The changing of seasons may result in seasonal Vitamin D deficiency in sows,
according to research, which shows that supplementation of the “sunshine
vitamin” becomes especially important in
sow
performance as the hours of natural sunlight dwindle into winter.
According to Dennis Short, Ph.D., swine nutritionist for
Purina Animal Nutrition LLC, Vitamin D is one of the essential
vitamins in sow rations year-round. Though the typical requirement for this
micronutrient is only 0.004 pound of a vitamin D 500,000 International Units
(IU) per gram premix per ton of swine finishing feed, adequate levels are
necessary to promote herd health. As natural sunlight becomes less prevalent,
ration supplementation of Vitamin D becomes even more important.
“From October through February, we don’t see as much Vitamin D available to
the sow because of reduced photochemical conversion from the sun,” said Short.
In addition, UVB (ultraviolet B, which converts 7-dehydrocholesterol in the
animal’s skin to Vitamin D3) does not readily pass through glass for sows housed
indoors even if windows are present.
As a result, sows are more prone to Vitamin D deficiencies in the winter
months. Without proper levels of Vitamin D, sows can experience osteomalacia,
higher levels of lameness, decreased feed intake, reduced nutrient absorption
and produce lower quality colostrum. Meanwhile, pigs raised by Vitamin
D-deficient sows may have more significant levels of lameness and locomotive
disorders and a greater potential for hypocalcemia, rickets and mortality.
When it comes to locomotion issues, Short said he has seen numbers increase
steadily within the industry. In fact, the Iowa State University’s Veterinary
Diagnostic Laboratory saw 10 cases of metabolic bone disease in 2003. The number
grew to 40 in 2011. Mineral deficiencies may be a contributing factor to
increased levels of sow lameness.
“Many cases of metabolic bone disease are caused by low dietary mineral
levels,” said Short. “To prevent metabolic bone disease, sows must be fed a
mineral mix that provides the proper levels of calcium, phosphorous and Vitamin
D.”
Vitamin D is also a key driver of colostrum quality. Because pigs are born
with relatively low levels of the vitamin, high quality colostrum produced by
the sow can help the pigs better reach their full potential. “Colostrum is a
fairly rich source of Vitamin D,” said Short. “When we have larger litters, each
pig receives less colostrum and may experience lameness and/or health issues
later in life. Supplementing sows with Vitamin D can improve nutrient levels
provided to the pigs through colostrum and through lactation.”
Many industry groups and researchers have recognized the need for additional
attention to Vitamin D. The
National Research
Council of The National Academies recently increased their Vitamin D
requirement fourfold for gestating and lactating sows to 800 international units
per kilogram (IU/kg) (90 percent dry matter). When selecting vitamin and trace
mineral supplementation, Short said he encourages producers to work with a
nutritionist to create the proper combination and mixture of Vitamin D and other
essential vitamins.