GILTS represent the future of the sow herd and make up close to 25% of the U.S. swine population; however, the importance of gilt development to the sow's lifetime contribution to the herd is often underestimated.
Because gilts represent the newest genetic pool, focusing on gilt nutrition and development can help producers move forward quickly.
Gilt development begins after pigs exit the nursery. Industry data suggest that gilts should be fed for production once they reach 150-180 lb. Field demonstrations in both the U.S. and Spain suggest that swine producers need to begin gilt development for replacement gilts at an even earlier age than the current thinking.
Starting these females out on the right nutrients and correct growth rate level is important to maximize their lifetime potential and longevity within the herd, according to an announcement from the "Feeding for 30" program.
"Gilt retention rates can be improved by up to 50% within the sow herd by implementing some simple changes, such as providing larger pen space per pig, utilizing better flooring and feeding a balanced diet — one that includes zinc, manganese and copper as amino acid complexes," Dr. Mark Wilson, a reproductive physiologist at Zinpro Corp., said.
Without adequate space, environments and nutrition, gilts may have a greater potential for lameness. Structural issues on the feet and legs can put gilts at a disadvantage from the start with lower reproductive rates, decreased feed consumption and depressed joint, muscle and skeletal development. In fact, lameness accounts for an estimated 15% of total culls through the first parity.
One of the keys to helping gilts develop structurally is improved nutrition. Addressing the growing gilt's nutritional needs not only decreases feed costs but also contributes to her longevity in the herd.
Wilson encouraged producers to start developing their replacement gilts as early as 40 lb. of bodyweight in order to maximize their lifetime potential and longevity in the herd. By slightly slowing her growth rate and feeding correct levels of essential nutrients, she is able to reach physiological maturity at 230 days of age and 300 lb. of bodyweight with an improved skeletal structure-to-weight balance.
Bringing mature, structurally sound gilts into the herd improves their chances of reaching their fourth parity — the point at which they begin making money for the swine operation. In fact, data show that increasing the number of sows in parities 3-6 has a significant effect on the overall productivity of the herd.
The weight of a gilt at breeding can be a contributing factor to lifetime productivity as well. Research has shown that by breeding gilts at 300-310 lb. of bodyweight on their second or third estrus, the gilt has the weight and maturity to gestate and support a litter of pigs and is much easier to re-breed after the first litter. Gilts bred at less than 300 lb. had fewer total pigs over three parities than their heavier, more mature counterparts, as shown by several different genetic groups.
"Nutrition plays an essential role in gilt development programs to help prepare young sows to meet the challenges of their first parity," Wilson said. "Ultimately, this sets the stage for improved animal performance and sow longevity."
The Feeding for 30 program is an industry-wide initiative that serves to help the U.S. swine industry move toward 30 pigs per sow per year by sharing sow nutrition and management research. The program is led by Purina Animal Nutrition, in partnership with Zinpro and DSM Nutritional Products.
Cold temperatures can be problematic to long-term sow performance if not accounted for, but changes can be made before temperatures drop too low and sows are affected.
Two strategies for mitigating cold stress are facility air movement and adjustments in sow rations.
Industry research shows that cold temperatures can cause sows to lose body condition, which, in turn, can affect fertility, milk production and piglet survival and growth performance — resulting in potential declines in sow longevity and parity structure in the herd.
Dr. Vern Pearson, a swine nutritionist for Purina Animal Nutrition, recommended evaluating air temperature, air flow and sow rations in the facility to reduce the risk for cold stress in sows.
Air flow and temperature. Recommended seasonal facility changes vary based on the type of facility.
Pearson said air temperature is not usually a severe challenge in curtain-sided or environmentally controlled gestation and farrowing barns, but air flow can cause concerns.
"In these facilities, adult sows typically provide enough heat to warm the barn," he said. "We need to evaluate mechanical ventilation, however. Be sure that mechanical ventilation, which is needed for air flow in the summer, does not create excessive air movement that could cause a 'wind chill' effect inside climate-controlled barns."
Both air temperature and air flow can be problematic in open-fronted and open-sided barns used to house sows. In these settings, additional bedding and management of drafts can help minimize chilling of animals.
Cold-weather sow rations. Pearson said the most common effect of cold temperature stress is that sows do not consume enough feed in the winter to maintain their condition. Decreases in body condition score (BCS) below the ideal score of three on a five-point scale can set sows back in long-term performance.
"We need to keep sows at a BCS of three, which may require more feed during cold temperatures," he said. "As temperatures decrease, sows require more feed to regulate their cold body temperatures. Without added nutrients, the sow will allocate resources away from other body functions."
In addition to body condition maintenance and litter support, sows require energy to generate internal heat during cold periods. Pearson said researchers at Mississippi State University Extension estimate that sows require up to 25% more feed during extremely cold conditions.
Tips to help maintain consumption levels and meet this higher nutrient level include:
* Provide fresh feed several times throughout the day to account for the sows' instinct to consume more during cold spells.
* Increase the content of high-fiber ingredients such as oats, barley, beet pulp, wheat bran, dried distillers grains plus solubles, alfalfa meal and soybean hulls. The bulk of these materials can help increase the amount of heat produced by the sow for digestion, slow the ration passage rate, dilute the energy concentration of the ration and, often, reduce overall ration costs.
* Add fat to the ration to increase energy levels, based on the age, stage of gestation and BCS of the sows.
* Feed according to the stage of production. Generally, first-litter gilts have greater nutritional needs as they grow to their mature size. Late-gestation and lactating sows of all ages need more energy to support birth and weaning weights and milk production. Thin sows need additional energy to withstand cold conditions without sacrificing additional body condition.
* Ensure that sows have access to fresh, unfrozen water at all times. Water helps regulate body temperature and can affect feed intake; determine a backup system for heated water to account for power outages or frozen water lines.
"It's a combination of management factors that helps sows thrive through winter," Pearson said. "The correct combination of ration adjustments as well as air temperature and air flow management can help producers set sows up to perform long term through the cold season."
According to AB Vista research manager Dr. Helen Masey O'Neill, until a definitive study is published to show that all components within a multi-enzyme product are necessary for optimum benefit, there is no evidence to justify their use over an optimized single-component non-starch polysaccharide (NSP) enzyme.
Masey O'Neill's statement was made in a paper published recently in the Asian-Australasian Journal of Animal Science reviewing the mechanisms by which fiber-degrading feed enzymes can improve animal performance when added to monogastric diets. The problems associated with the fibrous NSPs in plant-based feed ingredients — increased digesta viscosity, wet litter, reduced nutrient utilization, etc. — are widely known, but the optimum strategy for tackling them is less well understood.
"The challenge is that the literature advocating multi-enzyme dosing is based on studies which are incomplete, inadequately designed to support the conclusions made or both," Masey O'Neill said. "In products claiming multiple activities, it is impossible to assign results to a particular enzyme or enzyme combination unless a complete analysis of each individual component is carried out separately and all the various permutations of two or more enzymes are also assessed.
"Practically, this is difficult to achieve, yet without it, there is no clear evidence that the extra activities are producing any additional benefit beyond that achieved by an optimized dose of an appropriately targeted single enzyme," she added.
In one published evaluation, a purified xylanase extracted from the multi-enzyme product being studied was less than 30% stable at the pH found in the gut, compared to 70% stability for the crude product. Failing to compare "like-with-like" means that any performance difference cannot be attributed to the additional enzyme activities present, Masey O'Neill said.
"Caution needs to be applied when interpreting such data. There is currently no robust evidence showing whether additional activities are beneficial, superfluous or even detrimental, and in the many comparisons carried out to date, it is not usually the enzyme product with the greatest number of activities that results in the best performance," she added.
A full, open-access version of the paper is available at www.ajas.info/Editor/manuscript/upload/AJAS_Feb2014_27_290.pdf.
Although water consumption is an important indicator of a swine herd's performance and health, water may be the most overlooked nutrient for a pig, according to South Dakota State University Extension swine specialist Bob Thaler.
"When thinking about the pig's nutrient requirements, it is easy to focus on common things like amino acids, metabolizable energy, vitamins and minerals. However, water is the nutrient that the pig consumes the most of during its life. It is probably the most mismanaged, and unfortunately, it is also the nutrient that has the least amount of research done on it," Thaler said.
What little research has been done is confounded by the different types of watering devices used, Thaler said.
"Feed intake and, subsequently, growth performance are strongly correlated with water intake, so anything that decreases or inhibits water intake will result in reduced pig performance," he said.
How much water does a pig need for normal growth? Daily water requirements depend on the phase of production, and recommendations are as follows:
* Newly weaned pigs need 0.5 gal. per pig per day;
* Grow/finish pigs need 1.5 gal. per pig per day;
* Gestating sows and boars need 4.0 gal. per pig per day, and
* Lactating sows need 6.0 gal. per pig per day.
Thaler said it is very important to realize that these numbers represent how much water a pig needs to drink. They do not include the amount of water needed for cleaning, cooling, etc., which can account for approximately 28% of the water used in a facility.
Thaler noted that research shows that pigs have a pattern by which they drink water throughout the day. When using nipple waterers, finishing pigs and gestating sows drink the most water between 3 p.m. and 9 p.m. and have a smaller peak between 5 a.m. and 11 a.m. Nursery pigs consume the most water between 8:30 a.m. and 5 p.m., and lactating sows consume water throughout the whole day since they are producing milk throughout the day as well.
"What makes this information important is hog producers need to have enough watering devices available at those peak times of water consumption so all pigs can drink all they want during those high-demand times," Thaler said.
It is recommended to have two functional nipple waterers if there are more than 10 nursery pigs in a pen or more than 15 finishing pigs in a pen. Nipple waterers can become plugged with rust, sediment, minerals, etc., over time, so Thaler said it is critical to check each nipple daily to make sure it is working properly.
Nipple waterers must also be placed at the proper height to maximize water intake. A general rule of thumb is to adjust the nipple height to be equal in height to the pig's shoulder.
"If the waterer is too low, the pig will still work to drink water, but it won't drink all it wants, so feed intake and performance will suffer. This is especially important for lactating sows," he said.
Another critical factor to adequate water consumption, Thaler pointed out, is the water flow rate as it leaves the waterer.
"Too little or too much water flow/pressure will decrease water intake, so it is essential to adjust all waterers to provide the proper flow rate," he said.
Recommendations for flow rates are: 250-500 mL (one to two cups) per minute for nursery pigs; 500-1,000 mL (two to four cups) per minute for grow/finish hogs, and 1,000 mL (four cups) per minute for breeding animals.
"Water consumption not only affects growth performance, but it also can be an indicator of health status," Thaler said.
For example, if a barn is showing three consecutive days of decreased water intake or a 30% decrease in water consumption in one day, that is a good sign of a potential health issue occurring in the barns, and Thaler said barn personnel need to manage the issue accordingly.
"Water is a critical nutrient that is often overlooked, and it has a dramatic impact on every phase of pork production. It needs to be provided in the proper amount and pressure and in a way easily accessible to the pig," Thaler said.