Evaluation of an atrophic rhinitis vaccine under controlled conditions.

A vaccine containing inactivated cultures of Bordetella bronchiseptica, toxigenic Pasteurella multocida type D and dermonecrotic P multocida type D toxoid in an oil-in-water adjuvant was given to seven sows, with seven others acting as controls. Half the piglets in each litter were exposed intranasally when four days old to B bronchiseptica and when eight days old to toxigenic P multocida type D. There was considerably less sneezing in the litters of the vaccinated sows and when the piglets were 10 weeks old, only 18 per cent had deformed snouts compared with 74 per cent in the litters of the control sows. The average liveweight gain of the piglets born to vaccinated sows was significantly better (P less than 0.05) between two and 10 weeks of age than that of the piglets born to unvaccinated sows, although there were no significant lower respiratory tract lesions in either group. The conchal atrophy scores were significantly lower (P less than 0.001) in the piglets from the vaccinated sows and were negatively correlated (r = -0.37) with increasing liveweight gain. In the liters of the vaccinated sows, P multocida was not isolated from the nasal passages of the in-contact piglets and from only 7 per cent of those deliberately exposed compared with 65 per cent and 79 per cent, respectively, in the litters of the control sows. P multocida was isolated post mortem from the tonsils of 23 per cent of the piglets of vaccinated sows and from 87 per cent of those from unvaccinated sows.     

Reproductive failure associated with porcine parvovirus in an enzootically infected pig herd.

Two outbreaks of porcine parvovirus occurred in a unit of 380 sows, with a subsequent decrease in the size of gilts' litters. Of the 203 gilts and 64 primiparous sows which were seronegative at the time of insemination, 134 gilts and 55 primiparous sows seroconverted during pregnancy. Of the second parity sows nine of 271 were still seronegative at the time of insemination but all nine seroconverted during their third gestation. The gilts that seroconverted during their first pregnancy produced on average 0.9 fewer live piglets than the gilts that did not seroconvert. Second litter sows which seroconverted produced 0.3 fewer piglets than those which did not seroconvert. There were no significant differences between sows which seroconverted or did not seroconvert in the numbers of returns to service, or in the percentages of piglets which were born dead or died before weaning.     

A reduction in litter size on an ontario Swine farm

In a 200 sow herd, the litter size fell from an average of 10.5 pigs born alive per litter from January to June, to an average of 9.2 for the remainder of the year. Management changes during the first part of the year resulted in half the sows weaning litters at three weeks of age and half the sows weaning at four weeks of age instead of at six weeks as was previously done. The subsequent litter size was 9.3 pigs born alive per litter for three-week weaned sows compared to 10.0 for four-week weaning. The management of gilt breeding was also altered by the necessity to breed groups of 12 gilts in one-week periods of time and therefore a higher proportion of gilts may have been mated on their first estrus instead of their second or third estrus as had been the case. The difference in litter size of first parity sows between the first six months and the second six months was 1.1 pigs. Parvovirus infection may have been a factor contributing to the reduction in litter size amongst first parity sows; two groups of first parity sows experienced an increase in mummified piglets, a reduced far rowing rate, and smaller litter size. However, no attempt was made at diagnosing an infectious agent. Parity distribution remained relatively unchanged during the year and was not associated with the drop in litter size.     

Timing and causes of piglet mortality in alternative and conventional farrowing systems

The causes and timing of piglet mortality were studied in different farrowing systems. In the first experiment 198 litters were recorded in three systems, two of which allowed the sows to move freely, and the third restricted them in conventional crates. More piglets were weaned from the conventional crates than from the open systems and they grew more quickly. More than half the liveborn mortality occurred during the first four days after parturition. In the open systems, 17 per cent and 14 per cent of the piglets born alive were crushed, compared with only 8 per cent in the crates. In the second experiment, 29 sows and litters were studied in detail in a communal pen system during the first seven days of lactation. Three-quarters of the liveborn mortality was due to crushing. The total number of piglets dying per litter, including stillbirths, was significantly associated with the total litter size and the sow's parity. The percentage liveborn mortality was significantly associated with the parity and body length of the sows and with the within-litter variation in the birth weight of the piglets. Individual birth weight was closely associated with percentage survival. Only 28 per cent of piglets weighing less than 1.1 kg at birth survived to seven days.     

Control of fertility outcome in artificially inseminated gilts and old sows. 2: Addition of oxytocin to boar semen. Its effect on length of insemination, pregnancy rate and litter size]

Toleration-oriented insemination was applied to 1,373 oestrous sows that had undergone bio-engineering treatment, with two insemination portions having been used for each oestrous. Five International Units of oxytocin were added immediately before insemination proper to the semen applied to 315 gilts and 377 old sows. The control group included 296 gilts and 385 old sows inseminated in parallel. Semen intake, on average, was complete between four and eight minutes with the majority of gilts and between four and seven minutes with most of the old sows, but no evidence was obtained as to any action of the oxytoxin upon intake intensity. The treated gilts were superior to the controls by 6.3 per cent in pregnancy rate and by 56 born piglets to each 100 first inseminations. Superiority, consequently, was significant. In both gilts and old sows added oxytocin prolonged insemination by more than five minutes and gave clearly better fertility results.     

Epidemiological studies of piglet diarrhoea in intensively managed Danish sow herds. I. Pre-weaning diarrhoea

The study comprised 70,796 litters in 104 sow herds, observed from 1976 through 1982. Weaning age decreased from approx. 42 days to approx. 30 days during the observation period. Diseases and symptoms were recorded together with production parameters (feeding, barn construction, economic returns etc.). The mean incidence rate of pre-weaning diarrhoea was 6.8% of litters, with considerable inter-herd differences (incidence rates from 0 to approx. 50%). There was a slight increase in incidence during the autumn (August through October). Incidence rates increased with litter size, with a peak incidence in litters of 11-13 piglets, and decreased with increasing parity of the sow. There was a positive association between occurrence of arthritis and pre-weaning diarrhoea in the litters, and litters from sows with post parturient disease (MMA complex) had 1.8 times higher risk of getting diarrhoea than litters from healthy sows. No important differences among breeds were found. Small herds (less than 200 farrowings per year) had higher incidence rates than large herds (400-499 farrowings per year). Herds with a gilt proportion above 30% had an incidence rate of 12.3%, i.e. nearly twice as high as the overall mean (6.8%). There was a trend towards a higher incidence rate in litters kept in traditional pens (i.e. large pens with solid floor and loose sows) than in intensive pens (i.e. small pens with slatted flooring and tethered sows). The overall pre-weaning mortality rate was 16.2% of pigs born, half of which was due to stillbirths (6.3%) and overlaid piglets (2.2%). In litters with pre-weaning diarrhoea, the mortality rate was 19%, compared to 13% in litters without occurrence of diarrhoea. This difference accounts for an excess loss of 0.6 piglets from birth to weaning in diarrhoeic vs. non-diarrhoeic litters. Piglets from litters with pre-weaning diarrhoea had reduced weight gain. Thus, on the average, they were 2.2 days older at 25 kg bodyweight and weighed 0.4 kg less at 30 days than piglets from non-diarrhoeic litters. Also, litters with pre-weaning diarrhoea had a significantly increased risk of post-weaning diarrhoea. The present information forms a basis for defining acceptable disease thresholds in suckling litters in intensively managed herds.     

Patterns of preweaning diarrhea in piglets on a central California ranch.

To determine risk factors for development of diarrhea in litters of preweaned piglets, data were analyzed from records of 4,397 litters of swine farrowed on a central California ranch 1978-1982. Sixty-four percent of litters were treated for diarrhea. Statistical analysis by multiple logistic regression showed that litters born to young sows (parity less than or equal to 2) were 1.7 times more likely to develop diarrhea before weaning than were litters born to older sows (parity greater than or equal to 3) and that litters born on one end of farrowing barns were 1.3 times more likely to develop diarrhea than were litters born in the other end. The association of diarrhea with other variables--dam breed, sire, gestation group, gestation length, size of litter, number of mummies, runts or stillbirths per litter, farrowing barn of birth or day of the week farrowed--was weak or nonexistent (P greater than 0.01).     

Lameness and fertility of sows and gilts in randomly selected loose-housed herds in Finland

The prevalence of lameness among 646 sows and gilts in 21 selected herds was determined; 8.8 per cent of the animals were lame and the most common clinical diagnoses were osteochondrosis, infected skin lesions and claw lesions. The lame animals had higher serum concentrations of haptoglobin and C-reactive protein than the sound animals. Animals housed on slatted floors had twice the odds of being lame and 3.7 times the odds of being severely lame than animals housed on solid floors. Yorkshire pigs had 2.7 times the odds of being lame than Landrace or crossbred animals. Higher parity and the use of roughage decreased the odds of the sows not becoming pregnant; however, lameness was not a risk factor for non-pregnancy.     

Response of young pigs to foot-and-mouth disease oil emulsion vaccination in the presence and absence of maternally derived neutralising antibodies

Serum samples and bodyweights were taken at regular intervals for six to seven months from piglets, born to foot-and-mouth disease (FMD) vaccinated or unvaccinated sows, which had been vaccinated at one, two, four or eight weeks old. Young pigs, devoid of maternally derived antibodies (MDA), were capable of responding to FMD vaccination at one week old, with no deleterious effects on their growth rate. However, their immunity to experimental infection at six to seven months old was poor (33.3 per cent). Vaccination of four or eight-week-old piglets, born to unvaccinated sows, protected 87.5 per cent from a similar challenge. In piglets, born to FMD vaccinated sows, the MDA had a suppressive effect on the early vaccination response. This suppression, which was affected by the titre of MDA present in the piglets at the time of vaccination, was complete in one-, two- and four-week-old piglets and partial in eight-week-old piglets. Furthermore, none of these piglets were immune to experimental infection at six to seven months old.     

Evaluation of patterns of removal and associations among culling because of lameness and sow productivity traits in swine breeding herds

OBJECTIVE: To characterize patterns of removal and evaluate the associations among culling because of lameness and sow productivity traits among culled gilts and sows. DESIGN: Cross-sectional study. SAMPLE POPULATION: Data from a convenience sample of 11 farms pertaining to the removal of 51,795 gilts and sows from January 1991 to December 2002. Mean culling and mortality (death and euthanasia) rates for all inventoried gilts and sows ranged from 23% to 50% and 4.7% to 9.5%, respectively. PROCEDURE: An analysis of categories of removal (cull, death, or euthanasia) and reasons for removal of gilts and sows was performed. Multivariate logistic regression was used to determine associations among culling because of lameness and sow productivity traits among culled gilts and sows. RESULTS: Among sows that were removed, the proportion of parity > or = 1 sows that died (both death and euthanasia) was > 3 times the proportion of parity > or = 1 sows that were culled within 20 days after farrowing. Among lame sows that were removed, the proportion of parity > or = 1 sows that died (death and euthanasia) was higher than the proportion of parity > or = 1 sows that were culled within 20 days after farrowing. Among sows that were removed, the proportion of sows that died (deaths and euthanasia) was higher during lactation than nonlactation. This was also observed among lame sows that were removed. CONCLUSIONS AND CLINICAL RELEVANCE: The proportion of death among removed sows, especially lame sows, was higher during lactation than nonlactation. Results indicated that risk of death is not the same for sows throughout their lifetime.     

The Duration of Farrowing in Relation to the Reproductive Performance of Yorkshire Sows

Records for 212 attended farrowings by 38 Yorkshire sows were examined. Eighty per cent of the farrowings were less than six hours, 18 per cent between six and 12 hours and two per cent between 12 and 17 hours duration. There appeared to be no marked relationship between the duration of farrowing and the size of litter.

In spite of a higher stillbirth rate in males, there were more male (52.3 per cent) than female piglets born alive. As the time taken to farrow increased from within 1-3 hours to more than eight hours, the percentage of stillborn piglets and the percentage of litters with stillbirths increased to 10.5 from 2.4 and to 61.1 from 18.2 per cent respectively.

Twenty-nine per cent of the litters were farrowed on the 114th day of gestation. As the gestation period lengthened to 117 days or more, from 113 days or less, there were corresponding increases in the duration of farrowing and the incidence of stillbirths, and a decrease in litter size.

A need to investigate the use of hormones to control parturition in sows was suggested.

     

Protection of the nursing pig against experimentally induced enteric colibacillosis by vaccination of dam with fimbrial antigens of E coli (K88, K99 and 987P)

Pregnant gilts were vaccinated with two doses of alhydrogel adsorbed fimbrial antigens of Escherichia coli (K88ab, K88ac, K99 and 987P) supplemented with beta toxoid of Clostridium perfringens type C. Their piglets, and piglets of nonvaccinated gilts, were subsequently orogastrically challenged with one or other of the four fimbrial types of enteropathogenic E coli. Some of the vaccinated animals were reinjected with a single dose of the vaccine during second gestation and their piglets, and piglets of non-vaccinated sows, were challenged the same way as were litters of gilts. Blood serum and colostra were examined for antibodies to the four fimbrial antigens of E coli and for antitoxin to beta toxin of C perfringens type C. It was found that: (1) a highly significant reduction in mortality and morbidity was achieved in vaccinated litters against all four challenge strains of E coli; (2) excretion of K88ab and K88ac but not of K99 and 987P challenge strains was significantly reduced; (3) revaccination of sows by a single dose of the vaccine during second gestation conferred complete protection against mortality and highly significant protection against morbidity; (4) no correlation was noted between colostral or seroagglutinins to fimbrial antigens of E coli and mortality rates in litters challenged with homologous fimbrial types of E coli, but good correlation was found between colostral precipitins to K88 antigens and mortality rates in litters; (5) antitoxin value in 97 per cent of colostrum of vaccinated sows was 10 iu equivalent of C perfringens type C toxin or more per ml of colostrum.     

Effect of intramuscularly administered beta-carotene on reproductive performance in sows

The present study investigated the effects of intramuscularly administered beta-carotene on reproductive parameters in female pigs. A total of 216 multiparous sows were observed from weaning of their litters until the next farrowing. On the day of weaning, the animals were allocated to two groups. Sows of the treatment group were injected with 70 mg beta-carotene both at the day of weaning and after the last insemination, sows of the control group were left untreated. For all sows, intramuscular injection of beta-carotene resulted in a significant increase of the total number of piglets born per litter by 1.2 (p < 0.05). When sows were divided by parity, beta-carotene treatment in second parity sows increased the total number of piglets per litter (beta-carotene 13.7 +/- 1.2, control 11.2 +/- 3.7, p < 0.01) and the number of piglets born alive (beta-carotene 12.0 +/- 2.7, control 10.0 +/- 3.4, p < 0.05). No such effect was seen in sows of third or higher parity. No other reproductive parameters were affected by beta-carotene supplementation. Tolerability and safety of the administered preparation were good. No side effects related to the medication were observed. The effect of beta-carotene on reproduction is thus affected by parity of the sows. This effect seems to be exerted mainly during early pregnancy and is most likely beta-carotene-specific and independent from its role as a vitamin A precursor.     

Serological survey of encephalomyocarditis virus infection in pigs in France

Samples of serum from 76 gilts, 1440 sows, 1473 piglets and 3093 finishing pigs from 96 farrow-to-finish herds were tested for antibodies to encephalomyocarditis virus (EMCV) in microtitre serum neutralisation tests employing two strains of virus, one associated with myocarditis and the other with reproductive failure. The total seroprevalence of EMCV infection was 2.48 per cent. There was no significant difference between the seroprevalence of the reproductive failure strain (1.6 per cent) and the myocardial strain (1.85 per cent). The seroprevalence was higher in the gilts (6.57 per cent) and sows (5.13 per cent) than in the piglets (1 per cent) and finishing pigs (1.84 per cent), and the highest titres were observed in the sows (1:540) and finishing pigs (1:640). In the gilts, the difference in seroprevalence between the reproductive failure strain (3.95 per cent) and the myocardial strain (5.33 per cent) was wider than in the other groups.     

Between-breed variability of stillbirth and its relationship with sow and piglet characteristics

Litter characteristics at birth were recorded in 4 genetic types of sows with differing maternal abilities. Eighty-two litters from F(1) Duroc x Large White sows, 651 litters from Large White sows, 63 litters from Meishan sows, and 173 litters from Laconie sows were considered. Statistical models included random effects of sow, litter, or both; fixed effects of sow genetic type, parity, birth assistance, and piglet sex, as well as gestation length, farrowing duration, piglet birth weight, and litter size as linear covariates. The quadratic components of the last 2 factors were also considered. For statistical analyses, GLM were first considered, assuming a binomial distribution of stillbirth. Hierarchical models were also fitted to the data to take into account correlations among piglets from the same litter. Model selection was performed based on deviance and deviance information criterion. Finally, standard and robust generalized estimating equations (GEE) procedures were applied to quantify the importance of each effect on a piglet's probability of stillbirth. The 5 most important factors involved were, in decreasing order (contribution of each effect to variance reduction): difference between piglet birth weight and the litter mean (2.36%), individual birth weight (2.25%), piglet sex (1.01%), farrowing duration (0.99%), and sow genetic type (0.94%). Probability of stillbirth was greater for lighter piglets, for male piglets, and for piglets from small or very large litters. Probability of stillbirth increased with sow parity number and with farrowing duration. Piglets born from Meishan sows had a lower risk of stillbirth (P < 0.0001) and were little affected by the sources of variation mentioned above compared with the 3 other sow genetic types. Standard and robust GEE approaches gave similar results despite some disequilibrium in the data set structure highlighted with the robust GEE approach.     

Control of fertility outcome in artificially inseminated gilts and old sows. 1: Electric stimulation of estrous sows. Its effect on insemination results

Fifty gilts and 33 old sows which exhibited oestrous after bio-engineering treatment were electrically stimulated during insemination, using an A.C. mains-connected unit. The average voltages applied were 3.7 volt for gilts and between 2.5 and 2.8 volt for the old sows. The current was applied rectally, and the responsiveness differed individually. The treated animals then were compared to unstimulated controls, and the achievement in terms of born piglets was 1.18 more for gilts and 1.20 more for the old sows. Those better results were attributed to electric acceleration of sperm transport.     

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.     

Prevalence of congenital abnormalities in pigs

The prevalence of congenital defects in piglets in a large intensive piggery was determined by autopsy examination of piglets dying in the first week of life and from records kept by the farm staff. A total of 1908 piglets was examined at autopsy and 14,535 were born over the period of the survey. The prevalence of defects on this farm was estimated to be 2.9% of all piglets born, and at least one piglet with a congenital defect was found in 17.4% of litters. Of the piglets dying in the first week 9.5% had a defect and of these 8% had multiple anomalies. The mean litter size at birth for litters with a malformed piglet was 10.9 compared with 9.9 for litters without a malformed piglet. The total preweaning loss in litters containing a malformed pig was higher (29.8%) than that in litters without malformations (17.4%). The antepartum and parturient deaths in litters with a malformed piglet were 35% higher than normal litters. Parturient and anteparturient deaths amounted to 7.5% of piglets born and the total preweaning mortality was 19.9%. Sixty-six per cent of these mortalities occurred within the first week of life. The litter size at birth increased with parity as did the prevalence of litters containing malformed piglets. Neonatal loss was about 2 pigs per litter for all parities. Litter size at birth in litters containing a malformed pig was consistently higher by one pig per litter from all parities, but parturient (7.1%) and anteparturient (1.4%) deaths were also higher in these litters than in litters without malformations (5.1% and 1.2% respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

非洲猪瘟背景下企业留种三元与二元母猪产仔数的比较研究

主要通过比较丹系和加系纯种、二元和三元母猪的窝产健仔数,分析不同遗传背景及胎次的母猪产仔性能差异,为评估三元母猪产仔性能及其替代更新提供参考依据.研究整理了国内某规模化企业2019年5月至2020年8月间猪场的209963条产仔记录,其中丹系56016窝,加系153947窝,通过单因素方差分析及邓肯检验对2个品系的母猪...     

Enteric colonisation following natural exposure to Campylobacter in pigs

A survey was conducted to establish the prevalence of Campylobacter in pigs from an integrated commercial hog farm. This study was carried out in four different groups of pigs: 1) adult gilts (50); 2) pregnant sows (9); 3) piglets at day-of-birth (73); 4) weaned piglets (20). Rectal and/or caecal samples were collected from each pig. Campylobacter was cultured and enumerated from such samples using Bolton enrichment broth and Campy-Cephex agar plates. Both biochemical and serological tests were used to determine Campylobacter species. Gilts had a 76 per cent incidence of Campylobacter with a mean of 76.3 per cent for C. jejuni, 21 per cent for C. coli and 2.6 per cent for C. lari. Pregnant sows had a 100 per cent incidence of Campylobacter with a mean of 87 per cent for C. jejuni and 13 per cent for C. coli. Newborn piglets had a 57. 8 per cent incidence of Campylobacter, rising to 100 per cent by the time of weaning. Thus it appears that pigs, from the day of birth, are highly susceptible to colonisation by Campylobacter.