Feeding Vitamin D3

Tenderness is one of the most critical attributes in determining consumer satisfaction with pork. Modern consumers demand pork that is not only lean but also tender. Unfortunately, fast lean growth genetics and meat tenderness are not necessarily positively correlated. After many years of selection for higher lean growth genetics, the incidences of tough pork products has been increasing. The challenge for the pork industry is to produce leaner pork without sacrificing tenderness.

The connection between calcium and meat tenderness has been well defined through research. Postmortem tenderization of meat products is the result of the activities of a family of calcium-dependent enzymes present in the muscle, known as calpains. The activity of calpains, which are controlled by the calcium concentration in the muscle cause the breakdown of muscle fibers resulting in more tender meat.

Vitamin D3 increases the amount of free calcium transported across the intestinal wall, which results in increased levels of free calcium in the bloodstream and muscle. The efficacy of feeding a high dosage of Vitamin D3 to increase postmortem muscle calcium and improve meat tenderness has been investigated in beef and lamb. Results demonstrated an improved tenderness in beef, but not in lamb.

Researchers at the University of Illinois and Iowa State University recently conducted studies to investigate whether feeding high levels of Vitamin D3 to pigs before slaughter improves pork tenderness. They found that feeding high dosages of Vitamin D3 to pigs for several days prior to slaughter might result in dark colored pork, which might be of higher value to Asian consumers. However, results from both studies failed to show positive effects on pork tenderness. Table 1 is a summary of the two studies.

Table 1. Summary of two studies investigating the effects of feeding high levels of Vitamin D3 prior to slaughter on pork tenderness and other pork quality traits

Illinois Study Iowa Study
Number of pigs (#) 36 24
Genetics Yorkshire x Duroc and Not specified
purebred Duroc pigs
Dosage of Vitamin D3 used (IU/kg of feed) 1) 331 200,000
2) 55,031
3) 176,000
Duration of Vitamin D3 Supplementation 10 days prior to slaughter 3 days prior to slaughter


Illinois Study

  • No tenderness improvement
  • Improved color and firmness scores in loin chops and reduced drip loss
  • Reduced feed intake and growth performance

Iowa Study

  • No tenderness improvement
  • Improved color
  • No detrimental effects on feed intake or other performance parameters


Wiegand B. R. et al. 2002. Short-term feeding of Vitamin D3 improves color but does not change tenderness of pork-loin chops.

J. Anim. Sci. 80:2116-2121.

Enright Kendra, et al. 1998. The influence of level of dietary Vitamin D3 supplementation and post-mortem aging time on pork quality.

Swanek S. S. et al. 1997. Effects of supplemental Vitamin D3 on meat tenderness.

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Author: Wayne Du - Pork Quality Assurance Program Lead/OMAFRA
Creation Date: 01 December 2002
Last Reviewed: 16 Febuary 2016