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1.
Abstract

The nutritional contributions from free-range foraging, growth, feed conversion and behaviour were investigated in 36 growing pigs foraging on Jerusalem artichokes (JA) and fed concentrates restrictedly (30% of energy recommendations) or ad libitum. Compared to the ad libitum fed pigs, the pigs fed restrictedly had a significant lower daily gain (560 vs. 1224 g pig?1), improved feed conversion ratio (17.6 vs. 42.8 MJ ME concentrate kg?1 live weight gain) and spent more time foraging JA tubers (7.9 vs. 1.1%). It is estimated that pigs fed restrictedly found approximately 60% of their energy requirement from foraging in the range.  相似文献   

2.
Nose ringing of outdoor sows is practiced to reduce grass sward damage for environmental reasons but conflicts with natural behaviour considerations. We investigated effects of ringing pregnant and lactating outdoor sows on foraging and explorative behaviour, grass cover and nutrient deposition. The experiment included both ringed and unringed sows. For unringed sows the paddocks were either used continuously throughout the experiment or divided into two and sows were moved half way through the experimental period leaving the first used paddock for regrowth. Ringing did not prevent the sow's rooting, but rooting was less pronounced, when sows were ringed. On average, ringing increased grass cover from 14% to 38% and from 64% to 81% in paddocks with pregnant and lactating sows, respectively. In paddocks with unringed sows kept at a double density and followed by a resting period, the grass cover in autumn was restored to a high degree in paddocks with pregnant sows. In lactating sow paddocks the level of inorganic N was high but with no significant relation to extent of grass cover. In pregnant sow paddocks the soil inorganic N content was significantly reduced by increased grass cover and at 60% grass cover soil inorganic N content was at a low level. From the experiment it was evident that although ringing did have a positive environmental effect, it was not the main factor influencing potential losses. Management choices in terms of feeding, animal density and nutrient distribution are considered to be at least as important.  相似文献   

3.
A study was carried out to determine voluntary forage intake and nutrient digestibility in growing pigs fed a mixed forage and concentrate diet. Twenty-five 8-week-old Large White?×?Landrace crossbred male pigs (27?±?3.8?kg) were blocked by weight into five groups, and each was randomly allocated to four indoor treatments (A, B, C, and D), which received 100, 90, 80, and 70?% of ad lib concentrated intake and an outdoor treatment (E) that received 80?% of ad lib concentrate. Indoor treatments were either fed the concentrate only (A) or also received freshly cut Kikuyu grass (Pennissetum clandestinum) ad libitum (B, C, and D), while pigs on treatment E were reared outdoors in Kikuyu grass paddocks. There was a significant correlation between the amount of concentrate offered and its intake (P??0.05). Mean acid-insoluble ash digestibility estimates of organic and dry matter were superior to C(32) estimates (P?相似文献   

4.
Domestic herbivores’ effect on vegetation is spatially heterogeneous, being one of the major causes of forage resources degradation. It has been proposed that paddock size controls grazing impact’s heterogeneity because as size decreases, herbivores’ utilization is spatially more even. However, this has not been critically evaluated in commercial-scale paddocks isolating paddock size effects from other factors influencing the interaction between herbivores and vegetation. Here we assessed how paddock size mediates the heterogeneity of continuous sheep grazing effects on vegetation, at constant stocking rate in Patagonian steppes. We selected three small (ca. 110 ha) and three large (ca. 1 100 ha) paddocks dominated by the same plant community. All paddocks contained a single watering point and presented similar shape. Total and specific plant cover, vegetation patchiness, population size distribution of dominant grass species, plant morphology, and sheep feces density were estimated at increasing distances from watering points. Relationships between vegetation variables and distance from the watering point were in most cases asymptotic exponential, although responses generally differed between small and large paddocks. In small paddocks, vegetation variables mostly reached a plateau at a short distance from the watering point (~ 200 m). Instead, in large paddocks, the changes in vegetation variables were larger and more gradual, and reached a plateau at much greater distances (~ 2 000 m). Vegetation heterogeneity throughout the paddock was lower in small than large paddocks. Our findings suggest that paddock size mediates the spatial pattern of grazing effects on vegetation. Reducing paddock size decreases grazing impacts spatial heterogeneity, which makes plant-animal interactions more predictable and might improve forage utilization efficiency.  相似文献   

5.
Three experiments using 63 Thoroughbred and Quarter Horse yearlings were conducted to evaluate the influence of level of feeding, and protein and calculated energy content of pelleted concentrates on growth and bone development. Animals were housed in drylot paddocks and individually fed concentrates twice daily. Coastal bermudagrass (Cynodon dyctylon) hay was group-fed. Yearlings offered a corn-based concentrate (3.56 Mcal digestible energy [DE]/kg) consumed levels of dry matter similar to yearlings fed a mixed-grain concentrate (3.32 Mcal DE/kg but consumed slightly more digestible energy. No differences in growth or bone development were detected. Yearlings fed restricted levels of concentrate that provided approximate National Research Council (NRC) recommendations for protein and DE had lower weight and girth gains (P less than .05) than those provided ad libitum concentrate intake during two 1.5-h daily feeding periods. Restricting concentrate intake had no effect on skeletal growth (P less than .05) but resulted in numerically lower values for bone radiographic density. Protein addition to a diet restricted to approximate NRC energy intake recommendations had no effect on weight gain, body measurements or bone mineral deposition (P greater than .05) and growth and development was less than that resulting from higher intakes of a lower protein concentrate.  相似文献   

6.
Foraging behaviour and daily weight gain (DWG) were studied in outdoor pigs given 100 or 80% of the indoor recommended feed allowance. In total, there were four groups of pigs, two per treatment. Each group consisted of 11 growing pigs with an initial live weight (LW) of 50.3 kg. The pigs foraged on a clover/grass pasture for 6 weeks in the cropping season. Behaviour was recorded within three zones of the experimental area: newly allotted area, transfer area and dwelling area. Mean DWG was 811 and 686 g on the 100 and 80% levels, respectively. The feed conversion ratio did not differ between treatments. A higher frequency of rooting and a lower frequency of behaviours categorised as other activities were observed on the 80% level than on the 100% level. Grazing and rooting were more frequent on newly allotted areas compared with the transfer and dwelling areas, whereas passive behaviour and other activities were more frequent in the transfer area. Defecation and urination were most frequent in newly allotted areas, followed by the dwelling area. The results suggest that successive allocation of new land gives rise to a distinct foraging area, which also is frequently used for excretory behaviour. Reducing feed allowance by 20% increased the nutrient intake from the herbage by ∼5%.  相似文献   

7.
Forty-four Thoroughbred and Quarter Horse weanlings were used in three experiments to evaluate the effects of energy content, protein content, and feeding levels of the concentrate on growth and development when fed with Coastal bermudagrass hay. The animals were confined to drylot paddocks and fed the assigned concentrate in individual feeding stalls. The hay was group-fed in the paddocks. In the first experiment, the concentrate was fed at 1.5 kg/100 kg BW daily or ad libitum for two 1.5-h feeding periods daily. The ad libitum-fed weanlings had greater withers height gain (P<0.01), and hip height gain (P<0.05) than the limit-fed weanlings. Bone mineral gains were numerically greater for the ad libitum-fed weanlings (P>0.10). None of the other body measurements were different (P>0.05). In Exp. 2, weanlings were fed a basal concentrate ad libitum for two1.5-h feeding periods daily or a fat-added concentrate at equal amounts to the hay intake. Nutrients were balanced to meet NRC recommendations. The fat-added concentrate resulted in numerically greater withers height (P>0.10), heart girth (P>0.10), body length (P>0.10), hip height (P>0.10), and bone mineral (P>0.10) gains. Weight gain and feed efficiency favored the basal diet. In Exp. 3, weanlings were fed concentrates providing either 14 or 18% CP as described previously. The BW gains favored the high protein diets for three of the first four periods (P<0.05), and some numerical advantage persisted to the end of the trial (P>0.10). None of the other growth measurements were different for the two diets. Calculations on nutrient intake and BW gains of the animals on the three experiments revealed that lysine intake appears to be a greater factor than energy or protein in influencing BW gain of weanlings.  相似文献   

8.
ABSTRACT

This study investigated how intensively manipulated grass/clover silage (finer structure than chopped silage) fed in total mixed ration (TMR), influenced feed consumption, total tract apparent digestibility (TTAD) and pig behaviour. Ten Yorkshire x Hampshire (YH) pigs were included in a digestibility experiment and 64 YH pigs in a behaviour experiment. Pigs received TMR with 20% dry matter inclusion of either intensively manipulated (SI) or chopped silage (SC). Behaviour was registered with instantaneous and continuous sampling. SI pigs consumed more silage (p?=?0.001) and spent more time eating from the through (p?<?0.01), however no significant difference in TTAD was found (p?>?0.05). Less social interactions prior to feeding (p?=?0.029) and less rooting after feeding (p?<?0.05) were found among SI pigs, indicating SI pigs being more satisfied for a longer time after feeding. We conclude that TMR with intensively manipulated silage benefits feed consumption and increases the opportunities for pigs perform feed-related behaviours.  相似文献   

9.
Abstract

During two different years, 1986 and 1989, 129 and 102 ewes, respectively, were used to compare the effects of level and feeding pattern of concentrate during the last eight weeks of pregnancy. The ewes were given hay to cover maintenance, with supplemental feeding for pregnancy based on different amounts of concentrate. The control groups were fed according to Swedish recommendations, totalling 20 kg of concentrate, maximum level 0.4 kg per ewe and day (20:0.4) in a two-level pattern. The experimental groups were fed 20:0.7, 24:07 or 30:1.0 with a gradually rising feeding pattern. The treatments had a significant effect on changes in the live weight of ewes during late pregnancy and early lactation, with ewes on higher feeding levels losing less weight during pregnancy and gaining less weight on pasture. Over the whole production year, the changes during different production periods levelled out the total effect. Late pregnancy feeding also had a significant effect on lamb growth, with lambs from ewes fed on the highest feeding level growing significantly better. Lambs from ewes fed on a gradually rising feeding pattern showed significantly better growth in Expt. 1 but not in Expt. 2.  相似文献   

10.
The effects of the β2-agonist salbutamol, on pig heart rate and blood pressure were evaluated at the expected commercially used concentration of 3 ppm in final feed, and at three times this level. Salbutamol was administered to pigs previously fed on control diet (‘naive’), and in a second study to pigs fed 3 ppm salbutamol for 19 days (‘acclimatized’). Heart rate and blood pressure were measured in conscious 30 kg pigs before (pre-ingestive), during (ingestive) and after ingestion (absorptive) of feed containing 3 or 9 ppm salbutamol. To assess any interaction with ‘stress genotype’ pigs, measurements were performed in Large White and Pietrain-cross breeds. The mean preingestive heart rates for the Large White and Pietrain-cross pigs were 127 and 109 beats/min, respectively. The corresponding figures for mean arterial blood pressure were 121 and 122 mmHg. The act of ingesting control feed caused heart rate to rise by 36–39% and blood pressure to increase by 17–27%. During the absorptive phase for ‘naive’ pigs fed 3 ppm salbutamol in the diet, blood pressure fell 5–11% and heart rate increased 20–24%, reflecting a classical baroreceptor mediated response. At 9 ppm the fall in blood pressure of 5–11% was similar to that at 3 ppm, while the rise in heart rate was larger at 31–38%. The magnitude of the changes at both 3 and 9 ppm was less than that evoked by the act of ingestion, with the exception of the heart rate response in Large Whites at 9 ppm, which was similar. The responses of the two breeds were comparable, indicating that salbutamol is unlikely to exacerbate the cardiovascular responses seen in potentially stress-susceptible pigs. The acute changes elicited by 3 ppm salbutamol during the absorptive phase in ‘naive’ pigs were abolished or substantially less in acclimatized pigs, implying a tachyphylaxis to the agonist's actions. This was confirmed by 9 ppm of salbutamol increasing heart rate of ‘acclimatized’ Large Whites to the same degree as 3 ppm in ‘naive’ counterparts. The desensitization in Pietrain-cross pigs was even more marked with no increase in heart rate produced by 9 ppm salbutamol following acclimatization. These data, combined with the rapid tachyphylaxis of response, indicate that salbutamol at the intended commercial inclusion of 3 ppm will not compromise the cardiovascular stability of the growing pig at rest.  相似文献   

11.
Abstract

The aim of the study was to investigate the feeding behaviour differences between Kr?kopolje pig (KP) and a modern hybrid (MH) pig. The behaviour was recorded during concentrate and hay consumption after the body weight of pigs was 100 kg. Animals (N=24) were observed in a straw-bedded system in eight pens of three pigs. During concentrate consumption, feeding, drinking and displacement at the trough (when a pig changed a feeding place) were directly recorded. During hay consumption, hay chewing, resting, exploring, playing and synchronisation while hay chewing were scored. MH ate faster and drank less than KP; however, they changed their feeding places more often and showed a higher probability to chew hay (overall P<0.01). MH pigs tended to chew hay more synchronously than KP (P<0.10). The results show that concentrate and hay consumption habits vary between the Slovene KP and the MH pig.  相似文献   

12.
Seventeen Thoroughbred and Quarter Horse yearlings were used in a 2×2 factorial experiment to determine 1) whether adding fat (5% corn oil) to the concentrate would influence feed intake, growth and development and 2) whether time of hay feeding would influence energy metabolism on the basal and added fat diets. Yearlings were assigned at random, within breed and gender subgroups, to one of four diets: B-I, basal concentrate with Coastal Bermuda grass (Cynodon dactylon) hay fed immediately after the concentrate; B-D, basal with hay fed 3.5 hr after the concentrate; F-I, basal + fat with the hay fed immediately; and F-D, basal + fat with the hay fed 3.5 hr after the concentrate. The basal concentrate was formulated to meet or exceed NRC (1989) recommendations when fed with the hay. The basal + fat concentrate was formulated at 9.7% higher digestible energy than the basal concentrate and all of the other nutrients were increased proportionately so if the intake was reduced, the yearlings would still meet nutrient needs. The concentrates were fed individually to appetite for two 1.5-hr feeding periods daily in 1.5×3.0 m slip stalls. Hay was group fed in the paddocks at a rate of 1.0 kg/100 kg BW daily divided into two equal feedings. Animals were housed in four 9.1×34.9-m drylot paddocks with three, four, or five animals in each paddock. The mean age at the start of the experiment was 377±8 days. Weight and body measurements for withers height, heart girth, body length, and hip height were taken at the start of the experiment and at 28-day intervals for 84 days. Radiographs for bone mineral estimates were made at the start and completion of the experiment. During the final 28-day period of the feeding trial, three animals from each experimental group were randomly selected for a 24-h period of blood sampling to evaluate the effects of the diets on blood glucose and insulin.Fat addition to the concentrate reduced the daily concentrate DM (P=0.0187) and total feed DM (P=0.0021) intake. When feed intake was expressed as a function of BW, concentrate and total feed intakes were 1.33 and 2.14 kg/100 kg BW daily and were not influenced by diet (P>0.1). Colts consumed more concentrate DM (P=0.0039) and total feed DM (P=0.0022) than fillies. The yearlings gained an average of 0.60 kg/d for the 84 days. Weight gain, body measurements and bone mineral deposition were not influenced by gender or diet. Mean plasma glucose concentrations were higher (P=0.05) in yearlings consuming the basal concentrate with hay fed immediately than when hay feeding was delayed. When fat was fed, the time of hay feeding had no effect on plasma glucose concentrations (P>0.05). Plasma glucose and insulin were lowest just prior to the morning feeding and peaked two to three hours after both morning and afternoon feedings. Fat supplementation reduced plasma insulin (P=0.001). Results suggest that the addition of 5% corn oil to a yearling concentrate may reduce feed intake but will not reduce growth and development of the animal if other nutrients are supplied at concentrations that provide for the animal's daily needs. Delaying hay feeding may be advantageous to growing horses as it may allow the concentrate to move down the tract at a slower rate reducing the glucose peaks.  相似文献   

13.

The effect of feeding environment on individual pigs (small, medium and large barrows) housed in groups of 16 pigs was studied. The experiment comprised the following four treatments: trough feeding, four dry feeders, one dry feeder and one wet/dry feeder per 16 pigs, respectively. Performance, skin injuries, plasma cortisol, agonistic behaviour, ingestive behaviour and activity were studied. The effect of competition for feed was most clearly evident for the small pigs. The small animals in the one dry feeder treatment were forced to eat more during the night, had more forced withdrawals from the feeder, and tended to have more scratches and skin injuries than did the small animals in the four dry feeder treatment. It was concluded that this competition led to impaired well-being in the smallest pigs. No significant differences were detected in plasma cortisol levels, when comparing the different feeding systems within each pig size category. Trough feeding greatly affected pig feed intake pattern: during the growing period when pigs had ad libitum access to feed, the pigs fed in a trough ate mostly at feeding times, while the pigs in the four dry feeder treatment ate at times spread out over the entire 24 h period. It was concluded that there was a confounding effect between pig size category (small or large) and feeding system with regard to ingestive behaviour and aggressive interactions at feeding.  相似文献   

14.
Abstract

The effects of two housing systems (deep litter and straw-flow), with and without access to pasture during the summer period, were studied in an organic growing-finishing pig herd. Performance, health, skin lesions and daytime pig activity were studied in 29 pens of 16 pigs (total of 464 pigs, in 4 batches). Data from 21 pens were used for comparisons of deep litter and straw-flow and data from 16 pens for comparisons of access/no access to pasture. Pigs in the deep litter system had a lower carcass meat percentage (56.6% vs. 57.3%) and more locomotion problems (4.4% vs. 0%) than pigs in the straw-flow system. No difference in daytime pig activity was detected between the two housing systems. Under moderate temperatures, pigs with access to pasture and fed a commercial organic feed inside the building were not more active during daytime behaviour studies (7.30?h–16.30?h) than pigs without access to pasture. However, at 17 weeks of age the pigs with pasture access spent 21% of their time on pasture, less time inside the pig house (20% vs. 33%) and less time on the outside concrete area (4% vs. 12%) than the pigs without pasture. No difference in performance was detected between pigs with and pigs without access to pasture.  相似文献   

15.
The study was conducted to determine the effects of feeding a 16% CP diet, a 12% CP diet, or a 12% CP diet supplemented with crystalline Lys, Trp, and Thr (12% CP + AA diet) in a thermal-neutral (23 degrees C) or heat-stressed (33 degrees C) environment on various body and physiological measurements in growing pigs. Heat-stressed pigs were given a 15% lower daily feed allowance than thermal-neutral pigs to remove the confounding effect of feed intake caused by high temperature. No diet x temperature interaction was observed for any variables (P > 0.09) except for pig activity and pancreas weight. At 33 degrees C, pig activity and pancreas weight did not differ among dietary treatments (P > 0.05). In contrast, at 23 degrees C, pigs fed the 12% CP diet had greater activity than those fed the 16% CP diet or the 12% CP + AA diet (P < 0.05). Pancreas weight was greater for pigs fed the 12% CP + AA diet than those fed the 12% CP diet (P < 0.05) when maintained at 23 degrees C. Compared with 23 degrees C, the 33 degrees C temperature decreased pig activity, heat production, daily gain, feed efficiency, and affected the concentration and accretion of empty body protein and ash, as well as weights of heart, pancreas, stomach, and large intestine (P < 0.05). Pigs fed the 12% CP + AA diet attained similar levels of performance and rates of empty body water, protein, lipid, and ash deposition as pigs fed the 16% CP diet (P > 0.10). Pigs fed the 12% CP + AA diet had lower serum urea plus ammonia nitrogen concentrations (P < 0.01) and total heat production (P < 0.05) compared with those fed the 16% CP diet or the 12% CP diet. These results confirm that, with crystalline AA supplementation, growing pigs fed a 12% CP diet will perform similar to pigs fed a 16% CP diet. The data further indicate that lowering dietary CP and supplementing crystalline AA will decrease total heat production in growing pigs whether they are housed in a thermal-neutral or heat-stressed environment.  相似文献   

16.
We have previously demonstrated that recurrent application of glyphosate causes dramatic shift in the vegetation structure of the native grasslands of Flooding Pampa. As these structural changes might alter functional processes such as primary production, carbon, nitrogen and phosphorus cycling, this study aims to evaluate functional changes associated with the application of glyphosate in these temperate grasslands. We measured aboveground net primary production (ANPP) during two consecutive years, and the concentration of organic carbon, nitrogen and phosphorus in the soil during the following six years after primary production measurements ended in glyphosate treated and non- treated (control) paddocks of a commercial livestock far. We related the vegetation data, basal cover, species richness and diversity, obtained in a previous study conducted in the same paddocks of the livestock farm, with ANPP data obtained in this one. Late summer applications of glyphosate greatly reduced the biomass contribution of warm-season perennial grasses and legumes and increased the contribution of cool season annual grasses, altering the seasonal pattern of ANPP. As the reduction of the spring and summer productivity could not be compensated by the increase of cool-season productivity, the annual ANPP was lower in the glyphosate-treated paddocks than in control paddocks. Glyphosate applications also decreased soil organic carbon and phosphorus concentration, probably because of the reduction of ANPP, the changes of its seasonal distribution and the shift in the floristic composition of the community, which may modify the amount and quality of the litter. We found a linear positive relationship between basal cover, species richness and species diversity with ANPP, which suggest that the negative effects on ecosystem functioning would be directly related with the changes in vegetation structure caused by glyphosate application.  相似文献   

17.
The objective of this growth trial was to determine the interrelationship between immunological criteria, gut morphology, and performance of starter pigs fed soybean proteins processed by different methods. One hundred twenty-five pigs were orally infused with 6 g/d of either dried skim milk, soybean meal (48% CP), soy protein concentrate, extruded soy protein concentrate, or experimental soy protein concentrate from 7 to 11 d of age and then fed a diet containing the same protein sources from weaning (d 21) to 35 d of age. All pigs were fed a corn-soybean meal diet containing 10% dried whey, 1.25% lysine, and 3% soybean oil for the remaining 21 d of the experiment. Xylose absorption and anti-soy immunoglobulin G (IgG) titers were measured on d 6 postweaning, and skin-fold thickness after intradermal injection of protein extracts was measured on d 7 postweaning. A total of 25 pigs (five pigs/treatment) was euthanatized on d 7 postweaning. Villus height and crypt depth from duodenum samples were measured. These measurements were obtained to elucidate a relationship between the hypersensitivity responses to soybean products and growth performance of baby pigs. Pigs fed diets containing soybean meal had a lower (P less than .05) rate of gain (d 0 to 14) and villus height, higher (P less than .01) serum anti-soy IgG titers, and increased skin-fold thickness (d 6 and 7 postweaning) after intradermal injection compared with those fed dried skim milk. Pigs fed other soy proteins also had lower ADG from d 0 to 14 postweaning; however, pigs fed moist extruded soy protein concentrate tended (P less than .09) to have higher ADG and improved feed utilization when compared with pigs fed soybean meal (d 0 to 14).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

18.
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.  相似文献   

19.
Forty-eight barrows were used in a 2 x 6 factorial arrangement to test a hypothesis that feeding a protein-deficient diet affects subsequent growth response by altering the efficiency of protein utilization. Barrows were individually fed either a 9% crude protein (CP) diet or an 18% CP diet from 20 to 30 kg of body weight (BW) (depletion phase). From 30 to 45 kg BW (realimentation phase), pigs were fed one of six experimental diets with CP levels of 11.8, 13.1, 14.3, 15.6, 18.8, and 21.8%. Four pigs were slaughtered at 20 kg BW to determine initial body composition. Four pigs from each treatment in depletion phase (a total of eight) were slaughtered at 30 kg BW, and all pigs from each treatment in realimentation phase (a total of 36) were slaughtered at 45 kg BW for subsequent compositional analysis. Pigs were bled at 20, 30, and 40 kg BW for blood urea nitrogen (BUN), insulin-like growth factor (IGF)-I, and IGF-binding protein (IGFBP) assays. Pigs were given three times the maintenance digestible energy requirement (3 x 120 kcal BW(-0.75) x d(-1)) in three equal meals daily. The feed allowance was adjusted every 3 d. During the depletion phase, pigs fed the 18% CP diet grew faster and more efficiently (P < 0.01) and gained more (P < 0.01) water and protein than did pigs fed the 9% CP diet. Pigs fed the 18% CP diet showed higher (P < 0.01) BUN values, IGF-I concentrations, and IGFBP ratios than pigs fed the 9% CP diet. During the realimentation phase, pigs fed the 9% CP diet during the depletion phase grew faster (P < 0.05), tended to grow more efficiently (P = 0.066), gained more water (P < 0.01), and tended to gain more protein (P = 0.068) than pigs fed the 18% CP diet during the depletion phase. Pigs fed the 9% CP diet during the depletion phase tended (P = 0.069) to have a higher protein requirement during the realimentation phase than pigs fed the 18% CP diet during the depletion phase. When measured at 40 kg BW, pigs fed the 9% CP diet had a lower (P < 0.05) BUN than pigs fed the 18% CP diet during the depletion phase. However, the plasma IGF-I concentration and IGFBP ratio at 40 kg BW were not affected by dietary CP level fed during the depletion phase. This study indicates that pigs fed a protein-deficient diet exhibit compensatory growth. During the period of compensatory growth, the requirement of CP for those pigs is higher than that of pigs previously fed an adequate diet. This study also suggests BUN can be used as an indicator of protein utilization efficiency and compensatory growth.  相似文献   

20.
The objective of this experiment was to study the effects of feeding group-housed gestating sows a diet with a high level of fermentable nonstarch polysaccharides (NSP; approximately 45% sugar beet pulp as fed) ad libitum on the development in individual feed intake characteristics and reproductive performance during three successive reproduction cycles. Performance of the ad libitum-fed sows was compared to the performance of sows that were fed a conventional diet restrictedly. Feed intake characteristics during gestation were only measured in the ad libitum-fed sows. One hundred and nineteen sows were assigned to one of two gestation feeding regimens. Gestating sows were fed a conventional Dutch diet restrictedly or a diet with a high level of fermentable NSP ad libitum. During lactation, sows were given free access to a commercial lactation diet from d 6 after parturition onward. The ad libitum-fed sows ate 1.3 kg/d more during gestation than the restrictedly fed sows (P < 0.001), resulting in higher body weight and backfat gains during gestation (P < 0.05). Sows that were fed ad libitum during gestation lost more body weight and backfat during lactation (P < 0.001) than sows that were fed restrictedly during gestation. Feed intake during lactation, however, did not differ between sows that were fed restrictedly or ad libitum during gestation. The numbers of total piglets born, live-born and stillborn piglets, piglet birth weight, weaning-to-estrus interval, and percentage of sows that returned to estrus after first insemination were not affected by gestation feeding regimen. Mean daily voluntary feed intake (as-fed basis) over the three reproduction cycles in the ad libitum-fed gestating sows was 4.2 kg/d. Depending on the number of preceding reproduction cycles during which a sow was fed ad libitum, the maximum voluntary feed intake was reached in Parity 3, 4, or 5 and then remained stable in subsequent parities. Mean daily feed intake of the ad libitum-fed sows increased from wk 2 to 6 of gestation and then decreased to wk 15 of gestation. The mean number of daily visits with feed intake over the three reproduction cycles was 13.8. On average, ad libitum-fed sows spent 90 min/d on eating. This study shows that it is possible to feed gestating sows a diet with a high level of fermentable NSP ad libitum during three successive reproduction cycles without negative effects on reproductive performance.  相似文献   

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