The Mare, the Foal-to-be and the Foal
Beneficial Bacteria and Yeast for the Pregnant and Lactating Mare
Larry Roth, Ph.D.
Proper care of the mare during gestation and lactation determines the health of the mare, current foal and the foal-to-be.
Improving diet utilization can aid the mare in meeting heavy nutrient demands, hormonal changes and immune system challenges during gestation and lactation.
A review of recent research suggests that beneficial bacteria, live yeast and yeast culture will be useful for mares during the gestation and lactation periods.
100 days and Counting
Nutrition for the pregnant mare is actually the feeding of two animals: the mare and developing foal. Over 50% of the fetus’ growth occurs during the final 100 days of the mare’s 340-day gestation period.
Inadequate nutrient intake by the mare during the final third of gestation can restrict fetal development and may result in the birth of a weak foal. The mare must be in proper body condition at foaling to withstand the rigors of giving birth, initiating lactation and, if desired, being prepared to conceive at the foal heat. A mare encountering an energy deficiency will ration its energy supplies on a priority basis to body maintenance first, lactation second and lastly to producing a future foal.
Colostrum, the first milk produced after foaling, is richer in proteins, minerals and vitamins than later milk.
The high protein content results from elevated levels of globulin and albumin.
These immune bodies are transferred from the mare’s blood to the milk and ingested by the new-born foal for disease resistance. The mare’s health status during the later stages of gestation will determine the amount and quality of colostrum produced for the new-born foal.
While the importance of the foal consuming colostrum is well recognized, the impact of nutrition on colostrum quality and quantity is less acknowledged.
The new-born foal is dependent upon the mare’s milk for nutrients for growth and support of the immune system. Although the lactating mare and cow are different animals, basic nutritional and physiological factors are applicable to both sets of mothers.
Milk quality and quantity are definitely impacted by the balance and quantity of nutrients consumed.
Proper supplementation of minerals and vitamins is the foundation for a good lactating mare program. A calcium deficient diet for the mare can result in poor skeletal growth by the nursing foal.
The mare’s intake of energy and protein will determine the energy and protein
content of the milk available to the foal.
Diseases contracted by the foal may determine its health and performance as an adult. The
milk will be the sole source of building blocks for the foal’s immune system. Hence the
importance of proper nutrition to the mare to ensure a fast start to the foal’s young life.
Maximizing Diet Utilization
After working with your veterinarian and nutritionist to select proper gestation and lactation
rations for your mares, it is time to maximize diet utilization. The small intestine is the
principle site of absorption for amino acids, vitamins, minerals and fats. Energy absorption
will occur in both the small and large intestines. Starch that is not digested and absorbed in
the small intestine will be fermented in the large intestine. Fiber from grazed and harvested
forages is fermented only in the large intestine. Some products of large intestinal
fermentation are absorbed and utilized as energy sources. However, excessive starch
fermentation results in digestive disorders, including colic.
Direct-fed Microbials or Probiotics
Scientists and horse owners are becoming acquainted with the opportunities to use direct-fed
microbial products, or probiotics, during the gestation and lactation periods of horses. Horse
owners have actually been enjoying the benefits of helpful bacteria and yeast for centuries.
Direct-fed microbials are species of beneficial bacteria and yeast reviewed by the Center for
Veterinary Medicine of the Food and Drug Administration and found to present no safety
concerns when used as direct-fed microbial products. It is important to note that these
products are not drugs and should not be viewed as such. Beneficial bacteria, including
Lactobacillus acidophilus and Enterococcus faecium, are preserved by freeze-drying and fed
as live, viable microorganisms. Yeast products available to the horse owner include active dry
yeast and yeast culture. Active dry yeast products feature live yeast cells dried to maintain a
large portion of their fermenting capability. Yeast culture products are composed of the yeast
cells and the yeast’s growth media; and the products are dried to preserve some of the
yeast’s fermentation capabilities (Assoc. of American Feed control Officials).
Research documents the ability of the beneficial bacteria Lactobacillus acidophilus and
Enterococcus faecium to attach to the lining of the small intestine to enhance nutrient
absorption. Nutrient absorption is a major energy expenditure by the animal. Studies
indicate that the binding of beneficial bacteria to the intestinal lining reduces the energy costs
associated with nutrient absorption. Consequently, more energy would be available to the
animal. Therefore, supplementing beneficial bacteria to the gestating or lactating mare could
potentially increase nutrient absorption while lowering the energy expended. Attachment to
the small intestine lining also reduces the opportunities for harmful bacteria, such as E. coli or
Salmonella to adhere and increase in number.
Yeast and Yeast Culture
Several studies, notably by Glades and coworkers, have demonstrated improved milk quality
and quantity by mares supplemented with yeast products, and consequently improved foal
growth. The yeast products supply enzymes, B-vitamins and other factors to stimulate
beneficial bacteria in the small and large intestine. Enhancing fiber fermentation increases
energy availability to the mare for gestation or lactation needs. In addition, increasing the
amount of energy derived from forages could allow a reduction in the amount of grain fed.
Lowering the grain content of the ration could potentially reduce the risks of digestive upsets.
However, any decisions concerning the level of grain feeding should be based on body
condition and anticipated animal requirements.
Easy to Use
Direct-fed microbial products are available as dry powders to be simply mixed in the feed or
top-dressed on a once daily basis. An off-feed horse can receive the direct-fed microbials via
gel or paste products placed directly in the horse’s mouth. The direct-fed microbial products
should be stored at room temperature or refrigerated if possible to maintain viability. The
beneficial microorganisms are alive and become more active with elevated temperatures.
However, the "warmed-up and active" desirable bacteria and yeast eventually deplete their
energy reserves and die. Proper storage and handling of the direct-fed microbial products
will allow your horses to fully realize the potential benefits.
Horse owners have been providing beneficial bacteria and yeast to their animals and
enjoying the results unknowingly for many centuries. Understanding the nutritional needs of
gestating and lactating mares highlights many opportunities for direct-fed microbial product
usage. Research studies indicate that direct-fed microbial products can aid gestating and
lactating in maximizing diet utilization for producing healthy and active foals.
Larry Roth, Ph.D. is a Research Scientist with Conklin Co. Inc. 551 Valley Park Drive, Shakopee, MN 55379.
Dr. Roth conducts research on the benefits of direct-fed microbial products with food-producing and companion animals, as well as writes and speaks in the U.S. and internationally on the topic. Questions can be forwarded to Dr. Roth at Conklin Co. Inc.