Reduction of pig agonistic behavior by androstenone

One hundred twenty-four prepuberal crossbred pigs were used in a series of behavioral bioassays to determine the minimum dose of androstenone (5 alpha-androst-16-en-3-one) that would reduce the level of agonistic behavior among dyads of newly regrouped pigs. Randomly selected females and castrated males were used in 21-h videotaped observation periods. In Exp. 1, isopropyl alcohol was tested against no aerosol to determine if the vehicle (isopropyl alcohol) influenced agonistic behavior. Level of submissive and aggressive behaviors were similar (P greater than .10) between treatments. In Exp. 2, vehicle or androstenone in vehicle was sprayed on the snout and head of both pigs at the start of the encounter. Four bioassays were performed with four levels (.05, .5, 5 and 50 micrograms/pig) of androstenone dissolved in isopropyl alcohol. Sprayed isopropyl alcohol served as a control. At concentrations of .5 and 5 micrograms/pig, androstenone reduced aggressive behavior (P less than .05). Androstenone had no consistent effect on submissive behavior. In Exp. 3, androstenone was sprayed on pigs at the start of the encounter and again at 30, 60 and 90 min after pairs of pigs were mixed. Repeated application of this androgen resulted in levels of agonistic behavior similar to those recorded when nothing was applied (P greater than .10). A single application of as little as .5 micrograms androstenone per pig reduced aggressive behavior among prepuberal pigs and, therefore, may be a way of reducing fighting among newly regrouped prepuberal pigs.     

Effects of heat and social stressors and within-pen weight variation on young pig performance and agonistic behavior

A total of 486 crossbred weanling pigs was used in a series of experiments to determine first the effects of heat and social stress and their interaction on pig performance and, second, to determine a possible cause for the observed effects. Pigs were held six/nursery pen and fed and watered ad libitum. In Exp. 1, pigs were held at either thermal neutral 26.6 C for the 21 d and 23.8 C for the final 7 d, or at the heat-stress temperature (32.2 C) for the entire 28-d period. Within each temperature treatment, one-half of the pigs were left as single-litter controls and one-half were randomly regrouped (social stress). Pig feed intake and weight gain were reduced (P less than .05) among heat-stress pigs during the 7- to 28-d and 0- to 28-d periods. The interaction between social and thermal stress was significant for gain:feed ratio for the 7- to 28- and 0- to 28-d periods. Regrouping depressed gain:feed ratio only among heat-stressed pigs. In Exp. 2, a two-pig behavioral bioassay was used to determine if agonistic behaviors were influenced by heat stress. Pigs that were regrouped into 32.2 C rooms exhibited reduced mean level (P less than .05) and variation (P less than .001) of submissive behavior. Duration of aggressive behavior and latency to attack were unaffected by thermal treatments. Increased social stress at the time of regrouping could not account for poor performance of heat-stressed, regrouped pigs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Response of growing-finishing pigs to decreasing floor space allowance and(or) virginiamycin in diet

Five hundred forty crossbred pigs were utilized in four trials (10 replications) at two stations to determine the separate and interacting effects of decreasing floor space allowance with or without the addition of virginiamycin to the diet on performance of growing-finishing pigs. Pigs were allowed .37, .33 or .28 m2/pig during the growing phase (23 to 55 kg) and .74, .66, .56 m2/pig during the finishing phase (55 to 100 kg) and fed either a corn-soybean meal control diet or the control diet plus 11 mg of virginiamycin/kg of diet. Floor space allowances were achieved by varying pen size, so the number of pigs and feeder space per pig were constant for all pens. During the growing phase, daily gain (P less than .01) daily feed intake (P less than .05) and feed conversion ratio (P less than .05) decreased as floor space allowance decreased. During the finishing phase and for the total test period, daily gain (P less than .01) and feed conversion ratio (P less than .05) were reduced but daily feed intake was not affected (P greater than .05) by restricted floor space allowance. The addition of virginiamycin to the diet had no effect on pig performance. The virginiamycin X floor space allowance interaction was not significant, suggesting that pigs fed a diet with or without virginiamycin responded similarly to restricted floor space allowance. The data suggest that the addition of virginiamycin to the diet was ineffective in overcoming the decrease in performance of growing-finishing pigs caused by crowded conditions.     

The interrelationship between crude protein and exogenous porcine somatotropin on growth, feed and carcass measurements of pigs

In three experiments the interrelationship between dietary CP and recombinant porcine somatotropin (rpSt, i.m. daily) on ADG, feed efficiency (F/G) and carcass traits was examined in crossbred Yorkshire gilts and barrows given ad libitum access to their diets during the finishing period (55 to 110 kg BW). Pigs, blocked by BW and gender, were assigned (four/pen) within block. In Exp. 1, 140 pigs were assigned two/gender per pen to each of five pens/block and received a diet of either 12%, 18% or 24% CP (n = 2, 1 and 2 pens/block, respectively). Pigs received rpSt, either 0 or 120 micrograms/kg BW (12% and 24% CP groups) or 60 micrograms/kg BW (18% CP group). When CP was 12%, rpSt decreased ADG and increased F/G (P less than .05), whereas when CP was 18% or 24%, rpSt increased ADG and lowered F/G (P less than .05). Backfat thickness was reduced (P less than .05) by rpSt regardless of CP. In Exp. 2, 120 pigs were assigned two/gender per pen to each of five pens/block and received a diet of 24% CP. Either 0, 15, 30, 60 or 120 micrograms of rpSt/kg BW was administered to each pig. All doses of rpSt increased ADG, lowered F/G and decreased backfat thickness compared with measurements for control pigs (P less than .05). In Exp. 3, 140 pigs were assigned two/gender per pen to each of seven pens/block and received a diet of either 14%, 18% or 24% CP (n = 3, 2 and 2 pens/block, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of a box to prevent agonistic behavior after regrouping in isolated and non-isolated pigs

The effects of a box in the pen on the agonistic behavior of pigs after regrouping was determined in 24 pigs from five litters that were kept in three pens after weaning. For the experiment, the pigs were allocated to six pens with four animals each and kept with their peers for 2 weeks. The lightest pig from each pen was removed and isolated for 2 weeks, and then regrouped with its original peers. At the time of regrouping, half of the pens were equipped with the box. The number and duration of agonistic behavior events were particularly large and long in the pen without a box on the first day after regrouping, and for the isolated pig on the first day (all P  < 0.05). The number of times the box was accessed was large for the isolated pig on the first day after regrouping ( P  < 0.01). The number of agonistic behavior events and the times the box was accessed was correlated on the first day after regrouping ( r _s = 0.79, P  < 0.01). The number of agonistic behavior events on the first day after regrouping was greater in the pens without a box than in the pens with a box ( P  < 0.01). It was suggested that the box had the effect of reducing agonistic behavior after regrouping.     

Interaction of swine nursery and grow-finish space allocations on 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.     

Methionine requirement of the finishing pig

Two pig experiments were conducted using a methionine (Met)-deficient feather meal-corn-soybean meal basal diet (13% CP; 3,400 kcal ME/kg diet, .126% Met, 456% cystine) supplemented with an amino acid mixture (lysine, tryptophan, histidine, threonine and phenylalanine) to determine the Met requirement of finishing pigs between 50 and 80 kg live weight. Using young chicks in a Met bioavailability growth assay and cecectomized adult cockerels in a Met digestibility assay, the Met-deficient basal diet was found to contain .115% bioavailable and .110% digestible Met. These results gave a bioavailability estimate (relative to DL-Met set at 100%) of 91.3 +/- 2.5% and a true digestibility estimate of 87.0 +/- 2.2% for Met in the basal pig diet. In Exp. 1, 21 crossbred pigs averaging 61 kg initially were individually fed diets containing .115, .165 or .215% bioavailable Met for 21 d. Average daily gain and gain:feed ratio increased quadratically (P less than .05) as level of Met increased. In Exp. 2, 30 crossbred pigs averaging 53 kg were individually fed diets containing .115, .135, .155, .175 or .195% bioavailable Met for 27 d. Daily gain and gain;feed ratio responded linearly (P less than .01) as Met level increased. Based on the results of Exp. 2, the bioavailable Met requirement of finishing pigs in the weight range 50 to 80 kg was estimated to be .182% of the diet. Assuming an 88% bioavailability of Met in commercial diets based on corn and soybean meal, the total Met level needed in practice would be .207%. If 55% of the finishing pig's sulfur amino acid need can be furnished by cystine, the total sulfur amino acid requirement would be .45% of the diet.     

Zinc-amino acid complexes for swine

Two experiments were conducted to determine the effect of sources of dietary zinc on gain, feed conversion and blood and bone traits of swine. In the first experiment 96 pigs were used in a 28-d study. The pigs were fed diets with no supplemental Zn or with either 9 or 12 ppm supplemental Zn from zinc sulfate (ZnSO4), zinc methionine (ZnMet) or zinc methionine with picolinic acid (ZnMet w/PA), each with or without 5% added corn oil. There were differences (P less than .05) in average daily gain (ADG) and average daily feed intake (ADFI) between the pigs fed the two organic Zn sources, with those fed ZnMet w/PA showing the better gains and feed conversion. However, neither organic Zn source resulted in pig performance that was different from either the diet with no supplemental Zn or the diets supplemented with Zn from ZnSO4. In the second experiment the same dietary Zn sources and treatments were fed as in Exp. 1 except that corn oil was deleted as a variable. No differences in ADG, ADFI, feed/gain (F/G) or in changes in serum Zn or Cu were observed among treatments during either the 21-d nursery or the 56-d growing periods. During the subsequent 56-d finishing period ADG and ADFI were greater (P less than .01) for pigs fed the Zn-supplemented diets than for those fed the diets without supplemental Zn. There were no differences among treatments in F/G during the finishing period. Zn content of bone ash was lower (P less than .01) in the non-Zn-supplemented pigs. These data suggest that the Zn sources used are of similar biological value and do not support the theory that picolinic acid aids Zn absorption.     

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.     

Influence of an experimental infection of Ascaris suum on performance of pigs

Thirty-two pigs (average 26.6 kg live weight) were individually housed and fed to study the effect of an infection of Ascaris suum (either 0, 600, 6,000 or 60,000 A. suum eggs/pig) on performance of growing-finishing pigs. Increasing the level of A. suum infection produced linear (P less than .07) and quadratic (P less than .09) effects on final weight, weight gain and average daily gain. Feed to gain ratio and number of A. suum worms recovered from the intestines of pigs at slaughter increased linearly (P less than .01) with increasing doses of A. suum eggs. Pigs receiving 60,000 A. suum eggs were 13% less (P less than .01) efficient than the noninfected controls. In each of two trials, eight crossbred barrows (15.7 kg in trial 1 and 16.1 kg body weight in trial 2) were examined for the effects of two levels of A. suum infection (0 and 20,000 eggs/pig) on digestibility coefficients for dry matter, crude protein and gross energy. The infection did not affect (P greater than .05) digestibility coefficients during the first two collection periods (d 6 through 10 and 19 through 23). However, digestion coefficients for dry matter, crude protein and gross energy obtained from the total collection period on d 33 through 37 postinfection were greater (P less than .01) for control pigs than for pigs given 20,000 A. suum eggs each. Also, N retention was greater (P less than .05) for control pigs than for infected pigs.     

The effect of ractopamine hydrochloride on the carcass cutting yields of finishing swine.

This study was designed to evaluate growth performance, carcass cutting yield, and processing characteristics of boneless hams and bellies from finishing pigs fed diets containing 0, 5, 10, or 20 ppm of the phenethanolamine ractopamine hydrochloride (RAC). Sixty pigs were blocked by starting weight and randomly assigned to pens (four pigs/pen) within each of three blocks. Treatments were then randomly assigned to the pens to total six pens of the 0-ppm level and three pens each at the 5-, 10-, and 20-ppm RAC levels. Weight gain and feed consumption were monitored and animals were slaughtered by weight block after approximately 48 d on trial. Slaughter weight, ADG, and feed/gain were improved (P less than .05) for RAC treatments. Dressing percentage was higher and increased linearly (P less than .05) for RAC treatments. Carcass weight, length, leaf fat weight, backfat thickness, loin eye area, and color, marbling, and firmness of the longissimus were evaluated. The RAC-treated carcasses were heavier (P less than .05) and loin eye area increased linearly (P less than .05). One side of each carcass was fabricated using National Association of Meat Purveyors specifications. Trimmed hams and loins from the RAC treatments were heavier (P less than .05) than those from control animals. No differences (P greater than .05) in carcass cutting yield (percentage of trimmed primal cuts) were observed between treatments. However, trimmed hams and loins from the 20-ppm RAC treatment represented a greater (P less than .05) percentage of carcass weight than did those from control animals. Ractopamine did not affect raw belly or bacon characteristics (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of feed and water restriction and receiving diet crude protein on feeder pig performance

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.     

Effects of eating space and availability of water in feeders on productivity and eating behavior of grower/finisher pigs

Three experiments were conducted to determine the effects of eating space and availability of water within feeders on the productivity and behavior of growing/finishing pigs. In Exp. 1, 12 commercial feeders were classified as being either single-space (SS) or multiple-space (MS), and either as dry (D) or wet/dry (WD), resulting in two SS-D, four MS-D, three SS-WD and three MS-WD models. Each model was evaluated using four pens of 12 pigs, which were fed a mash diet throughout the growing/finishing period (25 to 106 kg). Pigs were videotaped when they were approximately 40 and 80 kg in weight to determine eating behavior. The number of feeding spaces did not affect the productivity of the pigs, but the presence of water within the feeder resulted in increases in ADFI (P < .05) and ADG (P < .05) and a reduction in carcass lean (P < .05). Pigs eating from SS feeders spent 15% less time eating than those fed from two-space feeders (P < .05), and occupancy rate for feeding spaces was increased by 75% (P < .05). The WD feeders also resulted in a reduction (17%) in eatingtime compared to D models (P < .01), and occupancy rate for WD feeders was similarly reduced (P < .05). Pigs spent 16% less time eating when they weighed approximately 80 kg than when they weighed 40 kg (P < .01). In Exp. 2, rate of eating was determined during a short test on the same 12 feeder models for both small (48 kg) and large (90 kg) pigs. Large pigs ate faster than small pigs, but eating rate was not affected by feeding space or presence of water in the feeder. In Exp. 3, eating rate was determined for small amounts of dry or wet feed. Premixing water with the feed (1:1 ratio by weight) increased eating speed (P < .01). We concluded that 12 pigs can be fed from a single-space feeder without affecting productivity. The inclusion of water within a feeder decreases time spent eating, but it increases ADFI and ADG. When pigs are small, they spend more time eating, and feeder occupancy rates are higher than when they are large.     

The effect of an adaptation period to soybean oil additions in the diets of young pigs

Utilization of soybean oil (SBO) in swine starter diets and the effect of an adaptation period to SBO on performance was studied in two 4-wk experiments with pigs initially 4 to 5 wk of age. One trial was extended an additional 4 wk and apparent DE was measured during the 4th wk postweaning. Corn-soybean meal-based diets were used in which SBO was substituted for cornstarch at 2, 4 and 6% of the diet in Exp. 1 and at 3 and 6% of the diet in Exp. 2. In Exp. 2, SBO was added either initially (adaptation) or after 2 wk (no adaptation). In Exp. 1 daily gain and efficiency of feed utilization were improved (P less than .05) by adding SBO during wk 3 and 4, but not earlier. Feed intake was not affected by treatment. In Exp. 2, for the initial 4-wk postweaning period, there was no effect of SBO addition on growth rate; feed intake was depressed (P less than .05) when SBO was added at wk 3, and efficiency of feed utilization was improved (P less than .05) for pigs fed SBO without an adaptation period. The primary improvements in performance occurred in the 3rd and 4th wk postweaning, with a tendency for pigs to perform better without an adaptation period. During wk 4, pigs adapted to SBO consumed more (P less than .05) feed but tended to be less efficient (P less than .10) than nonadapted pigs. With or without adaptation, apparent DE was unaffected by SBO additions. Regardless of adaptation period, SBO additions depressed feed intake (P less than .05) and improved efficiency of feed utilization (P less than .01) for the 5- to 8-wk growing phase. In conclusion, adding SBO the first 2 wk postweaning did not improve performance; an adaptation period was not necessary for a performance response from added SBO.     

Dietary energy density and frame size effects on composition of gain in feedlot cattle

Experiments were conducted to evaluate the effects of dietary energy density or genetic background on protein and fat gain of growing cattle. In Exp. 1, 24 Limousin steers were used in a growing-finishing trial. A 2 X 2 factorial arrangement was used with steers randomly allotted to four treatment combinations and fed the following diets: 80% concentrate, high moisture corn-corn silage diet (HI) or a corn silage diet (LO) during both the growing (GRO) and(or) the finishing (FIN) phases. Body composition for both experiments was determined by a deuterium oxide dilution technique. Empty body weight gains were greater (P less than .05) for HI during GRO, FIN and the total trial. Daily protein gains (DPG) were greater (P less than .05) for HI during GRO and FIN, while cattle receiving HI during at least FIN had the greatest (P less than .05) overall DPG. Daily fat gains (DFG) followed the pattern of DPG, being more rapid (P less than .05) for cattle fed HI during either GRO or FIN. Cattle fed the HI diet also tended to be more energetically efficient. In Exp. 2, large frame (LG) and small frame (SM) cattle were used for the evaluation of frame size effects on protein and fat deposition. Steers were individually fed an 80% concentrate, corn-based diet during the entire trial. Average daily gains and daily dry matter intake (P less than .05, P less than .01) were greater for LG, while feed efficiency was similar for both cattle types. Large cattle had greater (P less than .05) DPG than SM cattle, however, DFG were not different. Small frame steers were energetically more efficient (P less than .05), apparently due to composition of gain difference.     

Fumaric and citric acids as feed additives in starter pig diets: effect on performance and nutrient balance

The effect of dietary citric acid (CA) and fumaric acid (FA) on pig weight gain (ADG) and gain/feed (G/F) was studied in two trials using 192 crossbred, 4-wk-old weaning pigs. Three dietary levels (0, 1.5 or 3.0%) of either FA (Trial 1) or CA (Trial 2) with or without an antibiotic supplement (110 mg chlortetracycline, 110 mg sulfamethazine and 55 mg penicillin/kg diet) formed six treatment combinations in each trial. These six diets were fed to two replicate pens of eight pigs each for a 4-wk period. In Trial 1, ADG was improved (P less than .01) during wk 1, and G/F was improved during wk 1 (P less than .01) as well as during wk 1 to 2 (P less than .05) for pigs consuming FA-supplemented diets. In Trial 2, CA had no beneficial influence on ADG during the 4-wk trial. However, feed intake during wk 1 was depressed (P less than .05) by adding CA, as was G/F during wk 1 to 2 (P less than .05). Based on these results, FA was selected to be used in a nutrient balance study. Twelve 4-wk-old weanling pigs were fed one of three diets: control (C), C + 1.5% FA, or C + antibiotic supplement (A). Diet digestible energy (DE), ME and N-corrected ME (MEN) were not different among treatments. Nitrogen balance, percentage N retained and apparent N digestibility were not affected by dietary treatment. Calcium balance and percentage of Ca retained were unaffected by diet.(ABSTRACT TRUNCATED AT 250 WORDS)     

Utilization by growing and finishing pigs of raw soybeans of low Kunitz trypsin inhibitor content

Three trials were conducted to compare acceptance and utilization by growing and finishing pigs of diets containing supplemental protein from either heated, solvent-extracted soybean meal (SBM), raw low-Kunitz trypsin inhibitor soybean (LT) or raw commercially grown Williams cultivar soybean with high Kunitz trypsin inhibitor content (HT). In Trial 1, 36 crossbred pigs, averaging 7 kg in weight, were fed 1) corn-SBM, 2)corn-LT or 3) corn-HT diets for 28 d. Diets were formulated to be isolysinic and to have similar calorie:lysine ratios. Average daily gain and gain/feed were higher (P less than .01) for pigs fed the corn-SBM diet than for pigs fed the corn-LT diet; average daily gain and gain/feed were higher (P less than .01) for the corn-LT diet than for the corn-HT. Average daily feed intake did not differ (P greater than .05) among diets. In Trial 2, 48 crossbred pigs averaging 67 kg were fed diets similar to those in Trial 1 but with lower lysine values. The daily gain (.95 kg) of pigs fed the corn-SBM diet was greater (P less than .05) than for pigs fed the corn-LT diet (.87 kg), which in turn was greater (P less than .05) than for the pigs fed the corn-HT diet (.83 kg). Daily feed intake (kg) and gain/feed were 3.27 and .291, 2.97 and .293, and 3.07 and .270, respectively, for pigs fed the corn-SBM, corn-LT and corn-HT diets. In Trial 3, 18 castrate male pigs averaging 12.4 kg were fed cornstarch-based diets with either SBM, LT or HT as the source of protein.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immunologic reactions of pigs regrouped at or near weaning

Using 64 pigs, 2 experiments (32 pigs each) were conducted to evaluate the effects of regrouping nonlittermate pigs at weaning or 2 weeks after weaning on mitogen-induced lymphocyte blastogenesis, intradermal reactions to phytohemagglutinin, and primary antibody responses to sheep erythrocytes. Plasma cortisol concentrations were determined in all pigs and behavior of regrouped pigs was monitored. Compared with control values, plasma cortisol concentrations were higher in nonlittermate pigs regrouped at weaning (P less than 0.001) or 2 weeks after weaning (P less than 0.01). However, regrouping pigs at weaning or 2 weeks after weaning did not influence lymphocyte blastogenesis, phytohemagglutinin skin-test responses, or antibody titers to sheep erythrocytes. Plasma cortisol concentrations were not related to agonistic behavior in regrouped pigs or to lymphocyte blastogenic or phytohemagglutinin skin-test responses; however, higher plasma cortisol concentrations were related (P less than 0.05) to lower sheep erythrocyte antibody titers. These data indicate that regrouping nonlittermate pigs at weaning or 2 weeks after weaning is an acute stressor that does not detrimentally affect mitogen-induced lymphocyte blastogenesis, intradermal reactions to phytohemagglutinin, or primary antibody responses to sheep erythrocytes.     

Effects of amperozide and azaperone on aggression and productivity of growing-finishing pigs

Levels of aggression, activity and performance were determined in 270 pigs (initial wt 29.8 kg) injected with amperozide (1.0 mg/kg i.m.), azaperone (2.2 mg/kg i.m.) or saline (.1 ml/kg i.m.) immediately prior to mixing. Pigs had ad libitum access to feed in pens of 15, and six pens were allotted to each treatment. Each pen was video-taped for 48 h after injection. Aggression was determined by continuous observation and summarized for each 2-h period. Injuries on the ears and shoulders of each pig were scored prior to injection and 1, 2, 3 and 7 d after treatment. Eating, drinking and lying were determined by scan sampling at 2-min intervals and summarized for each 2-h period. Weight gain, feed consumption and efficiency were determined for periods ending on d 3, 7, 14, 28, 42, 56, 70 and 84. Both drugs reduced total fighting from 309.8 min for saline to 190.7 and 189.6 min for amperozide- and azaperone-treated pens, respectively (P less than .01). Treatment differences in aggression and lying were evident during the initial 6 h only. Amperozide resulted in fewer fights involving two pigs (197.3/pen) than did azaperone (260.2/pen) or saline (298.3/pen) (P less than .05). Injuries to the ears (P less than .01) and total injuries (P less than .05) were less severe in amperozide-treated pigs than in pigs on the other treatments.(ABSTRACT TRUNCATED AT 250 WORDS)     

Supplementation of ammoniated wheat straw: performance and forage utilization characteristics in beef cattle receiving energy and protein supplements.

Two experiments were conducted to evaluate performance and forage utilization characteristics of beef cattle fed ammoniated wheat straw (AWS) unsupplemented except for minerals or supplemented with energy and protein. In Exp. 1, 194 crossbred beef cows (BW = 472 kg) in late gestation were allotted by weight, breed type, and age during two consecutive winters to 12 drylot pens (three pens/treatment) for a 60-d feeding trial. The AWS (3% NH3 wt/wt) was tubground through a 7.6-cm screen, and cows were allowed ad libitum access to the AWS. In Exp. 2, 16 ruminally fistulated Angus x Hereford steers (BW = 300 kg) were blocked by weight and randomized to treatments in a 35-d intake-digestion trial. Daily supplementation treatments in both experiments were Control, no supplemental energy or protein; LSG, 1.36 kg of sorghum grain (SG); HSG, 2.72 kg of SG; and SG + SBM, 1.02 kg of SG + .34 kg of soybean meal (SBM). All animals received .23 kg of mineral mixture formulated to meet a pregnant cow's mineral requirements. Supplements LSG and SG + SBM were fed to provide the same daily ME, and HSG and SG + SBM were fed to provide the same daily CP. Cows were managed as one group during and after calving. In Exp. 1, all supplements increased gain (P less than .01) vs Control, and cows fed SG + SBM had higher (P = .05) gains than those fed LSG. The SG + SBM supplement increased (P less than .01) change in cow body condition score compared with LSG.(ABSTRACT TRUNCATED AT 250 WORDS)