Lactating Swine Nutrient Recommendations and Feeding Management
Many factors influence sow productive efficiency and sow herd profitability, but inadequate feeding programs for the sow are major contributors to problems with high sow attrition and poor productivity. The primary challenge of feeding highly productive sows involves minimizing the negative nutrient (energy and protein) balance during lactation in order to minimize short-term and long-term reproductive performance problems. The lactating sow needs energy and nutrients to maintain body tissues and support milk production, while allowing for maternal growth. Excessive negative nutrient balance during lactation can be minimized by increasing sows feed intake or, to a lesser extent, increasing nutrient concentrations of the diet. Understanding the different factors that affect nutrient requirements and feed intake can assist in developing a successful lactating sow feeding program.
The objective of the feeding program for lactating sows is to:
- Ensure that all sows consume sufficient feed on a daily basis to meet their energy and nutrient requirements
- Minimize short- and long-term reproductive performance problems due to negative energy and nutrient balance.
- Optimize litter performance
Factors Affecting Nutrient Requirements
The main objective for nutrition of the lactating sow is to minimize negative nutrient balance while optimizing milk production. Modern sows produce large volumes of milk, up to 3 gallons (or 25 lbs) per day. Relative to her body weight, a good sow produces more milk than a dairy cow. This high level of milk production results in daily nutrient requirements that are about three times higher than during gestation.
The energy and nutrient requirements of the lactating sow depend upon her weight, milk yield and composition, and to a lesser extent, the environmental conditions under which she is housed (1). For highly prolific and productive sows, nutrients from body tissue reserves and feed are used to support lactation. This often results in loss of body weight (negative nutrient balance). Excessive body weight loss can lead to short-term reproductive problems such as extended wean-to-estrus interval and smaller subsequent litter size. Long-term problems include a high culling rate of the sow herd resulting in low average parity, reduced pigs weaned per reproductive lifetime and higher genetic cost per pig produced.
Lactation is the most demanding phase of the reproductive cycle, with significant energy being required for milk production. Daily energy needs for lactation include energy needs for maintenance and milk production, and these needs will often exceed energy intake for at least part of the lactation period. If dietary energy intake is not sufficient to meet these demands, body tissue will be mobilized to provide nutrients for milk production, primarily from fat stores. Additionally, genetically leaner sows may not have fat stores to mobilize and therefore may catablize body protein. If extensive catabolism takes place, this is detrimental to short and long term sow productivity.
The energy and nutrient requirements for milk production are directly related to litter growth rate, and can therefore be estimated from growth rate of the suckling pig and number of pigs nursing (2). Likewise, the energy and nutrient requirements for maintenance of body tissues in the lactating sow is directly related to sow body weight. Therefore, by measuring or estimating these two parameters, one can accurately assess daily nutrient requirements. In practical situations, it may be difficult to individually feed sows based on specific sow and litter production parameters. However, any steps that an be taken to match nutrient intake to production performance will maximize efficiency of nutrient utilization while meeting requirements.
Maximizing Feed Intake
Negative nutrient balance can be minimized primarily by increasing feed intake and secondarily by increasing nutrient concentration in the diet. Higher feed intakes during lactation increase blood insulin and luteinizing hormone (LH) levels, leading to a greater number of follicles produced in the ovary. This in turn can lead to a larger litter size on the subsequent farrowing. Maximizing feed intake during lactation is critical to improve overall sow performance including productivity and longevity. There are a number of different factors that affect feed intake:
Lactating sow feed intake increases from the first to the sixth parity, with the majority of increase from first to second parity (15 – 20%)(1). Sow lactation feed intake often is not enough during lactation to meet the sow’s energy and nutrient needs for maintenance and milk production, especially for parity 1 and 2 sows. These sows subsequently mobilize their own body tissues to meet their energy and nutrient needs. Research has shown that if these first and second parity sows mobilize more than 15% of their protein mass during lactation, thus reducing subsequent reproductive efficiency and litter weaning weight (3,4). Additionally, first parity sows are still growing and thus may have lower body stores of fat, protein and minerals to draw from. Limiting litter size in first parity sows to 10 pigs and segregated lactation feeding of these sows compared to multiparous sows can provide assistance in minimizing the second parity slump in reproductive and litter performance that is sometimes observed in herds.
Condition of sow entering farrowing
Overfeeding during gestation reduces feed intake during lactation. Several studies have demonstrated that as feed intake and the associated weight gain during gestation increase, feed intake during the subsequent lactation decreases (5,6). Sow longevity is also negatively affected by increased gestational body weight gain and fatness (7), while excessive energy intake can compromise mammary development during gestation and may reduce milk production in the subsequent lactation (8). Sows should be fed during pregnancy to achieve a body condition score of 3 on a 5 point scale at the time of farrowing, or approximately 0.7 – 0.8 inches last rib backfat (Figure 1). Feeding sows during gestation based on body weight and backfat level will greatly increase the proportion of sows in optimal body condition entering farrowing (9). More information on appropriate feeding strategies for sows during gestation to achieve ideal body condition at farrowing is provided in PIG Factsheet #07-01-11 (Gestating Swine Nutrient Recommendations and Feeding Management).
Level of dietary protein
The level of dietary protein has also been shown to affect amount of feed consumed by the sow during lactation. In one study (10), decreasing the crude protein level of the diet from 16% or 18% to 12% or 14% resulted in reduced feed consumption, and consequently increased weight loss in sows over the lactation period. Additionally, piglet weaning weights were lower. If lower protein diets are not appropriately formulated to ensure essential amino acid requirements are met, increased delays in subsequent wean-toestrus period and poorer conception rates may occur, particularly in first parity sows (11).
Feed multiple times per day, keep feed fresh
It is generally recommended and accepted that feeding lactating sows two or more times a day versus single feeding will result in increased feed intake and thus improved reproductive and litter performance. Research investigating multiple versus single feeding regimens during lactation, however, have not demonstrated considerable differences in daily and overall lactation feed intake (12). Feeding multiple times daily increases number of observations of the sow and litter, freshness of the feed provided, and also offers the ability to more frequently remove wet or spoiled feed from feeders, and therefore its importance should not be minimized. It is quite likely that the environmental and management conditions under which university research trials have previously been conducted may have precluded observing increases in feed intake due to multiple feedings, whereas less desirable conditions in commercial production would likely result in such increases. Practical experience on farm has demonstrated that feeding multiple times daily increases overall lactation feed intake and piglet and litter weaning weight, as well as reduces wean to estrus intervals. It is our recommendation that sows be fed at least twice, but preferably three or four times, daily to increase observation times and drive maximal feed intake levels in lactating sows.
Diet form and feeder design
There appears to be no appreciable improvement in litter weight gain, sow feed intake, or sow weight loss by feeding pelleted diets compared to ground mash diets (13). If feed wastage is appreciable with mash diets, pelleting may reduce the amount of feed waste, but it may be more appropriate to evaluate the feeder itself and determine if adequate area and design allow the sow easy and complete access to the feed. Feeders that are improperly designed may restrict the sows ability to consume maximal levels of feed. Bars, rods, or other types of items in feeders tend to restrict access and should be avoided – feeders that are larger and provide open access to the feed pan are preferred. Average particle size of grain in sow diets of 700 microns provides optimum sow performance, feed processing efficiency and feed flowability while minimizing ulcer issues.
Feeding wet feed versus dry feed has been shown to increase feed consumption 10 – 15% (14). Although it may be impractical for many producers to convert their entire operation to a wet feeding system, simply mounting a water nipple in the farrowing crate directly over the feed hopper can help increase feed intake. However, additional feeder management is required so that wet feed does is fresh and does not accumulate and spoil.
Use of ad-libitum feeders for lactation, when properly managed, can increase feed intake also and thus minimize body weight loss during lactation. These feeders ensure feed is always present when the sows want it, and if feed is kept fresh, will enhance feed intake in sows, allowing then to increase feed intake levels sooner after farrowing while increasing total lactation feed intake. More recently, research has shown that using a self-fed wet/dry feeding system in lactation, in which sows are able to choose when and how much feed to eat and amount of water to be mixed with dry feed when dropped into the feeder, enhances sow appetite, improves litter growth performance, and wastes less water compared to a traditional hand-fed dry feeding system with separate waterer (15). Regardless of feeding system, emphasis should be placed on feeding sows at ad libitum levels as soon as possible in lactation.
Restricted access to water (either from inadequate location of supply or insufficient flow rate) can reduce feed intake and thus decrease sow and litter performance during lactation. A lactating sow can consume upwards of seven gallons of water a day. A water flow rate of 1.5 – 2 pints per minute should be adequate ( a 16 oz soda bottle is one pint). However, many water nipple drinkers in farrowing crates do not supply adequate quantities of water, and therefore flow rates need to be checked periodically.
A high temperature in the farrowing room will depress appetite in lactating sows. Younger first and second parity sows, which tend to be lighter eaters, and extremely large or overweight sows tend to be more negatively affected by high temperatures. Therefore, it is important to keep the farrowing room temperature between 65 and 70 degrees F, where sow comfort is maintained, and use supplemental heat and minimize drafts to keep piglets from becoming chilled. As a rule of thumb, average daily sow feed intake decreases 0.2 lb for every degree F above 66 degrees F (14,16).
Use of a water drip system can increase sow feed intake by as much as 25 – 50% or more during hot weather. Snout coolers can also provide heat relief to the sow, although not as substantial as water drip (17). Flooring type will also greatly affect ability of the sow to dissipate heat.
Wetting lactation sow feed at the time of feeding can also increase intake during hot weather by about 2 lb/sow/d (14) but requires extra time and attention, both for wetting the feed and also cleaning up uneaten feed. Perhaps more practical is ensuring that sows have feed available over the late evening and nighttime periods, when temperatures are cooler and lactating sows will consume 20-25% more (18).
Adequate lighting in the farrowing room is necessary to allow satisfactory observation of the sow and litter, but exposure to lighting also appears to influence feed intake in sows. Research has suggested that exposing sows to 16 hours of light per day in the farrowing room compared to 8 hours or less increased sow feed intake and litter weaning weights while improving rebreeding performance (19, 20).
The appetite of the lactating sow is lowest immediately after farrowing, increasing gradually up to the third week of lactation. It is well accepted that maximizing feed intake during the lactation period is imperative and should be a primary goal of the feeding system. However, many farms choose to provide a feeding program that gradually increases feed allowance to sows over their first 5 – 7 days post-farrowing before feeding at an ad libitum level. Compared to more aggressive feeding systems that challenge the sow with full feeding levels within the first day or two after farrowing, these restricted feeding systems reduce sow feed intake by up to 15% the first week of lactation. Sows do not compensate for low feeding levels the first week post-farrowing by eating more later in lactation, and therefore will lose more body weight and wean lighter pigs as a result.
The fear of causing udder congestion, reducing milk production, piglet scours, sow constipation, and having sows go off feed during mid lactation by ‘overfeeding’ drives this practice. However, data indicates that 10 – 30% of all sows exhibit a dip in feed intake for 2-3 days in the second week of lactation, irrespective of early feeding level (21). The cause of this dip in feed intake is not well understood, but is not necessarily due to higher initial feed intake. It is known, however, that restricting feed intake in any week of lactation, whether imposed or due to a poor appetite, will increase sow weight loss and can reduce reproductive efficiency. (16,21). Farms that use a gradual increase in feeding program during early lactation have lower litter weaning weights and longer wean-to-estrus intervals compared to farms using a rapid increase in early lactation feed intake. This emphasizes the importance of maximizing feed intake as soon as possible following farrowing and throughout lactation in order to limit sow body weight loss, maximize piglet growth rate, and optimize subsequent reproductive performance.
In general, lactation diets for highly productive sows should contain ingredients that are concentrated sources of energy and protein such as corn and soybean meal. Feed ingredients that are high in fiber content, such as soy hulls, oats, wheat midds, beet pulp, alfalfa hay, or wheat bran dilute the nutrient content of the diet and may limit total nutrient intake. Some producers add bulky feed ingredients to the sow’s diet before and a few days after farrowing in an attempt to prevent constipation, reduce incidence of mastitis, and prevent death loss due to twisted gut, but research indicating improvements in sow performance by adding laxatives or bulking agents to lactation diets is lacking. Bulking agents may improve sow comfort and produce a softer stool if added to prefarrowing diets.
Supplemental fat can be added to lactation diets in an effort to increase energy intake of sows. Increasing caloric density of the diet when sow feed intakes are insufficient to meet energy needs, particularly during hot weather, may at least partially make up this deficiency in energy intake. Additionally, the heat increment of the diet (amount of heat produced when feed is digested and metabolized in the animal) is reduced when increased energy comes from fat or oil sources versus carbohydrates. While supplemental fat may reduce weight loss and backfat loss in lactating sows, it is primarily used to increase daily gain of nursing piglets. Since the sow transfers dietary fat to milkfat, the calorie intake of nursery pigs is increased, thus weaning weights are improved (23). However, there are practical limits to this process. Supplemental fat increases diet cost. Addition of fat above 5% increases the risk of feed becoming rancid if a preservative is not used and causes bridging and caking of feed in feeders and bulk bins.
Calculating Feed Intake
In order to be able to accurately determine what nutrient concentrations should be provided in lactation sow diets, actual feed intake level needs to be determined. Average feed intake values for the sow herd can be most accurately calculated by analyzing feed deliveries over a period of four to six months. Two calculations are most helpful for determining actual lactation feed intake. The first method uses crate days and feed delivery to estimate feed disappearance per sow per day, but tends to underestimate actual sow feed intake levels because it does not compensate for days crates are empty or contain prefarrowed sows that are eating lactation feed. The second calculation utilizes number of farrowings and lactation length, and tends to overestimate actual intake because feed for sows in farrowing crates prior to farrowing is counted as feed to lactating sows. Therefore, the average of these 2 methods should be used as the estimated feed intake.
Tracking feed intake on an individual sow basis can also be very helpful, allowing managers and animal caregivers the ability to more accurately assess individual feeding levels and provide timely corrective action or intervention if sows are not consuming adequate levels of feed. Additionally, sow feed intake patterns can be evaluated assuming recordings are accurate and made on a consistent basis. There are many ways to estimate or measure individual feed intake. Ideally, if sows are fed from a feeding cart that contains a scale, actual weight of feed provided at each feeding for the sow can be determined and recorded on a lactation feeding card for each individual sow. However, a fairly close estimate of individual sow feeding levels can be made by determining the average weight of a scoop of feed, then recording the number of scoops or an estimate based on number of scoops provided to the sow at each feeding. Recording this data on a lactation feeding card, such as the example in Figure 2, can provide a helpful management tool that graphically illustrates the sow’s feed intake pattern, allowing the producer to detect when alterations in feed intake occurs and thus more rapidly take steps to intervene.
Amino acid recommendations for lactating sows are presented for four different situations/examples in Table 1. These recommendations have been generated using the National Swine Nutrition Guide Nutrient Estimation and Diet Formulation software that was developed simultaneously with the guide, and utilizes the NRC (1998) lactation model (25) to estimate nutrient requirements and includes a safety margin above those requirements. We believe this model and approach will provide nutrient recommendations that allow for economical diets that optimize reproductive and litter performance. However, differences in certain conditions (i.e. genetics, economics, nutrient availability, nutrient profile, and nutrient interactions) may require deviation from the recommendations presented.
Nutrient recommendations for the lactating sow are largely driven by energy/feed intake, sow weight, expected change in sow weight over the lactation period, litter size, and expected litter performance. Inputting actual on-farm data into the model provides nutrient recommendations that will ensure optimal performance without providing nutrient levels in excess of the sow’s needs. The four examples provided in Table 1 demonstrate differences in sow parity and body weight, and expected litter size and performance. A 21 day lactation length and initial piglet birth weight of 3 lbs are assumed under thermoneutral conditions. Two examples for Parity 1 sows are provided, with one sow having greater milking production and feed intake, but losing more body weight and condition compared to the other. A similar scenario for multiparous (parity 2+) sows is also provided. Differences in energy and nutrient recommendations between parity 1 and parity 2+ sows illustrates the value of providing separate parity-based diets for these two classes of sows if possible. Using the model, feed intake is increased when when body weight loss is reduced and/or litter growth performance in increased. Therefore, care must be taken to ensure that feed intake and litter performance levels are accurate, since most operations do not measure or know actual sow body weight loss in their herds.
Protein needs are expressed in terms of amino acid recommendations, reflecting that pigs require amino acids, not protein, in their diets to meet their needs. Lysine is the first limiting amino acid in grain-soybean meal-based diets. Amino acid recommendations are provided on a total basis and a standardized ileal digestible (SID) basis. Formulating diets on a SID basis allows one to account for differences in the useable amino acids present in the diet and more closely meets the pig’s amino acid needs while minimizing excess nitrogen excretion. Amino acid requirements are determined separately for maintenance and milk production (utilizing separate amino acid ratios relative to lysine for each; those are presented in PIG Factsheet #07-02-03 (Understanding Swine Nutrient Recommendations) and then are adjusted based on the amount of amino acids expected to be obtained from protein stores due to sow body weight loss. Finally, a 5% safety margin is provided over the actual estimated amino acid requirement levels to achieve our recommended levels.
In recent years, increased availability and reduced cost of many synthetic amino acids has increased their use, replacing part of the protein supplements typically included in swine diets. In sow lactation diets, when attempting to increase levels of synthetic lysine and utilizing our recommended amino acid ratios, synthetic lysine inclusion is limited by valine level (82 – 89% of lysine). Some nutritionists have utilized higher levels of synthetic lysine (5 – 6 lbs per ton of feed) by adding synthetic methionine and threonine are accepting a lower valine level (72% of lysine or less). It is our belief that the amino acid ratios provided by our recommendations, including that for valine, represent an accurate reflection of the whole body of literature and research that has been conducted. Slightly compromising any of the amino acid ratios can result in reductions in performance, but feed cost savings may offset this. Additionally, feeding any corn by-products (distillers grains, corn gluten feed, etc…) will allow increased inclusion of synthetic lysine in the diet since these ingredients are often higher in valine and some other amino acids relative to lysine than the protein supplements they are replacing.
For ease of use, amino acid levels as well as calcium and phosphorus recommendations are presented in terms of concentration in the diet (%) as well as level relative to energy (g/Mcal ME). Use of higher or lower energy diets compared to the recommendations provided in Table 1 may preclude the need to evaluate and formulate diets based on amount of nutrient/unit of energy rather than strictly on an overall diet concentration basis, as has been traditionally done. Use of this approach allows users to more accurately supply nutrient levels when utilizing alternative ingredients.
Calcium and phosphorus recommendations are provided in Table 1, and indicate levels we feel will be adequate to meet sow needs in most situations without excessive supplementation that can increase diet cost and excretion of these minerals. These levels were established based on a review of past and current university and industry research, and do not utilize the National Swine Nutrition Guide software model as previously described for amino acid recommendations. Including phytase in the diet for lactating sows can also help producers maintain performance while reducing manure phosphorus excretion and potentially cost. More information on phytase usage is provided in PIG Factsheet #07-03-04 (Feed Additives for Swine – Enzymes and Phytase).
Similarly, vitamin, trace mineral, and salt recommendations were determined and are presented in Tables 2 and 3. Due to the wide range in values that have been published and lack of current research defining precise requirements, ranges have been provided (Table 2). Except for salt, the minimum values generally represent the total amount required in the diet according to the NRC (1998). Upper values do not represent safe or tolerance levels, but instead a reference point above which further additions will not likely improve performance.
Higher producing (and multiparous) sows may require greater levels of these vitamins and trace minerals, and therefore it is suggested that producers utilize the higher values in the range for diet formulation purposes. Note that these values indicate levels of dietary addition and do not account for nutrient levels that may be present in other ingredients. Therefore, if producers are considering ingredients that may contain large levels of available nutrients, or especially salt, their contribution to the overall level of that nutrient in the diet should be considered.
Specific recommendations for trace mineral and vitamin additions to sow lactation feed are shown in Table 3. The values represent our best estimate of trace mineral and vitamin needs of lactation sows in practical situations. These values are based on NRC requirements to which a safety margin has been added. Those seeking nutritional information for manufacturing base mixes and premixes for swine diets can consult PIG Factsheet #07-02-06 (Trace Minerals and Vitamins for Swine Diets).
Table 1. Amino acid, calcium and phosphorus recommendations for lactating sows (as-fed basis)ab
|Sow parityc||Parity 1||Parity 1||Parity 2+||Parity 2+|
|Assumed sow lactation wt change, lb||-25||-10||-10||+5|
|Assumed sow daily feed intake, lb||11.8||10.1||14.2||12.3|
|Assumed daily piglet wt gain, lb||0.49||0.40||0.49||0.40|
|Assumed litter size weaned||11||10||12||11|
|Assumed litter wean wt, lb||145||115||160||125|
|Dietary metabolizable energy, Mcal/lb||1.50||1.50||1.50||1.50|
|% of diet|
|Standardized ileal digestible|
|Methionine + cysteine||0.46||0.41||0.44||0.39|
|Phenylalanine + tyrosine||0.96||0.84||0.93||0.82|
|Standardized ileal digestible|
|Methionine + cysteine||1.39||1.23||1.34||1.17|
|Phenylalanine + tyrosine||2.90||2.54||2.81||2.48|
aAll diets are full-fed under thermoneutral conditions. bSow performance assumptions: 21-day lactation length, initial piglet weight = 3 lb, sow weight at weaning = 350 – 400 lb (parity 1) and 400-450 lb (parity 2+). cParity 1 = first lactation period; parity 2 = second lactation period. dTotal phosphorus recommendations should be used as a guideline only; those recommendations may not be obtained when formulating practical diets on an available or digestible phosphorus basis which is recommended. Also, total phosphorus recommendations will not be achieved when phytase is included in the diet. eRecommended amount relative to dietary metabolizable energy (ME) density; energy values of ingredients from PIG Factsheet #07-07-09 (Composition and Usage Rate of Feed Ingredients for Swine Diets) were used in the calculations.
Table 2. Ranges for recommended dietary additions of salt, trace minerals and vitamins from concen- trates, base mixes or premixes for lactating swine (for specific dietary additions, see Table 3)a
|Salt, %||0.4 to 0.6|
|Sodium, %||0.15 to 0.25|
|Chloride, %||0.12 to 0.3|
|Copper, ppm||5 to 20|
|Iodine, ppm||0.15 to 0.5|
|Iron, ppm||80 to 200|
|Manganese, ppm||20 to 45|
|Selenium, ppmc||0.15 to 0.3|
|Zinc, ppm||50 to 200|
|Vitamin A, IU/lb||1800 to 7000|
|Vitamin D3, IU/lb||90 to 700|
|Vitamin E, IU/lb||20 to 40|
|Vitamin K, mg/lbd||0.25 to 3|
|Riboflavin, mg/lb||2 to 8|
|Niacin, mg/lb||5 to 35|
|Pantothenic acid, mg/lb||5 to 20|
|Choline, mg/lbe||250 to 500|
|Biotin, mg/lb||0.1 to 0.3|
|Vitamin B12, mg/lb||0.007 to 0.02|
|Folic acid, mg/lb||0.6 to 1.8|
|Vitamin B6, mg/lb||0 to 2.25|
aAll diets are full-fed under thermoneutral conditions. See Table 1 for feed intake and animal performance assumptions. bMinimum values generally represent the quantity recommended by the NRC (1998). Upper values do not represent safe or tolerance levels, but instead a reference point above which further additions will not likely improve performance. Older sows may require increased concentration of vitamins and trace minerals in their diets to optimize reproductive performance and enhance length of productive life. Producers seeking to implement parity-based feeding programs in lactation may consider using values toward the higher end of the ranges provided to supplement diets for older sows. cMaximum legal addition is 0.3 ppm. dMenadione activity. eNRC requirement (which represents total dietary concentration) is 450 mg/lb.
Table 3. Specific recommended dietary additions of trace minerals and vitamins from concentrates, base mixes, or premixes for lactating swine
|Vitamin A, IU/lb||4000|
|Vitamin D3, IU/lb||300|
|Vitamin E, IU/lb||30|
|Vitamin K, mg/lbd||2|
|Pantothenic acid, mg/lb||10|
|Vitamin B12, mg/lb||0.01|
|Folic acid, mg/lb||0.75|
|Vitamin B6, mg/lb||0|
aSalt is usually added at the rate of 10 lb/ton in sow diets to help provide a significant portion of the total dietary sodium and chloride recommendations. bRecommendations for sodium and chloride represent total dietary amounts, not additions. cMaximum legal addition is 0.3 ppm. dMenadione activity.
The overall goal of the feeding program for lactating sows should be to economically optimize energy and nutrient intake in order to support sow body maintenance and maximize litter performance while minimizing negative effects on subsequent return to breeding, litter size, and sow longevity. In order to accomplish this, energy (feed) intake levels must be maximized during the lactation period, and other nutrient levels provided at an appropriate recommended concentration in the diet based on actual sow feed intake levels. Many factors, including non-nutritive management practices, affect sow feed intake and ultimately sow performance, and thus must be accounted for. Only then, when these factors are addressed and are accompanied by an appropriate lactation feeding program, can sow and litter performance be optimized.
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Frequently Asked Questions
Can gestation and lactation diets be the same?
Use of the same diet for both gestation and lactation is discouraged. However, in smaller herds, it may not be practical to store and use two different diets for the sow herd. If this is the case, diets should be formulated to meet sow needs during lactation, since these are considerable greater than during gestation. Feeding 4 – 6 lbs of the lactation diet to sows during gestation will meet nutrient needs, but will also result in nutrient excesses (particularly amino acids) and more expensive feeding costs than when feeding separate gestation and lactation diets. Alternatively, a gestation diet can be provided to lactating sows along with including a topdress of soybean meal or other high protein/energy source in order to reduce overall feed cost, although ability to meet the lactating sows’s nutrient requirements may not be as accurate.
Should all sows receive the same lactation diet?
First parity sows, if possible, should receive different diets than multiparous sows. First parity sows consume less feed and are still growing, and therefore amino acid concentrations in the diet should be greater than for older sows. On average, first parity sows require at least 0.20% higher lysine concentration in the diet to maintain the same level of litter weaning weight as older multiparous sows. In most situations, all sows are housed in the same facility and are fed the same diet. In this situation, it is generally accepted that is it better to formulate diets closer to the requirements of the young sows and oversupply nutrients to the older sows, although overall diet cost/sow will increase some. Another option is to formulate the lactation diet to meet the older sow requirement, and provide a higher protein top dress for younger sows in order to meet their greater amino acid needs.
Will higher dietary levels of calcium, phosphorus, and other nutrients improve feet and leg soundness?
Probably not, although proper nutrition is clearly important in maintaining feed and leg soundness. Many research studies have investigated the influence of nutrition on feet and leg soundness. As long as diets contain nutrient densities similar to recommendations, provided in this guide, any feet and leg soundness problems encountered likely are caused by genetic or environmental factors other than nutrition.
Should feed flavors be used in lactation sow diets?
Many producers have considered using flavor enhancers in lactating sow diets to increase palatability and ultimately feed intake. Many experiments have been conducted with mixed results. Some trials indicate improvements in sow feed intake and reduced body weight loss when fed throughout lactation, some trials indicate that feed intake can only be increased when flavors are changed every couple of days, while other trials have demonstrated no appreciable effects. Very little is known about what specific flavors pigs prefer, and since these feed flavoring agents tend to be expensive and do not provide any nutritive value, caution should be used when considering their use.may be present in other ingredients. Therefore, if producers are considering ingredients that may contain large levels of available nutrients, or especially salt, their contribution to the overall level of that nutrient in the diet should be considered.