Effect of evening or morning weaning and immediate or delayed feeding on postweaning performance of pigs.

Weanling pigs (n = 176), 21 to 26 d of age (average initial weight, 7.1 kg), were used to evaluate the effects of weaning time (evening vs morning) and feeding time (immediate vs delayed) on postweaning performance. Pigs were randomly allotted within litters to four treatments in a 2 x 2 factorial arrangement as follows: 1) weaning at 2000 with immediate feeding, 2) weaning at 2000 with 12-h delayed feeding, 3) weaning at 0800 with immediate feeding, and 4) weaning at 0800 with 12-h delayed feeding. A 12:12 light:dark photoperiod was maintained. Four pigs were held per pen, and all pigs were given ad libitum access to a 20% CP corn-soybean meal diet with 15% dried whey throughout the 28-d study. The interactions between weaning and feeding times were not significant. During the 28-d period, pigs weaned at 2000 consumed 5% more feed (P less than .10) and grew 6% faster (P less than .05) than pigs weaned at 0800. Feed to gain ratios were similar for both time treatments. Variance of ADG within pens as measured by range, logarithm of variance, and CV were generally smaller for pigs weaned at 2000 than for pigs weaned at 0800 with no effect of feeding time. Pigs fed immediately after weaning and those delayed for 12 h had similar overall feed consumption, ADG, and feed to gain ratios. Weaning pigs in the evening enhanced performance, perhaps by better matching the normal diurnal eating and activity patterns and weaning time.     

Influence of increased feeding frequency on behavior and integument lesions in growing-finishing restricted-fed pigs

This study evaluated how feeding frequency affects behavior and the occurrence of skin lesions in growing-finishing pigs. One hundred eighty pigs (27 to 112 kg of BW) were reared in one environmentally controlled room (20 pens; 9 pigs/pen). Pigs in 10 pens were fed 3 times daily (reference group), whereas the others were fed 9 times daily (experimental group). Both groups received the same total amount of liquid feed. Rations were adjusted to the mean pen weights. Behavioral observations (scan sampling, as well as continuous focal pig observations) were made in wk 4, 10, and 14 of the growing-finishing period. After each observation, skin lesions were assessed individually for each pig. Pigs fed 9 times daily tended to lie laterally for less time (P = 0.083) and tended to be active (P = 0.054) during the day, especially in growing-finishing wk 4 (P = 0.007). With continuously observed focal pigs, no differences in time allocations for feeding were found between groups. During feeding in growing-finishing wk 4, focal pigs belonging to the experimental group displayed more aggressive actions (P = 0.019), tended to perform aggressive actions for a longer time (P = 0.076), and tended to be belly-nosed for a longer time (P = 0.083) compared with the reference group. In addition, in growing-finishing wk 14, pigs in the experimental group had greater scores for skin lesions (head, P = 0.001; belly, P < 0.001; caudal part, P < 0.001) and tended to be belly-nosed for a longer time (P = 0.084). In the case of pigs restricted-fed liquid feed, a greater frequency of feeding per day appears to be a condition that results in greater competitive feeding than with a lower feeding frequency.     

Weekly digestibilities of diets supplemented with corn oil, lard or tallow by weanling swine

Two experiments were conducted to evaluate supplementation of diets with 8% corn oil, lard or tallow. In Exp. 1, 36 barrows weaned at 21 d of age were used to evaluate the effects of these three diets on digestibilities of fat and dry matter and subsequent N retentions from wk 1 to 4 postweaning. In Exp. 2, 147 weanling pigs in six replicates were used to evaluate weekly growth and feed performance measurements when fed these same diets for a 4-wk postweaning period. A large quantity of fat was absorbed (P less than .01) during wk 1 postweaning by pigs fed the corn oil diet, with the quantity absorbed similar for the three sources of fat from wk 2 to 4. Diets with corn oil had a higher apparent fat digestibility than diets supplemented with lard or tallow during each week postweaning (P less than .05). Apparent digestibility of fat increased (P less than .01) for each fat source each week postweaning but appeared to reach a plateau by wk 3 postweaning. Differences in apparent digestibility of fat between fat sources narrowed from wk 1 to wk 4, with digestibility of corn oil increasing from 79 to 89% and of animal fat sources increasing from 67 to 84%. Apparent digestibility of dry matter tended (P less than .10) to be highest when corn oil was provided during the initial 2-wk postweaning period. Although N retention was highest during wk 1 postweaning when the corn oil was fed, this response was attributed to the higher feed intakes of pigs fed this diet.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of feed intake fluctuation and frequency of feeding on nutrient digestion, digesta kinetics, and ruminal fermentation profiles in limit-fed steers

Nine crossbred beef steers (344 +/- 26 kg) fitted with ruminal cannulas were used in a randomized complete block design to evaluate the effects of feeding frequency and feed intake fluctuation on total tract digestion, digesta kinetics, and ruminal fermentation profiles in limit-fed steers. In Period 1, steers were allotted randomly to one of four dietary treatments: 1) feed offered once daily at 0800; 2) feed offered once daily at 0800 with a 10% fluctuation in day-to-day feed intake; 3) feed offered twice daily at 0800 and 1700; and 4) feed offered twice daily at 0800 and 1700 with a 10% fluctuation in a day-to-day feed intake. In Period 2, steers were reallocated across treatments. The 90% concentrate diet was fed at 90% of the ad-libitum consumption by each steer. Chromium-EDTA and Yb-labeled steam-flaked corn were intraruminally infused at 0800 on d 1 and 3 and Co-EDTA and Er-labeled steam-flaked corn were infused on d 2 and 4 of the 4-d collection period. Ruminal samples were collected at 0, 3, 6, 9, 12, 15, 18, and 24 h after the 0800 feeding, and total feces were collected for 4 d. Total tract digestibilities of OM, N, and starch were lowest (fluctuation x frequency, P < .05) when feed was offered twice daily with a 10% fluctuation in intake. Ruminal fluid volume and passage rate were not affected (P > .10) by feeding frequency or intake fluctuation. A frequency x fluctuation x sampling time interaction occurred (P < .01) for ruminal pH. Steers fed a constant amount of feed once daily had higher (P < .05) ruminal pH at 0, 3, 18, and 24 h than steers fed once daily with a 10% fluctuation in feed intake. Total VFA concentration was greater (P < .01) at 9 h after the 0800 feeding when feed was offered once vs twice daily. Feeding twice daily increased (P < .05) the molar proportion of acetate and decreased (P < .05) the molar proportion of propionate. Increasing feeding frequency resulted in a more stable ruminal environment; however, the increased acetate:propionate ratio with twice-daily feeding might result in lower efficiency of energy utilization by limit-fed steers.     

Effect of inorganic selenium supplementation on selenosis in postweaning swine

A total of 72 pigs weaned at 4 wk of age were allotted by litter and weight to nine treatment groups and fed 20% protein cornsoybean meal diets supplemented with various levels of inorganic Se during a 37-d postweaning period. Eight groups were fed diets with 0, 2.5, 5.0, 7.5, 10, 15, 20 or 40 ppm Se provided as sodium selenite, while a ninth was offered the 0- and 40-ppm Se diets in separate feeders. Gains and feed intakes were similar during the trial for the 0- and 2.5-ppm Se diets. Both gain and feed intake declined as dietary Se levels above 5.0 ppm increased. At a dietary Se concentration of 40 ppm, feed consumption ceased within a few days of feeding and subsequent gains were negative. Pigs offered both the 0- and 40-ppm Se diets preferentially selected the basal as compared with the 40-ppm Se diet. When the feeders were switched at 28 d they refused the 40-ppm Se diet within a few hours. After a 17-d period, pigs fed the 20- or 40-ppm Se diet were not able to coordinate their walk, with many exhibiting an inability to stand. Alopecia was demonstrated in pigs fed 15 ppm Se or higher at 17 d, but was evident in the 5.0-ppm group at 37 d. At the termination of the trial, abnormal hoof formation at the coronary band was evident in pigs fed diets containing Se greater than or equal to 5 ppm.(ABSTRACT TRUNCATED AT 250 WORDS)     

Feeder location did not affect performance of weanling pigs in large groups

Crossbred pigs weaned at 17 d of age (n = 1,760; mean initial BW = 5.6 +/- 0.7 kg) were used in two 4-wk trials (four replicates per trial) to evaluate the effects of three pen designs on pig performance. The designs were 1) large group size (100 pigs/pen) with five two-sided feeders in a single, central location in the pen; 2) large group size (100 pigs/pen) with five two-sided feeders in multiple (five) locations in the pen; and 3) small group size (20 pigs/pen) with a single two-sided feeder in a central location in the pen. Each feeder provided two 20.3-cm-wide feeding places on each side. Pigs had free access to feed and water. Feeder-trough space (4 cm/pig) and floor-area allowance (0.17 m2/pig) were the same for all treatments. Pigs in the large-group treatments were lighter (15.6 and 15.6 vs 16.0 kg; P < 0.01) at the end of wk 4 and had lower ADG (358 and 357 vs 373 g; P < 0.01) and ADFI (510 and 521 vs 544 g; P < 0.01) during wk 2 through 4 than pigs in small groups. Gain:feed ratio was similar (P > 0.05) for all treatment groups throughout the study. For large groups, feed disappearance from each of the five feeders was similar (P > 0.05) for both multiple- and single-location treatments. In summary, large group size reduced pig growth performance, but the approach to providing multiple feeding locations that was employed in this experiment did not increase feed intake or growth performance of pigs in the large groups.     

Effects of continual fluctuation in feed intake on growth performance response and carcass fat-to-lean ratio in grower-finisher pigs

An experiment was conducted to examine the effect of continual fluctuations in feed intake on grower-finisher pig growth performance and carcass fat-to-lean ratio (F:L). Sixty individually housed female pigs (Landrace x Large White) with initial BW of 29.8 +/- 0.4 kg were randomly allocated to 1 of 4 feeding regimens (n = 15): 1) ad libitum throughout (AL); 2) 85% of the mean intake of the AL group during the previous week (R); 3) 70% of the mean intake on 1 d, and on the following day, 100% of the amount consumed by the AL group during the preceding week, with this pattern repeated every 2 d throughout (D); and 4) 70% of the mean intake for 3 consecutive days, and 100% of the amount consumed by the AL group for the next 3 d, with this pattern repeated throughout the experiment (3-D). Pigs receiving each treatment were fed the same diets during the weaner (10 to 20 kg), grower (20 to 50 kg), finisher 1 (50 to 70 kg), and finisher 2 (70 kg to slaughter at approximately 104 kg) growth phases. Pigs receiving fluctuated feed intake either by the D or 3-D feeding regimen showed a pattern of growth similar to that of pigs on the R feeding regimen. Pigs on the R and 3-D regimens were lighter at 28 d (P < 0.05) and pigs on the R, D, and 3-D regimens were lighter at 63 d (P < 0.05) than pigs on the AL regimen. Pigs on the R, D, or 3-D feeding regimens had a greater G:F between 15 to 42 d of the experiment than pigs fed AL throughout (P < 0.05). The R, D, and 3-D feeding regimens seemed to have some effect on carcass weight and dressing percentage, and pigs had a decreased P2 (located 65 mm from the midline of the carcass at the last thoracic rib) backfat depth (P < 0.05) compared with pigs fed AL. Pigs on the AL and 3-D feeding regimens had thicker subcutaneous fat at the last lumbar vertebrae on the dorsal edge of the loin than pigs on the R feeding regimen (P < 0.05). Carcass and visceral fat content and the F:L in the carcass and primal cuts, as measured by dual energy x-ray absorptiometry, were not different among treatments. However, pigs on the AL and 3-D feeding regimens had decreased estimated bone content in the carcass compared with pigs on the R and D feeding regimens (P < 0.05). The results indicated that continual fluctuation in feed intake either every other day or every 3 d had minimal effects on growth and carcass F:L compared with pigs fed the same restricted amount throughout the experiment.     

补偿性生长养猪粪便减排效果试验报告

为从"源头控制"畜禽粪便减排,提高生猪养殖效益,本试验将同日龄、初始体重相近的(P＞0.05)育肥猪40头分成4个组,1个对照组(正常饲喂)和3个试验组,每组10头,试验组分限饲10％组、限饲20％组、限饲30％组.试验组限饲50 d后,解除限制饲喂30 d,在管理条件基本相同情况下发现限饲期间,试验各组猪的粪便产生量...     

Effect of split marketing on the welfare, performance, and carcass traits of finishing pigs

The aim of this study was to compare a split marketing (SM) strategy, in which the heaviest pigs in a group are removed and slaughtered earlier than the others, with an all-out (AO) marketing strategy, in which all pigs are removed from the pen simultaneously and slaughtered on the same day, in terms of welfare, performance, and carcass traits of noncastrated (i.e., intact) male and female pigs. The experimental treatments were arranged in a 2 × 2 factorial array with 1) marketing strategy (SM vs. AO) and 2) sex (males vs. females), which yielded 4 treatment groups of 14 pigs (73.1 ± 4.8 kg): male SM, male AO, female SM, and female AO (7 replicates/group). Pigs in AO groups were all slaughtered after 6 wk on trial, whereas in SM groups the 3 heaviest pigs were removed and slaughtered 2 wk before the remainder of the group, which were slaughtered at the same time as the AO pigs. Pigs were fed a liquid diet from a long trough 3 times daily. Behavioral observations were conducted before and after SM, the day of SM, and 1 and 2 wk later. Behavior was recorded both during and between feed events, and skin lesions were scored on all, except the 3 pigs removed from SM groups before and 2 wk after SM. Growth performance, feed efficiency, and carcass traits were recorded. The number of aggressive interactions during feed events decreased after the 3 pigs were removed from SM groups. This reduction in aggressive interactions was observed on the day of SM in male groups (before SM: 24.3 vs. the day of SM: 14.7, SED = 3.31, P < 0.05 for interaction) and in subsequent observations in female groups (before SM: 21.4 vs. days after SM: 13.4, SED = 3.31, P < 0.05 for interaction). However, SM had no effect on behaviors recorded between feed events or on the number and severity of skin lesions (P > 0.10). There were no differences between the 11 remaining pigs in SM groups and the 14 pigs in AO groups in terms of growth performance, feed efficiency, and carcass traits of female or intact male pigs (P > 0.10). However, reduced within-pen CV in carcass weight was detected in pigs from SM groups compared with pigs from AO groups (8.6 vs. 10.9, SEM = 0.72, P < 0.05). Therefore, in restrictively fed pigs, a SM strategy improved the welfare of both female and intact male pigs by reducing aggressive interactions during feeding but had no effect on performance or carcass traits.     

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 a parenteral supplement of folic acid and its interaction with level of feed intake on hepatic tissues and growth performance of young dairy heifers.

Forty-seven dairy heifers of approximately 10 d of age were assigned to a factorial experiment in which a supplement of folic acid (0 or 40 mg) administered weekly by i.m. injection and level of feed intake were the two factors studied. The heifers were weaned after 5 wk of experimentation. Following weaning, and until the end of the experiment, 11 wk later, they had ad libitum access to grass hay and concentrates at two different levels, ad libitum or restricted, to allow a body weight gain of 700 g/d. A supplement of folic acid (P less than .05) and ad libitum access to feed (P less than .05) increased the mean concentration of serum folates. Blood hemoglobin and packed cell volume were not affected by the level of feed intake. However, they were both increased (P less than .05) by the supplement of folic acid. Average daily gain was analyzed over three different periods: 0 to 5 wk (before weaning), 5 to 10 wk, and 10 to 16 wk. Average daily gain was increased by the supplement of folic acid during the second period (P less than .05) and by ad libitum access to feed during the last two periods (P less than .05). Ad libitum access to feed increased (P less than .05) weight of the liver, decreased the (P less than .05) concentrations of RNA and DNA, and increased (P less than .05) the ratios of protein/DNA and RNA/DNA. The supplement of folic acid decreased (P less than .05) weight of the liver and increased the ratio RNA/DNA (P less than .05). These effects of supplement of folic acid on growth performance and on hematological cells may reflect a lack of folic acid during the weeks after weaning.     

Strategies to reduce feedlot cattle heat stress: effects on tympanic temperature

Three experiments were conducted to evaluate the effect of different management strategies on body temperature of feedlot steers finished in the summer months. In Exp. 1, 24 crossbred steers were chosen to assess the effect of altered feed intake and feeding time on tympanic temperature (TT) response. Managed feeding (MF) treatments were applied for 22 d only and provided 1) ad libitum access to feed at 0800 (ADLIB), 2) feed at 1600 with amount adjusted so that no feed was available at 0800 (BKMGT), 3) feed at 1600 at 85% of predicted ad libitum levels (LIMFD). During heat stress conditions on d 20 to 22 of MF, LIMFD and BKMGT had lower (P < 0.05) TT than ADLIB from 2100 through 2400. A carryover effect of limit-feeding was evident during a severe heat episode (d 36 to 38) with LIMFD steers having lower (P < 0.05) TT than ADLIB. In Exp. 2, TT were obtained from 24 crossbred steers assigned to three treatments, consisting of no water application (CON), water applied to feedlot mound surfaces from 1000 to 1200 (AM) or 1400 to 1600 (PM). From 2200 to 0900 and 1200 to 1400, steers assigned to morning sprinkling treatment had lower (P < 0.05) TT than steers assigned to afternoon sprinkling treatment. In Exp. 3, 24 steers were utilized in a 2 x 2 factorial arrangement of treatments with factors of feeding time [0800 (AMF) and 1400 (PMF)] and sprinkling (WET and DRY). Tympanic temperatures were monitored under hot environmental conditions on d 30 to 32 and 61 to 62. A feeding time x sprinkling interaction (P < 0.001) was evident on d 30 to 32, although AMF/DRY steers had the highest (P < 0.05) TT. On d 61 to 62, TT of PMF steers was higher (P < 0.05) than AMF between 1500 to 1800. Use of sprinklers can effectively reduce TT of feedlot cattle, whereas shifting to an afternoon vs morning feeding time was most beneficial when bunks were empty several hours prior to feeding.     

湿热环境对后备公猪采食行为和饲料效率的影响

为分析中国南方高温高湿环境对扬翔华系杜洛克后备公猪在生长育肥期采食量、采食时间等采食行为和饲料效率的影响,本研究以扬翔华系杜洛克后备公猪在FIRE测定站的998 195条采食记录为基础,使用温湿度自动监测设备实时监测圈舍温度和湿度。采用R 3.5.1软件统计猪群昼夜采食节律,运用线性混合模型分析不同温湿度水平采食行为和饲料效率的差异,并尝试建立扬翔华系杜洛克生长公猪实际采食量预测模型。结果表明:扬翔华系杜洛克生长猪的采食行为呈昼夜节律变化,受日温度变化影响;当环境温度在20～24℃,温湿指数(THI)在66～71时,生长猪的饲料转化率(FCR)和剩余采食量(RFI)均较低;当环境温度超过25℃,THI超过74时,FCR最高可提高13.98%,RFI最高可提高182.92%。综上可知,在华南地区湿热环境下,当环境温度控制在18～22℃、THI在65～70时,扬翔华系杜洛克生长公猪的采食量较高,FCR和RFI较低,饲料效率较高。THI可作为监测生长公猪热应激的候选指标。     

Effects of grouping unfamiliar cohorts, high ambient temperature and stocking density on live performance of growing pigs

Ninety-six crossbred intact male pigs (34.5 +/- 3.5 kg BW) were allocated by weight and vocalization score to a 2 x 2 x 2 dynamic experimental design including two stocking densities (1 or 2 m(2)/pig), two temperatures (22 degrees C and 30 degrees C), and two short groupings of unfamiliar cohorts (six pigs as one pig per group, and six pigs per group). The study was conducted over 8 wk, and live weight gain (WTG) and feed intake (FI; as-fed basis) were measured weekly. During the first week, pigs were housed in individual pens from four independent rooms. To group pigs, pen partitions were removed. Pigs were grouped in Rooms 2 and 3 from wk 2 to 4, and in Rooms 1 and 4 during wk 7. Temperature was increased from 22 degrees C to 30 degrees C in Rooms 1 and 2 during wk 4 and 7. Pen partitions were replaced in Rooms 2 and 3 at the end of wk 4 and in Rooms 1 and 4 at the end of wk 7 to return pigs to their individual pens. Grouping pigs decreased FI during wk 3 (15.08 +/- 0.43 vs. 14.03 +/- 0.41 kg P < 0.10), and during wk 7 (17.42 +/- 0.46 vs. 14.24 +/- 0.41 kg; P < 0.01). In addition, grouping had a negative effect (P < 0.001) on WTG at wk 3 (7.38 +/- 0.28 vs. 5.71 +/- 0.28 kg) and at wk 7 (6.70 +/- 0.26 vs. 2.99 +/- 0.26 kg). For grouped pigs, raising the temperature decreased (P < 0.01) WTG (7.49 +/- 0.29 vs. 6.41 +/- 0.29 kg during wk 4, and 3.37 +/- 0.38 vs. 2.62 +/- 0.38 kg during wk 7). Mean FI was decreased (P < 0.01) with the 30 degrees C treatment during wk 7 only (15.49 +/- 0.33 kg at 22 degrees C compared with 12.99 +/- 0.33 kg at 30 degrees C). Compensatory feed intake was evident after the treatments had ceased at wk 6, whereby previously heat-treated grouped pigs had a higher FI (17.97 +/- 0.45 kg) than the animals individually housed at 22 degrees C (12.99 +/- 0.33 kg). Stocking density effects were noted after the grouping and high temperature treatments had ceased. For instance, during wk 5, low-density-housed pigs grew faster (P < 0.001) than their high-density counterparts (9.04 +/- 0.38 vs. 7.49 +/- 0.29 kg). In conclusion, under the conditions of this study, the grouping of unfamiliar cohorts and high ambient temperature treatments had a detrimental effect on pig performance, and these effects were reversible.     

Endoscopy via a gastric cannula to monitor the development of ulcers in the pars esophagea in pigs after consumption of a finely ground feed combined with a period of withholding of feed

OBJECTIVE: To develop an endoscopic technique for use in monitoring devlopment of gastric ulcers via a gastric cannula during withholding of feed and administration of a finely ground diet to pigs. ANIMALS: 6 pigs weighing between 60 and 70 kg. PROCEDURE: A gastric cannula was surgically inserted adjacent to the pars esophagea in each pig. Pigs were fed a finely ground diet for two 7-day periods that were separated by a 48-hour period during which feed was withheld. Endoscopic examination via the gastric cannula was used to monitor development of ulcers in the pars esophageal region of the pigs during the 48-hour period of feed withhold and subsequent 7-day feeding period. An ulcer score was assigned during each endoscopic examination. A final examination was performed during necropsy and compared with results for the final endoscopic examination. RESULTS: Consumption of a finely ground diet for 7 days resulted in progressive erosive damage to the pars esophageal region of the stomach. Further significant increases in ulcerative damage were detected after 24 and 48 hours of withholding of feed. Final examination during necropsy did not reveal significant differences from results obtained during the final endoscopic examination. CONCLUSIONS AND CLINICAL RELEVANCE: Endoscopic examination via a gastric cannula was an effective means of monitoring ulcer development in the pars esophagea of pigs. Feeding a finely ground diet and withholding of feed induced endoscopically observable ulcers in the stratified squamous epithelial region of the stomach. Direct visual examination during necropsy confirmed the accuracy of endoscopic examination.     

Systematic analysis of feeding behaviors and their effects on feed efficiency in Pekin ducks

Background: Feeding behavior study is important for animal husbandry and production. However, few studies were conducted on the feeding behavior and their relationship with feeding efficiency in Pekin ducks. In order to investigate the feeding behavior and their relationship with feed efficiency and other economic traits in Pekin ducks, we selected 358 male Pekin ducks and recorded feeding information between 3 to 6 wk of age using automatic electronic feeders, and compared the feeding behavior under different residual feed intake(RFI) levels.Results: We observed that total feed time, daily feed intake and feed intake per meal had strong positive correlations with feed efficiency traits; moreover, strong correlation between feed intake per meal and body weight was found(R=0.32, 0.36). Daily feeding rate meal and meal duration had weak correlations with feed efficiency(R=0.14~0.15). The phenotypic correlation of between-meal pauses, with feed efficiency was not observed. When daily changes were analyzed, high RFI ducks had the highest feed consumption over all times, and obvious differences in daily visits were found among different RFI level animals during the middle period; these differences were magnified with age, but there was no difference in daily meal number. Moreover, our data indicate that high RFI birds mainly take their meals at the edge of the population enclosure, where they are more susceptible to environmental interference.Conclusions: Overal, this study suggests that the general feeding behaviors can be accurately measured using automatic electronic feeders and certain feeding behaviors in Pekin ducks are associated with improved feed efficiency.     

夏季发酵床模式与改进水泥地面模式生猪饲养效果比较

为了比较夏季发酵床与改进水泥地面模式保育猪和生长猪饲养效果,选择日龄相近、生长发育良好的杜×长×大三元配套系商品猪,初始体重分别为（9.59±0.81）kg保育猪88头和（18.43±1.32）kg生长猪64头,随机分成发酵床模式组和改进水泥地面模式组。保育猪饲养期为31d,生长猪饲养期为57d。全程记录饲养期间每天猪舍内温度、湿度、地面温度。结果表明,改进水泥地面模式舍内温度、地面温度和相对湿度均低于发酵床模式。改进水泥地面模式与发酵床模式相比,保育猪日增重提高14.6%、料重比降低11.7%;生长猪日增重无显著差异,但料重比降低9.8%。夏季保育猪和生长猪在改进水泥地面模式下的饲养效果优于发酵床模式,建议南方地区发酵床只用于夏季以外季节的保育猪饲养。     

Effects of feeding systems on social and feeding behavior and performance of finishing pigs

Two experiments were conducted to study the effects of feeding systems on feeding behavior, aggression, social ranks and average daily gain (ADG) of pigs. In Exp. 1, feed was delivered during the day from 1100 to 1400 and at night from 2300 to 0200. One pen containing 10 barrows and 10 gilts was used. Correlation coefficients were calculated between pairs of traits. In Exp. 2, four feeding systems were tested using similar group composition as in Exp. 1. Two feeding systems were ad libitum, offering either dry or wet feed; the other two used time-restricted feeding from 0900 to 1100 and from 1600 to 1800, but with water supplied either ad libitum or time-restricted. Analyses of variance were used to test feeding system effects; correlation coefficients were calculated for pairs of traits. Results of Exp. 1 indicated that pigs displayed predominantly daytime activities. Frequency of aggressive acts were correlated significantly with feeding frequency (r = .48), time to first feeding (r = -.50) and ADG (r = .56). In Exp. 2, pigs on time-restricted feeding with ad libitum water had significantly depressed ADG and reduced feed intake. A possible association between time-restricted feeding and water intake is postulated. Feeding behavior, aggression and social rank were associated with ADG in time-restricted systems but not in ad libitum systems. There was a tendency in time-restricted-fed pigs for the more aggressive pigs to perform more feeding activities, to rank higher in the social order, and to gain faster.     

饲喂模式对生长育肥猪胴体品质和脂质代谢的影响

本试验旨在研究饲喂模式对生长育肥猪生长性能、胴体品质和脂质代谢的影响。试验选择48头平均初始体重为(61.4±2.5)kg的杜×长×大三元杂交去势公猪,根据体重按随机区组设计分到自由采食组(自由采食)和限制饲喂频率组(每天饲喂2次)。每个处理8个重复,每个重复3头猪。结果表明:限制饲喂频率组的平均日采食量(ADFI)、平均日增重(ADG)、胴体重、屠宰率和平均背膘厚均显著低于自由采食组(P0.05);饲喂模式对猪肉品质相关指标无显著影响(P0.10);限制饲喂频率组脂肪组织中苹果酸酶(ME)和脂肪酸合成酶(FAS)的活力显著低于自由采食组(P0.05);限制饲喂频率组脂肪组织中FAS和过氧化物酶体增生物激活受体γ(PPARγ)的m RNA表达量显著低于自由采食组(P0.05)。综上分析,限制饲喂频率降低了生长育肥猪的生长性能、胴体品质和脂肪沉积,但对肉品质无显著影响,其中限制饲喂频率主要是通过降低脂肪合成减少脂质沉积。     

Use of carbohydrate and fat as energy source by obese and lean swine

Genetically obese and lean pigs were fed isonitrogenous-isoenergetic (digestible energy) amounts of a high or low fat diet from 25 kg body weight. Obese pigs gained less and required more feed per unit gain than lean pigs. Lean pigs were more muscular with less fat than obese pigs. Obese pigs utilized more dietary amino acids for energy (greater plasma urea N) than did lean pigs. Weight gain was similar at all intermediate periods in obese pigs fed the two diets. However, gain tended (P less than or equal to .10) to be greater and the ratio of dietary energy intake to gain tended (P less than or equal to .10) to be less in obese pigs fed high compared with low fat diets. Similar results were observed in lean pigs fed the two diets. The high fat diet produced more carcass adipose tissue deposition in both strains after 20 wk of feeding (detectable by ultrasound at 14, but not at 7 wk). Adipose tissue lipogenic rate (glucose incorporation) was similarly depressed by fat feeding in both obese and lean pigs. Obese and lean pigs both utilized dietary carbohydrate and fat differentially but there was no indication of genetic divergence regarding this utilization. In both strains of pigs, energy from the fat-enriched diet was preferentially partitioned into carcass adipose tissue.