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 ß-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.

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.

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.

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 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.

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.

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.

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.

Number of pigs born alive in parity 1 sows associated with lifetime performance and removal hazard in high- or low-performing herds in Japan.

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.

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.

Climatic factors associated with abortion occurrences in Japanese commercial pig herds.

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.