Tools such as pig flow, vaccines and biosecurity may play a more important role in herd health than diet, but every little bit helps.
Fact is, diet can and does influence herd health. Specifically, some dietary additions can help combat enteric disease. Since those diseases are a larger problem for newly weaned pigs than in other production phases, the options presented here by Jim Pettigrew, University of Illinois swine nutritionist, will address nursery diets.
In designing weaned-pig diets, ingredient choice is important because it influences palatability, intake, digestibility, as well as the type and amount of substrate available for microbial fermentation in the pig’s gastro-intestinal tract.
Some ingredients reduce microbial growth and therefore help to control enteric diseases. “Even if enteric diseases are not a major problem in your herd, you could benefit from the growth response certain feed ingredients can give,” says Pettigrew. He points to in-fed antibiotics and organic acids as examples.
A high dietary concentration of proteins has been shown to predispose pigs to post-weaning Colibacillosis. But, Pettigrew says more research is needed to confirm the connection.
Fermented liquid feeding is one dietary strategy to fight enteric disease. Fermented feed contains high concentrations of lactic acid, volatile fatty acids and large numbers of Lactobacilli. Fermented liquid feeding has been shown to help prevent diarrhea, such as swine dysentery. This may occur by reducing the number of Coliform bacteria and Brachyspira hyodysenteriae in the gastro-intestinal tract of young pigs and growing pigs, notes Pettigrew.
Still, there are many other feed ingredients that can contribute to herd health. Some are still in the experimental stage, notes Pettigrew.
Antimicrobials. It is presumed that the benefits of antimicrobials, derived partially from their ability to reduce or inhibit microbial pathogens in the digestive tract, cause a shift from pathogenic to commensal bacteria. The result is enhanced nutrient uptake and reduced nutrient utilization by the thinner intestinal walls, there’s less substrate available to proliferate pathogenic micro-organisms, and therefore the health and integrity of the digestive tract improves.
Cereals. Corn is the predominant energy source in U.S. swine diets. But in other parts of the world cereals, such as barley, sorghum, wheat and rice are more available and less expensive. Diets containing high-levels of non-starch polysaccharides contained in certain cereals may increase diarrhea susceptibility.
Non-starch polysaccharides found in cereals are part of the dietary fiber in swine diets and are important energy substrates for microbial fermentation. Feeding different levels and types of non-starch polysaccharides to young pigs could manipulate the composition and activity of the microbiota in the pigs’ large intestines, and affect the incidence and severity of enteric diseases.
Spray-dried plasma. Research shows that adding spray-dried plasma to weaned-pig diets can improve growth by 26.6 percent and average daily feed intake by 24.5 percent in the first two weeks after weaning.
In addition, spray-dried plasma may help control post-weaning diarrhea associated with changes in the intestine’s flora, function and morphology. Spray-dried plasma may be most beneficial under conditions where pigs face high pathogen levels.
Milk products. Adding lactose to the diet for a few weeks after weaning improves piglets’ growth performance. Research shows there is no effect of lactose on the number of Lactobacilli adhering to the wall of the digestive tract. However, the method in which the milk product was processed may have an impact on the pigs’ performance. More research is needed.
Organic Acids. Adding organic acids to the nursery diet may have positive and negative effects. Adding high concentrations of organic acids to a diet can reduce the pH to 5.0, which can help control Salmonella and other pathogens that may be present in the feed.
On the negative side, high organic acid levels can reduce a feed’s palatability, causing the pig to refuse to eat. Acidic feed also is more corrosive to cement and galvanized steel.
Common organic acids include citric acid, formic acid, potassium diformate and lactic acid.
Direct-Fed Microbials. These are defined as live-microbial feed supplements, which benefit the host animal by improving its intestinal microbial balance. Bifdobacteria have been reported to reduce or prevent diarrhea by suppressing pathogenic bacterial colonization in the intestinal tract. Bacteria such as Bacillus cereus, Brevibacterium lactofermentum, Lactobacillus casei, Bacillus cereus, Lactobacillus spp., Bacillus toyoi and Bacillus licheniformis also decreased the incidence and severity of diarrhea in pigs.
Yeast culture is another direct-fed microbial for the nursery pig diet. Live-yeast supplementation has resulted in improved growth rate and has reduced diarrhea occurrence. However, Pettigrew says that most studies have reported no improvement in performance of nursery pigs fed a yeast-supplemented diet.
Prebiotics. A prebiotic is a non-digestible ingredient that benefits the host by selectively stimulating the growth and/or activity of one or more bacteria in the colon. These non-viable dietary components fortify certain intestinal flora. The metabolic end products may lower the intestinal pH to levels below which pathogens are able to effectively compete. The inclusion of offructooligosaccharides, a type of prebiotic, in the diet has been shown to influence the degree and severity of diarrhea in nursery pigs.
Trace Minerals. Copper may alter the microbial populations within the pig’s gastro-intestinal tract. Growth rate and feed-efficiency responses in nursery pigs to high dietary copper are similar in magnitude to those from antibiotics. In a summary of 23 studies conducted at the University of Kentucky, an 11.9 percent improvement in growth rate and a 4.5 percent improvement in feed efficiency occurred with copper supplementation. Studies show the inclusion of 2,000, 3,000 or 6,000 parts per million of zinc from zinc oxide can improve nursery pigs’ growth performance and reduce the incidence and severity of diarrhea.
Plant Extracts. Some plant extracts, including essential oils, herbs and spices are known to contain compounds with antimicrobial effects. The extracts can prevent bacterial replication or kill bacteria. Some extracts increase the diet’s aroma and taste, which can enhance feed intake.
Enzymes. Enzyme supplementation can help the animal digest proteins, fats and carbohydrates. They let the pig absorb nutrients for its own use rather than letting them enter the large intestine as a nutrient source for its microbial inhabitants. Some research has shown improved feed efficiency and reduced diarrhea in nursery pigs fed a barley/wheat or barley/wheat/corn diet supplemented with cellulase, beta-glucanase, amylase and glucoamylase.
Selecting feed ingredients or trying new ones, is an individual choice.
“The ingredients I have the most confidence in are spray-dried plasma and milk products,” says Pettigrew. No question, much more research needs to be done in this area.
Pettigrew adds that economics are driven by effectiveness, so he contends that spray-dried plasma and milk products are the most economical, although they may not be the cheapest.
“You don’t need to have a big problem with enteric disease to try products like spray-dried plasma or milk products,” says Pettigrew. “Producers whose pigs have enteric disease problems are more likely to look at other alternatives, but you can usually get a growth response with some of these products.”
Ultimately, any product that saves pigs and has a growth benefit in your herd should be profitable in the long run. If they reduce enteric diseases in the nursery, the pig savings and growth will follow.