Housing During Early Pregnancy Affects Fertility and Behaviour of Sows

From 1.1.2013 EU legislation will permit stall‐housing of dry sows for only 4 weeks post‐service. Stalls are associated with compromised animal welfare, but group housing comes with risks from social confrontations. Studies on housing effects on fertility have produced contradictory results as systems are inconsistently defined. Effects of housing on pregnancy rate 28 days post‐service (P28), early disruption of pregnancy (EDP) and behaviour were investigated in 12 replicates of 40 sows. Half of the animals were stalled (treatment S, mean parity 2.4) and half group‐housed adjacent on 5.1 m² deep litter per sow (treatment G, mean parity 2.3). Pregnancy was detected using real‐time ultrasound. An EDP‐diagnosis required a drop of salivary progesterone concentration from >15.9 to <15.9 mmol/l in a series of samples taken on days 17, 20, 24 and 27 post‐service. Behaviour was scan sampled on day 27 for 120 min with 10‐min intervals. Data was analysed using mixed regression models in MLwiN. Treatment S increased the odds for P28 with 2.3 and the pregnancy rate of a treatment group with 0.1 compared with G. G increased the odds for EDP with 4.6. Treatment did not affect total exploratory or total passive behaviour. S sows explored floor and fixtures (not bedding) more and performed more passive sitting than G sows. Social stress may have caused the impaired reproductive performance in G sows. S sows showed behavioural signs of decreased welfare, but no corresponding reproductive effects. An interdisciplinary approach is needed when evaluating the appropriateness of housing systems.     

REVIEWS: Compilation of the Scientific Literature Comparing Housing Systems for Gestating Sows and Gilts Using Measures of Physiology,Behavior, Performance,and Health

The objective of this review was two-fold. First, a series of meta-analyses (analyses of treatment effects across studies) were performed on available data from scientific literature to determine whether sow behavior, performance, or physiology differed for sows in group pens or individual stalls. Second, research publications in areas of performance and health, physiology, and behavior of pregnant gilts and sows in studies that directly compared gestation sow housing systems were summarized. Common systems were stalls, tethers, and various types of group housing systems. Results of meta-analyses showed that the average levels of productivity, oral-nasal-facial behaviors (ONF), and blood cortisol were statistically similar for sows in group pens and stalls. For the review, in some studies, circulating cortisol concentrations were greater among gestating females kept in tethers compared with other systems; however, overall cortisol was not altered by housing system. Immune parameters were largely not influenced by housing system. Housing system did not alter heart rate. Gestation housing system may influence sow behavior including stereotypic ONF, postural locomotory, feeding behaviors, or social behaviors. Overall, total ONF behaviors were comparable between gestation sow housing systems. However, tethered and stalled sows exhibited more stereotypic ONF compared with sows in group or outdoor systems. Compared with group housing, individually confining sows during gestation resulted in postural and movement restrictions. Stall size and design can impact postural adjustments and inter-stall aggression of individually housed sows. Inconsistent performance and health results were found among sow housing studies. Sows in stalls consistently had equal or greater reproductive performance compared with sows in other systems. Farrowing rate for sows in individual stalls was equal to or superior to sows in other systems. Farrowing rate was clearly superior among sows in stalls compared with group systems, where dynamic social groups were employed. However, tethered sows may have reduced litter size and increased piglet birth weight. Sows in group housing systems, particularly electronic sow feeder (ESF) systems, had injury scores greater than sows in either stalls or tethers. Gestation housing system (individual vs group) may impact sow welfare in the farrowing area (using stalls or pens). In conclusion, although individual studies found significant housing system effects, subjected to the overall evidence from adequately designed studies meta-analyses revealed that gestation stalls (non-tethered) or well-managed pens generally (but not in all cases) produced similar states of welfare for pregnant gilts or sows in terms of physiology, behavior, performance, and health.     

Ovarian Activity and Oestrous Signs among Group-Housed, Lactating Sows: Influence of Behaviour, Environment and Production

Animal welfare concerns require the development of housing systems that allow the animals to express their natural behaviour. One example of this is the group-housing system for lactating sows. The present study aimed at exploring ovarian activity in such a system. Thirty-eight sows farrowing individually outdoors during spring and summer, and indoors during autumn and winter, and group-housed in groups of four during weeks 3-7 of the lactation period, were monitored regarding reproductive functions, behaviour and production during their first to fourth lactation period. Average ovulation frequency during lactation was 47%. Only 50% of these ovulating cases were accompanied by a standing oestrus. Lactational ovulation frequency was higher in later parities (p < 0.001). Ovulation frequency was higher (p < 0.05) during winter (74%) and spring (69%), than during summer (10%) and autumn (23%). Occurrence of lactational ovulation was associated with some aspects of suckling behaviour and also with litter weight gain (p < 0.05). Forty-nine per cent of the lactational ovulations occurred during the seventh week of lactation. Timing of ovulation seemed positively (p = 0.08) associated with weight loss during lactation. Compared with the sows that were anoestrus during lactation, oestradiol-17beta values were higher (p < 0.05) only in the week before occurrence of lactational ovulation. Weaning-to-oestrous interval was prolonged (p < 0.05) among the sows that ovulated during lactation. The present study identifies several factors influencing ovarian activity among group-housed sows, thereby providing tools for the control of lactational ovulation in group-housing systems.     

Comparison of injuries in sows housed in gestation stalls versus group pens with electronic sow feeders

OBJECTIVE: To compare the location and severity of injuries in pregnant sows housed in individual gestation stalls with that in pregnant sows housed in dynamic groups in pens with electronic sow feeders. DESIGN: Prospective study. ANIMALS: 100 pregnant sows of parity 1 to 3 and various body weights. PROCEDURE: Fifty sows each were randomly allotted to gestation stalls or group pens with electronic sow feeders. Injuries were scored on the basis of location, number, and depth of wounds. Injury scores for sows in both housing systems were compared during a period of 90 days. The influence of factors such as duration of stay in the housing system, parity, and body weight on sow injuries was also examined. RESULTS: Injury scores were higher in group pens with electronic sow feeders. As body weight increased, injury scores decreased for sows housed in group pens with electronic sow feeders and increased for sows housed in gestation stalls. There was a significant negative association between second parity and total injury scores. CONCLUSIONS AND CLINICAL RELEVANCE: Modifications in housing system design and management procedures are needed to reduce injuries in pregnant sows.     

Evaluation of welfare and productivity in pregnant sows kept in stalls or in 2 different group housing systems

One hundred eighty pregnant sows (Sus scrofa), from first to ninth parity, on a commercial farm were selected and used in 3 different replicates (60 sows per replicate). Sows were housed from day 29 of pregnancy to 1 week before parturition in conventional stalls, in groups of 10 with trickle feeding or in groups of 20 with an unprotected electronic sow feeder (Fitmix; 20 sows per housing system per replicate). All the sows were equally feed restricted. Behavior, acute-phase protein (APP) plasma levels, and productivity were assessed. General activity and stereotypies were measured by scan-sampling observation at different times of the day on 11 nonconsecutive days. Overall, sows in groups with Fitmix showed an increase in resting behavior and a greater decrease in the frequency of oronasofacial stereotypies than sows in groups fed by trickle feeding (P < 0.001). Sows in the group-housing system showed a decrease in the frequency of sham chewing (P < 0.001). Gilts showed a lower general activity and frequency of stereotypies than older sows in all of the systems (P < 0.001). In general, APP levels and productivity measures did not differ across systems. However, lameness and vulva injuries were more often detected in group-housing systems. Removal of animals was more frequent in sows with Fitmix than in the other systems. In conclusion, well-managed, group-housed sows seem to increase resting behavior and decrease stereotypies at similar productivity and tissue damage levels. However, higher quality stockmanship may be required for early detection and resolution of problems in group-housing systems. Nevertheless, long-term effects of group-housing systems on welfare should be further assessed before recommendations are made.     

A 25?years experience of group-housed sows–reproduction in animal welfare-friendly systems

Since January 1 2013, group housing of sows has been compulsory within the European Union (EU) in all pig holdings with more than ten sows. Sows and gilts need to be kept in groups from 4 weeks after service to 1 week before the expected time of farrowing (Article 3(4) of Directive 2008/120/EC on the protection of pigs). The legislation regarding group housing was adopted already in 2001 and a long transitional period was allowed to give member states and producers enough time for adaptation. Even so, group housing of sows still seems to be uncommon in the EU, and is also uncommon in commercial pig farming systems in the rest of the world. In this review we share our experience of the Swedish 25 years of animal welfare legislation stipulating that sows must be loose-housed which de facto means group housed. The two most important concerns related to reproductive function among group-housed sows are the occurrence of lactational oestrus when sows are group-housed during lactation, and the stress that is associated with group housing during mating and gestation. Field and clinical observations in non-lactating, group-housed sows in Sweden suggest that by making basic facts known about the pig reproductive physiology related to mating, we might achieve application of efficient batch-wise breeding without pharmacological interventions. Group housing of lactating sows has some production disadvantages and somewhat lower productivity would likely have to be expected. Recordings of behavioural indicators in different housing systems suggest a lower welfare level in stalled animals compared with group-housed ones. However, there are no consistent effects on the reproductive performance associated with different housing systems. Experimental studies suggest that the most sensitive period, regarding disturbance of reproductive functions by external stressors, is the time around oestrus. We conclude that by keeping sows according to the pig welfare-friendly Directive 2008/120/EC, it is possible to combine group-housing of sows with good reproductive performance and productivity. However, substantially increased research and development is needed to optimize these systems.     

Urinary cortisol as an additional tool to assess the welfare of pregnant sows kept in two types of housing

The use of urinary cortisol (UC) as an additional tool to evaluate sows welfare was assessed in two experiments. In a preliminary methodological experiment, the kinetics of cortisol excretion in urine was studied during an Adreno Cortico Trophic Hormone (ACTH) challenge test in 10 pregnant sows. In a second experiment, 96 primiparous sows of an experimental unit were assigned to two different housing systems: 48 animals were housed in individual pens (IP) and 48 animals in collective pens (CP) with 6 animals per pen. UC was measured at the beginning and at the end of pregnancy and compared with other welfare indicators such as behaviour or skin damage. In both experiments, UC was measured using a high pressure liquid chromatography assay. In experiment 1, UC was constant on the day before injection of ACTH, with no variations related to circadian rhythm. It began to rise 2 h after the injection, peaked between 2 to 5 h after then returned to the basal concentration on the day after the injection. In experiment 2, UC concentrations were not different between CP- and IP-housed sows but they were higher in sows exhibiting the less stereotypies in comparison with sows exhibiting the most stereotypies. The results of this study suggest that UC is a good indicator of acute stress, more convenient than plasma cortisol measurement since it is a non-invasive method avoiding restraint or catheterisation of sows. They also suggest that UC could also give additional information on the assessment of chronic stress and improve the evaluation of animal welfare if used in conjunction with other welfare indicators.     

Ethological basis for the evaluation of animal welfare in housing systems for agricultural animals and laboratory animals]

The Swiss Federal Act on Animal Protection (1978) requires the sale of mass-produced housing systems for farm animals to be authorized by the Federal Veterinary Office. Authorization is only granted for housing systems that safeguard the animals' welfare. A concept for the assessment of Animal Welfare has to provide a high forensic value. The capacity of farm animals to adapt to an intensive housing system can be directly examined, whereas the existence and extent of subjective feelings can only be assumed. In our concept the examination focuses on the interaction of individuals with their artificial environment. The main question is whether or not the individuals are able to cope with given nonspecific (e.g. temperature, humidity) and specific (e.g. drinking troughs, behaviour of conspecifics) stimuli in order to reach the immediate (e.g. drinking, make way for) and ultimate (survival, reproduction success) goals. Animals of the same breed are observed in a highly diverse environment in order to determine normal behaviour. Whether behavioural expressions which differ significantly from normal behaviour are adaptive to the restrictive housing conditions is judged by the behaviours' consequences for both, the individuals and the environment. Many studies prove the concept's high forensic value and the authorities prefer conclusions based on this concept to others referring to the animals' motivational and emotional state. However more research has to be done with respect to animal welfare in farm and laboratory animal breeding as well as in the use of laboratory animals for experimental studies.     

A review of the effect of energy intake on pregnancy rate and litter size-discussed in relation to group-housed non-lactating sows

The number of group-housed non-lactating sows is increasing rapidly in Europe as a consequence of changed legislation initiated by elevated public concern of animal welfare. Lower litter size and pregnancy rate in group compared to individually housed non-lactating sows have been observed in several on-farm experiments. The overall aim of this paper is to consider whether the variation in energy intake in a group of non-lactating sows can influence variation in litter size and pregnancy rate. A review of existing literature with main emphasis on publications after 1980 was carried out to clarify whether pregnancy rate and litter size may be influenced by energy intake. The studies reviewed indicate that low energy intake compared to high energy intake before mating may impair litter size in gilts and in sows that experienced severe weight loss during lactation. Furthermore, moderate energy intake compared to low energy intake in the first 3 days after mating may reduce litter size in the gilt but not in the sows. Both pregnancy rate and litter size might be influenced by very low energy intake in the first 4 weeks of pregnancy. Based upon studies indicating that low ranking sows may consume considerably less than high ranking sows (e.g., 50-80%) in group-housed systems, it is suggested that the variation in feed intake in a group of restricted fed pregnant female pigs may be large enough to influence pregnancy rate and litter size.     

Factors influencing farmers' responses to welfare legislation: A case study of gestation sow housing in Flanders (Belgium)

In the light of the EU ban on individual confinement of gestating sows which will have to be fully implemented by 2013, a survey was conducted among a representative sample of Flemish pig producers. The questionnaire was sent by post to 250 farmers in 2003 and 352 farmers in 2005 of which 219 and 296, respectively, provided valid responses via telephone. The percentage of respondents housing (some of) their sows in group was 10.5% in 2003 and 16.2% in 2005. These farmers were more likely to have a successor than farmers housing their sows individually. The most common group housing systems were free access stalls (24%) followed by electronic feeding stations (21%), ad libitum feeding (20%), feeding stalls/troughs (18%), and drop/trickle feeding systems (13%). Interval (4%) and electronic feed dispensers (0%) were very rare in Flanders. The main criteria for having chosen a particular group housing system related to sow health and welfare, investment costs and amount of labour. The relative importance of economic reasons has increased over time. Users were generally rather satisfied with their group housing system. Farmers using group housing for all their sows were more satisfied than farmers using both group and individual housing. Users of ad libitum feeding systems (and feeding stalls/troughs) were more satisfied than users of electronic feeding stations. A minority of respondents was planning to change to group housing within two years time (4.1% in 2003 and 7.4% in 2005). These tended to be young farmers with a large sow herd and 58% reported to opt for free access stalls. The main reason why the remaining respondents were not planning to change to group housing yet is that they will stop farming activities before 2013. This reason was particularly important for older small-scale farmers without a successor. In contrast, the lack of financial resources and security was particularly important for young farmers of a large sow herd with a likely successor. An increasing group of farmers (often without a successor) reported to delay changing to group housing because they consider individual housing more profitable. These results show that, in Flanders, the conversion to group housing is taking place slowly, that the reasons for not converting yet vary according to the farmers' age, the likelihood of a successor and herd size, and that there are differences between operational group housing systems concerning herd size, age of the system, sow management and user satisfaction.     

Clinical study results of the embryonic development in gilts and brooding performance of gilts and sows after HCG treatment on the 11th day of pregnancy

Forty-four pregnant gilts were slaughtered on the 32nd and 33rd days of pregnancy, after 30 of them had received 100 or 400 IU of HCG on the eleventh day of pregnancy. Both doses had resulted in higher number of living embryos. Embryo survival rates of treated sows were up to 14.9 percent higher than those of untreated animals. Higher numbers of embryos had no adverse effect on their mass development. Fertility was measured of 77 HCG-treated and untreated gilts as well as of 54 adult sows. The number of non-pregnant sows which returned to oestrus was higher in the group of gilts and adult sows which had received treatment. The number of pregnant animals in the treated adult sow group was seven percent higher than that in the control group. Increased litter sizes were additionally recordable from those gilts and adult sows that had received HCG injections. Yet, those higher litter sizes were associated with lower weight of live-born piglets. In further studies more attention should be given to possible stimulation of LH secretion in early gravidity.     

Well-being in Pregnant Sows: Confinement versus Group Housing with Electronic Sow Feeding

Abstract

Indicators of stress, behaviour in the pen, and lesions of the integument were used as indicators of sow well-being in a comparison of group housing with electronic sow feeding [GH] and confinement in gestation crates [C] in experiment 1, which included 2 × 4 groups of 20–25 sows. Effects of earlier experience with a gestation system on the indicators of stress was investigated in experiment 2, which included 2 × 3 groups of 20–25 sows. Reaction in a novelty test and reactivity in plasma Cortisol to the procedure of blood sampling were used as indicators of stress. Behaviour in the pen as well as lesions of the integument revealed that both gestation systems were suboptimal in some manner. However, following acclimatization for 1–2 weeks, young GH sows experienced less stress than young C sows as measured by reduced fear in the novelty test. In experiment 2 this interpretation was further supported by lower reactivity in plasma Cortisol. It was concluded that sow well-being was higher for the majority of the gestation period in young group-housed animals. Thus, in spite of the inadequate feeding method, well-being of sows may be improved in group housing systems with electronic sow feeding if the system is well functioning with low levels of aggression and vulva bites. One of the major determinants of vulva biting is suggested to be the mechanism of gate control.     

Reproductive performance of sows supplemented with dietary L-carnitine over three reproductive cycles.

The effect of L-carnitine supplementation during pregnancy and lactation on the reproductive performance of sows was studied in two separate trials over three reproductive cycles. Both trials were identical in design and conduct but were performed with different animals. The trials comprised of a total of 127 sows (trial 1) and 100 sows (trial 2) which were divided into control and treatment groups. All animals were fed individually and received basic feed mixtures with low native carnitine concentrations. The rations of the sows in the treated group were supplemented with 125 mg L-carnitine per head and day during pregnancy and 250 mg L-carnitine per head and day during lactation. The animals of the control group received identical feed mixtures in identical amounts, but without the L-carnitine supplement. In the first trial, 212 litters were produced and evaluated for number and body weight of the animals, in the second trial, 173 litters were produced. L-carnitine supplementation significantly increased body weight gains of the sows between day 1 and day 85 of weaning. The number of born piglets, stillborn piglets and piglets fit for rearing was not influenced by dietary L-carnitine supplementation. However, L-carnitine supplementation significantly increased the weights of piglets and litters at birth, weight gains of litters during suckling and weights of litters at weaning. These effects of L-carnitine were seen in both trials; they were independent of the age of the sows and remained over three reproductive cycles in which the sows where continuously treated with L-carnitine. Overall, the study shows that dietary supplementation with L-carnitine during pregnancy and lactation improves the reproductive performance of sows over several reproductive cycles, independent of the age of the sows.     

The role of behavioral science in animal welfare, in teaching and practical application: behavior of swine

The regulation for the keeping of pigs from 1988 acknowledges in principle only results of research, induced by long term problems in pig husbandry. Therefore it is only relevant for problems, that became apparent at least ten years earlier. Group housing for sows is not taken into consideration in the regulation. However, in the near future veterinarians will be expected to produce an opinion about the welfare of sows kept in group housing systems. In the houses for pregnant sows and in the ones for farrowing sows and for sows with piglets, problems can be expected resulting from group housing. Practice is not always according the nice theory, telling us, that sows want a place on their own for farrowing. Thus it can be difficult to end up with one sow in one farrowing nest. If piglets leave the farrowing nest to early, they will not be able to recognize their own sow amidst the group of others. This results in "multisuckling", with its large number of runts. However, group housing expects every piglet to stay with its own sow. In considering the welfare of sows kept in group housing systems a veterinarian will have to ask himself again and again, whether the sows are able to cope with the presented situation. The same counts for the piglets.     

Social rank of pregnant sows affects their body weight gain and behavior and performance of the offspring

Previous studies on group housing of pregnant sows have mainly focused on reproduction, but we hypothesized that the social rank of pregnant sows housed in groups could also affect birth weight, growth, and behavior of their offspring. Therefore, in the present study, pregnant gilts and sows were housed in 15 different groups (n = 7 to 14 animals per group) from 4 d after AI until 1 wk before the expected farrowing date. All groups were fed by an electronically controlled sow feeding system that registered, on a 24-h basis, the time of first visit, number of feeding and non-feeding visits, and number of times succeeding another sow within 2 s. Only in the first 6 groups (n = 57 animals), agonistic interactions were observed continuously. The percentage of agonistic interactions won was highly correlated (r(s) = 0.90, P < 0.001) with the percentage of displacement success (DS) at the feeding station, which was calculated as: [the number of times succeeding another sow within 2 s/(the number of times succeeded by another sow within 2 s + the number of times succeeding another sow within 2 s)] x 100. This allowed us to classify all sows (n = 166) according to their DS: high-social ranking (HSR) sows had a DS >50% (n = 62) and low-social ranking (LSR) sows a DS <50% (n = 104). Body weights before AI did not differ between HSR and LSR sows, but HSR sows gained more BW during gestation, and lost more BW and back-fat during lactation (P < 0.001). Maternal salivary cortisol concentrations at 2, 7, and 13 wk after AI did not differ between HSR and LSR sows, nor did gestation length, litter size, or percentage of live born piglets. During a novel object (NO) test at 3 wk of age, HSR offspring moved and vocalized more than LSR offspring (P < 0.05). In addition, the latency time to touch the NO was shorter in HSR offspring (P < 0.05), and HSR males spent more time near the NO than LSR males (P < 0.01). At weaning, HSR offspring weighed more than LSR offspring (P < 0.05), and at slaughter HSR offspring had more lean meat than LSR offspring (P < 0.05). Results indicate that the social rank of the sow during gestation affects her own BW gain and loss as well as the growth and behavior of her offspring. Pig breeders that apply group housing for pregnant sows should pay attention to reducing competition around the feeding area, which may reduce aggression among the sows and minimize differences between HSR and LSR sows.     

妊娠母猪群养模式成功与否的探讨

我国很多养猪场的妊娠母猪采取群养方式,群养模式具有节约空间和提高福利水平的优点,但与单体栏饲养模式相比,人们可能还会考虑群养模式下的妊娠母猪生产性能、争斗和健康等方面,此外,我们也发现在母猪生产力、肢蹄问题、和福利等方面得出决定性结论的文献也比较少,因此,本文主要描述了群养模式下不同给料方式、地面质量和垫料等因素对妊娠母猪行为、生理、损伤、免疫和繁殖性能等方面的影响并结合我们多年的生产实践经验,提出了一系列实践性的建议,目的是提高当前我国群养模式下的妊娠母猪生产力和福利水平。     

Effects of Group Size during Pregnancy and Introduction Method on Behaviour of Relevance for Piglet Performance in Multi-suckling Pens

The effects of group size during pregnancy (12 or 24 sows) and introduction methods on behaviour in multi-suckling pens were studied. The introduction methods were: A) (control) all sows and piglets were moved simultaneously to the multi-suckling pen on day 11 after farrowing; B) sows and piglets were moved simultaneously on day 14 after farrowing; C) sows were moved simultaneously and, two hours later, all piglets were moved simultaneously on day 11 after farrowing; D) each sow and her litter were moved separately at three-hours intervals on day 11 after farrowing. The effects of group size during pregnancy interacted with the effects of introduction method. When housed in groups of 12 during pregnancy, treatments B-D resulted in more initiated, but fewer successful nursings compared to A. However, when sows had been housed in groups of 24 during pregnancy, increased age (B) resulted in a decreased number of initiated nursings compared to A, but an increased nursing synchrony. The results indicate that it is possible to affect behaviour in multi-suckling pens through the social environment during pregnancy and by the choice of introduction method.     

Effect of L-carnitine supplementation on performance parameters in gilts and sows

The effect of L-carnitine supplementation during pregnancy and lactation on performance parameters of sows was studied. The trial comprised a total of 127 sows (40 gilts, 87 mature sows) which were divided into a control and a treatment group. All animals were fed individually and received basic feed mixtures for pregnancy and lactation with low carnitine concentrations (gestation diet: 4.7 mg/kg feed, lactation diet: 12.5 mg/kg feed). The rations of the sows in the treated group were supplemented with 125 mg L -carnitine per head and day during pregnancy and 250 mg L -carnitine per head and day during lactation. The animals of the control group received identical feed mixtures in identical amounts, but without the L -carnitine supplement. L -carnitine supplementation resulted in higher sow liveweight gains between day 1 and day 85 of pregnancy. The number of piglets per litter and the number born alive did not differ between the control sows and those treated with L -carnitine. However, the L -carnitine-supplemented sows produced only half as many non-viable piglets as the control animals. Moreover, litter weight and mean birth weight of piglets from L -carnitine-treated sows were higher than in the control sows. This effect was more marked in gilts (+8% higher litter weight, +9% higher piglet weight) than in sows (+7% and +6%, respectively). Piglets from sows whose ration was supplemented with L -carnitine showed higher liveweight gains during the suckling period (+12% for gilts, +4% for sows), which is why litter weights post weaning were also higher among the sows treated with L -carnitine than in the control sows (+14% for gilts, +10% for sows). Overall, the study shows that dietary supplementation with L -carnitine during pregnancy and lactation improves the reproductive performance of sows.     

母猪肠道微生态与繁殖生理研究进展

动物胃肠道微生物具有很强的代谢活性,对宿主的营养物质利用和生理代谢功能具有重要调控作用,可影响动物的生产性能和机体健康。为了适应胎儿的生长发育,妊娠期间母体的肠道菌群组成和代谢活性发生显著变化。笔者结合自己近年来的研究成果,对国内外母猪肠道微生态与繁殖生理方面取得的研究进展进行综述,以期为研发提高母猪繁殖性能的调控技术提供思路。     

A long term study of the health status and performance of sows on different feed allowances during late pregnancy. I. Clinical observations, with special reference to agalactia post partum

Thirty nine pairs of full sibs were investigated over 6 parities in a long term study on the effects of late pregnancy feed allowance on the occurrence of agalactia post partum and on the performance of sows and piglets. A careful examination of all sows with a rectal temperature exceeding 39.5 degrees C was performed by a veterinarian within the first 48 h after farrowing. Milk-samples were taken from sows with elevated rectal temperatures and showing clinical symptoms of agalactia. During the last 15 days of gestation the sows in the control group were fed 3.4 kg daily and the sows in the experimental group 1.0 kg daily of a commercial type of diet. In 26.6% of the farrowings in the control group the sows were agalactic whereas the corresponding figure in the experimental group was 14.4%. On clinical examination udder changes were observed in a majority of the diseased sows in both groups. However, the agalactic sows in the control group were generally more affected, with lower water and feed consumption than in the experimental group. No effects of age of the sow (parity number) or length of the gestation period on the incidence of agalactia were demonstrated. The rectal temperature of agalactic sows was significantly higher than in the healthy sows already 1 day before farrowing. The agalactic sows farrowed a larger number of stillborn piglets, which indicates an early establishment of the disease. The number of weaned piglets at 6 weeks did not differ between agalactic and healthy animals. The interval from weaning to first oestrus was not influenced by agalactia in the preceding lactation.