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Reproductive performance, lifetime performance and removal hazard were studied in commercial herds in order to detect prolific sows at an early-stage. Reproductive performance measurements that we assessed were number of pigs born alive (PBA) per litter, weaning-to-first-mating interval and farrowing rate (FR). Lifetime performance measurements included lifetime average PBA and lifetime average nonproductive days. In total, 213,514 parity records and 47,024 lifetime records of 96 herds were included. Sows were categorized into three groups based on the lower and upper 25th percentiles of PBA in parity 1:8 pigs or fewer, 9–12 pigs and 13 pigs or more. The herds were classified into high- and low-performing herds on the basis of the 50th percentile of pigs weaned per mated female per year. To compare the measurements between the sow groups taking account for the herd productivity groups, multivariate and single response models were applied to reproductive performance from first-farrowing and lifetime performance, respectively. A hazard model was fitted to survival data. Sows having 13 or more PBA in parity 1 had 1.0–1.4 more PBA per litter in all subsequent parities ( P < 0.05), 1.2–1.5% higher FR in parities 2–4 ( P < 0.05) and 3.4–3.7 higher lifetime average PBA than sows having 8 or lower PBA ( P < 0.01). However, there were no differences between the sow groups for weaning-to-first-mating interval in any parity ( P > 0.05). There were two-way interactions between the sow and herd groups for FR in parity 2 ( P = 0.01) and lifetime average nonproductive days ( P = 0.046). In low-performing herds, sows having 13 or more PBA in parity 1 had 3.9% higher FR at their next farrowings than sows having 8 or fewer PBA ( P < 0.05), although no such difference was found for high-performing herds ( P > 0.05). Sows in the low-performing herds with 13 or more PBA in parity 1 also had 2.3 fewer lifetime average nonproductive days than sows having 8 or fewer PBA ( P = 0.01), although again no similar difference was found for high-performing herds ( P = 0.96). The removal hazards for sows having 13 or more PBA in parity 1 were lower than those for sows having 8 or fewer PBA ( P < 0.01), with no difference in hazards between the herd groups ( P = 0.62). In conclusion, PBA in parity 1 may help predict a prolific sow or low PBA sow. [ABSTRACT FROM AUTHOR]

Objectives were to determine climatic and production factors associated with abortions in commercial swine herds and to compare the reproductive performances and culling patterns between aborting and non-aborting females that were re-inseminated. There were 309,427 service records analyzed for 56,375 females entered into 100 herds. Climate data were obtained from 21 weather stations located close to the herds. Mean daily average temperatures (Tavg) for the 21-day pre-mating period for each female were combined with the female's reproductive data. Generalized linear model assessments were conducted for abortion risk per service. Abortion risk per service (±SE) was 0.7 ± 0.06%, and mean value of Tavg (range) was 15.0 °C (−10.7 to 32.7 °C). Risk factors associated with an increased abortion risk per service were greater numbers of parities, delivering more stillbirth fetuses, greater mean Tavg for the 21-day pre-mating periods and re-servicing of females that did not get pregnant at the first servicing ( P < 0.05). Abortion risk per service for parities 1–5 increased by 0.1–0.3% when the Tavg increased from 20 to 30 °C ( P < 0.05), but there were no such associations for parities 0 and 6 or greater ( P ≥ 0.37). Aborting re-serviced females had 0.4 fewer pigs born alive than non-aborting re-serviced females ( P < 0.05). Also, 64.6% of all aborting females were culled for reproductive failure, compared with only 23.4% of non-aborting females. In conclusion, producers should closely monitor females at greater risk of aborting and apply more advanced cooling systems. [ABSTRACT FROM AUTHOR]

Abstract: Our objective was to quantify the associations between climatic factors and a death occurrence of peripartum pigs from 16 to 19 weeks after successful service during hot and humid or cold seasons. The study used lifetime records of 93,837 females entered into 98 Japanese commercial herds from 2003 to 2007. The climate data were obtained from 21 weather stations close to the studied herds. Average daily maximum (HT) and minimum temperature (LT), and relative humidity for week 15 of gestation for each pregnant pig were coordinated with the respective pig's performance data. Multilevel logistic regression models were applied to two of the three separate datasets. One dataset included females due to farrow during the hot and humid season (June–September), and another comprised females due to farrow during the cold season (December–March). Of the 8381 females that died throughout the year, 11.5% of pregnant pigs died between 16 and 17 weeks after service, and 44.3% of farrowed females subsequently died from 16 to 19 weeks after service. Mean (ranges) HT in the hot and humid season and LT in the cold season were 28.7 (13.4–39.8)°C and 1.6 (−14.8 to 17.6)°C, respectively. Means of relative humidity in the hot and humid season and cold season were 73.6 (35–98)% and 64.9 (21–99)%, respectively. In the hot and humid season, a higher HT was associated with a higher occurrence of death for parity 0–1 females (P <0.05), but not for parity 2 or higher sows (P ≥0.38). The odds ratio was 1.030 (95% confidence intervals: 1.005–1.056) for HT in parity 0–1 females. Also, higher relative humidity was associated with a higher occurrence of death for parity 0–3 females (P <0.05), but not parity 4 or higher sows (P ≥0.21). In the cold season, a higher occurrence of death of parity 4 or higher sows was associated with lower LT (P <0.05). Also, the occurrence of death of parity 6 or higher sows was associated with higher relative humidity in the cold season (P <0.05). For parity 0–3 females, there were no associations between the occurrences of death and either LT or relative humidity during the cold season (P ≥0.11). Therefore, it is recommended to install cooling systems and thick insulation to prevent increases in occurrences of pig deaths due to HT or LT. [Copyright &y& Elsevier]

The objectives of this study were to determine the associations between climatic factors and production factors for returns to service of female pigs during summer and to quantify the associations between these factors and occurrences of returns to service. The factors that were assessed were as follows: maximum temperature (HT), relative humidity, age of gilts at first mating, parity, weaning-to-first-mating interval (WMI), and lactation length. The study analyzed records of 18,307 gilts in 99 herds and 78,135 parity records of 56,322 sows in 103 herds; all the females were first-serviced between June and September, 2007 to 2009. Average daily HT and relative humidity for 15 days post-service of a female were obtained from 21 local weather stations and coordinated with the performance data of the respective local herds. The returns to service were categorized into three groups: regular returns (RRs: 18–24 days), irregular returns (IRs: 25–38 days), and late returns to service (LRs: 39 days or later). Two-level mixed-effects models were applied to the data by using a herd at level 2 and an individual record at level 1. In mated gilts, the occurrences (%) of RRs, IRs, and LRs were 4.8%, 1.8%, and 5.3%, respectively. In mated sows, the respective occurrences were 3.3%, 1.8%, and 4.2%. Mean values (ranges) of HT and relative humidity were 28.4 °C (13.6 °C–39.8 °C) and 73.4% (35.0%–98.0%), respectively. In gilts, as HT increased from 25 °C to 30 °C, the occurrence of RR increased from 3.7% to 4.4% (P < 0.05). However, there was no association between the occurrence of RR and either relative humidity (P = 0.17) or age at first mating (P = 0.23). In addition, there were no associations between the occurrences of either gilt IR or LR and HT (P ≥ 0.05), relative humidity (P ≥ 0.46), or age at first mating (P ≥ 0.32). In sows, greater occurrences of RRs, IRs, and LRs were associated with higher HT, lower parity, and a WMI of 7 days or longer (P < 0.05), but they were not associated with relative humidity (P ≥ 0.62) or lactation length (P ≥ 0.13). The occurrence of RRs in sows of all WMI groups increased 1.22 (1.045) times for each 5 °C increase in HT. For sows with WMI 0 to 6 days, each 5 °C rise in HT increased the occurrence of IRs and LRs by 1.36 (1.065) and 1.27 (1.055) times, respectively. However, there was no association between increased HT and occurrences of IRs or LRs for sows with WMI 7 days or longer (P ≥ 0.38). Therefore, in order to prevent returns to service, it is recommended that producers apply cooling management for females during the post-service periods in summer. [ABSTRACT FROM AUTHOR]

Abstract: The objective of the present study was to quantify the associations between age at first mating (AFM) in gilts and the climatic factors of photoperiod (PP; h), number of hot days (HD) and relative humidity for different herd productivity groups. This study used records of 37,362 gilts born in 2007 and 2008 in 101 Japanese herds, which were classified into high-performing and ordinary herds based on the pigs weaned per mated female per year. The climate data were obtained from 21 weather stations. The HD was defined as the number of days that achieved a maximum temperature >25°C. Average values of daily PP, relative humidity and HD from day 91 to 150 after birth of a gilt were coordinated with the respective gilt performance data. Two-level mixed-effects models were applied to the data by using a herd at level 2 and a gilt at level 1. Mean AFM (ranges), PP, HD and relative humidity were 247.9 days old (152–364 days old), 12.2h (9–15h), 18.7 days (0–60 days) and 68.4% (48–87%), respectively. Delayed AFM was associated with decreased PP, more HD and being in an ordinary herd (P <0.05), but not with relative humidity. As PP rose by an hour, the AFM in high-performing herds decreased by 1.13 days rather than that in ordinary herds. It is possible that AFM in replacement gilts could be hastened by improving light control and cooling management during hot days. [Copyright &y& Elsevier]

Abstract: The objective of the present study was to quantify the associations between climate data and either weaning-to-first-mating interval (WMI) or adjusted 21-day litter weights of sows during summer for different herd productivity groups. This study was conducted using 87,428 parity records of 61,558 sows farrowed between June and September in 2007, 2008 and 2009, in 103 Japanese herds mostly located in humid subtropical areas. The 103 herds were classified into high-performing herds and ordinary herds by the basis of the upper 25th percentile of pigs weaned per mated female per year, averaged over the three years. The climate data were obtained from 21 weather stations of the Japan Meteorological Agency. Average values of the daily maximum temperatures (HT), average daily relative humidity (RH) and temperature-humidity index (THI) for 21 days after the farrowing date of a sow were coordinated with sow performance data from a recording system. Two-level mixed-effects models were applied to the data by using a herd at level 2 and an individual record at level 1. Mean values (ranges) of HT, RH and THI were 27.8°C (17.3–36.0°C), 74.6% (57.3–90.9%) and 22.2°C (13.0–27.4°C), respectively. Higher HT, RH and THI were associated with higher WMI and lighter adjusted 21-day litter weights (P<0.05). High-performing herds had lower WMI and heavier adjusted 21-day litter weights than ordinary herds at any HT, RH and THI (P<0.05). The WMI of sows in high-performing herds did not increase as much as those in ordinary herds when HT or THI increased. For example, as HT increased from 25 to 35°C, WMI of sows in high-performing herds increased by 0.3 days, whereas those in ordinary herds increased by 0.8 days. Also, when HT, RH or THI increased, parity 1 sows showed greater increase in WMI than parity 2 or higher sows (P<0.05). For instance, as THI increased from 15 to 25°C, WMI in parity 1 sows increased by 0.9 days, whereas those in parity 2 or higher sows increased by only 0.3 days. In conclusion, high-performing herds alleviate the negative effects of humid subtropical summer climates on WMI or adjusted 21-day litter weight more than ordinary herds. The parity 1 sows were more sensitive to such summer changes in climate than parity 2 or higher sows. Therefore, it is recommended in particular for parity 1 sows that producers practice cooling management during summer. [Copyright &y& Elsevier]

The objective of the present study was to investigate culling guidelines for gilts and sows in Japanese commercial herds and to compare differences between culling guidelines and actual culling practices in different herd productivity groups. A questionnaire survey was undertaken to obtain information on culling guidelines in 115 commercial swine herds that participated in the PigCHAMP data-share program. The questionnaire included questions on guideline values for culling intervals and the number of conception failure occurrences that would trigger a culling decision to be made. Ninety-two of the 115 herds (80.0%) returned appropriate data for the study and were included in the present study. In addition to questionnaire data, culling data regarding the actual culling intervals and number of reservices for gilts and sows culled during 2007 to 2008 were also obtained for the same herds from a PigCHAMP database. Culled gilts and sows were divided into 4 female groups on the basis of the stages of their reproductive life when they were culled: unmated gilts, mated gilts, unmated sows, and mated sows. Culling intervals in unmated gilts and sows were denned as the number of days from birth or weaning to culling, respectively, whereas in mated gilts and sows culling intervals were the number of days from last service to culling. Three herd productivity groups were formed on the basis of the upper and lower 25th percentiles of pigs weaned mated female"1 yr"1: high-, intermediate- or low-performing herds. For unmated gilts and sows actual culling intervals were 15 d shorter than the guideline culling intervals in the surveyed data submitted by producers (P < 0.05). This shorter actual culling period for unmated gilts and sows did not vary significantly between herd productivity groups in any parity. However, for mated gilts and sows the actual culling intervals were at least 30 d longer than the guideline culling intervals (P < 0.05). Guideline and actual culling intervals for mated gilts and sows were at least 10 d shorter in high-performing herds than in low-performing herds (P < 0.05). High-performing herds had lower proportions of sows culled after the second reservice than intermediate- or low-performing herds in parity groups 0 to 5 (P < 0.05). In conclusion, culling guidelines for mated sows differed between herd productivity groups, and culling guidelines for mated gilts and sows were not strictly followed in any herd group in the commercial herds. [ABSTRACT FROM AUTHOR]

Abstract: The objectives of the present study were to investigate the relationship between number of pigs born dead (PBD) and both post-farrowing performance and culling risk in sows, and to determine the repeatability of PBD within sow. The present study used 256,527 parity records of 51,907 sows on 110 commercial farms. Five groups for PBD were categorized: PBD 0, 1, 2, 3 and ≥4 pigs. Linear mixed-effects models were used to analyze the data. Variance components analysis was separately conducted for three groups based on parity at culling. Mean value (±SEM) of PBD was 1.1±0.01 pigs. Relative frequency of PBD 0, 1, 2, 3 and ≥4 pigs were 44.7, 24.8, 14.6, 7.5 and 8.4%, respectively. The relative frequency of PBD ≥4 pigs increased from 4.2 to 14.4% as parity increased from 2 to ≥6, whereas the frequency of PBD ≥4 pigs in parity 1 was 6.0%. Sows with PBD ≥4 pigs had 3.4% lower subsequent farrowing rate than those with PBD 0 pigs (P <0.01). In parities ≥3, sows with PBD ≥4 pigs had fewer pigs born alive at subsequent parity than those with PBD 1 pigs (P <0.01). However, in parities 1 and 2, no differences were found between the PBD groups in number of pigs born alive at subsequent parity. No difference was also found between the PBD groups in their subsequent weaning-to-first-mating interval. At each farrowed parity, culling risk for sows increased as PBD increased (P <0.01). Furthermore, the values of the repeatability of PBD in sows culled in parities 2–5, 6–7 and ≥8 were relatively low, 0.14, 0.16 and 0.15, respectively. In conclusion, culling for low-parity sows based on PBD is not justified as the value of repeatability of PBD is low. Additionally, assisted farrowing is recommended for high-parity sows and parity-1 sows to reduce the PBD. [Copyright &y& Elsevier]

Abstract: The objectives of this study were to measure culling rate and mortality rate of boars; to compare boar life day (BLD: days from birth date to removal date), boar herd life day (BHLD: days from herd entry date to removal date) and herd entry age of boars between high-performing herds and ordinary herds (herd groups); to examine herd measurements for BLD, BHLD and boar age at herd entry; and to observe removal patterns and survival curves for boars by herd groups. This study used 2474 records of individual boars born in 108 herds from 2000 to 2003. Two herd groups were formed on the basis of the upper 25th percentile of pigs weaned per mated female per year (2001–2005). Mixed-effects models and survival analysis were performed. Means of BLD and BHLD (±S.E.M.) were 984±9.5 and 781±8.4d, respectively. Annualized culling rate and mortality rate were 0.411 and 0.035 boars per 365 BHLD, respectively. Boars in high-performing herds had 51 higher BLD and 62 higher BHLD than those in ordinary herds (P <0.01). High-performing herds had 32d lower entry ages than ordinary herds (P <0.01). Herd measurements such as herd mortality and herd size were not associated with both BLD and BHLD. The hazards in survival analysis were associated with herd groups (P <0.05). Measurements in the present study provide benchmarks for boar removal in commercial herds. [Copyright &y& Elsevier]

Abstract: The objectives of this study were to investigate the associations of weaning-to-first-mating interval (WMI) groups with reproductive performance, to determine the repeatability and the correlation coefficients in WMI groups between consecutive parities, and to investigate factors associated with the proportion of sows having WMI 4–6 days. This study was conducted using 55,690 parity records of 11,991 sows born during 1999 in 94 herds. Five groups of WMI were formed: 0–3, 4–6, 7–20, 21–27, and ≥28 days. The correlation and the repeatability of the WMI groups were determined using correlation analysis and variance component analysis. Mixed-effects models were used to analyze the associations of WMI groups with reproductive performance, and the associations of parity, lactation length (LL), and nursing piglets with the proportion of sows having WMI 4–6 days. The overall proportion of the WMI 4–6 days was 82.3%. Sows with WMI 4–6 days had the highest farrowing rate, and had more pigs born alive than those with WMI 7–20 days (P <0.01). At each farrowed parity, sows with WMI 4–6 days had higher parity at removal than those with WMI 7–20 days (P <0.01). The repeatability of the WMI groups was low (0.08), and the correlation coefficients of WMI groups between consecutive parities were also low (0.10≤ r ≤0.18; P <0.01). More than 85.9% of sows with WMI 4–6 days were mated on 4–6 days postweaning at subsequent parity. Meanwhile, 65.8–83.9% of sows with WMI 0–3 or ≥7 days were also mated on 4–6 days postweaning at subsequent parity. Additionally, sows with parity ≥2, LL 24–28 days, and 9–10 nursing piglets were more likely to have WMI 4–6 days (P <0.01). In conclusion, sows having any WMI were more likely to be mated on 4–6 days postweaning at subsequent parity, and sows mated on 4–6 days had higher reproductive performance and higher longevity. Increased LL may increase the proportion of sows having WMI 4–6 days. [Copyright &y& Elsevier]

Abstract: The objectives of this study were to characterize sows having high lifetime efficiency and high longevity (HE–HL), to examine the relationship between lifetime measurements, and to determine the association between the sows and herd productivity. This study was conducted by obtaining sow data with 66,262 parity records of 13,786 sows born during 1999 and herd data with mean measurements of 4-year records from 2000 to 2003 in 92 herds. Sow lifetime efficiency was defined as the sum of pigs born alive in lifetime divided by the sow life days and multiplied by 365 days. Sows were categorized into three sow groups based on the upper 25 percentile of the lifetime efficiency and parity at culling ≥6. The three groups were sows having 1) the upper 25 percentile of the lifetime efficiency and parity at culling ≥6 (HE–HL sows), 2) less than the upper 25 percentile of the lifetime efficiency and parity at culling ≥6 (OE–HL sows), and 3) parity at culling ≤5 regardless of lifetime efficiency (LL sows). Mixed-effects models were used to compare reproductive performance between the three sow groups and to identify factors associated with a proportion of a HE–HL sow in the herd. Correlation analyses were done between lifetime performances in sows and between herd productivity measurements and the proportions of three sow groups in the herd. The proportions of HE–HL, OE–HL, and LL sows in 13,786 sows were 21.8%, 24.5%, and 53.7%, respectively. Lifetime efficiency was correlated with parity at culling (r =0.76; P <0.01) and nonproductive days per parity (r =−0.46; P <0.01). From first parity to the end, HE–HL sows had the greatest numbers of pigs born alive, the highest farrowing percentage, and the shortest nonproductive days per parity (P <0.01). Sows aged between 186 and 227 days at first mating were 1.09 to 1.11 times as more likely to become a HE–HL sow as those aged between 249 and 269 days at first mating (P <0.05). Of the 92 herds, mean proportion of HE–HL sows was 23.5%, and the proportions ranged from 0 to 57.6%. A higher proportion of HE–HL sows and a lower proportion of LL sows in the herd were correlated with more pigs weaned per mated female per year (P <0.01). In conclusion, HE–HL sows had high efficiency from the first parity to the end, which was attributed to herd productivity. [Copyright &y& Elsevier]

Abstract: This study investigated the associations of the number of services, reservice intervals (RI), parity, and weaning-to-first-mating intervals (WMI) with farrowing rate and pigs born alive (PBA) on commercial farms. The selected 117 farms included 115,442 service records and 93,867 farrowing records in 54,502 female pigs (females). A service was defined as one or more mating events within a 10-day time period of estrus. The number of services was categorized into three groups: non-return to service, first reservice, and second or later reservice. The RI was divided into 8 seven-day interval groups from 11 to 66 days and a group of 67–150 days. The effects of the number of services, RI, WMI, and parity on farrowing rate and PBA were analyzed by using the mixed-effects models. The frequency distributions of non-return to service, first reservice, and second or later reservice groups were 88.6, 9.7, and 1.7%, respectively. Farrowing rate decreased by approximately 18% with each service (P <0.05). Reserviced females exhibited a different reproductive performance as compared to non-return to service females depending on parity and WMI. In the non-return to service group, sows with WMI 7–12 days had the lowest farrowing rate (P <0.05). Meanwhile, in the first and second or later reservice groups, no differences between the WMI groups were found in farrowing rate. At parity 1 and 2, the first reservice group had the most PBA (P <0.05). However, at parity 0, 3–5, and ≥6, no differences between the number of service groups were found in PBA. In the WMI 0–6 and 7–12 day groups, the first reservice group had the most PBA (P <0.05). The mean of RI was 44.5±0.28 days in 13,183 reservice records. RI decreased from 47.4 to 39.2 days as parity increased from 0 to ≥6 (P <0.05). The frequency distributions of the RI 18–24, 39–45, and 67–150 days were 39.3, 12.4, and 18.8%, respectively. Gilts had lower proportions of the RI 18–24 days and higher proportions of RI 67–150 days than sows at parity 3–5 (P <0.05). No differences between RI groups were found in farrowing rate and PBA. Increasing farrowing rate in non-return to service females and minimizing RI in females at low parity improved herd productivity. [Copyright &y& Elsevier]

Abstract: This study investigated relationships between herd age structure and herd productivity in breeding herds; it also investigated a pattern in parity proportions of females over 2 years and its relationship with herd productivity in commercial swine herds. This study was based on data from 148 commercial farms in North America stored in the swine database program at the University of Minnesota. The primary selection criterion was fluctuations in breeding-female pig (female) inventories over a 2-year interval. Productivity measurements and parity proportions of females were extracted from the database. A 24-month time-plot in proportions of Parity 0 and Parities 3–5 females (mid-parity) was charted for each farm. Using these charts, a change in proportions of Parity 0 and mid-parity for each farm was categorized into patterns: FLUCTUATE (Parity 0 and mid-parity proportion lines crossed) or STABLE (the two proportion lines never crossed). Higher proportions of mid-parity sows were correlated with greater pigs weaned per female per year (PWFY; P &#60; 0.01). Farms with a FLUCTUATE (73% of the 148 farms) pattern had lower PWFY than those with a STABLE pattern (P &#60; 0.01). The STABLE farms had higher proportions of mid-parity sows, higher parity at culling, higher frequency of gilt deliveries per year, and lower replacement rate than the FLUCTUATE farms (P &#60; 0.01). In conclusion, maintaining stable subpopulations with mid-parity and Parity 0 are recommended to optimize herd productivity. [Copyright &y& Elsevier]

Examines factors that affect farrowing rate at sow and herd levels on early weaning farms. Analysis of database containing farrowing records from commercial farms; Parity, farrowing season and lactation length; Feed intake during lactation; Reproductive efficiency.

Investigates the effects of gestational energy intake on glucose tolerance in late gestation and midlactation, luteinizing hormone characteristics during lactation and postweaning in swine. Individual gestation stall for pregnant gilts; Conduction of glucose tolerance test; Analysis of plasma concentrations; Serum concentrations; Analysis by Greater Linear Method.

Investigates the influence of average daily feed intake and feed intake patterns during lactation on various reproductive parameters of sows located on commercial farms in the United States. Enrollment of sows using the PigChamp production information; Collection of data; Categorizing daily feed intake during lactation; Analysis of parity.

High temperature is an environmental factor that impairs sow fertility. In this study, we identified the critical weeks for heat stress effects on aspects of fertility performance, namely weaning-to-first-service interval (WSI) and farrowing rate (FR). We also examined the threshold temperatures above which the fertility performance deteriorated and whether there were any differences between parities regarding heat stress effects or thresholds. Performance data of sows in 142 herds from 2011 to 2016 were matched to appropriate weekly averaged daily maximum temperatures (T max ) from weather stations close to the herds. Two types of ratios (i.e. ratio for WSI and odds ratio for FR) were used to identify the critical weeks for heat stress by comparing the respective measures for two sow groups based on T max in different weeks around weaning or service events. The ratios for WSI were calculated between groups of sows exposed to T max ≥ 27 °C or <27 °C in each week before weaning, with the T max cutoff value based on a recent review study. Similarly, the odds ratios for FR for the two groups were calculated in weeks around service. The weeks with the largest differences in the fertility measures between the two T max groups (i.e. the highest ratio for WSI and the lowest odds ratio for FR) were considered to be the critical weeks for heat stress. Also, piecewise models with different breakpoints were constructed to identify the threshold T max in the critical week. The breakpoint in the best-fit model was considered to be the threshold T max. The highest ratios for WSI were obtained at 1 to 3 wk before weaning in parity 1 and 2 or higher sow groups. The threshold T max leading to prolonged WSI was 17 °C for parity 1 sows and 25 °C for parity 2 or higher sows. Increasing T max by 10 °C above these thresholds increased WSI by 0.65, and 0.33 to 0.35 d, respectively (P < 0.01). For FR, the lowest odds ratios were obtained at 2 to 3 wk before service in parity 0, 1, and 2 or higher sow groups. The threshold T max leading to reductions in FR was 20, 21, and 24 to 25 °C for parity 0, 1, and 2 or higher sow groups, respectively. Increasing T max by 10 °C above these thresholds decreased FR by 3.0%, 4.3%, and 1.9% to 2.8%, respectively (P < 0.01). These results indicate that the critical weeks for heat stress were 2 to 3 wk before service for FR and 1 to 3 wk before weaning for WSI. The decreases in fertility performance in parity 0 to 1 sows started at temperatures 3 to 8 °C lower than in parity 2 or higher sows. [ABSTRACT FROM AUTHOR]

Highlights • 1% of sows were removed due to prolapses. • 60% of prolapse cases were removed during first 0–4 weeks after farrowing. • Sows with gestation of 113 days or less were at risk of having a prolapse. • High parity sows were at high risk of having uterine prolapses. • Sows farrowing two or more stillbirths were at risk of having rectal prolapses. Abstract Prolapses in sows are an emerging concern in pig production. The objectives of this study were to estimate the incidence rate of prolapses and to determine risk factors associated with prolapse occurrences. Data included 905,089 service records in 819,754 parity records of 155,238 sows from 144 swine herds in Spain. Producers were required to record a removal reason, including type of prolapse. A 1:4 matched case-control study was carried out to investigate prolapse risk factors, and piecewise exponential models were applied to the data. The following factors were assessed: parity, number of services, service season, weeks after service, prior gestational length, total number of piglets born, and number of stillborn and mummified piglets. Almost 1% of sows (0.8%) were removed due to prolapses (95% confidence interval: 0.76, 0.85), and the annualized incidence rate for all prolapse cases was 3.8 cases per 1000 sow-years (95% confidence interval: 3.59, 4.01). Significant factors were the 16th week after service, being in parity 3 or higher, re-service, servicing in summer, autumn or winter, shorter gestational length, fewer piglets born and more stillborn piglets (P ≤ 0.04). For example, the prolapse incidence was 30.6 times higher at 16 weeks after service than during the first 14 weeks (P < 0.01). Also, 60.9% of 1198 prolapses occurred during the first 0 to 4 weeks after farrowing. The prolapse incidence was 1.5–1.8 times higher in parity 3 or higher sows than in parity 0 sows (P < 0.01), and 1.3 times higher in re-serviced sows than in first serviced sows (P = 0.02). It was also 1.3–1.5 times higher in sows serviced in summer, autumn or winter than in those serviced in spring (P ≤ 0.02), and 1.3–1.5 times higher in sows with a prior gestational length of 113 days or less than in sows with 114 days or more gestational length (P < 0.01). Lastly, the prolapse incidence rate was 1.2 times higher in sows with 11 or fewer piglets born than in sows with 12–16 piglets born (P = 0.04), and was also 1.4 times higher in sows with two or more stillborn piglets than in sows with no stillborn piglets (P < 0.01). However, there was no association between prolapse incidence and mummified piglets (P = 0.54). Consequently, producers should pay more attention to sows exposed to high risks, while trying to identify prolapse cases at an early stage. [ABSTRACT FROM AUTHOR]

Abortion occurrences disturb the projected production volume and increase non-productive days of female pigs. The objectives of the present study were (1) to define abortion occurrences including abortion rate and abortion risk, (2) to examine risk factors that were associated with abortions, (3) to determine repeatability of abortions and (4) to compare reproductive performance between aborting and non-aborting re-serviced female pigs. Datasets included 122,935 lifetime performance records and 630,363 mating performance records of females in 125 herds between 2008 and 2013 in Spain, Portugal and Italy. Annualized abortion rate was defined as the number of abortion records divided by the sum of the reproductive herd life days×365 days×100. Abortion risk per service was defined as the number of abortion records divided by the number of service records×100. Generalized linear models with random herd effect were applied to the data. Annualized abortion rate (±SE) and abortion risk per service were 3.0±0.05 and 1.2±0.01%, respectively. Factors for an increased abortion risk per service were parity 0 or parity 5 or higher, re-servicing, servicing in July and August, delivering stillborn fetuses in a previous litter and having prolonged weaning-to-first-mating interval (WMI; P <0.05). Gilts (parity 0) and sows in parity 5 or higher had 0.3% higher abortion risk than parity 1 sows ( P <0.05). Re-serviced females had 0.5% higher abortion risk than first-serviced females ( P <0.05). Females serviced in July and August had 0.4–0.5% higher abortion risk than those serviced in March and April ( P <0.05). Sows that had previously delivered stillborn fetuses subsequently had 0.1% higher abortion risk than those that had no stillborn fetuses ( P <0.05). Sows mated 7 days or more after weaning had 0.2% higher abortion risk than those mated 0–6 days after weaning ( P <0.05). Of the 7187 females that had aborted once, 4.1% experienced a second abortion in the same or a later parity. The repeatability of abortions was estimated to be 24.3–24.4%. Females that were reserviced after aborting had 0.6 lower total number of piglets born than re-serviced females that had not aborted ( P <0.05). However, there was no difference in farrowing rate or WMI between aborting and non-aborting re-serviced females ( P ≥0.11). It is recommended that producers closely monitor female pigs at risk of having an abortion in order to reduce non-productive female days. [ABSTRACT FROM AUTHOR]

Abstract: The objective of the present study was to compare management procedures and production factors between low-farrowing-rate herds (LFR herds) and the remaining herds (Non-LFR herds). The questionnaires were sent to the producers of 115 herds that use the same recording system. The questionnaire requested information about management procedures in 2008: (i) daily frequencies of estrus detection: once or twice a day; and (ii) the timing of first insemination. Data from 93 completed questionnaires (80.9%) were coordinated with the reproductive data of individual female pigs from the recording system. The data included 78,321 service records from 37,777 sows and gilts. Herds were classified into two groups on the basis of the lower 25th percentile of farrowing rate: LFR herds (76.5% or lower) and Non-LFR herds (76.6% or higher). At the herd level, a two-sample t-test, was used to compare the surveyed management procedures between the two herd groups. At the individual level, two-level mixed-effects models were applied, by using a herd at the level two and an individual record at the level one to determine associations between low farrowing rate and management procedures or production factors in gilts and sows. Gilt and sow models were separately constructed. Means (±SEM) of farrowing rate in LFR herds and Non-LFR herds were 71.3±0.92 and 85.5±0.54%, respectively. The lower farrowing rates of gilts and sows in LFR herds were associated with once-daily estrus detection, late timing of first insemination and single mating (P <0.05). In LFR herds that detected estrus only once a day, the farrowing rate decreased by 10.5% in first-serviced gilts and by 4.2% in reserviced sows compared with twice daily estrus detection (P <0.05). However, there was no such association in Non-LFR herds (P >0.05). The LFR herds had higher percentages of single-mated gilts and sows than Non-LFR herds (P <0.05). Fewer LFR herds than Non-LFR herds performed first insemination immediately after first estrus detection for gilts or by 6–12h for sows (P <0.05). In order to improve the farrowing rate in LFR herds, we recommend detecting estrus twice a day and performing first insemination earlier after first estrus detection; immediately for gilts and by 6–12h for sows. Additionally, increasing the percentage of multiple inseminations can effectively improve the farrowing rate. [Copyright &y& Elsevier]

• Lameness removal accounted for 4.3 % of 135,548 sows in 134 Spanish breeding herds. • Removal incidence was 33 times higher in week 5 after farrowing than in week 0. • The incidence was 5 times higher in weeks 4−5 after servicing than in weeks 0−1. • Re-serviced sows had 2 times higher removal incidence than first serviced sows. • Lame sows had delayed post-weaning estrus and smaller litter size than non-lame sows. Lameness is a major reason for sow removal in breeding herds. Increased removal occurrences for lameness decrease reproductive efficiency and increase welfare concerns. Therefore, the objectives of this study were to estimate the incidence rate of removal due to lameness, and to investigate the longevity and reproductive performance of sows removed due to lameness. Poisson regression models were applied to a cohort dataset of 137,907 sows in 134 herds located in Spain. The Wilcoxon rank sum test was used to compare the performance of sows removed due to lameness and their controls in one-to-two matched case-control datasets. Removal due to lameness accounted for 4.3 % of all removed sows, and the incidence rate was 19.6 cases per 1000 sow-years (95 % confidence interval: 15.03, 25.51). The majority (70.4 %) of those removed were farrowed sows, whereas only 29.6 % were serviced sows. In farrowed sows, a higher incidence of removal due to lameness was associated with weeks 4–9 after farrowing, higher parity and winter farrowing (P < 0.01). The removal incidence was 24.7–33.1 times higher in weeks 4–9 after farrowing than during the first week after farrowing (P < 0.01). It was 1.3–1.6 times higher in parity 4−5 than in parity 1, and 1.3 times higher for winter farrowing than for summer farrowing (P < 0.01). In contrast, the factors associated with removal due to lameness with serviced sows were weeks 4−5 after service and being re-serviced (P < 0.01). The service sow removal incidence was 4.7 times higher in weeks 4−5 after servicing than during the first 2 weeks after servicing (P < 0.01). Also, it was 2.2 times higher in re-serviced sows than in first serviced sows (P < 0.01). However, removal in serviced sows was not associated with parity (P = 0.10) or service season (P = 0.39). In the case-control datasets, the sows removed due to lameness had higher weaning-to-first-mating interval (means: 6.5 vs. 5.8 days), fewer piglets born alive (11.7 vs. 12.5 piglets) and lower parity at removal (3.4 vs. 4.9; P < 0.01) than sows removed for other reasons or non-removed sows. However, there was no difference in gilt age at first service between the case and control groups (P = 0.29). We recommend identifying sows showing early signs of lameness and treating them with pain medication until removal. The best time for removal would be at weaning when non-productive sow days start. [ABSTRACT FROM AUTHOR]

Abstract: To develop an efficient synthesis of type-II Si clathrates with low Na content (Na x Si136: x =0–24), various conditions for annealing the Zintl phase NaSi were examined. The addition of a pre-annealing process under vacuum at 250°C following the preparation of NaSi resulted in a decrease in the Na content of type-II Si clathrates from 4 to 2 when the pre-annealing duration ranged from 0 to 60h, while the volume fraction of type-II Si clathrate crystals in the synthesized specimens (type-II/(type-I+type-II+d-Si)) deduced by powder X-ray diffraction and Rietveld analysis was maintained at approximately 85%. These preparation techniques that enable the high-yield synthesis of semiconductive type-II Si clathrates open opportunities for the application of these substances to semiconductor devices. [Copyright &y& Elsevier]

Abstract: The objectives of the present study were to compare by-parity reproductive performance and lifetime performance of sows based on the differences in pigs born alive (PBA) between parity 1 and 2 (PBADIFF) and by summed PBA in parity 1 and 2. Lifetime and by-parity records were analyzed for 269,435 parity records of 47,837 sows farrowed in parity 1 and 2 in 101 commercial herds. The PBADIFF was calculated by subtracting the value of PBA in parity 1 from that in parity 2. Sows were categorized into nine groups based on PBADIFF, as follows: ≤−4, −3, −2, −1, 0, +1, +2, +3, or ≥+4 pigs. Four summed PBA groups were built on the basis of the lowest 25th percentiles, 26th to 50th percentiles, 51st to 75th percentiles, and the highest 25th percentiles of summed PBA in parity 1 and 2: ≤16, 17 to 20, 21 to 23, or ≥24 pigs. Annualized lifetime PBA was calculated as the sum of PBA in lifetime divided by the female life days multiplied by 365days. Mixed-effects models were used to compare performance measurements by PBADIFF and summed PBA groups. Relative frequencies (%) of PBADIFF ≤−4, −3, −2, −1, 0, +1, +2, +3 or ≥+4 pigs were 13.5, 6.3, 8.2, 10.1, 11.4, 11.7, 10.5, 8.5, and 19.8%, respectively. As PBADIFF increased from ≤−4 to ≥+4, PBA in parity 1 decreased, but PBA in parity 2 increased (P<0.05). From parity 3 to 6, there was only a slight difference in PBA between the PBADIFF groups (≤0.5 pigs; P<0.05), and no difference in farrowing percentage. Sows with PBADIFF −1 to +3 pigs had the highest annualized lifetime PBA, 2.5 to 2.8 pigs greater than sows with PBADIFF ≤−4 pigs (P<0.05). There was no difference between PBADIFF −1 to +3 pigs for consecutive performance from parity 3 to 6 or lifetime performance. In contrast to PBADIFF, sows with summed PBA ≥24 pigs had 2.1 to 2.8 pigs more PBA in parity 3 to 6 than those with summed PBA ≤16 pigs (P<0.05). Sows with summed PBA ≥24 pigs had higher farrowing percentage in parity 2 to 5 and 8.4 pigs more annualized lifetime PBA than those with summed PBA ≤16 pigs (P<0.05). Additionally, from parity 2 to 6, there were no differences in weaning-to-first-mating interval between the PBADIFF groups or between the summed PBA groups. In conclusion, summed PBA in parity 1 and 2 is a better measurement to predict lifetime performance of the sows than PBADIFF or decreased PBA. [Copyright &y& Elsevier]

Abstract: The objectives of this study were to assess the occurrence of decreased numbers of pigs born alive (PBA) in parity 2 (D-PBA) and to evaluate the importance of D-PBA sows and herds by analyzing against using the summed numbers of PBA in parity 1 and 2 (SPBA) and nonproductive sow days (NPD). The study assessed annual data from 2001 to 2005 from 106 herds, and sow data including 137,360 farrowing records of 68,680 sows farrowed in parity 1 and 2. D-PBA was defined as the same or fewer numbers of PBA in parity 2 than that in parity 1 at either the sow or herd level. Sows or herds were categorized into two groups: D-PBA or increased PBA in parity 2 (I-PBA). NPD was defined as the number of days that sows were neither gestating nor lactating in parity 1. Mixed-effects models were used to compare the reproductive performance between the two groups. Of the 68,680 sows, 49.5% had an occurrence of D-PBA. D-PBA sows had 0.3 pigs fewer SPBA than I-PBA sows, but those sows had 1.9days shorter NPD in parity 1 than I-PBA sows (P <0.05). Over the five years studied the average annual proportion of D-PBA herds was 16%. No differences were found between the D-PBA and I-PBA herds in the number of pigs weaned per mated female per year (PWMFY), SPBA or NPD in any year. Additionally, the PWMFY was not correlated in any years with either the proportions of D-PBA sows or the difference in PBA between parity 1 and 2. In conclusion, the occurrence of D-PBA does not appear to be a serious problem in Japanese swine herds studied. [Copyright &y& Elsevier]