Feed intake patterns of modern genetics lactating sows: characterization and effect of the reproductive parameters

BACKGROUND

Knowing the feed intake pattern during lactation of modern genetic sows is crucial because it allows to anticipate possible problems and maximize their performance. On the other side, electronic feeders permit real-time data to be available for a more accurate evaluation of sow eating behavior. This work aimed to characterize the feed intake patterns of lactating highly prolific sows and determine their effect on reproductive performance. A database of 1,058 registers of feed intake collected from a commercial farm was used to identify five consistent sets of clusters (feeding curves) using machine learning. In the second step, the five feeding curves were characterized into five patterns by high, medium and low feed intake during 0-6 d and 7-28 d of lactation: 1-HH, 2-MH, 3-HM, 4-MM and 5-LL.

RESULTS

The mean daily feed intake of all the sows was 6.2 kg (0.06 SEM) across the 5 patterns. As the pattern numbers increased from 1-HH, 2-MH, 3-HM and 4-MM to 5-LL, their mean daily feed intake decreased from 7.6 to 6.9, 6.4, 5.8 and 4.3 (0.06 SEM) kg, respectively (P < 0.01). Sows with Pattern 1-HH tended to have shorter weaning-to-first service interval (P = 0.06) and had a higher farrowing rate than those with Pattern 5-LL (P < 0.01). Furthermore, contrast analysis showed that sows with Patterns 1-HH and 2-MH tended to have more piglets weaned (P = 0.05) and lower preweaning mortality (P = 0.07) than those with Patterns 3-HM and 4-MM. Also, sows with Patterns 1-HH and 3-HM had fewer stillborn piglets and a lower percentage of stillborn piglets and mummies than those with Patterns 2-MH and 4-MM (P < 0.01).

CONCLUSIONS

This study indicates the importance of reaching Pattern 1-HH by rapidly increasing feed intake during early lactation and high feed intake during late lactation, which is associated with high weaning performance and subsequent reproductive performance of the sows. Also, the current study suggests that Pattern 1-HH is linked to good farrowing with a low percentage of stillborn piglets and mummies. Finally, it is critical for producers to timely identify a problem of sows' eating behavior and to make a prompt decision to intervene.

Factors associated with canine skin extensibility in toy poodles

To assess factors for canine skin extensibility, our study investigated associations between the dogs' skin extension index and the following factors, gender, age, neuter status, weight, coat color and six coat color related gene polymorphisms. Swab samples were collected from 69 toy poodles to extract DNA. The skin extension indices of the lower back and the neck were measured using the following formula: vertical height of the skin fold divided by body length multiplied by 100. The dogs' age, weight, gender, neuter status and coat color were also recorded, as well as polymorphisms of the following six selected coat color related genes, Melanocortin 1 receptor, Tyrosinase-related protein 1, Melanophilin, Canine β-defensin-1, Major Facilitator Superfamily Domain Containing 12 and Agouti-signaling protein (ASIP). Univariable analysis showed there was a meaningful association between the lower back skin extension index and both gender and age (P<0.001 and P=0.048, respectively). Also, there was a possible association between the lower back skin extension index and ASIP Single nucleotide polymorphism (SNP) (R96C) (P=0.078). Linear model analysis showed there was a significant association between the lower back skin extension index and gender (P<0.001), and there was a tendency of the association between the lower back skin extension index and ASIP SNP (R96C) (P=0.098). In addition, there was an association between gender and age for the skin extension index. (P=0.048). Therefore, these results suggest that a greater risk of skin extensibility in toy poodle could be related to being female and the ASIP SNP (R96C), because these factors were associated with higher lower back skin extension index.

PSII-7 Farrowing age is a predictor of sow lifetime performance

Sow lifetime performance can be predicted by sow performance at an early age; however, few studies have examined the relationship between farrowing age (FA) after parity 1 and sow lifetime performance. Therefore, our objective was to examine the association between FA in different parities and sow lifetime performance. Data were extracted from 198,043 sows entered into 155 Spanish herds between 2011 - 2013 and removed between 2011 - 2016. The 1st to 99th percentiles of FA records were analyzed, with FA defined as the number of days from birth to the farrowing date in each parity. A two-level linear mixed-effects model was applied to examine the relationship between FA and lifetime performance of sows (SAS University Edition). Means of FA + SD (range) in parities 1 and 3 were 368.4 + 34.8 (238 - 460) days and 663.5 + 41.4 (501 - 773) days, respectively. The ranges of FA in parity 1 and 3 were 238 - 460 days and 501 - 773 days, respectively. Lifetime performance decreased with higher FA in both parities. For example, in parity 1, as FA increased from 290 to 410 days, lifetime piglets born alive (PBA) decreased by 4.4 piglets, annualized lifetime PBA decreased by 3.5 piglets and nonproductive days increased by 16.8 days. Similarly, in parity 3, as FA increased from 590 to 710 days, lifetime PBA decreased by 5.3 piglets, annualized lifetime PBA decreased by 3.0 piglets and nonproductive days increased by 39.5 days. Also, sows with a lower FA in parity 1 had fewer PBA in that parity than sow with a higher FA (P &lt; 0.05). However, they also had fewer nonproductive days and a shorter weaning-to-first-mating interval and more annualized lifetime PBA. Therefore, these data indicate that FA can be used to predict lifetime performance of the sows.

PSII-11 Herd size associated with sow lifetime performance in Spanish breeding herds

It is critical for producers to maximize sows’ reproductive potential in commercial herds in order to improve economic efficiency. While it is generally known that large herds have better reproductive performance than small herds, few studies have assessed how much the lifetime reproductive performance of sows is associated with herd size. Therefore, our objective was to examine the relationship between six herd size groups and sow lifetime performance. Data were extracted from 166,335 sows which were entered into 155 Spanish breeding herds from 2011 - 2013 and removed by 2017. Herds were categorized into six groups based on the 10th, 25th, 50th, 75th and 90th percentiles of average sow inventory in 2016: 87 - 195, 196 - 342, 343 - 596, 597 - 1,025, 1,026 - 2,152 and 2,153 - 3,669 sows. A two-level linear mixed-effects model was applied to examine the relationship between herd size and reproductive performance of sows (SAS University Edition). No differences were found between herd size groups and either lifetime total born or lifetime piglets born alive. However, the largest herd group had 23.0 fewer lifetime nonproductive days (NPD), and 2.1 more annualized lifetime piglets weaned than the mid-size (343 - 596 sows) herds (P &lt; 0.05). Also, parity at removal was 0.3 lower in the largest herds than the mid-size herds (P &lt; 0.05). Furthermore, the largest herds also had 0.8 - 1.0 days shorter weaning-to-first-mating interval (WMI), 2.8 - 4.9% higher farrowing rates and 10.2 - 11.9 days shorter repeat intervals than the mid-size herds (P &lt; 0.05). In conclusion, the shorter WMI, fewer NPD and improved reproductive productivity in the largest herds suggest that these herds have better lactational management and quicker culling decision making than mid-size herds.

Five risk factors and their interactions of probability for a sow in breeding herds having a piglet death during days 0-1, 2-8 and 9-28 days of lactation

Background

Increasing preweaning piglet mortality is a concern for veterinarians and producers in relation to sow performance and piglet welfare. Our objectives were (1) to characterize pre-weaning piglet mortality risk for sows (PWM) during early (0–1 days), mid- (2–8 days) and late (9–28 days) lactation and (2) to quantify the following five factors and their interactions, parity, number of piglets born alive (PBA), number of stillborn piglets (SB), gestation length (GL) and season for PWM during the three lactation phases.

Methods

Data obtained from 264,333 parity records of 55,635 sows farrowed in 2015 and 2016 from 74 Spanish herds. Three multi-level mixed-effects logistic regression models were separately applied for PWM during three lactation phases, which was analyzed as whether or not a sow had a piglet death (i.e. probability of a sow having a piglet death) in each phase.

Results

PWM during early, mid- and late lactation were 36.9, 27.0 and 15.4%, respectively. As PBA increased from 11 or less to 16 or more pigs, PWM during early and mid-lactation increased by 15.8 and 6.0%, respectively, but there was no increase during late lactation. Also, as GL decreased from 117–120 to 110–113 days, PWM during early, mid- and late lactation increased by 7.5, 6.8 and 1.5%, respectively. Additionally, PWM during the respective lactation phases increased by 8.3, 5.2 and 1.0%, as SB increased from 0 to 3 or more pigs. During early lactation, parity 1 sows had 2.1% lower PWM than parity 5 or higher sows, but during mid- and late lactation they had 4.2% higher PWM (P < 0.05). However, there was no difference between summer and winter for PWM during early lactation (P = 0.26).

Conclusion

Management practices to reduce PWM need to take account of these factors, and be modified for different phases. For example, during early lactation special care should be given to piglets born to parity 5 or higher sows farrowing 16 or more PBA, having 3 or more SB or GL 110–113 days, whereas during mid- and late lactation more care should be given to piglets born to parity 1 sows with the same PBA, GL and SB conditions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40813-021-00231-0.

Timing and temperature thresholds of heat stress effects on fertility performance of different parity sows in Spanish herds

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 (Tmax) 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 Tmax in different weeks around weaning or service events. The ratios for WSI were calculated between groups of sows exposed to Tmax ≥ 27 °C or <27 °C in each week before weaning, with the Tmax 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 Tmax 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 Tmax in the critical week. The breakpoint in the best-fit model was considered to be the threshold Tmax. 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 Tmax leading to prolonged WSI was 17 °C for parity 1 sows and 25 °C for parity 2 or higher sows. Increasing Tmax 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 Tmax 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 Tmax 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.

PSVI-2 Rising 10-year Trend in Piglet Pre-weaning Mortality in Breeding Herds Associated with Sow Herd Size and Number of Piglets Born Alive

The objectives of the present study were to explore the trend in preweaning mortality (PWM) and related measurements such as piglets born alive (PBA), stillborn piglets, herd productivity and herd size in sow herds over a 10-year period; and 2) to examine the relationships between PWM and the related measurements. Herd-level annual data from 2007–2016 for 91 herds in Spain were abstracted from a sow database compiled by a veterinary consultancy firm. The database software automatically calculated herd-level PWM (%) as follows: the total number of piglets born alive to a sow completely weaned during a year (TPBA) minus the total number of piglets weaned by the completely weaned sow during the year divided by TPBA x 100. All the statistical analyses were performed using SAS University Edition. A growth curve model was applied to incorporate correlations for all of the observations arising from the same farm. Herd means of PWM (SD) increased from 11.9 (4.1) % to 14.4 (3.2) %, and mean PBA increased by 1.9 pigs. Mean age of piglet death during lactation increased by 3.8 days, and there was a significant effect of increased year on herd size and the number of piglets weaned per sow per year (PSY; P &lt; 0.05). Higher PWM was associated with more PBA, more stillborn piglets and small herds (lower than the median size: &lt; 570 sows; P &lt; 0.05). Also, as PBA increased from 9 to 14 pigs, PWM in large herds (&gt; 570 sows) increased by only 6.6%, compared with 9.6% in small herds. Furthermore, as PWM decreased from 18 to 8%, herd productivity measured as PSY increased by 2.2 pigs in large herds, but only by 0.6 pigs in small herds. In conclusion, the effect of increased PBA on PWM was alleviated more in large herds than in small herds. Also, the impact of decreased PWM on herd productivity was greater in large herds than in small herds.

PSVI-6 Thresholds of Outdoor Temperatures on Fertility Measures of Different Parity Sows in Spanish Herds

High temperature is one of the environmental factors which impair sow fertility such as weaning-to-first-mating interval (WMI) and farrowing rate especially in parity 1 sows. The objective of this study was to explore thresholds of temperature damaging fertility in different parity sows. Data of sows serviced from 2011 to 2016 in 142 herds were coordinated with daily maximum temperature (Tmax) from 31 weather stations close to the herds. A two-stage approach was used to determine the best fit model. In the first stage, means and their variance-covariance matrix in each degree Celsius were estimated by a mixed model. Then, piecewise models with a different breakpoint were fitted to the estimates by generalized least squares. Medians of WMI in parity 1 and 2 or higher sows were 5 and 4 days, respectively. Farrowing rates in different parity sows were 85.0–88.7%. The thresholds of mean Tmax during lactation leading to a prolonged WMI were 16 and 23–25°C for parity 1 and 2 higher sows, respectively. The 10°C increase in Tmax from the thresholds delayed WMI in parity 1 and 2 or higher sows by 0.62 and 0.46–0.49 days, respectively (P &lt; 0.01). Meanwhile, the thresholds of mean Tmax from 21 to 14 days before service leading to reductions in farrowing rate were 21, 19 and 21–22°C for parity 0, 1 and 2 or higher sows, respectively. As the Tmax increased by 10°C from the thresholds, farrowing rate in parity 0–1 and 2 or higher sows decreased by 2.9 and 2.2–2.6%, respectively (P &lt; 0.01). Lactating sows in parity 1 suffered from heat stress at a relatively low outdoor temperature. This implies that the temperature is warmer in lactating barns than in outdoor. We recommend changing thermostat set at barns in spring from those in winter in order to increase ventilation rates earlier.

A 10-year trend in piglet pre-weaning mortality in breeding herds associated with sow herd size and number of piglets born alive

BACKGROUND

Piglet pre-weaning mortality (PWM) is one of the biggest problems regarding sow performance and piglet welfare. Recently, PWM has increased in some countries, but it is not known if there are similar increases in other countries, nor whether increased PWM is related to either increased numbers of piglets born alive (PBA) or to sow herd size. So, the objectives of the present study were 1) to explore the trend in PWM in Spanish sow herds over a recent 10-year period, along with related measurements such as PBA, stillborn piglets, herd productivity and herd size; and 2) to examine the relationships between PWM and the related measurements.

METHODS

Herd-level annual data from 2007 to 2016 for 91 herds in Spain were abstracted from a sow database compiled by a veterinary consultancy firm that asked client producers to mail data files on a regular basis. The database software automatically calculated herd-level PWM (%) as follows: the total number of piglets born alive to a sow completely weaned during a year (TPBA) minus the total number of piglets weaned by the completely weaned sow during the year divided by TPBA × 100. All the statistical analyses were performed by using SAS University Edition. A growth curve model was applied to incorporate correlations for all of the observations arising from the same farm.

RESULTS

Over the 10 years, herd means of PWM (standard deviation) increased from 11.9 (4.1) % to 14.4 (3.2) %, and mean PBA increased by 1.9 pigs. Mean age of piglet death during lactation increased by 3.8 days, and later years were significantly associated with herd size and the number of piglets weaned per sow per year (PSY; P <  0.05). Higher PWM was associated with more PBA, more stillborn piglets and small-to-mid herds (lower than the median size: < 570 sows; P <  0.05). Also, there was a significant interaction between the herd size groups and PBA for PWM (P <  0.05): as PBA increased from 9 to 14 pigs, PWM increased by 9.6% in small-to-mid herds, compared with an increase of only 6.6% in large herds (> 570 sows). Furthermore, as PWM decreased from 18 to 8%, herd productivity measured as PSY increased by 2.2 pigs in large herds, compared with only 0.6 pigs in small-to-mid herds.

CONCLUSION

Large herds were better than small-to-mid herds at alleviating the association between increased PBA and increased PWM. Also, the relationship between decreased PWM and increased herd productivity was improved more in large herds than in small-to-mid herds.

Farm data analysis for lifetime performance components of sows and their predictors in breeding herds

Our objectives in this review are 1) to define the four components of sow lifetime performance, 2) to organize the four components and other key measures in a lifetime performance tree, and 3) to compile information about sow and herd-level predictors for sow lifetime performance that can help producers or veterinarians improve their decision making. First, we defined the four components of sow lifetime performance: lifetime efficiency, sow longevity, fertility and prolificacy. We propose that lifetime efficiency should be measured as annualized piglets weaned or annualized piglets born alive which is an integrated measure for sow lifetime performance, whereas longevity should be measured as sow life days and herd-life days which are the number of days from birth to removal and the number of days from date of first-mating to removal, respectively. We also propose that fertility should be measured as lifetime non-productive days, whereas prolificacy should be measured as lifetime pigs born alive. Second, we propose two lifetime performance trees for annualized piglets weaned and annualized piglets born alive, respectively, and show inter-relationships between the four components of the lifetime performance in these trees. Third, we describe sow and herd-level predictors for high lifetime performance of sows. An example of a sow-level predictor is that gilts with lower age at first-mating are associated with higher lifetime performance in all four components. Other examples are that no re-service in parity 0 and shorter weaning-to-first-mating interval in parity 1 are associated with higher fertility, whereas more piglets born in parity 1 is associated with higher prolificacy. It appears that fertility and prolificacy are independent each other. Furthermore, sows with high prolificacy and high fertility are more likely to have high longevity and high efficiency. Also, an increased number of stillborn piglets indicates that sows have farrowing difficulty or a herd health problem. Regarding herd-level predictors, large herd size is associated with higher efficiency. Also, herd-level predictors can interact with sow level predictors for sow lifetime performance. For example, sow longevity decreases more in large herds than small-to-mid herds, whereas gilt age at first-mating increases. So, it appears that herd size alters the impact of delayed gilt age at first-mating on sow longevity. Increased knowledge of these four components of sow lifetime performance and their predictors should help producers and veterinarians maximize a sow's potential and optimize her lifetime productivity in breeding herds.

Removal of sows in Spanish breeding herds due to lameness: Incidence, related factors and reproductive performance of removed 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.

Increased age at first-mating interacting with herd size or herd productivity decreases longevity and lifetime reproductive efficiency of sows in breeding herds

Background

Our objectives were to characterize sow life and herd-life performance and examine two-way interactions between age at first-mating (AFM) and either herd size or herd productivity groups for the performance of sows. Data contained 146,140 sows in 143 Spanish herds. Sow life days is defined as the number of days from birth to removal, whereas the herd-life days is from AFM date to removal date. Herds were categorized into two herd size groups and two productivity groups based on the respective 75th percentiles of farm means of herd size and the number of piglets weaned per sows per year: large (> 1017 sows) or small-to-mid herds (< 1017 sows), and high productivity (> 26.5 piglets) or ordinary herds (< 26.5 piglets). A two-level liner mixed-effects model was applied to examine AFM, herd size groups, productivity groups and their interactions for sow life or herd-life performance.

Results

No differences were found between either herd size or herd productivity groups for AFM or the number of parity at removal. However, late AFM was associated with decreased removal parity, herd-life days, herd-life piglets born alive and herd-life annualized piglets weaned, as well as with increased sow life days and herd-life nonproductive days (P < 0.05). Also, significant two-way interactions between AFM and both herd size and productivity groups were found for longevity, prolificacy, fertility and reproductive efficiency of sows. For example, as AFM increased from 190 to 370 days, sows in large herds decreased herd-life days by 156 days, whereas for sows in small-to-mid herds the decrease was only 42 days. Also, for the same AFM increase, sows in large herds had 5 fewer sow life annualized piglets weaned, whereas for sows in small-to-mid herds this sow reproductive efficiency measure was only decreased by 3.5 piglets. Additionally, for ordinary herds, sows in large herds had more herd-life annualized piglets weaned than those in small-to-mid herds (P < 0.05), but no such association was found for high productivity herds (P > 0.10).

Conclusion

We recommend decreasing the number of late AFM sows in the herd and also recommend improving longevity and lifetime efficiency of individual sows.

Recurrence patterns and lifetime performance of parity 1 sows in breeding herds with different weaning-to-first-mating intervals

Background

Our objectives were 1) to compare reproductive performance across parities and lifetime performance of parity 1 sows in six weaning-to-first-mating interval groups (WMI 0-3, 4, 5, 6, 7-20 and 21 days or more), 2) to determine the recurrence patterns and repeatability of WMI, and 3) to quantify factors associated with the probability of parity 1 sows having WMI 4 days. Examined data comprised 691,276 parity and 144,052 lifetime records of sows in 155 Spanish herds, served between 2011 and 2016. Mixed-effects models were applied to the data. Variance components analysis determined WMI repeatability.

Results

Proportions of parity 1 sows with WMI 0-3, 4, 5, 6, 7-20 and 21 days or more were 4.1, 30.0, 38.4, 7.9, 12.7 and 6.9%, respectively. Of the parity 1 sows with WMI 0-4 days, 43.3-60.5% had WMI 4 days in later parities, whereas 33.9-48.9% of those with WMI ≥5 days had WMI 5 days; WMI repeatability was 0.11. Parity 1 sows with WMI 4 or 5 days had 0.3-2.1 days shorter WMI in later parities than those with WMI ≥7 days (P <  0.05). Parity 1 sows with WMI 4 or 5 days also had 0.6-2.1 more annualized lifetime piglets born alive than those with WMI ≥7 days (P <  0.05). Notably, parity 1 sows with WMI 4 days had 0.3 more annualized lifetime piglets born alive than those with WMI 5 days (P <  0.05).

Conclusion

The WMI in parity 1 could be a useful predictor for subsequent reproductive performance and lifetime performance of sows.

Incidences and risk factors for prolapse removal in Spanish sow herds

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 16^th 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.

High-performing farms exploit reproductive potential of high and low prolific sows better than low-performing farms

Background

Our objective was to examine the impact of farm effects and sow potential on various aspects of sow performance. We examined the interaction between sow prolificacy groups categorized at parity 1 and farm productivity groups for reproductive performance across parities, and lifetime performance. Data included 419,290 service records of 85,096 sows, on 98 Spanish farms, from first-service as gilts to removal, that were served between 2008 and 2013. Farms were categorized into three productivity groups based on the upper and lower 25th percentiles of the farm means of annualized lifetime piglets weaned per sow over the 6 years: high-performing (HP), intermediate-performing (IP), and low-performing (LP) farms. Also, parity 1 sows were categorized into three groups based on the upper and lower 10th percentiles of piglets born alive (PBA) as follows: 15 piglets or more (H-prolific), 8 to 14 piglets, and 7 piglets or fewer (L-prolific). The farm groups represent farm effects, whereas the sow groups represent sow potential. Linear mixed effects models were performed with factorial arrangements and repeated measures.

Results

Mean parity at removal (4.8 ± 0.01) was not associated with three farm productivity groups (P = 0.43). However, HP farms had 7.7% higher farrowing rates than LP farms (P <  0.05). As a result, H-prolific and L-prolific sows on HP farms had 29.7 and 30.7 fewer non-productive days during lifetime than the respective sows on LP farms (P <  0.05). Furthermore, the H-prolific and L-prolific sows on HP farms had 4.9 and 6.2 more annualized piglets weaned than respective H-prolific and L-prolific sows on LP farms (P <  0.05), which was achieved by giving birth to 0.8–1.0 and 1.4–1.7 more PBA per litter, respectively, than on HP farms during parities 2–6 (P <  0.05). During the first parity, HP farms had 18.8% H-prolific sows compared to 6.2% on LP farms.

Conclusion

Farm effects substantially affected lifetime performance of sows. Higher lifetime productivity of sows on HP farms was achieved by higher farrowing rate, fewer non-productive days, more PBA and more piglets weaned per sow, regardless of prolific category of the sows.

Culling in served females and farrowed sows at consecutive parities in Spanish pig herds

Background

The objectives of our study were 1) to characterize culling and retention patterns in parities 0 to 6 in served females and farrowed sows in two herd groups, and 2) to quantify the factors associated with by-parity culling risks for both groups in commercial herds. Lifetime data from first-service to removal included 465,947 service records of 94,691 females served between 2008 and 2013 in 98 Spanish herds. Herds were categorized into two groups based on the upper 25th percentile of the herd means of annualized lifetime pigs weaned per sow: high-performing (> 24.7 pigs) and ordinary herds (≤ 24.7 pigs). Two-level log-binomial regression models were used to examine risk factors and relative risk ratios associated with by-parity culling risks.

Results

Mean by-parity culling risks (± SE) for served females and farrowed sows were 5.9 ± 0.03 and 12.4 ± 0.05%, respectively. Increased culling risks were associated with sows that farrowed 8 or fewer pigs born alive (PBA). Also, farrowed sows in high-performing herds in parities 2 to 6 had 1.5–5.6% higher culling risk than equivalent parity sows in ordinary herds (P < 0.05). Furthermore, sows in parities 1 to 6 that farrowed 3 or more stillborn piglets had 2.2–4.8% higher culling risk than for sows that did not farrow any stillborn piglets (P < 0.05). For served sows, culling risk in parity 1 to 6 sows with a weaning-to-first-service interval (WSI) of 7 days or more were 2.2–3.9% higher than equivalent parity sows with WSI 0–6 days (P < 0.05). With regard to relative risk ratios, served sows with WSI 7 days or more were 1.56–1.81 times more likely to be culled than those with WSI 0–6 days.

Conclusion

Producers should reduce non-productive days by culling sows after weaning, instead of after service or during pregnancy. Also, producers should pay special attention to sows farrowing stillborn piglets or having prolonged WSI, and reconsider culling policy for mid-parity sows when they farrow 8 or fewer PBA.

Electronic supplementary material

The online version of this article (10.1186/s40813-018-0080-y) contains supplementary material, which is available to authorized users.

Characteristics and risk factors for severe repeat-breeder female pigs and their lifetime performance in commercial breeding herds

BACKGROUND

Repeat-breeder females increase non-productive days (NPD) and decrease herd productivity and profitability. The objectives of the present study were 1) to define severe repeat-breeder (SRB) females in commercial breeding herds, 2) to characterize the pattern of SRB occurrences across parities, 3) to examine factors associated with SRB risk, and 4) to compare lifetime reproductive performances of SRB and non-SRB females. Data included 501,855 service records and lifetime records of 93,604 breeding-female pigs in 98 Spanish herds between 2008 and 2013. An SRB female pig was defined as either a pig that had three or more returns. The 98 herds were classified into high-, intermediate- and low-performing herds based by the upper and lower 25th percentiles of the herd mean of annualized lifetime pigs weaned per sow. Multi-level mixed-effects logistic regression models with random intercept were applied to the data.

RESULTS

Of 93,604 females, 1.2% of females became SRB pigs in their lifetime, with a mean SRB risk per service (± SEM) of 0.26 ± 0.01%. Risks factors for becoming an SRB pig were low parity, being first-served in summer, having a prolonged weaning-to-first-mating interval (WMI), and being in low-performing herds. For example, served gilts had 0.81% higher SRB risk than served sows (P < 0.01). Also, female pigs in a low-performing herd had 1.19% higher SRB risks than those in a high-performing herd. However, gilt age at-first-mating (P = 0.08), lactation length (P = 0.05) and number of stillborn piglets (P = 0.28) were not associated with becoming an SRB female. The SRB females had 14.4-16.4 fewer lifetime pigs born alive, 42.8-91.3 more lifetime NPD, and 2.1-2.2 lower parities at culling than non-SRB females (P < 0.05).

CONCLUSIONS

We recommend that producers closely monitor the female pig groups at higher risk of becoming an SRB.

Sow housing associated with reproductive performance in breeding herds

Female pigs in breeding herds can be managed through four phases-gilt development, breeding, gestation, and lactation-during which they may be housed in group or individual pens, stalls, or on pasture. In this review, we focus on housing environments that optimize outcomes during gestation and lactation. Appropriate housing is important during early gestation, to protect embryos and to confirm pregnancy, and from mid-to-late gestation, to ensure sufficient nutrition to increase placental and fetal growth. No difference in the number of pigs born alive were reported between group housing and individual stall housing, although more risk factors for reproductive performance are associated with group housing than stall housing including genetics, bedding, floor space allowance, group size, social ranking, and parity. Furthermore, lameness in pregnant pigs is more frequent in group housing than in stall housing. Housing during lactation helps protect piglets from being crushed or from contracting disease, and can foster the transfer of enough colostrum from mother to piglets. Indeed, lactating sows in pen housing tend to have higher pre-weaning mortality and lighter litter weights than those in crated housing.

Factors for improving reproductive performance of sows and herd productivity in commercial breeding herds

We review critical factors associated with reproductive performance of female breeding pigs, their lifetime performance and herd productivity in commercial herds. The factors include both sow-level and herd-level factors. High risk sow-level groups for decreasing reproductive performance of female pigs are low or high parity, increased outdoor temperature, decreased lactation feed intake, single inseminations, increased lactation length, prolonged weaning-to-first-mating interval, low birth weight or low preweaning growth rate, a few pigs born alive at parity 1, an increased number of stillborn piglets, foster-in or nurse sow practices and low or high age at first-mating. Also, returned female pigs are at risk having a recurrence of returning to estrus, and female pigs around farrowing are more at risk of dying. Herd-level risk groups include female pigs being fed in low efficiency breeding herds, late insemination timing, high within-herd variability in pig flow, limited numbers of farrowing spaces and fluctuating age structure. To maximize the reproductive potential of female pigs, producers are recommended to closely monitor females in these high-risk groups and improve herd management. Additionally, herd management and performance measurements in high-performing herds should be targeted.

Recurrence patterns and factors associated with regular, irregular, and late return to service of female pigs and their lifetime performance on southern European farms

A return-to-service occurrence increases nonproductive days of female pigs and decreases herd productivity. The objectives of the present study were 1) to characterize 3 return types based on reservice intervals in female pigs on southern European farms, 2) to determine return risks and recurrence patterns for these types of returns, and 3) to assess lifetime performance of females with the 3 types of returns. We analyzed 653,528 service records and lifetime records of 114,906 females on 125 farms between 2008 and 2013. Reservice intervals were categorized into 3 groups: regular returns (RR: 18 to 24 d), irregular returns (IR: 25 to 38 d), and late returns (LR: 39 d or later). Multilevel generalized linear models were applied to the data. There were 64,385 reservice records (9.9%), with mean risks of RR, IR, and LR per service (±SEM) of 3.6% ± 0.06%, 2.5% ± 0.05%, and 3.0% ± 0.06%, respectively. Of the 43,931 first-returned females, 32.7% had a second return in the same or later parity. Also, 18.8%, 10.2%, and 11.6% of females that had RR, IR, and LR first returns, respectively, had a second return of the same return type. Summer servicing was associated with greater RR, IR, and LR risks in gilts. Also, increased gilt age at first mating was associated with RR ( = 0.03) and LR risk ( < 0.01) but not with IR risk ( = 0.53). For sows, factors associated with greater RR, IR, or LR risks were summer servicing, lower parity, farrowing more stillborn piglets, and having a weaning-to-first-mating interval of 7 d or more ( < 0.01). In lifetime, 33.5% of serviced females had 1 or more returns. These returned females had 41.5 more lifetime nonproductive days than nonreturn females but also 1.9 more lifetime pigs born alive ( < 0.01). We recommend that producers closely monitor females in high-risk groups to reduce their return-to-service intervals.

High lifetime and reproductive performance of sows on southern European Union commercial farms can be predicted by high numbers of pigs born alive in parity one

Our objectives were 1) to compare reproductive performance across parity and lifetime performance in sow groups categorized by the number of pigs born alive (PBA) in parity 1 and 2) to examine the factors associated with more PBA in parity 1. We analyzed 476,816 parity records and 109,373 lifetime records of sows entered into 125 herds from 2008 to 2010. Sows were categorized into 4 groups based on the 10th, 50th, and 90th percentiles of PBA in parity 1 as follows: 7 pigs or fewer, 8 to 11 pigs, 12 to 14 pigs, and 15 pigs or more. Generalized linear models were applied to the data. For reproductive performance across parity, sows that had 15 or more PBA in parity 1 had 0.5 to 1.8 more PBA in any subsequent parity than the other 3 PBA groups ( P< 0.05). In addition, they had 2.8 to 5.4% higher farrowing rates in parities 1 through 3 than sows that had 7 or fewer PBA (P < 0.05). However, there were no differences between the sow PBA groups for weaning-to-first-mating interval in any parity (P ≥ 0.37). For lifetime performance, sows that had 15 or more PBA in parity 1 had 4.4 to 26.1 more lifetime PBA than sows that had 14 or fewer PBA (P < 0.05). Also, for sows that had 14 or fewer PBA in parity 1, those that were first mated at 229 d old (25th percentile) or earlier had 2.9 to 3.3 more lifetime PBA than those first mated at 278 d old (75th percentile) or later (P < 0.05). Factors associated with fewer PBA in parity 1 were summer mating and lower age of gilts at first mating (AFM; P < 0.05) but not reservice occurrences (P = 0.34). Additionally, there was a 2-way interaction between mated month groups and AFM for PBA in parity 1 (P < 0.05); PBA in parity 1 sows mated from July to December increased nonlinearly by 0.3 to 0.4 pigs when AFM increased from 200 to 310 d old (P < 0.05). However, the same rise in AFM had no significant effect on the PBA of sows mated between January and June (P ≥ 0.17). In conclusion, high PBA in parity 1 can be used to predict that a sow will have high reproductive performance and lifetime performance. Also, the data indicate that the upper limit of AFM for mating between July and December should be 278 d old.

Climatic factors associated with reproductive performance in English Berkshire pigs and crossbred pigs between Landrace and Large White raised in a subtropical climate region of Japan

Our objective was to characterize Berkshire female pigs associated with climatic factors by examining the interactions between two pig groups (pure English Berkshire females and crossbred females between Landrace and Large White) for reproductive performance in a humid subtropical zone. We analyzed 63,227 first-service records of 11,992 females in 12 herds. Climate data were obtained from four weather stations located close to the herds. Mean daily maximum temperatures (Tmax) and daily average relative humidity (ARH) for different time periods around servicing and farrowing of each female were coordinated with that female's reproductive performance data. Multilevel mixed-effects models were applied to the data. There were two-way interactions between the pig groups and either Tmax or ARH for weaning-to-first-mating interval (WMI) and number of total pigs born (TPB; P < 0.05). The WMI in Berkshire sows increased by 0.64 days as Tmax increased from 20 to 30 °C (P < 0.05), whereas in crossbred sows it only increased by 0.09 days over the same Tmax range. In contrast, WMI in Berkshire sows only increased by 0.01 days as ARH increased from 60 to 80 % (P < 0.05), whereas in crossbred sows it increased by 0.32 days. In Berkshire females, TPB decreased by 0.3 pigs as Tmax increased from 20 to 30 °C (P < 0.05), whereas that in crossbred females decreased by 0.4 pigs (P < 0.05). Therefore, we recommend producers apply advanced cooling systems for Berkshire females.

Lipoprotein cholesterol and triglyceride concentrations associated with dog body condition score; effect of recommended fasting duration on sample concentrations in Japanese private clinics

The objectives of this study were to survey clinics’ guidance about recommended fasting duration (FD) prior to lipoprotein analysis, and to characterize lipoprotein cholesterol and triglyceride concentrations in obese and overweight dogs categorized on the basis of the 5-point body condition score (BCS) scale. A dataset was created from lipoprotein analysis medical records of 1,538 dogs from 75 breeds in 354 clinics from 2012 to 2013. A phone survey was conducted to obtain the clinics’ FD. Two-level linear mixed-effects models were applied to the data. Over 50% of the clinics said they recommended fasting for 12 hr or more. Dogs in clinics with FD 12 hr or more had lower chylomicron triglyceride concentrations than those in clinics with FD less than 8 hr (P=0.05). Mean (± SEM) BCS at sampling was 3.7 ± 0.02. Obese and overweight dogs had higher very low density lipoprotein (VLDL) and high density lipoprotein (HDL) cholesterol and triglyceride concentrations than ideal dogs (P<0.05), but no such difference was found for low density lipoprotein cholesterol and triglyceride concentrations (P≥0.07). Across all BCS, as dog age rose from 0 to 8 years old, HDL cholesterol concentrations decreased by 13.5 mg/dl, whereas VLDL triglyceride concentrations increased by 81.7 mg/dl (P<0.05). In conclusion, FD of 8 hr or less may affect lipoprotein lipid concentrations. Obese and overweight dogs were characterized as having high VLDL and HDL cholesterol and triglyceride concentrations.

Lifetime reproductive performance and survival of English Berkshire female pigs raised in commercial herds in subtropical Japan

The objective of the present study was to compare lifetime reproductive performance and survival probability of English Berkshire female pigs and crossbred females in a subtropical region of Japan. We analyzed records of 20,417 females entered into the 12 herds in Southern Japan from 2003 to 2007. Generalized linear mixed-effects models were conducted to compare the lifetime reproductive performance of the Berkshire and crossbred females. Multilevel mixed-effects models were conducted to compare the lifetime reproductive performance of the Berkshire and crossbred females. Also, a multilevel proportional hazard model was used to examine the survival probabilities for the two breeds. Berkshire gilts were 39.8 days older at first-mating than crossbred gilts (P = 0.05). The pigs born alive (PBA) in Berkshire and crossbred gilts increased from 5.8 to 6.9 pigs and from 10.7 to 11.1 pigs, respectively, as age at first-mating increased from 220 to 310 days old (P < 0.05). More Berkshire gilts were culled for reproductive failure than crossbred gilts (7.5 vs. 3.8 %; P < 0.05). Also, Berkshire females had 2.7 lower parity at removal, 224.4 days lower reproductive herd-life, and 4.2 pigs fewer average lifetime PBA than crossbred females (P < 0.05) and tended to have a lower survival probability (P = 0.05). In summary, Berkshire females had later puberty, were more sensitive to age at first-mating for increasing PBA, and had lower fertility and a lower survival probability than crossbred females in commercial herds.

Interactions between pre- or postservice climatic factors, parity, and weaning-to-first-mating interval for total number of pigs born of female pigs serviced during hot and humid or cold seasons

The objective of this study was to examine interactions between climatic factors, parity, and weaning-to-first-mating interval (WMI) for total number of pigs born at subsequent parity (TPB) of female pigs serviced during 2 seasons. The present study analyzed records of 27,739 gilts and 127,670 parity records of sows in 95 Japanese herds; the records included females that were serviced between June and September (hot and humid season) or between December and March (cold season) in 2007 through 2009. The climate data were obtained from 20 weather stations located close to the studied herds. Mean daily maximum temperatures (Tmax), mean daily minimum temperatures (Tmin), and daily average relative humidity (RH) for 21 d preservice and 15 d postservice for each female were coordinated with that female's reproductive data. Linear regression models with random intercept and slopes were applied to the data. Mean TPB (±SEM) was 11.9 ± 0.01 pigs. Mean values (ranges) of Tmax in the hot and humid season and Tmin in the cold season were 28.4 (13.6 to 39.8°C) and 2.0°C (-13.2 to 17.6°C), respectively. Also, mean RH in the hot and humid season and the cold season were 73.2 (35 to 98%) and 65.2% (25 to 99%), respectively. In the hot and humid season, TPB in gilts decreased by 0.05 pigs for each degree Celsius increase in preservice Tmax (P < 0.05). However, there was no association between gilt TPB and either postservice Tmax (P = 0.11) or pre- and postservice RH (P ≥ 0.66). In sows, as preservice Tmax increased from 25 to 30°C, TPB in parity groups 1 and 2 or higher decreased by 0.6 and 0.4 pigs, respectively (P < 0.05). Also, sow TPB decreased by 0.1 to 0.4 pigs as postservice Tmax increased from 25 to 30°C (P < 0.05). In sows with WMI of 0 to 12 d, TPB decreased by 0.2 to 0.5 pigs as pre- or postservice Tmax increased from 25 to 30°C (P < 0.05). However, in sows with WMI of 13 d or more, TPB was not associated with pre- or postservice Tmax (P ≥ 0.10). As preservice Tmax increased from 25 to 30°C, TPB in sows under 81.6% RH (90th percentile) decreased by 0.5 pigs (P < 0.05), whereas TPB in sows under 65.7% RH (10th percentile) decreased by only 0.3 pigs (P < 0.05). Postservice RH in the hot and humid season was not associated with sow TPB (P = 0.18). During the cold season there was no association between TPB and pre- or postservice Tmin (P ≥ 0.09) or RH (P ≥ 0.45). Therefore, we recommend that producers apply cooling management for females during periservice in summer to increase TPB.

Dog age and breeds associated with high plasma cholesterol and triglyceride concentrations

The objectives of this study were to set specific dog breed and sex standards for total cholesterol (T-Cho) and total triglyceride (T-TG) concentrations in dogs and to quantify the associations between dog age and concentrations of both lipids for different breeds. Increased age was associated with higher T-Cho and T-TG concentrations in all five breed groups (P<0.05); T-Cho concentrations increased by 62.5 mg/dl between 9 and 16 years of age, and T-TG concentrations increased by 4.8 mg/dl per year of age (P<0.05). Miniature Schnauzers had the highest T-Cho concentrations of the studied breeds, while Miniature Dachshunds had the lowest concentrations (P<0.05). Veterinarians should consider dog age and breed when they use the lipid concentrations for diagnostic purposes.

Herd management procedures and factors associated with low farrowing rate of female pigs in Japanese commercial herds

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.

Standard operating procedures for sows and piglets in farrowing and lactation in Japanese commercial herds

The objectives of the present study were to advance the development of standard operating procedures for sows and piglets during farrowing and lactation in Japanese herds by surveying management procedures and to examine the relationships between the procedures and herd reproductive performance. In 2009, 115 herds using the same recording system were asked to complete a questionnaire about their management procedures. Data from 96 (83.5%) returned questionnaires were coordinated with the respective herd reproductive performance. The participating herds were classified into two groups based on the upper 25th percentile of pigs weaned per mated female per year: high-performing (>23.8 pigs) or ordinary herds. ANOVA was used to compare the procedures between two herd groups. Modeling with backward elimination was performed to establish the most important procedures for herd performance. More high-performing herds practiced farrowing induction and high-performing herds also had a higher percentage of farrowing-induced sows than ordinary herds (P<0.05). Modeling showed that herds feeding lactating sows with dietary fiber had 1.4% lower preweaning mortality risk than those that did not (P<0.05). Herds practicing fostering techniques or using nurse sows had 0.2 kg heavier average pig weaning weight than those not using these procedures (P<0.05). There was no association between pigs born alive and any of the surveyed management procedures. Based on these results, we recommend improving performances in breeding herds by feeding lactating sows with dietary fiber, performing fostering techniques and using nurse sows.

Swine herds achieve high performance by culling low lifetime efficiency sows in early parity

Sow lifetime performance and by-parity performance were analyzed using a 3 by 3 factorial design, comprising 3 herd productivity groups and 3 sow efficiency groups. Data was obtained from 101 Japanese herds, totaling 173,526 parity records of 34,929 sows, for the years 2001 to 2006. Sows were categorized into 3 groups based on the lower and upper 25th percentiles of the annualized lifetime pigs born alive: low lifetime efficiency sows (LE sows), intermediate lifetime efficiency sows or high lifetime efficiency sows. Herds were grouped on the basis of the upper and lower 25th percentiles of pigs weaned per mated female per year, averaged over 6 years: high-, intermediate- or low-performing herds. Mixed-effects models were used for comparisons. LE sows in high-performing herds had 57.8 fewer lifetime nonproductive days and 0.5 earlier parity at removal than those in low-performing herds (P<0.05). The number of pigs born alive of LE sows continuously decreased from parity 1 to 5, whereas those of high lifetime efficiency sows gradually increased from parity 1 to 4 before decreasing up to parity ≥ 6 (P<0.05). In conclusion, the LE sows have a performance pattern of decreasing number of pigs born alive across parity. The present study also indicates that high-performing herds culled potential LE sows earlier than the other herds.

Associations between age of gilts at first mating and lifetime performance or culling risk in commercial herds

Age of gilts at first mating (AFM) is a factor associated with reproductive performance of female pigs. The objectives of the present study were to compare AFM and reproductive performance across parity between three herd groups based on a productivity measurement and to determine lifetime performance by AFM and the herd groups. The female data included 38,212 mated gilts entered between 2001 and 2003, and the herd data included mean measurements from 2001 to 2006 in 101 herds. The average female inventory of the 101 herds was 370.2 females. Females were categorized into five groups: AFM 188-208, 209-229, 230-250, 251-271 or 272-365 days. Three herd groups were formed on the basis of the upper and lower 25th percentiles of pigs weaned per mated female over six years: high-, intermediate- and low-performing herds. Multilevel mixed-effects models were performed to analyze comparisons. The AFMs (± SEM) in the high-, intermediate- and low-performing herds were 239.5 ± 0.22, 247.4 ± 0.21 and 256.7 ± 0.35 days, respectively. As the AFM increased from 209-229 to 272-365 days, annualized lifetime pigs born alive (PBA) decreased from 18.2 to 15.3 pigs, and the number of parities at removal decreased from 4.8 to 4.1 (P<0.05). In parity 1, females with an AFM of 209-229 days had fewer PBA, but had a lower culling risk and shorter weaning-to-first mating interval than those with an AFM of 251-271 days (P<0.05). In conclusion, we recommend management practices such as boar exposure to hasten puberty in gilts and decrease AFM.

Culling intervals and culling risks in four stages of the reproductive life of first service and reserviced female pigs in commercial herds

The objectives of this study were to measure culling intervals and culling risks in the four stages of the reproductive life of female pigs and to compare culling intervals between the number of services and between herd groups, based on herd productivity. We also compared survival patterns of females pigs between these herd groups. Our data set included lifetime records of 52,792 females born between 2001 and 2004 in 101 commercial herds. Two herd groups were selected on the basis of the upper 25th percentile of pigs weaned per mated female per 5 yr between 2002 and 2006, namely the high-performing herds, and ordinary herds. Culled females were also allocated into four groups based on the stages of their reproductive life when culled: unmated gilts, mated gilts, unmated sows, and mated sows. Culling intervals in unmated gilts and mated gilts were defined as the number of days from birth to culling and from first mating to culling, respectively. Culling intervals in unmated sows and mated sows were the number of days from weaning to culling. The number of services was categorized into two groups: first service and reservice groups. Multilevel linear mixed-effects models and survival analysis were performed. Culling intervals (+/-SEM) in unmated gilts, mated gilts, unmated sows, and mated sows were 302.9+/-1.16, 98.4+/-0.92, 14.3+/-0.12, and 89.6+/-0.42 d, respectively. Culling risks in the four groups were 5.6%, 7.1%, 58.0%, and 29.3%, respectively. In unmated gilts, mated gilts, and mated sows, the culling intervals in the high-performing herds were 43.0, 18.9, and 16.0 d shorter than those in ordinary herds, respectively (P<0.05), but no difference was found between the herd groups for the culling interval of unmated sows. For mated sows in the reservice group, culling intervals of high-performing herds were >or=13.7 d shorter than those of the ordinary herds (P<0.05), but for mated sows in the first service group, there was no difference in the culling interval between the herd groups. The culling hazard from 8 wk postweaning for mated sows in high-performing herds increased more rapidly than that in ordinary herds. In conclusion, to reduce culling intervals and improve herd productivity, we recommend implementing a strict culling policy for mated gilts and mated sows, especially reserviced females.

Factors associated with a single-mating occurrence in first-serviced and reserviced female pigs on commercial farms

This study investigated associations of a single-mating occurrence (SMO) with farrowing rate and pigs born alive (PBA) in first-serviced and reserviced female pigs (females), and identified the factors associated with SMO. The data included 111,334 service and 91,233 farrowing records on 117 farms. A mating was defined as any one insemination (mating) of a female during estrus. Mixed-effects models were used to investigate reproductive performance and factors associated with SMO. In the first-service group, single-mated females had a lower farrowing rate and fewer PBA than multiple-mated females (P<0.05). In the reservice group, single-mated females also had a lower farrowing rate than multiple-mated females (P<0.05), but had PBA similar to multiple-mated females. SMO in first-service and reservice groups were 4.1 and 6.0%, respectively. Gilts were 1.030 times more likely to be mated a single time than sows (P<0.05). Gilts with age at first mating 150-224 and > or = 262 days were 1.010-1.016 times more likely to be mated a single time than those with age at first mating 225-260 days (P<0.05). Sows with weaning-to-first-mating interval > or = 7 days were 1.024-1.030 times more likely to be mated a single time than those with weaning-to-first-mating interval < or = 6 days (P<0.05). Factors associated with a higher SMO were a reservice occurrence, being gilts, low or high ages of gilts at first mating, and prolonged weaning-to-first-mating interval.

Double and triple matings associated with reproductive performance in first-serviced and reserviced female pigs in commercial herds

The objective of this study was to investigate associations of the number of matings and services with reproductive performance in high-performing and ordinary herds. The data included 113,265 service and 92,248 farrowing records in 117 herds. A service included single or more matings of a female pig (female) during a 10-day estrus period. Two herd groups were built on the basis of the upper 25th percentile of pigs weaned per mated female per year: high-performing (> or = 22.8 pigs) and ordinary herds. Mixed-effects models were used to analyze reproductive performance. Relative frequencies (%) of single, double and triple or more matings were 3.4, 27.4, and 69.2% in high-performing herds, respectively, and were 4.6, 59.3 and 36.1% in ordinary herds, respectively. Percentages of reserviced females in high-performing and ordinary herds were 7.3 and 13.0%, respectively. Triple or more-mated (TM) gilts had 3.5% higher farrowing rates than double-mated (DM) gilts (P<0.01), but similar pigs born alive (PBA) to DM gilts in the first service group in both the herd groups. In the first service group, TM sows had 0.8% higher farrowing rates and 0.2 more PBA than DM sows in high-performing herds (P<0.01). In the reservice group, TM gilts and TM sows had farrowing rate similar to DM gilts and DM sows in high-performing herds. In conclusion, performing triple matings was a better practice for first-serviced females than performing double matings. Double matings may be sufficient for reserviced females.

By-parity nonproductive days and mating and culling measurements of female pigs in commercial breeding herds

The objectives of this study were to determine by-parity nonproductive female days (NPD or NPDs) and mating and culling measurements, to determine correlations between by-parity NPDs, mating and culling measurements and herd productivity measurements, and to compare by-parity NPDs between three herd groups (105 herds) with differing reproductive productivities. NPD was defined as the number of days when mated females were neither gestating nor lactating. Correlation analysis and mixed-effects models were performed. On the basis of the 25th and 75th percentiles of pigs weaned per mated female per year, three herd groups were formed: high-, intermediate-, and low-performing herds. The mean NPD of 105 breeding herds (mean +/- SEM) was 52.7 +/- 1.6 days. The NPDs in parities 1, 6 and > or = 7 were higher than those in parities 0, 2, 3 and 4 (P<0.05). High-performing herds had a higher farrowing percentage and lower percentage of reserviced females than low-performing herds (P<0.05). Lower by-parity NPDs were correlated with lower percentages of reserviced females, higher farrowing percentages and lower culling rates from parities 1 to 5 (P<0.05). High-performing herds had NPDs that were > 25 days lower in parities 0 to 3 than low-performing herds (P<0.05). High-performing herds had lower culling rates in parities 2 to 5 and higher culling rates in parities 6 and > or = 7 than low-performing herds (P<0.05). The present study indicates that monitoring the by-parity NPD and mating and culling measurements is a good tool for improvement of herd productivity.

An evaluation of the impact of increased lactation length on the reproductive efficiency of sows in commercial herds

The objective of this study was to evaluate the impact of increased lactation length (LL) on the reproductive efficiency of sows in herds that were performing differently. The present study used 69,314 parity records for 38,532 sows in 114 herds. Two herd groups, high-performing herds and other herds, were formed on the basis of the upper 25th percentile of pigs weaned per mated female per year. Reproductive efficiency was measured as the estimated number of pigs born alive per farrowed sow per year (PBASY) and was calculated as actual subsequent pigs born alive (PBA) multiplied by estimated litters per farrowed sow per year (LSY) for each farrowed sow. The estimated LSY was calculated as 365 days divided by the actual farrowing interval. Multilevel linear mixed-effects models were used. In our evaluation, an interaction between LL and the herd groups was found for the estimated PBASY (P<0.05). The estimated PBASY of high-performing herds did not decrease as LL increased (P>0.10), although the estimated PBASY of the other herds decreased by 0.04 pigs as LL increased by 1 day (P<0.05). As LL increased from 14 to 28 days, the estimated LSY decreased by 0.19 in the two herd groups (P<0.05). Furthermore, as LL increased by 1 day, subsequent PBA increased by 0.08 pigs in high-performing herds and increased by 0.04 pigs in the other herds (P<0.05). Increased LL may not decrease the performance of sows in high-performing herds, but it may decrease the performance in other herds.