Effects of varying creep feeding duration on proportion of pigs consuming creep feed and preweaning

Similar documents
Effects of Creep Feed Pellet Diameter on Suckling and Nursery Pig Performance

Effects of different feed mills and conditioning temperature of pelleted diets on nursery pig performance and feed preference from 14 to 50 lb

DETERMINING THE THREONINE REQUIREMENT OF THE LACTATING SOW 1

EFFECTS OF A LIQUID (NEOLAC 1 ) AND DRY FEED COMBINATION FED IN VARYING DURATIONS ON WEANLING PIG PERFORMANCE

Effects of XFE Liquid Energy and Choice White Grease on Nursery Pig Performance 1

Kansas Agricultural Experiment Station Research Reports

Effect of glycerol on pellet mill production efficiency

THE EFFECTS OF POULTRY MEAL AND FISHMEAL ON GROWTH PERFORMANCE OF WEANLING PIGS 1

Effects of dietary Vitamin E level and source on sow, milk, and piglet concentrations of α- tocopherol

Effects of Dietary Standardized Ileal Digestible Isoleucine:Lysine Ratio on Nursery Pig Performance

A COMPARISON OF WHEY PROTEIN CONCENTRATE AND SPRAY-DRIED ANIMAL PLASMA IN DIETS FOR WEANLING PIGS 1

Effects of AV-E Digest and XFE Liquid Energy on Nursery Pig Performance 1

EFFECT OF WHEY PROTEIN CONCENTRATE SOURCE ON GROWTH PERFORMANCE OF NURSERY PIGS

Evaluation of Antibiotics and Benzoic Acid on Growth Performance of Nursery Pigs 1

Comparative effects of dietary copper, zinc, essential oils, and chlortetracycline on nursery pig growth performance

EFFECTS OF PELLETING AND PELLET CONDITIONING TEMPERATURES ON WEANLING PIG PERFORMANCE 1

THE EFFECT OF A PROBIOTIC, KE-01, AND NEOTERRAMYCIN ON NURSERY PIG GROWTH PERFORMANCE 1

Effects of Increasing PEP-NS on Nursery Pig Performance 1

Evaluation of Fermented Soybean Meal Sources in Diets for Nursery Pigs 1

Effects of Increasing Wheat Middlings and Net Energy Formulation on Nursery Pig Growth Performance

THE EFFECTS OF DIETARY GLUTAMINE, GLYCINE, AND SODIUM CHLORIDE CONCENTRATION ON NURSERY PIG GROWTH PERFORMANCE

ADG (P<0.03) and ADFI (P<0.05). Increasing Neomycin sulfate in the feed improved. Summary

DETERMINING THE EFFECT OF RESTRICTED FEED INTAKE ON DEVELOPING PIGS WEIGHING BETWEEN 150 AND 250 LB, FED TWO OR SIX TIMES DAILY

THE ph OF SPRAY-DRIED BLOOD MEAL DOES NOT INFLUENCE NURSERY PIG PERFORMANCE 1,2

Effects of Different Feed Mills and Conditioning Temperature of Pelleted Diets on Nursery Pig Performance and Feed Preference from 14 to 50 lb

EFFECTS OF COPPER SULFATE, TRI-BASIC COPPER CHLORIDE, AND ZINC OXIDE ON WEANLING PIG GROWTH AND PLASMA MINERAL CONCENTRATIONS 1

An Evaluation of Peptone Products and Fish Meal on Nursery Pig Performance 1

Effects of Increasing Space Allowance by Removing a Pig or Gate Adjustment on Finishing Pig Growth Performance

EFFECTS OF PEPSOYGEN AND DRIED PORCINE SOLUBLES 50 IN NURSERY PIG DIETS 1

EVALUATION OF DIFFERENT SOY PROTEIN CONCENTRATE SOURCES ON GROWTH PERFORMANCE OF WEANLING PIGS 1

EFFECTS OF INCREASING DRIED DISTILLER S GRAINS ON FEED INTAKE

AN EVALUATION OF ASTAXANTHIN AS A NUTRACEUTICAL GROWTH PROMOTER IN STARTER DIETS FOR WEANLING PIGS 1

EFFECTS OF SOYBEAN MEAL SOURCE AND LEVEL ON GROWTH PERFORMANCE OF WEANLING PIGS

COMPARISON OF INTERNATIONAL PROTEIN CORPORATION 740 FISH MEAL AND SPECIAL SELECT MENHADEN FISH MEAL IN NURSERY PIG DIETS

Evaluation of Elarom SES with or without Tri-basic Copper Chloride on Nursery Pig Growth Performance

Evaluating the Efficacy of a Novel Phytase Source

COMPARISON OF WATER-BASED AND IN-FEED ANTIMICROBIALS FOR GROWTH PERFORMANCE ENHANCEMENT OF WEANLING PIGS

Effects of Increasing Crystalline Amino Acids in Sorghum- or Corn-based Diets on Finishing Pig Growth Performance and Carcass Composition

Effects of Monosodium Glutamate on 11- to 50-lb Nursery Pigs

Effects of Standardized Ileal Digestible Lysine Content in Low Crude Protein Diets on Finishing Pig Performance and Economics from 230 to 280 lb

J. M. Benz, M. D. Tokach, S. S. Dritz 2, J. L. Nelssen, J. M. DeRouchey, and R. D. Goodband

Effects of the Age of Newborn Pigs Receiving an Iron Injection on Suckling and Subsequent Nursery Performance and Blood Criteria

improved growth, whereas those provided organic acids in feed and water did not. Summary

Diet Formulation Method Influences the Response to Increasing Net Energy for Growing-Finishing Pigs

THE OPTIMAL TRUE-ILEAL-DIGESTIBLE LYSINE AND TOTAL SULFUR AMINO ACID REQUIREMENT FOR NURSERY PIGS BETWEEN 20 AND 50 LB 1

Effects of Dietary Vitamin E Level and Source on Sow, Milk, and Piglet Concentrations of α-tocopherol 1

EFFECTS OF RACTOPAMINE HCL (PAYLEAN) AND α-lipoic ACID ON THE GROWTH PERFORMANCE AND CARCASS CHARACTERISTICS OF FINISHING PIGS

Evaluating Pellet and Meal Feeding Regimens on Finishing Pig Performance, Stomach Morphology, Carcass Characteristics, and Economics

Comparative Effects of Dietary Copper, Zinc, Essential Oils, and Chlortetracycline on Nursery Pig Growth Performance 1

COMPARISONS OF LYSINE BIOAVAILABILITY IN SPRAY-DRIED BLOOD MEAL, BLOOD CELLS, AND CRYSTALLINE LYSINE IN NURSERY PIGS

EFFECTS OF EXTRUDED-EXPELLED SOYBEAN MEAL AND SOLVENT EXTRACTED SOYBEAN MEAL LEVEL OF GROWTH PERFORMANCE OF WEANLING PIGS 1,2

Kansas Agricultural Experiment Station Research Reports

INFLUENCE OF NUTRIDENSE LOW PHYTATE 1 CORN AND ADDED FAT ON GROWING-FINISHING PIG GROWTH PERFORMANCE

Evaluation of Heparin Production By-Products in Nursery Pig Diets 1

EFFECTS OF INCREASING AMOUNTS OF TRUE ILEAL DIGESTIBLE LYSINE ON THE GROWTH PERFORMANCE OF GROWING-FINISHING PIGS REARED IN A COMMERCIAL FACILITY 1

SUPPLEMENTATION OF L-CARNITINE AND PAYLEAN IMPROVE GROWTH PERFORMANCE OF PIGS IN A COMMERCIAL FINISHING FACILITY

The Effects of Wheat and Crystalline Amino Acids on Nursery and Finishing Pig Growth Performance and Carcass Characteristics 1

Effects of Monosodium Glutamate and AminoGut on Nursery Pig Performance

THE INFLUENCE OF DIETARY FAT LEVEL AND CRYSTALLINE AMINO ACID ADDITIONS ON GROWTH PERFORMANCE OF 25- TO 50-LB PIGS 1

SWINE DAY D. L. Goehring, M. D. Tokach, J. L. Nelssen, J. M. DeRouchey, R. D. Goodband, S. S. Dritz 3, and J. L. Usry 4

Variation in chemical composition of soybean hulls

Effects of Dietary Calcium and Phosphorus Concentrations and Addition of Phytase on Growth Performance of Nursery Pigs

EFFECTS OF INCREASING STANDARDIZED ILEAL DIGESTIBLE LYSINE:CALORIE RATIO FOR 120- TO 180-lb GILTS GROWN IN A COMMERCIAL FINISHING ENVIRONMENT 1,2

Effects of Crude Protein and Amino Acid to Lysine Ratio on Finishing Pig Growth Performance and Carcass Characteristics

EFFECT OF ADDED FAT ON PERFORMANCE OF GROWING-FINISHING PIGS IN COMMERCIAL CONDITIONS

EVALUATION OF THE OPTIMAL TRUE-ILEAL-DIGESTIBLE LYSINE AND THREONINE REQUIREMENT FOR NURSERY PIGS

Effect of Diet Complexity and Specialty Protein Source on Nursery Pig Performance

EFFECTS OF CORN SOURCE AND FAT LEVEL ON GROWTH PERFORMANCE OF GROW-FINISH PIGS REARED IN A COMMERCIAL FACILITY 1

Evaluation of Medium Chain Fatty Acids as a Dietary Additive in Nursery Pig Diets

Comparison of Different Antimicrobial Sequences on Nursery Pig Performance and Economic Return

Kansas Agricultural Experiment Station Research Reports

Amino acid digestibility and energy concentration of fermented soybean meal and camelina meal for swine

T.B. Morillo, S.D. Carter, J.S. Park, and J.D. Schneider. Story in Brief. Introduction

Effects of Increasing Crystalline Amino Acids in Sorghum-or Corn-based Diets on Nursery Pig Growth Performance

R. O. Gottlob, J. M. DeRouchey, M. D. Tokach, R. D. Goodband, J. L. Nelssen, S. S. Dritz 2, C. W. Hastad, K. R. Lawrence, and D. A.

Effect of Zinc Oxide, Zinc Hydroxychloride, and Tri-basic Copper Chloride on Nursery Pig Performance

Evaluation of Dietary Electrolyte Balance on Nursery Pig Performance

Effects of Increasing Copper from Tri-basic Copper Chloride or a Copper-Chelate on Growth Performance of Nursery Pigs

EFFECTS OF INCREASING CA:P RATIO IN DIETS CONTAINING PHYTASE ON FINISHING PIG GROWTH PERFORMANCE

EFFECTS OF INCREASING CRYSTALLINE AMINO ACIDS AND THE SUBSEQUENT CHANGE IN DIET NET ENERGY ON GROWING PIG PERFORMANCE 1

Effects of Feeding Varied Levels of Balanced Protein on Growth Performance and Carcass Composition of Growing and Finishing Pigs 1,2

POTENTIAL FOR EGG PROTEIN AND PORCINE SPRAY-DRIED BLOOD AS A REPLACEMENT FOR PLASMA PROTEIN (AP-920) IN EARLY- WEANING PIG DIETS

Effects of Xylanase in High-Co-Product Diets on Nutrient Digestibility in Finishing Pigs 1

Effects of Fe Dosage in Newborn Pigs on Preweaning and Subsequent Nursery Performance

USE OF INFRARED THERMOGRAPHY TO EVALUATE DIFFERENCES IN MEAN BODY SURFACE TEMPERATURE AND RADIANT HEAT LOSS IN GROWING PIGS

Starter Pig Recommendations

THE OPTIMAL TRUE-ILEAL-DIGESTIBLE LYSINE AND TOTAL SULFUR AMINO ACID REQUIREMENT FOR FINISHING PIGS FED PAYLEAN 1

Standardized Total Tract Digestible Phosphorus Requirement of 25- to 50-lb Pigs

The Effects of Feed Budgeting, Complete Diet Blending, and Corn Supplement Blending on Finishing Pig Growth Performance in a Commercial Environment 1

Effects of Increasing Zn from Zinc Sulfate or Zinc Hydroxychloride on Finishing Pig Growth Performance, Carcass Characteristics, and Economic Return

SWINE DAY. Report of Progress Kansas State University Agricultural Experiment Station and Cooperative Extension Service

Potential for Fish Meal Analog as a Replacement for Fish Meal in Early-Weaned Pig Diets

Determining the Effects of Tryptophan:Lysine Ratio in Diets Containing Dried Distillers Grains with Solubles on Growth Performance of Finishing Pigs 1

Summary. Procedures. (Key Words: Sorghum, Distillers Grains, Waxy, Endosperm, Finishing Pigs.) Introduction

Amino Acid Digestibility and Energy Concentration of Fermented Soybean Meal and Camelina Meal for Swine 1

FOREWORD STANDARD ABBREVIATIONS

Validating a dietary approach to determine amino acid:lysine ratios for pigs

EFFECTS OF INCREASING GLYCEROL AND DRIED DISTILLERS GRAINS WITH SOLUBLES ON THE GROWTH PERFORMANCE AND CARCASS CHARACTERISTICS OF FINISHING PIGS 1,2

C. N. Groesbeck, R. D. Goodband, M. D. Tokach, S. S. Dritz 2, J. L. Nelssen, J. M. DeRouchey, B. W. James, T. P. Keegan, and K. R.

Determining the optimal sampling method to estimate the mean and standard deviation of pig body weights within a population

Transcription:

Kansas Agricultural Experiment Station Research Reports Volume 0 Issue 10 Swine Day (1968-2014) Article 1129 2007 Effects of varying creep feeding duration on proportion of pigs consuming creep feed and preweaning performance R C. Sulabo E J. Wiedemann J Y. Jacela Michael D. Tokach See next page for additional authors Follow this and additional works at: http://newprairiepress.org/kaesrr Part of the Other Animal Sciences Commons Recommended Citation Sulabo, R C.; Wiedemann, E J.; Jacela, J Y.; Tokach, Michael D.; Nelssen, Jim L.; DeRouchey, Joel M.; Goodband, Robert D.; and Dritz, Steven S. (2007) "Effects of varying creep feeding duration on proportion of pigs consuming creep feed and pre-weaning performance," Kansas Agricultural Experiment Station Research Reports: Vol. 0: Iss. 10. https://doi.org/10.4148/2378-5977.6969 This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 2007 Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. Brand names appearing in this publication are for product identification purposes only. K-State Research and Extension is an equal opportunity provider and employer.

Effects of varying creep feeding duration on proportion of pigs consuming creep feed and pre-weaning performance Abstract A total of 54 sows (PIC Line 1050) and their litters were used in this study to determine the effects of varying durations of creep feeding on the rate of pigs consuming creep feed (eaters) and pre-weaning performance. Two groups of sows were blocked according to parity and date of farrowing and allotted to three experimental treatments using a randomized complete block design. Creep feeding was initiated at d 7, 14, and 18 from birth for a duration of 13, 6, and 2 d of creep feeding. A creep diet (1,585 kcal ME/lb, 1.56% TID Lys) with 1.0% chromium oxide was offered ad libitum until weaning (d 20) using a rotary creep feeder with hopper. A single lactation diet (1,586 kcal ME/lb, 0.97% TID Lys) was used where sows were allowed free access to feed throughout lactation. Piglets were weighed individually at d 0 (birth), 7, 14, 18, and 20 to calculate total and daily gains. Daily creep feed intake per litter was recorded and calculated. Fecal samples from all piglets were taken twice per sampling day using sterile swabs at d 14, 18, and 20 for Treatment 1; at d 18 and 20 for Treatment 2; and d 20 for Treatment 3. Piglets were categorized as â eatersâ when fecal sample was colored green at least once on any of the sampling days. Overall, there were no differences in weaning weights (P<0.61), total gain (P<0.38), and daily gain (P<0.38) among pigs and litters fed creep for different durations. Total creep feed intake of litters fed creep for 13 and 6 d were greater (P<0.0001) than those litters provided creep feed for 2 d. There were no differences (P<0.69) in overall creep intake between litters fed for 13 and 6 d. Litters provided with creep feed for 13 d produced 10% more (80 vs. 70%; P<0.03) eaters than litters fed creep for both 6 and 2 d. There were no differences (P<0.98) in the percentage of eaters between litters fed creep for 6 and 2 d. In conclusion, longer durations of creep feeding did not affect pre-weaning gain and weaning weights but did increase the proportion of eaters in whole litters; however, a relatively high percentage of pigs (70%) were classified as eaters by providing creep feed for only 2 d prior to weaning.; Swine Day, 2007, Kansas State University, Manhattan, KS, 2007 Keywords Kansas Agricultural Experiment Station contribution; no. 08-121-S; Swine day, 2007; Report of progress (Kansas State University. Agricultural Experiment Station and Cooperative Extension Service); 985; Swine; Feed management; Creep feeding; feeding duration Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 License. Authors R C. Sulabo, E J. Wiedemann, J Y. Jacela, Michael D. Tokach, Jim L. Nelssen, Joel M. DeRouchey, Robert D. Goodband, and Steven S. Dritz This Research Report article is available in Kansas Agricultural Experiment Station Research Reports: http://newprairiepress.org/ kaesrr/vol0/iss10/1129

Swine Day 2007 EFFECTS OF VARYING CREEP FEEDING DURATION ON PROPORTION OF PIGS CONSUMING CREEP FEED AND PRE-WEANING PERFORMANCE R. C. Sulabo, M. D. Tokach, E. J. Wiedemann, J. Y. Jacela 1, J. L. Nelssen, S. S. Dritz 1, J. M. DeRouchey, and R. D. Goodband Summary A total of 54 sows (PIC Line 1050) and their litters were used in this study to determine the effects of varying durations of creep feeding on the rate of pigs consuming creep feed (eaters) and pre-weaning performance. Two groups of sows were blocked according to parity and date of farrowing and allotted to three experimental treatments using a randomized complete block design. Creep feeding was initiated at d 7, 14, and 18 from birth for a duration of 13, 6, and 2 d of creep feeding. A creep diet (1,585 kcal ME/lb, 1.56% TID Lys) with 1.0% chromium oxide was offered ad libitum until weaning (d 20) using a rotary creep feeder with hopper. A single lactation diet (1,586 kcal ME/lb, 0.97% TID Lys) was used where sows were allowed free access to feed throughout lactation. Piglets were weighed individually at d 0 (birth), 7, 14, 18, and 20 to calculate total and daily gains. Daily creep feed intake per litter was recorded and calculated. Fecal samples from all piglets were taken twice per sampling day using sterile swabs at d 14, 18, and 20 for Treatment 1; at d 18 and 20 for Treatment 2; and d 20 for Treatment 3. Piglets were categorized as eaters when fecal sample was colored green at least once on any of the sampling days. Overall, there were no differences in weaning weights (P<0.61), total gain (P<0.38), and daily gain (P<0.38) among pigs and litters fed creep for different durations. Total creep feed intake of litters fed creep for 13 and 6 d were greater (P<0.0001) than those litters provided creep feed for 2 d. There were no differences (P<0.69) in overall creep intake between litters fed for 13 and 6 d. Litters provided with creep feed for 13 d produced 10% more (80 vs. 70%; P<0.03) eaters than litters fed creep for both 6 and 2 d. There were no differences (P<0.98) in the percentage of eaters between litters fed creep for 6 and 2 d. In conclusion, longer durations of creep feeding did not affect pre-weaning gain and weaning weights but did increase the proportion of eaters in whole litters; however, a relatively high percentage of pigs (70%) were classified as eaters by providing creep feed for only 2 d prior to weaning. (Key words: feed management, creep feeding, feeding duration.) Introduction The plethora of evidence on the benefits of creep feeding has been limiting and equivocal, especially for weaning ages less than four weeks. However, recent studies where piglets were categorized into eaters and non-eaters of 1 Food Animal Health and Management Center, College of Veterinary Medicine. 38

creep feed have provided some new insights on the value of creep feeding. Research at Kansas State University has shown that creep feeding for 18 d improved piglet survivability but did not improve pre-weaning gains or weaning weights at d 20. When whole litters where divided based on creep feed consumption category, piglets designated as eaters had better post-weaning gains and d 28 weights compared to non-eaters and non-creep fed pigs. In this study, about 60% of the creep-fed pigs were categorized as eaters while 75% of creep feed intake was consumed in the last week prior to weaning. It is not known if providing creep feed at varying durations will create more eaters or affect pre-weaning performance. Therefore, the objective of this experiment was to determine the effects of varying durations of creep feeding on the rate of creating eaters and pre-weaning performance. Procedures A total of 54 sows (PIC Line 1050) and their litters were used in this study conducted at the Kansas State University Swine Research and Teaching Center farrowing facilities. Sows used in this experiment were from two batches of sows farrowed in April and May, 2007, with 27 experimental sows included from each batch. Sows were blocked according to parity and date of farrowing and allotted to three experimental treatments using a randomized complete block design. Crossfostering was performed within 48 h postfarrowing to standardize litter weights and litter size (>12 pigs). The sow or litter was the experimental unit with 18 replicates per treatment group. There were three experimental treatments in this study according to the duration of creep feeding. Creep feeding was initiated at d 7, 14, and 18 from birth for Treatments 1, 2, and 3, respectively. These corresponded to durations of 13, 6, and 2 d of creep feeding. A creep diet (1,585 kcal ME/lb, 1.56% TID Lys; Table 1) with 1.0% chromium oxide was offered ad 39 libitum until weaning using a rotary creep feeder (Rotecna Mini Hopper Pan, Rotecna SA, Spain). The feeder is equipped with a 6- liter capacity hopper, which is adjustable to five different settings of feeder gaps to allow ad libitum feeding. The creep diet was in pellet form (2-mm pellets). A single lactation diet (1,586 kcal ME/lb, 0.97% TID Lys) was used in the experiment. Sows were allowed free access to feed throughout lactation. Water was made available at all times for both sows and their litters using nipple drinkers and bowls, respectively. Piglets were weighed individually at d 0 (birth), 7, 14, 18, and 20 (weaning). Creep feeders were weighed daily. Daily creep feed consumption per litter was computed as the difference in feeder weights between consecutive days. Fecal samples from all piglets were taken using sterile swabs at d 14, 18, and 20 for Treatment 1; at d 18 and 20 for Treatment 2; and d 20 for Treatment 3. The color of each fecal sample was visually determined. Fecal sampling was performed twice per sampling day. Piglets that tested negative on the first fecal sampling were re-sampled after 9 to 12 h. Piglets were categorized as eaters when fecal color was green at least once on any of the sampling days. Sows were weighed after farrowing and at weaning. Weekly feed intake of the sows was recorded to calculate total and average daily feed intake. In this study, two sows from Treatment 3 were removed from the test due to death of the sow. General health of the piglets was checked daily and use of medication was monitored. Temperature in the farrowing facility was maintained at a minimum of 20 C, and supplementary heat was provided to the piglets using heat lamps when needed. Periodic and cumulative average daily gain and creep feed intake were calculated for each treatment group. Pre-weaning mortality was also calculated. Data were analyzed as a randomized complete block design using

PROC MIXED of SAS. The effect of varying creep feeding durations on percentage of eaters was analyzed using the Chi-square test in SAS. Results and Discussion The effect of varying creep feeding durations on sow performance is shown in Table 2. Sows had an average parity of 2.1 ± 0.2 and lactation length of 19.9 ± 0.3 d. Varying the duration of creep feeding had no effect on total (P<0.76) or daily feed intake (P<0.53) of sows during lactation. Likewise, there were no differences in post-farrowing weight (P<0.98), weaning weight (P<0.74), and lactation weight loss (P<0.67) among the treatments. Litter size at weaning (P<0.98) and mortality from d 2 to weaning (P<0.93) was also similar across the treatments. Overall, differences in litter weaning weights (P<0.80), total gain (P<0.50), and daily gain (P<0.52) among litters fed creep for different durations were not significant (Table 3). For individual pigs, differences in weaning weight (P<0.61), total gain (P<0.38), and average daily gain (P<0.38) among creep-fed litters for different durations were also not significant (Table 4). These results suggest that the availability of creep feed for longer durations did not improve weaning weights and weight gains of both pigs and litters. This may be due to the relatively small creep feed intake during the first week of creep feeding; intake may have been insufficient to generate any differences in growth performance. From d 8 to 14, litters offered creep feed for 13 d had a total intake of 0.36 lb (Figure 1). From d 15 to 20, litters fed creep for 6 d had a higher (P<0.02) total creep intake than litters fed creep for 13 d. Likewise, litters provided with creep feed for 6 and 2 d also tended (P<0.09) to have higher total creep intake than litters fed creep for 13 d. Overall, the total creep feed intake of litters fed for 13 and 6 d were greater (P<0.0001) than those litters provided creep feed for only 2 d (Figure 1). There were no differences (P<0.69) in total creep intake between those fed for 13 and 6 d. These results suggest that initiating creep feeding at a later age does not detrimentally affect creep intake; instead, older piglets readily accept creep feed and consume the same or more feed than piglets started on creep feed at an earlier age. Thus, litter creep intake seems to be more related to the maturity of piglets rather than the period of induction of creep feeding. The duration of creep feeding influenced (P<0.03) the proportion of eaters in creep-fed litters (Figure 2). Litters provided with creep feed for 13 d produced 10% more (P<0.03) eaters than litters fed creep for both 6 and 2 d. There were no differences (P<0.98) in the percentage of eaters between litters fed creep for 6 and 2 d. The higher rate of eaters suggests that the longer availability of creep feed to litters helps stimulate more piglets to consume creep feed and improves the average creep consumption of piglets categorized as eaters. However, a 10% difference in eaters also indicates that the additional 7 to 11 d of creep feeding generated only 1 more eater per litter (for a litter of at least 10 piglets). Therefore, the benefit of longer durations of creep feeding should be weighed based on the economic value of creating more eaters in whole litters. In conclusion, longer durations of creep feeding do not affect pre-weaning gain and weaning weights but can increase the proportion of eaters in whole litters. The adoption of longer creep feeding durations should be evaluated based on practicality and the economic benefits of improved piglet performance attributed to eaters post-weaning. 40

Table 1. Diet Composition (as-fed basis) Ingredient, % Creep a Lactation b Corn 6.15 60.00 Soybean meal (46.5% CP) 2.32 31.20 Spray dried whey 25.00 - Fine ground oat groats 30.00 - Extruded soy protein concentrate 10.00 Spray-dried animal plasma 6.00 - Select menhaden fish meal 6.00 - Lactose 5.00 Choice white grease 5.00 5.00 Monocalcium P (21% P) 0.35 1.45 Chromium oxide 1.00 - Antibiotic 1.00 Limestone 0.45 1.20 Zinc oxide 0.38 - Salt 0.30 0.50 L-Lysine HCl 0.15 - DL-methionine 0.15 - Trace mineral premix 0.15 0.15 Vitamin premix 0.25 0.25 Sow add pack - 0.25 Acidifier 0.20 - Flavor 0.10 - Vitamin E, 20,000 IU 0.05 - Total 100.00 100.00 Calculated analysis Crude protein, % 23.9 19.6 TID Lysine, % 1.56 0.97 ME, kcal/lb 1,585 1,589 Calcium, % 0.79 0.87 Available P, % 0.56 0.38 TID Lysine:ME ratio, g/mcal 4.47 2.77 a Diet fed in pellet form. b Diet fed in meal form throughout lactation. 41

ab Table 2. Effects of Varying Creep Feeding Durations on Sow Performance Creep Feeding Duration, d Item 13 6 2 SED Probability, P< No. of sows 18 18 16 - - Lactation length, d 19.7 19.9 20.0 0.2 0.33 Average parity 2.1 2.1 2.2 0.2 0.95 Lactation feed intake, lb Total (d 0 to 20) 225 223 231 14.5 0.76 ADFI 11.4 11.2 11.5 0.7 0.53 Sow weight, lb Post-farrowing 480 482 482 14.5 0.98 Weaning 445 450 456 14.5 0.74 Change -34.7-32.1-27.7 7.9 0.67 No. of pigs/litter Post-fostering 12.2 12.3 12.2 0.1 0.51 D 20 (weaning) 11.2 11.3 11.2 0.3 0.98 Mortality (d 2 to 20), % 7.7 7.9 8.6 2.3 0.93 a Two groups of sows (total =52, PIC Line 1050) were blocked according to day of farrowing and parity and allotted to three treatments (13, 6, and 2 d creep feeding durations). b Creep feed with 1.0% chromium oxide was offered ad libitum from d 7, 14, and 18 to weaning (20 d). 42

Table 3. Effects of Varying Creep Feeding Durations on Litter Performance ab Creep Feeding Duration, d Item 13 6 2 SED Probability, P< No. of litters 18 18 16 - - No. of pigs 219 221 197 - - Litter weight, lb Post-fostering 34.0 34.2 33.9 1.0 0.97 D 7 60.4 60.8 60.6 2.7 0.99 D 14 102.0 100.1 99.8 5.1 0.89 D 18 129.0 127.1 125.7 6.1 0.86 At weaning 141.2 138.1 137.0 6.6 0.80 Litter BW gain, lb D 8 to 14 41.7 39.4 38.9 2.8 0.55 D 15 to 18 27.0 27.0 25.9 1.6 0.75 D 19 to 20 12.2 11.0 11.2 1.0 0.41 D 15 to 20 39.2 38.0 37.2 2.2 0.65 D 8 to 20 80.9 77.3 76.0 4.4 0.50 Litter ADG, lb D 8 to 14 5.96 5.62 5.55 0.40 0.55 D 15 to 18 6.75 6.76 6.45 0.41 0.75 D 19 to 20 6.56 6.33 6.20 0.37 0.62 D 15 to 20 6.14 5.51 5.65 0.50 0.41 D 8 to 20 6.22 5.96 5.85 0.34 0.52 a Two groups of sows (total =52, PIC Line 1050) were blocked according to day of farrowing and parity and allotted to three treatments (13, 6, and 2 d creep feeding durations). b Creep feed with 1.0% chromium oxide was offered ad libitum from d 7, 14, and 18 to weaning (d 20). 43

Table 4. Effects of Varying Creep Feeding Durations on Pig Performance ab Creep Feeding Duration, d Item 13 6 2 SED Probability, P< No. of litters 18 18 16 - - No. of pigs 219 221 197 - - Pig weight, lb Post-fostering 3.05 3.04 3.04 0.07 0.97 D 7 5.40 5.40 5.40 0.17 0.99 D 14 9.13 8.89 8.94 0.36 0.78 D 18 11.55 11.29 11.24 0.44 0.75 At weaning 12.66 12.26 12.26 0.47 0.61 Pig BW gain, lb D 8 to 14 3.73 3.49 3.54 0.22 0.49 D 15 to 18 2.42 2.39 2.3 0.14 0.68 D 19 to 20 1.11 0.97 1.02 0.08 0.19 D 15 to 20 3.53 3.37 3.32 0.18 0.46 D 8 to 20 7.26 6.86 6.86 0.34 0.38 Pig ADG, lb D 8 to 14 0.533 0.499 0.506 0.031 0.49 D 15 to 18 0.605 0.598 0.574 0.036 0.68 D 19 to 20 0.556 0.487 0.511 0.039 0.19 D 15 to 20 0.589 0.561 0.553 0.030 0.46 D 8 to 20 0.559 0.527 0.528 0.026 0.38 a Two groups of sows (total =52, PIC Line 1050) were blocked according to day of farrowing and parity and allotted to three treatments (13, 6, and 2 d creep feeding durations). b Creep feed with 1.0% chromium oxide was offered ad libitum from d 7, 14, and 18 to weaning (d 20). 44

Litter Litter creep creep feed feed intake intake (lb) (lb) 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.36 13 d 6 d 2 d 1.64b 1.64 a a 1.49 a 1.13 0.78b0.77b 0.77 b a 0.56 0.2 0.0 d 8-14 d 15-20 d 19-20 d 8-20 a,b P <0.09; Ave SEM = 0.11 Day after birth Figure 1. Effect of Varying Creep Feeding Durations on Total Litter Creep Feed Intake. 90 80 70 80.2 a (162) 70.0 b (142) χ 2 = 6.79; Duration effect (P <0.034) SEM = 4.77 70.6 b (127) Percent eaters 60 50 40 30 20 19.8 a (40) 30.0 b (61) 29.4 b (53) Eaters Non-eaters 10 0 13 6 2 Creep feeding duration, d Figure 2. Effect of Varying Creep Feeding Durations on Percentage of Eaters (number of pigs in parentheses). 45