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Sixty-four gilts, average initial weight of about 120 kg, were used to evaluate the use of Distillers Dried Grains with Solubles (DDGS) as a replacement for soybean meal in a corn:soybean meal diet fed during gestation. Dietary levels of DDGS were 0, 17.7 and 44.2%, with all diets containing about .42% (calculated) lysine. Two gilts from each treatment were used in a nitrogen balance determination during the 84th through the 88th day of gestation.Average gestation gain, litter size and weight at birth were similar for all dietary treatments. During lactation all sows received a fortified 16% crude protein diet. Litter size and weight at weaning (28 days) and sow weight change were similar for all groups.Grams of nitrogen retained per day, 84th through the 88th day of gestation, did not differ significantly among diets. Percent of dietary nitrogen retained was lower (P<.05) from the 17.7 and 44.2% DDGS diets than from the control diet, which likely reflects the deamination of excess amino acids in the DDGS diets.These results show that DDGS can replace soybean meal on a lysine-equivalent basis as a source of supplemental amino acids in diets for gestating swine.

Thirty-six crossbred gilts 10 months of age were bred and assigned to dietary magnesium levels of 400 or 900 ppm. At parturition the levels were modified to 150 and 650 ppm. During lactation phosphorus levels of .30 or .54% were fed within each magnesium level. Magnesium levels did not influence the number or weight of pigs at birth or weaning. Sows fed the high level of magnesium (650 ppm) maintained equilibrium in magnesium balance (corrected for losses in feces, urine and milk) while sows on low magnesium evidenced a severe negative balance. The sows were in negative balance on most treatments for calcium, phosphorus and potassium. The magnesium in serum, ribs and turbinates was lower after a 36-day lactation in sows fed the low level of magnesium.

Five experiments involving 150 pigs were conducted to evaluate the effect of roasting temperatures on the nutritive value of corn for swine. Roasting temperatures of 80, 100, 120, 140 and 160 C showed no effect on crude protein, lysine, ether extract, ash, acid detergent fiber and gross energy contents of the regular corn (yellow hybrid). Moisture content and test weight decreased linearly while percent starch gelatinization increased with increase in temperature.Growing pigs showed a preference for the 100 C corn, 34.1% of total corn eaten, when given free-choice cafeteria access to all corns. Second choice (20.2% of total consumed) was regular nonroasted corn.In a balance study with finishing pigs, there was a significant beneficial quadratic effect of roasting temperature on metabolizable energy as percent of energy absorbed (MEA), nitrogen retained (NR) and NR as % of nitrogen absorbed (NRA). Pelleting the diets significantly decreased NR and NRA.In finishing swine roasted (100 C) corn produced comparable gains (ADG), nonsignificantly decreased feed intake (ADF) and significantly improved gain/feed (G/F) compared to nonroasted corn.Roasting (100 C) opaque-2corn, however, nonsignificantly depressed ADG, ADF and G/F. Carcass characteristics were not significantly affected by diet fed.When regular or roasted (100 C) normal corns were fed as energy sources in diets for young pigs, ADF was significantly higher with 100 C corn. When the corns were fed as the only source of protein, roasting (100 C) had no significant effect.

The protein content of 18 samples of commercially grown opaque-2 corn obtained from various areas in Illinois was 8.9 ± .17% and the lysine content was .33 ± .01% (mean ± SEM and based on 90% dry matter). For 30 samples of commercially grown opaque-2 corn obtained from various areas in Virginia in 1973, the protein content was 8.37 ± .07% and the lysine content was .37 ± .01%. For 26 samples of opaque-2 corn obtained in Virginia in 1974, the protein content was 8.61 ± .17% and the lysine content was .36 ± .01%. The protein content of 10 samples of normal corn obtained in Virginia in 1973 was 8.72 ± .24% and the lysine content was .25 ± .01%. The protein content of 18 samples of normal corn obtained in Virginia in 1974 was 8.52 ± .22% and the lysine content was .27 ± .01%. There was a positive linear relationship between protein (X) and lysine (Y) content of opaque-2 corn: Y = .037X + .002 (r = .62; P<.01) for Illinois; Y = .044X − .002 (r = .59; P<.01) for Virginia in 1973; and Y = .032X + .084 (r = .80; P<.005) for Virginia in 1974. There was no relationship between protein and lysine content of normal corn in 1973 with only a weak relationship (P<.05) in 1974.Results of three feeding trials using opaque-2 corn grown commercially in Virginia indicate that the lysine in opaque-2 corn is as available for growing pigs as the lysine in normal corn and that feedlot performance is directly related to the lysine content of the corn.

Throughout the past quarter century the successful hog producers have been those who based production decisions on the potential for net returns from their enterprise. Their quest for improved labor efficiency led to mechanization that, in turn, necessitated redesign and enlargement of facilities to make optimum use of equipment. To support the resulting increase in capitalization required additional improvements in labor efficiency and thus, a seemingly endless cycle was born. From this cycle has come a tangible economic benefit for consumers of this continent who have seen a steady decline in the ratio of pork costs with their hourly income. Today, the North American public requires fewer working hours to buy pork than occurs in any other area of the world. For pork producers, however, the economic benefits accruing from the cycle have been transitory with net returns from their enterprise remaining relatively constant. The emphasis given to improved labor efficiency has tended to obscure the fact that feed, not labor, is the largest single component of production costs. The efficiency of feed conversion is not a function of labor efficiency or scale of operations, but it is directly related to the reproductive efficiency of the sow herd (whose maintenance represents a substantial portion of the total feed budget) and management-related problems such as disease control and feed wastage, and to the amount of energy-expensive fat carried by the pigs marketed. In this latter context, the economic message that can be conveyed by an appropriate carcass classification system goes far beyond its potential for improving carcass merit and thereby enhances the consumer image of pork. It also enhances processing efficiency by providing more units of edible product/unit of labor in carcass preparation and reduces transport costs/unit of edible product. Most important, however, is the improvement in the efficiency of feed conversion that results from a reduction in excess fat. None of these benefits, least of all the potential for reducing feed costs/unit of product, can be ignored by the industry.

The apparent metabolizable energy (ME) content of condensed fermented corn solubles with germ meal and bran (DSLC) was determined in a series of trials with growing pigs and gravid and nongravid female swine. DSLC was substituted for 10 or 20% of a fortified corn-soybean meal basal diet.Estimated ME corrected for nitrogen balance was 3.79 kcal/g dry matter. Metabolizable energy as determined using gravid females tended to be higher than that found in growing pigs or nongravid females. Nitrogen retention was depressed with each increment of dietary DSLC. Concomitant increases occurred in urinary and fecal nitrogen levels suggesting both poor amino acid pattern and protein digestibility.

A combination of sodium caseinate and sweet dried whey was compared to dried skim milk as a protein source for artificially reared piglets. Rate and efficiency of gain, diet consumption, frequency of diarrhea, nutrient balance and characteristics of the gastrointestinal tract and its contents were observed in piglets fed these protein sources. Rats were fed the same protein sources with rate and efficiency of gain, diet consumption, and frequency and severity of diarrhea observed. The combination of sodium caseinate and sweet dried whey was inferior to dried skim milk as a protein source for artificially reared piglets, the rate of gain being only 80 to 83% as fast for the group fed the casein-whey diet as for those fed the dried skim milk diet. Rats responded similarly. In both species the depressed rate of gain on the casein-whey diets was associated with more frequent diarrhea. Balance data did not show the dried skim milk diet to be superior, but reliable fecal collections could not be obtained from severely scouring piglets. No treatment differences were observed in the pH of the gastrointestinal tract contents, weight of empty stomach or histology of the gastrointestinal tract. Weight of stomach contents was greater in piglets fed the casein-whey diet.

Peptonized milk, a tryptic digest of skim milk, proved unacceptable as a protein source for artificially reared piglets. When this product was substituted for dried skim milk, rate and efficiency of gain were sharply decreased and incidence and severity of diarrhea markedly increased. Rectal temperature was decreased. The difference in nutritional adequacy of the diets, measured by a chick growth study, was not nearly sufficient to explain the differences in piglet performance. Therefore, these results support the hypothesis that some component(s) of milk is important to the piglet for reasons other than classical nutrient content.

Egg white proved to be an unsatisfactory protein source for artificially reared piglets. Rate of gain and gain/feed were depressed, while incidence and severity of diarrhea and in some trials mortality were greater among piglets fed a diet based on egg white compared to those fed a dried skim milk diet. The same two protein sources were compared in diets of rats beyond the early suckling stage, to determine whether the effects seen in piglets are specific either for the early suckling period or for the porcine species. Rat performance did not differ between the two protein sources. It is suggested that for maximum performance piglets may require certain physiologically active components of milk not explainable in terms of classical nutrient content. Addition of immunoglobulins isolated from serum from market-weight swine was without effect for either piglets or rats.

Five experiments were conducted to evaluate the effects of (1) roasting and roasting temperatures (corn temperature of 82, 104, 127 and 140 C) and (2) pelleting of diets upon the nutritive value of high-moisture (23%) corn for swine. No effect of temperature treatment on content (dry matter basis) of crude protein, lysine, ether extract, ash, acid detergent fiber and gross energy was observed, but gelatiniza-tion increased and test weight decreased with increase in temperature.Growing pigs performed similarly on diets containing corn roasted at the different temperatures. Finishing pigs showed a significant linear decrease in feed intake (ADF) with increase in corn temperature. There was a beneficial effect of 82 and 104 C treatments on gain/feed (G/F). Pelleting the diets significantly decreased ADF and improved G/F of both growing and finishing swine.Growing pigs showed a linear increase in apparent energy absorbed (AEA), metaboliz-able energy (ME) and corrected metabolizable energy with increase in corn temperature treatment. There was a beneficial quadratic effect of temperature treatment on nitrogen retained (NR) and NR as percent of absorbed (NRA).With finishing pigs, the NR and NRA values were higher from the 104 C corn diets than from the other roasted-corn diets.Pelleting the diet increased AEA, ME, CME and ANA for the growing pigs, and AEA, ME, CME, ANA, NR and NRA for the finishing pigs.

One hundred and twelve gilts were bred and assigned to gestation treatments in which they were fed a corn-soybean meal diet (.33% P) with no supplemental phosphorus or sufficient dicalcium phosphate to give a total of .68% dietary phosphorus. At parturition the sows within each gestation treatment were rendomly assigned to dietary treatments of a corn-soybean meal diet fortified to contain .45, .55 or .65% phosphorus for a 28-day lactation. Low dietary phosphorus did not significantly reduce litter size at birth or weaning, weight gain to weaning, sow weight gain during gestation or lactation, milk production or composition, or sow bone calcium or phosphorus. Lactating sows fed .45% phosphorus digested and retained less phosphorus than did sows on the other two treatments. Although bone ash values were high for all sows after lactation, the sows fed .45% phosphorus had significantly lower values. With sows on tests through one litter the unsupplemented diet (.33% P) was adequate during gestation and .45% phosphorus proved to be adequate during lactation. The reduced bone ash observed in sows fed the lowest level of phosphorus suggests that sows retained for multiple parities may require increased phosphorus for greater bone strength.

Three experiments involving 200 pigs were designed to determine the value of corn solubles with germ meal and bran (DSLC) as an amino acid source when substituted for part of the corn and soybean meal. In each of these studies, diets were formulated to meet the lysine requirement, based on the initial weight of the pigs.For young pigs DSLC was substituted to provide up to 30% of the total lysine in the diet. Performance at the highest level was equal to that of the pigs fed the corn-soybean meal diet. For finishing pigs DSLC was substituted to provide up to 36% of the total dietary lysine. As with the young pig, the performance of finishing pigs fed diets with the upper level of DSLC was similar to that of pigs fed the corn-soybean meal diet. DSLC can be considered an effective amino acid supplement for cereal grains when used at levels tested in these studies.

Five experiments were conducted with 282 finishing pigs to evaluate the use of condensed fermented corn solubles with germ meal and bran as an amino acid source for swine. This wet milling byproduct referred to as dried steep liquor concentrate (DSLC) is becoming a major byproduct of the industry as methods of corn processing change. DSLC serving as the only amino acid supplement for corn supported much lower gain and efficiency in finishing pigs than did a corn-soybean meal diet. In corn-DSLC diets designed to meet the requirements for lysine and tryptophan performance could not be markedly improved by supplementing with either of the two amino acids singly. However, performance was greatly improved when both amino acids were added to the diet. The experiments clearly demonstrate that lysine and tryptophan in DSLC have limited biological availability.

Studies were conducted to investigate the nutritive value and palatability of ensiled broiler litter and corn forage for ruminants. Corn forage, cut at two stages of maturity, was ensiled untreated, with .5% urea (wet basis), and with levels of litter to supply 15 and 30% of the total dry matter. All mixtures appeared to ensile properly. The silages were fed to sheep in two metabolism and two palatability trials to study digestibility, nitrogen utilization and voluntary dry matter intake.The dry matter, crude protein and ash were higher for the ensiled mixtures containing broiler litter for both maturities. Dry matter digestibility averaged 64.5% and was similar for all silages. Apparent digestibility of crude protein was depressed by the later stage of maturity of the corn plant (57.1 vs48.0% for control silages) and was increased by each level of litter addition. Nitrogen retention data indicated that litter nitrogen was well utilized; however, increasing the level of litter from 15 to 30% of the silage dry matter tended to depress efficiency of dietary nitrogen utilization. Voluntary dry matter intake was higher for silages containing broiler litter than for control and urea silages. Average daily dry matter consumption was 848 g for the control silages, 925 g for the urea treated silages, and 1,445 and 1,464 g for the silages containing 15 and 30% broiler litter, dry basis, respectively.

The objectives of the research were to study fermentation characteristics and microbial concentration of ensiled mixtures of different ratios of broiler litter and corn forage harvested at two stages of maturity. Corn forage harvested at each stage of maturity was ensiled with broiler litter supplying 15, 30 and 45% of the total dry matter of ensiled mixtures. Untreated forage and forage containing .5% urea, wet basis, were also ensiled. Mixtures were ensiled in small polyethylene bags containing 2 kg of initial material or in large bags containing 114 kg of initial material. Samples representing litter, initial forage, initial mixtures and silages were analyzed for various components. Plate counts for total bacteria and coliforms were conducted on the small-bag silages.All mixtures preserved well and appeared to show typical fermentation characteristics. Percent dry matter in silage was significantly increased by advancing maturity of corn forage and by each level of litter addition.

An initial study was conducted with 37 crossbred sows to compare the efficacy of dicalcium, soft and Curacao phosphates as supplements for a corn-soybean meal diet during gestation and lactation. Reproductive performance was similar whether the gilts received the diet unsupplemented or supplemented with one of the three phosphorus supplements. There was a high incidence of posterior paralysis during the sixth to eighth week of lactation in sows fed the unsupplemented diet. Paralysis was also observed, but to a lesser incidence, in sows fed soft or Curacao phosphates.Reproductive performance was not significantly (P< .05) affected in a second study with 70 first-litter sows fed the same diets. During the 36-day lactation, phosphorus digestibility, retention and balance (corrected for milk phosphorus) were similar for sows fed the supplemented diets but much lower for those fed the basal diet. Bone ash and phosphorus and bone strength criteria were lower for sows fed the unsupplemented diet than for those fed dicalcium or Curacao phosphate. Values for sows fed soft phosphate were intermediate between the unsupplemented group and those receiving the other supplements. Two sows on the unsupplemented diet developed posterior paralysis after the litter was weaned and the sows were grouped. A phosphorus level of 0.5% during gestation and lactation appears adequate for all criteria measured when feeding either dicalcium or Curacao phosphate.

An experiment was conducted to determine the amount of 1 N sulfuric acid required to lower the pH of broiler litter from an initial pH of about 8 to a final pH of about 6, and to evaluate the effect of acidification of litter on nitrogen loss from dry heat. Approximately 30 ml of 1 N acid were required per 100 g of litter. Nitrogen loss during heat treatment (4 hr. at 150 C) was reduced about 50% when litter was acidified to a pH of 6 prior to heating.Two metabolism trials were conducted to study the effects of different methods of processing broiler litter on digestibility and nitrogen utilization by lambs. The isonitrogenous rations differed in the source of supplemental nitrogen. Autoclaved litter, dry heat litter, acid plus dry heat litter and soybean meal supplied equal amounts of nitrogen in four respective rations. Supplementary nitrogen sources were estimated to supply 50% of the total dietary nitrogen.

Three studies were conducted with 86 litters containing 807 pigs to evaluate two methods of iron dextran administration and the affect of type of floor. Iron dextran was shown to be effective as a hematinic for 28 days whether injected intramuscularly or administered orally within the first 12 hr. of life, prior to closure of the intestine to absorption of large molecules. Pigs farrowed and raised on steel-slatted floors maintained adequate hemoglobin values with no other iron treatment. Pigs managed similarly on steel slats coated with epoxy developed anemia by 14 days.

The effect of time on the distribution and retention of intravenously injected 85Sr was studied in 16 crossbred pigs. Specific activity decreased rapidly in serum, kidney, liver and longissimusmuscle. Metatarsal, turbinate, 10th rib and fibula had similar specific activities at each time determined, reaching peaks at 16 or 32 hr. post injection. The specific activity of the proximal and distal portions of the femur was maximal at 4 and 16 hr., respectively, whereas specific activity of the shaft showed linear increase through the 128-hr. period and was less than the other bone samples. These activity changes for femur ends and shaft reflect the greater metabolic activity in the areas of the epiphyseal cartilage than in the diaphysis. Turbinate 85Sr uptake relative to other bones was less than reported in 45Ca uptake studies. Considering the bones sampled in the present experiment, the proximal portion of the femur appears to be the site of maximum metabolic activity in the skeleton of the young pig. In this experiment both the distribution and retention of 85Sr were time dependent and appeared to reflect the normal physiological growth process.

Twelve castrate male pigs averaging 9.3 kg were used to study effects of ambient temperature on performance and carcass development. Individual littermates were caged in temperature-controlled chambers (7, 23 and 33 C) and fed a fortified 16% crude protein corn-soybean meal diet. Pigs were slaughtered at an average within treatment weight of about 32 kilograms. Feed intake decreased significantly at 33 C and increased significantly at 7 C. Rate of gain decreased significantly at 33 C and gain/feed did not differ significantly among treatments, but pigs at 7 C were least efficient. Cold exposure resulted in significantly decreased carcass length. Lean muscle mass, estimated at 40K count, was significantly greater for pigs at 7 C. Backfat was variable and leaf fat increased as temperature increased. Weight of liver and its content of crude protein and fat increased with decrease in temperature. Kidney weight increased significantly with decreasing temperature but percent moisture, fat and protein did not differ significantly. Crude protein content of the L. dorsimuscle was significantly less at 33 than at 23 and 7 C. Size of the thyroid and adrenal glands decreased as temperature increased.

One-hundred-twenty pigs averaging 30 kg were used in two experiments to study the effect of level and source of phosphorus on turbinate and long bones. Dicalcium phosphate or soft phosphate was added to a cornsoybean meal diet containing 0.34% phosphorus to provide either 0.50 or 0.74% dietary phosphorus. Pigs were slaughtered at 90 kg for serum and bone analysis. Weight gain, serum phosphorus and turbinate and rib ash, calcium and phosphorus values increased with increases in dietary phosphorus, the responses plateauing at 0.50% phosphorus for each of these criteria, Dicalcium phosphate supported more rapid gains than soft phosphate although rib and turbinate ash values were similar for the two sources. Trace mineral composition of turbinates was influenced by level and source of phosphorus. The difference of greatest magnitude was the fluoride content, which was greatly increased in pigs receiving soft phosphate. Histological observations showed no differences related to treatment except that the invasion of turbinates by cartilage was greatest in pigs receiving the phosphorus-deficient diet.

Five farrowings with a total of 269 first-litter gilts were utilized to study effects of source and level of dietary protein fed during gestation on reproductive performance and progeny development. Five experimental diets were evaluated, all fed at 1.9 kg/day throughout gestation. Sources and levels of protein were: corn, 8.8% protein; opaque-2 corn, 9.7% protein and corn-soybean meal mixtures to provide 12, 16 or 20% protein.Dietary treatment during gestation had no effect on number or weight of pigs farrowed (total or live). However, number of pigs weaned/litter, litter gain and total litter weaning weight were less in litters from gilts fed the corn diet as compared with those from gilts fed the other diets. Opaque-2 corn was superior to conventional corn and equal to the corn-soybean meal treatments in these criteria. Gilts fed the corn diet gained less during gestation than gilts on the other treatments, and gilts fed the opaque-2 corn diet gained less than those fed 12, 16 and 20% protein diets. Gilts fed the corn diet during gestation gained 4.5 kg during the 3-week lactation period, but those on the other treatments lost weight in proportion to the weight gained during gestation. Lactation diet intake was similar for all five treatments.

The efficacy of L- and DL-tryptophan conversion to nicotinic acid was measured in young swine receiving corn-based diets formulated just to meet the requirement for tryptophan. The addition of either 0.01% L- or DL-tryptophan or 13.2 ppm nicotinic acid significantly increased rate of gain and improved gain/feed ratio compared to that of pigs fed the unsupplemented diet. Rate of gain and gain/feed were not enhanced by substituting wheat or oats for corn. However, adding 5% wheat bran to the corn diet resulted in performance equal to that from supplemental nicotinic acid. Pigs deficient in nicotinic acid or tryptophan exhibited immunologic responses and serum protein values equivalent to pigs on the complete diet.

One-hundred-thirty-six young swine were used in three experiments to compare the efficacy of ferrous carbonate and ferrous sulfate in purified diets in maintaining normal hemoglobin values. Ferrous carbonate was ineffective as an oral hematinic supporting no higher hemoglobin than found in pigs receiving an unsupplemented purified diet. In a second series of three experiments, 120 young swine were used to study the efficacy of ferrous carbonate when added to a purified diet to give totals of approximately 18, 48, 92 and 147 ppm of iron in the diet. None of these levels supported hemoglobin values greater than the unsupplemented diets. At the conclusion of this phase of these experiments, half of the pigs was changed to diets supplemented with ferrous sulfate. These pigs had significantly greater hemoglobin values after 8 to 11 days on the new regime than the pigs remaining on ferrous carbonate. Weight gain was reduced only for the pigs receiving the unsupplemented diet containing less than 29 ppm iron or the ferrous carbonate supplemented diets. This series of experiments confirms earlier reports that 60 to 80 ppm of iron are adequate for swine ranging from birth to 35 kg. in weight and fed semi-purified diets. The current study confirms that ferrous carbonate is ineffective as an oral hematinic even at levels well in excess of the suggested requirement value.

Eighteen castrate, crossbred male pigs weighing 18 kg. initially were used to study the effects of widely different dietary crude protein levels (16 to 12%, 32% and 48%) on carcass development. Daily weight gain and feed consumption decreased as dietary protein level increased, but gain/feed ratios were similar among diets. As dietary protein level increased dressing percent and back fat thickness decreased, and percent four lean cuts increased. The net quantity of four lean cuts, however, did not differ among diets. The decrease in back fat thickness as dietary protein level increased from 16 to 12 to 32% was five times greater than that which occurred between 32 and 48% protein. The response of loin-eye area to dietary protein level was variable. The contents of moisture, crude protein and crude fat of liver, kidney and loin-eye muscle were determined. Moisture content of liver increased as dietary protein level increased.

Two weight gain assays and one nitrogen retention assay were carried out to evaluate the replacement value of cystine for methionine in the diet of young pigs. An isolated soybean protein diet containing 12.2% protein was supplemented with graded decrements of methionine and graded increments of cystine to provide a total of 0.20% supplementary sulfur-bearing amino acids.Under both group and individual ad libitumfeeding conditions, weight gain was as rapid when 56% of the total sulfur amino acid requirement came from cystine, as when all was supplied by methionine. When equally fed in the nitrogen retention assay, the replacement value of cystine for methionine was 66%. Data from all three assays suggested that above a certain level of replacement (56%), cystine imbalances the diet, causing both reduced feed intake and gain. However, at equal levels of feed intake, maximal performance can be achieved on a diet containing at least 66% of the total sulfur amino acids as cystine.

Three hundred and seventy-two growing-finishing swine were used to study the effects of housing environment on level of performance and carcass development. In each of three successive winter seasons littermate pigs were equally represented in each housing environment: enclosed and heated building, enclosed and unheated building or open-front buildings with a south exposure. In the heated building temperatures ranged from 16 to 24° C. during the growing periods and 10 to 25° C. during the finishing periods. Respective daily average temperatures were 21 and 18° C. Temperatures in the unheated enclosed building ranged from 1 to 24° C, average of about 12° C. Outside ambient temperatures ranged from −24 to 18° C, average of about −3° C. During the growing period (start to 50 kg.) feed intake in the open-front building was greater than that in the heated building. Rate and efficiency of gain, however, decreased with decrease in temperature. Although of lesser magnitude, similar trends were observed with the finishing pig. Differences in performance of pigs in the heated and unheated enclosed buildings varied between years, and the advantage of supplemental heat decreased as weight of animal and ambient temperature increased. In this study, neither physical carcass measurements nor total lean body mass as estimated by 40K count were significantly affected by the housing environments.

Two experiments were conducted with finishing pigs to evaluate diets containing regular corn, Opaque−2corn, milo and wheat.Opaque−2corn, 0.35% lysine, was inadequate as the sole source of amino acids for maximum rate and efficiency of gain in the finishing pig. However, Opaque−2corn plus 0.15% supplemental lysine supported gains and gain/feed equal or superior to those of pigs fed a regular corn-soybean meal 12 fo protein diet. Wheat or milo supplemented with appropriate levels of lysine supported satisfactory gains, but on the average were less efficiently utilized than the Opaque−2-soybean meal and Opaque-2plus lysine diets.Pelleted diets supported more efficient gains than did meal diets.The results reported here indicate that the amino acid pattern of Opaque−2corn is superior to that of regular hybrid corn for finishing swine.

The nicotinic acid requirement of the weanling pig weighing approximately 14 kg. was determined using diets in which the level of yellow corn and the level and source of supplementary protein were varied.Diets containing 0, 40 and 80% yellow corn, 14, 12 and 8% vitamin-extracted casein and 0.10, 0.12 and 0.12% of tryptophan required 11.3, 24.0 and 31.5 ppm of total nicotinic acid, respectively, to support a satisfactory rate and efficiency of gain. A diet containing 80, 10 and 0.19% of yellow corn, vitamin-extracted casein and tryptophan, respectively, required a level of 22.7 ppm of total nicotinic acid to support satisfactory performance. On the other hand, a corn-soybean meal diet containing 16.2% protein, 0.23% tryptophan and 22.5 ppm of total nicotinic acid was not improved by an addition of nicotinic acid.Assuming that the nicotinic acid of yellow corn is largely unavailable to the pig, the minimum requirement is similar at the various levels of corn. However, the need varied indirectly with the level of dietary tryptophan fed in excess of that needed for growth.When tryptophan is fed to meet the requirement, the weanling pig needs approximately 13.2 mg. of available nicotinic acid per kg. of diet.

Corn and soybean meal samples were obtained from 16 different locations in Illinois in each of the years 1965 and 1966. Analyses were made on each sample for dry matter, gross energy, protein, 18 amino acids and 14 minerals. A correlation analysis of protein and individual amino acids for corn and soybean meal separately indicated that within the narrow range of protein values for each feedstuff the correlations were low. Mineral values tended to agree with those reported in the literature except for phosphorus in corn and sodium in both corn and soybean meal which are considerably less than values reported by the National Research Council.

Nitrogen retention was determined for 19 gilts and 17 sows beginning 100 days post coitum. Average weights at 90 days post coitumwere 158 kg. and 191 kg. for gilts and sows, respectively. Diets were formulated to contain levels of crude protein by varying the corn and soybean meal. Corn starch replaced a sufficient amount of corn to formulate the 6% protein diet. Sows and gilts were individually fed 1.9 kg. per day during a 10-day adjustment period and the 5-day collection period. Daily urine and fecal collections were made and representative samples were analyzed for N. At daily protein intakes of 114, 171, 228, 285 and 342 gm. per day, the mean daily N retentions in gm. were 4.23, 8.38, 12.37, 15.64 and 16.28 when the data for gilts and sows were combined. A significant (P<.01) linear increase occurred. Retention appeared to maximize between 15 and 18% protein, or 285 and 342 gm. of protein intake per day, but deviations from linearity were not significant. These data suggest that a daily intake of at least 285 gm. crude protein in such diets is necessary to supply sufficient essential amino acids and amino nitrogen for maximum nitrogen retention in the gravid gilt or sow at 100 days post coitum.

Three trials were conducted with 198 growing pigs to evaluate amino acid additions to a fortified corn diet. Lysine supplementation at 0.2% of the diet caused a marked depression in voluntary feed intake and rate of gain. The same level of supplemental methionine was without effect. Supplemental DL-tryptophan at 0.05% of the diet completely overcame the depression caused by lysine. The data suggest that tryptophan is the first-limiting and lysine the second-limiting amino acid in corn protein and that methionine is not third-limiting.Pigs fed corn diets on pasture performed better than those fed in drylot, particularly when supplemental tryptophan was not provided.

Two experiments were conducted to evaluate the influence of dietary nitrogen source and level on gestation performance of rats exposed to cold. Diets with 5% protein, or 5% protein plus 10 essential amino acids (simulated casein pattern) or glutamic acid or both were fed. Pregnant rats were placed in a 7° or 23° C. environment on the day of mating and fed 18 and 12 gm., respectively. Nitrogen retention for each of five consecutive 4-day periods was determined.At 23° C. supplementation of the basal diet with the essential amino acids increased weight gain. However, at 7° C. weight gain was not significantly affected. At both temperatures the amino acid mixture stimulated nitrogen retention during early gestation (first through fourth day).During the subsequent three 4-day periods, the amino acid mixture stimulated nitrogen retention at 23° C. However, at 7° C. during the same three periods, a positive response was not attained and the levels of nitrogen retained were only slightly above those from the unsupplemented diet at 23° C. The energy intake of the rats at 7° C. may have been inadequate to permit retention of the additional nitrogen consumed. In the final 4-day period (17th through 20th day) nitrogen retention from the amino acid supplemented diets at 7° was equal to that at 23° C. on the diet containing both essential amino acids and glutamic acid. Glutamic acid addition to the diet with essential amino acids increased nitrogen retention at 23° but not at 7° C.

Two group feeding experiments and one individual feeding experiment involving a total of 184 finishing pigs were used to evaluate the effects of dietary dilution with a high-density diluent (sand) or a low-density diluent (cellulose). Under both group and individual feeding conditions sand dilution up to 40% of the diet caused compensatory feed consumption. Weight gain was not depressed until the sand level exceeded 20% of the diet.Feed efficiency was reduced linearly as dietary sand level increased. This occurred in both group-fed and individually-fed pigs. However, utilization of the nondiluent portion of the diet was not affected by sand addition in group-fed pigs, but was improved by sand addition in individually-fed pigs.In the individual feeding study, cellulose dilution up to 40% of the diet produced a linear decrease in gain, feed consumption and feed efficiency; but no differences were observed in gain/feed (less cellulose) ratio.

The relation between graded dietary levels of a single amino acid, at levels from deficient to superoptimal and the level of the same free amino acid in the plasma and to nitrogen balance was studied for lysine, isoleucine, leucine, and histidine.Addition of an amino acid to a diet deficient in that amino acid does not cause a significant increase in its concentration in the plasma at dietary levels less than the dietary need. When superoptimal levels of an amino acid are present in the diet, plasma-free levels of this amino acid increase.The requirements, as a percent of the diet, determined by plasma-free amino acid and nitrogen balance studies, respectively, were: lysine−0.86, 0.81; isoleucine−0.46, 0.53; leucine−0.78, 0.84; and histidine−0.27, 0.25.When pigs were fed graded levels of lysine for only a short period before blood samples were taken, a linear increase in plasma-free lysine was found. This indicates that a period of metabolic adjustment is necessary before plasma-free amino acids can be used to evaluate lysine, and perhaps other amino acid, needs.Plasma-free amino acid values indicated the well-known leucine-isoleucine and valine antagonism at dietary levels of leucine less than that at which the antagonism affected rate of gain or feed intake. At low levels of leucine, plasma free valine was high, but both plasma-free valine and isoleucine were drastically reduced by increasing levels of dietary leucine.

Nitrogen balance experiments were conducted to determine some amino acid needs of pigs weighing about 10 kg. and fed a semi-synthetic diet. Maximum nitrogen retention was the major criterion of response to graded amino acid levels. The pigs were equally fed for a 7-day pre-test period, and urine and feces were collected for the following 5 days.The needs for various amino acids, expressed as percent of the diet, were as follows: isoleucine, 0.67; threonine, 0.60; tryptophan, 0.15; valine, 0.55; and total sulfur-bearing amino acids, 0.74. Further, cystine can replace at least 70% of the need for total sulfur-bearing amino acids. The young pig utilized dietary nitrogen most efficiently when the essential and non-essential amino acids each furnished about 50% of the total dietary nitrogen.A crystalline amino acid diet containing 10.7% protein equivalent and glutamic acid as the sole source of non-essential nitrogen supported nitrogen retention equal to a diet with the same essential amino acid distribution but with 1% casein. Substitution of 10% casein into the amino acid diet and a diet containing 17% casein plus 0.24% methionine supported a greater nitrogen retention by pigs than the amino acid diets. During a 9-day feeding trial young pigs fed the amino acid diet gained 0.34 kg. per day and those fed 17% casein gained 0.42 kg. daily.

Three experiments involving 192 pregnant rats were conducted to determine the influence of temperature on the response to protein levels. Dietary protein levels were 5, 10, 20 and 30% in all experiments. Temperature treatments were 7, 23 or 33° C. in experiments 1 and 2, and 7 and 23° C.in experiment 3. Temperature, protein level and time of initial exposure were observed to have little influence on embryo survival. Weight gain of the dam was less at 7 and 33 than at 23° C. and increased with increasing protein levels except at 33° C.Nitrogen retention of the dam was linearly correlated with protein intake during early gestation. The amount of nitrogen retained by the rats decreased as gestation progressed with rats consuming the high protein diets showing the greatest decline. This decline in nitrogen retention may reflect an increased energy requirement during midgestation.In the latter stages of gestation, the amount of nitrogen retained increased over the preceding period. Nitrogen retention was the greatest in rats fed the 20% protein diet at 23 and 33° C. However, at 7° C. it appeared that consumption of the 20% protein diet did not always support the greatest nitrogen retention. However, feeding the 10% protein diet generally resulted in greater nitrogen retention than feeding the 5% protein diet at all stages of gestation at each temperature.

One hundred seventy growing rats were utilized in 2 experiments (Initial weight 150 and 60 gm.) to evaluate the effect of Na2EDTA in diets ranging to 4510 ppm of iron on calcium and phosphorus balance, bone and blood values. The higher levels of iron reduced gain; gain-feed ratio; bone ash, calcium and phosphorus and serum calcium, but increased serum phosphorus and liver iron.In balance studies urinary phosphorus and percent iron retained were reduced while urinary calcium and iron and fecal phosphorus and iron increased as dietary iron increased.Addition of ethylenediaminetetraacetic acid (Na2EDTA) to the diet increased weight gain and bone ash in the diets containing the high iron levels when calcium was fed at 1.02% (Experiment 1) of the diet, but had little effect when dietary calcium was reduced to 0.59% (Experiment 2). The excretion of fecal phosphorus and fecal ash was reduced and the absorption and retention of phosphorus were increased when Na2EDTA was included in the diet.The increasing urinary excretion of iron and the increased iron retention as evidenced in part by higher liver iron levels indicated that the “mucosal block” was only partially effective in limiting iron absorption. This was further substantiated by the increased iron retention at the highest level of dietary iron.

Three groups of 60 crossbred gilts were employed in two consecutive farrowings to evaluate five gestation protein regimes. Treatments (1.9 kg/day) were: 1) 12% protein corn-soybean meal diet throughout pregnancy, 2) fortified corn diet (8.7% protein) until day 80 of gestation, then 12% protein diet until farrowing, 3) as 2 except a 16% protein corn-soybean meal diet from day 80 until farrowing, 4) 12% protein corn-soybean meal diet with 5% dehydrated alfalfa meal throughout pregnancy and 5) 12% protein corn-soybean meal diet containing 3% menhaden fish meal throughout pregnancy. All dams were ad libitumfed 16% protein corn-soybean meal diets during lactation.Litter size of live pigs at birth and weaning was lower for treatments 2 and 4 than for the average of the other treatments. Reproductive performance of gilts or sows fed the 16% protein diet during the last trimester of pregnancy (treatment 3) was equivalent to that observed on the positive control 12% protein diet fed throughout pregnancy. No improvement was noted from addition of 3% fish meal to the gestation ration.

Four finishing pigs were employed in each of three 4 × 4 latin square designs to study the total sulfur-bearing amino acids, isoleucine and tryptophan requirements. In the total sulfur-bearing amino acids and isoleucine studies graded levels of the test amino acid were added to a 14.1% protein basal diet (protein from corn and gelatin) containing 3,700 kcal metabilizable energy per kilogram. In the tryptophan study the diet contained 13.6% protein and 3,727 kcal metabolizable energy per kilogram. In all studies essential amino acids, excepting the given test amino acids, were provided in concentrations of 1.2 times the published requirements. In each 4 × 4 latin square design four barrows, four dietary treatments and four 10-day periods were employed. There were no significant differences in nitrogen retention among the four periods. Amino acid requirements were determined by the method of least squares. Addition of methionine to a basal diet containing .17% total sulfur-bearing amino acids did not significantly increase nitrogen retention. Expressed as a percent of the diet, estimated requirements for isoleucine and tryptophan were, respectively, .31 ± .01% and .059 ± .001%.

Little information is available on transuterine embryonal migration in monotocous animals and anteroposterior orientation of fetuses in the uterus. This study was designed to determine the frequency of transuterine embryonal migration in sheep and anteroposterior orientation of sheep fetuses, pig fetuses and piglets at birth. The migration frequency of preimplantation sheep embryos was 4.0%. The proportion of sheep fetuses in the anterior presentation position increased from less than 65% early in pregnancy to greater than 90% at 120 days of gestation. Twin fetuses appeared to assume the anterior presentation position earlier in gestation than did singles. Sixty-two percent of piglets were presented anteriorly at birth. Seventy percent of the piglets born in the last half of each litter and 54% of the piglets born in the first half of each litter were presented anteriorly. A greater proportion of piglets was born anteriorly from sows with larger litters than from gilts with smaller litters. In both small and large litters, the proportion of piglets born in the anterior presentation position increased as parturition advanced. Fifty-eight percent of the three fetuses in the segments of each uterine horn nearest the ovaries in gilts killed from 30 to 110 days of gestation were in the anterior presentation position. The proportion for the remaining fetuses near the cervix was 48%. Likewise, in unilaterally ovariectomized gilts, more fetuses in the ovarian segments than in the cervical segments of both uterine horns were in the anterior presentation position. Apparently the distance traveled by the embryo from the ovary during transuterine migration has no effect on fetal anteroposterior orientation in the pig.

Two trials involving 175 pigs of mixed breeding, averaging 5 weeks of age and 8.5 kg, were carried out to determine the efficacy of supplemental lysine and methionine when added to a low-protein starter diet. A basal corn-soybean meal diet containing 16% protein was supplemented with either lysine or a combination of lysine and methionine to bring the levels of these amino acids up to those contained in a 19% protein corn-soybean meal diet. A 19% protein complex starter diet containing corn, soybean meal, rolled oats, fishmeal and dried whey was also fed in these trials. In the first trial lysine addition increased rate and efficiency of gain. Addition of methionine to the lysine-supplemented diet was without effect. Weight gain of pigs fed the 16% protein, lysine-supplemented diet was equivalent to that of pigs fed the 19% protein corn-soybean meal control diet. In the second trial there were no differences in gain among treatments, but lysine addition increased gain/feed ratio. Methionine again was without effect. Pigs fed the 19% protein complex starter diet exhibited feed efficiencies superior to those of pigs fed the remaining diets.A third trial was conducted to determine the efficacy of rolled oats in a 19% protein complex starter diet. Crossbred weanling pigs were fed diets in which rolled oats contributed either none, ⅓, or ½ of the grain portion, the rest being comprised of ground yellow corn. Pigs performed similarly on all treatments, suggesting that rolled oats are of questionable value in diets for young pigs.

The influence of antibiotics in diets on antibody response to specific antigens has been measured in 144 early-weaned pigs. In the first experiment with pigs challenged at 27 days and antibody titer measured at 40 days the response was low and differences between treatments were not significant. In all remaining experiments in which pigs were 13 to 14 days older at time of challenge those pigs receiving zinc bacitracin, cycloserine and neomycin produced significantly greater antibody responses to bacterial antigens than did control pigs. Treatment differences occurred with antibiotics readily absorbed and with antibiotics minimally absorbed. The data suggest that the effect is initiated within the intestine. Weight gain was not significantly affected by treatment suggesting that antibody response differences occur previous to effects on weight gain.

Four trials involving 146 finishing pigs were conducted to determine the lysine requirement for maximum carcass lean cuts and for maximum protein and minimum fat in certain muscles. Graded levels of L-lysine HC1 were added to a 13.3% protein corn-sesame meal diet containing 3,501 kcal metabolizable energy per, kilogram. Levels of .35, .45, .55, .65 and .75% dietary lysine were studied in trials 1 through 3, while in trial 4 an .85% level was also included. Values for each criterion from the four trials were pooled and the lysine requirement was determined by the method of least squares. The estimated dietary requirement for percent four lean cuts was .51 ± .03% and for cross-sectional area of the longissimusmuscle it was .60 ± .05%. Estimated requirements for maximizing percent protein in the longissimus, semitendinosus,and latissimus dorsimuscles were, respectively, .52 ± .04, .47 ± .04, and .56 ± .04% of the diet. The corresponding requirements for minimizing percent ether extract in these muscles were .55 ± .03, .53 ± .03 and .49 ± .02% of the diet.

Four studies were conducted with the solid precipitate of aerobically sustained swine waste. Settled solids (ODR) collected from an oxidation ditch and containing 27.7% protein were substituted for other protein sources in studies with weanling rats. The protein of ODR could replace one-third to one-half of the protein of casein or soybean meal and support similar weight gains although gain/feed ratio decreased as ODR was increased in the diet. Feed intake was not reduced by the addition of ODR in any of the studies. The protein and energy digestibility values for ODR were less than those for the casein containing basal diet. The addition of lysine or tryptophan individually to a corn-ODR diet did not influence gain while the combination significantly increased gain and gain/feed suggesting that these amino acids were most limiting and nearly equally limiting in that diet.

CORN gluten feed contains on the average 22% (21 to 25%) crude protein, 2.0% (1.0 to 4.0%) ether extract and 9.0% (7.0 to 10.0) crude fiber (Cooley, 1970). And it has traditionally been classified as a protein supplement feed. Evvard (1920) reported that when corn gluten feed was mixed with tankage feed consumption and rate of gain of finishing swine were reduced. He attributed this adverse effect to the increase in crude fiber and reduced acceptability of the mixture by the pig.Several workers (Troelsen and Bell, 1962; Seerley, Miller and Hoefer, 1962; Laird and Robertson, 1963; Jensen and Becker, 1965; Hintz and Garrett, 1967; Chamberlain et al.,1967) have shown improved feed utilization as a result of pelleting diets or diet ingredients.The present study was conducted to study (1) the value of corn gluten feed (CGF) as a replacement for corn or for corn and soybean meal in diets for swine, (2) the effect of pelleting on utilization of CGF-containing diets by pigs and (3) the effect of pelleting of CGF on the availability of its tryptophan to pigs and rats.