Epidemiological studies of piglet diarrhoea in intensively managed Danish sow herds. II. Post-weaning diarrhoea

This study comprised 48,931 litters in 89 sow herds. During the study (1976-82) weaning age decreased from approx. 42 days to approx. 30 days. The mean incidence of post-weaning diarrhoea was 6.0% of litters weaned, with little variation by year but with considerable variation among herds. Within the individual herd increased incidence occurred over limited periods, probably associated with specific infections. Litters with diarrhoea during the suckling period had increased risk of post-weaning diarrhoea. The incidence of post-weaning diarrhoea increased with litter size at weaning. Thus, a litter of 11-12 piglets at weaning had 1.2 times higher risk than litters with 8-10 piglets. In contrast to pre-weaning diarrhoea, there was no association between parity of the sow and diarrhoea in the litter after weaning. Litters weaned below 2 weeks of age had a 2-fold risk of developing diarrhoea after weaning and a 2.4-fold higher mortality rate than did litters weaned at 6-7 weeks. Similarly, litters weaned at an individual piglet weight below 3 kg bodyweight had a 3-fold higher risk of developing diarrhoea after weaning and a 5-fold higher mortality rate than did pigs from litters weaned at a bodyweight of 7-8 kg. The incidence of post-weaning diarrhoea decreased with increasing herd size. Piglets from litters with post-weaning diarrhoea had reduced weight gains after weaning and were 2.3 days older at 25 kg bodyweight than piglets from non-diarrhoeic litters. Likewise, diarrhoea after weaning was associated with an increased incidence of diseases of the skin and respiratory tract. Thus the risk of contracting respiratory disease was 4 times greater in diarrhoeic litters.     

Influence of supplementary iron in late pregnancy on the performance of sows and litters

On eight farms alternate sows and gilts within three weeks of their expected farrowing date were injected intramuscularly in the neck with 8 ml of an iron (gleptoferron) preparation containing 200 mg iron/ml, or kept as uninjected controls. Data from 513 iron-injected and 488 control animals were used in the analysis of results. Small, but not statistically significant, improvements were observed in the numbers of piglets born alive and dead/litter, the birth weights and weaning weights at three weeks, the numbers of piglets fostered on and off/litter, piglet mortality, the number weaned/litter and the weaning to service interval. The condition scores of the iron-injected sows were marginally below those of the controls at weaning, but their condition scores at farrowing had also been slightly below those of the controls. A summation of these trends would suggest an overall benefit of approximately 0.45 pigs/sow/year in favour of the iron-injected sows.     

Maternal behaviour and performance in first-parity outdoor sows

When sows and their litters are kept outdoors, much of the responsibility for the litter is shifted from the herdsman to the sow compared to when the sows are kept indoors. Therefore, the maternal ability, including maternal behaviour, is believed to be important in outdoor piglet production. The aim of this study was to describe maternal traits in conventionally bred first-parity sows kept outdoors. Nursing behaviour, sow activity, sow body reserves, litter size and piglet growth were studied in 40 first-parity sows during a seven week long lactation. The sows were kept in groups outdoors. Sow activity (lying down or active) and nursing behaviour (nursing frequency, nursing duration and nursing terminator) were recorded on videotapes at four days post partum (pp) and directly observed at four and six weeks pp. Cross suckling was observed at four and six weeks pp. Sows were weighed and measured for backfat depth five days before farrowing, two weeks pp and at weaning seven weeks pp. Piglets were weighed at four days pp, at two weeks pp and at weaning. We concluded that sow nursing behaviour and activity are individual characteristics repeatable within sows' late lactation. Less active sows are more available for suckling. Light and thin sows have an earlier and more progressed weaning process than heavier, fatter sows. A significant positive relation was found between sow appetite in early lactation and piglet growth until weaning. Sow nursing behaviour is not important for piglet growth when sows and piglets are held in groups, piglets have access to sow feed and piglets are weaned as late as at seven weeks of age.     

Socializing piglets before weaning: effects on behavior of lactating sows, pre- and postweaning behavior, and performance of piglets

This study evaluated how socializing piglets before weaning affects behavior of lactating sows and the pre- and postweaning behavior and performance of piglets. Two farrowing rooms, each with 6 pens, and 1 nursery with 4 pens were used. In total, data were obtained from 24 sows and their litters. In each farrowing room, the solid barriers between 3 farrowing pens were removed on d 12 after farrowing, and the sows remained confined in their crates (experimental group). In the other 3 farrowing pens of each farrowing room, sows and their litters were kept under conventional conditions until weaning (control group). All piglets were weaned 28 d after birth. After weaning, piglets from each group remained together in 1 pen of the nursery. The behavior of sows (lying, standing, sitting, nursing) and piglets (lying, active, suckling) in the farrowing rooms was observed for 24 h before and for 48 h after removal of the barriers between the pens. In addition, behavior (active, lying, feeding, agonistic behavior) of piglets was observed in the nursery during the initial 48-h period after weaning. Each piglet was weighed on d 5, 12, and 28 after birth and thereafter weekly until the fifth week of rearing. In the farrowing room, mixing of litters did not influence behavior of piglets and sows. Preweaning weight gain of the piglets did not differ (P = 0.60) between the treatments. In the initial 48 h after weaning, less agonistic behavior (P < 0.001) was observed in piglets belonging to the experimental group. During 5 wk of rearing, piglets in the experimental group gained more weight compared with the control group (P = 0.05). The advantage shown by the experimental group became especially conspicuous in the first week after weaning (P = 0.05). By socializing unfamiliar piglets before weaning, stress due to mixing could at least be distanced in time from the other burdens of weaning, thereby improving performance.     

Factors affecting length of productive life in Swedish commercial sows

The objective of this study was to investigate factors that might influence the length of productive life in Swedish crossbred (Landrace x Yorkshire) sows. The data set consisted of 20,310 sows farrowing between 2001 and 2004 in 21 commercial piglet-producing herds. Productive life (PL) was defined as the number of days between first farrowing and removal or termination of data collection. In addition to the overall risk analysis of PL, another 4 longevity traits were analyzed (competing risk analyses): reproductive disorder-determined length of PL (RPL), udder problem-determined length of PL (UPL), lameness-determined length of PL (LPL), and mortality-determined length of PL (MPL). Analyses were performed by using survival analysis, applying a Weibull model with 6 time-dependent and 1 time-independent variable (age at first farrowing). The factor with the largest contribution to the likelihood function for PL was days after farrowing, followed by parity, the herd x year combination, the total number of piglets born, days between weaning and next farrowing, farrowing month, and age at first farrowing. For all 4 competing risk traits, the factors contributing most to the likelihood function were days after farrowing, the herd x year combination, and parity, with a varied order between traits. The hazard for removal was greatest 30 to 40 d after farrowing (after weaning) for PL, UPL, and LPL (P < 0.001). However, for MPL the hazard was greatest just after farrowing (0 to 10 d), and for RPL the hazard peaked at 70 to 100 d after farrowing. The hazard for removal was, compared with parity 1, less in parities 2 to 7 and greater from parity 8 for PL (P < 0.001). The hazard was greatest in parity 1 (P < 0.01) for RPL, UPL, and LPL, whereas for MPL the hazard increased with greater parity number and was markedly greater from parity 9 (P < 0.001). Sows with litters of 9 piglets or less had a greater hazard for removal than sows with litters of 12 to 13 piglets (P < 0.001). Intervals between 120 and 122 d from weaning to the next farrowing showed the lowest hazard for removal (P < 0.001). The influence of farrowing month displayed no clear pattern for PL. Sows of 14 mo or older at their first farrowing had a 20% greater hazard for removal than younger sows (P < 0.001). The hazard for removal was greater for smaller litters in all parities but was more accentuated in greater parities. Overall, days after farrowing was the main risk factor for sow removal. Removal hazard was greatest shortly after weaning, and this peak increased with greater parity number.     

Within-litter variation of birth weight in hyperprolific Czech Large White sows and its relation to litter size traits, stillborn piglets and losses until weaning

Data from about 2900 litters (approximately 40,000 piglets) originating from 1063 Czech Large White hyperprolific sows were analyzed. The phenotypic and genetic relations between litter size traits, piglet mortality during farrowing and from birth to weaning and several statistics referring to the distribution of the birth weight within litter were analyzed. All genetic parameters were estimated from multi-trait animal models including the following factors: mating type (natural service or insemination), parity, linear and quadratic regression on age at first farrowing (1st litter) or farrowing interval (2nd and subsequent litters), herd-year-season effect and additive-genetic effect of the sow. The phenotypic correlations of the mean birth weight with the total number of piglets born and piglets born alive were − 0.30. Traits describing the variability of the birth weight within litter (range, variance, standard deviation, coefficient of variation) were mostly positively correlated with litter size. A statistically significant phenotypic correlation (− 0.09 to − 0.15) between mean birth weight and losses at birth and from birth to weaning was found. The heritability for the number of piglets born, piglets born alive and piglets weaned was around 0.15. The number of stillborn piglets had only a very low heritability less than 0.05, whereas the heritability for losses from birth to weaning was 0.13. The heritabilities of the mean, minimal and maximal birth weight were 0.16, 0.10 and 0.10, respectively. The heritability for all statistics and measures referring to the variability of the birth weight within litter was very low and did never exceed the value of 0.05. An increase in litter size was shown to be genetically connected with a decrease in the mean piglet birth weight and an increase in the within-litter variability of birth weight. Selection on litter size should be accompanied by selection on mortality traits and/or birth-weight traits. Losses from birth to weaning and the minimal birth weight in the litter were proposed as potential traits for a selection against piglet mortality.     

Iron deficiency in outdoor pig production

It has been claimed that outdoor-reared suckling piglets do not need iron supplementation. According to practical experience, outdoor-reared and non-iron-supplemented piglets show a lower performance in comparison with their iron-supplemented counterparts. The purpose of the present study was to determine the effect of iron supplementation on outdoor-reared suckling piglets. In a large Hungarian outdoor pig production unit, 4691 piglets were assigned to one of two treatment groups. Piglets in group 1 (n = 2344): received no iron supplementation, whereas piglets in group 2 (n = 2347) were intramuscularly injected in the neck on day 3 post-partum with 1.5 ml of Ferriphor 10% solution (TAD Pharmaceutical GmbH, Bremerhaven, Germany). Animal weights, morbidity, haemoglobin concentration and mortality were recorded and analysed. At weaning the iron-injected piglets were significantly (P < 0.05) heavier. The iron-supplemented piglets also revealed significantly (P < 0.01) less pre-weaning morbidity and mortality and higher (P < 0.01) blood haemoglobin concentration compared with the non-injected ones. This study suggests that in order to prevent pre-weaning losses and support piglet health and weight performance, iron supplementation should be administered to piglets in outdoor pig production units.     

Postweaning growth check in pigs is markedly reduced by intermittent suckling and extended lactation

The objective of this study was to determine whether intermittent suckling (IS) combined with an extended lactation can reduce postweaning growth check in pigs. Three weaning regimens [conventional weaning (CW), IS with 6-h separation intervals (IS6), and IS with 12-h separation intervals (IS12)] were compared. In CW (n = 17 litters), litters had continuous access to the sow until weaning (d 21, d 0 = farrowing). In IS6 and IS12, litters were separated from the sow for 12 h/d, beginning at d 14 and lasting until weaning (d 41 to 45). Litters were with the sow from 1400 to 2000 and from 0200 to 0800 (IS6, n = 14) or between 2000 and 0800 (IS12, n = 14). Litter size was standardized within 2 d after farrowing by crossfostering, resulting in an average litter size of 10.9 +/- 1.8 piglets. Piglets had ad libitum access to creep feed from d 7 onward. One week after the onset of IS (d 20), creep feed intake was increased in litters from both IS groups compared with CW litters (P < 0.05). Both IS groups consumed considerable amounts of creep feed before weaning (d 41 to 45). Total feed intake before weaning was greater (P = 0.004) in IS12 (3,808 +/- 469 g/piglet) than in IS6 (2,717 +/- 404 g/piglet). In comparison, CW litters consumed 18 +/- 9 g/piglet before weaning (d 21). Irrespective of weaning regimen, total feed intake of litters before weaning was highly correlated with post-weaning feed intake (P < 0.001). Furthermore, in all treatment groups, total preweaning feed intake was correlated with postweaning growth (P < 0.10). Irrespective of treatment, piglets suckling anterior teats grew faster than piglets suckling middle or posterior teats during the first 2 wk of lactation. Body weights at the end of the experiment (d 55) were similar among weaning regimens. Onset of IS induced a growth check in both IS groups (34% for IS12 and 22% for IS6). Only a mild growth check was observed after weaning of IS litters (14% for both IS groups). However, a serious growth check (98%) was observed after weaning of CW litters. Results of the current study indicate that IS stimulated feed intake during lactation, providing a more gradual transition to weaning. Because the IS6 regimen did not prevent the growth check after the onset of IS and is rather laborious, we suggest that IS12 might be preferable for a practical implementation of IS.     

FACTORS CONTRIBUTING TO POSTWEANING DIARRHOEA IN A LARGE INTENSIVE PIGGERY

Some aspects of postweaning diarrhoea (PWD) in a piggery during the first week after early weaning were investigated. A haemolytic enterotoxigenic strain of E. coli (0149: K88: H10) was regularly recovered from piglets with PWD while rotavirus was demonstrated on a number of occasions. Prior to weaning piglets were either free of, or shed very few, haemolytic E. coli in their faeces. However, all piglets were excreting haemolytic E. coli between 5 and 7 days after weaning. The role of rotavirus in PWD was unclear. There appeared to be a direct relationship between serum antibodies to rotavirus in the sow at farrowing and those of the piglets soon after birth. The decline of maternal neutralising antibody to rotavirus coincided with the immediate postweaning period (3 to 5 weeks after birth). This was followed by an increase in antibody levels, 5 to 8 weeks after birth. There was no significant difference in the growth rate between affected and unaffected piglets over a period of 120 days. Medication of water during the first week after weaning had no significant effect on the incidence of PWD in the herd. A change in both the weaner diet and the weaning procedure reduced piglet mortality associated with PWD by more than half.     

Factors affecting piglet mortality in loose farrowing systems on commercial farms

Crating sows in farrowing systems greatly restricts their normal behaviour (e.g. movement, nest-building, leaving the nest site for defecation), which is usually justified by the assumption that piglet mortality is higher with loose-housed sows. Based on experiments showing that this is not the case, farrowing crates were banned in Switzerland in 1997, with a 10-year transitional period. Since then, many farms have introduced loose farrowing systems, enabling an analysis of risk factors for piglet mortality in crateless farrowing systems based on a large sample size. Data from a Swiss sow recording scheme (UFA2000) were analysed using generalised linear mixed-effects models with an underlying Poisson distribution. Average total piglet mortality for the years 2002 and 2003 on 99 farms (N = 12457 litters) with loose farrowing systems amounted to 1.36 liveborn piglets per litter. The number of crushed piglets was 0.64 piglets per litter, whereas the number of piglets that died for other reasons was 0.72 piglets per litter.Herd size, pen size, possibility of confinement of the sow, presence of piglet protection bars and year of data collection did not significantly influence total piglet losses, losses due to crushing and losses due to reasons other than crushing. With greater litter size at birth, significantly more losses occurred due to all reasons (total, crushed, others). Total piglet mortality and losses for reasons other than crushing were significantly higher in older sows. Losses were therefore mainly attributable to sow-related characteristics rather than to the design of the farrowing pen.     

A cohort study of preweaning piglet mortality and farrowing accommodation on 112 commercial pig farms in England

A cohort study was carried out on 112 breeding pig farms in England to investigate the impact of type of farrowing accommodation on preweaning mortality in piglets. Four types of farrowing accommodation were studied; farrowing crates, indoor loose pens, crate/loose systems (where the sow was restrained in a crate during birth and the first days of lactation before being moved to a loose pen) and outdoor farrowing in arcs in paddocks. Four estimates of preweaning mortality were collected: an oral estimate from the farmer before the visit, an estimate from the 6-month rolling average from computer records, records from 20 litters observed when the farm was visited and prospective records collected from 20 farrowings after the visit. These four estimates were significantly correlated. The prospective records also included a farmer reported date and cause of death. From the prospective data there were 25,031 piglets from 2143 litters from 112 farms, 6.5% of piglets were stillborn while live born preweaning mortality was 12%. Mixed effect discrete time survival, binomial and competing risk, models were used to investigate the association between preweaning mortality and farrowing accommodation, controlling for sow parity, litter size and number of piglets stillborn and fostered. There was a reduced risk of stillbirths in outdoor farrowing systems compared with crated systems. Farmers reported that crushing of healthy piglets was the most frequent cause of death accounting for 55% of live born preweaning mortality. There was no significant difference in mortality in live born piglets by farrowing system. There was a significantly higher risk of farmer reported crushing of healthy live born piglets in outdoor arcs compared with piglets reared with sows in farrowing crates and a significantly reduced risk of death from causes other than crushing in piglets reared outdoors or in crate/loose systems compared with piglets reared in crated systems. We conclude that, in the farms in this study, farrowing crates reduced the risk of preweaning live born mortality attributable to crushing but piglets in this system were at increased risk of death from other causes. Consequently crates had no significant effect on overall preweaning mortality percentage. In all four commercial production systems; outdoor, farrowing crates, crate/loose farrowing systems and indoor loose housed systems, there were similar levels of mortality.     

Influence of tooth resection in piglets on welfare and performance

In six commercial pig farms, we compared the effects of two methods of tooth resection (tooth clipping with pliers and tooth grinding with a rotating grindstone) on teeth themselves, on skin lesions of piglets and of sow udders as well as on litter growth and survival. An intact group was included for control. Treatments were balanced within herds with sows assigned to one of the three experimental treatments. Observations were from 107 sows and their litters (n = 35 or 36 litters/group) at farrowing (day 0) and approximately 8, 15 and 27 days later. Tooth resection was done within 24 h of birth after cross-fostering. Data concerning sows' lesions were analyzed on a farm basis and those concerning piglets' mortality, growth and skin lesions were analyzed on a litter basis. Frequency and severity of udder lesions differed between treatments at farrowing and on day 8; differences depended on the location of the teats (front, median or rear). Litter size and liveweight of piglets on day 0 (11.9+/-0.1 pigs, 1.51+/-0.03 kg) and on day 27 (10.8+/-0.1 pigs, 8.08+/-0.10 kg) were similar in the three groups (mean+/-S.E.M., n = 107). Skin lesions on piglets were more frequent and/or severe in intact than in clipped piglets on days 8 and 27, whereas ground piglets had intermediate results. Because the length of the teeth was similar after clipping and grinding (P > 0.1), tooth shortening itself does not explain the differences between treatments. Overall, tooth resection had very little effect on sow mammary injuries and litter performance. It might reduce skin damage to piglets (especially, when it is performed by clipping) but teeth are severely injured.     

Colostrum yield and litter performance in multiparous sows subjected to farrowing induction

The consumption of colostrum at a low level can compromise the survival and growth of piglets. Therefore, this study aimed to evaluate the effect of farrowing induction on colostrum yield, IgG concentration and the survival and performance of piglets until the weaning. Sows of parity 3 to 7 were assigned into two groups: Control (n = 48), sows with spontaneous farrowing; and induction (n = 48), sows induced to farrow on day 114 of gestation with a PGF₂ analogue. Colostrum and blood samples were collected from the sows, at farrowing and 24 hr later. Blood samples from the piglets were collected at 24 hr after birth. The performance of the piglets was evaluated in a subsample of 28 litters from each group. All piglets were weighed at 7, 14 and 20 days of age. The farrowing length, the number of piglets born alive, stillborn piglets, weight at birth, litter weight at birth and colostrum yield were not significantly affected (p > .05) by farrowing induction. There was no difference between the groups (p > .05) in the percentage of sows with obstetric interventions. Serum IgG concentration, in both sows and piglets, and colostrum IgG concentration were similar between the groups (p > .05). Furthermore, survival rate, piglet weight and litter weight at 7, 14 and 20 days of age were also similar between the groups (p > .05). Therefore, it can be concluded that the farrowing induction performed on day 114 of gestation does not affect the colostrum yield, the IgG concentration in colostrum and serum of piglets, and the litter performance until the weaning.     

不同断奶日龄仔猪血液中生长相关激素的检测

为探讨断奶日龄对仔猪血液生长相关激素指标的影响,试验从8窝"杜×长×大"仔猪中选取出生日龄相近、初生体重一致的健康仔猪24头,随机分为4个试验组,每个试验组设6个重复,每个重复1头仔猪,4组仔猪分别于14、21、28、35日龄断奶。至42日龄时,所有仔猪宰杀采血,利用放射免疫分析法进行血浆生长激素(GH)、胰岛素(INS)、三碘甲状腺原氨酸(T3)和四碘甲状腺原氨酸(T4)含量检测。结果表明,不同日龄组断奶仔猪血浆GH、T3和T4水平无显著性差异(P0.05);35日龄组断奶仔猪血浆INS含量显著高于14日龄断奶组(P0.05)。结果提示,不同断奶日龄对仔猪生长相关激素无显著影响。     

Natural transmission of group A rotavirus within a pig population

Five litters of piglets born within two days of each other, together with their dams, were investigated for faecal excretion of group A rotavirus antigen from birth to two months old. All the 50 piglets in these litters became infected with the virus between 19 and 35 days old. Rotavirus excretion was first seen in one litter which was housed with other litters not included in this study. Two days later, piglets of the second litter in another farrowing room began to excrete rotavirus, and then infection spread to the other three litters in the same room. Within each of these litters, one or two piglets were infected early and thereafter infection spread to other piglets. It took four to 10 days for rotavirus to infect every piglet within a litter, and 16 days in total before all piglets in the five litters were infected. No rotavirus antigen was demonstrated in faeces from sows during the investigation period.     

互助县现代畜牧业生产发展现状和建议

畜牧业是新农村建设的萤要组成部分,加快农区畜牧业发展对于调整农业产业结构,发展农村经济,增加农民收入,加快新农村建设步伐,实现小康社会具有十分重要的意义。当前,随着社会主义市场经济的深入发展和西部大开发战略的有效实施,互助县畜牧业进入了一个新的发展时期,我们既面临着良好的发展条件和机遇,也面临着新的挑战和问题。为抓住机遇,实现畜牧业发展的新突破,推动新农村建设．提出以下建议和思路,以供参考。     

Bayesian threshold analysis of direct and maternal genetic parameters for piglet mortality at farrowing in Large White, Landrace, and Pietrain populations

A Bayesian threshold model was fitted to analyze the genetic parameters for farrowing mortality at the piglet level in Large White, Landrace, and Pietrain populations. Field data were collected between 1999 and 2006. They were provided by 3 pig selection nucleus farms of a commercial breeding company registered in the Spanish Pig Data Bank (BDporc). Analyses were performed on 3 data sets of Large White (60,535 piglets born from 4,551 litters), Landrace (57,987 piglets from 5,008 litters), and Pietrain (42,707 piglets from 4,328 litters) populations. In the analysis, farrowing mortality was considered as a binary trait at the piglet level and scored as 1 (alive piglet) or 0 (dead piglet) at farrowing or within the first 12 h of life. Each breed was analyzed separately, and operational models included systematic effects (year-season, sex, litter size, and order of parity), direct and maternal additive genetic effects, and common litter effects. Analyses were performed by Bayesian methods using Gibbs sampling. The posterior means of direct heritability were 0.02, 0.06, and 0.10, and the posterior means of maternal heritability were 0.05, 0.13, and 0.06 for Large White, Landrace, and Pietrain populations, respectively. The posterior means of genetic correlation between the direct and maternal genetic effects for Landrace and Pietrain populations were -0.56 and -0.53, and the highest posterior intervals at 95% did not include zero. In contrast, the posterior mean of the genetic correlation between direct and maternal effects was 0.15 in the Large White population, with the null correlation included in the highest posterior interval at 95%. These results suggest that the genetic model of evaluation for the Landrace and Pietrain populations should include direct and maternal genetic effects, whereas farrowing mortality could be considered as a sow trait in the Large White population.     

Reproductive efficiency and incidence of MMA after controlled farrowing using a prostaglandin analogue, cloprostenol

In a herd of sows 106 sows having 4.3 litters on aver., were over a period of 10 weeks treated on Thursdays with 0.175 mg of cloprostenol on the 111th to 114th day of gestation; 93--95% of the sows treated on the 112th and 113th day farrowed within 33 hours after treatment, 73% after treatment on the 111th day (Table I); the mean period of gestation after treatment was 113.4 +/- 0.9 days. 8 sows that only farrowed 2--5 days after the treatment, had on 21 previous farrowings proved to have significantly longer mean periods of gestation, 115.6 days, than the 112 sows in the control group, having 3.6 litters on average, that farrowed in the same period and section of the piggery as the sows treated with cloprostenol. In total 32 weekend-farrowings occurred in the observation period including 7 farrowings after a period of gestation of 110--113 days, 6 cases of unsuccessfully induced parturition and 19 farrowings on the 114th to 119th day that could have been programmed to occur on Fridays; the number of weekend-farrowings, which for this herd in connection with the weaning procedure normally accounted for about 40--45% of farrowings, could thus be reduced to 7% of farrowings (Table II). Cloprostenol treatment on the 111th day resulting in farrowing on the 112th day leads to a significantly higher rate of piglet mortality after 3 weeks compared with the results after farrowing for control sows that farrowed on the 112th day (Table III); this category of control sows had on previous farrowings proved to have a significantly shorter mean period of gestation, 112.7 days, than that of the sows in the cloprostenol group farrowing on the 112th day which had been 114.3 days on previous farrowings. Farrowing and weaning results after induced parturition resulting in farrowing on the 113th to 115th day showed no significant differences from the results for control sows farrowing spontaneously on the 112th to 115th day of gestation. The incidence of MMA (Table II) was not influenced by the cloprostenol treatment, nor by the number of litters, the length of the period of gestation, or by the piling of farrowings on Fridays.     

Effects of toltrazuril on the growth of piglets in herds without clinical isosporosis

Isospora suis is a widely prevalent and economically important parasite. The antiprotozoal compound, toltrazuril, was given as a single treatment to piglets without clinical signs in 10 herds. The daily weight gain (DWG) and mortality between the treatment date and weaning was compared on each herd in 10 treated and 10 control litters. The faeces of control litters were examined for oocyst excretion. In six herds, no oocysts were detected and treatment had no effect on DWG or mortality. In four pig herds, oocysts were detected and toltrazuril treatment significantly improved DWG by 25 g (P=0.003). Mortality rate was not affected. The partial economic benefit of toltrazuril treatment in positive herds was 0.20 euros per piglet. A single toltrazuril treatment of piglets in herds without clinical signs of isosporosis but with oocysts detected significantly improved DWG and was considered economically justified on each farm.     

Effect of rearing environment and age on gut development of piglets at weaning

Outdoor reared pigs are reported to be larger at weaning than indoor reared pigs and respond better to the weaning process. This may be due to enhanced gut development associated with increased size. Eighty sows were allocated to either indoor or outdoor farrowing on the basis of size, parity and past performance. Resulting litters were weaned at either 4 or 6 weeks of age. On days 26 and 40 of age, 40 (10/treatment) and 20 piglets (10/treatment still unweaned) were killed to measure intestinal morphology. Data were analysed as a 2 × 2 factorial using the GLM procedures of Minitab 12.2. Pigs reared outdoors were larger than those reared indoors at both weaning ages, pigs weaned at 6 weeks were heavier than those weaned at 4 weeks, 8.4 versus 7.4 kg at 4 weeks and 12.9 versus 10.5 kg at 6 weeks respectively (± 0.25, P ≤ 0.001). There were no differences in small intestine size relative to body weight due to rearing environment and no differences in gut morphology. When corrected for body weight, 6 week pigs had heavier small intestines than 4 week pigs, 0.39 (± 0.010) versus 0.34 (± 0.007) g/cm length, respectively (P ≤ 0.001). Six week unweaned pigs had similar villus heights to 4 week unweaned pigs but wider villi (P < 0.05) and deeper crypts, for example, at the 25% site crypt depths were 236 and 193 μm (± 7.7/5.5) respectively (P < 0.001). Hence increased piglet size due to outdoor rearing did not advance gut maturation whereas increased piglet size due to age did influence maturation of gut structure.