There is an industry mantra that has existed since animal husbandry began: Healthy sows birth healthy piglets. There has also been a move to increase pigs per sow per year (PSY). With this as a success metric, are we pitting PSY against health? Today’s central question: How do we raise healthy sows and increase litter size?
Research tells us it’s not easy. Study after study indicates there are limits to a sow’s ability to produce the preferred large litters without it causing increased stress and strain, leading to weaker piglets and, ultimately, a less productive mother.
To be successful in today’s pork industry — with variables from disease challenges to market fluctuations — production efficiency is critical to keeping productivity high, which means management decisions become critical. Managing disease challenges, feed and water intake, introduction of new breeding stock and the myriad of environmental and management issues are all factors in sow, and her piglets’, health.
The Health Impact of Antibiotics & Vaccines
In 1951 the U.S. Food and Drug Administration bestowed on livestock farmers a new tool to fight animal diseases when it approved the use of antibiotics as feed additives. Pig farmers were quick to adopt therapeutics as a way to inhibit harmful bacteria, improve the efficiency of feed utilization and reduce farm waste. Producers have continued using the technology for decades.
At the turn of the millennium, a new consumer demand for pigs raised without antibiotics seemed to arrive, with some producers moving that way.
While the pigs raised without antibiotics designation may meet consumer demand, discontinuing antibiotic use in a sow means possible complications for her piglets as well. This will lead to more pathogen shedding and exposure to the piglets during lactation. While these may not be clinical during the pig’s early life, grow-finish consequences may become evident.
It is vital to ensure producers have taken steps to manage the many factors that can determine sow and piglet success. Production practices including employee training and management, a thorough evaluation of standard operating procedures through all three stages, and reviewing less thought-about practices such as ventilation, stocking density and water quality are all important health factors.
Preventative measures such as vaccinations and nutritional health products can offer additional disease defense. Michigan State University recommends a vigilant vaccine plan that includes:
- Vaccinating sows before farrowing to allow piglets the same virus protection through the mother’s colostrum. This has proven effective against leptospirosis, parvovirus, erysipelas and swine influenza virus (SIV).
- Administering other pre-farrowing vaccinations for rotavirus, E. coli and Mycoplasma hyopneumoniae, depending on herd health history.
- Following vaccination schedules recommended by veterinarians for piglets, boars and grow finishers.
Biosecurity, personnel and geography also matter. Before producers reduce antibiotic use or eliminate it altogether, they should make sure their biosecurity practices limit the introduction of pathogens, control pig flow to create uniform groups of pigs, provide separate housing for sick or injured pigs prior to treatment and segregate them from healthy pigs when marketing, and evaluate their operation’s risk for endemic bacteria disease, such as Strep suis, Mycoplasma hyorhinis and more.
Contract grower evaluation should include an emphasis on who can recognize clinical signs for disease threats before they become a problem, and are willing to put in the extra time that is required when raising pigs without antibiotics.
The health impact of food & water
“You are what you eat” holds as true for pigs as it does humans. It is vital that sows receive as much nutritional value from what they are fed, and at the right time, as possible.
Pigs consume 2-3 times more water than feed, especially in the sow herd. Water must be free of dirt and contaminants to meet these water intake levels. Water pipelines should be inspected and cleaned regularly to keep them free of yeast, mold and bacterial growth as part of regular barn maintenance. Use of water as a distribution for additional nutrition and even disease management should certainly be considered at the sow herd.
Adding a staff nutritionist who monitors feed quality and quantity can also maximize the health of both the sow and her piglets. Adding nutritional health products to improve gut health can also be a strategy to fight disease during highly stressful transition periods.
The health impact of breeding stock
Sick pigs make other pigs sick. About 90 percent of pathogens enter a farm through new animals introduced to the herd.
Swine specialists at Iowa State University recommend producers develop an animal introduction plan. Working with their veterinarian and genetics stock source, producers should examine their herds and source herds for endemic pathogens before adding new gilts. A priority on sow health will keep sows in the herd longer, as well as reduce the introduction of gilts. Not only do gilts tend to raise lower birth weight piglets, but they also may not have the colostrum and antibody support that sows offer.
The health impact of litter size
Equally as important as therapeutics, diet, reproduction and housing is litter size itself. When it comes to pigs per sow per year, larger litters and productivity are not necessarily synonymous terms. As the sow’s uterus has defined space limitation by their genetics, the more pigs that are conceived in the same amount of space, it stands to reason piglets will be smaller. Research indicates large litter piglets are not only more susceptible to low birth weights, but also susceptible to health problems and even early mortality.
A study by the Swedish University of Agricultural Sciences (SUAS) looked at litter sizes, frequency and health histories of 63,844 registered sows from 28 herds over a 17-year period. The sows were crossbred from combinations of Yorkshire, Landrace, Duroc and Hampshire sires.
The study produced some intriguing facts and figures:
- Sows that birthed a moderate number of piglets in the first parity litter were more likely to produce four or more litters during a lifetime, compared to sows with smaller or larger initial litters. Research indicated the ideal number of first litter piglets was 13.
- Except for a group of sows with first parity litters of 11 or fewer piglets in combination with a second parity litter of 12-14 piglets, all other sow groups exhibited a much higher failure to birth four or more litters in a lifetime.
- When aiming for a stillborn piglet average of less than six percent and mortality between birth and weaning of less than 14 percent, litter sizes should not exceed 13 piglets.
SUAS researchers concluded a direct correlation exists between litter sizes in low parities and sow retention and piglet health. The ideal litter size for both sow and piglets is 12-14.
A study by Scotland’s Rural College (SRUC) went further, examining welfare implications of large litter sizes.
Piglets from large litters were more prone to low birth weights, which led to poorer health, the SRUC reported. Teat competition among nursing piglets increases the likelihood that some do not receive milk, causing short-term malnourishment and long-term decline.
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