Associations among individual gilt birth weight, litter birth weight phenotype, and the efficiency of replacement gilt production.

Selection for larger litter size has increased the number of low individual birth weight (BWi) pigs and produced sows with a repeatable low average litter birth weight phenotype (BWP). Using an average of 3.6 litters records per sow, BWP was established in 644 nucleus-multiplication sows producing replacement gilts in a large commercial operation and classified as low (L-BWP, <1.18 kg, n = 85), medium (M-BWP, ≥1.18 to ≤1.35 kg, n = 250), or high (H-BWP, >1.35 kg, n = 309) on the basis of a BWi of 1.18 kg below which there was a high risk of early mortality and the average BWi (1.35 kg) for the population. In subsequent litters, potential replacement gilts born to these sows (n = 7,341) received a unique identification tag that allowed the impact of BWi, BWP, and their interactions on the efficiency of replacement gilt production to be evaluated. Negative effects of BWi on mortality until day 4 after birth were confirmed (P < 0.05) and cumulative losses to weaning, to day 70 of age, and to final pre-selection at 165 d of age were affected (P ≤ 0.05) by the interaction between BWP and BWi. Among the 2,035 gilts for which records for selection efficiency and production to fourth parity were available, a lower BWi decreased the probability of gilts reaching pubertal estrus (P < 0.05) after 21 and 28 d of boar stimulation starting at 180 d of age, with no effect of BWP. Overall, neither BWi, BWP, nor their interaction affected age at puberty. After breeding, only the main effect of BWP affected productivity and retention in the sow herd. In parities 1 and 2, percent stillborn was higher in litters born to gilts from H-BWP compared with L-BWP dams (P < 0.05), and in parity 2, total born and born alive were lower in sows derived from H-BWP compared with other BWPs. There were no differences in retention based on BWP classes until parity 2, after which retention tended (P ≤ 0.09) to be lower in sows derived from H-BWP compared with L-BWP dams. These results provide evidence that sow BWP is an important factor in the overall efficiency of replacement gilt management. This study also confirms that effective gilt selection and pre-breeding management protocols support excellent sow lifetime productivity and mitigate the risk of a high BWP in the litter of origin affecting retention in the breeding herd.

Effects of flush feeding strategy before breeding on reproductive performance of modern replacement gilts: impacts on ovulation rate and litter traits.

AbstractThe effects of two feed levels offered during two estrous cycles before insemination were evaluated on the reproductive performance of gilts. A total of 93 gilts (PIC Hendersonville, TN) were individually housed and manually fed twice a day with 2.1 or 3.6 kg/d of a corn and soybean meal-based diet (3.15 Mcal ME/kg and 0.64% standardized ileal digestible lysine), during two estrous cycles before breeding (cycle 1, between first and second estrus; cycle 2, between second and third estrus). Gilts were weighed at the beginning of the experiment, at second and third estrus, and at slaughter (30.2 ± 1.2 d of gestation). Follicles were counted at second estrus, and the embryo-placental units and the corpora lutea were individually counted, measured, and weighed at slaughter. Gilts fed 3.6 kg/d had greater BW gain during cycle 1 and cycle 2 (P < 0.001; + 9.8 kg and + 10.0 kg, respectively) becoming heavier at second and third estrus (P < 0.001). At second estrus, gilts fed 3.6 kg/d had 1.6 more medium-large follicles (P = 0.074) but no difference in follicle size (P = 0.530) was observed. Gilts fed 3.6 kg/d in cycle 1 or cycle 2 had a greater ovulation rate at third estrus (P < 0.016) than those receiving 2.1 kg/d. Also, 3.6 kg/d in cycle 2 increased early embryo mortality (P = 0.006; 2.3 vs. 1.1 dead embryos) and consequently reduced total embryo survival (P = 0.002; 84.6 vs. 90.1%). Gilts fed 3.6 kg/d during cycle 1 had two more total embryos (P < 0.001; 17.2 vs. 15.1) and two more vital embryos on day 30 (P < 0.001; 16.7 vs. 14.5) in comparison with gilts fed 2.1 kg/d. The coefficient of variation for placental length was greater for gilts fed 3.6 kg/d during cycle 1 (P = 0.003). No further significant effects of feeding levels were observed on embryo and placental traits (P ≥ 0.063). These results suggest that the feeding level during the first cycle after pubertal estrus is crucial to set ovulation rate and potential litter size for breeding at next estrus. However, flush feeding gilts before insemination can negatively impact litter size by reducing embryo survival when breeding at third estrus.

Impact of feed intake in early gestation on maternal growth and litter size according to body reserves at weaning of young parity sows.

The effect of increasing the feed level (1.8, 2.5, and 3.2 kg/d) during early gestation in parity 1 (PO1) and parity 2 (PO2) sows on maternal growth and litter size was evaluated. A total of 361 sows were group-housed and fed a diet based on a corn-soybean meal (3.15 Mcal Metabolizable Energy (ME) per kg and 0.68% standardized ileal digestible lysine) from day 6 of gestation until day 30. Sows were weighed at weaning and on day 30 of gestation. Farrowing rate, number of total piglets born, piglets born alive, stillborn piglets, and mummified fetuses were recorded at farrowing. The effect of feed level on the total number of piglets born was also evaluated according to classes of body weight (BW), body condition score (BCS), backfat (BF), and caliper unit at weaning for each parity order. There was no evidence for significant effect of the interaction between feed level × parity on the variables related to maternal growth and reproductive performance (P ≥ 0.128). Greater feed levels linearly increased the gains in body condition (i.e., BW, BCS, BF, and caliper unit) between weaning and day 30 of gestation (P < 0.001). Farrowing rate was not influenced by the feed level (P ≥ 0.200) and parity (P ≥ 0.209). The number of total piglets born decreased linearly as the feed level increased (P = 0.041), whereas no evidences for differences were observed on piglets born alive among treatments (P ≥ 0.317), neither between parities (P ≥ 0.904). For PO1 sows, the total piglets born on BW classes (≤183 vs. >183 kg) and on classes of BF (≤11.5 vs. > 11.5 mm) were quadratically affected by the feed levels (P ≤ 0.041). In contrast, the number of total piglets born was marginally affected (linear; P ≤ 0.094) by the feed level in the different classes of BW, BCS, and caliper unit in PO2 sows. There was no evidence for differences for the interaction of feed level and classes of body condition (P ≥ 0.199) for PO2 sows. Similarly, no interactions between feed level and classes of BW, BCS, and BF at weaning were observed (P ≥ 0.233) for PO1 sows; however, the total piglets born were affected by an interaction between feed level and caliper unit class (P = 0.042). In conclusion, increased feed intake from day 6 of gestation until day 30 resulted in increased maternal BW gain but reduced the number of total piglets born. Furthermore, lighter and in a poor BCS PO1 sows at weaning produced fewer total born piglets with no benefits from greater amounts of feed.

Maternal nutrition during early and late gestation in gilts and sows under commercial conditions: impacts on maternal growth and litter traits1.

The effects of two different feeding levels, offered in two phases during gestation, on body measurements and litter traits were evaluated in 152 gilts and 551 sows. The treatments consisted of the combination of two gestation phases (phase 1-days 22 to 42; phase 2-days 90 to 110) and two feed amounts (1.8 or 3.5 kg/d). Females were weighed on days 22, 42, 90, and 110 of gestation. Born alive and stillborn piglets were weighed within 12 h of birth. Total placental efficiency (ratio between litter weight and total placental weight) was measured in 518 females. Variables concerning body measurements at days 42 and 90 of gestation were analyzed considering the effects of feed amount, parity order (PO) and its interaction as a 2 × 2 factorial arrangement. Body measurements at day 110 of gestation and litter traits were analyzed considering the effects of feed amounts in phase 1, feed amounts in phase 2, PO and their interactions, as a 2 × 2 × 2 factorial arrangement. As expected, BW, backfat, and caliper units were greater at days 42, 90, and 110 (P ≤ 0.006) for females fed 3.5 kg/d during the previous phase than those fed 1.8 kg. No differences were observed among feed levels in total number of piglets born, mummified fetuses, sum of born alive and stillborn piglets, and within-litter birth weight CV (P ≥ 0.118). The percentage of stillborn piglets was affected by a three-way interaction (feed level at phase 1 × feed level at phase 2 × PO). Gilts fed 1.8 kg/d at phase 1 and 3.5 kg/d at phase 2 had fewer stillborn piglets than the other females (P ≤ 0.004). Birth weight was not affected by feed levels (P ≥ 0.153); however, sows had heavier piglets than gilts (P < 0.001). Females fed 3.5 kg/d during phase 2 tended to have heavier litters (P = 0.054) than those fed 1.8 kg/d. Feeding a high level at phase 2 reduced the occurrence of lightweight piglets in gilts, but not in sows (feed level phase 2 × PO; P = 0.031). Total placental weight, average placental weight, and total placental efficiency were not affected by feed level at phase 1, feed level at phase 2 or interactions (P > 0.14). Sows had total placental weight and average placental weight greater (P ≤ 0.003) than gilts. In conclusion, increasing feed intake during phase 1, phase 2, or both phases resulted in increased maternal BW gain, without expressive effects on litter traits. Feeding 3.5 kg/d to gilts during phase 2 reduced the occurrence of lightweight piglets.

Optimizing timed AI protocols for Angus beef heifers: Comparison of induction of synchronized ovulation with estradiol cypionate or GnRH.

This study compared estradiol cypionate (ECP) or GnRH as ovulation inducers at the end of a timed AI (TAI) protocol in Angus heifers. On day 0, heifers (n = 415), between 22 and 24 months of age, were treated with an intravaginal 1 g progesterone (P4) insert and 2 mg of estradiol benzoate. On day 8, heifers had P4 removed, received 500 µg cloprostenol, and were randomized into two groups: ECP [n = 214; 0.5 mg of ECP on day 8] or GnRH [n = 201; 25 µg of GnRH analog licerelin acetate on day 10]. All heifers received TAI on day 10; 48-50 h after P4 insert withdrawal. Estrus was determined by removal of tail paint. Ovaries of heifers were evaluated by ultrasound on day 0 to determine CL presence (with CL = 213, without CL = 202) and on day 10 to measure preovulatory follicle size. Heifers were divided into three categories based on preovulatory follicle diameter: <8.5 mm (smaller than deviation), 8.5-10.9 mm, or ≥11 mm. Pregnancy diagnosis was performed 32 days after TAI. Heifers treated with ECP had greater expression of estrus than GnRH-treated heifers (93.9% vs 67.7%; P < 0.0001), regardless of CL presence at beginning of protocol. Heifers with CL at beginning of protocol had larger preovulatory follicle diameter (10.4 mm vs 9.6 mm; P = 0.0058) and greater pregnancy per AI (P/AI; 61.0% vs 50.5%; P = 0.032) than heifers without CL at day 0. In heifers with CL at day 0, GnRH treatment increased P/AI compared to ECP treatment (68.0% vs 54.9%; P = 0.0498). Expression of estrus was greater in ECP-treated than GnRH-treated heifers that had small (<8.5 mm; 77.1% vs 5.6%; P < 0.001) or medium-sized (8.5-10.9 mm; 98.4% vs. 61.7%) follicles, but not in heifers with large follicles (≥11 mm; 97.9% vs 98.3%). The P/AI was very low in both treatments for heifers with follicles <8.5 mm (ECP-14.3% vs GnRH-16.7%). In heifers with medium-sized follicles (8.5-10.9 mm), ECP treatment tended to increase P/AI compared with GnRH-treated heifers (62.9 vs 46.7%; P = 0.074). In contrast, P/AI was greater for GnRH-treated than ECP-treated heifers with large preovulatory follicles (≥11 mm; 79.7% vs 60.4%; P = 0.032). Thus, the optimal inducer of ovulation in a TAI protocol for beef heifers appears to depend on the presence of a CL at beginning of protocol (GnRH > ECP if CL present) and size of the preovulatory follicle, with ECP increasing expression of estrus and tending to increase fertility in heifers with medium-sized follicles but GnRH increasing fertility in heifers having large preovulatory follicles.

Virulence profiles of enterotoxigenic Escherichia coli isolated from piglets with post-weaning diarrhea and classification according to fecal consistency / Perfis de virulência de Escherichia coli enterotoxigênica isoladas de leitões desmamados com diarreia do Sul do Brasil e classificação das amostras de acordo com a consistência fecal

The aim of this study was to assess the frequency and association of virulence factors of Escherichia (E.) coli isolated from weaned piglets with diarrhea and to correlate it with fecal consistency. A total of 152 rectal swabs were collected from 25-40 day-old piglets with diarrhea, in farms of Southern Brazil. Phenotypical and molecular techniques were used for bacterial isolation, characterization and classification of enterotoxigenic E. coli (ETEC) pathotypes. Statistical analysis was carried out to determine the frequency of virulence factors and virotypes, of fimbriae F4, F5, F6, F18, F41 and toxins LT, STa, STb and STx2e. Out of 456 E. coli isolates, 287 (62.9%) samples showed significant growth of E. coli. Among them, 194 (67.6%) samples showed at least one virulence factor, indicating that ETEC is an important etiological agent of diarrhea in weaned piglets. Higher frequencies were found of fimbria F4 and F18 and enterotoxins LT, STa and STb. Significant association was found to F4, LT, STa and STb; between F18 and STa and STx2e; between F5 and LT, STa and STb. The most frequent virotypes were F18-STa, F4-LT-STa-STb, F4-STa, F4-LT-STb and F18-STa-STx2e. Beta-hemolysis was observed in 47.4% of samples and there was significant association between hemolytic samples and virulence factors F4, F18, STa and STx2e. Regarding fecal consistency, there was significant association of liquid feces and F4 fimbria, STa toxin and virotypes F4-STa and F4-F5-LT-STa-STb. Since there was significant association of ETEC and liquid feces in nursery piglets, it is important to prioritize the sampling of liquid feces for the diagnosis etiologic cause of diarrhea.

O objetivo deste estudo foi avaliar a frequência e associação de fatores de virulência de Escherichia (E.) coli isoladas de leitões desmamados com diarreia e correlacioná-la com consistência fecal. Suabes retais foram coletados em leitões com 25-40 dias de idade com sinal clínico de diarreia, em granjas do Sul do Brasil, totalizando 456 amostras. Foram utilizadas técnicas fenotípicas e moleculares para isolamento bacteriano, caracterização e classificação de patotipos de E. coli enterotoxigênica (ETEC). A análise estatística foi realizada para determinar a frequência de fatores de virulência e virotipos, de fímbrias F4, F5, F6, F18, F41 e toxinas LT, STa, STB e STx2e. Duzentas e oitenta e sete (62,9%) amostras apresentaram crescimento significativo de E. coli. Entre os quais, 194 (67,6%) amostras apresentaram pelo menos um fator de virulência, indicando que ETEC é um importante agente etiológico de diarreia em leitões desmamados. As frequências mais elevadas foram encontradas para as fímbrias F4 e F18 e enterotoxinas LT, STa e STb. Associação significativa foi encontrada para F4, LT, STa e STb; entre F18 e STa e STx2e; entre F5 e LT, STa e STb. Os virotipos mais frequentes foram F18-STa, F4-LT-STa-STb, F4-STa, F4-LT-STb e F18-STa-STx2e. Beta-hemólise foi observada em 47,4% das amostras e houve associação significativa entre amostras hemolíticas e fatores de virulência F4, F18, STa e STx2e. Quanto consistência fecal, houve associação significativa de fezes líquidas e fímbria F4, toxina STa e virotipos F4-STa e F4-F5-LT-STa-STb. A associação significativa da ETEC e fezes líquidas em leitões de creche, é importante para priorizar a amostragem de fezes com essa consistência para no diagnóstico etiológico da diarreia.

Influence of tail biting on weight gain, lesions and condemnations at slaughter of finishing pigs / Influência do canibalismo de cauda no ganho de peso, lesões e condenações ao bate de suínos em terminação

The present study assessed the association of tail-biting lesions in finishing pigs with weight gain, occurrence of locomotion or respiratory disorders and abscesses during finishing period, and carcass condemnation at slaughter. The study was carried out on 4 different farms. For each animal with a tail biting lesion, two control pigs were selected. The total number of animals in the study was 312, with 104 of them being tail-bitten. Tail lesions were classified according to the degree of severity into four scores: score 0 -normal tail withou lesion; score 1-3 - increasing lesion severity, and score 4 - healed lesions. Overall, the occurrence of severe tail lesions (score 3) varied from 55 to 73% of tail-bitten pigs among farms. On all farms, healing of tail lesions was observed in 95% to 100% of the animals at the evaluation performed within 41-43 days after the commencement of the study. In two out of the four evaluated farms, pigs with score of 3 showed lower weight gain (P<0.05) compared with score 0 pigs. Before slaughter, the occurrence of locomotion problems and nodules/abscesses was associated (P<0.05) with the presence of tail-biting lesions. At slaughter, tail-biting lesions were associated (P<0.05) with the presence of abscesses, lung lesions (pleuritis and embolic pneumonia) or arthritis in carcasses. Carcass condemnation was associated with the presence of tail-biting lesions (P<0.05). Overall, carcass condemnation rate was 21.4%, of which animals with tail-biting lesions accounted for 66.7% of condemnations. Among the animals diagnosed with cannibalism at farm level, only two had not healed their lesions at slaughter. The fact that there were a lot of carcass condemnations, despite the fact that tail-bitten animals had no more active lesions, suggests that different situations may be observed between the field and slaughter, reinforcing the need to analyze pigs both at farm and slaughter to allow proper assessment of losses related to tail biting. Collectively, the observations of the present study show that complications associated with tail-biting found in slaughterhouses are probably underestimating field prevalence.

O presente estudo avaliou a associação das lesões de canibalismo de cauda em suínos de terminação com o ganho de peso, ocorrência de problemas locomotores ou respiratórios e abscessos durante a fase de terminação, e condenação de carcaças ao abate. O estudo foi realizado em quatro granjas comerciais de suínos. Para cada animal com lesão de canibalismo de cauda, outros dois suínos na mesma baia foram selecionados como controle, totalizando 312 animais avaliados. As lesões de cauda foram classificadas de acordo com o grau de severidade em quatro escores: score 0 - cauda normal, sem lesão; escores de 1 a 3 - de acordo com o aumento da severidade da lesão, e escore 4 - lesões cicatrizadas. No total, suínos com lesões severas (escore 3) corresponderam a 55-73% dos animais com lesão de caudofagia. Em todas as granjas, a cicatrização das lesões de cauda foi observada em 95% a 100% dos animais na avaliação realizada entre 41-43 dias após o início do estudo. Animais com escore 3 apresentaram menor ganho de peso (P<0,05) quando comparados com animais de escore 0, em duas das quatro granjas avaliadas. Antes do abate, a ocorrência de problemas locomotores e de nódulos/abscessos foi associada (P<0,05) com a presença de lesões de caudofagia. Ao abate, as lesões de canibalismo de cauda foram associadas (P<0,05) com a presença de abscessos, lesões pulmonares (pleurite e pneumonia embólica) ou artrite na carcaça. A condenação de carcaça foi associada com a presença de lesões de canibalismo de cauda (P<0,05). A taxa de condenação de carcaças foi de 21,4%, sendo que os animais com lesões de canibalismo de cauda corresponderam a 66,7% dessas condenações. Dos animais diagnosticados com canibalismo de cauda, somente dois apresentavam lesões ativas ao abate. O aumento do número de condenações no abate nos lotes estudados sugere que diferentes situações sanitárias podem ser observadas a campo e ao abate, reforçando a necessidade de analisar os animais na granja e ao abate, a fim de permitir uma avaliação precisa das perdas associadas ao canibalismo de cauda. Coletivamente, as observações do presente estudo sugerem que as complicações associadas com o canibalismo da cauda verificadas no abate provavelmente representam uma subestimativa da prevalência encontrada nas granjas.

Factors associated with return to estrus in first service swine females.

Reproductive failure is a major factor contributing to the culling rate of swine females. As return to estrus is the most frequent reproductive failure, the study of factors associated with its occurrence can help to identify females with a predisposition to this failure. This study was run in a farm with a housing capacity of 1500 Agroceres PIC females in southern Brazil. Logistic regression models were run to determine the relative contribution of some factors to the probability of a sow returning to estrus. Return to estrus occurred in 27.8% (10/36) and 10.7% (50/469) of females remated after a previous reproductive failure and first service females, respectively. Females with a previous reproductive failure had 3.2-times higher odds (P=0.003) of returning to estrus than first service females. In first service females (n=469), higher odds (P<0.05) of returning to estrus were observed in parity order (PO) 0 (14.3%; 3.1-times), PO1 (20.6%; 4.9-times) and PO2 (12.7%; 2.7-times) compared to PO>2 (5.0%; reference class) females. Weaned females with ovarian cysts, detected during estrus, had 7.6-times higher (37.5%; 3/8) odds (P=0.012) of returning to estrus than females without cysts (8.3%; 28/338). In the model run with 330 weaned sows, the return to estrus rate was not affected (P>0.05) by the number of weaned piglets (7-9; 10; 11 and 12 piglets) but sows with a lactation length (LL) of 15-19 days had 3.5-times higher odds (P<0.05) of a return to estrus than sows with LL of 20-21 days. Return to estrus in weaned sows was also affected by the interaction between PO and body condition score (BCS) loss during lactation. Loss of more than 0.5 point in BCS resulted in higher odds (P<0.05) of returning to estrus in PO1 and PO2 but not in PO>2 sows. Accurate detection of estrus in gilts and adequate feed intake during lactation of first and second parity sows are suggested to reduce return to estrus rate in younger females. To avoid the detrimental effect of short lactations on reproductive performance options such as increasing the lactation length, split-weaning or skip-mating may be considered.

Reproductive performance of swine females re-serviced after return to estrus or abortion.

The objective of this study was to analyze reproductive performance in swine females re-serviced after return to estrus or abortion in comparison with females in first service (gilts or weaned females). Records used were obtained from four commercial sow herds in Brazil including 24,194 mating records from PigCHAMP research database. Three mating categories (first service in gilts or weaned sows, re-serviced after return to estrus and re-serviced after abortion) were considered for the analysis. The farrowing rate (FR) was less and return to estrus (RER), abortion rate (ABR) and total born (TB) were greater in the category re-serviced after return to estrus compared to first service category (P<0.05). The category re-serviced after abortion only differed from the first service category by a greater ABR (P<0.05). In gilts and PO2-5 females re-serviced after a return to estrus, the FR was less (72.0% and 83.2%) and RER was greater (22.3% and 12.5%) compared to first service PO2-5 sows (92.7% and 5.3%; P<0.05). A re-service after a return to estrus did not affect TB in PO > or =2 females (P>0.05) but resulted in less TB in gilts and greater TB in primiparous sows (P<0.05). In females re-serviced after a return to estrus the performance was similar (P>0.05) between the two intervals considered as regular return to estrus (18-24 days and 36-48 days). Among the intervals considered as irregular return to estrus, greater FR was observed in intermediate (25-35 days) than in early (11-17 days) or late (>48 days) intervals. The re-service after a return to estrus results in an impaired farrowing rate, with a greater impact on gilts than at older parities. Females re-serviced after abortion are more predisposed to the recurrence of this reproductive failure.

Time of ovulation and reproductive performance over three parities after treatment of primiparous sows with PG600.

Primiparous sows from a commercial pig farm in central Brazil were utilized to investigate the effect of post-weaning gonadotrophins (given during summer) on estrus, time of ovulation and reproductive performance over three parities. One group of sows (PG600) was treated with a combination of 400 IU equine chorionic gonadotrophin (eCG)+200 IU human chorionic gonadotrophin (hCG) (PG600) 24h after weaning (n=420), whereas the control group received saline (n=408). In a subset of sows (n=150), estrus was detected and time of ovulation was determined by transcutaneous ultrasound. Treatment with PG600 increased the percentage of primiparous sows in estrus within 10 days after weaning (94.8% versus 79.7%) and reduced the first weaning-to-estrus interval (5.3 days versus 8.0 days) relative to control sows (P<0.05). Although the duration of estrus was longer (P<0.05) in sows given PG600 (65.7 h versus 61.0 h), the interval from estrus to ovulation was not different (P>0.05) between PG600 and control sows (46.6 h versus 43.3 h). Treatment with PG600 did not affect (P>0.05) rates of return-to-estrus and farrowing over three parities, but it increased the number of total piglets born (P<0.05) in the second parity (11.2 versus 10.4), thereby minimizing the magnitude of second-litter syndrome. Culling rates from the first to the fourth parity were 26.7 and 24.5% (P>0.05) for PG600 and control sows, respectively. In conclusion, PG600 given 24 h after the first weaning reduced the weaning-to-estrus interval and increased the size of the second litter.

Risk factors for stillbirth and foetal mummification in four Brazilian swine herds.

The objective of this study was to identify the risk factors of stillbirth and foetal mummification in 565 farrowings of four commercial pig farms in Brazil. Stillborn piglets were observed in 31.3% of the litters and the stillborn risk was 5.6%. Mummified foetuses occurred in 42.1% of the litters and the mummification risk was 3.4%. The potential risk factors were included in multivariable logistic regression models as categories: herd (1-4); parity (1, 2-5 and >5); litter size (<10, 10-12 and >12 piglets); farrowing length (< or =3 or >3h); presence of mummified foetuses (yes or no); farrowing induction (yes or no); use of oxytocin (yes or no); use of vaginal palpation (yes or no); body condition score (<3, 3 and > or =4), and placental production index (PPI) (5) which was measured as the ratio of total foetal weight to total placental weight. Duration of farrowing and use of farrowing induction, oxytocin or vaginal palpation were not included in the model that investigated the risk factors of foetal mummification. Two models were used to investigate the risk factors of stillbirth, one with and the other without the inclusion of farrowing length. When compared to sows of parity 2-5, sows of parity >5 had 1.7- and 1.6-times higher odds (P<0.05) for stillbirth in the models with and without the inclusion of farrowing length, respectively. In both models, sows with more than 12 piglets/litter had 3.6-times higher odds of stillbirth occurrence compared to sows with less than 10 piglets (P<0.05). Sows with prolonged farrowing (>3h) had 2.0-times higher odds of stillbirth occurrence than sows with short farrowing (P<0.05). Sows with more than 12 piglets/litter had 14.5-times higher odds of mummification compared to sows with less than 10 piglets (P<0.05). Sows of parities 1 and >5 had 3.5- and 2.0-times, respectively, higher odds of mummification in comparison to sows of parity 2-5 (P<0.05). Sows with low PPI had 1.7-times higher odds of mummification compared to those with high PPI (P<0.05). A large litter, a high-parity and a prolonged farrowing increased the risk of stillbirth. The probability of having a mummified foetus was increased in very young and older sows, when having a large litter and a litter with a less efficient placenta.