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.

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.

Three experiments of 5 wk duration were conducted to evaluate the effect of reduced nocturnal temperatures (RNT) on weaned pig performance. Treatments were 1) a control regimen (CR) of 30 C constant air temperature lowered 2 C/wk and 2) a regimen where the temperature from 1900 to 0700 h was lowered to 25 C for three nights followed by 20 C for four nights during the first week and then lowered 1 C/wk thereafter (RNT

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 taUow (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 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<.O02), consumed less feed (P<.02) and converted feed more efficiently (P<.OO2) 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 trims 3 and 4 (P<.O02). Crude protein, Ca, P and Ca 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<.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 particle sizes of 14, 4, and 1.5 Wm (P<.O02) and .4/~m (P=.07). The amount of settled dust was lower (P<.O01, trials 1, 3 and 4) when tallow was included in the diet. There was no difference between the two dietary treatments in the incidence of abnormal turbinates in all four trials. There was a trend for pigs fed the diet without tallow to have more severe forms of lung lesions than those fed the diet with tallow in trials 1 and 3. The results of microscopic examination and crude protein analysis of settled dust indicated that the swine-house dust was mainly feed dust.

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.