Synthetic maternal pheromone stimulates feeding behavior and weight gain in weaned pigs

One hundred and forty-four pigs were used to determine the effects of a putative synthetic maternal pheromone on behavior and performance of weanling pigs. Each pen of weaned pigs contained three pigs that were given free access to water and feed. Pigs were videotaped in time lapse for 48 h after weaning and weekly body weights and feed disappearances were recorded for 4 wk. Treatments included: a) control (vehicle applied), b) 30 mL of synthetic pheromone applied to the feeder, or c) 10 mL of synthetic pheromone applied to each of three pigs' snouts. Pigs exposed to the synthetic pheromone spent more (P < 0.05) time with their heads in the feeder and less (P < 0.05) time drinking, lying down, or engaged in agonistic behaviors than control pigs. Pigs exposed to the synthetic pheromone were more (P < 0.05) active during the 48-h period of video taping than control pigs. Pigs exposed to the synthetic pheromone (either on the feeder or their snout) had increased (P < 0.01) average daily gain (ADG) and better (P < 0.01) feed:gain ratio than control pigs over the 28-d postweaning period. In conclusion, the putative synthetic pheromone, applied once at weaning, stimulated apparent feeding behaviors, and reduced fighting and apparent drinking behaviors during the first 48 h after weaning. ADG and feed:gain ratio were improved by application of the putative synthetic pheromone either directly on the feeder or when painted on the pigs' snouts. Olfactory signals can modulate adaptation to the postweaning environment in ways that may improve pig performance and welfare.     

Effects of restricted feed intake on finishing pigs weighing between 68 and 114 kilograms fed twice or 6 times daily

In a previous study with limit-fed gestating gilts, we observed that gilts fed 6 times/d had greater ADG than those fed the same amount over 2 feedings. To confirm these earlier responses, we used finishing pigs as a model in two 42-d trials and two 28-d trials to evaluate the effects of restricted feed intake and feeding frequency (2 vs. 6 times/d, floor fed) on pig performance between 68 and 114 kg. In all experiments, pigs (10/pen) were housed in 1.8 × 3.1 m pens with a half-solid, half-slatted concrete floor. Pigs were fed a corn- and soybean meal-based diet formulated to 1.15% standardized ileal digestible Lys and 3,294 kcal of ME/kg. In Exp. 1 to 3, energy and Lys were supplied to pigs according to NRC (1998) calculations to target an ADG of 0.80 kg. In Exp. 4, the diet was supplied to pigs to target an ADG of 0.80 kg (low feed intake) or 0.95 kg (high feed intake) to determine if the amount of energy above the maintenance requirement and feeding frequency affected pig performance. Pigs were fed by dropping similar amounts of feed onto the solid concrete floor either 2 (0700 or 1400 h) or 6 times (3 meals within 2 h at the morning and afternoon feedings) per day with an Accu-Drop Feed Dispenser (AP Systems, Assumption, IL). In Exp. 1 and 2, pigs fed 6 times daily had increased (P < 0.02) ADG and G:F compared with pigs fed 2 times per day. Greater feeding frequency increased (P < 0.05) the duration of time spent feeding and standing and reduced the lying time. In Exp. 3, a third treatment was included to determine whether the improvements in performance were due to decreased feed wastage. This treatment was designed to minimize feed wastage by dropping feed closer to the floor for pigs fed 2 times per day. Pigs fed 6 times daily had improved (P < 0.05) ADG and G:F compared with pigs in either treatment fed 2 times per day. No difference (P > 0.05) in performance was observed between pigs fed 2 times per day when feed was dropped from the feed drop or by the modified method. In Exp. 4, increasing the feeding frequency from 2 to 6 times per day improved (P < 0.01) ADG and G:F for pigs fed the low feed intake and tended to increase (P < 0.06) ADG and improved (P < 0.05) G:F for pigs fed the high feed intake. In limit-feeding situations, increasing the frequency of feeding from 2 to 6 times per day improved pig performance, which confirmed our earlier findings in gestating gilts.     

The effect of meal intervals and weaning on feed intake of early weaned pigs

Feed intake was investigated in early weaned pigs housed in two environments. In the first experiment, pigs in an unfamiliar environment (removed from the sow and placed in nursery pens) were offered a dry diet either ad libitum or at different meal intervals (2, 4 and 6 h). Regardless of meal interval (ad libitum or hourly intervals), early weaned (21 d) pigs failed to consume sufficient feed for maintenance during the first 3 d postweaning. Pigs provided feed ad libitum consumed more (P less than .001) feed (142 vs 84 g/d) and gained more (P less than .05) weight (57 vs 3 g/d) than meal-fed pigs over the 7-d period. Pigs fed at 2-h intervals consumed more (P less than .001) feed than pigs fed at 4-h or 6-h intervals. Compared with preweaning levels (307 mu eq/liter), plasma free fatty acid (FFA) levels increased approximately fourfold by d 1 postweaning (1,372 mu eq/liter), then decreased through d 7 to levels below preweaning (142 mu eq/liter). The FFA levels were not affected (P greater than .1) by meal interval. In a second experiment, feed intake was investigated in weaned pigs that were allowed to consume food by a familiar method and in a familiar environment (suckling the sow). When allowed to nurse following a 24-h weaning period, weaned pigs consumed (24.3 +/- 2.8 g/suckling) the same amount (P greater than .1) as non-weaned littermates (28.7 +/- 1.8 g/suckling).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of creep feed consumption on individual feed intake characteristics and performance of group-housed weanling pigs

To assess the effects of creep feed consumption on individual feed intake characteristics and performance of group-housed weaned pigs, 16 litters (149 piglets) were fed a commercial creep feed (3,040 kcal NE/kg, 15.2 g lysine/kg) supplemented with 1% chromic oxide. Another five litters (48 piglets) were not given access to creep feed (no-feed). Piglets were weaned at 28 d after birth. On d 18, 22, and 27 of age, fecal samples from all the piglets were taken using fecal loops. A green color of the feces indicated that the piglet had eaten creep feed. Piglets that had green-colored feces three times were considered as eaters. Piglets that never showed green-colored feces were considered as non-eaters. At weaning 22 piglets of each type (no-feed, non-eaters, and eaters) were selected based on BW, litter origin, and sex. These 66 pigs were assigned to six pens equipped with computerized feeding stations. Eaters, non-eaters, and no-feed pigs were equally divided over all six pens. After weaning a prestarter (d 0 to 13) and a starter diet (d 14 to 34) were offered for ad libitum consumption. The individual feed intake characteristics of latency time (interval between weaning and first feed intake) and initial feed intake (intake during the first 24 h following first feed intake) and performance traits were determined for all piglets. The pigs that were designated as eaters needed less time between weaning and first feed intake than the pigs that were designated as non-eaters and no-feed pigs (P = 0.04 and P = 0.06, respectively). Initial feed intake was not affected (P > 0.1) by feed intake prior to weaning. However, during d 0 to 8 the eaters had more visits per day during which feed was consumed than both the non-eaters and no-feed pigs. Averaged over the first 8 d after weaning, the ADFI and ADG of the eaters were higher than that of the non-eaters and no-feed pigs (P < 0.05). Averaged over the total 34-d period the effect of creep feed intake on postweaning ADFI was much less pronounced (P = 0.20), whereas ADG of the eaters was the highest (P < 0.05). Creep feed intake during the sucking period stimulates early postweaning feed intake as well as postweaning performance.     

Effect of glutamine and spray-dried plasma on growth performance, small intestinal morphology, and immune responses of Escherichia coli K88+-challenged weaned pigs

Forty weaned barrows (5.32 +/- 0.3 kg BW) at 17 +/- 2 d of age were used to investigate the effects of feeding glutamine and spray-dried plasma on the growth performance, small intestinal morphology, and immune responses of Escherichia coli K88-challenged pigs. Pigs were allotted to four treatments including: 1) nonchallenged control (NONC); 2) challenged control (CHAC); 3) 7% (as-fed basis) spray-dried plasma (SDP); and 4) 2% (as-fed basis) glutamine (GLN). On d 11 after weaning, all pigs were fitted with an indwelling jugular catheter. On d 12 after weaning, pigs in the CHAC, SDP, and GLN groups were orally challenged with skim milk E. coli K88 culture, whereas pigs in the NONC group were orally inoculated with sterilized skim milk. Rectal temperatures and fecal diarrheic scores were recorded and blood samples collected at 0 (baseline), 6, 12, 24, 36, and 48 h after the challenge for serum hormone and cytokine measurements. At 48 h postchallenge, all pigs were killed for evaluation of small intestinal morphology. There was no effect of feeding SDP or GLN on growth performance during the 11-d prechallenge period (P = 0.13). At 48 h after the challenge, CHAC pigs had decreased ADG (P = 0.08) and G:F (P = 0.07) compared with the NONC pigs; however, SDP and NONC pigs did not differ in G:F, and GLN and NONC pigs did not differ for ADG and G:F. At 6, 36, and 48 h after the challenge, CHAC, SDP, and GLN pigs had increased rectal temperature relative to the baseline (P = 0.09). At 12 and 36 h after the challenge, CHAC pigs had the highest incidence of diarrhea among treatments (P = 0.08). Serum IL-6 and ACTH were not affected by treatment or time after E. coli challenge (P = 0.11). In proximal, midjejunum, and ileum, CHAC pigs had greater villous atrophy and intestinal morphology disruption than NONC pigs (P < 0.01), whereas SDP and GLN pigs had mitigated villous atrophy and intestinal morphology impairment after E. coli challenge. Pigs in the SDP had the lowest GH at 12 h and the greatest GH at 36 h after the challenge among treatments (P = 0.08). Pigs in the NONC had the highest IGF-1 at 12 and 36 h postchallenge (P < 0.04). These results indicate that feeding glutamine has beneficial effects in alleviating growth depression of E. coli K88-challenged pigs, mainly via maintaining intestinal morphology and function, and/or possibly via modulating the somatotrophic axis.     

Relationship between weaning age and antibiotic usage on pig growth performance and mortality

A total of 2,184 pigs (DNA 600 × PIC L42) were used to evaluate the effects of weaning age and antibiotic (AB) use on pig performance from weaning to marketing in a commercial production system. Experimental treatments were arranged in a 3 × 2 factorial with main effects of weaning age (18.5, 21.5, or 24.5 d of age) and with the use of ABs or an antibiotic-free (NAE) program. At birth, pigs were ear tagged, and the date of birth and sex recorded. Pigs were weaned from a 4,000-sow farm over four consecutive weeks. Four weaning batches (one per week) of 546 pigs were used. Each weaning batch had one-third of pigs of each weaning age. Pigs were placed in pens by weaning age and then randomly assigned to an AB or NAE program. There were 14 replicate pens per treatment and 26 pigs per pen (13 barrows and 13 gilts). Pigs allocated to the AB program were fed a diet containing 441 mg/kg chlortetracycline (CTC) from day 8 to 21 postweaning. They were also administered 22 mg/kg of body weight (BW) of CTC via drinking water for five consecutive days after a porcine respiratory and reproductive syndrome outbreak during week 7 after weaning. In the first 42 d postweaning, increasing weaning age improved (linear, P < 0.001) BW at day 42, average daily gain (ADG), and average daily feed intake (ADFI). From weaning to 197 d of age, increasing weaning age increased (linear, P < 0.001) ADG and ADFI. Pigs on the AB program had greater (P = 0.031) ADG and ADFI compared with NAE pigs. An interaction (linear, P = 0.005) was observed for feed efficiency (G:F). When ABs were provided, increasing weaning age did not result in any change in G:F; however, in the NAE program, increasing weaning age increased G:F. Pigs on the AB program had lower (P < 0.001) total losses (mortality and removals) than those on the NAE program. Increasing weaning age marginally (linear, P = 0.097) decreased total losses. Increasing weaning age decreased (quadratic, P < 0.001) the number of pigs treated with an injectable AB but the AB program did not (P = 0.238). The weight sold (at 197 d of age) per pig weaned was increased (linear, P = 0.050) by increasing weaning age and by using AB in feed and water (P = 0.019). In summary, increasing weaning age linearly improved most of the pig performance criteria and relatively the short-term use of ABs reduced mortality and removals with both factors contributing to increased weight sold per pig weaned.     

Influence of two supplemental vitamin E levels and weaning age on performance, humoral antibody production and serum cortisol levels of pigs

Three trials using 156 Yorkshire x Hampshire x Duroc crossbred pigs (avg initial wt, 7.9 kg) were conducted to evaluate the effects of two supplemental dietary vitamin E (11 vs 220 IU/kg of diet) and weaning age (21, 28 or 35 d) on performance and immunocompetence of pigs. Supplemental vitamin E (220 IU/kg of diet) increased (P less than .01) serum concentrations of vitamin E for all weaning ages compared with pigs fed 11 IU of vitamin E/kg of diet. However, supplemental vitamin E did not affect performance, serum cortisol concentration or the primary and secondary antibody response to sheep red blood cells. As weaning age increased, weekly ADG and avg daily feed intake increased linearly (P less than .01). Cortisol levels decreased during the 1st wk following weaning and then increased linearly (P less than .01) over time; pigs weaned at 35 d of age had higher (P less than .01) cortisol values initially and over time than pigs weaned at 21 and 28 d. Pigs weaned at 35 d had a higher (P less than .01) primary response to sheep red blood cells than pigs weaned at 21 and 28 d of age, but this effect was not observed for the secondary response. There were no interactive effects (P greater than .10) of dietary vitamin E level and weaning age. In summary, the highest level of supplemental vitamin E increased serum vitamin E concentration but did not affect performance, cortisol levels or one test of the immune response, antibody titers to red blood cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Ornithine alpha-ketoglutarate and creatine effects on growth and plasma metabolites of nursery pigs

Four experiments were conducted to determine the effect of dietary ornithine alpha-ketoglutarate (OKG) and creatine monohydrate on growth performance and plasma metabolites of nursery pigs. In each experiment, treatments were replicated with four to five pens of four to six pigs each. Each experiment lasted from 3 to 4 wk and Phase I (1.6% Lys) and Phase II (1.3 to 1.5% Lys) diets were fed for 9 to 16 d each. In Exp. 1, pigs (4.7 kg and 15 d of age) were fed diets containing 0, .10, or .75% OKG. Daily gain during a 13-d Phase I period and ADFI during Phase I and overall (29 d) were increased (P < .10) in pigs fed .75% OKG. Gain:feed ratio was not affected (P > .10) by diet. In Exp. 2, pigs (7.1 kg and 23 d of age) were fed 0 or .50% OKG during Phase I only. During Phase I, II, and overall, ADG and ADFI were not affected (P > .10) by OKG supplementation, but gain:feed was decreased during Phase I (P < .04), Phase II (P < .08), and overall (P < .04). Plasma urea N (PUN), glucose, and NEFA concentrations were not affected (P > .10) by OKG supplementation in this experiment. In Exp. 3, pigs (5.8 kg and 20 d of age) were fed diets containing 0, .10, or .50% creatine. Creatine tended to linearly decrease ADG (P = .11) and plasma albumin (P = .12) and PUN (P < .10) concentrations in Phase II (d 12 to 26). In Exp. 4, 850 mg of OKG or 750 mg of creatine was provided daily by oral capsule to pigs 4 d before weaning to 2 d after weaning. Pigs within a litter received either no capsule or capsules containing OKG or creatine. After weaning, pigs that received no capsule before weaning received no treatment, .50% creatine, or .50% OKG in the nursery diet. Pigs that received OKG before weaning received no treatment or .50% OKG, and pigs that received creatine before weaning received no treatment or .50% creatine in the nursery diet. Pigs weighed 3.9 kg 4 d before weaning and 4.9 kg at weaning at an average age of 20 d. The OKG provided by capsule decreased ADG (P < .02) and ADFI (P < .09) during Phase II. The OKG did not affect (P > .10) plasma NEFA, glucose, or urea N concentrations. Creatine added to the nursery diet increased (P < .02) ADFI and decreased (P < .10) gain:feed during Phase II and overall. Creatine in the nursery diet also increased (P < .01) PUN, but it did not affect plasma glucose or NEFA concentrations. Creatine and OKG have variable effects on growth performance and plasma metabolites of nursery pigs.     

Individually measured feed intake characteristics and growth performance of group-housed weanling pigs: effects of sex, initial body weight, and body weight distribution within groups

Feed intake characteristics of 192, 27-d-old weanling pigs housed in groups and given ad libitum access to feed and water were measured individually with the use of computerized feeding stations. The groups were either homogeneous or heterogeneous as to BW distribution; pigs of three defined initial BW classes were used (mean BW of 6.7, 7.9, or 9.3 kg). The effects of BW distribution, BW class, and sex were studied with regard to average performance traits, latency time (interval between weaning and first feed intake), initial feed intake (intake during the first 24 h following first feed intake), and daily increase in feed intake during the interval between first feed intake and the day on which energy intake met or exceeded 1.5 times the maintenance requirement. Homogeneous and heterogeneous groups had similar latency times, initial feed intakes, and daily increases in feed intake. For the period 0 to 34 d after weaning, ADFI and ADG were also similar for homogeneous and heterogeneous groups, but gain:feed ratio was greater (P < 0.05) in the homogeneous groups. Gilts had higher (P < 0.05) initial feed intakes than barrows and also had greater (P < 0.05) ADFI and ADG during the period 0 to 13 d after weaning. Pigs with average BW of 6.7 kg had higher (P < 0.05) initial feed intakes than their counterparts with average BW of 7.9 kg and 9.3 kg, but the daily increase in feed intake was similar for the three groups. The lighter pigs had more daily visits and a lower feed intake per visit and tended to have a shorter postweaning latency to the onset of feeding than the heavier pigs. This study indicates that the high variability in early feeding behavior among group-housed weanling pigs may be related to BW and sex.     

Effect of feed and(or) water deprivation prior to weaning on reproductive performance of sows: a cooperative study

A total of 292 sows, at three experimental stations (Auburn, Texas A&M, Texas Tech), was used to determine the effects of depriving sows of feed and(or) water before weaning on reproductive performance. The four treatments were arranged as a 2 X 2 factorial to evaluate two periods of feed deprivation (0 and 48 h) and two periods of water deprivation (0 and 24 h) before weaning. Sows were allowed to consume feed ad libitum during lactation, and were fed 1.8 kg/d during the weaning to breeding interval. Only sows nursing six or more pigs at weaning were used. Pigs were weaned at approximately 42 d at Auburn and 28 d at Texas A&M and Texas Tech. Treatment responses were similar at each station with no evidence of a station X treatment interaction for any of the traits (P greater than .10). During the 48-h treatment period, sows receiving feed and water ad libitum lost 1 kg compared with weight losses of 16 kg for sows deprived of feed for 48 h, 13 kg for sows deprived of water for 24 h, and 17 kg for sows deprived of feed for 48 h and water for 24 h. Weight losses for sows deprived of water only, may have partially resulted from reduced feed intake during the 24-h treatment period; however, feed intake during this period was not measured. At breeding, sows deprived of feed and(or) water maintained their greater weight losses, suggesting that some tissue loss occurred during the 48- or 24-h treatment periods.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of providing a water-soluble globulin in drinking water and diet complexity on growth performance of weanling pigs

Two experiments were conducted to evaluate the effects of providing a water-soluble globulin in the drinking water on growth performance of weanling pigs. In Exp. 1, 360 weanling pigs (5.0 +/- 1.2 kg; 17 +/- 3 d of age; PIC) were blocked by initial weight and allotted to one of six treatments in a 2 x 3 factorial arrangement. Treatments included three diet complexity regimens with or without water-soluble globulin (3 and 1.5% solutions; d 0 to 7 and d 0 to 14, respectively) provided in the drinking water. The 35-d study was divided into three phases (d 0 to 7, 7 to 14, and 14 to 35) with corresponding lysine levels of 1.6, 1.5, and 1.35%. Soybean meal replaced specialty protein and lactose sources to provide three different complexity regimens. From d 0 to 7, a water-soluble globulin x diet complexity interaction (P < 0.05) was observed for average daily gain (ADG) and gain:feed (G/F). Increasing diet complexity increased ADG and G/F for pigs provided water, whereas the medium diet complexity regimen optimized performance for pigs offered water-soluble globulin. From d 0 to 14, pigs fed the two more complex regimens had greater ADG and G/F (P < 0.01) than the pigs fed the least complex regimen. Pigs offered water-soluble globulin had decreased (P < 0.01) ADFI, but increased (P < 0.001) G/F from d 0 to 14. For overall performance (d 0 to 35), increasing diet complexity increased (P < 0.03) ADG and ADFI, whereas water-soluble globulin offered from d 0 to 14 had no effect. In Exp. 2, 360 weanling pigs (5.2 +/- 1.6 kg; 19 +/- 4 d of age) were used in a 21-d growth assay. The trial was arranged as a 2 x 3 factorial with pigs fed the low- or medium-complexity diets (Exp. 1) with water or a 3% solution of water-soluble globulin offered for 4 or 8 d after weaning. From d 0 to 4, pigs offered water-soluble globulin had increased (P < 0.001) ADG and G/F compared with pigs provided water, whereas from d 4 to 8, pigs provided water had increased (P < 0.05) ADG and G/F compared with pigs offered water-soluble globulin. Pigs fed the medium-complexity diet had increased ADG and G/F (d 4 to 8 and d 8 to 12) compared with pigs fed the low-complexity diet. From d 0 to 8 and d 0 to 21, pigs provided water-soluble globulin for 4 or 8 d after weaning had improved G/F compared with pigs provided water. Results demonstrate that providing water-soluble globulin through the water source of weanling pigs improves ADG and G/F immediately after weaning.     

Early- and traditionally weaned nursery pigs benefit from phase-feeding pharmacological concentrations of zinc oxide: effect on metallothionein and mineral concentrations.

Benefits of feeding pharmacological concentrations of zinc (Zn) provided by Zn oxide (ZnO) to 21-d conventionally weaned pigs in the nursery have been documented; however, several management questions remain. We conducted two experiments to evaluate the effect on growth from feeding 3,000 ppm Zn as ZnO during different weeks of the nursery period. In Exp. 1 (n = 138, 11.5 d of age, 3.8 kg BW) and Exp. 2 (n = 246, 24.5 d of age, 7.2 kg BW), pigs were fed either basal diets containing 100 ppm supplemental Zn (adequate) or the same diet with an additional 3,000 ppm Zn (high) supplied as ZnO. Pigs were fed four or two dietary phases in Exp. 1 and 2, respectively, that changed in dietary ingredients and nutrient content (lysine and crude protein) to meet the changing physiological needs of the pigs for the 28-d nursery period. Dietary Zn treatments were 1) adequate Zn fed wk 1 to 4, 2) high Zn fed wk 1, 3) high Zn fed wk 2, 4) high Zn fed wk 1 and 2, 5) high Zn fed wk 2 and 3, and 6) high Zn fed wk 1 to 4. In Exp. 1 and 2, pigs fed high Zn for wk 1 and 2 or the entire 28-d nursery period had the greatest (P < .05) ADG. During any week, pigs fed high Zn had greater concentrations of hepatic metallothionein and Zn in plasma, liver, and kidney than those pigs fed adequate Zn (P < .05). In summary, both early- and traditionally weaned pigs need to be fed pharmacological concentrations of Zn provided as ZnO for a minimum of 2 wk immediately after weaning to enhance growth.     

Evaluation of sex and lysine during the nursery period

Split-sex feeding in the grow-finish period of swine production was an innovative technology of the last decade because of the different growth rates, feed efficiencies, and perhaps different nutrient needs between gilts and barrows. However, due to various weaning strategies, split-sex feeding has not been adequately evaluated in the nursery. The objectives of our research were to determine 1) if gilts and barrows responded similarly to increased protein (Lys) after weaning, and 2) if the current NRC estimated requirements for Lys are adequate. Six experiment stations (KS, KY, MI, MN, OH, and SD) utilized 748 pigs (6.7 kg of BW; 19.4 +/- 1.1 d of age). The pigs were allotted to 4 treatments in 32 replications (5 to 7 pigs/pen) in a randomized complete block design. Barrows and gilts were penned separately, and complex nursery diets were fed in 3 phases (d 1 to 7, 8 to 21, and 22 to 35). Lysine was provided at the NRC estimated requirements or at 0.20% greater (1.35 vs. 1.55%, 1.25 vs. 1.45%, and 1.15 vs. 1.35% for the 3 phases, respectively). Pigs and feed were weighed initially and at the end of each phase. The results demonstrated that sex did not affect ADG, ADFI, or G:F in any phase or during the 35-d study (453 vs. 452 g/d, 674 vs. 675 g/d, and 0.673 vs. 0.671 for barrows and gilts, respectively). The greater Lys concentration improved ADG in phase 3 (628 vs. 589 g; P < 0.001) and overall (465 vs. 441 g; P < 0.001) compared with pigs fed the NRC-estimated Lys requirements. Increased Lys in the diet increased ADFI in phase 2 (P < 0.05), but not in the other phases or for the overall 35-d study. Gain:feed was improved by feeding greater Lys concentrations in phase 2 (0.785 vs. 0.704; P < 0.001) and in the overall 35-d experiment (0.695 vs. 0.649; P < 0.001). There was no evidence of a sex x Lys interaction (P = 0.33) for any of the response variables during any of the phases or overall. Our results demonstrate that increasing Lys concentrations in nursery diets results in improved pig performance of both sexes, and there appears to be no benefit to split-sex feeding when mixed genotypes are fed in the nursery.     

Effects of replacing pharmacological levels of dietary zinc oxide with lower dietary levels of various organic zinc sources for weanling pigs

Two 28-d randomized complete block design experiments were conducted to evaluate the effects of concentrations and sources of Zn on growth performance of nursery pigs. Seven stations participated in Exp. 1, which evaluated the efficacy of replacing 2,500 ppm of Zn from ZnO with 125, 250, or 500 ppm of Zn from Zn methionine. A control diet with 125 ppm of supplemental Zn was included at all stations. A total of 615 pigs were used in 26 replicates. Average weaning age was 20.6 d and the average initial BW was 6.3 kg. There were no differences in any growth response among the three supplemental Zn methionine levels fed in Exp. 1. Zinc supplementation from Zn methionine improved ADG compared with the control during all phases (P < 0.05), due primarily to an increase in ADFI. Pigs fed 2,500 ppm of Zn from ZnO gained faster (P < 0.01) than those fed the control diet during all phases, and faster (P < 0.05) than those fed supplemental Zn from Zn methionine for the 28-d experiment. Differences in gain were again due mainly to differences in feed intake. A second experiment compared five sources of supplemental organic Zn (500 ppm of Zn) with 500 and 2,000 ppm supplemental Zn from ZnO and a control (140 ppm total Zn). Six stations used a total of 624 pigs, with an average weaning age of 20.4 d and averaging 6.2 kg BW in 15 replicates. Pigs fed 2,000 ppm of Zn from ZnO gained faster (P < 0.05) than pigs fed the control or any of the 500 ppm of Zn treatments (ZnO or organic Zn). Pigs fed the 2,000 ppm of Zn from ZnO also consumed more feed than those receiving 500 ppm of Zn from ZnO or from any of the organic Zn sources (P < 0.05). Organic sources of Zn did not improve gain, feed intake, or feed efficiency beyond that achieved with the control diet. Supplemental Zn at a concentration of 500 ppm, whether in the form of the oxide or in an organic form, was not as efficacious for improved ADG as 2,000 to 2,500 ppm of Zn from ZnO.     

Effect of drinker type and sound stimuli on early-weaned pig performance and behavior

Early-weaned pigs appear to be highly motivated to engage in motor patterns associated with nursing, which is thought to lead to the development of abnormal ingestive behaviors. If performance of these behaviors is related to sucking motivation, then the normal stimuli associated with nursing should stimulate pigs to perform these abnormal behaviors, specifically belly nosing. The goal of this study was to determine whether belly nosing could be affected by sow nursing vocalizations and whether the style of the drinker device influenced early-weaned pig behavior. Over six trials, 352 Yorkshire pigs were weaned at 15 d and assigned to pens (n = 44) of eight pigs based on litter, weight, and sex. Four pens in each of two rooms were outfitted with either a water nipple drinker or a drinker bowl. Rooms either had recorded sow vocalizations broadcast at hourly intervals or no sound (control). Pig behaviors were videotaped in a sample of pens (n = 32) on d 0, 1, 2, 5, 9, 11, 13, 16, and 18 after weaning. On d 0 to 2, pigs were observed continuously for feeding and drinking behaviors. On d 5 to 18, pigs were observed by scan sampling every 5 min for time budgets. Pigs with drinker bowls had higher apparent feed intakes during the first 2 d after weaning (P = 0.024), whereas they spent less time engaged in drinking behavior (P = 0.001). This coincided with an overall lower water use (P = 0.001) than that of pigs with nipple drinkers. Pigs with bowl drinkers also spent less time belly nosing than those with access to a nipple drinker (P = 0.012). Pigs in the sow vocalization treatment tended to have a higher ADG (P = 0.075), whereas they spent less time performing feeding behavior (P = 0.064). However, there was no effect of sow nursing grunts on belly nosing. These results suggest that there is a complex relationship between feeding, drinking and sucking, and belly nosing is not controlled by the same external stimuli as sucking. Because drinker type and the motor patterns that it accommodates affect belly nosing, it may be that the internal stimuli associated with nursing, such as the actual act of sucking, play a large role in the development of abnormal oral-nasal behaviors.     

Effects of feeding Salmonella enterica serovar Typhimurium or serovar Choleraesuis on growth performance and circulating insulin-like growth factor-I, tumor necrosis factor-alpha, and interleukin-1beta in weaned pigs

The most common Salmonella serovars causing clinical disease in pigs are Salmonella enterica serovars Typhimurium (Typhimurium) and Choleraesuis. Given that the swine host-adapted serovar Choleraesuis has been reported to cause systemic disease, a different disease outcome from that of Typhimurium, our working hypothesis was that this serovar would likely engage systemic immune-inflammatory mechanisms, resulting in elevated systemic cytokine secretion. Forty-eight weaned pigs were blocked by BW and sex, and randomly allotted to 1 of 3 treatments in a 14-d study. Each treatment had 8 replicates (pens), with 2 pigs/pen. The treatments consisted of a negative control and pigs repeatedly fed 10(8) cfu of Typhimurium or Choleraesuis. On d 0, the pigs were fed Choleraesuis or Typhimurium in dough balls, and the bacteria were refed twice weekly throughout the experiment. Control pigs received dough balls without bacteria. All pigs were housed in temperature-controlled rooms under constant lighting and were fed a standard corn-soybean meal-based nursery diet. Pig BW and feed disappearance were used to determine ADG, ADFI, and G:F. Rectal temperatures were obtained daily from 1 pig/pen beginning 2 d before the first bacterial feeding through d 7 using rapid-response digital thermometers. Serum was collected on d 0, 7, and 14 from a single pig/pen for analysis of IGF-I, tumor necrosis factor-alpha , and IL-1beta. There was no change in the rectal temperature of the control or the Typhimurium-challenged pigs (compared with d 0) or when comparing Typhimurium-challenged pigs with control animals. In contrast, pigs fed Choleraesuis had increased rectal temperatures beginning on d 2 and continuing through d 7 (P < 0.05), with the greatest elevation on d 3 (P < 0.001) compared with the control pigs. Average daily gain and ADFI of pigs challenged with Typhimurium did not differ from those of the control animals. Pigs fed Choleraesuis had a 25% reduction in ADG (P < 0.0001) and ADFI (P < 0.002) compared with the control pigs. On d 7, pigs fed Choleraesuis had reduced serum IGF-I compared with control (P < 0.01) or Typhimurium-challenged pigs (P = 0.01). Bacterial feeding did not affect serum tumor necrosis factor-alpha or IL-1beta compared with control pigs at any time throughout the experiment. We conclude that repeated exposure of weaned pigs to Choleraesuis reduced growth performance in the absence of changes in systemic inflammatory cytokines.     

Effect of weaning age and postweaning feeding programme on the growth performance of pigs to 10 weeks of age

This study aimed to determine the effects of weaning age and postweaning feeding programme on pig performance and health. In experiment 1, 96 same gender pairs of pigs weaned at 3, 4 and 5 weeks of age were used in a 3 (weaning age)×4 (dietary programme) factorial design experiment. Pigs received different amounts of a phase 1 diet (16.2 MJ/kg digestible energy (DE) and 16.2 g/kg lysine) and phase 2 diet (15.3 MJ/kg DE and 15.0 g/kg lysine): (A) very low (VL, 1 kg phase 1 and 3 kg phase 2 diet per pig); (B) low (L, 2 kg phase 1 and 6 kg phase 2 diet per pig); (C) medium (M, 3 kg phase 1 and 9 kg phase 2 diet per pig) or (D) high (H, 4 kg phase 1 and 12 kg phase 2 diet per pig), followed by a cereal based phase 3 diet (15.0 MJ/kg DE and 13.8 g/kg lysine) to 10 weeks of age. In experiment 2, faecal samples from 60 pigs weaned at 3, 4 and 5 weeks of age were collected at 10 days postweaning and analysed for Escherichia coli and lactic acid bacteria counts. In experiment 1, there were no interaction effects of age×dietary programme on growth performance. Dietary programme did not affect growth performance from weaning to 10 weeks of age. From weaning to 10 weeks of age, increasing weaning age increased average daily gain (ADG; 363, 402, and 476 g for 3, 4 and 5 weeks respectively; s.e. 17.6; P<0.001), average daily feed intake (ADFI; 560, 620, and 680 g; s.e. 26.1; P<0.001), and improved feed conversion ratio (FCR; 1.57, 1.55, and 1.43; s.e. 0.045; P<0.05). However, weaning age had no effect (P>0.05) on pig weight at 10 weeks of age. In experiment 2, 3 week weaned pigs had higher faecal counts of E. coli (P<0.05) than 4 week weaned pigs and higher faecal counts of lactic acid bacteria (P>0.01) than 5 week weaned pigs at 10 days postweaning. In conclusion, feeding higher amounts of phases 1 and 2 diets did not affect performance at any of the weaning ages tested. Increasing weaning age increased growth performance between weaning and 10 weeks of age, but had no effect on the resulting body weight. Pigs weaned at 3 weeks of age had increased counts of selected faecal bacteria compared to those weaned later.     

Effect of nutritional status, age at weaning and room temperature on growth and systemic immune response of weanling pigs

Two experiments were conducted to determine the effect of nutritional status, age at weaning and room temperature on growth and immune response of pigs. In the first experiment, 72 pigs were weaned at either 2 or 3 wk and fed either a complex, simple-adequate or simple-inadequate diet for a 24-d period. Total antibody (TAb) titers in response to injections of human red blood cells (RBC) on either 0, 4, or 16 d postweaning were not affected by age at weaning or dietary treatments even though the nutritional status was compromised to such an extent that pigs fed the simple-adequate diet gained at one-half the rate (.172 vs .349 kg/d) of pigs fed the complex or simple-adequate diets (P less than .01). In Exp. 2, the immunological response of 144 pigs weaned at 3 wk were evaluated at 4 and 8 d postweaning. Pigs were weaned into rooms that averaged either 25 or 18 C, and were fed either a complex or simplex-adequate diet at either ad libitum (AL) or restricted (Res) levels for a 24-d period. Restriction of either the complex or simple diet for the first 16 d of the trial drastically reduced (P less than .01) the growth rates of Res pigs compared with AL pigs (.042 vs .236 kg/d). There were no differences in skinfold thickness (Sf) or TAb, 2-mercaptoethanol sensitive (MEs) and resistant (MEr) antibody titers when pigs were inoculated with phytohemagglutinin-P (PHA-P) or RBC at 4 d postweaning regardless of room temperature, diet source or feeding level.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of temperature on the performance of finishing swine: II. Effects of a cold, diurnal temperature on average daily gain, feed intake, and feed efficiency

Forty-eight crossbred barrows and gilts weighing 84.5 +/- .33 kg were used during two 21-d trials to investigate the effects of a cold, diurnal temperature (CD; -5.0 to 8.0 degrees C) compared with a constant, thermoneutral temperature (TN; 20 degrees C) and the effects of sex (barrows vs gilts) on performance. A second objective was to determine shrinkage as a result of a 24-h fast immediately after the 21-d study of hogs commingled vs those not commingled for both environmental treatments (CD vs TN). Pigs housed in the CD chamber gained 27.2% more slowly (P less than .001; 75 vs 1.03 kg/d) than those in the TN environment and consumed 5.7% more feed (P less than .05; 3.88 vs 3.67 kg/d). The lower ADG and higher feed intake (FI) exhibited by the CD pigs resulted in poorer (P less than .05) feed efficiency (F/G; 5.33 vs 3.73, respectively). A temperature x sex interaction occurred for ADG but not for FI or F/G. Twenty-four-hour shrink for the CD pigs was 16.4% less than for the TN pigs (3.72 vs 4.45%, respectively); however, commingling did not affect shrinkage.     

Increasing weaning age improves pig performance in a multisite production system

Two trials were conducted to determine the effects of weaning age on pig performance in a multisite production system. The second trial also evaluated the effects of modifying the nursery feeding program according to weaning age. In Trial 1 (2,272 pigs), treatments included weaning litters at 12, 15, 18, or 21 d of age. In Trial 2 (3,456 pigs), litters were weaned at 15, 16, 18, 19, 21, or 22 d of age and categorized into three treatments (15.5, 18.5, or 21.5 d of age). In Trial 2, pigs in each age group were fed one of two nursery feeding programs. Nursery feeding programs varied in both diet formulation and in the quantity of diets fed containing increased levels of whey and spray-dried animal plasma. Each trial was conducted as a randomized complete block design with four blocks of nursery and finishing sites. All weaning-age treatments were weaned from a 7,300-sow farm on the same day into the same nursery. Each block remained intact as pigs moved from nursery to finishing site. Increasing weaning age (12, 15, 18, or 21 d in Trials 1; and 15.5, 18.5, or 21.5 d in Trial 2) increased (linear, P < 0.001) ADG (299, 368, 409, 474 +/- 7 g/d; 435, 482, 525 +/- 13 g/d) and tended to decrease (linear, P < 0.09) mortality (5.25, 2.82, 2.11, 0.54 +/- 0.76%; 2.17, 1.56, 1.30 +/- 0.36%) in the initial 42 d after weaning. Finishing ADG (722, 728, 736, 768 +/- 11 g/d; 783, 790, 805 +/- 11 g/d) also improved (linear, P < 0.01) with increasing weaning age. Overall, increasing weaning age increased (linear, P < 0.001) wean-to-finish ADG (580, 616, 637, 687 +/- 8 g/d; 676, 697, 722 +/- 6 g/d), weight sold per pig weaned (94.1, 100.5, 104.4, 113.1 +/- 1.3 kg; 107.6, 111.6, 116.2 +/- 1.1 kg), and decreased (linear, P < 0.03) mortality rate (9.4, 7.9, 6.8, 3.6 +/- 0.95%; 3.9, 3.4, 2.5 +/- 0.5%). Altering the nursery feeding program did not affect wean-to-finish growth performance. In this multisite production system, increasing weaning age from 12 to 21.5 d of age increased weight sold per pig weaned by 1.80 +/- 0.12 kg for each day increase in weaning age. These studies suggest increasing weaning age up to 21.5 d can be an effective management strategy to improve wean-to-finish growth performance in multisite pig production.