Mari Heinonen

Seasonal and management effects on fertility of the sow: a descriptive study

This study was undertaken to determine management and seasonal effects on fertility in 1298 Finnish sow units over a 4-year period in 1992-1996. A multivariate analysis of the herd record data was undertaken to study the effect of various management factors on rebreeding rate. Factors found to have an effect were further subjected to time series plotting for seasonal effects. In addition, seasonal effects on the farrowing rate, age of gilts at first mating and littersize as well as the 3-week litterweight were studied. Year and month caused the most significant variation in the rebreeding rate. Moreover, geographical area, herd and way of breeding (mating vs. artificial insemination) were found to be significant determinants of rebreeding rate. Dry sows loosely housed were more likely to be rebred than sows housed in individual stalls. Sows receiving roughage feed (hay, straw) or bedding (straw) were less likely to require rebreeding. A significant seasonal fluctuation in farrowing rate was found with a nadir of 72.6% in August and a high of 80.9% in January. The average farrowing rate for the 4-year period was 77.7%. The age of gilts at first mating showed seasonal variation of 11 days (229.9 +/- 0.5 days in March and 241.4 +/- 0.5 days in November). In conclusion, this study indicates that group housing of dry sows increases the risk of rebreeding. In group housed sows, rebreeding more often occurs after an irregular oestrus-to-oestrus interval in summer-autumn whereas a not-in-pig seems to be a more common finding at late gestation in individually housed sows.

Evaluation of reproductive failure of female pigs based on slaughterhouse material and herd record survey

Reproductive organs were collected from one slaughterhouse and culling data were obtained from Finnish swine herd records to determine the types and frequencies of various fertility disturbances in Finnish female pigs. Detailed information about the type and occurrence of fertility disturbances was obtained through a close examination of the slaughterhouse material. A total of 1708 reproductive organs of female pigs were examined. The following findings were recorded: no macroscopical abnormalities 52.3%, inactive ovaries 25.1%, parovarian cysts 22.9%, single ovarian cysts 3.1%, multiple ovarian cysts 3.1%, uterine disorders 1.4%, ovarian adhesions 1.1%, congenital anomalies 0.8%, tumour-like lesions in ovaries 0.8%, obstruction of oviduct 0.2%, and suppurative ovarian infection 0.1%. A large proportion, 42% of the culled gilts and 39% of the culled sows, were slaughtered because of impaired fertility based on no pregnancy, no heat or poor piglet production. The sows were removed from the herds 33 days on average after weaning.

Environmental and sow-related factors affecting the duration of farrowing

A short duration of farrowing is important for piglet survival as a delay can increase the number of stillborn. Many factors may affect the duration of farrowing, including breed, age of the sow, length of gestation, number of piglets born, housing (CRATE vs. PEN), body condition of the sow and state of constipation. The aim of the present study was to investigate these factors and how they interact with each other and thus increasing the risk of prolonged farrowing. The total duration of farrowing and average piglet birth interval were recorded in 172 sows from two herds (HERD-1, n = 76; HERD-2, n = 96). Back-fat measurements and intestinal activity (based on the mean of a constipation index) were measured in all 172 sows. The total duration of farrowing was 272 +/- 152 min (mean +/- SD, n = 172): 301 +/- 165 min (n = 115) in the CRATE group and 212 +/- 95 min (n = 57; P < 0.05) in the PEN group. The average piglet birth interval was 26 +/- 25 min (mean +/- SD, n = 172): 29 +/- 29 min (n = 115) in the CRATE group and 19 +/- 10 min (n = 57; P < 0.05) in the PEN group. Housing (P < 0.05), stillborn (P < 0.001), back-fat average (P < 0.001) and constipation index (P < 0.05) significantly correlated with the duration of farrowing. In conclusion, allowing the sow to move freely before farrowing, reducing the constipation state and avoid excessive fattening during late pregnancy all appear to be key factors in shortening farrowing time and reducing perinatal mortality.

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.

High physiological demands in intensively raised pigs: impact on health and welfare.

Genetic selection and better control of the environment of the pigs have resulted in increased production levels concerning both reproduction and growth. Such high performances imply high physiological demands that may deteriorate health and welfare. The aims of this paper are to review the physiological challenges that pigs are facing, to identify possible consequences on health and welfare, to propose ways of detecting and correcting problems whenever possible. At weaning, piglets are submitted to abrupt changes in food supply, housing and social environment. Behavioural changes and efficient adaptations of the digestive tract are critical for their health and welfare. Physiological demands to support these adaptations and risks of failure are inversely related to the age of the pigs. During fattening, modern pigs have high daily weight gain especially of lean tissue as well as elevated feed conversion rate. These high growth performances are suspected to favour stress and disease susceptibility, undesirable behaviours as well as leg weakness, but further experimental data are necessary to validate these effects and find their origin. In reproductive females, high prolificacy generates elevated foetal demands for nutrients and space that are not fully met as shown by an increased number of light piglets having difficulties to adapt successfully to the neonatal life. During lactation, sows with high milk production have high nutrient requirements leading to intense catabolism that may affect their health, welfare and future reproductive abilities.

Feeding sows with high fibre diet around farrowing and early lactation: Impact on intestinal activity, energy balance related parameters and litter performance

The effects of fibre in diets for periparturient sows are poorly documented. Three weeks before farrowing, 41 sows (LACT) were fed a diet containing 3.8% crude fibre. Other 40 sows (FIBRE) received a diet containing 7% crude fibre. We estimated the intestinal activity of the sows with a daily qualitative evaluation of their faeces. The FIBRE group had a qualitative faeces score value of 2.1+/-1.3 and the LACT group had a value of 1.2+/-1.1 (P<0.001). Individual daily water consumption was higher in the FIBRE group than in the LACT group (P<0.001). Piglet weight gain at day 5 was higher in the FIBRE group (P<0.05). The energy balance related parameters did not differ between the treatments. Concluding, diets containing more fibre can be successfully used around farrowing reducing prolonged constipation of sows with no negative effect on their energy balance related parameters.

Tail biting induces a strong acute phase response and tail-end inflammation in finishing pigs.

The extent of inflammation associated with tail biting in finishing pigs was evaluated. Tail histopathology, carcass condemnation and the concentration of three acute phase proteins (APPs), C-reactive protein (CRP), serum amyloid-A (SAA) and haptoglobin (Hp), were examined in 12 tail-bitten and 13 control pigs. The median concentrations of APPs were higher (P<0.01) in bitten (CRP 617.5mg/L, range 80.5-969.9; SAA 128.0mg/L, 6.2-774.4; Hp 2.8g/L, 1.6-3.5) than in control pigs (CRP 65.7mg/L, 28.4-180.4; SAA 6.2mg/L, 6.2-21.4; Hp 1.2g/L, 0.9-1.5). There was a tendency for APP concentrations to rise with the histopathological score but the differences were only statistically significant between some of the scores. Five (42%) bitten cases and one (8%) control pig had partial carcass condemnations owing to abscesses (P=0.07). The results show that tail biting induces an inflammatory response in the tail end leading to an acute phase response and formation of carcass abscesses.

Oral ketoprofen is effective in the treatment of non-infectious lameness in sows.

The efficacy of ketoprofen in the treatment of non-infectious lameness in sows was examined in a double-blinded study. Two dose rates of oral ketoprofen were compared to placebo treatment over five consecutive days. Lameness was assessed with a five-grade scoring system prior to and on the last day of the treatment. The rate of treatment success was 54.3% for the ketoprofen 4mg/kg group (n=46), 53.2% for the ketoprofen 2mg/kg group (n=47) and 20.8% for the pigs in the placebo group (n=48). The difference between both ketoprofen groups and the placebo group was significant (P=0.001), but there was no difference between the two ketoprofen groups (P=0.78). Oral ketoprofen was well tolerated and no adverse events were observed. As lameness is a very common problem in sows, oral ketoprofen appeared to be a practical way to alleviate pain and improve the welfare of sows.

Prevalence of and risk factors associated with viral and bacterial pathogens in farmed European wild boar

Abstract The aim of this study was to estimate in farmed European wild boars the prevalence of and risk factors associated with a range of common porcine viral and bacterial infections, namely, porcine parvovirus (PPV), porcine circovirus type 2 (PCV2), swine influenza virus (SIV), Aujeszky’s disease virus (ADV), classical swine fever virus (CSFV), swine vesicular disease virus (SVDV), coronavirus causing transmissible gastroenteritis (TGEV), porcine reproductive and respiratory syndrome virus (PRRSV), Mycoplasma hyopneumoniae, Lawsonia intracellularis, Brucella spp., and Leptospira spp. A sampling frame was compiled based on a national record of wild boar farmers, and 32 farms were surveyed. Serological screening was carried out on 303 samples from animals slaughtered between 2005 and 2008, and random-effect logistic regression models were developed for pathogens with a ‘non-zero’ prevalence. The apparent animal prevalence for PPV, PCV2, and L. intracellularis was 46.5% (95% confidence interval [CI] 41–52%), 51.1% (95% CI 45–57%) and 59.2% (95% CI 54–65%), respectively. Apparent farm seroprevalence rates for PPV, PCV2 and Lawsonia intracellularis were 56.3% (95% CI, 39–73%), 21.9% (95% CI, 8–36%) and 78.1% (95% CI, 64–92%), respectively. No antibodies were detected against SIV, ADV, CSFV, SVDV, TGEV, PRSSV, Leptospira spp., Brucella spp., or M. hyopneumoniae. Increasing herd size, proximity to dense populations of domestic swine and later sampling times within the survey period were found to be risk factors. Overall, the seroprevalence of these pathogens in farmed wild boar was similar to that in the farmed domestic pig population in Finland. However, it is possible that the rearing of wild boars in fenced estates may predispose them to particular infections, as reflected in higher antibody titres.

Farmed wild boars exposed to Toxoplasma gondii and Trichinella spp.

The meat of wild boar (Sus scrofa L.) can be a source of human infections with zoonotic parasites Toxoplasma gondii and Trichinella spp. We screened 197 wild boar sera collected at slaughter from 25 Finnish farms in 2007-2008 for serological evidence of infections with these parasites. Using a commercial direct agglutination test at a serum dilution of 1:40, T. gondii-specific IgG antibodies were detected in 65 (33.0%) samples, on 14 (56.0%) farms. Females, animals older than 24 months, animals of small herds, and animals originating from south-western parts of Finland were more often T. gondii-seropositive than were males, younger animals, animals of larger herds, and animals originating from the north and east, respectively. Four (2.0%) of the sera, originating from three (12.0%) farms, tested Trichinella-seropositive with an in-house ELISA and a conservative cut-off for seropositivity. One farm had both T. gondii- and Trichinella-seropositive animals. Taken together, an infection source had been present on 16 (64.0%) farms, and 69 (35.0%) of the 197 farmed wild boars intended for human consumption had specific serological evidence of exposure to a zoonotic parasite.