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Few issues in swine production are as complex as floor space allowances. One method for pork producers to calculate floor space allowance (A) is to convert BW into a 2-dimensional concept yielding an expression of A = k * BW(0.667). Data on ADG, ADFI, and G:F were obtained from published peer-reviewed studies. Five data sets were created: A = grower-finisher pigs, fully slatted floors, and consistent group size; B = grower-finisher pigs and fully slatted floors (group size did not need to be consistent); C = grower-finisher pigs, partially slatted floors, and consistent group size; D = grower-finisher pigs, partially slatted floors (group size did not need to be consistent); and E = nursery pigs, fully slatted or woven wire floors (group size did not need to be consistent). Each data set was analyzed using a broken-line analysis and a linear regression. For the broken-line analyses, the critical k value, below which a decrease in ADG occurred, varied from 0.0317 to 0.0348. In all cases the effect of space allowance on ADG was significant (P < 0.05). Using the linear analyses based on data with k values of < 0.030, the critical k values for the 4 grower-finisher data sets did not differ from those obtained using the broken-line analysis (0.0358 vs. 0.0336, respectively; P > 0.10); however, none of the linear regressions explained a significant proportion of the variation in ADG. The slopes for the nonplateau portion of the broken-line analyses based on percent values varied among data sets. For every 0.001 decrease in k (approximately 3% of the critical k value), ADG decreased by 0.56 to 1.41%, with an average value of 0.98% for the 5%-based analyses. The use of an allometric approach to express space allowance and broken-line analysis to establish space requirements seem to be useful tools for pig production. The critical k value at which crowding becomes detrimental to the growth of the pig is similar in full- and partial-slat systems and in nursery and grower-finisher stages. The critical point for crowding determined in these analyses approximated current recommendations to ensure the welfare of pigs.

An experiment using 264 crossbred barrows was conducted to examine the interaction between space allocation and dietary ractopamine addition on pig performance and carcass characteristics using a 2 x 2 factorial arrangement of treatments. Treatments were 0.55 (19 pigs per pen) or 0.74 (14 pigs per pen) m2/pig from start (29.7 +/- 0.1 kg BW) to slaughter (108 kg BW) in a fully slatted facility and 0 or 10 ppm (as-fed basis) ractopamine for 28 d before slaughter. There were few treatment interactions. Pigs given 0.55 m2/pig had a lower ADG (P = 0.010), ADFI (P = 0.088), 10th-rib backfat depth on d 86 (P = 0.010), and carcass loin muscle depth (P = 0.011) than pigs given 0.74 m2/pig. There was no difference in feed conversion (P = 0.210) as a result of space allocation. Pigs fed diets containing 10 ppm ractopamine had decreased (P = 0.004) ADFI and improved (P = 0.001) feed conversion efficiencies for the 28-d feeding period, along with greater loin depth (P = 0.005) and carcass lean percent (P = 0.001). The improvements in 28-d carcass lean growth associated with feeding 10 ppm ractopamine resulted in an improvement in overall daily fat-free lean gain (P = 0.046). Under these experimental conditions, the response to dietary ractopamine was similar for crowded and uncrowded pigs.

One hundred ninety-six crossbred barrows of high lean gain potential (21.2 kg BW) were used in an experiment to determine the effect of dietary feather meal (FM) on barrow performance, specifically, the effects of the ingredient on ADG and carcass leanness. Additionally, 28 gilts (26.8 kg BW) were used to compare gender differences on the corn-soybean meal control diets. Treatments were control barrows and control gilts fed corn-soybean meal diets, and barrows fed according to a 2 x 3 factorial arrangement of FM levels (10 or 20%, as-fed basis) and starting weights on the diets (36, 60, or 86 kg BW). All barrow diets were formulated to contain the same apparent digestible lysine and ME. Control barrows ate more feed (2.61 vs. 2.39 kg/d; as-fed), grew faster (0.911 vs. 0.827 kg/d), had greater backfat depth at slaughter (15.6 vs. 11.6 mm), and had lower carcass lean content (P < 0.001), with no difference in daily lean gain (P = 0.848) compared with gilts. There was a linear (P = 0.010) decrease in ADG for barrows fed increasing amounts of FM from 36 kg BW to slaughter, with no effect of FM additions on ADG when initiated at 60 or 86 kg BW. There was a quadratic reduction (P = 0.008) in ADFI and estimated digestible lysine intake with increasing FM for the 36 to 60 kg BW period for barrows fed FM starting at 36 kg BW. There was a linear (P = 0.006) decrease in ADFI for the 60 to 86 kg BW period with increasing FM for barrows started on FM at 60 kg BW. There was no effect of experimental diets or starting weight on barrow 10th-rib backfat depth at slaughter. These results suggest that diets containing 10 and 20% FM were effective in decreasing overall ADG and ADFI by barrows when feeding of FM was initiated at 36 kg BW; however, backfat at slaughter was still greater than for control gilts.

Two experiments were conducted to determine the variation in response to space allocation between barrows and gilts and to examine an alternative allocation regimen for barrows and gilts. Experimental space allocations in both experiments were achieved by varying the number of pigs per pen in a fully slatted facility. In Exp. 1, barrows were given 0.58 and 0.65 m2/pig (nine and eight pigs per pen, respectively) and gilts were given 0.65 and 0.74 m2/pig (eight and seven pigs per pen, respectively). In addition, barrows at 0.58 m2/pig were fed diets formulated for barrows or diets formulated for gilts. Barrows grew 4.8% slower (P = 0.031) and ate 3.1% less feed daily (P = 0.062) at 0.58 vs. 0.65 m2/pig from 22 to 115 kg BW, with no difference in feed conversion, daily lean gain, carcass lean percent, or variation in weight within the pen at time of first pig removal to slaughter. There was no improvement in daily gain, feed intake, feed efficiency, lean gain, or carcass lean percent when gilts were given 0.74 vs. 0.65 m2/pig from 22 to 115 kg BW. There was no difference in performance between the population that consisted of barrows and gilts at 0.65 m2/pig vs. the population of barrows at 0.58 m2/pig and gilts at 0.74 m2/pig. There was no difference in performance by barrows at 0.58 m2/pig when fed either barrow or gilt diets, except for a slight increase (P = 0.078) in within-pen weight variation when the first pig was removed for slaughter for the barrows fed gilt diets. In Exp. 2, barrows and gilts were given 0.58 m2/pig or 0.74 m2/pig (18 vs. 14 pigs per pen) from weaning (mean age 17 d) to slaughter on d 168 postweaning. There were no interactions between space allocation and gender. Daily gain and feed intake were decreased by 2.8% (P = 0.037) and 2.9% (P = 0.084), respectively, with no effect on feed conversion or standardized fat-free lean daily gain for the 0.58 vs. the 0.74 m2/pig treatment, whereas total live weight gain per pen was increased 20.8% (P < 0.001). Results of Exp. 1 suggest that space allocation can be used to achieve similar growth rates between barrows and gilts, and results of Exp. 2 suggest that the response to space allocation is similar for barrows and gilts. The difference in magnitude of response to space allocation between experiments may be due in part to when the social group was formed, with a smaller difference in performance in Exp. 2 associated with a stable social group from weaning to slaughter.

Two experiments were conducted to determine the effect of lightweight pig removal and remixing on performance to slaughter. Experiment 1 was a growing-finishing trial utilizing a total of 900 pigs (26.2+/-0.1 kg initial weight) that were sorted and remixed at a mean replicate BW of 72 kg. Experiment 2 was a wean-to-finish trial (17 d mean wean age; 4.8 kg +/- 0.1 BW) utilizing 225 barrows with sorting and remixing occurring 3 wk after weaning. Treatments were 15 pigs/ pen from initial weight to slaughter (15S), 20 pigs/pen from initial weight to time of sort and remix and then reduced to 15 pigs/pen (20/15), and 15 pigs/pen from time of sort and remix to slaughter comprised of the five lightest pigs from each of three 20/15 pens per replicate (15M). Space allocation was 0.56 m2/pig from 26 to 70 kg and 0.74 m2/pig thereafter in Exp. 1. In Exp. 2, pen size was fixed at 2.44 x 4.27 m. In Exp. 1, there was no effect (P > 0.20) of treatment on performance prior to 70 kg. Least squares means for ADG from time of sort and remix to first pig removal from a pen for slaughter at 113 kg were 0.93, 0.87, and 0.91 kg/d for the 20/15, 15M, and 15S treatments, respectively (P < 0.05). When comparing the population represented by the 20/15 + 15M treatments vs the 15S population, there was no difference (P > 0.20) in ADG, ADFI, feed conversion, or carcass lean content. In Exp. 2, pigs in the 20/15 treatment grew slower (P < 0.05) than 15S pigs for the first 21 d (0.20 vs 0.22 kg/d, respectively) with a lower ADFI (P = 0.06) and no difference in feed conversion. When comparing the population represented by the 20/15 + 15M treatments vs the 15S population after sorting and remixing, there was no effect (P > 0.15) of experimental treatments on ADG, ADFI, feed conversion efficiency, carcass lean content, or daily lean gain. These results suggest that removal of lightweight pigs and remixing of the removed pigs into pens of similar-weight pigs is ineffective in improving the overall performance of a population of pigs during the postweaning period.

In each of three trials, 240 crossbred barrows weaned at 17 d of age (5.1 kg BW) were assigned to one of three experimental treatments based on light and heavy weight outcome groups. Experimental treatments were 1) wean-to-finish at 0.69 m2/pig and 15 pigs/pen; 2) wean-to-finish double-stocked at 0.35 m2/pig, 30 pigs per pen for 8 wk and then randomly split into two pens (either stayed in same pen or moved to new pen) for growth to slaughter at 0.69 m2/pig; and 3) nursery facility for 8 wk at 0.35 m2/pig and 15 pigs/pen followed by move to the same grow-finish facility housing wean-to-finish and double-stocked pigs and maintaining pen integrity. Beginning at 38 kg BW, diets were supplemented with either bacitracin methylenedisalicylate at 33 mg/kg to slaughter or tylosin at 44 mg/kg to 59 kg BW and 22 mg/kg thereafter. There were no trial x treatment interactions, even though there was considerable variation in health status among trials. At the end of the 56-d nursery period, wean-to-finish pigs weighed more than nursery (28.7 vs 27.7 kg; P = 0.071) and double-stocked pigs (28.7 vs 26.9 kg; P = 0.002), due to greater ADG (wean-to-finish vs nursery; P = 0.062; wean-to-finish vs double-stocked; P = 0.002) and greater ADFI (wean-to-finish vs nursery; P = 0.024; wean-to-finish vs double-stocked, P = 0.002). There was no effect of treatments (P > 0.1) on ADG, feed conversion, carcass lean percentage, or lean gain during the growing-finishing period. There was also no effect of treatment (P > 0.1) on ADG or ADFI from weaning to slaughter. There was no difference (P > 0.1) between bacitracin methylenedisalicylate and tylosin for ADG, feed conversion, carcass lean percentage, or daily lean gain. These data suggest that housing 5-kg weaned pigs in fully slatted growing-finishing facilities from weaning to slaughter was not detrimental to overall performance. In this experiment, dietary additions of bacitracin methylenedisalicylate or tylosin from 38 kg BW to slaughter weight resulted in similar growth performance.

Two experiments were conducted to evaluate the possible interaction of nursery space allocations and grow-finish space allocations in swine. In Exp. 1, crowding was achieved by varying the number of pigs per pen. During the nursery phase, decreasing the space allocation (0.16 m2/pig vs 0.25 m2/pig; 8 and 12 pens per treatment, respectively) by increasing the number of pigs per pen (18 vs 12) resulted in a decrease in daily feed intake (0.609 vs 0.683 kg/d; P < 0.001) and daily gain (0.364 vs 0.408 kg/d; P < 0.001). Pigs were mixed within nursery treatment groups and reassigned to grow-finish pens (6 pens per treatment) at the end of the 35-d nursery period providing either 0.56 m2/pig (14 pigs/pen) or 0.78 m2/pig (10 pigs/pen). Crowding during the grow-finish phase decreased daily feed intake (P < 0.003) and daily gain (P < 0.001). In Exp. 2, space allocations of 0.16 m2/pig vs 0.23 m2/pig during the nursery phase (24 pens per treatment) resulted in a decrease in daily feed intake (0.612 vs 0.654 kg/d; P < 0.005) and daily gain (0.403 vs 0.430 kg/d; P < 0.001). Pigs remained in the same (social) groups when moved to the grow-finish phase. Unlike Exp. 1, there was no effect of crowding during the grow-finish phase (0.60 m2/pig vs 0. 74 m2/pig) on daily feed intake or daily gain. The difference in results between experiments suggests that the response to crowding during the grow-finish phase may depend in part on whether pigs are mixed and sorted following movement from the nursery.

Three experiments were conducted to determine the main and interacting effects on growth performance of floor space allowance and dietary lysine and energy concentrations for growing-finishing pigs. In each experiment, space allocations of .56 or .78 m2/pig were achieved with 14 or 10 pigs per pen, respectively. In Exp. 1, diets investigated were National Research Council (NRC) recommended nutrient densities, NRC plus 5% added fat (F), NRC plus .15% added L-lysine. HCl (L), and NRC plus fat plus lysine (FL) in a 4 x 2 x 2 factorial arrangement of diets with space and season (winter vs summer). In Exp. 2 and 3, a 2 x 3 factorial treatment arrangement was used to investigate space and diet effects. Diets investigated contained 0, 2.5, or 5% added fat (choice white grease [Exp. 2]; tallow [Exp. 3]) with L-lysine.HCl added to maintain a constant lysine:ME ratio. In Exp.1, pigs given .56 m2/pig vs .78 m2/pig ate less feed (P < .001) and grew slower (P < .001) with no difference in gain:feed ratio or carcass lean percentage. Feed intake was decreased (P < .005) and gain:feed ratio increased (P < .001) for the FL vs L diet. In Exp. 2, pigs given .56 m2/pig vs .78 m2/pig grew slower (P < .001) with a poorer gain:feed ratio (P < .05) and a slower rate of lean gain (P < .05). In Exp. 3, pigs given .56 m2/pig vs .78 m2/pig grew slower (P < .05) with no difference in gain:feed ratio and a slower rate of lean gain (P < .005). There was a linear improvement in ADG (P < .01, Exp. 2; P = .011, Exp. 3) and gain:feed ratio (P < .001, Exp. 2 and 3) with increasing amounts of fat in the diet. The lack of space x diet interactions in these experiments suggests that the reduction in ADG associated with the reduction in ADFI for pigs given less space is independent of dietary lysine and energy concentrations.

Two experiments were conducted to examine the space requirements of barrows grown to 136 kg BW. In Exp. 1, barrows (initial BW 19.5 kg) were allowed .65, .84, or 1.02 m2/pig floor space in a fully slatted facility with 12 pigs/pen. In Exp. 2, conducted at three experiment stations in the north central region of the United States (Iowa, Indiana, Nebraska), barrows (initial BW 55.5 kg) were allowed .65, .93, or 1.20 m2/pig floor space in either partially or totally slatted facilities. In Exp. 1, there was a linear (P < .05) decrease in ADG for the first 29-d period with increasing space. Overall, ADG responded in a quadratic (P = .09) manner to increasing space allocation (.841, .855, and .824 kg/d for the .65, .84, and 1.02 m2 treatments, respectively) with a linear (P = .06) decrease in gain:feed ratio (.322, .318, and .312). Space allocation had no effect (P > .10) on ADFI, last rib fat depth, or rate of lean gain. In Exp. 2, ADG improved linearly (P = .08) with increasing space (.836, .857 and .865 kg/d for the .65, .93, and 1.20 m2 treatments, respectively), with a quadratic (P = .07) response in gain:feed ratio (.270, .265, and .268, respectively). There was no effect of space allocation on uniformity of gain within a pen as measured by coefficient of variation for pig weights within a pen at the time of first pig removal. The results of these experiments suggest that performance of barrows grown to 136 kg BW was maximized with .84 to 1.0 m2 of floor space per pig.

A three-trial experiment using 3- to 4-wk-old newly weaned pigs was conducted to evaluate the possible interaction between a 16-h reduced nocturnal temperature regimen (RNT16) and a lowered nursery diet lysine regimen on weaned pig and subsequent growing-finishing performance. Nursery temperature treatments were 1) a control temperature (CT) regimen of 30 degrees C constant air temperature lowered 2 C degree/wk and 2) a regimen beginning 1 wk after weaning in which the temperature from 1600 to 0800 was lowered 6 C degree from CT. Within each temperature treatment, all pigs were offered a diet containing 1.20% lysine for the 1st wk after weaning followed by 1.20 or 1.10% lysine to 10.5 kg and 1.00 or .90% lysine to 20 kg. There was no interaction of temperature regimen and diet on overall nursery performance. The RNT16 pigs had improved (P = .1) ADG (.351 vs .342 kg/d) with no difference (P > .1) in ADFI (.693 vs .680 kg/d) or G:F (.508 vs .506) compared with CT. Pigs fed the lower lysine sequence had poorer (P < .0001) ADG (.333 vs .360 kg/d) and G:F (.487 vs .527) than controls. There was also no effect (P > .1) of RNT16 vs CT on subsequent performance to slaughter weight for ADG (.770 vs .755 kg/d) or G:F (.309 vs .311). There was also no effect (P > .1) of a lowered nursery lysine sequence compared to control on growing-finishing ADG (.768 vs .757 kg/d) or G:F (.312 vs .309).(ABSTRACT TRUNCATED AT 250 WORDS)

Three experiments using 864 crossbred feeder pigs were conducted to determine the effects of fat sources and a feed flavor in 3-wk receiving diets and a reduced nocturnal temperature regimen on commingled feeder pig performance. In Exp. 1, there was no response to a feed flavor on overall ADG or ADFI. Commingled pigs offered receiving diets containing 5% blended vegetable oil (5B) or 5% tallow (5T) did not differ in overall ADG (.61, .63 vs .61 kg/d) and gain:feed (.315, .307, .310) compared with pigs offered corn-soy diets. In Exp. 2, pigs offered corn-soy receiving diets containing 0, 2, 4, or 6% (C2, 2B, 4B or 6B) of a blended vegetable oil had a cubic (P < .075) response for overall ADG (.67, .68, .66, and .69 kg/d) and linear (P < .075) response for gain:feed (.309, .307, .316, and .317). Four percent tallow (4T), compared with 4B and 4% soybean oil (4SO), improved (P < .1) overall ADFI (2.24 vs 2.10 + 2.14 kg/d) with no effect on overall ADG. In Exp. 3, 4B compared with 4T and 4% yellow grease (4YG) resulted in a slower (P < .01) overall ADG (.63 vs .68 + .65 kg/d) with no difference in ADFI or gain:feed. When pooled across Exp. 2 and 3, there was no effect of a reduced nocturnal temperature (RNT) regimen imposed beginning 1 wk after arrival vs a constant temperature control regimen on overall ADG (.65 vs .67 kg/d) and gain:feed (.303 vs .304). When pooled across Exp. 2 and 3, pigs fed 4T had a better (P < .0005) overall ADG than pigs fed 4B (.68 vs .65 kg/d). These results suggest a differential response on overall performance due to fat sources in commingled feeder pig diets. The results do not support the use of the feed flavor tested or RNT to stimulate performance.

Two experiments, each consisting of three trials and using 3- to 4-wk-old newly weaned pigs, were conducted to evaluate the effects of two reduced nocturnal temperature regimens on weaned pig and subsequent growing-finishing performance and nursery energy (propane and electricity) use. In Exp. 1, nursery treatments were 1) a control temperature (CT) regimen of 30 degrees C constant air temperature lowered 2C degrees/wk and 2) a regimen for pigs in pens with hovers (MRNT-H) in which the temperature from 1900 to 0700 beginning 1 wk after weaning was lowered 6 C degrees from the 0700 to 1900 temperature setting, which was 3C degrees lower than CT. The nursery temperature treatments in Exp. 2 were 1) CT and 2) a 10C degrees reduction in air temperature (MRNT10) from 1900 to 0700 from CT beginning 1 wk after weaning. In addition, within each temperature, diet sequences of 1.2% lysine for 3 wk followed by 1.0% lysine vs 1.15% lysine offered continuously were evaluated. In Exp. 1, there was no effect (P greater than .1) of temperature on feed intake but ADG decreased (P less than .001) in two of the three trials for MRNT-H vs CT and feed/gain worsened (P less than .05) in all trials. In Exp. 2, there was no difference between MRNT10 and CT for ADG and feed/gain. No interaction was observed between nursery diet and temperature regimen for weaned pig performance. There was no effect (P greater than .1) in either experiment of nursery temperature on subsequent growing-finishing performance. Overall energy savings comparing the MRNT-H and CT treatments were 68 MJ per weaned pig. Energy savings for Exp. 2 were 79 MJ per weaned pig. Application of cyclical temperatures in a controlled manner can result in energy savings of approximately $50 per pig weaned under the conditions of these experiments.

Three experiments were conducted to determine the effect of receiving diets containing alfalfa meal and certain feed additives on performance of comingled feeder pigs transported 900 to 1,100 km. In Exp. 1, the inclusion of 9.4% dehydrated alfalfa meal in receiving diets for 2 wk resulted in no difference (P greater than .1) in gain or feed conversion from purchase to market compared with pigs fed a basal corn-soybean meal (CS) diet or a diet containing 20% ground whole oats (O). In Exp. 2, pigs fed receiving diets containing 10% dehydrated alfalfa meal had no improvement (P greater than .1) in gain (.60 vs .61 kg/d) or conversion (3.25 vs 3.17) compared with CS-fed pigs. In Exp. 3, pigs fed a receiving diet for 2 wk containing 10% mid-bloom alfalfa ate more (P less than .002) feed daily for 2 wk (.82 vs .76 kg) and overall (P less than .04; 1.92 vs 1.85 kg) and had an improved (P less than .03) daily gain from purchase to market (.61 vs .59 kg) compared with CS-fed pigs. In Exp. 2, pigs fed diets containing 44 mg/kg tylosin (T) gained similar to pigs fed no additive (O) and slower (P less than .01) than pigs fed 110 mg/kg chlortetracycline (CTC; .59, .60 and .63 kg/d), with no significant differences in feed to gain conversion (3.12, 3.23 and 3.18).(ABSTRACT TRUNCATED AT 250 WORDS)

A four-trial experiment utilizing 3- to 4-wk-old newly weaned pigs was conducted to evaluate the effect of a modified reduced nocturnal (MRNT) nursery temperature regimen on weaned pig and subsequent grower-finisher performance. Nursery treatments were 1) a control temperature (CT) regimen of 30 degrees C constant air temperature lowered 2 degrees C/wk and 2) a regimen beginning 1 wk after weaning in which the temperature from 1900 to 0700 was lowered 6 degrees C from CT. Weaned pigs gained faster (P less than .01) in the MRNT treatment than in the CT treatment, with gains in Trials 1, 2, 3 and 4 being .39 vs .37, .28 vs .27, .38 vs .37 and .39 vs .36 kg/d, respectively. This improvement in gain was due to an increase (P less than .005) in feed intake for the same periods (.60 vs .58; .48 vs .42; .59 vs .58; .63 vs .58 kg/d). There was no difference in feed conversion (P greater than .1). There was no effect (P greater than .1) of MRNT vs CT on subsequent performance to slaughter weight for average daily gain (.69 vs .69 kg/d), average daily feed (2.22 vs 2.23 kg/d) or gain/feed (.31 vs .31). These results support the conclusions that weaned pigs eat more feed and gain faster with a reduced nocturnal temperature scheme and that there are no carry-over effects during the growing-finishing phase.

An experiment was conducted to determine the effects of 1) long-acting oxytetracycline injection at market arrival, 2) feed or water access at the auction market and 3) receiving diet management on commingled feeder pig performance. A total of 288 commingled feeder pigs transported over 1,000 km after market management treatments were used in two trials. Pigs given access to feed and water (FW) at the market weighed more (P less than .001) following marketing and transport than pigs given water only (W). Pigs given neither feed nor water (N) were intermediate in arrival weight (19.7, 18.7 and 18.9 kg). There was no effect (P greater than .1) of feed and water offering at the market on final weight (96.6, 95.9 and 96.6 kg), overall average daily gain (.70, .69 and .70 kg/d), overall gain/feed (.31, .31, .32) or percentage death loss (1.0, 2.1 and 4.2%). Injection of long-acting oxytetracycline upon arrival at auction market had no effect (P greater than .1) on pig weight following marketing and transport (19.0 vs 19.2 kg), final weight (96.1 vs 97.0 kg), percentage death loss (3.4 vs 1.4%) or percentage of pigs treated (3.4 vs 4.9%). Compared to providing ad libitum access to feed, restricting feed intake by floor feeding for the first 7 d post-arrival reduced (P less than .01) rate of gain for the first 9 d (-.04 vs. .08 kg/d), but overall there was no effect (P greater than .1) on daily gain (.70 vs .69 kg/d) or gain/feed (.31 vs .31).

One hundred twenty crossbred feeder pigs were used in 2 trials to determine the effects of food and water deprivation at the auction market and the effects of protein levels of receiving diet on blood chemical values. Food- and water-deprived animals had significantly higher packed-cell volume, colloid osmotic pressure, and cortisol values than did nondeprived animals. Total osmolality and plasma triiodothyronine values were significantly lower in deprived animals. Measurable effects of food and water deprivation were no longer apparent by 14 days after arrival at the research facility. Plasma colloid osmotic pressure had a positive linear relationship with increasing dietary protein level and was statistically different among levels of protein fed. Gilts had higher plasma triiodothyronine values than did barrows. Differential WBC ratios were not different between groups. Measurable differences for treatments (food and water deprivation vs food and water access; and level of protein in the receiving diet) were no longer apparent 84 days after pigs had arrived at the finishing unit.

Four trials were conducted with 1,480 pigs (initial wt: 23 kg in trial 1,29 kg in trial 2 and 49 kg in trial 3 and 4) to determine the effect of dietary fat on pig performance, nutrient separation in an automated feed distribution system, dust levels in swine buildings and integrity of the respiratory system of swine. Two modified-open-front (B-1 and B-2) and two environmentally regulated (E-1 and E-2) growing-finishing buildings, of identical design, were used in each trial. In trial 1, 250 pigs (25 pens of 10 pigs/pen) in B-1 were fed a ground, mixed, corn-soybean meal diet (15% crude protein) with added tallow (5%), and 250 pigs in B-2 were fed the same diet but without added tallow. The assignment of diets to buildings were reversed in trial 2 in which 2.5% tallow was used instead of 5%. Each diet was fed ad libitum to pigs, and was distributed by an automated "Flexauger" system in trials 1 and 2. In each of trials 3 and 4, 120 pigs (12 pens of 10 10 pigs/pen) in E-1 were fed a corn-soybean meal diet (14% crude protein) with added tallow (5%) and 120 pigs in E-2 were fed the same diet but without added tallow. Overall, pigs fed the diet with tallow gained faster (P less than .002), consumed less feed (P less than .02) and converted feed more efficiently (P less than .002) than those fed the diet without tallow in trials 1 and 2. Pig performance was also improved by the addition of tallow to the diet in trials 3 and 4 (P less than .002). Crude protein, Ca, P and Cu contents of both diets were similar at each location sampled throughout the automated distribution system in trials 1 and 2. Addition of tallow to the diets reduced aerial dust levels, both with the feed distribution auger running (P less than .002) and without the auger running (P = .06) in trials 1 and 2. In trials 3 and 4, adding 5% tallow to the diet reduced aerial dust concentrations of of particle sizes of 14, 4, and 1.5 micron (P less than .002) and .4 micron (P = .07). The amount of settled dust was lower (P less than .001, trials 1, 3 and 4) when tallow was included in the diet.(ABSTRACT TRUNCATED AT 400 WORDS)

In four trials, steer calves were received in the feedlot, processed and fed diets supplemented with soybean meal (SBM), 1% urea (UR) or 1% urea plus sarsaponin (S) over a 28-d period. In trials 1 and 2, the feeding period was extended to approximately 62 d, in which steers were fed a common (SBM) diet the last 34 d. In trials 3 and 4, a SBM plus S diet treatment was included. During the first 28 d (four trial summary) daily gains of steers fed urea plus S (.74 kg) were intermediate to and significantly different from gains of steers fed SBM (.84 kg) or UR (.66 kg) diets. However, at the end of the 62-d feeding period (two trial summary) daily gains, feed intakes and feed efficiency did not differ (P greater than .05) among treatments. No significant improvements in performance were found in steers fed SBM diets supplemented with S. In swine trials, pigs were fed diets containing no additive, 63 mg S X kg-1, 55 mg chlortetracycline (C) X kg-1 or S plus C in a grower-finisher (GF) and grower (G) trial. In the GF trial, overall efficiency of feed conversion was improved (P less than .05) by feeding S or S plus C. In the G trial, daily gains and intakes were greatest for pigs fed S plus C and differed (P less than .1) from those of pigs fed S or C in the diet. Compared with feeding S or C alone, gain and intake of growing pigs were stimulated to a greater extent when S was fed in combination with C. Feeding S with or without C improved efficiency of feed conversion in finishing pigs.

A total of 288 commingled crossbred feeder pigs were purchased and transported 1,050 km in two trials to investigate the effect of added dietary potassium chloride in receiving and finishing diets on feeder pig shrink recovery, performance and pre-slaughter shrink. Diets containing 0, .48%, .96% or 1.44% added potassium chloride were fed for 2 wk post-arrival and again from 12 wk post- arrival until slaughter. There was no effect (P greater than .1) on gain (22.9 kg pay weight) or feed conversion or on plasma or red blood cell potassium for the 2-wk post-arrival period due to the inclusion of potassium chloride in the 2-wk receiving diet. Also, there was no effect (P greater than .1) of potassium chloride in diets from 12 wk post-arrival until slaughter on gain, feed conversion, market shrink, carcass dressing percentage and plasma or red blood cell potassium concentration at slaughter. These results suggest that corn-soybean meal-based diets contain sufficient potassium for pigs following a period of stress associated with marketing and transport.

Two experiments were conducted to determine the effects of feed and water restriction and receiving diet crude protein level on feeder pig performance. In Exp. 1, a total of 239 commingled feeder pigs transported over 1,000 km were used in two trials. Pigs given access to feed and water (FW) at the market weighed more (P less than .0001) following marketing and transport than pigs given no feed and water (N) for the comparable 25-h market period (20.7 vs 19.6 kg). While FW pigs weighed less (P less than .02) than N pigs at the conclusion of the trials (93.9 vs 96.6 kg), there was no effect (P greater than .1) on overall average daily gain (.32 vs .35). There were no effects of receiving diets containing 12, 16 or 20% crude protein on daily gain, daily feed intake or feed efficiency for the overall growing-finishing period. Scour scores on d 8, 9, 10, 11, 13 and 14 post-arrival increased (P less than .01) with increased levels of protein in the receiving diets. In Exp. 2, a total of 360 crossbred feeder pigs was mixed and moved from a nursery to grower-finisher facilities in three trials, given feed and water access immediately (FWG) or denied access for 44 h (NG). At the end of the 44-h period, FWG pigs were heavier than NG pigs (P less than .0001; 18.3 vs 16.7 kg). There was no treatment effect on overall pig weight, daily gain or feed efficiency.