Grow - Finish Nutrition Concepts: Impact of Nutrition on Lean Growth

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1 Nutrition Vol. 2 No Technical Update Grow - Finish Nutrition Concepts: Impact of Nutrition on Lean Growth Introduction The pig industry must continue to improve the efficiency and quality of meat production in order to sustain a competitive position on the global market. Efficient production requires a genetic package that delivers: a high output of weaned pigs (24-28 pigs/sow/year), that can grow rapidly ( lbs/d) and efficiently under commercial conditions; they must have a high lean percentage and desirable meat quality and the production system must manage sub-clinical disease since health normally is the first limit to the expression of genetic potential for growth. The choice of genetics is important since it sets the 'ceiling' for growth performance and meat quality. However, inadequate management of the environment (health, temperature) and nutrition will lower the operational ceiling. Development of the optimum nutrition program requires an understanding of commercially achievable rates and efficiency of gain, percent carcass lean and carcass yield. Each are influenced by nutrition. The balance that must be achieved between nutrient input and performance output to optimize profit varies with the payment system. There are no short cuts to finding the proper balance. The best estimate for the Lysine:Energy ratio must be selected and then challenged through onfarm test. The purpose of PIC USA Nutrition guidelines is to provide a starting point for nutrient levels that support expected performance under good commercial conditions. Data are also provided to illustrate how the growth response varies with nutrient level. This Update discusses the impact of Nutrition on lean growth. Nutrient specifications for the grow-finish phase are presented in a companion Update (Vol. 2 No. 2). Nutritional Guidelines for all phases of production are presented in a single guide (Vol. 1 No. 1).

2 Table 1. Expected Performance Levels for Progeny of PIC 300 Series Sires Item Commercial Potential a Suggested Targets b Growth rate, lbs/day c 1.95 (.89kg) 1.82 (.83) Feed: Gain c Lean growth, lbs/day c 0.95 (.43kg) 0.89 (.40) Feed:Lean Gain FOM backfat, in (19mm) 0.80 (20.3) Lean % a From PIC USA Oklahoma multi-site system (5000 head/site) weight range, lbs (27-118kg), Mixed sex. b Based on data for 2 midwest producers (over 100,000 head). c Corn-soybean meal diets with 1% added fat. Performance Targets Growth rate (ADG) and feed conversion (FCR) have the greatest impact on profitability after market price. FCR is primarily driven by percent carcass lean (or body fat to lean ratio) and determines the diet Lysine:Energy ratio. Realistic performance levels are provided in Table 1 for progeny of PIC terminal sire products (327,337,356) mated to Camborough 22 sows. ADG and FCR data represent achievements when sub-clinical disease was properly managed and when reared under conditions of thermo-neutral temperature with adequate nutrition. Appendix Table 1 shows how environment and animal variables impact performance. The PIC Growth model allows for more dynamic estimates. Progeny of the three PIC 300 series sires have similar ADG and FCR. Nutrient specifications are the same since the composition of daily gain is virtually identical. Meat quality and carcass yield differ slightly among their progeny and forms the basis for market-based choices. PIC 427 sires are available for certain niche markets. Their progeny are inferior to PIC 300 series progeny in ADG, FCR and meat quality. However, PIC 427 progeny excel in carcass yield and lean content. The biological capacity for growth is determined by genotype, sex and body weight. However, the degree to which this can be expressed is dependent on external factors such as immune stress, thermal stress and nutrition. The biggest constraints to the expression of genetic potential for ADG are heat and disease. Each can be devastating to ADG and should be investigated prior to any consideration of a suspected nutritional limit to growth. FCR is the most sensitive measure to monitor when comparing Nutrient levels.

3 Figure 1 Lean Tissue Growth Curves For Genetically Improved and Unimproved Pigs 1.2 Lean Gain, lbs/day Improved Unimproved Body Weight, lbs. Principles of Growth Lean Growth Patterns. The rate of lean tissue growth increases during early growth and eventually reaches a plateau. The point at which this plateau is achieved depends on the genotype and sex. In early maturing or unimproved pigs, maximum lean deposition may be achieved at smaller bodyweights and (or) decline sooner than later maturing improved pigs (See Figure 1). Once maximum lean deposition is achieved, it inevitably declines while fat deposition holds constant or increases. The rate of decline in lean deposition depends on the genetic line (under thermo-neutral conditions). Maximum lean growth may also be greater for improved pigs than for unimproved pigs (Krick and co-workers, 1992) and also differs with sex. Boars have the highest potential for lean tissue growth with gilts being intermediate and castrates having the lowest potential (see Boyd and Beerman, 1992). The ratio of body protein:fat is greater for improved pigs (as compared to unimproved pig), which accounts for the improved FCR and higher dietary Lysine:Energy need. Improved pigs require a more expensive diet but the cost of gain is lower than unimproved pigs because it contains more water. Immune Stress and Growth. Research with segregated early weaning shows that sub-clinical disease can de-rail genetic advances in ADG. PIC pioneered methods to manage sub-clinical disease by segregating young pigs from sows and then systematized site segregated rearing as a first step toward managing serial disease challenge for nursery and finish phases. This procedure allows producers to minimize exposure to chronic and acute disease so that they capture more of the genetic potential for growth. Therefore, achieving lbs/day ADG ( g/d) is commercially possible but it requires managing rather than treating disease (Table 1). The adverse effect of immune system stress on ADG and FCR was illustrated by PIC USA research (see Figure 2). High lean growth pigs were injected weekly with increasing levels of E. Coli endotoxin called lipopolysaccharide, LPS (PIC USA Exp. 9817). The challenge adversely affected both ADG and FCR. The mechanism by which a sub-clinical disease challenge disrupts growth is unclear. The effect may be to depress appetite directly. It may also involve depression

4 in the level of a key growth factor (IGF-1) for muscle growth. We have achieved closeout ADG in sites of 5000 pigs of lbs/day ( g/d) when sub-clinical disease was controlled through multi-site production. Failure to achieve the high rates of ADG generally means that immune stress exists to some degree, provided that thermal stress is not present. Compensating for depressed appetite through increased Nutrient input (Energy or Amino acid density) is not an effective means of overcoming the effects of immune stress because appetite is simply a reflection of the willingness of tissues to grow. Nutrition and Lean Growth. Inadequate dietary Nutrient concentration will compromise ADG, FCR and percent carcass Lean. The impact of Nutrient input on lean growth is illustrated in detail below. Diet and Lean Growth Pigs require a proper supply of nutrients to meet the demands for maintenance and tissue growth. The key nutrients for lean growth are energy, amino acids, phosphorus and B-vitamins. Energy is first limiting to growth. Dietary Energy. Feed energy is used for maintenance and then for protein and obligatory fat deposition. Energy supplied above the need for protein deposition will be deposited as fat and result in an increase in ADG and depression in FCR (see Figure 3, top frame, point B). In early growth (to about 160 lbs or 75 kg in PIC pigs), the potential for protein deposition is high and fat deposition is low (point A). Energy intake is low because tissue needs are low. The result is an impressive FCR. The dogma is that pigs cannot consume enough energy to maximize protein deposition during this phase. We believe that this interpretation is erroneous and that pigs weighing more than 40 lbs consume the amount of energy that is needed to support the tissue drive for protein deposition. They are unwilling to deposit fat at the high levels characteristic of later growth. Therefore, feeder management must allow for unrestricted feed access in order to support the increasing rates of protein deposition that are characteristic of the early growth phase. ADG during early growth can be rapid, very efficient and at relatively low cost ($/lb gain) when compared to later growth. Inadvertent feed restriction impairs growth without benefit to FCR during this phase. During later growth (beyond 195 lb or 90 kg), the PIC pig consumes more than enough energy to maximize protein deposition. Surplus energy is deposited as fat (see point B). This increase in fat tissue growth rate occurs because fat cells are becoming more responsive to the hormone insulin. Limiting energy during this phase by feeder restriction or with low energy density diets may not compromise protein deposition rate but back fat depth will be slightly reduced. There will also be a reduction in ADG, which must be considered in the cost-benefit analysis. FCR will be impaired with a reduction in dietary energy density. The source of dietary energy (fat vs carbohydrate) also influences the efficiency of gain. Pigs fed diets with added fat convert feed to body weight gain more efficiently (FCR). Fat addition appears to benefit ADG in nursery pigs to 40 lbs (18 kg) because of a physical limit to feed consumption. Fat addition to diets of pigs beyond 40 lbs results in a slight improvement in growth rate and FCR but the kcal ME/lb gain is similar (Tech. Report 48, 1997). It is not clear whether the percent improvement in ADG and FCR with fat addition differs for early (50-150

5 lbs) as compared to later growth ( lbs) for PIC 300 series progeny. These relationships are being determined under commercial conditions to aid in Energy optimization considerations. An increase in dietary energy density beyond that typical of the Corn-Soy diet (e.g., from 1500 kcal NRC ME to 1570 Kcal) during the grow-finish period may lead to a slight increase in fat depth ( mm). This difference may be even greater if (1) the Lysine:ME ratio is not maintained at required levels, or (2) if high levels of dietary fat are added (> 5-6%). The dietary energy density ( Kcal ME/lb) that optimizes profit depends on a number of factors since ADG, FCR, lean %, carcass yield and $/lb of gain are all affected. These concepts are discussed in a recent review by Usry and co-workers (1998). Figure 2 Immunte Stress Modifies Growth and Feed Efficiency in Growing Pigs Control LPS Control LPS ADG, lbs/d F/g ratio *LPS, Lipoplysaccharide - see

6 Figure 3 Relationship Between Energy Intake and Deposition of Body Protein and Fat Gain of Fat and Muscle, g/day Fat Muscle A B Diet Energy Intake, Mcal/day Low Feed Intake. PIC pigs are expected to have a lower feed intake (FI) than competitor products because they deposit less fat and more water. Put another way, fat pigs require more feed. The analysis should focus on whether ADG meets or exceeds target. The lower FI is simply a reflection of improved FCR. If ADG is below expectations, the analysis should then focus on what is limiting growth, which, inturn; determines the amount of FI needed. Amino Acid Supply. Amino acid intake also influences ADG, composition of growth and therefore FCR. An amino acid deficient diet reduces muscle growth rate and increased body fat deposition results. Energy that is normally used to synthesize muscle is diverted to body fat. The relationship between amino acid intake and performance is shown in Figure 4. Increasing dietary lysine percentage from deficient to adequate levels also increased protein deposition and decreased body fat with the result being improved ADG and FCR (data not shown).

7 Figure 4. Relationship Between Amino Acid Intake and Performance of Growing Pigs Efficiency of Gain (F/G) Efficiency of Gain (F/G) Krick et al Dietary Lysine Intake, g/day The effect of an amino acid deficiency on the response of experimental pigs (see Figure 4) tends to be a little more pronounced than is typically observed under good commercial conditions because the latter are more variable in weight and age. In other words, the response curve to dietary Lysine has a lower slope for a commercial test compared to more controlled experiments. In trials conducted under commercial conditions, a 15% deficit in dietary lysine percentage from lbs. reduced ADG by about 0.05 lbs/day, FCR by 0.07 units and increased backfat depth by 1 mm (Tech. Memos 160 and 183, 1997). In contrast, feeding diets that contained a 10-12% excess of amino acids depressed ADG by 0.06 lbs/d, FCR by 0.06 units but no effect was observed for fat and loin depth (Tech. Memos 183 and 204, ). The adverse effect of excess amino acids on FCR is more pronounced with temperature stress (Tech. Memo 183, Exp. No. 9611) since heat increment needs to be reduced rather than increased. This reduction in tissue growth with oversupply of amino acids is due to the fact that excess amino acids must be degraded and removed from the body. This is an energy requiring process. The effect of amino acid oversupply under conditions of thermal neutrality and thermal stress is shown in Figure 5. Note that FCR improved with each increment of Lysine until the optimum FCR was achieved (i.e., maximum body protein:fat ratio). FCR began to erode after the optimum Lysine percentage was achieved but was more pronounced under temperature stress.

8 Figure 5 Response to increasing dietary Lysine under two Enviornmental temperatures 4.4 PIC USA Exp Feed Conversion, F/G Heat Thermoneutral Dietary Lysine, % Amino Acid Balance. Dietary protein is required to supply the essential amino acids and sufficient amino acid nitrogen for the pig to manufacture the so-called 'non-essential' amino acids. Essential amino acids must be provided pre-formed in the diet. Protein deposition will be decreased and ADG, FCR and lean percent will each be compromised if one or more of them are deficient. Table 2. Ideal Balance of the most Limiting Amino Acids Amino Acid % of Lysine a Dietary % b Lysine Threonine Methionine Met + Cystine Tryptophan Isoleucine a Pattern from PIC Nutrition Update for 5-50 lb ( kg). b Assumed female during lb (23-44 kg) growth phase. The balance of amino acids is said to be ideal when each essential amino acid and non-essential amino acid nitrogen exactly meet the need for growth, lactation etc. This would not occur under practical situations, however, the concept of an ideal balance for the most critical amino acids is important to diet formulation. The minimum balance for the most limiting amino acids for G-F pigs is shown in Table 2. Each amino acid is required in a specific ratio to lysine in order for protein synthesis to occur. The practical benefit of having ideal amino acid patterns is that if the

9 lysine requirement is known for the phase of growth, then minimum levels for other critical amino acids can be specified. Amino acids supplied by dietary protein in excess of the ratio shown will be degraded and the residual nitrogen excreted in urine. Formulating diets to Lysine levels (% or g Lysine:Mcal ME) that exceed the minimum requirement for optimum FCR and lean percent is expensive. The cost of over-fortification of Lysine is even greater when one formulates to achieve a minimum level for the most limiting 3-4 amino acids since all of them would be over supplied. On-farm verification that Lysine levels are at profit optimum will result in a percentage that is < 100% of the need for every pig. Formulating to the minimum level of other amino acids using the ideal pattern will then be less apt to be excessive and costly IF the ideal pattern is reliable. The pattern varies with phase of growth and physiological state (growth vs lactation) and is presented in Vol 1 No. 1. A deficiency of one or more amino acids in relation to lysine will depress performance even though the intake of lysine and other amino acids is adequate. This concept is illustrated in Figure 6. Less of a properly balanced protein is required to achieve the maximum response. Formulating to the most limiting 4-5 amino acids generally assures that the need for all 10 amino acids will be exceeded. A protein that is deficient in one or more amino acids will compromise ADG unless a greater amount is consumed. Table 3. Amino Acid Balance When Formulating Using the Thumbrule a 1.15% Lysine b 0.80% Lysine c Amino Acid Ideal Pattern Corn-Soy Milo Soy Ideal Pattern Corn-Soy Lysine 100% 105% 104% 100% 100% Methionine Methionine d Cystine Threonine Tryptophan a Thumbrule is 3 lbs synthetic Lysine per ton for corn-soybean diets. All diets were formulated using 3 lbs Lysine per ton. b Ideal pattern relative to Lysine for early (to 110 lbs) and late (>175 lbs) growth respectively. c Percent of the dietary amino acid relative to Lysine. d Box denotes a deficit.

10 Figure 6. Performance Depends on Proper Amino Acid Balance Balanced Lean Tissue Growth Rate Unbalanced Protein Intake, g/day Table 4. Change in the Lysine to ME Ratio in PIC females with Stage of Growth Body weight, lbs. Lysine:NRC:ME, a,b g /Mcal ME a Total Lysine specified assuming a corn-soy diet. Digestible lysine assumed to be 83% of total. b Values derived from Nutrition Update Amino Acid Digestibility. The ability of dietary ingredients to meet minimum levels of each amino acid differs with stage of growth and with the digestibility of amino acids contained by the ingredient. This concept is discussed in greater detail in a Biokyowa report (Tech. Rev., 1991). PIC guidelines for Lysine and other amino acids are presented on a total basis assuming that a corn-soy diet is used. True Digestible Lysine needs are also presented for those using more complex formulas. We prefer the use of True as compared to Apparently digestible estimates. The ideal balance that one uses is the same when using Total and True digestible amino acid levels but the balance is slightly different when Apparently digestible estimate are used (See Vol. 1 No. 1). The amount of synthetic Lysine that is needed varies with stage of growth and complexity of diet formulas (vs Corn-Soy). The historical 'thumb-rule' of 3 lbs of synthetic Lysine is applicable to Corn-Soy diets under most situations. It doesn t hold true for the more complex diets. During early growth (1.15% Lysine), 3 lbs. of synthesized Lysine is too much unless methionine is also used (Table 3). Addition of 3 lbs. Lysine to a milo-soy diet results in a deficit of total sulfur amino acids (Met + Cystine). The Historical rule applies well to mid and later growth if fed Corn-soy diets (See Table, 0.80%). More complex formulas involving alternative ingredients

11 (e.g., wheat midds, canola and 2-3 synthetics may require 4-5 lbs. synthetic Lysine per ton of diet, to achieve the proper balance of digestable amino acids. Average Daily Gain lbs. Figure 7. Effect of B-Vitamin Levels on ADG and FCR of High Lean Pigs Stahly et al., kg pigs Feed/Gain ratio Dietary B-Vitamins, % of NRC Feeding lower protein, amino acid supplemented diets, is a means of reducing excess amino acids and nitrogen pollution. This can be of practical significance for young nursery pigs where protein load needs to be reduced and net energy increased. It may also be one of several strategies used in hot environments to decrease metabolic heat production to minimize its negative effects on FCR and ADG. For these reasons, the addition of 1-3 synthetic amino acids has become routine. This procedure is also a means of keeping soybean meal use in formula's to the maximum level without exceeding dietary protein maximums. Integrating Energy and Amino Acids. Energy and amino acid nutrition cannot be considered in isolation to one another. The supply of amino acids must be in proper balance to one another and then in balance to dietary energy concentration. In general, a higher lean gain potential requires a higher Lysine:Energy ratio. A higher Lysine:Energy ratio is required in the early stages of growth when the body protein (or lean):fat ratio is high. The Lysine:Energy ratio can be reduced as the pig grows because of a declining protein to fat ratio in the daily gain. This is shown in Table 4. If the Lysine:Energy ratio is deficient for the stage of growth, then the rate of protein deposition will be reduced and body protein:fat ratio will be below genetic potential.

12 Surplus energy will be available for added fat deposition, which will occur at all stages of growth. FCR will be hurt. When dietary energy concentration is increased beyond typical corn-soy levels through fat addition, the Lysine % needs to be increased in order to maintain the specified Lysine:ME need. Specifications in Table 4 can be used to set dietary Lysine levels when diet ME levels vary. For example, a lb pig (23-41 kg) requires 1.05% total lysine when a 1500 Kcal/lb diet (3300 Kcal/kg) is fed. However, if the addition of fat results in a diet with 1580 KcalME/lb (3475 Kcal/kg), then 1.10% lysine is needed in order to maintain the specified 3.18 Lysine:ME ratio. Phosphorus. The requirement for available phosphorus and B-Vitamins also depends on the capacity for protein deposition and the FCR achieved. Feeding deficient levels of dietary phosphorus depressed ADG and FCR (ISU Research Report, 1995a). A progressive increase in phosphorus need was required with increased lean growth capacity. PIC recommendations for available phosphorus attempt to balance dietary needs for lean content against cost and environmental concerns. Additional considerations for recommended phosphorus levels include: (1) correction for the genetic advances in FCR over the past 6 years with an allowance for the (2) extraordinary force of muscle contraction that is produced with commercial "stunning" at slaughter. This requires a stronger bone than normally needed for the better-controlled conditions of University Meat Labs. We discourage elimination of either Ca-P supplements during part or all of the final phase of growth. Our recommendations show a marked reduction in Total or Available Phosphorus during the final 50 lbs (23 kg) of growth. B-Vitamins. The importance of adequate B-vitamin supplementation was also emphasized in Iowa State research (ISU Research Report, 1995b). Growth rate and FCR were improved with each increment of B-vitamins addition to 5 times NRC-1988 for nursery pigs having high lean growth capacity (see Figure 7). Three times the NRC concentration was needed for moderate lean-growth rate pigs (data not shown). This result has been shown for pigs up to at least 60 lbs body weight. Vitamin need may also be greater with increased stress (Coelho and Cousins, 1997) but practical recommendations are not possible given present research.

13 Profit Optimization Lysine Levels Establishing the optimum nutritional program requires 'standing' the economic cost of dietary inputs against performance output and lean payment. Making decisions based on cost per ton of diet alone is misleading. The correct procedure is to (1) determine the Lysine level that optimizes profit and then, (2) to work toward reduced diet cost per ton within those specifications. Use of alternative ingredients, where possible, and making certain that the proper amount of diet is fed within each phase (feed budget) are important but often missed considerations. ( + ) FIGURE 8. Performance Response and Dietary Nutrient Concentration Maximum Profit Maximum Response Performance Level Dietary Lysine Percent ( - ) Genetically lean pigs consume less feed but require a higher concentration of nutrients in order to maintain constant nutrient intake per unit of lean tissue. The good news is that this allows each pound of gain to contain more water. Therefore, the diet cost ($/ton) is greater for high lean growth pigs, but the nutritional cost per unit of gain is less under most circumstances. The same is true for Nursery pigs. Nursery diets are significantly more expensive, but the improved FCR generally leads to a lower cost of gain when compared to pigs during the Finish phase.

14 Table 5. Profit Optimization under Commercial Conditions: Economic Comparison, using performance responses to 4 Lysine Curves (gender combined) Lysine % Diet Cost a $/ton ADG lbs/d FCR lbs/d Feed Cost b $/200 lbs Housing c $/pig Total $/pig $ (+4d) (+3d) (+0d) (+1d) Total Feed and Housing Cost Adjusted for Carcass Discounts. Carcass Value, $/cwt d FOM BF Mm FOM Lean % FOM Mus mm Plant A Plant B Adjusted c Cost, $/pig a Weighted diet cost across 4 phases of growth. b Assumes 200 lbs of gain. c Assumes 12 /pig/day. d Actual Plants, December 1997 payment. Plant A premium for % lysine curve is $3.50 cwt carcass. Plant B premium is $2.76 cwt. Carcass yield assumed constant at 75% e Adjusted cost is total production cost ($/pig) corrected for Swift carcass value as follows: (Feed cost and Housing cost) - carcass value. The optimum nutritional program is often, but not always, one that economically supplies the nutrients needed to express the pig's capacity for lean tissue growth. The difficulty is choosing the proper level for a population of pigs that vary widely in lean composition. A typical response curve is shown in Figure 8 for dietary Lysine:ME (conceptual model). Formulating to achieve the maximum group response means overfeeding most of the pigs to provide the higher levels needed by a few. This is generally not cost effective. Meeting the needs for 85-92% is generally closer to maximum profit when diet cost is compared to performance (ADG, FCR, lean %). The data in Table 5 illustrates an important point relative to optimizing profit. The most costeffective curve for a lean payment program was the 1.10% Lysine curve (4 phases beginning with 1.10% and ending with 0.85% lysine). Better ADG and FCR partially covered increased diet cost but carcass benefits were needed to result in greatest profit (shown as reduced "net feed cost"). Feeding to the highest lysine level (1.25% Lysine curve) resulted in greater feed cost without further benefit to ADG, FCR or carcass lean. On the other hand, the best program for a live weight basis (0.95% Lysine curve) was about 13-15% below the curve that optimized lean. Even though some decline in ADG and FCR resulted, total feed plus housing cost was lower than the 1.10% Lysine curve. Therefore, the correct curve depends on farm specific costs in relation to performance trade-offs and the packer lean payment program. Data from Table 5 could be used to develop a simple spreadsheet to estimate profit optimization under different market conditions. PIC Nutrient Specifications PIC nutrient specifications are suggested levels based on our experience for optimum profit performance. They are presented in brief form in PIC USA Nutrient Specifications (Vol. 1. No. 1) and are presented in greater detail in the companion to this Update in this Grow-Finish series.

15 (Vol. 2 No. 2). On-farm verification will continue to be a must in validating the optimum program for the packer payment matrix. This will require the ability to feed 2 different diet programs to challenge the current one. A simple method would be to use the same diets but to change the weights over which they are fed to a challenge group (by lbs). Pigs must be in the same barn and under identical management. SUMMARY Key Nutritional Concepts for Lean Optimization 1. Maximum lean gain is dependent upon proper Nutrition. 2. Key Nutrients for lean growth: Energy Phosphorus Amino acids B Vitamins 3. Limiting Energy intake during early growth compromises rapid lean growth. 4. Limiting Energy intake during late growth may improve lean percent but growth rate (ADG) and feed efficiency (FCR) will deteriorate. 5. Insufficient Amino Acid intake will compromise ADG, FCR and Lean. 6. Amino acid balance is critical. Deficiency of a single Essential Amino Acid limits lean deposition to the level of that Amino Acid. 7. Dietary Lysine and Energy must also be in proper balance. The Lysine:ME ratio declines as the pig grows. % Lysine must increase with fat addition to maintain Lysine:ME ratio. 8. Phosphorus and B-Vitamin needs increase with Lean growth capacity. 9. Vitamin needs may be greater during stress. 10. Water is the Central Nutrient. Flow rate, availability and quality are critical. Bottom-line: High lean PIC pigs require more expensive diets ($/ton), but the improved FCR reduces cost of gain ($/lb gain). Lean payment further improves profit potential.

16 Appendix Table 1. Impact of Animal and Environmental Variables on Growth and Carcass Lean Variable Daily Feed: Gain a Backfat b Lean Gain Market Weight: (lbs/d) (F/G) (mm) % Increase from 240 to Below.06 Below.04 Below 0.5 Below lbs (cumulative change per 10 lbs) Avg. from Above.02 Below.16 Below 2.0 Above 0.8 vs lbs Gender Below.11 Below.07 Below 3.0 Above 2.4 Gilt vs. Castrate Sire Line NC NC Above.75 Below 0.5 PIC 337 vs. PIC 327 Diet Lysine: ME Below.05 Above.07 Below 1.0 Below % below max lean 15% above max lean Below.07 Above.07 NC NC Thermal Stress c 15 F above UCT 16 hr Below.35 Above.05 Above 1.4 Above 0.7 a Mortality adversely affects F/G by for each 1% change. Floor space adversely affects gain by -.06 and F/G by +.05 per square ft 2 decrease in the 8.8 to 5.3 ft 2 range during GF phase. b Location difference: P 2 vs 10th rib (P mm), 10 th vs. last rib (10 th, -1.4 mm). c PIC USA Exp ( lb phase of growth). References Biokyowa Technical Review No Digestible amino acids and digestible ammo acid requirements for swine, Bertram, M.J., T.S. Stahly, and R.C. Ewan. 1995a. The impact of dietary phosphorus regimen on muscle quality in pigs of high and moderate lean growth genotypes. ISU Swine Research Report, ASL-R1262. Stahly, T.S., N. Williams, S.G. Swenson, and R.C. Ewan. 1995b. Dietary B vitamin needs of high and moderate lean growth pigs fed from 20 to 62 pounds body weight. ISU Swine Research Report, ASL-R1263. Krick, B.J., R.D. Boyd, and co-workers. Influence of genotype and sex on the response of growing pigs to recombinant porcine sonatotropin J.Anim. sci.70:3024. Krick, B.J., R.D. Boyd, and co-workers, Somatotropin affects the dietary lysine requirement and net lysine utilization for growing pigs. J. Nutr. 123:1913.

17 J. Usry, R. G. Campbell and D. Burnham. Optimizing energy formulation for finishing swine Proc. Carolina Swine Nutrition Conf., Raleigh, NC. Boyd, R.D. and D.H. Beerman Manipulation of Body Compostition. In Diseases of Swine, 7th ed. Iowa State Univ. PIC USA Tech. Memo Comparison of two dietary lysine standards for growing PIC pigs: PIC USA vs U. Illinois. PIC USA Tech. Memo Dietary lysine curve that optimizes lean growth and profit for PIC427 progeny. PIC USA Exp Lysine dose response curves for lb PIC pigs reared in a hot vs thermo-neutral environment. PIC USA Nutrition Tech. Update. Vol. 1 No PIC USA Tech. Report Comparison of two energy strategies for growth. PIC USA Exp , Immune System challenge of growing pigs. Coelho, M.B. and B. Cousins Vitamin supplementation supports higher performance. Feedstuffs, Jan ,

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