Social hierarchy in suckling and fattening pigs: A review

This brief account of recent work on social hierarchy and its relation to production and disease in the domesticated pig covers the development of the teat order and its influence (if any) on the dominance hierarchy, the mechanisms by which previously unacquainted pigs sort themselves out into a social order, the leadership hierarchy, the factors affecting the stability of the dominance hierarchy, and the way in which a breakdown of the normal social order may contribute to outbreaks of aggression (e.g. tail-biting and cannibalism) within previously contented groups of pigs. A plea is made for further work on some of these important behavioural areas.     

Alterations of the integument of fattening pigs in different housing systems

Alterations of the integument of fattening pigs were investigated on a total of eleven farms with the following housing systems: "Krieger" system, fully slatted floors, partially slatted floors and kennel housing systems. For this purpose, the alterations of the integument of the animals were visually assessed at different times during fattening. In addition, spot investigations were carried out on three farms with deep litter systems. In the non-littered systems, significantly more changes at the limbs were observed than in the littered systems. The least damages occurred in the deep litter system. Similar as with cattle, soft and deformable lying areas seem to be a prerequisite for the prevention of such alterations. With respect to injuries caused by tailbiting, apart from possibilities of activity, other parameters such as air quality and space availability also play an important role.     

Electromechanical registration of the resting behavior of fattening pigs]

The resting behaviour of four weanling pigs has been continuously recorded by an electromechanical apparatus for 8 weeks. The duration of different postures: standing, ventral recumbency, lateral recumbency and frequency of standing periods were recorded as influenced by different environmental factors. 1. Floor with and without bedding at 21 degrees C. 2. Floor without bedding at 27 degrees C environmental temperature. 3. Feeding once daily versus twice. Duration of recumbency periods was increases at 21 degrees C if bedding was provided. This also improved daily gain. At elevated environmental temperatures the animals preferred the lying posture on concrete floor. Feeding twice increased the duration of recumbency. The same was the case as the animals grew older. Disturbance by caretaking activities in neighbouring dens increased the duration of standing.     

Intermittent suckling during an extended lactation period: effects on piglet behavior

The objectives of the current study were to determine how intermittent suckling (IS) affects nursing behavior, litter activity, and general behavioral patterns during lactation, and whether IS during an extended lactation period results in behavioral patterns associated with piglet distress. Intermittent suckling was applied either with 6-h separation intervals (IS6) or with 12-h separation intervals (IS12) and was compared with the conventional treatment (CT). In the CT (n = 17 litters), sows were continuously present until weaning (d 21, d 0 = farrowing). In both IS6 and IS12, sows were separated from their litter for 12 h/d, beginning at d 14 and lasting until weaning (d 43 +/- 1 d). In IS6, litters (n = 14) and sows were separated from 0800 to 1400 and from 2000 to 0200; in IS12 litters (n = 14) and sows were separated between 0800 and 2000. In IS litters, the activity pattern over the 24-h cycle was markedly changed by IS; litter activity was lower (P < 0.001) during sow absence and greater (P < 0.001) during sow presence compared with the unweaned CT litters. Moreover, both total nursing frequency (P < 0.001) and the percentage (P < 0.002) of successful nursings were reduced by IS. Although total nursing frequency was greater in IS6 compared with IS12 (on d 21 and 28), no differences in the frequency of successful nursings existed between IS6 and IS12 from d 14 onward. Eating behavior was increased shortly after the onset of IS (d 17) in both IS6 (P = 0.059) and IS12 (P < 0.001) compared with the unweaned CT litters. The IS12 litters showed more eating behavior compared with IS6 and their exploratory behavior increased in time (P < 0.001), whereas IS6 showed more nursing behavior. Aggressive or manipulative behavior of both IS treatments was similar compared with the unweaned CT, and remained relatively unaltered with time in IS12 and IS6. Weaning in the CT resulted in more manipulative (P < 0.001) and aggressive (P = 0.004) behavior compared with pre-weaning values. Intermittent suckling may contribute to adaptation to the postweaning state by stimulating eating behavior, without causing obvious behavioral distress.     

Immunocompetence of fattening pigs fed organic versus conventional diets in organic versus conventional housing

The effect of organic or conventional feeding on the immune response of pigs was determined using organic or conventional housing in a pig fattening unit. The experimental design involved four pens of four animals per housing and diet combination (organic housing and organic nutrition; organic housing and conventional nutrition; conventional housing and organic nutrition and conventional housing and conventional nutrition). The IgM, IgA and IgG responses against intramuscularly injected bovine thyroglobulin were determined as indicators of the antigen-specific immune responsiveness. Some general health and welfare related parameters were evaluated by measuring haptoglobin concentrations at selected times; blood lactate concentration was measured at slaughter. Conventional housing led to a higher IgG response three weeks after the first immunisation. Organic housing led to lower haptoglobin and lactate concentrations at slaughter, indicating a higher stress resistance in these pigs. No major differences between the two feeding types were found. We conclude that the immune responses following either a conventional or an organic diet are comparable, whereas organic housing can increase stress resistance at slaughter compared to conventional housing.     

不同绿色添加剂组合对生长育肥猪生产性能的影响

试验选择90头平均体重为（18.7+2.1）kg的杜×长×本三元杂交断奶仔猪,按单因子随机试验设计分为3组,每组3个重复,每个重复10头仔猪进行试验。对照组饲喂基础日粮+10mg/kg速大肥;试验1组饲喂基础日粮+0.1％生命素+0.05％迈克活菌酶;试验2组饲喂基础日粮+200mg/kg糖萜素+0.03％迈克活菌酶+0.05％。生命素。各组基础日粮完全相同。结果三组供试猪的平均日增重分别为670.25,667.83和647.08g（P>0.05）,料重比分别为3.23,3.09和3.11（P<0.05）,扣除实际耗料成本,每头猪实际赢利分别为97.26,92.90和93.77元,两试验组的生物学综合评定值分别为104.17和 101.86。     

Prevalence of campylobacter in pigs during fattening; an epidemiological study

Summary

Numerous epidemiological reports implicate foods of animal origin as vehicles of human campylobacteriosis. Pigs are probably an important reservoir of campylobacter and a potential source of human infection. In order to improve our knowledge of the epidemiology of campylobacter in pigs, the prevalence of campylobacter and its contamination of feed were monitored in eight pig farms. Faeces samples of pigs aged 11 and 22 weeks, and samples of rectal, ileal and gastric content at a slaughterhouse were collected for bacteriological examination. On 5 farms, subsequent groups of pigs housed in the same stalls was sampled, too. A selection of the campylobacter isolates was characterized with a genetic typing method (RFLP). More than 85% of the sampled porkers were shown to be intestinal carriers of campylobacter at all stages of fattening. Subsequent groups of pigs housed in the same stalls were all carriers, too. The level of campylobacters in the faeces tended to decrease as the pigs got older. There was no difference in the frequency and level of infection with campylobacter between porkers on different farms. The feeding system (wet feed versus dry pellets) did not seem to influence the prevalence of campylobacter although wet feed gave lower counts of Enterobacteriaceae in the faeces.

RFLP‐typing showed a high diversity of campylobacter strains at each sampling on the farm. Similarities were seen between strains isolated during two subsequent samplings of the same group of pigs, but not between strains isolated on the same farm from subsequent groups of pigs housed in the same stall. This suggests that the piglets were already infected at a young age on the breeding farm.     

Maternal influence mediated by litter size during the suckling period on reproduction traits in pigs

Maternal effects might affect the response to selection for litter size. An experiment was carried out to determine the effect of the size of litter in which a gilt was raised on its production and reproduction characteristics. Gilts raised in large litters (12 piglets) produced smaller litters (?0.48 piglets) compared to those raised in small litters (six piglets). Results obtained suggest that a low standardization level positively affects weaning weight and development of the uterus. Lower weight at weaning, in combination with a larger pool of primordial follicles, might explain the positive effect on litter size.     

Effects of housing finishing pigs in two group sizes and at two floor space allocations on production, health, behavior, and physiological variables

With the current shift in the industry toward housing pigs in groups of 100 to 1,000 per pen have come questions as to whether pigs can perform as well in large groups as they do in small and whether large groups of pigs can use the space provided more efficiently. This study examined effects of small (18 pigs) vs. large (108 pigs) group sizes provided 0.52 m(2)/ pig (crowded) or 0.78 m(2)/pig (uncrowded) of space on production, health, behavior, and physiological variables. Eight 7-to 8-wk-long blocks, each involving 288 pigs, were completed. The average BW at the beginning of the study was 37.4 +/- 0.26 kg. Overall, ADG was 1.032 kg/d and 1.077 (+/-0.015) kg/d for crowded and uncrowded pigs, respectively (P = 0.018). Differences between the space allowance treatments were most evident during the final week of study. Overall G:F was also reduced (P = 0.002) in the crowded treatment. Pigs in the crowded groups spent less (P = 0.003) time eating over the 8-wk study than did pigs in noncrowded groups, but ADFI did not differ (P = 0.34) between treatments. Overall, ADG of large-group pigs was 1.035 kg/d, whereas small group pigs gained 1.073 kg/d (+/-0.015; P = 0.039). Average daily gain differences between the group sizes were most evident during the first 2 wk of the study. Over the entire study, G:F also differed, with large groups being less efficient (P = 0.005) than small groups. Although large-group pigs had poorer scores for lameness (P = 0.012) and leg scores (P = 0.02) throughout the 8-wk period, morbidity levels did not differ (P = 0.32) between the group sizes. Minimal changes in postural behavior and feeding patterns were noted in large groups. An interaction (P = 0.04) of group size and space allowance for lameness indicated that pigs housed in large groups at restricted space allowances were more susceptible to lameness. Although some behavioral variables, such as lying postures, suggest that pigs in large groups were able to use space more efficiently, overall productivity and health variables indicate that pigs in large and small groups were similarly affected by the crowding imposed in this study. Broken-line analysis of ADG indicated no difference in the response to crowding by pigs in large and small groups. Little support was found for reducing space allowances for pigs in large groups.     

三种微生态制剂对哺乳母猪、哺乳仔猪及保育猪的应用效果研究

本研究通过对长×大二元杂交哺乳母猪、皮×杜×长×大四元杂交哺乳仔猪、保育猪分别使用利生菌王、益牧宝、方便菌3种不同微生态制剂进行效果试验,结果表明:利生菌王能显著提高哺乳母猪、哺乳仔猪的生长性能,益牧宝对保育猪的生长性能的提高效益较好。     

Studies on the performance-related lysine requirement in fattening pigs. 1. Influence of energy and aminoacid intake on fattening

A total of 110 barrows fed varying levels of energy and amino acids in 8 treatments, were tested. The weight gains per fattening day and energy expenditure were found to be mainly determined by energy intake. Up to a liveweight of 100 kg both low and high levels of amino acid supply produced the same fattening performance results as amino acid supply to standard. In the 100-120 kg liveweight range, the animals fed higher levels of protein proved slightly superior. As to energy expenditure, animals subjected to restricted feeding up to 70 kg liveweight and fed full rations later, consumed 2.22 kEFs (2.22 kilo energetic feed equivalents/swine) per kg gain and proved significantly superior to those animals that were very intensively fed at the beginning and put to restricted feeding beyond 70 kg liveweight (2.53 kEFs per kg gain) as well as to those receiving high levels of energy all the time (2.39 kEFs/kg gain). In the latter case, 23 g of lysine were required per kg gain.     

Developmental changes in intercellular junctions and Kv channels in the intestine of piglets during the suckling and post-weaning periods

Background: The intestinal epithelium is an important barrier that depends on a complex mixture of proteins and these proteins comprise different intercellular junctions. The purpose of this study was to investigate the postnatal and developmental changes in morphology, intercellular junctions and voltage-gated potassium(Kv) channels in the intestine of piglets during the suckling and post-weaning periods.Results: Samples of the small intestine were obtained from 1-, 7-, 14-, and 21-d-old suckling piglets and piglets on d 1, 3, 5, and 7 after weaning at 14 d of age. The results showed that the percentage of proliferating cell nuclear antigen(PCNA)-positive cells and alkaline phosphatase(AKP) activity, as well as the abundances of E-cadherin,occludin, and Kv1.5 m RNA and claudin-1, claudin-3, and occludin protein in the jejunum were increased from d 1to d 21 during the suckling period(P 0.05). Weaning induced decreases in the percentage of PCNA-positive cells,AKP activity and the abundances of E-cadherin, occludin and zonula occludens(ZO)-1 m RNA or protein in the jejunum on d 1, 3 and 5 post-weaning(P 0.05). There were lower abundances of E-cadherin, occludin and ZO-1m RNA as well as claudin-1, claudin-3 and ZO-1 protein in the jejunum of weanling piglets than in 21-d-old suckling piglets(P 0.05). The abundances of E-cadherin, occludin, ZO-1 and integrin m RNA were positively related to the percentage of PCNA-positive cells.Conclusion: Weaning at 14 d of age induced damage to the intestinal morphology and barrier. While there was an adaptive restoration on d 7 post-weaning, the measured values did not return to the pre-weaning levels, which reflected the impairment of intercellular junctions and Kv channels.