Studies On Design Theory And Application Technology Of Self-Help Wet-Dry Feeder For Swine

It is still a serious problem that feed waste and environmental pollution caused by conventional or backward feeders and feeding style in recent swine production in China. In order to reduce feed waste and environmental pollution radically in pig production, these experiments as follows were mainly conducted. 1) Design and trial-manufacture of wet/dry feeders for weaned pigs and for growing-finishing pigs. 2) Effects of wet/dry Feeders on performance of weaned pigs and approach to the mechanism (including Exp.l and Exp.2). 3) The optimal dietary digestible energy (DE)and crude protein(CP) for weaned pigs using wet/dry feeders (Exp.3). 4) Effects of wet/dry feeders on performance of growing-finishing pigs and approach to the mechanism (including Exp.4 and Exp.5). 5) The optimal dietary DE and CP for growing-finishing pigs fed by wet/dry feeders (Exp.6). 6) Economic analysis of manufacturing and applying the wet/dry feeders.In Exp.l, a total of 120 Duroc X Landrace X L.Youkshire (DLY) crossbred piglets (approximately 28+1 days old) were selected and allotted to two treatments, each with 3 replicates to determine the effects of dry-wet feeder and concrete trough on growth performance of weaned piglets for a 42-d feeding trial. In Exp.2, the same amount of piglets in Exp.l was divided into two treatments, each with 3 replicates to determine the effects of different feeds, mash or pellet on growth performance of weaned piglets for a 42-d feeding trial. At the end of these two feeding trails, three barrows and three gilts per treatment were bled to collect serum. In addition, the digestive experiments, with acid insoluble ash as indictor, were conducted at three days before the end of feeding trial.Six hundreds of piglets were divided into 5 treatment groups, each with 3 replicates to study the optimal dietary DE and CP for weaned pigs fed by wet/dry feeders in Exp.3. During the whole feeding period, pigs of each group were all fed one of mash diets containing DE13.82MJ/kg /CP20% (groupDl), DE13.61/CP19 (groupD2), DE13.40/CP18 (groupD3), DE13.19/CP17 (groupD4) and DE12.98/CP16 (groupD5). Feed and water were offered via dry-wet feeder ad libtum. At the end of feeding trail, all treatments groups pigs were weighed individually and feed consumed were recorded. Three barrowsand three gilts in each treatment were bled to collect serum.A total of 168 pigs were allotted to 2 treatment groups, each treatment with 4 replicates to evaluate the effect of wet/dry feeders and concrete trough on the performance of growing-finishing pigs in Exp.4.In Exp.5, 432 pigs was selected and paired randomly to two groups(wet/dry feeder and concrete dry feeder), with every replicates containing 36 pigs(18 pigs per pen). In the digestive experiments, with acid insoluble ash as indictor, were conducted at three days before the end of feeding trial. 24 pen pigs (20~35kg) were compared to examine the effect of different feeders on the digestibility of energy (GE) and crude protein (CP) of growers. In behavior observation Experiment, 288 growing pigs (35~60kg) were used to evaluate the influence of wet/dry feeder on the feeding and drinking frequency of growers in the evening. Direct observations were also made of the entire pen for about 10 min to record behaviors.In Exp.6, five hundreds and sixty pigs were allotted to 5 treatment groups, each treatment with 4 replicates to determined the optimal digestible energy and crude protein levels and discussed the mechanism by feeding trial, measuring meat traits, serum and hormone biochemical parameters. The whole feeding trial was divided into three periods, each of wet-dry feeder groups were fed the meal diets with ad libitum, At approximately 35kg (BW), three barrows and three gilts per treatment were bled to collect serum. In addition, the digestive experiments with acid insoluble ash as indictor, were conducted at three days before the end of 20-35kg period and 60-90kg period. At the end of feeding trail, three barrows and three gilts, approximately 90 kg (BW), in each treatment were slaughtered to determine carcass composition and loin traits.at the same time, blood samples were collected.The results obtained are as follows.(1) A type of wet/dry feeder was designed and trail-manufactured successfully (Patent No. ZL 00 2 68461.6).(2) The performance of weaned pigs and growing-finishing pigs fed by wet/dry feeders could be improved, compared to concrete trough. During whole feeding period from 28 to 70d of age, ADG and ADFI of pigs with dry-wet feeder were increased by 12.5%(P<0.01), 6.4%(P<0.05) and F/G was decreased by 5.64%(P<0.01) respectively, compared to those with concrete troughs. ADG and ADFI of growing-finishing pigs with dry-wet feeders comparing with concrete troughs were increased by 9.7%(P<0.01), 4.6%(P<0.05) and F/G was decreased by 8.4%(P<0.01) respectively during 20-90 kg period. There was no difference in ADG of growing-finishing pigs fed pelleted diets by wet/dry feeders and by concrete dry feeders, but ADFI or F/G of the group using wet/dry feeders was lowered by 6.40% (p<0.005) during 20~90kg period, the performance of weaned piglets using wet/dry feeders did not differ significantly between mash and pellet diets during 28-70d period (p>0.05).(3) The digestive trails showed that using wet-dry feeders could increase apparent digestibility of DM or GE and CP for weaned piglets by 2.6% (P<0.05) and 2.7% (P<0.05) during 28-70d period compared to the control, respectively and also increase apparent digestibility of GE and CP for 20-35kgand 4.1% (p<0.05) compare to the control, respectively. No difference was found in apparent digestibility of GE and CP between growers fed pellet feed by wet/dry feeders and concrete dry feeders.(4) The datum obtained from serum analysis showed that compared to control, using wet/dry feeders could increase weaned pigs' and growing-finishing pigs' gasrtin (GAS) content significantly. Compared to the control, GAS content was increased by 51.0% (p<0.05) in weaned pigs and by 65.80% (p<0.05) in growers and by 20.46% (P>0.05) in finishers with wet/dry feeders during the whole trail period. GLU, TP, SUN, AKP and T3 and T4 in pigs fed by wet/dry feeders were higher (p>0.05 ) . There was a contrary trend with AKP and TP compared to SUN among treatments. According to the analysis of digestive enzymes activities in duodenal contents, using wet-dry feeder could improve the activity of proteolytic enzyme, amylase and lipase by 31.7%(p=0.077), 44.7%(p=0.058), and 91.9%(p<0.05) compared to the control, respectively.(5) The performance, apparent digestibility of GE and CP and GAS content of weaned pigs and growing-finishing pigs fed by wet/dry feeders were significantly influenced by different dietary DE and CP levels. There differences in apparent digestibility of GE and CP among experimental groups. All of targets for different aged pigs received suitable dietary DE and CP levels were significant higher(P<0.05) than those received the highest or lowest.(6) Experiments showed that there were no negative effects of wet/dry feeders on carcass composition and loin meat quality in finishers and no significant difference (P>0.05) in carcass composition and loin meat quality among five treatments received different dietary DE and CP levels with wet/dry feeders.(7) It is suggested, according to the results of feeding trials, digestive experiments and serum analysis, that the optimal dietary DE and CP for DLY hybrids fed by wet/dry feeders are DEI 3.41 — 13.61 MJ/kg and CP18~19% for weaned piglets during 28-70d period, DE 12.79—12.99MJ/kg and CP17—18% for growing pigs during 20-35kg, DE 12.43—12.61MJ/kg and CP15~16% for growers during 35-6Okg and DE 12.38—12.56MJ/kg and CP14~15% for finishers during 60-90kg period, respectively.(8)The results of behavior observation Experiment showed that, for 35-60kg growers, the feeding frequency of the group using wet/dry feeders was higher than the control during the period 18:30~19:30(p<0.05) and during the period 20:30-21:30(p<0.05). And the drinking frequency of the experimental group was lower. The higher feeding frequency indicated that growers fed by wet/dry feeders have stronger social hierarchy among themselves and less fighting on feeding which caused great amount of wasting feed. The higher drinking frequency of the control suggested pigs using concrete feeders visit the drinkers more frequently, thus increase the probability of wasting feed on the way from feeders to drinkers.(9) According to the results of the studies the mechanism of improving growth performance and saving feed by using wet/dry feeders might be elucidated as follows. Feed intake and drinking combination could reduce feed waste in the course of drinking while feeding. Shortened feeder could...