Effect of dietary electrolyte balance on nutrient digestibility determined at the end of the small intestine and over the total digestive tract in growing pigs

A replicated 4 x 4 Latin square digestion trial was conducted to determine the effect of electrolyte balance (EB = Na + K - Cl meq/kg of the diet) on apparent nutrient digestibilities in pigs fitted with ileal T-cannulas. Experimental diets were composed of corn and soybean meal with dietary EB altered by the substitution of CaCl2 for CaCO3, or NaHCO3 for corn and soybean meal. Electrolyte balance levels examined were -50, 100, 250 or 400 meq/kg of the diet. Increasing dietary EB concentration linearly increased (P less than .05 to P less than .02) apparent ileal digestibility of N, energy, DM and all amino acids, except alanine and methionine. However, nutrient and amino acid digestibilities measured over the total digestive tract were similar (P greater than .16) among EB levels. Increasing dietary EB resulted in a linear and quadratic (P less than .03) effect on daily urinary N excretion, resulting in a linear (P less than .05) improvement in N retention expressed both as a percentage of N intake and of absorbed N. Blood pH, total CO2, HCO3 and base excess concentrations increased linearly (P less than .02 to P less than .001) with increasing dietary EB. Dietary EB concentrations influenced nutrient and amino acid absorption measured near the end of the small intestine. Additionally, the N balance data per unit of N intake or N absorbed are indicative of an improved N utilization in pigs fed increasing dietary EB concentrations from -50 to 400 meq/kg.     

Dietary sodium and chloride levels for growing-finishing pigs

The performance and the physiological and metabolic consequences of three dietary levels of Na (.03, .09 and .18%) and of Cl (.08, .17 and .32%) arranged factorially were determined in growing-finishing pigs (36 to 89 kg). Average daily gain and feed efficiency of pigs fed .03% Na were lower than pigs fed .09 or .18% Na. Gain:feed ratio of pigs fed .32 or .17% Cl was greater than that of pigs fed .08% Cl during the finishing phase (58 to 89 kg) but not during the growing phase. Increasing dietary Cl levels increased average daily feed intake and gain:feed ratio of pigs fed .03% Na, but had no effect at the higher levels of Na. Plasma Na and Cl were lower (P less than .05) while plasma K (P less than .01), total protein, (P less than .04), albumin (P less than .07) and urea N (P less than .03) were higher in pigs fed .03% Na compared with those fed .09 or .18% Na. Increasing the dietary levels of Cl decreased urea N (P less than .05). Plasma lysine:arginine ratio increased as dietary Cl increased in pigs fed .18% Na diets, but not in pigs fed .03 or .09% Na. The urea cycle intermediate ornithine was highest in the plasma of pigs fed .18% Na. Dietary Na and Cl seem to interact to affect both plasma electrolytes and basic amino acid metabolism.     

Effect of feather meal on live animal performance and carcass quality and composition of growing-finishing swine

A total of 252 crossbred pigs were used in two experiments to determine the effect of feeding hydrolyzed feather meal (FM) during the growing-finishing period on animal performance, carcass composition, and pork quality. All pigs were blocked by weight, and dietary treatments were assigned randomly to pens within blocks. In Exp. 1, 24 pens were randomly assigned to one of three dietary treatments: 1) control corn-soybean meal starter, grower, and finisher diets devoid of FM; 2) control diets formulated with 3% FM; and 3) control diets formulated with 6% FM. During the starter phase, there was a quadratic decrease in average daily gain (P < 0.06) and gain:feed (P < 0.01) with increasing FM, and during the grower-II phase, gain:feed increased linearly (P < 0.07) with increasing FM inclusion level. However, dietary FM had no effects (P > 0.10) on performance during the grower-I phase, finisher phase, or in the overall trial. Moreover, carcasses from pigs fed 3% FM had greater (P < 0.05) average backfat depth than carcasses of pigs fed 0 and 6% FM, but FM did not affect (P > 0.10) ham or carcass lean composition. In Exp. 2, 24 pens were randomly allotted to one of four dietary treatments: 1) positive control corn-soybean meal-based starter, grower, and finisher diets; 2) negative control corn-soybean meal- and wheat middlings-based starter, grower, and finisher diets; 3) negative control diets formulated with 3% FM; and 4) negative control diets formulated with 6% FM. Dietary FM had no effect (P > 0.10) on average daily gain, average daily feed intake, or gain:feed during any phase of the experiment. Ham weight decreased linearly (P < 0.04), whereas ham lean weight increased linearly (P < 0.09), with increasing levels of FM in the diet. Pork from pigs fed 3% FM tended (quadratic effect, P < 0.10) to receive higher Japanese color scores than pork from pigs fed either negative control or 6% FM diets. Moreover, pork color became lighter (P c 0.08), less red (P < 0.001), and less yellow (P < 0.003) as FM level was increased in swine diets. Results from these two experiments indicate that as much as 6% FM can be incorporated into isolysinic diets of growing-finishing pigs without adversely impacting animal performance, carcass composition, or pork quality.     

Effect of dietary electrolyte balance on growth and acid-base status in swine

The effect of dietary electrolyte balance on pigs fed lysine- or tryptophan-adequate or tryptophan-deficient diets was investigated in four experiments using 8- to 12-wk-old pigs. Electrolyte balance, expressed as Na+K-Cl in meq/kg of diet, was varied by altering dietary levels of Na and Cl while holding all other minerals constant. In two experiments in which the basal diet contained a balance of 135 meq/kg, simple lysine or tryptophan deficiences caused depressed growth, feed intake and efficiency of feed utilization, but none of these responses was altered by dietary supplementation with NaHCO3. In one experiment in which the electrolyte balance of the basal diet was 61 meq/kg and in which both lysine and tryptophan were limiting. NaHCO3 supplementation significantly increased growth and feed intake. This did not occur if the diet was also supplemented with tryptophan. A final experiment was conducted to determine the response of pigs to a range of electrolyte balance (-85 to 341 meq/kg) in a practical corn-soy diet containing adequate levels of all amino acids. Growth and feed intake appeared to be maximal for balances of 0 to 341 meq/kg Na+K-Cl, but were decreased at -85 meq/kg (P less than .05). Acid-base balance was adversely affected at 0 meq/kg. The results suggest that the response of lysine-deficient pigs to sodium bicarbonate is dependent upon the electrolyte balance of the diet, and also is influenced by other dietary amino acids.     

Effect of dietary calcium and phosphorus level sequences on performance, structural soundness and bone characteristics of growing-finishing swine

The effects of feeding various dietary Ca:P level sequences on gain and feed efficiency, leg structural soundness and bone indices of growing-finishing swine were evaluated as an incomplete 3 X 3 factorial arrangement of treatments in a split-plot design. A total of 664 pigs were fed one of three total dietary Ca:P levels (.52:.40, .65:.50, .80:.60%) from 19-kg to 56-kg body weights followed by one of three Ca:P levels (.45:.32, .52:.40, .65:.50%) to market weight. The .80:.60% and .65:.50% Ca:P mineral sequence was not evaluated. Diets were formulated to 14.5% crude protein using a corn-soybean meal mixture with proportions of dicalcium phosphate and limestone altered to attain the desired dietary Ca:P levels. Maximum gains occurred at the .65:.50% and .52:.40% Ca:P level during the grower (P less than .01) and finisher (P less than .01) periods, respectively. No grower X finisher phase pig gain or feed intake interaction resulted, providing evidence of no carry-over response on these measurements from the grower to the finisher period. Serum P concentration increased and plateaued at the same dietary Ca:P level, as did rate of gain at both 56-kg and 95-kg body weights. Leg soundness subjectively evaluated at 56-kg and 95-kg body weights revealed no effect of dietary Ca:P level on soundness scores at 56 kg, but at 95-kg body weight, the interaction between grower and finisher diets was significant. Percentage bone ash of the humerus, shaft thickness and bending moment of the femur increased as dietary Ca:P level increased at both 56-kg and 95-kg body weights.(ABSTRACT TRUNCATED AT 250 WORDS)     

Supplementing salinomycin to diets for growing-finishing pigs

Feeding experiments with growing-finishing pigs were carried out to study the effect of different dietary salinomycin concentrations upon animal performance. Besides a dietary treatment without antibiotic, three treatments consisted of 20/10 mg/kg, 40/20 mg/kg and 60/30 mg/kg salinomycin (the first and second number refer to the salinomycin content in grower and finisher diet, respectively). Compared to the control group, feeding diets with 20 or 40 mg/kg salinomycin resulted in significantly higher weight gain in the grower period (25-45 kg body weight), while also feed conversion was lower (although not statistically significant). In the finisher period (45-100 kg body weight) salinomycin had no significant effect upon weight gain or feed conversion efficiency, but the 20 and 30 mg/kg treatments yielded the best results. Considering the grower and finisher period together the dietary treatments 40/20 mg/kg and 60/30 mg/kg showed highest growth rate and most favourable feed conversion, although not statistically significant. Carcass characteristics (dressing percentage, carcass length, backfat thickness, percent meat) were not affected by dietary salinomycin supplementation.     

Interactive effects of dietary calcium, phosphorus and copper on performance and liver stores of pigs

Three experiments involving 304 pigs were conducted to determine the related effects of copper (Cu), calcium (Ca) and phosphorus (P) on the performance and liver Cu stores of growing-finishing pigs. Rate and efficiency of gain were improved by the addition of 250 ppm of Cu to the diets. Improvements in rate of gain averaged 6.6% (652 vs 696 g/d) to 60.5 kg body weight and 1.7% (713 vs 725 g/d) to 94.5 kg body weight. Feed:gain ratio was improved by 1.4% to 60.5 kg and 1.6% to 94.5 kg body weight when Cu was added to the diet. Increasing the dietary Ca and P levels from .65% Ca and .55% P to 1.2% Ca and .86 or 1.0% P resulted in increased (P less than .01) growth rate to 60 and 95 kg (649 vs 699 g/d and 700 vs 737 g/d, respectively), but feed efficiency was not affected (2.86 vs 2.84 and 3.18 vs 3.17 kg feed/kg gain, respectively.) Feeding the higher Ca and P levels resulted in increased liver Cu levels in pigs fed 250 ppm Cu (189 vs 323 ppm), but Ca and P did not affect liver Cu of pigs fed low Cu diets (29 vs 28 ppm). When dietary Ca and P were varied independently, the high Ca level increased liver Cu, but P had little effect on liver Cu. Increasing the dietary P level partially alleviated the effect of Ca on liver Cu.     

Requirement of true ileal digestible threonine of growing and finishing pigs

Ninety-six crossbred barrows and gilts were used to investigate the optimum supply of true ileal digestible threonine for growing (approximately 35-65 kg body weight) and finishing (approximately 65-110 kg body weight) pigs. For this purpose, according to a bifactorial arrangement in the grower as well as in the finisher phase four dietary threonine levels were combined with two dietary levels of lysine. Measurement criteria were body weight gain, feed intake, feed conversion rate and carcass characteristics. In the grower stage at the lower lysine level daily gain increased numerically (p < 0.1) and the feed to gain ratio decreased significantly with an increasing dietary true ileal digestible threonine concentration. Increasing the true ileal digestible lysine concentration of the diet from 7.8 to 9.2 g/kg increased average daily gain in the grower stage significantly from 815 to 855 g and decreased the feed to gain ratio significantly. In finishing pigs, daily gain and feed to gain ratio were significantly improved by an increasing dietary true ileal digestible threonine concentration from 821 to 902 g and from 3.14 to 2.94 kg/kg, respectively, but not by the differing lysine supply. As in the grower stage, barrows consumed more feed than gilts at similar growth rates and this resulted in a significantly reduced feed to gain ratio in gilts compared with barrows. The requirements of true ileal digestible threonine for optimize both, daily gain and feed to gain ratio, as derived by the broken-line model were 10.3 g/animal and day for growing and 10.7 g/animal and day for finishing pigs respectively.     

Effect of magnesium mica on performance and carcass quality of growing-finishing swine

A total of 240 crossbred pigs were used in two experiments to determine the effect of feeding magnesium mica (MM) during the growing-finishing period on animal performance and pork carcass characteristics. All pigs were blocked by weight, and treatments were assigned randomly to pens (five pigs/pen) within blocks. In each experiment, eight pens were allotted randomly to one of three treatments: 1) a negative control corn-soybean meal starter, grower, and finisher diet devoid of supplemental magnesium; 2) the control diets supplemented with 1.25% MM; and 3) the control diets supplemented with 2.50% MM. In Exp. 1, pigs were slaughtered at the University of Arkansas Red Meat Abattoir, whereas pigs in Exp. 2 were transported to a commercial pork packing plant and slaughtered according to industry-accepted procedures. In both experiments, dietary supplementation of MM had no (P > .10) effect on ADG, ADFI, or gain:feed ratio at any phase during the growing-finishing period. In Exp. 1, MM supplementation had no (P > .10) effect on carcass fatness or muscling. Moreover, Japanese color scores were not (P > .10) affected by feeding pigs MM; however, American color scores increased linearly (P < .01) with increasing levels of MM in the diet. Although MM supplementation did not (P > .10) affect L* and b* values for the longissimus muscle (LM), there was a linear increase (P < .05) in LM a* and chroma values associated with increased MM levels in swine diets. In Exp. 2, carcasses from pigs fed 1.25% MM had less (P < .05) fat opposite the LM at the 10th rib than untreated controls and pigs fed 2.50% MM and higher (P < .10) percentages of muscle than carcasses of untreated controls. Moreover, the LM from pigs fed 1.25% MM was less (P < .05) red and less (P < .05) yellow than the LM from pigs fed the control or 2.50% MM-supplemented diets. Drip loss from the LM was unaffected (P > .10) by inclusion of MM in the diet. Results from this study confirm that inclusion of MM, an inexpensive, inorganic magnesium source, in diets of growing-finishing swine has beneficial effects on pork carcass cutability and quality with no deleterious effects on live animal performance.     

Effect of dietary phosphorus concentration and electrolyte balance on the growth performance of broiler chickens

The performance of 1680 male and female broiler chickens given diets with either a low (4.7-4.3 g/kg) or high (8.9-8.2 g/kg) content of inorganic phosphorus and four (150, 200, 250 and 300 mEq/kg) electrolyte balances (Na+K-Cl) was measured from 1-d-old to 49 d of age. Diets with the higher concentration of inorganic phosphorus reduced body weight gains in the starter (P less than 0.01) and finisher (P less than 0.05) phases but the efficiency of food utilisation was reduced only in the starter phase (P less than 0.05). The reduction in body weight gain was greater in males than in females. The growth depression caused by the higher concentration of inorganic phosphorus in the finisher diets was partially alleviated by increasing the electrolyte balance to either 250 or 300 mEq/kg diet. The higher concentration of inorganic phosphorus significantly reduced the dressing percentage and increased the abdominal fat pad weight and litter moisture content. Electrolyte balance had no significant effects on efficiency of food utilisation, abdominal fat pad weights or litter moisture content. Neither the dietary concentration of phosphorus nor the electrolyte balance had a significant effect on mortality or ash content of the tibia.     

Duration of feeding conjugated linoleic acid influences growth performance, carcass traits, and meat quality of finishing barrows

Conjugated linoleic acid (CLA) was fed to growing-finishing barrows (n = 92) at 0.75% of the diet. A commercial CLA preparation (CLA 60) containing 60% CLA isomers was included at 1.25% to provide 0.75% CLA in the diet. The inclusion of CLA in diets was initiated at various BW and fed until slaughter. Growth, carcass, meat quality, physical, chemical, and sensory data were collected and analyzed. Treatments T1, T2, T3, and T4 included the last 0, 29, 56 and 87 kg, respectively, of weight gain before slaughter. Average daily gain and feed intake were not affected (P > or = 0.06) by CLA, but gain:feed responded quadratically (P = 0.05), over the entire BW gain (28 to 115 kg) with pigs of T2 and T3 having the greatest gain:feed. Loin muscle area increased (P = 0.01) linearly with increasing weight gain while fed CLA, and 10th rib, first rib, and last rib fat depth decreased (P < or = 0.05) linearly. Subjective quality measures on loin muscles increased linearly for marbling (P < 0.05) and tended to increase for firmness (P = 0.07) with increasing weight gain while barrows were fed CLA. Objective Hunter color values for loin chops from T1 and T4 were not different for L* (P = 0.12) or a* (P = 0.08) values but were higher (P < 0.05) for b* values with CLA feeding. Lipid oxidation values of loin muscle tissue were lower (P < 0.05) for pigs fed CLA (T1 vs T4). Increasing the period of weight gain while feeding CLA linearly increased (P < 0.01) saturated fatty acids and CLA isomers in loin tissue and linearly increased (P < 0.01) saturated fatty acids and CLA isomers in subcutaneous adipose tissue. Sensory panel characteristics of loin chops were not changed (P > 0.05) by feeding CLA. Increased gain:feed, increased loin muscle area, decreased fat depth, and improvements in marbling and firmness with CLA feeding could result in improved profitability of pork production systems.     

Response of starter pigs to supplementation of corn-soybean meal diets with organic acids

Four growth experiments were conducted to assess the effects of organic acid supplementation on performance of starter and finisher pigs. Three 4-wk starter experiments utilized 392 pigs fed simple corn-soybean meal diets. A fourth experiment employed 135 finisher pigs in a 6-wk study. Each of the starter experiments was initiated immediately after weaning; piglets were 30 +/- 3 d of age. In Exp. 1, weanling pigs fed a 19% crude protein, simple corn-soybean meal diet were compared with pigs fed similar diets supplemented with 2% propionic, fumaric, or citric acid. Addition of each acid improved (P less than .07) efficiency of gain, while propionate depressed (P less than .05) feed intake. Additions of 1, 2, 3 or 4% fumarate were made in Exp. 2, resulting in linear daily gain and feed efficiency improvements (P less than .05). In Exp. 3, a possible protein-sparing effect of fumaric acid was investigated. Increasing protein levels from 16 to 20% improved daily gain (P less than .01) and feed efficiency (P less than .0001); fumarate supplementation (2%) increased (P less than .01) gain:feed. However, there was no protein X fumaric acid interaction. In Exp. 4, no treatment effects were noted with performance of finisher pigs fed a 14% crude protein, corn-soybean meal diet was compared with that of pigs fed similar diets supplemented with 1.5 or 3% fumaric acid.     

Beef cattle feed intake and growth: empirical Bayes derivation of the Kalman filter applied to a nonlinear dynamic model

Feed intake and growth rate of a single group of growing-finishing feedlot beef cattle are difficult to predict. Subsequent performance can be projected more precisely from past performance of a group of cattle. Using an adaptation of the statistical procedure called the empirical Bayes (EB) derivation of the Kalman filter, estimates from any dynamic model (M) can be adjusted based on past performance. The model may be either linear or nonlinear. With this procedure, predictions of intake and body weight gain are periodically updated by multiplying the estimates from M by statistically weighted factors. These factors are derived from the ratio of performance in each period to the performance predicted by M. For comparison to the EB adjustment, weighting of factors by least-squares (LS) adjustment also was tested to predict subsequent feed intake and gain. The test data base consisted of periodic feed intake and gain observations (usually 28 d) for 200 pens of feedlot steers. Bias of prediction was lower for EB than for M or LS for feed intake and (usually) gain. Intake and gain prediction errors averaged for the whole feeding period were .42 kg/d for intake and .14 kg/d for gain by EB, being .84 and .18 kg/d more precise than M and .12 and .33 kg/d more precise than LS predictions. More than two observations were needed before LS produced accurate prediction but after about 80 d, LS and EB estimates converged. Accuracy of both estimates continued to improve as days on feed increased.(ABSTRACT TRUNCATED AT 250 WORDS)     

Growth performance and carcass traits of pigs subjected to marginal dietary restrictions during the grower phase.

Sixty-four individually housed pigs were used to investigate the effect of amino acid content of finisher diets on growth performance of pigs subjected to marginal dietary amino acid restrictions (80% of the 1988 NRC lysine recommendation) during the grower phase. In each of the two trials, low- and high-amino-acid grower diets (.421 and .765 g lysine/MJ DE, respectively) and four finisher diets (.421, .516, .612, and .707 g lysine/MJ DE) were randomly assigned within sex to 16 gilts and 16 castrated males weighing 23.0 +/- 2.0 kg in a 2 x 4 factorial arrangement of treatments. The average weight of pigs after a completion of diet change was 50.4 +/- 2.1 kg. All pigs were slaughtered at an average weight of 105.2 +/- 4.1 kg. Ultrasound backfat thickness was measured at the time of diet change and before slaughter. Pigs were allowed ad libitum access to feed and water. During the grower phase, pigs fed the high-amino-acid diet grew faster (P < .001) and more efficiently (P < .001) and had less ultrasound backfat (P < .001) than those fed the low-amino-acid diet. The grower diet had no effect on weight gain during the finisher phase. Consequently, pigs fed the high-amino-acid grower diet had better overall weight gain (P < .01) than those fed the low-amino-acid diet. The rate of lean accretion was, however, similar between the two groups of pigs. Furthermore, pigs fed the low-amino-acid grower diet seemed to have better carcass quality, as indicated by less ultrasound backfat (P < .01) and larger carcass longissimus muscle area (P < .05). Average and 10th rib carcass backfat decreased linearly (P < or = .05) and lean accretion rate improved linearly (P < .05) as the amino acid content of finisher diets increased, but there was no grower x finisher diet interaction in these and other response criteria. Although no evidence of compensatory weight gain was observed, it is possible that compensatory lean tissue growth may have occurred in pigs subjected to early amino acid restrictions at the expense of fatty tissue growth.     

Effect of vitamin E and copper on the vitamin E status and performance of growing pigs

A 13-wk trial was conducted with 32 pigs to determine the effects of dietary Cu (250 ppm) and alpha-tocopheryl acetate (ATA, 22 IU/kg) on the performance, serum enzymes, serum and tissue tocopherols, and antibody production in growing pigs. Pigs were fed corn-soybean meal diets containing 21% CP the first 4 wk and 18% CP during the rest of the trial. All feed was stored a minimum of 14 d before it was fed. The addition of Cu decreased (P less than .01) the concentration of alpha-tocopherol in the feed. alpha-Tocopherol concentrations were less than .01 mg/kg in the starter diet and less than 2 mg/kg in the grower diet after 14 d of storage. Supplemental Cu or ATA had no effect on ADG, feed intake, or gain:feed during the first 4 wk. During wk 5 to 13, the addition of Cu to diets containing no ATA increased daily feed intake and decreased gain:feed, but with ATA addition, feed intake decreased and gain:feed increased, resulting in a Cu x ATA interaction (P less than .05). The addition of Cu or ATA had no effect (P greater than .1) on serum glutathione peroxidase or lactic dehydrogenase activity. Serum tocopherols were reduced (P less than .05) by the addition of Cu during wk 1 to 4, 6 (P less than .01), and 7 (P less than .05) and increased (P less than .01) by ATA addition during the entire experiment. The addition of ATA increased the tocopherol concentrations in bile, ham, heart, pancreas, kidney, spleen, liver, psoas and longissimus muscle (P less than .01), kidney fat, backfat, and adrenal gland (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Dietary energy levels for growing-finishing pigs fed ad libitum. 2. Carcass effects and economic model of the responses

The NRC (1988) recommendations on nutrient standards for growing-finishing pigs assume a corn-based feeding regime. However, the diets used in Western Canada are generally barley-based and consequently are usually lower in digestible energy (DE) and result in reduced growth rate and feed efficiency. Corn and wheat can be included in the diet to raise the DE level, but since this could affect the carcass quality of pigs fed ad libitum, the influence of DE level in relation to carcass quality was measured in two experiments. An economic assessment of the data was also conducted. A total of 432 pigs was used, over the 20-98 kg live weight range. The inclusion of wheat or corn to barley-based diets during the finisher period resulted in reduced carcass quality, and there was also some evidence that increased dietary energy during the grower stage had the same effect.     

Influence of lasalocid and monensin plus tylosin on comparative feeding value of steam-flaked versus dry-rolled corn in diets for feedlot cattle

Two trials were conducted to characterize the differences in utilization of dry-rolled and steam-flaked corn in a growing-finishing diet for feedlot cattle supplemented with and without ionophores. Ionophore treatments were: 1) no ionophore, 2) 33 mg/kg monensin sodium plus 11 mg/kg tylosin and 3) 33 mg/kg lasalocid sodium. In trial 1, treatment effects on feedlot performance were evaluated in a 239-d growing-finishing trial involving 180 crossbred steers (approximately 25% Brahman with the remainder represented by Hereford, Angus, Shorthorn and Charolais breeds in various proportions) with an average initial weight of 153 kg. In trial 2, treatment effects on characteristics of digestion were evaluated using six steers of similar breeding and background to those used in trial 1, with cannulas in the rumen and proximal duodenum. There were no interactions between corn processing and ionophore supplementation (P greater than .20). Average daily gain was not affected by steam-flaking as opposed to dry-rolling, however, feed intake was decreased 5.4% and feed conversion was improved 6.8% (P less than .01). Steam-flaking increased the estimated net energy value of the diet 7.7% and 8.5% for maintenance and gain, respectively (P less than .01). Steam-flaking increased the digestibility of starch 6.6% (P less than .01). Steam-flaking increased ruminal molar concentrations of propionate and decreased acetate:propionate ratio and estimated methane production (P less than .10). Both monensin-tylosin and lasalocid resulted in reduced feed intake (12.3 and 6.5%, respectively, P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)     

冬季可拆迁式猪舍对生长育肥猪生长性能及舍内温湿度的影响

试验通过可拆迁式猪舍与传统(固定)猪舍的饲养对比试验,研究了冬季可拆迁式猪舍对生长肥育猪的生长性能及舍内温度和相对湿度的影响。选取同期转群、体重30 kg左右杜大长生长猪216头,随机分成可拆迁式猪舍组和传统猪舍组,每组3个重复,每个重复36头。试验至猪体重达到100 kg左右出栏结束。结果表明:可拆迁式猪舍组试猪的平均日增重和平均日采食量分别比传统猪舍组提高17.28%(P0.01)和12.13%(P0.01),饲料料增重比降低7.00%(P0.05);可拆迁式猪舍的舍内平均温度为20.33℃,比固定猪舍的16.86℃高3.47℃,比室外的15.15℃高5.18℃,差异均极显著(P0.01)。试验结果表明,可拆迁式猪舍对生长育肥的生长性能和室内环境控制优于传统猪舍。     

Recombinant porcine somatotropin alters performance and carcass characteristics of heavyweight swine and swine fed alternative feedstuffs

The efficacy of recombinantly derived porcine somatotropin (rpST) in improving the performance and carcass characteristics of heavyweight finishing pigs was determined. In Study 1, 36 pigs were killed for determination of initial carcass composition at 102 kg, and 36 pigs each were given 0, 1.5, 3, 6, or 9 mg of rpST/d from 102 to 136 kg live weight. Corn-soybean meal diets fed contained 19.8% CP and greater than 1% lysine. Study 2 tested the effects of 3 mg/d on pigs for 4 wk from 84 kg BW fed a corn-soybean meal or a triticale-barley-peas diet. Performance variables (ADG, average daily feed intake [ADFI], and feed efficiency [FE]) were measured weekly. Treatment with rpST increased (P less than .01) ADG and FE and decreased (P less than .01) ADFI in both studies. In Study 1, leaf fat, backfat thickness, belly thickness, and carcass fat were all decreased (P less than .01) linearly by rpST. Loin eye area (LEA), total trimmed lean, and total protein content were increased quadratically (P less than .01). At the 3-mg dose, ADFI, ADG, and FE were 87, 130, and 137% of control, and LEA, backfat, total protein gain, and total fat gain were 107, 80, 136, and 52% of control. Loin eye area was not increased (P greater than .05) in the pigs in Study 2; however, backfat thickness was reduced 16% by rpST (P less than .01). The effects of rpST were the same on both dietary regimens (P greater than .05). These studies demonstrate the effectiveness of rpST in increasing ADG and carcass leanness and improving FE in heavyweight pigs and in pigs fed alternative feedstuffs.     

Effect of biotin and(or) lysine additions to corn-soybean meal diets on the performance and nutrient balance of growing pigs

Supplementation of a basal corn-soybean meal diet with 0 or .2% L-lysine and 0, .25 or .55 ppm biotin produced six dietary treatments in a factorial arrangement. Pig performance, post-weaning scour scores, plasma urea N (PUN) levels, N and energy balance and liver pyruvate carboxylase activity (PC) were response criteria. Crossbred pigs were fed from weaning at 4 wk of age (8.0 kg) to market weight in performance trials utilizing 552 pigs in the 35-d starter period and 384 pigs in the subsequent grower (about 21 to 50 kg) and finisher (about 50 to 95 kg) periods. Pigs remained on their respective dietary treatments for the entire experiment. Energy and N balance trials were conducted utilizing 36 barrows from the grower period (avg 44.7 kg) and 36 barrows from the finisher period (avg 90.3 kg) of the performance study. Barrows were sacrificed following completion of the 6-d collection periods to measure liver PC activity. The basal starter diet contained 17.0% crude protein (CP), 86% lysine and .22 ppm biotin. Increasing the corn:soybean meal ratio reduced the dietary levels of CP, lysine and biotin to 14.8%, .69% and .19 ppm for the basal grower diet and to 11.1%, .50% and .17 ppm, respectively, for the basal finisher diet. Lysine supplementation improved (P less than .05) average daily feed intake and average daily gain for all periods, gain:feed ratios for the starter and grower periods and reduced (P less than .01) PUN levels at the end of the starter and finisher periods.(ABSTRACT TRUNCATED AT 250 WORDS)