E. coli, rotavirus, Salmonella, Coccidiosis
  • Host factors (genetic selection for E. coli resistance)
  • Environment: Sanitation, temperature, humidity, air flow
  • Diet

Post-Weaning Diarrhea (cont.)

• Common in young pigs
• Soybean meal causes hypersensitivity reaction in GI tract
  • Gradual increase in concentration as pig ages
• Excess undigested protein in hindgut contributes to excess fermentation and predisposes to diarrhea
• Using feed grade AA's (L-lysine, DL-methionine, L-threonine, etc.) allows AA needs to be met while reducing excess protein available for hindgut fermentation

Mycotoxins

• Can negatively affect the health outcomes of the swine
• Can come from a variety of sources

How to Investigate Problems

• Feed sampling and analysis procedures can be found online
• https://www.grains.k-state.edu/research/AnimalFeedandPetFood/feed_science_research_extension/quality_assurance_guidelines_resources/

Interpreting Feed Analysis

• Variability can come from feed manufacturing, feed sampling, and analytical variation. 15-25% is common.
• If results fall outside of the expected range, follow up with another sample
• Investigate further. Look into: Diet formulation error, feed manufacturing error, sampling error, and analytical variation

Interpreting Animal Measurements

• Little information is available for reference values for many nutrients (minerals/vitamins)
• What information is available is not current
• Blood and tissue samples not as useful as other diagnostic tests used in Veterinary Medicine

Nutrition Summary

• Don't be afraid of the nutritionist
• Swine nutrition is data driven
• Diagnostic testing is important component of swine medicine and swine nutrition
  • Know what the test is doing, know what appropriate reference ranges should be for your population of animals, recognize error in the sampling and analysis process
• Veterinarians play key roles in investigating nutrition issues
  • Feed formulation or manufacturing errors

Feed Safety

• It's an important part of swine agriculture

Feed Biosecurity Program

• A feed biosecurity program needs to consider ingredients, trucks (incoming ingredients & finished feed delivery), and people (moving between farms, entering feed mill)
• Ingredients: Are raw materials contaminated?
• There are examples of good feed biosecurity, which included ingredient receiving pit, truck disinfection, and inside mill best practices

Feed Safety Summary

• Understanding how ingredients come from, how they are handled, and how feed is manufactured and handled is major shift
• Veterinarians are involved!

Conclusion

• Topics covered, are just the basics
• Swine veterinarians often encounter problems where discussion regarding nutrition is warranted
• Feed safety is now a big priority

Resources

• www.ksuswine.org
• Nutrient Requirements of Swine, NRC 2012
• Nutrient Deficiencies and Excesses Chapter 68. 11th ed. Diseases of Swine
• Mineral Tolerance of Domestic Animals. NRC 2005
• Vitamin Tolerance of Animals. NRC 1987