Vaccine efficacy for reducing turbinate atrophy and improving growth rate in piggeries with endemic atrophic rhinitis

Two vaccines, based on formalin-killed whole cells of toxigenic Pasteurella multocida type D and Bordetella bronchiseptica combined with a partially toxoided cell extract of P multocida, were prepared with Freund's incomplete adjuvant (vaccine 1) or by alum precipitation (vaccine 2). Each was tested for safety and efficacy in reducing the severity of nasal turbinate atrophy and improving the growth rate of pigs in three Western Australian commercial piggeries with endemic atrophic rhinitis. In safety experiments with vaccine 1, no adverse clinical effects were observed in vaccinated sows or their progeny. Piglets receiving vaccine 2 showed no injection site abnormalities, pyrexia or turbinate atrophy. In field trials, vaccine 1 significantly reduced the prevalence of moderate to severe nasal turbinate atrophy (Done score 3 to 5) when used in two piggeries (A and B). Progeny from vaccinated sows in piggery B also grew significantly faster than controls. When vaccine 2 was used in piggery A at a later date and in another piggery (C), growth rate was not improved in either piggery and the prevalence of moderate to severe turbinate atrophy was reduced only in piggery C.     

Epidemiological studies of Brachyspira pilosicoli in two Australian piggeries

The epidemiology of infection with the intestinal spirochaete Brachyspira pilosicoli within pig herds is incompletely understood. To investigate this further, cross-sectional and cohort studies were undertaken on two piggeries. Faeces were subjected to selective culture, and DNA was extracted from growth on the primary media and amplified by polymerase chain reaction (PCR). On one farm, samples from other animal species and the environment were also examined. Isolates were subjected to multilocus enzyme electrophoresis (MLEE) and pulsed field gel electrophoresis (PFGE). The prevalence on farm A (>2000 sows) was 2.4% (95% confidence interval (CI): 0.3, 4.4%). Infection was largely confined to grower/finisher pigs. The six isolates of B. pilosicoli recovered belonged to a single MLEE electrophoretic type (ET) and a single PFGE type. On piggery B, an 80-sow unit located on a research farm, the prevalence amongst growers and finishers was 12.2% (95% CI: 4.7, 19.6%). There was also evidence that weaners were being infected. Ten isolates obtained were genetically heterogeneous, being divided into six ETs and seven PFGE types. One of four isolates in one ET had an identical PFGE type to those on piggery A, and may have been introduced to piggery B in stock from piggery A. On farm B, B. pilosicoli was also detected by PCR in chickens, effluent pond water and wild ducks on the pond. An isolate from the pond belonged to the same ET as one from a pig, whereas the duck isolates were distinct. This study demonstrates the complex epidemiology of B. pilosicoli infections in piggeries.     

Leptospirosis outbreak in a piggery in southern alberta

Fourteen abortions, stillbirths and neonatal deaths occurred over an interval of one month in crated sows in a farrow-to-finish swine operation. Leptospira interrogans serovar pomona (kennewicki by DNA analysis) was demonstrated by culture and fluorescent antibody test to be present in sows, piglets, boars, feeders, drinking water and skunks on the premises.

Antibody was found in all clinically affected sows, at serum dilutions ranging from 1/800 to 1/25,600, and in all breeding boars at titers from 1/50 to 1/1600. Pomona antibody was present in 118 sow sera collected nine months before the outbreak, at a prevalence of 21.3%. Parvovirus infection in fetuses was intercurrent with the leptospirosis epizootic, despite vaccination for the former. Environmental contamination, feedback through skunks via drinking water, and dissemination through the piggery are discussed.

     

Leptospirosis in pigs: Vaccination to control perinatal deaths in piglets

Extract

Perinatal deaths are common among piglets in New Zealand. They tend to occur in epidemics, they are independent of the type of soil or of feeding practices, and are most common in the litters of young sows and of those recently introduced into the piggery. Affected sows may show signs of sickness and inappetence before farrowing, and the piglets are usually born dead (delivered in intact foctal membranes) or they may be weak and die within 24 hours of birth. A sow that has once delivered dead piglets rarely, if ever, does so at later farrows.     

The rapid appearance of anthelmintic resistance on a sheep farm

A sudden outbreak of perinatal mortality in piglets occurred between May and August 1991 in a 60-sow piggery near Palmerston North. None of the piglets born to the 30 sows which farrowed during this period of time survived more than a few days and all live-born piglets appeared weak. Three newborn live piglets were humanely killed and at necropsy had marked diffuse subcutaneous oedema, the only gross and histological anomalies detected in the extensive range of tissues examined. Serological tests of sows were negative for leptospiral, porcine herpes viral (Aujeszky's), porcine parvoviral, encephalomyocarditis viral and Brucelh suis infections. No viral agents were recovered on cell culture from pooled piglet tissues. Liver selenium levels were normal, but Vitamin E values (0.8, 0.8 and 0.6 μmol/kg respectively) seemed low according to the recently established range of 0.9-1.4 μmol/kg for normal unsuckled piglets in New Zealand⁽¹⁾. No Vitamin E/selenium deficiency syndromes had been recognised previously in this herd.     

Epidemiology and control of Menangle virus in pigs

OBJECTIVE: To describe the epidemiology and eradication of Menangle virus infection in pigs. DESIGN: Field observations and interventions, structured and unstructured serological surveys, prospective and cross-sectional serological studies and laboratory investigations. PROCEDURE: Serum samples were collected from pigs at a 2600-sow intensive piggery in New South Wales that experienced an outbreak of reproductive disease in 1997. Serum samples were also collected from piggeries that received pigs from or supplied pigs to the affected piggery and from other piggeries in Australia. Serum and tissue samples were collected from pigs at piggeries experiencing reproductive disease in New South Wales. Sera and faeces were collected from grey-headed flying foxes (Pteropus poliocephalus) in the region of the affected piggery. Serum samples were tested for neutralising antibodies against Menangle virus. Virus isolation was attempted from faeces. RESULTS: Following the outbreak of reproductive disease, sera from 96% of adult pigs at the affected piggery, including sows that produced affected litters, contained neutralising antibodies against Menangle virus. Neutralising antibodies were also detected in sera from 88% of finisher pigs at two piggeries receiving weaned pigs from the affected piggery. No evidence of Menangle virus infection was found in other piggeries in Australia. In cross-sectional studies at the affected piggery, colostral antibodies were undetectable in most pigs by 14 to 15 weeks of age. By slaughter age or entry to the breeding herd, 95% of pigs developed high antibody titres (> or = 128) against Menangle virus in the virus neutralisation test. Menangle virus was eradicated from the affected piggery following a program of serological testing and segregation. Neutralising antibodies against Menangle virus were also detected in P poliocephalus from two colonies in the vicinity of the affected piggery. Two piggery workers were infected with Menangle virus. There was no evidence of infection in cattle, sheep, birds, rodents, feral cats and a dog at the affected piggery. CONCLUSIONS: Serological evidence of infection with Menangle virus was detected in pigs at a piggery that had experienced reproductive disease, in pigs at two associated piggeries and in fruit bats in the region of the piggery. Two humans were infected. The mode of transmission between pigs is unknown, but spread by faecal or urinary excretion is postulated. This virus can be eradicated by the segregation of pigs into discrete age groups.     

An association between encephalomyocarditis virus infection and reproductive failure in pigs

An outbreak of reproductive failure, characterised by mummified foetuses and stillbirths, was investigated in an intensive piggery. Six foetuses that died towards the end of gestation had multifocal myocardial necrosis and encephalomyocarditis virus was recovered from 4 of these foetuses but not from 6 mummified foetuses. There was also a significant increase in failure of conception or early embryonic deaths in sows mated at the same time as sows which produced affected litters.     

INTESTINAL RUPTURE IN SOWS FED WHEY

A problem of sudden deaths was investigated on a 600 sow piggery after 35 (8%) mature sows died during 10 months. Thirty four (90%) of the sows which died in the following 20 months were all fed whey and had acute severe peritonitis associated with rupture of the large or lower small intestine. No similar deaths occurred in sows, gilts or boars receiving only formulated feed pellets. It is suggested that ruptures resulted from overdistention with gas produced from whey and that the likelihood of their occurrence was directly related to the volume of whey ingested.     

Reproductive disease and congenital malformations caused by Menangle virus in pigs

OBJECTIVE: To describe a new syndrome characterised by embryonic mortalities, stillbirths, mummified foetuses and congenital malformations in a herd of intensively farmed pigs. DESIGN: Field observations, laboratory investigations and examination of breeding records. PROCEDURE: Pathology examinations were performed on mummified and congenitally deformed piglets during an outbreak of reproductive disease at a 2600 sow intensive piggery in New South Wales from April to October 1997. Reproductive performance was monitored during the outbreak and breeding records were examined retrospectively. Serum and tissue samples from pigs were tested for evidence of infection with known porcine pathogens and for a new virus, Menangle virus, isolated from stillborn piglets with deformities from the affected piggery in August 1997. RESULTS: Reproductive disease occurred sequentially in all four breeding units at the affected piggery over a period of 21 weeks. The farrowing percentages in each unit decreased from 80 to 82% before the outbreak to 63 to 78% during the outbreak and the number of live piglets per litter declined from a mean of 9.6 to 9.8 before the outbreak to 7.2 to 8.9 during the outbreak. The proportion of affected litters (litters with less than six liveborn piglets) was highest (64%) in the sixth week of the outbreak. Mummified foetuses, stillborn piglets with arthrogryposis, craniofacial deformities and degeneration of the brain and spinal cord, were observed along with occasional abortions. Sera from sows that produced affected litters contained neutralising antibodies against Menangle virus and there was evidence that this virus had been introduced to the piggery in February 1997. CONCLUSIONS: Reproductive disease in pigs due to Menangle virus was characterised by stillbirths, mummification, embryonic death and infertility, along with abortions, skeletal deformities and degeneration of the brain and spinal cord in affected foetuses and stillborn piglets.     

Fertility of sows mated on different days of the week

The farrowing rates resulting from matings on different days of the week were determined for a 2800-sow intensive piggery in both 1983 and 1984. The results showed that sows mated early in the week achieved a significantly higher farrowing rate than sows mated late in the week (P less than 0.0001). During the seasonal (summer to autumn) infertility period, Wednesday matings resulted in a poor farrowing rate whereas for the rest of the year farrowing rates following Wednesday matings were similar to those for Sunday Monday and Tuesday matings. Consistent results were obtained for data from both years. It is proposed that the stress of regrouping unmated sows on Wednesday to accommodate newly weaned sows is responsible for this decrease in fertility. This study illustrates how detailed analysis of farrowing rates on a day of mating basis can identify a problem which is otherwise masked by weekly data.     

Feeding sorghum ergot (Claviceps africana) to sows before farrowing inhibits milk production

Objective To assess the impact of feeding different amounts of sorghum ergot to sows before farrowing. Design Fifty‐one pregnant sows from a continually farrowing piggery were sequentially inducted into the experiment each week in groups of four to seven, as they approached within 14 days of farrowing. Diets containing sorghum ergot sclerotia within the range of 0 (control) up to 1.5% w/w (1.5% ergot provided 7 mg alkaloids/kg, including 6 mg dihydroergosine/kg) were randomly allocated and individually fed to sows. Ergot concentrations were varied with each subsequent group until an acceptable level of tolerance was achieved. Diets with ergot were replaced with control diets after farrowing. Post‐farrowing milk production was assessed by direct palpation and observation of udders, and by piglet responses and growth. Blood samples were taken from sows on three days each week, for prolactin estimation. Results Three sows fed 1.5% ergot for 6 to 10 days preceding farrowing produced no milk, and 87% of their piglets died despite supplementary feeding of natural and artificial colostrums, milk replacer, and attempts to foster them onto normally lactating sows. Ergot inclusions of 0.6% to 1.2% caused lesser problems in milk release and neo‐natal piglet mortality. Of 23 sows fed either 0.3% or 0.6% ergot, lactation of only two first‐litter sows were affected. Ergot caused pronounced reductions in blood prolactin, and first‐litter sows had lower plasma prolactin than multiparous sows, increasing their susceptibility to ergot. Conclusion Sorghum ergot should not exceed 0.3% (1 mg alkaloid/kg) in diets of multiparous sows fed before farrowing, and should be limited to 0.1% for primiparous sows, or avoided completely.     

Prevalence of Eimeria spp. in Sows at Piglet‐producing Farms in Germany

The prevalence of Eimeria infections was investigated in an initial survey in 54 sow herds of small (five sows) to large (1600 sows) size by random sampling (n = 1204). All sows of four Eimeria‐positive medium‐sized farms (63 or 130 sows) were re‐examined 40–99 days after the first visit. A follow‐up survey over the whole reproductive cycle was subsequently performed in a positive herd of 130 animals where faecal samples of 43 sows were repeatedly collected on seven successive farm visits. In 44 farms (81.5%) parasite stages (eggs of strongylids, Trichuris, Ascaris, Strongyloides, oocysts of Eimeria and Isospora) were identified in sow faeces, strongylids being the most prevalent intestinal parasites (34 farms resembling 63%) followed by Eimeria spp. (28 farms resembling 52%). Of the 1204 random samples collected during the initial survey 8.6% contained Eimeria oocysts. Oocysts of E. polita and E. debliecki were present in each of 25 Eimeria‐positive samples selected for species differentiation. Eimeria suis was diagnosed in 84%, E. scabra in 60%, E. porci in 52%, E. perminuta in 49% and E. spinosa in 20% of these specimens. At the second visit the prevalence rates of Eimeria infections had either increased or decreased. In the follow‐up study Eimeria infections were found to be most frequent (82%) at the service station. At the quarantine unit and the gestation stable 50 and 48% of the 43 sows were Eimeria positive. The lowest prevalence of Eimeria infection was observed in the farrowing unit (14%). With respect to the reproductive state of the sows highest infection rates were seen 2 weeks after weaning (72%) continuously decreasing until 2 weeks after farrowing (14%). A periparturient rise of oocyst excretion was not observed. The infestation rate remained low until 1 week before weaning (16%). Low infection intensities clearly dominated. Clinical disease was not associated with Eimeria infection.     

A leptospirosis outbreak in a piggery

A newly established piggery experienced an abortion storm that was diagnosed as being caused by Leptospira pomona. Serumantibody titres and urine culture indicated the rapid spread of infection within the piggery, and established the period since infection began. This showed the origin of infection to beone of the piggeries from which stock were purchased.

Histological and microbiological studies indicated the continuing presence of L. pomona as the cause of abortion. Initial treatment with dihydrostreptomycin and “Leptovax” had no effect on preventing infection, and the subsequent use of “Terramycin” caused little modification to the spread of infection or prevention of abortions. The spread of leptospirosis through the herd resulted in a marked increase in the number of piglets aborted or born dead and, subsequently, a poor survival rate of piglets reared through to slaughter. Efforts are being made to control leptospirosis within the piggery, but eradication is currently considered to be almost impossible.     

Milk Production in Sows after Spontaneous Delivery and after Delivery Induced by PGF2α Analogs

In this study the amount of milk produced during the first week of lactation was compared in sows with induced parturition and sows which delivered spontaneously (with special attention to sows showing MMA symptoms). Fifteen sows (L X LW) were used from a pig farm in which MMA was seen in 20 to 25% of all farrowings. The animals were divided into three groups of 5 each. Group A and B were treated with two different PGF ₂ α analogs (2 mg of alfaprostol or 0.45 mg of tiaprost) on 111 day of pregnancy, and group C (control) with 2 ml of saline solution. Treatment with PGF analogs induced parturitions 24 to 30 h later, controls delivered spontaneously on day 114. Litters were equalized to nine piglets per sow. The milk yield of each sow was calculate using the method of weighing piglets before and after each suckling. Piglets were allowed to suckle 12 times in the first 24 h after parturition, then 8 or 9 times in the next 24 h and from 48 h onwards 8 times during 24 h, until the end of the 7 day observation period. During the first day after parturition the control group appeared to produce slightly more milk than groups A and B whereas from 24 to 48 h, milk yields decreased in all animals. From 48 onwards milk production increased in all groups. Between 72–96 h, two sows of the control group showed symptoms of MMA and their piglets developed diarrhea. Microbiological analysis confirmed the presence of haemolytic Streptococci. The lactation curves of treated and untreated sows with no signs of MMA were very similar; the pattern was more erratic in sows with MMA. The total milk yields during the first week of lactation did not differ between groups; there were no significative difference in the weight gain of the piglets in groups A, B and C. The difference recorded in milk yield and release patterns between sows with or without MMA opens new aspects with regard to the aetiology of a syndrome that not only involves the sows health, but produces intestinals disease in their piglets.     

Seroprevalence and risk factors associated with seropositivity in sows from 67 herds in north-west Germany infected with Mycoplasma hyopneumoniae

Risk factors for the spread of Mycoplasma hyopneumoniae in sows have not been studied although vertical transmission from sows to their offspring is considered a significant risk factor in the development of enzootic pneumonia in growers and finishers. Seropositivity for M. hyopneumoniae in sows, as assessed by commercial ELISA, is a possible indicator of infection pressure among sows. The objective of this study was to estimate seroprevalence and associated risk factors of a sow being seropositive for M. hyopneumoniae. A cross-sectional study was carried out in 2578 sows from 67 herds in north-west Germany. Data concerning general herd characteristics, acclimatisation practices, indoor and outside contacts, as well as data describing the immediate local environment were collected during a herd visit via questionnaire. Blood samples were seropositive in 65% of the 2578 sows, and all herds had ≥14% seropositive sows. Data analysis was performed in two steps. First, univariate analysis of predictor variables for the risk of a sow being seropositive for M. hyopneumoniae was performed using chi-square test. Secondly, all variables associated with the risk of a sow being seropositive (P ≤ 0.25) were included in a multivariate model using a generalised linear model. The risk of a sow being seropositive for M. hyopneumoniae was increased in herds with two- or three-site production (OR 1.50), when piglets were not vaccinated against M. hyopneumoniae (OR 1.81), in herds with a 2-week farrowing intervals (OR 1.84) and in herds without all-in/all-out management of the farrowing units (OR 1.37). The lack of an acclimatisation period for replacement boars was also associated with the risk of a sow being seropositive (OR 2.10). The results indicate that M. hyopneumoniae seropositivity is common in sows in north-west Germany and is influenced by various management factors. It is recommended that evaluation of sow herd management should be included in any strategic health plan to control M. hyopneumoniae infection.     

Reproductive Performance of Purebred Swedish Landrace and Swedish Yorkshire Sows: I. Seasonal Variation and Parity Influence

The objective of this retrospective study was to investigate the causes of variation in the reproductive performance of purebred Swedish Landrace (L) and Swedish Yorkshire (Y) sows. Data analysed comprised farrowings from 1994 through 1997 from 19 Swedish nucleus herds and included 20 275 litters from 6989 purebred sows (3598 L and 3491 Y). The main traits analysed were litter size, weaning-to-first-service interval (WSI), farrowing rate, remating rate and age at first farrowing. Analysis of variance was used for the statistical analysis of quantitative data. Logistic regression analysis was applied for binary data using the GLIMMIX macro in the SAS program. Factors included in the analyses were breed of sow, breed of boar, parity number, herd-year combination within breed, mating type (natural mating or artificial insemination), lactation length and month of the year. L sows, compared with Y sows, produced larger litters [11.61 vs 11.54 total born/litter (ns) and 10.94 vs 10.58 born alive/litter (P<0.001)] and had a longer WSI (5.5 vs 5.4 days, P<0.001), a higher farrowing rate (82.8 vs 80.9% units, P<0.05) and a lower remating rate (6.2 vs 8.8% units, P<0.001). On average, L sows were younger at first farrowing than Y sows (355.6 vs 368.6 days, P<0.001). The seasonal influence on WSI was greater for primiparous sows than for multiparous sows. Primiparous sows weaned from June to October had a longer WSI than those weaned from January to May or in November (P<0.05). Mating in August resulted in the lowest farrowing rate and the highest remating rate. The seasonal influence on farrowing rate and WSI was more pronounced in Y sows than in L sows. However, season had no significant influence on litter size in either L or Y sows.     

Sows Intramammarily Inoculated with Escherichia coli: Influence of Time of Infection,Hormone Concentrations and Leucocyte Numbers on Development of Disease

The aim of this study was to identify factors that influence the development of disease in sows inoculated with Escherichia coli in the mammary gland. Ten cross‐bred primiparous sows were intramammarily inoculated with living E. coli bacteria at different time points before parturition: seven sows within 48 h before parturition and three sows approximately 96 h before parturition. Before and after inoculation, blood samples and mammary gland biopsy specimens were collected and clinical observations were made. All seven sows inoculated close to parturition developed a rectal temperature of >39.5°C during the first 48 h post‐partum and two of them also showed other signs of clinical disease. In the sows inoculated 4 days before parturition, the rectal temperature never exceeded 39.5°C during the first 48 h post‐partum and none of them showed any other sign of clinical disease. There was a tendency (P < 0.1) that histological signs of mastitis were more frequent in the sows inoculated close to parturition. There were no overall differences between the two groups of sows in plasma concentrations of cortisol, oestradiol‐17β and 15‐ketodihydro‐PGF_2α before inoculation. Before inoculation, the number of neutrophils in the blood was overall higher (P < 0.05) in the group of sows that were inoculated close to parturition. In comparison, the number of lymphocytes before inoculation had a tendency (P < 0.1) to be lower in that group. The data suggest that the time of infection of the mammary gland relative to parturition and the number of circulating neutrophils at the time of infection influence the development of clinical coliform mastitis in the sow.     

Influence of mastitis metritis agalactia (MMA) on bone and fat metabolism

Mastitis metritis agalactia (MMA) is a common disease in post-partum sows and has a negative effect on sows’ longevity as well as on sows’ and piglets’ health. MMA leads to an inflammatory state. The aim was to investigate the impact of MMA on bone and fat metabolism. The hypothesis was that it is possible to predict MMA by measuring ketone bodies and bone markers. Blood samples from 175 sows were taken within 72 hr after farrowing. Serum was analysed for 25-hydroxyvitamin D (25-(OH)-D), serum crosslaps (CTX-I), osteocalcin (OC), alkaline phosphatase (ALP), calcium (Ca), magnesium (Mg), phosphorus (P), parathyroid hormone (PTH), triglycerides (TG), beta-hydroxybutyric acid (BHB), tumour necrosis factor-alpha (TNF-α) and haptoglobin. Spontaneous urine was collected, and pH value was measured in addition to Ca and P. A proximate analysis of the sows’ diets was performed. Age, litter size, body condition score (BCS) and clinical signs of MMA were recorded for each sow. A multivariable logistic regression was undertaken with disease status (MMA or healthy) as the dependent variable. Significance was accepted at p < .05. MMA sows had a poorer BCS (p < .001) in relation to healthy sows. Age and number of piglets did not differ. MMA sows showed increased serum CTX-I (p = .004) and decreased serum OC (p < .001). Concentrations of P (p = .007), activity of ALP (p = .002) and BHB (p = .019) as well as TNF-α (p < .001) and haptoglobin (p = .048) concentrations were increased in MMA sows. No difference in urinary pH value between MMA and healthy sows was found. Our results are in accordance with the known fact that sows are in an extreme catabolic state peripartum. Bone metabolism in MMA sows is much more negatively affected than in healthy sows post-partum, due to inflammatory processes shown by higher concentrations of pro-inflammatory cytokines.     

Lactation efficiency as a result of body composition dynamics and feed intake in sows

Through genetic selection and improvement of environment, litter size of sows increases. Increased energy requirement during lactation, increases the risk of excessive mobilization from body stores, with detrimental effects on reproductive performance. Feed intake capacity tends to decrease due to selection towards leaner pigs with a lower feed conversion ratio. However, to facilitate sows to wean large litters extra feed intake, or even better, a higher feed efficiency during lactation would be favourable. The objective of the present study was to describe the dynamics of body composition of sows and piglets during lactation, and to relate these traits to a newly introduced trait called “lactation efficiency”. Energy metabolism of lactating sows was described, based on on-farm observations of weight and backfat of sows before parturition and at weaning, weight of piglets at birth and at weaning and feed intake of sows during lactation. “Lactation efficiency” was defined as energy efficiency of sows, and calculated for individual sows at two different farms. The average lactation efficiency was 68% and 65% for both farms; meaning that 68 and 65% of the metabolisable energy through feed intake or mobilization from body stores, above maintenance of the sow (input), was used for piglet growth and piglet maintenance (output). The association between lactation efficiency and other reproductive traits was studied by estimating the correlations within farms. Sows with a higher lactation efficiency showed lower feed intake (r = − 0.27 and r = − 0.35 for both farms respectively) and smaller fat losses (r = − 0.34 and r = − 0.29, respectively). The energy output of efficient sows was slightly higher (r = 0.23 and r = 0.30). The more efficient sows were the better mothers, as mortality of their piglets was lower (r = − 0.12 and r = − 0.16), piglet growth rate was higher (r = 0.16 and r = 0.23), and at weaning their litters were less variable (r = − 0.08; only available at one farm). Results were remarkably similar for the two farms, despite different feeding strategies. Extra input, by means of feed intake or mobilization from body stores generated extra output by means of litter weight at weaning. This experiment demonstrated that an accurate recording of energy metabolism and relevant reproduction traits with little intervention is possible on commercial farms.     

Proliferative haemorrhagic enteropathy in pigs.

An outbreak of proliferative haemorrhagic enteropathy (PHE) occurred in two epidodes and affected 372 adult pigs in the breeding units of a minimal disease piggery; 186 pigs died. In the initial episode breeding sows and boars of all ages were affected, suggesting infection of a fully susceptible population. Animals involved in the first episode of the disease did not show clinical symptoms at a later date and further clinical cases occurred only in animals introduced into the breeding population. Antibiotic feed medication was an effective method of prophylaxis. Bacteria resembling Campylobacter sputorum subspecies mucosalis were isolated from the intestinal mucosa of affected animals.